I'm an Automotive Mechanical engineer for 28 years, been in the business for that long and I tell you: Your knowledge and teaching skills are absolutely amazing, congrats man!
I agree ... but don't you think he should emphasize that it's the gear ratio (as he briefly touched on) that determines power and not "Horse Power" ..? WHAT does 5252 have to do with it? Right..?
It is really sad that manufacturers have been forced to "emulate" gear shift on cars with CVT because of a small number of whining customers. They should at least offer an option to enable a "pure" CVT mode where the useless gear shift emulation is turned off and the engine runs at the optimum RPM for any given situation.
I have a 16 accord with cvt I do not hear any shift or difference in engine sound at all runs like a fast golf cart just keeps going faster no increase in sound
A lot of newer CVT equipped vehicles use different drive modes through a button that changes how the stepped portion works, but they usually still resort to stepping at some throttle level unfortunately.
So you have never ridden/driven a quadbike,/UTV.SXS sports machine? They seem to do just fine. CVTs used to be called torque converters so coming into electric engines where 100% of torque is available at 1 RPM why shouldnt we use CVT efficiency over gearing which has been shown in sports SXS's not to be able to match CVTs yet??. "Consumers dont understand it, they don't like it..." minute 1.00
@David M Well, I owned a car with CVT and used over a year, at the end I hated the slow response of CVT. So, I sold the car and bought another with a 6 gear automatic transmission. What a difference!
Ive actually always loved the CVT in my Honda Accords. I always felt it allowed me to stay at peak power "forever" when Im stepping on it which is nice, and it runs much smoother. The only complaint I have is stop and go traffic it sucks. When riding the bottom of the CVT during stop and go you can feel the CVT bottom out all the time. But other than that I love everything about it.
The main problem with CVTs is that while they are theoretically the ideal transmission for performance/efficiency, in practice they are let down by sub par implementation. For example the slow response to changes in throttle input or the low input torque limit, and the high internal friction or less than ideal optimization of the actual gear ratio vs speed/engine load actually means they don't use less fuel than conventional transmissions. There is also a psychological component to it, people actually like hearing engines rev up as they accelerate. If CVTs had always been the norm since cars were first produced people would be fine with it, but because they weren't people are used to the sound of an engine revving up and down, and the engine mantaining a constant speed while the car accelerates just sounds wrong to most people's ears. Sometimes a car with a CVT is faster than one with a conventional transmission, but *feels* slower. And humans are hardly entirely rational and objective in their choices, feelings play a huge part. Besides conventional automatic transmissions already have a continously variable component to them (the torque converter) and with turbos and variable valve technologies engines have never had such broad power and efficiency bands, so there is far less to be gained from a CVT today than we would with for instance a 1970s engine.
I have a 2018 civic EX-T with the CVT in it and when you put it in the sport mode it immediately increases the RPMs to hover between 3-4K as opposed to the standard drive mode which obviously tries to keep you as low as possible. This makes the car feel very very quick and insanely fun to drive as you are always getting the full potential of the engine without any shift points. I understand the reliability issues these have had but if you are leasing or are willing to put that aside, the CVT is leaps and bounds more entertaining to drive than a standard automatic and performs way better. I trust that Honda has a more reliable CVT than what Nissan had so I’m sure the reliability issues aren’t as big as people think
GM made a 2-speed automatic called “power glide”. Yes! Two speeds. A low gear for getting the mass stared into a roll then a variable speed (pressure) that continued across the power curve until max rpm was reached. Essentially a CVT but with a launch gear. Ironically, many top fuel dragsters and funny cars used the power glide because of those properties so much like the properties (young) Jason was outlining in the video! Great job, Jason!
Good point, but of course it is not quite the same, as the transmission did not change the gear ratio. (I'm not considering the launch gear in this discussion.) A cvt will change the ratio *as well as* keep the engine at peak power - a powerful combination. The powerglide relies on slip to put the engine at (semi-close) to peak power, but the power is being delivered to a single ratio, so the mechanical advantage is not there as is with the cvt.
The torque converter does apply a mechanical advantage. The torque input is greater than the torque output of the converter while it's slipping - typically up to double the torque at stall. It's not very efficient, but it's much more efficient than just slipping.
@@badavisuf I'm trying to differentiate between 'slip' and 'converter'. I think this is a distinction without a difference. A torque converter IS a slip device. It doesn't make extra torque. It only allows the engine to run at an RPM at a point where the torque of said engine is at its greatest or near it. Still missing in the PowerGlide is the mechanical advantage of different gear ratios as suggested above.
@@sonicdewd It doesn't *just* slip to max engine torque. Torque output is higher than the input. The fluid is routed in a cool way through a stator so that it gets multiplied. I think Jason has another video on it. Also Wikipedia.
Super late reponse but a lot of Toyota's CVT vehicles also have a first gear for getting off the line before "shifting" to the variable gearing. Any vehicles with the "direct-shift" K120 CVTs have this quirk.
I rather like the CVT in my Swift, and I think it actually does do the smooth curve thing rather than mimicking gearshifts. Definitely feels smooth to me. From the driver's perspective, the RPM is determined by throttle input and the ratio just adjusts to match that to the speed you're going. Hence the engine note does vary quite a lot - it likes to sit around 1000-2000, but if I put my foot down then it'll jump up to about 5500 RPM. It's honestly just nice to drive.
I heard CVTs were bad, I drove one in a rental car on my vacation and it was very dull experience, BUT it was a very smooth ride and little to no noise. I would say if I was an old man winters and wanted to just chill CVTs are sick
Pretty much my experience. CVTs are good transmissions in theory. My problem is I just don't trust them yet. Planetary autos, automated manuals, and manual transmissions are known entities at this point, CVTs are relatively new to the consumer market.
They've not been available as long as a standard auto or manual. DCTs have a ton of racing pedigree. CVTs are known to have problems in high torque applications, and at this point are pretty much only used in consumer economy cars. I'm sure they will be more or less fine, but I'll still wait and let other consumers purchase the first few generations.
The STI doesn't have a CVT, and the WRX isn't exactly a powerhouse of a car. That said, (according to COBB) the WRX with a CVT is down 30 HP compared to the 6MT and has different head castings. Has Subaru put lower power into the CVT car so it can hold together? Maybe, and the 0-60 times bear that out.
The most impressive thing about this is that you can do it all in one take (and without stuttering!!) I took grade 11/12 physics so this brought back some memories and I was able to follow but I could never explain it so flawlessly.
+milattx I think people prefer shifts because as you go through gears you feel an accel/deceleration pattern that people emotionally connect to speed, but the truth is that feeling as at a cost on performance.
There's a good number of people asking about how the Koenigsegg Regera's transmission works. Just wanted to let those folks know I've made a video on it! Have a great day everyone! :) th-cam.com/video/naRY3knqFYU/w-d-xo.html
Interesting as always. In a future vid could you please do a in-depth on how unsprung weight effects the cars proformance and torque as well as the benefits and disadvantages.
Would putting a CVT in consumer cars also reduce price? With a CVT would it also remove the "jerkiness" of shifting? If it does, I don't understand why people wouldn't want one, they're just living in the past.
Nice overview, especially the explanation of torque vs power. I think understanding gearing is the key to understanding the difference between power and torque. Btw how do CVTs shape up in terms of power loss(friction) compared to manuals? Also a cool topic to cover would be how lubrication in an engine works. I know the oil pump pumps oil from the bottom of the pan up to the cylinder head and some engines have jets to cool the pistons, but I'd like to know through what path the oil travels exactly and how it affects oil pressure and engine wear.
I “invented” the cvt in my history notebook while doodling instead of studying a few decades ago. I was convinced it would be best to enable a driver to manually control the rpms. my vision was for the ‘infinite ratio drive” to be manually controlled with a “shifter” that was similar to a boat throttle. The driver would move the arm forward or back to control rpm, or while accelerating, gradually move the arm to keep the rpms constant as speed increased. It involved fluted cones. Anyway, I’ve seen many over the years but unfortunately durability and efficiency have been issues. I’m still convinced it will ultimately be dominant. I hope I see that before I die.
I have a Nissan Murano with a CVT. Terrific! It always has the correct ratio vs torque and RPM. There is no problem if being in between the best gear ratio. I like the smoothness of the transmission no matter what speed or torque change is occurring. The vehicle has some shift positions to simulate fixed gears. This allows operation at fixed ratios as if it was a gear transmission. This feature is great for situations where a trailer is being towed and the driver would prefer fixed torque. Also simulation of gears allows for compression when going down hill, or wanting to use the engine to slow the vehicle. The only drawback I found is if the driver tromps down on the accelerator the CVT takes maybe a few milliseconds longer to get in to the proper ratio for best torque to accelerate. I am being very critical here. Since I am not racing my vehicle this is not an important concern for me. My preference is to keep using vehicles with CVT over a standard automatic transmission. A manual transmission with a clutch would be the exception, but for city driving I would prefer a CVT.
I have a Nissan Murano and I HATE the CVT. It never seems to be in the right RPM. When that happens, I just push the shifter handle to the right and BAM! The car accelerates quickly like a rocket, but the RPM's are way too high. I'm more of a manual transmission fan anyway.
Again the problem is it is a Nissan, my Jeep has a cvt and after you get used to the fact it doesn't have the gear shift feeling, which is nothing more than a mental thing, it is great. It is always in the optimal mode for acceleration, cruising and braking. Engine braking is progressive so you have less brake pedal effort on normal braking and that extends brake pad life.
I've had a rental Juke for over a week now coming from a 5-spd Altima. I actually think you've figured out the right way to drive with a CVT. Instead of just choosing one mode or the other, use D or +/- situationally all the time. When I first got it, I was driving it more like an automanual choosing to see which mode I preferred. Now, I vary it depending on what the conditions are. It was strange seeing how slow it felt in D, but I'd look down an realize I was at a higher speed than I realized. I think the high RPM sensation might have to do with the way Nissan has programmed the "gear" steps. Of course the highest ratio seems MUCH higher than usual in a geared transmission, so maybe that has something to do with it. Does it have an I-4 or V-6? Have you pushing the pedal down further while in D to get the Murano to step down faster instead of +/-?
@Meme Man yes nothing that makes power, I can’t stand when I see companies continuing to use CVT’s when all they do is fail and fail badly and quickly.
I like the CVT in my Crosstrek. It works, the car doesn't lag behind when it needs to shift. It's great. They do have manual shifting in it as well which is really nice for when you need power ASAP. Just tap the downshift paddle and it downshifts and then goes back to normal CVT operation seconds later. I'd definitely take it over any auto transmission any day. A manual transmission to me is something for fun just to get that feeling of smashing in the clutch and changing gears. Other than that I know it's just a novelty.
I know for a fact my stock getrag f23 5 speed manual transmission could handle 3-4x the amount of power your cvt transmission would hold. Not just a novelty item but a must have in some situations.
there is no shift in a cvt, you need to find out how cvts work and then you will be disgusted by the cvts that upshift like automatics. cvts are like a band that you pull and that band doesnt have only 5 different pulled positions so instead of changing gears cvts should have something like pulled percentage like your volume nob , with the + shift you go to the highest "gear" which is 100 and with - you reach 0 the lowest "gear", paddle shifters on cvts should act like volume nobs, shitty audio players offer you 10 different positions while the good quality ones offer 1000 different positions so the same goes for cvts the race car cvts will have 1000 different positions while your maxima is trying to be an automatic but should have 50 different positions.
If F1 used CVTs then it'd probably be disastrous because imagine today's 1.6L Turbocharged F1 cars revving at 15k RPM for almost the entirety of the race. It's too risky
@@anonunknown933 in this case i agree that it would be has, because them disallowing CVTs is an ongoing action. if i got a car a couple years ago and i still have it, you wouldnt say "he had that car a couple years ago"
To everyone complaining about the reliability of CVTs, Im guessing you dont own a Ford Focus with the Powershift transmission. These DCTs are notoriously hard on clutches. We had so many of them coming through the shop that we had to buy the tools needed to replace the clutches in them instead of sending them out to the Ford dealer or a trans shop. They would shudder so badly it was hard to drive, many times just outside warranty limits. In fact the majority of trans failures were conventional automatics, though we did see some Nissan CVTs come through the shop needing replacement. My experience with CVTs, as a 30 year auto mechanic, is that they are just as reliable as any other transmission, and WITH PROPER MAINTINENCE can last just as long as any other trans. Throw in the fuel economy improvement and I wouldnt buy another car that didnt have either a CVT or manual transmission. Most problems I see are from owners who did not properly maintain their vehicles, then saw the high cost of getting it back on the road and decided to blame the manufacturer.
@@edgaryzen4925 I was shocked at the condition of some of the cars coming into our shop. Brakes don't just suddenly eat into the cooling vanes of a brake rotor, valve cover gaskets don't suddenly leak 5 qts of oil out of them, and expecting an automatic transmission to last 150,000 miles with 0 attention is just not smart. Many people were driving around with obvious problem after problem until the vehicle simply would not move further, then wanted to complain when they get a $5,000 estimate. If you had addressed these issues 40,000 miles ago its likely the estimate would have been 75% cheaper.
CVTs are all well and good, but they are woefully inefficient (I'm one of those race car driver guys he talks about). Yes, in a perfect world of mathematics, CVTs do produce a better application of force. Where they fall down though, is when you add physics into the equation. CVTs are made to hold the engine at a steady RPM at variable speeds. It's sounds like magic, but on consumer grade cars, they're nice for fuel economy. Now, where they fall off is during aggressive driving... and track cars are all aggressive, all the time. Take a Corolla out and put it on the interstate at 75mph. Now, put it into passing gear. There is a a long, noticable lag in the downshift procedure. Now, slam on the brakes and accelerate hard in quick succession. You can do that a few times until the transmission gets locked in a "low" ratio and robs you of all power until it normalized. In a race car, this is unacceptable since cornering requires hard braking and quick, hard acceleration 30-50 times per lap on some courses. The CVTs also produce a tremendous amount of heat in comparison to standard transmissions work. This creates an entirely different set of problems for performance engines which can operate 50 or more degrees hotter than a consumer grade engine. Lastly, you also can't really tow with them because adding additional weight to the vehicle will cause the CVT to keep the vehicle in "low" gear and ultimately overheat itself or the engine... or both.
As far as the corolla goes, that's only a matter of the computer telling the CVT what ratio to use. The CVT being in a low ratio after deceleration isn't something intrinsic to the CVT, just a lack of sporty programming. Try a Nissan with 'sport mode' or a WRX CVT and you'll find that after deceleration, an aggressive ratio is waiting for you to smash the pedal. Remember, CVTs are 100% computer controlled using inputs like load sensors, speed sensors, gas pedal position sensors (they're drive-by-wire) and translating the available power and power demand into an effective RPM and ratio combination. I don't know enough about the thermal properties, but since it relies on friction, I could see it making more heat. As for towing, well that's just a bad idea. If the engine can produce enough torque and the CVT can handle the load, it'll be fine. Nothing about the CVT itself is going to lock it to a 'low gear', but given how they work, towing would just put too much stress on it unless it was designed to handle the load.
There is friction and heat. However, it's more or less about the infancy of the tech in relation to materials and its ability to disperse heat. Look how far normal clutches have come over time. Same goes for oils. CVTs in their current state are still relatively new and have a lot of challenges. Eventually, someone will take up the banner and solve the problems. Well.... they kind of have in Nissan making everything have one. With that said, they chose a different trans for the GTR and electric power in hybrids is supplanting that need to have something "shiftless". For a commuter or weekend warrior... it's perfect. For the other 5%, well, it'll get there eventually.
You are correct, CVTs aren't good at performance driving. I've watched F440/500 formula cars autocross with their 2-cycle snowmobile engines and CVTs. They must keep their RPMs up thru the corners not lifting off the gas.
Yes, agree totally. In the UK I have driven and owned manual-boxed cars, robotic boxed cars (i.e. Manual gearbox with electronically controlled change), automatic and CVT. Without question, the CVT box is the one I would actively avoid as to use they are rubbish. Hateful things! And trying to hill-start with a CVT is often a nightmare of screaming engine and fighting rolling backwards. And they are noisy - they maintain this booming whine as they try to maintain their constant velocity. I'm sure they would be fine in a milk float but in a car they are hateful things.
I had a CVT about 15 years ago and loved it. It accelerated so smoothly. It was deceptive because the engine doesn't rev and shift. Before you knew it you were flying! Where it was really nice was towing a trailer through the mountains. You didn't get that hard shift like with other automatics. It was smooth and confident. We did not have reliability problems. But I'd like some hard data rather than individual anecdotes. I'd get one again.
The first CVT I drove was my mom’s 06 or so Altima. I floored it, and was immediately impressed with how it accelerated. Today, my wife drives a 2019 Outlander Sport with a CVT, that performs well. If someone were to actually develop this transmission to take power, it would really be a game changer.
+Kwabena Asamoah actually, if dude is from the UK, learnt I'd an acceptable way of expressing gaining knowledge in the past tense (and, therefore, actually in American English as well, though we tend to use the suffix -ed over -t in the past tense). The more you know!
@HiWetcam Diamonds do exactly that. You don't have a prop lever anymore, it's all FADEC'd. You simply push forward for more power, the FADEC figures out the optimum engine rpm and sets that. So at cruise my DA40 typically uses around 2050 rpm, but if I firewall it, it goes to 2400 rpm. Funnily enough, it also gives you the ability to use the prop as a speedbrake. When I pull the engine to hard idle, the rpm suddenly goes from 1800 rpm to 2200 rpm, but not by increasing fuel burn. The FADEC recognizes that you want to decelerate, so it shuts off fuel injection and turns the prop to flat pitch to use the oncoming air to turn it at high rpm, maximizing propeller drag. With this effect in play, you can absolutely dive-bomb it on approach.
Had a 2011 Mitsubishi LancerGT with cvt and paddle “shifters” to help simulate actual shifting. Had absolutely ZERO issues with the car. The wife loved the fully auto mode, while I loved the ability to use the paddle shifters to select my own “gear” to accelerate in. I would have no problem buying another one, as long as it had the ability to select between fully auto or manual selection like that one did. Loved it!
I've owned manuals, CVTs, and autos. CVTs set up in a performance in a vehicle (ie snowmobiles or atv/utvs) are insanely fast. I remember my friend who owned sports bikes for years bought his first sled (670 2 stroke cvt) having the expectation it wouldn't be able to compete with his GSX-R nearly pissed his pants when he punched the throttle for the first time. He had the biggest grin I've ever seen after his first drive. Call CVTs soulless, but I like having that power "right there" all the time.
Well, I got 43 MPG in the Civic vs 37 MPG in the Elantra in the same daioly commuting and with very similar engines between the 2 cars. The Civic is CVT, the Elantra is traditional Auto.
It's not that they're soulless, it's that the drone makes me literally want to kill myself. It's the same reason I hate electric cars (road drone from no exhaust note and also the fact that it's electric) even though in reality Teslas are badass, if expensive.
Yep. This video is correct. He completely left out the fact that if you adjust your CVT to maintain the engine rpm at the torque peak instead of the horsepower peak, the engine will get the best power out for fuel in. You also have to account for reducing the RPM to as minimal as your engine can be smooth at steady state speeds. For instance. My Dodge Pickup with the Diesel engine has the torque peak at 1600 RPM But if I drive at 55 mph which is 1600 rpm in 6th gear (manual trans) I get about 22 mpg. If I drive in 5th gear, 2400 rpm, my fuel mileage drops precipitously. If I drive at 35 mph in 6th, the engine is turning about 1,000 rpm and still gets better fuel mpg than if I'm in 5th gear. Only slowing below that speed actually requires me to downshift so that the engine is not lugging. So the video is correct for acceleration but not for fuel mileage. The CVT will only maximize fuel mileage if it's set up to cruise at the lowest rpm the engine can handle. The reason that corvette has 6 gears instead of 4 as used to be the most, is to keep it nearer the point of maximum power in the power band. The CVT may actually be more efficient than a manual as well for maximum fuel mileage but whoever is writing the software to control it had better take all that into account. My Suzuki Burgman had a CVT and it wasn't optimized. It always used higher rpm than the engine needed, especially when at a relatively low speed, 30 mph vs 50 or anything like that. I'll stick to my manual transmission, so I can control the gear selection rather than an improperly programed computer or spring and clutch set.
I'm really thankful that Mitsubishi in the Lancer decided to only go with the stepped gears mode in the higher end GT models, and only when in "manual" mode with the appropriate shifter with +/- on it. the ES, the literal bottom line model, just has a "drive" and a "low" gear. this is hands down the best CVT configuration you can get in these cars if you go with a CVT, and you should avoid the type with the +/- on it for reasons outlined in this video. if you have one with a +/- shifter, swapping to the "low" style shifter is literally just plug and play, as the TCU is programmed with both modes and uses the shifter to determine if it needs to have a simulated gear mode or not. the "low" style shifter is also usually easy to find and fairly cheap, as most people consider it the inferior shifter (which is not the case!) "drive" focuses on peak fuel economy, and tries to keep the RPMs as low as possible for a given throttle position to keep your fuel economy high. "low" on the other hand does the opposite and tries to keep your car at its highest RPM for a given throttle position so that way you can accelerate and decelerate as quickly as possible. the result is the best of both worlds of fuel economy and peak engine power selectable at will. when driven properly you *do* end up shifting a a fair amount between "drive" and "low" because they're basically a selector between "do I want high or low RPM?". being effective with a Lancer CVT means mastering which gear to be in and when exactly to shift between them and when to stay in one or the other. it's a thing of beauty! the CVT comes with some downsides (like frequent and expensive service intervals, especially with hard driving) but IMO the CVT Lancer ES is something everyone should experience at least once. it's an experience you can't get elsewhere and is the CVT experience in a car in its peak form! - β
Make sense. Thank you. LOW HP reliable engine such(as the 3A92 as it been around for 20 years) and Mitsubishi Mirage do couple very well! The Mirage’s CVT for model year 2014-15 used to be just D and B. Since 2017+ model year, it is D, Ds and L.
Oh god really? I would have been too busy walking to the 711,(not the closest one), down the middle of the road swearing at traffic to get some peanut m and m’s barefoot without a shirt on and then waking up remembering nothing wondering why my bed was full of m and m’s and wondering why my girlfriend had the shits with me lol.
Anybody got anything for me ? Just bought a 2014 Nissan Maxima just turned 30,000 Miles. So far i Love it, took a little while to get used to the CVT, think it's a Great idea for a everyday driving car, for good fuel mileage, Not a Good design for any type of Performance Driving. Maybe i need to start taking a little more Narcotics, Like You Guys said.
Said this in the short, repeating it here: hybrids that have an eCVT actually have a system that's better than a belt-and-pulley CVT simply by virtue of not being limited by potential belt slip. eCVTs are typically a planetary geared system, where you have the engine on the sun gear, an electric motor on the planet gears, and then the output of the two combined into a ring gear. Varying the speed of the electric motor so it either partially counters the input of the engine or adds onto the input of the engine results in varying the effective gear ratio, and it doesn't take that much electricity because, as it's doing this, at the other end of the common power split gear is a much beefier electric motor that not only can propel the vehicle on its own (so the engine gets shut off at low speeds for the hybrid's EV mode) but it also acts as a generator to facilitate both regenerative braking and supplying the electrical power needed when the smaller electric motor is working against the engine to produce a higher gear ratio.
CVT's are mainly used in cars to conserve fuel (save money), yet these CVT's don't tend to last nearly as long as a regular transmission. The money saved on fuel, won't replace a 5,000 dollar CVT. Apparently they cost the auto makers less, but is not reflected in the price of the car.
You could be correct, Idk to what degree without scientific tests. A big chunk of that is labor taking it out and putting it back. Would be great if you could replace a clutch or CVT belts almost as easily as replacing a serpentine accessory belt. That would mean a little extra space and a little weight I think, but you would really think it was worth it when it needs service. Had to rebuild auto trans in 98 Accord 4 cyl at just 50K miles. You have to baby those clutches too. No trailers over 1000 lbs, no aggressive driving. I feel the same way about timing belts they could definitely make those easier to get to simply by making a point of it. There is no real gain by packing the engine tranny/ area to within an inch or 2 of it's capacity. You can design access in with no penalties if you design it through more. But a rebuild on a CVT should be no more than about 2-3k at the most. Take it to dealership yeah they will gouge. So you are right, one failure can cancel years of gains. But my point is all the other tranny types including manual clutches can need service prematurely too. Kinda depends on the model, it's vulnerabilities, and you driving style/uses I guess. If you babied some CVTs they might go really long too. I would try one for my next car if they were still doing them and if hybrids weren't coming that use same idea. Alternator/battery/motor acts as CVT there, engine can run constant higher RPM at peak efficiency to supply electricity.
also CVTs are limited to the friction that their belts have. its a lot easier pushing hundreds of ft/lbs of torque through steel gears than a rubber belt.
I have driven my CVT powered car for 8 years and can say that a CVT acts like a turbo charger except that the boost is at low speeds rather than high speeds. If I step hard on the accelerator, the motor revs as high as I want within a second or 2 (maximum power) and the variable transmission changes gradually changes as I accelerate from 0 to over 60 mph without changing the revs at all. There are also no jerky shifts along the way. Unlike a turbo charger, this transmission can also optimize the RPM’s to save fuel and still give sufficient power when going up hills etc. Bottom line is power and performance when you want it and gas savings all the rest of the time. My car has driven 168,000 miles or 280,000 km since I bought it new and the CVT is still going strong. This is technology that has to be seen to be believed. I still feel the magic from my 3.5 liter motor combined with a CVT, even after 8 years. Thanks Nissan.
Biggest issue I’ve seen is reliability with CVT during the early stages of manufacturing. Nissan struggled hard to provide a reliable transmission. The technology has increased so has the reliability.
Nate Bryant mine is a 2010 altima I bought 4-5 years ago. Surprised it’s last me this long cause I beat the crap out of it. Number one enemy for cvts is heat. Changing the fluid and filter every 50-70k miles is what has helped mine stay alive. It used to whine after 2 hours of driving in Texas heat but been quiet ever since i changed the fluid
@@saisr1 It is very sad, I went from loving and excelling at math, and forcing teachers to teach 2 classes simultaneously in the same room because there weren't any other students who advanced with me to warrant making another class (country school problems), to hating math. I was getting sick every 3 weeks and missed so much the school forced me to leave rather than qualify finishing that year, I never rebounded from it, only gotten worse. Myalgic Encephalitis claimed all my mental executive function and memory and I have never been good at even basic math again. But what isn't sad is that it forced me to more deeply appreciate the beauty and aesthetic of everything.
@@LastAphelion well hopefully you have found something that you can enjoy. My BS was in mathematics. I haven't barely touched it for the last 18 years so I don't recall much of it, but I can still follow along when people explain things in mathematical terms. I do remember algebra halfway decently so this was ok. But all the upper division stuff I did, very little is retained. I often wonder how far I could have gotten with it had I gone to grad school for math. But the BS seemed about at my limit when I finished up. Everyone else around me in the math department were all way better at it (with the exception of the math education students who were only going to teach HS level math anyway). Everyone but me from my graduating class was going on to a masters or PhD program. Some of those classes were down right awful. Topoly for example. 8 students including me. The other 7 were either headed to grad school or were already enrolled and then me. With my head spinning.
CVT has been in atv's for over 20 years and have proven to be pretty awesome and getting better every year. Side by sides are so fast because they can run at the perfect rpm all the time. They've proven to be durable and reliable too. In fact, so durable and reliable that Yamaha has a 10 year belt warranty
Though guy's are saying below that CVTs were being used in F1... I thought one of the limitations of CVT is that it is difficult to build one that can manage the stress of a high output motor and remain reliable.
FadeKing I don't know about any lap turned except in the wet, but F1 does indeed ban any real tech. It makes me laugh to hear someone say that F1 is about high technology....
I have a 2010 Nissan Maxima Sport Package, it has a CVT, and it hauls ass to say the least, not a super car or exotic, but for your "average" car it a beauty🙏🏼 I drive the hell out of it and never have problems with any components. I love it
I had a 2010 maxima too, done 210,000 kms and sold it absolutely no major issues at all. Missed the car so much I got a 2012. Currently 163,000 kms super reliable
As a mechanic when the cvt first came out I was replacing around 3 a week lol. The belt driven one would have the belt come completely apart and the chain driven one would slip and scorch the chain and the main bearing would come apart too 🤷♂️
@@fnvideos4233 yeah and some kias that have cvt now. But Kia warranty sucks. I got about 7 to 8 hours for a Nissan cvt, kia is a straight 3 hours warranty 🤦♂️
One cannot assign blame to a concept. I did not say the free market was a problem. I said the consumer was the problem with the free market. You should read what I said before going on a tirade. Just a life pro tip for you.
Consumers are also the strongest link in the free market. It's hard to saw what type of car was struggling to have adoption of the original CVT designs (e.g. sports cars) as some people may prefer a certain feel with the type of car. I'm under the impression that the vast majority of vehicle owners prefer fuel economy over engine sound/feel. As this video shows CVT are more practical for fuel economy, many consumers on that side would then likely prefer CVT transmissions. The consumer base wanting more fuel efficient cars (as one of their top characteristics) would likely choose a CVT car if better fuel economy despite stepless gears, over stepped gears. Again, I think it may have been car enthusiasts that the original CVT didn't appeal to. Consumers have been demanding want more fuel efficient cars..and the development of CVT may very well have come from the market forces to create a product to meet that need to stay above competition.
This is why future electric cars will outperform anything we experience yet. No gears, no complexity, no drops in traction just pure performance (assuming an intelligent traction control software).
Really poor range especially on lighter weight vehicle like scooters and motorbikes I am assuming their torque always overcomes the inertia needed to start the bike/car moving so why no CVTs to adjust the amount of Revs actually delivered to the rear wheel to improve range befuddles me.
Electric vehicles produce more pollution to manufacture, and operate than gasoline vehicles. FACT. Also they are impractical until they can find a way to produce electricity onboard, and not have to rely on hundreds of pounds of environmentally polluting batteries.
Not fact. EVs produce more pollution to manufacture, but they don't produce any pollution driving. And if you charge from solar panels, that's NO POLLUTION at all. Batteries don't pollute. They only need mining lithium and cobalt. When batteries start being recycled, then less lithium and cobalt will be mined. If you can charge at home, EVs are MUCH MORE CONVENIENT AND PRACTICAL. Up to 600 km every day and dirt cheap. Watch "Range anxiety is a gas car thing, not a Tesla thing" on Tech of tech channel.
@@ryotaryuu initially, yes. But they achieve way higher mileages. Tesla is close to getting their batteries to last a million miles. You'd need to build at least three ice cars to cover that. And we are just starting. Electric cars went viable only recently, they will get mich more efficient in the future.
"I wouldnt want constant RPM" "Why?" "Because i want my engine to spit fire when i shift" Unless your car is modded so that your engine spits fire (mainly exhaust mods) then you really shouldnt care if your car is at a constant rpm
@@tbros9995 depends on your buffer. your car has loads to buff the sound anyways. so even if you delete your cats and muff, your cabin has enough to buff out the sounds. Plus you'd be playing music on top of that. It does not matter if you care about the constant buzz since it would be the same impact as cruising in the highway at a constant speed. As for stop and go, that will break your monotonous noise.
Plus I believe if it's at a constant rpm it has to mean less engine wear. Every car I have owned has been manual, but even I start seeing the benefits of cvt as they advance and become reliable
@fuckoffgoogle wrong, the torque limitation only applies to belt driven cvts that slip at high torque. there are other transmission techniques that have the same effect as a cvt, such as transmitting the power electrically in a serial hybrid setup, or whatever toyota does in the prius which does not use a belt driven cvt. People don't like CVTs because they think the engine droning at a constant rpm is boring, but whether you want the best power or the best fuel efficiency, cvts are the way to go.
Most performance cars don't use CVTs because "performance cars" are not 100% performance oriented, because your average fast car buyer thinks gears are more fun. But you know what vehicle does use a cvt setup? Diesel trains. Diesel locomotives use an electric transmission in which you have a diesel generator sending power to electric motors that move the train, and that is essentially a CVT because the diesel engine is always running at optimal efficiency for the power demands, and diesel locomotives regularly deliver power in excess of 1000 hp.
That's not true. CVT's can be engineered to be quite robust, but no one uses them in performance cars because they know their customers. The real reason is because the average car buyer likes to see the RPM needle go up and down, and that's because the race cars that sports cars emulate have needles that go up and down. At the same time, they're not used in racing because that means spending a ton of money on development, and they might only be marginally faster than existing transmissions. If it wouldn't result in a big enough gain to win, I doubt many racing teams would spend the time to develop. That is, if it would even be legal. It might create a massive advantage in another way. If all the transmission has to do is keep up with engine output, the driver doesn't have to do much in the way of thinking about the best gear to be in.
Whats so hard to understand? A cvt allows you to always run the engine at peak power and/or efficiency for a given throttle setting by adjusting gear ratios between engine and wheels, thus allowing the engine to always run at optimal rpm. A serial hybrid setup allows you to always run the engine at peak power and/or efficiency for a given throttle setting by replacing the mechanical link between engine and wheels with an electrical link, thus freeing the engine to always run at optimal rpm. In fact, the 2014+ Honda Accord hybrids which basically uses a serial hybrid setup for speeds 0-40, calls its transmission an "e-cvt" as in electric cvt as in its called a cvt because it has the same goddam effect as a cvt. And you know what, the Tesla Model S is powered by 70lb watermelon sized motors producing 360hp each. Stick four of those motors in a car and hook it up to your favorite V12, and the result is a supercar with all the instant torque of electric cars, all the power and range of a gas car, and no complex gear-stepping transmission to speak of.
Well since if you floor it the gearbox will hold it somewhere near the rev limiter continuously, producing max power, it will also increase fuel consuption
Good question! My guess as it's written by "Randy Beikmann, PhD" is that it is American (published by an Americna publisher), and uses American units. (Amazon doesn't seem to have "look inside this book" for it ... also it's nearly $60). - Although I just found a review that states "You will have to live with two sets of units and a few other physics/automobile language idiosyncrasies, but that does not present much of a problem."
academically STEM majors (assuming the author is a physicist) metric is standard not imperial, even in America. I doubt you would have any trouble either way though because conversion is easy and is likely addressed in the book. I am an engineering student in the U.S. all physics, chemistry, etc. is in metric... but again, conversion is easy either way anyway.
I just looked at buying a taurus x about 8 months ago. I called a friend at the ford dealer in the shop for his thoughts on it. He said well it came with 2 different transmissions a cvt or a 6 speed. He said you do not want the cvt because no one works on them and ford doesnt have parts for them let alone a new in the box replacement. You will be limited to junk yard only if it goes out. It had the 6 speed but i didnt buy it after we ran the VIN number. Also a friend up in Detroit had a jeep with one in it that started going out on him. They rebuilt it and about 6 or 7 months later that one went out. It was his wifes vehicle and she is not an aggressive driver.
I love my CVT bike, but wish it could sit at lower RPM when I'm moving slowly and don't need that power, so it would be quieter. With my geared bike I have control over that.
Good basic explanation on the physics of CVT. The road load and driving force management side regarding adjustability and linearity is also a big plus for CVT. High power applications are limited by cvt belt and pulleys production costs and overall efficiency from friction and oil pump losses.
@@haha71687 8th grade math, combined with 11th grade physics, but yeah, this is pretty tame stuff for anybody who's taken even a casual interest in the physics of engines.
As a final year Mech Eng student - they really are simple. But even while learning this stuff we struggle to make all the connections. Most problems are fairly simple to solve once you have ALL the tools and equations to hand, and don't make any mistakes or detours on the way...
I feel smarter every time I watch your videos. I own a 2020 Kia Soul x-line with their IVT (Intelligent Variable Transmission) and it’s fantastic. Going up hill it doesn’t search for gears because there aren’t any! If I’m caught in rush hour traffic I use the automatic shut off for fuel economy, other than that I leave it off. No issues. Goes to the dealership for all service, recalls or software updates. Not a issue & I’m at 27,000 miles. 🇺🇸
Love my Civic CVT. I have gotten 5.2 liters per 100 km on the highway (45 mpg). I can ride my motorcycle if I want to shift, but in stop-and-go traffic I want my CVT.
That's an example that truly doesn't make much sense, and I'll hand it to ya. The manual WRX is lighter, faster, cheaper, get's better mpg, and obviously is more engaging.
That's not a race car. It's a rally car, of course it should have a manual. Track times don't matter. I'd be interested to see a CVT on a Ferrari though.
I have a 2016 Nissan Maxima SV with 100k miles, and mostly highway since i purchased it last year with 35k miles on it. Again majority highway miles, i get on average 33 mpg highway, 29.3 mpg overall. I've done all my maintenance to the T and I'm loving it. Don't get me wrong, I'm still hoping it'll survive a couple of more years now that I'm not going to be driving no where near as much as I use to, but i can say that at least in the new Maxima's, if you take care if the car, and not in a city environment all of the time, it's a fun car to drive and stays smooth.
The mechanical CVT was invented in 1490 and has been used in cars since the late 1800s. They are theoretically the perfect match for internal combustion engines. Internal combustion engines of all types are most efficient when pressures are the highest, which is near maximum torque. As you pointed out, maximum acceleration occurs at maximum horsepower, thus the vehicle could always in the right gear with a CVT, regardless of the required output shaft speed. The main reasons they are not in widespread use are: 1. The high-wear and less reliability of the variable drive system. 2. The variable drive system is inefficient in and of itself. The one most commonly used is the double-pulley system because it is lighter and less expensive. The reason the desire to pursue CVTs in the automotive world has faded recently is the advent of the 6+ speed electronic automatics, where you get the torque multiplication of a torque converter on the low end, the efficiency of gears over the remainder of the range, plus maintaining the engine at an RPM that results in overall greater efficiency than a CVT. Additionally, the advantages of the CVT with regard to simplicity are more than offset by the requirements for more expensive components. Stepped cones and chains have been tried to overcome some of these inefficiencies but they had too many reliability issues. While Nissan has broken a barrier by making a semi-reliable CVT for a 3.5 liter engine, class action suits are not in short supply. Simply put, CVTs have not been cost effective, have given those who implement them a bad name and massively expensive to warranty, and now no longer are the most efficient to be used in cars.
I think high end sports cars should be offered with CVTs with options to either run it in a "DCT emulator" mode where it "shifts gears" and a "sport mode" where it always sits at max power.
I think that is actualy a good plan, I don't see why it wouldn't be possible for there only have to be two presets in the CVT's computer. (don't know if it has its own computer or that it runs on the ECU)
mr id Yeah I mean I won't pretend to be some expert on automatic transmissions, let alone CVTs. But I feel like it could be a viable option, especially in supercars or high end sports cars, they should be able to make it work. Then people could get the classic sound while driving on the streets and the fastest possible track times when they'd like.
uptorest High amounts of torque wouldn't work with the current CVTs, but they could make CVTs designed for more powerful engines. They just aren't because people don't want them even though they would make cars faster.
Problem is that for high performance such a transmission would get prohibitively expensive because of low tolerances and short maintenance intervals and prohibitively heavy. I know the terminology only in German so please excuse me if I sound like I had a stroke. CVTs in cars work with a conveyor chain, basically not unlike a bike chain except that instead of a chain between two gears you have a chain between two pairs of... errh... Kind of massive discs where one side tapers to a point. And those are spinning at high speeds. Now imagine a bike chain that can transport 600+ lbft of torque between those. Now imagine that this monster of a chain moves at 8000r/m directly below your butt. Imagine the vibration alone. Imagine what happens if the chain might rip. Doing this kind of transmission to transport such high torques is just not worth it. Remember: "It seems that perfection is attained, not when there is nothing more to add, but when there is nothing more to take away." - Antoine de Saint-Exupéry
Nice! Really well explained. Interesting how the physical control of the transmission is also an emotional connection with the car/truck. Hearing and feeling the engine to decide when to shift is a feedback loop that rewards the driver. That may be half the argument against CVTs. CVTs could be made to remove and replace, instead of repair/maybe.
Does the transmission have any effect on engine longevity? I always thought that an engine with a CVT might last longer due to running more consistent RPM with smoother application of load on the engine as well as being stall proof
there was a CVT invented by George Constantinescu, that made it into a car in 1923 some details here www.rexresearch.com/constran/1constran.htm got bought out by general motors, and the idea disappeared into obscurity
DAF called it the variomatic, 1950's up to when Volvo bought the company (last car which had it was the Volvo 340, in the late seventies-early eighties)
My DAF 44 would go as fast backwards as forwards, and out accelerate cars with an engine twice the size in town. Back in the late 1970's the fastest production automatic car in the world was a DAF 66 in rally trim, at a mere 130 mph, from a 1400 cc engine. The only thing better for driving than a CVT is Electric drive. Gears are for the 20th century.
CVT is, by principle, the only way any kind of automated transmission should work. Too bad that almost any practical application of CVT in cars has shown huge issues with reliability over the last years :/
Not to mention all the major parts wearing together and rebuilds not yet a feasible option in most areas, so if it fails you generally have to get a new unit. If it weren't for that I'd probably have a CVT in my garage. Plus the cost... a little CVT for a 2.0L non-turbo Subaru retails about $9100. Compare that to a Tundra's hefty 6-speed Aisin AB60 automatic transmission that new-in-crate from Toyota has an MSRP of about $4400, less than half the cost of the little Subie transmission, and it's not because Toyota wants to sell parts cheaper. Anyone who's ever owned a Toyota knows they don't. If they did they wouldn't list the same truck's 3UR engine at $23k.
You need to service them but you must use the dealer fluid no substitutes and a quality filter name brand aftermarket no china or best bet dealer. Don't skimp on this service and do at least once a year. I have found that not servicing and not proper fluid is the cause for most of the failures at least with the toyotas anyway. 47 y.o. Trans. Tech. and 2014 corolla s owner with CVT paddle shift.
If they make the belt easy to remove/replace like a timing belt I would totally go for a CVT but until I am confident that at any given moment my transmission won't blow and/or it blowing wouldn't put me back more than a hundred dollars and an afternoon it's a no go.
+Andy hoff Don't be mad because you can't tell the differece between sex and gender. The definition of either hasn't changed. The interpretation of the latter has advanced, which it can freely do since gender has always been perceived, and sex is what is assigned by genitalia. I'm sorry you're incapable of advancing with modern society, but overall, that's not my problem. It's also not Engineering Explained's problem. Stop trying to make it ours.
I have been driving SUVs with CVTs since 2005. I have not had any problems with these. I do buy the extended warranty as assurance in case if I have a problem. I like how the CVT works and performs for the type of driving I do. I must admit that at certain speeds there is a bit of lag or delay of maybe a 1/10 of a second or so for response if rapid acceleration is demanded. Once the transmission gets to the proper ratio for the power demand the acceleration and performance is impressive. It is true a CVT can be about 15% more efficient for fuel economy and for performance. Manufactures are starting to use more CVTs in cars except for where a manual shift transmission is required or demanded. Heavy duty trucks and high performance vehicles are best with a heavy duty transmission in manual or automatic type.
Thanks for the video. I shall read up more, however I was under the impression that we cannot currently build an efficient CVT that can cope with high power outputs. I drive a stock engine/gearbox Toyota 86 at time attack events. I would love nothing more than for the engine RPM to be at peak all the time; it is always a compromise when cornering.
I've loved CVT's for their theoretical perfection! They have solved the gear problem, and it is CVT. I love it aesthetically, I love the smoothness and efficiency, factors I have tried to optimize with manual transmission, but the CVT does it SMOOOOOOTHly and that gives me driving pleasure!
It would be really helpful in understanding more if you incorporate animation into your videos, side by side explaining the whole concept. Not speaking for everyone but, not all of us have the technical background (I don't) to understand the calculations (but, I still try to). Thanks!
@@RichRusso4218 maybe, but Honda also makes good CVT transmissions too and lots of other transmission's are not as long lasting as manual transmissions
Yes, and you haven't even touched on the odd ones. Start doing it for US machining and you have to start converting from Metric to SAE to things like Drill Index.
Growing up in public high-school in the US I learned to do science with the metric system. Went to college and on the first day of my introductory engineering course I asked why we weren't using metric. Professor looked at me like I was crazy. I think most scientific disciplines in the US use SI units but many if not most engineering disciplines still use English units.
because metric would be too easy, if you were given the answer right away you wouldn't learn that cars function in multiples of 8, just like computers 8,16,32,64,128,256,512,1024etc. my multiples of 8 are always right there.
Can you do a video, if possible, about "What not to do with a CVT transmission." Similar to the video "What not to do with a dual-clutch transmission? Thanks.
what not do with a cvt: send out to a generic garage for maintenance.. cvt's can be bulletproof as long as they get the correct and special oil and NEVER EVER NEVER!! get even a drop of generic ATF fluid or any other lubricant/oil in them. also the shifting (which isn't real shifting, just forcing the plates to move or stay) gives for extra wear on the belt and plates. if you could hack the cvt ecu and delete the whole shifting thing your cvt could outlast your engine. also CVT's don't take hauling heavy trailers very well..
Had a Nissan, hated the CVT but I did love it only when I put the acceleration on heaps. It really did get up and go. I mean it was right in the right torque zone. Watch the fuel gauge. Rest of the time it bogged down and was wanting to drive boring. Maybe there was something wrong with sensors etc. Sold it. Now got one of those dual clutch six speed in a Kia now. Sport mode seems to keep the torque there on hills etc. It's good and changes gears almost instantly. I could never do that with my left foot and right foot co-ordination. Don't thing any human could. My preference though is still the torque converter and planetary transmission with a locking torque converter. I know, these days it's all to do with fuel consumption and we don't have options.
Mark Kelly they cost you the same to buy but cost the builder a fraction of that to manufacturer and you're going to spend ten times more in labor cost because the cvt are in the shop quite often and they only get about one-quarter of the lifespan of a regular transmission
but CVT run hotter than any transmission + it makes the engine run hotter too, way weaker than any transmission and so expensive to fix if something went wrong. most of these reasons effects the engine lifespan which the major component of any car!!! that way me and every human's hate CVT
true but no one has even considered developing on for race or consumer fast road applications, and those problems you mention can be engineered out. remember, the IC engine was never perfect to begin with and to this day, is continuously being improved and fine tuned.
from the look of the thumbnail a CVT seems pretty simple. I wouldn't be surprised if there would eventually be a aftermarket company that would replace CVT internals for cheap. it seems even more simple than manual transmissions. also the reason why it's expensive is because it's new.
Exactly. People said the gas engine was too dangerous to mass produce because EXPLOSIONS!! Air bags were too dangerous to produce because EXPLOSIONS!! Electric cars aren't a step forward because them and their batteries are being manufactured using COAL!! Now Tesla is working on completely solar powered plants in the future. Where there's a will there's a way!
Andres Flores A Nissan March kept beating my stock E46 from traffic light to traffic light (basically an accel from 0 contest)... Although I only revved up to like 4,000 before shifting.
ThePatUltra well as a car enthusiast, I would say the Toyota Prius is really cool car, not just for the looks,how it handles. Obviously slow but who cares, it's more cooler to modify a Prius. And trust me, there's a lot fans out there that loves to modify a Toyota Prius. Mostly in Japan then here in the US. I would love to do that.😎👊🏼
Obviously there are plenty of people who don't see "coolness" the way we do. The eCVT is central to the efficiency (which is what makes it cool to practical people) of the Toyota hybrid system. The engine in the Prius is an Atkinson-Miller design: it has an approx 8:1 compression ratio with a 13:1 expansion ratio and that is done with intake valve timing (miller). Miller engines are wonderfully efficient in a very narrow rpm range, and the eCVT does just that - it keeps the engine in the most efficient range as much as possible. As far as "coolness" goes, I owned a Lotus Europa S2 (the older one with the Renault engine) for six years in the mid 70's. It was amazing to drive but a nightmare to own. To me coolness is defined by meeting my actual needs, not my desire to be thought of as flashy and hip. Even my first generation Prius gets me where I am going every time, taking snow in stride, and that is cool.
I liked constant RPM CVT transmissions. They were really good when calibrated right, just misunderstood. I particularly like how i can cruise all day just above idle, or floor it in sport mode and sit at 4-5K RPM and go really fast for my engine size. So they don't make proper CVT anymore? That sucks.
From the seat of a frustrated physicist, I enjoyed this informative CVT tutorial very much. "Some people" dis CVTs, but it is clear (to me) from this tutorial the current trend toward auto transmissions having more and more gears while coupled with dual clutches...gets closer and closer to a CVT transmission in practice....or didn't you say that in the video! LOL!
I believe the CVT is a dutch invention by DAF, they made cars that could drive as fast in reverse as forward. They actually did reverse driving races with them in the seventies and eighties, you could find videos if you google for them.
Nash had a car i think the metropolitan that had 2 shifters, one for forward and reverse and the other to shift gears go as fast backward as you could forward.
I drive on daily basis a car with a CVT transmission, is 17 years old now, and it's mine from 4 years. I simply LOVE IT! If you wanna the comfort and economy for a combustion engine, CVT is awesome. Only one thing, CVT needs to be correct exploit and serviced at the right intervals of time (or distance) with right oil and filters and they last in time. As a fact I was manager of a rental car company with a fleet of over 3000 cars, manual and automatic transmissions, all cars new from factory... I never find a more comfortable or economic transmission in that fleet of +30 models from various makers.
You should really think about doing TH-cam full time, sure you'd make more money than at a job, your ideas are awesome, and there's endless stuff for you to make videos, thanks for your work putting these videos up, sure it's a lot of work. You can even hire people to get more videos out which benefits us, and doesn't hurt your wallet.
+unbearable pain - CVTs have been developed for F1 (and subsequently outlawed), so yes they can be built to handle the torque and stresses of high performance applications. As he said, the biggest holdup is customer acceptance. No one wants to hear a Ferrari blasting down a straight away while the engine wails are a constant 9000 rpm.
I'm an Automotive Mechanical engineer for 28 years, been in the business for that long and I tell you:
Your knowledge and teaching skills are absolutely amazing, congrats man!
I agree ... but don't you think he should emphasize that it's the gear ratio (as he briefly touched on) that determines power and not "Horse Power" ..? WHAT does 5252 have to do with it? Right..?
@@trumanhw5252 is an engineering constant
It is really sad that manufacturers have been forced to "emulate" gear shift on cars with CVT because of a small number of whining customers. They should at least offer an option to enable a "pure" CVT mode where the useless gear shift emulation is turned off and the engine runs at the optimum RPM for any given situation.
I have a 16 accord with cvt I do not hear any shift or difference in engine sound at all runs like a fast golf cart just keeps going faster no increase in sound
Yes, it is sad. Why not exploit this CVT technology. However, I am still trying to get used to these fake shift points.
A lot of newer CVT equipped vehicles use different drive modes through a button that changes how the stepped portion works, but they usually still resort to stepping at some throttle level unfortunately.
I have both modes on my car. D and S
I won't buy a car with a CVT. I want gears, and I'll tell my car when to shift, just like my motorcycle.
This is funny. Everyone here loves CVTs.
Go to a car review, and everyone hates CVTs.
So you have never ridden/driven a quadbike,/UTV.SXS sports machine? They seem to do just fine. CVTs used to be called torque converters so coming into electric engines where 100% of torque is available at 1 RPM why shouldnt we use CVT efficiency over gearing which has been shown in sports SXS's not to be able to match CVTs yet??.
"Consumers dont understand it, they don't like it..." minute 1.00
@David M
Well, I owned a car with CVT and used over a year, at the end I hated the slow response of CVT. So, I sold the car and bought another with a 6 gear automatic transmission. What a difference!
I know omg.... I'm tired
People hate what they don't know or understand
@@Trex531 Your car did not have 100% torque at 1RPM like an electric motor.
This is the 1st video that I've seen that had praise for the CVT.
It praises the mechanical superiority of the CVT, but it also notes that most consumers don’t like them (I certainly don’t, they whir)
Ive actually always loved the CVT in my Honda Accords. I always felt it allowed me to stay at peak power "forever" when Im stepping on it which is nice, and it runs much smoother. The only complaint I have is stop and go traffic it sucks. When riding the bottom of the CVT during stop and go you can feel the CVT bottom out all the time. But other than that I love everything about it.
Loved the CVT in our ‘05 Murano and now in my ‘17 Accord hybrid!!! Just get in and press the skinny pedal. Nice and smooth.
The main problem with CVTs is that while they are theoretically the ideal transmission for performance/efficiency, in practice they are let down by sub par implementation. For example the slow response to changes in throttle input or the low input torque limit, and the high internal friction or less than ideal optimization of the actual gear ratio vs speed/engine load actually means they don't use less fuel than conventional transmissions.
There is also a psychological component to it, people actually like hearing engines rev up as they accelerate. If CVTs had always been the norm since cars were first produced people would be fine with it, but because they weren't people are used to the sound of an engine revving up and down, and the engine mantaining a constant speed while the car accelerates just sounds wrong to most people's ears. Sometimes a car with a CVT is faster than one with a conventional transmission, but *feels* slower. And humans are hardly entirely rational and objective in their choices, feelings play a huge part.
Besides conventional automatic transmissions already have a continously variable component to them (the torque converter) and with turbos and variable valve technologies engines have never had such broad power and efficiency bands, so there is far less to be gained from a CVT today than we would with for instance a 1970s engine.
Awesome concept, poor execution. Specially the Nissan ones. Rubbish.
I have a 2018 civic EX-T with the CVT in it and when you put it in the sport mode it immediately increases the RPMs to hover between 3-4K as opposed to the standard drive mode which obviously tries to keep you as low as possible. This makes the car feel very very quick and insanely fun to drive as you are always getting the full potential of the engine without any shift points. I understand the reliability issues these have had but if you are leasing or are willing to put that aside, the CVT is leaps and bounds more entertaining to drive than a standard automatic and performs way better. I trust that Honda has a more reliable CVT than what Nissan had so I’m sure the reliability issues aren’t as big as people think
I drive a 10 speed manual transmission truck and i love it, i get to shift gears constantly like they do in Fast and Furious
Haha
akupehsluarketatAR like john Connor in T2 ?
the more gears you have, you are approaching having a CVT, except with added complexity.
Mitch L., manual CVT with RPM knob?
It sounds like you're continuously varying transmission.
GM made a 2-speed automatic called “power glide”. Yes! Two speeds. A low gear for getting the mass stared into a roll then a variable speed (pressure) that continued across the power curve until max rpm was reached. Essentially a CVT but with a launch gear. Ironically, many top fuel dragsters and funny cars used the power glide because of those properties so much like the properties (young) Jason was outlining in the video! Great job, Jason!
Good point, but of course it is not quite the same, as the transmission did not change the gear ratio. (I'm not considering the launch gear in this discussion.) A cvt will change the ratio *as well as* keep the engine at peak power - a powerful combination. The powerglide relies on slip to put the engine at (semi-close) to peak power, but the power is being delivered to a single ratio, so the mechanical advantage is not there as is with the cvt.
The torque converter does apply a mechanical advantage. The torque input is greater than the torque output of the converter while it's slipping - typically up to double the torque at stall. It's not very efficient, but it's much more efficient than just slipping.
@@badavisuf I'm trying to differentiate between 'slip' and 'converter'. I think this is a distinction without a difference. A torque converter IS a slip device. It doesn't make extra torque. It only allows the engine to run at an RPM at a point where the torque of said engine is at its greatest or near it.
Still missing in the PowerGlide is the mechanical advantage of different gear ratios as suggested above.
@@sonicdewd It doesn't *just* slip to max engine torque. Torque output is higher than the input. The fluid is routed in a cool way through a stator so that it gets multiplied. I think Jason has another video on it. Also Wikipedia.
Super late reponse but a lot of Toyota's CVT vehicles also have a first gear for getting off the line before "shifting" to the variable gearing. Any vehicles with the "direct-shift" K120 CVTs have this quirk.
I rather like the CVT in my Swift, and I think it actually does do the smooth curve thing rather than mimicking gearshifts. Definitely feels smooth to me.
From the driver's perspective, the RPM is determined by throttle input and the ratio just adjusts to match that to the speed you're going. Hence the engine note does vary quite a lot - it likes to sit around 1000-2000, but if I put my foot down then it'll jump up to about 5500 RPM.
It's honestly just nice to drive.
I heard CVTs were bad, I drove one in a rental car on my vacation and it was very dull experience, BUT it was a very smooth ride and little to no noise. I would say if I was an old man winters and wanted to just chill CVTs are sick
Pretty much my experience. CVTs are good transmissions in theory. My problem is I just don't trust them yet. Planetary autos, automated manuals, and manual transmissions are known entities at this point, CVTs are relatively new to the consumer market.
As far as I'm aware, CVT technology has been available far longer than DCT or AMT.
CVT are the boring side of transmissions. They're dull but effective and reliable.
They've not been available as long as a standard auto or manual. DCTs have a ton of racing pedigree. CVTs are known to have problems in high torque applications, and at this point are pretty much only used in consumer economy cars.
I'm sure they will be more or less fine, but I'll still wait and let other consumers purchase the first few generations.
The STI doesn't have a CVT, and the WRX isn't exactly a powerhouse of a car.
That said, (according to COBB) the WRX with a CVT is down 30 HP compared to the 6MT and has different head castings. Has Subaru put lower power into the CVT car so it can hold together? Maybe, and the 0-60 times bear that out.
The most impressive thing about this is that you can do it all in one take (and without stuttering!!) I took grade 11/12 physics so this brought back some memories and I was able to follow but I could never explain it so flawlessly.
Appreciate the kind words! :)
+milattx He explained all of that in the video...
+milattx I think people prefer shifts because as you go through gears you feel an accel/deceleration pattern that people emotionally connect to speed, but the truth is that feeling as at a cost on performance.
Ha yes, I think he didn't breath either! He IS a ROBOT, confirmed!
Mekhanic1 Lol He really is good at master shots.
There's a good number of people asking about how the Koenigsegg Regera's transmission works. Just wanted to let those folks know I've made a video on it! Have a great day everyone! :) th-cam.com/video/naRY3knqFYU/w-d-xo.html
Interesting as always. In a future vid could you please do a in-depth on how unsprung weight effects the cars proformance and torque as well as the benefits and disadvantages.
Hell yes! I find this to be one of those subjects that seem to fall into the "black magic" category for most people. :-)
+dicksplatts007 love this idea! Yes lightweight wheel comparison or carbon ceramic brakes
Would putting a CVT in consumer cars also reduce price? With a CVT would it also remove the "jerkiness" of shifting? If it does, I don't understand why people wouldn't want one, they're just living in the past.
Nice overview, especially the explanation of torque vs power. I think understanding gearing is the key to understanding the difference between power and torque. Btw how do CVTs shape up in terms of power loss(friction) compared to manuals?
Also a cool topic to cover would be how lubrication in an engine works. I know the oil pump pumps oil from the bottom of the pan up to the cylinder head and some engines have jets to cool the pistons, but I'd like to know through what path the oil travels exactly and how it affects oil pressure and engine wear.
I “invented” the cvt in my history notebook while doodling instead of studying a few decades ago. I was convinced it would be best to enable a driver to manually control the rpms. my vision was for the ‘infinite ratio drive” to be manually controlled with a “shifter” that was similar to a boat throttle. The driver would move the arm forward or back to control rpm, or while accelerating, gradually move the arm to keep the rpms constant as speed increased. It involved fluted cones. Anyway, I’ve seen many over the years but unfortunately durability and efficiency have been issues. I’m still convinced it will ultimately be dominant. I hope I see that before I die.
This guy shifts!
some of your videos make my head hurt.
thanks!!
Lol, yes
+james pond lol, reply to yourself
true.
faisal3398 that's because there is a reply that doesn't show up on TH-cam.
step1-take asprin. Step 2-watch Engineering Explained. Step 3 apply ice pack to head. step 4-be smater.
I have a Nissan Murano with a CVT. Terrific! It always has the correct ratio vs torque and RPM. There is no problem if being in between the best gear ratio. I like the smoothness of the transmission no matter what speed or torque change is occurring.
The vehicle has some shift positions to simulate fixed gears. This allows operation at fixed ratios as if it was a gear transmission. This feature is great for situations where a trailer is being towed and the driver would prefer fixed torque. Also simulation of gears allows for compression when going down hill, or wanting to use the engine to slow the vehicle.
The only drawback I found is if the driver tromps down on the accelerator the CVT takes maybe a few milliseconds longer to get in to the proper ratio for best torque to accelerate. I am being very critical here. Since I am not racing my vehicle this is not an important concern for me.
My preference is to keep using vehicles with CVT over a standard automatic transmission. A manual transmission with a clutch would be the exception, but for city driving I would prefer a CVT.
I have a Nissan Murano and I HATE the CVT. It never seems to be in the right RPM. When that happens, I just push the shifter handle to the right and BAM! The car accelerates quickly like a rocket, but the RPM's are way too high. I'm more of a manual transmission fan anyway.
Smoothness?!? I knew someone with an Altima CVT and the engine sounded and felt like it was churning itself to death
Mine sort of sounds that way too. Sometimes it sounds like it's slipping. It's weird. I prefer driving my '74 Duster with a 4 speed and a Pistol grip.
Again the problem is it is a Nissan, my Jeep has a cvt and after you get used to the fact it doesn't have the gear shift feeling, which is nothing more than a mental thing, it is great. It is always in the optimal mode for acceleration, cruising and braking. Engine braking is progressive so you have less brake pedal effort on normal braking and that extends brake pad life.
I've had a rental Juke for over a week now coming from a 5-spd Altima. I actually think you've figured out the right way to drive with a CVT. Instead of just choosing one mode or the other, use D or +/- situationally all the time.
When I first got it, I was driving it more like an automanual choosing to see which mode I preferred. Now, I vary it depending on what the conditions are. It was strange seeing how slow it felt in D, but I'd look down an realize I was at a higher speed than I realized.
I think the high RPM sensation might have to do with the way Nissan has programmed the "gear" steps. Of course the highest ratio seems MUCH higher than usual in a geared transmission, so maybe that has something to do with it.
Does it have an I-4 or V-6?
Have you pushing the pedal down further while in D to get the Murano to step down faster instead of +/-?
Liked and subscribed as you come across massively intelligent without sounding like an arse! Hard to find on the internet! Keep it up!
Thank you for subscribing Mike!
I agree, just a guy genuinely trying to pass on his knowledge without acting like he knows more than others.
The thumbnail had me believing I'd see the transmission in action. I am utterly disappointed. :(
Exactly. Like one of those thumbnails with awesome cleavage and never shows the girl
You can see it in action on scooters, every scooter uses this transmission, and there are videos of scooter CVT in action
Every video he has is like this, he isn't very good at this youtube stuff.
@Meme Man all they are good for is a golf cart!
@Meme Man yes nothing that makes power, I can’t stand when I see companies continuing to use CVT’s when all they do is fail and fail badly and quickly.
I like the CVT in my Crosstrek. It works, the car doesn't lag behind when it needs to shift. It's great.
They do have manual shifting in it as well which is really nice for when you need power ASAP. Just tap the downshift paddle and it downshifts and then goes back to normal CVT operation seconds later.
I'd definitely take it over any auto transmission any day. A manual transmission to me is something for fun just to get that feeling of smashing in the clutch and changing gears. Other than that I know it's just a novelty.
I know for a fact my stock getrag f23 5 speed manual transmission could handle 3-4x the amount of power your cvt transmission would hold. Not just a novelty item but a must have in some situations.
The problem with that is that it doesn't need to shift. It does it to mimic standard autos
Not sure durability is that big of a problem since the majority of really big farm tractors a beginning to use CVT's.
Really..... that transmission at stock is going to handle over 1000hp? Really.... pass whatever your smoking this way
there is no shift in a cvt, you need to find out how cvts work and then you will be disgusted by the cvts that upshift like automatics. cvts are like a band that you pull and that band doesnt have only 5 different pulled positions so instead of changing gears cvts should have something like pulled percentage like your volume nob , with the + shift you go to the highest "gear" which is 100 and with - you reach 0 the lowest "gear", paddle shifters on cvts should act like volume nobs, shitty audio players offer you 10 different positions while the good quality ones offer 1000 different positions so the same goes for cvts the race car cvts will have 1000 different positions while your maxima is trying to be an automatic but should have 50 different positions.
What did he say at 0:08? Soulless?
Yeah
Without a soul
Wonderful presentation! It’s a shame that F1 has disallowed CVTs as the technological advances would be much more rapid with all of their funding.
*had
- This is a message has been approved by the Grammar Nazis
If F1 used CVTs then it'd probably be disastrous because imagine today's 1.6L Turbocharged F1 cars revving at 15k RPM for almost the entirety of the race. It's too risky
@@anonunknown933 in this case i agree that it would be has, because them disallowing CVTs is an ongoing action. if i got a car a couple years ago and i still have it, you wouldnt say "he had that car a couple years ago"
All they would have to do is make all drivers use the same transmission
@@FauzaanSharieff don't you think they'd have thought about it and designed the engines with a different power curve if cvts were actually allowed?
To everyone complaining about the reliability of CVTs, Im guessing you dont own a Ford Focus with the Powershift transmission. These DCTs are notoriously hard on clutches. We had so many of them coming through the shop that we had to buy the tools needed to replace the clutches in them instead of sending them out to the Ford dealer or a trans shop. They would shudder so badly it was hard to drive, many times just outside warranty limits. In fact the majority of trans failures were conventional automatics, though we did see some Nissan CVTs come through the shop needing replacement. My experience with CVTs, as a 30 year auto mechanic, is that they are just as reliable as any other transmission, and WITH PROPER MAINTINENCE can last just as long as any other trans. Throw in the fuel economy improvement and I wouldnt buy another car that didnt have either a CVT or manual transmission. Most problems I see are from owners who did not properly maintain their vehicles, then saw the high cost of getting it back on the road and decided to blame the manufacturer.
This!! Maintenance negligence is still a thing which obviously a problem for US American operating economy car!
@@edgaryzen4925 I was shocked at the condition of some of the cars coming into our shop. Brakes don't just suddenly eat into the cooling vanes of a brake rotor, valve cover gaskets don't suddenly leak 5 qts of oil out of them, and expecting an automatic transmission to last 150,000 miles with 0 attention is just not smart. Many people were driving around with obvious problem after problem until the vehicle simply would not move further, then wanted to complain when they get a $5,000 estimate. If you had addressed these issues 40,000 miles ago its likely the estimate would have been 75% cheaper.
I had a 1978 Ford pinto, it was brown. Hope that helped.
And you're still alive? Kudos.
Everyone thinks that auto igniting vehicles is a new invention by Tesla,
but it was already perfected by Ford way back in 1978.
LMAO!
I really hope you don't get rearended
CVTs are all well and good, but they are woefully inefficient (I'm one of those race car driver guys he talks about). Yes, in a perfect world of mathematics, CVTs do produce a better application of force. Where they fall down though, is when you add physics into the equation. CVTs are made to hold the engine at a steady RPM at variable speeds. It's sounds like magic, but on consumer grade cars, they're nice for fuel economy. Now, where they fall off is during aggressive driving... and track cars are all aggressive, all the time. Take a Corolla out and put it on the interstate at 75mph. Now, put it into passing gear. There is a a long, noticable lag in the downshift procedure. Now, slam on the brakes and accelerate hard in quick succession. You can do that a few times until the transmission gets locked in a "low" ratio and robs you of all power until it normalized. In a race car, this is unacceptable since cornering requires hard braking and quick, hard acceleration 30-50 times per lap on some courses. The CVTs also produce a tremendous amount of heat in comparison to standard transmissions work. This creates an entirely different set of problems for performance engines which can operate 50 or more degrees hotter than a consumer grade engine. Lastly, you also can't really tow with them because adding additional weight to the vehicle will cause the CVT to keep the vehicle in "low" gear and ultimately overheat itself or the engine... or both.
As far as the corolla goes, that's only a matter of the computer telling the CVT what ratio to use. The CVT being in a low ratio after deceleration isn't something intrinsic to the CVT, just a lack of sporty programming. Try a Nissan with 'sport mode' or a WRX CVT and you'll find that after deceleration, an aggressive ratio is waiting for you to smash the pedal. Remember, CVTs are 100% computer controlled using inputs like load sensors, speed sensors, gas pedal position sensors (they're drive-by-wire) and translating the available power and power demand into an effective RPM and ratio combination.
I don't know enough about the thermal properties, but since it relies on friction, I could see it making more heat. As for towing, well that's just a bad idea. If the engine can produce enough torque and the CVT can handle the load, it'll be fine. Nothing about the CVT itself is going to lock it to a 'low gear', but given how they work, towing would just put too much stress on it unless it was designed to handle the load.
There is friction and heat. However, it's more or less about the infancy of the tech in relation to materials and its ability to disperse heat. Look how far normal clutches have come over time. Same goes for oils. CVTs in their current state are still relatively new and have a lot of challenges. Eventually, someone will take up the banner and solve the problems. Well.... they kind of have in Nissan making everything have one. With that said, they chose a different trans for the GTR and electric power in hybrids is supplanting that need to have something "shiftless". For a commuter or weekend warrior... it's perfect. For the other 5%, well, it'll get there eventually.
You are correct, CVTs aren't good at performance driving. I've watched F440/500 formula cars autocross with their 2-cycle snowmobile engines and CVTs. They must keep their RPMs up thru the corners not lifting off the gas.
Yes, agree totally. In the UK I have driven and owned manual-boxed cars, robotic boxed cars (i.e. Manual gearbox with electronically controlled change), automatic and CVT. Without question, the CVT box is the one I would actively avoid as to use they are rubbish. Hateful things! And trying to hill-start with a CVT is often a nightmare of screaming engine and fighting rolling backwards. And they are noisy - they maintain this booming whine as they try to maintain their constant velocity. I'm sure they would be fine in a milk float but in a car they are hateful things.
Happens all the time in my civic
I had a CVT about 15 years ago and loved it. It accelerated so smoothly. It was deceptive because the engine doesn't rev and shift. Before you knew it you were flying!
Where it was really nice was towing a trailer through the mountains. You didn't get that hard shift like with other automatics. It was smooth and confident.
We did not have reliability problems. But I'd like some hard data rather than individual anecdotes.
I'd get one again.
2007 Nissan Murano 188,000 miles hauls ass
The first CVT I drove was my mom’s 06 or so Altima. I floored it, and was immediately impressed with how it accelerated. Today, my wife drives a 2019 Outlander Sport with a CVT, that performs well. If someone were to actually develop this transmission to take power, it would really be a game changer.
Nissan has they put in the maxima with 300 horsepower and he’s made a video of their high torque cvt they just don’t use it
next video request:
things not to do with a cvt
keep up with the good content man. I've learnt so much from your videos 👍
yes please !
*Learned.... the irony
1. Drive them
+Kwabena Asamoah actually, if dude is from the UK, learnt I'd an acceptable way of expressing gaining knowledge in the past tense (and, therefore, actually in American English as well, though we tend to use the suffix -ed over -t in the past tense). The more you know!
*is
This guy is so damn smart! I'm glad that he has a passion for high performance automobiles instead of dinosaurs or planets, erc.
Well dinosaurs and planets are cool too, try web development or something.
Welp, he says w instead of omega, i find a lot of inconsistencies in his videos
Well, he did mention dinosaurs, you hear him say how great manual transmissions are? :-P
He is an Engineer - don't you dare criticise him. :)
@@dinosoarmotorsports that is pretty funny! (Manual owner here) I do have autos too, though.
I don't mind cars being like a constant RPM propeller plane.
@HiWetcam Diamonds do exactly that. You don't have a prop lever anymore, it's all FADEC'd. You simply push forward for more power, the FADEC figures out the optimum engine rpm and sets that. So at cruise my DA40 typically uses around 2050 rpm, but if I firewall it, it goes to 2400 rpm. Funnily enough, it also gives you the ability to use the prop as a speedbrake. When I pull the engine to hard idle, the rpm suddenly goes from 1800 rpm to 2200 rpm, but not by increasing fuel burn. The FADEC recognizes that you want to decelerate, so it shuts off fuel injection and turns the prop to flat pitch to use the oncoming air to turn it at high rpm, maximizing propeller drag. With this effect in play, you can absolutely dive-bomb it on approach.
@@totoritko So an engine brake, neat. A
@@totoritko if cars had anything like plains most drives could not even get it started!! let alone figure how to put it in go mode
Had a 2011 Mitsubishi LancerGT with cvt and paddle “shifters” to help simulate actual shifting. Had absolutely ZERO issues with the car. The wife loved the fully auto mode, while I loved the ability to use the paddle shifters to select my own “gear” to accelerate in.
I would have no problem buying another one, as long as it had the ability to select between fully auto or manual selection like that one did. Loved it!
I've owned manuals, CVTs, and autos. CVTs set up in a performance in a vehicle (ie snowmobiles or atv/utvs) are insanely fast. I remember my friend who owned sports bikes for years bought his first sled (670 2 stroke cvt) having the expectation it wouldn't be able to compete with his GSX-R nearly pissed his pants when he punched the throttle for the first time. He had the biggest grin I've ever seen after his first drive. Call CVTs soulless, but I like having that power "right there" all the time.
My mom calls it "go"
She likes her vehicles to have "go"
+Joey Zuraski I would advise you to check your fuel line for leaks...
Well, I got 43 MPG in the Civic vs 37 MPG in the Elantra in the same daioly commuting and with very similar engines between the 2 cars. The Civic is CVT, the Elantra is traditional Auto.
It's not that they're soulless, it's that the drone makes me literally want to kill myself. It's the same reason I hate electric cars (road drone from no exhaust note and also the fact that it's electric) even though in reality Teslas are badass, if expensive.
I didn't understand how my Outlander worked, but it's crazy being in that torque band and accelerating 100% of the time. It's like a rocket.
Completely have a new found respect for CVT's. Great video.
Yep. This video is correct. He completely left out the fact that if you adjust your CVT to maintain the engine rpm at the torque peak instead of the horsepower peak, the engine will get the best power out for fuel in. You also have to account for reducing the RPM to as minimal as your engine can be smooth at steady state speeds. For instance. My Dodge Pickup with the Diesel engine has the torque peak at 1600 RPM But if I drive at 55 mph which is 1600 rpm in 6th gear (manual trans) I get about 22 mpg. If I drive in 5th gear, 2400 rpm, my fuel mileage drops precipitously. If I drive at 35 mph in 6th, the engine is turning about 1,000 rpm and still gets better fuel mpg than if I'm in 5th gear. Only slowing below that speed actually requires me to downshift so that the engine is not lugging. So the video is correct for acceleration but not for fuel mileage. The CVT will only maximize fuel mileage if it's set up to cruise at the lowest rpm the engine can handle. The reason that corvette has 6 gears instead of 4 as used to be the most, is to keep it nearer the point of maximum power in the power band. The CVT may actually be more efficient than a manual as well for maximum fuel mileage but whoever is writing the software to control it had better take all that into account. My Suzuki Burgman had a CVT and it wasn't optimized. It always used higher rpm than the engine needed, especially when at a relatively low speed, 30 mph vs 50 or anything like that. I'll stick to my manual transmission, so I can control the gear selection rather than an improperly programed computer or spring and clutch set.
I'm really thankful that Mitsubishi in the Lancer decided to only go with the stepped gears mode in the higher end GT models, and only when in "manual" mode with the appropriate shifter with +/- on it.
the ES, the literal bottom line model, just has a "drive" and a "low" gear. this is hands down the best CVT configuration you can get in these cars if you go with a CVT, and you should avoid the type with the +/- on it for reasons outlined in this video. if you have one with a +/- shifter, swapping to the "low" style shifter is literally just plug and play, as the TCU is programmed with both modes and uses the shifter to determine if it needs to have a simulated gear mode or not. the "low" style shifter is also usually easy to find and fairly cheap, as most people consider it the inferior shifter (which is not the case!)
"drive" focuses on peak fuel economy, and tries to keep the RPMs as low as possible for a given throttle position to keep your fuel economy high. "low" on the other hand does the opposite and tries to keep your car at its highest RPM for a given throttle position so that way you can accelerate and decelerate as quickly as possible.
the result is the best of both worlds of fuel economy and peak engine power selectable at will. when driven properly you *do* end up shifting a a fair amount between "drive" and "low" because they're basically a selector between "do I want high or low RPM?". being effective with a Lancer CVT means mastering which gear to be in and when exactly to shift between them and when to stay in one or the other. it's a thing of beauty!
the CVT comes with some downsides (like frequent and expensive service intervals, especially with hard driving) but IMO the CVT Lancer ES is something everyone should experience at least once. it's an experience you can't get elsewhere and is the CVT experience in a car in its peak form!
- β
Make sense. Thank you. LOW HP reliable engine such(as the 3A92 as it been around for 20 years) and Mitsubishi Mirage do couple very well! The Mirage’s CVT for model year 2014-15 used to be just D and B. Since 2017+ model year, it is D, Ds and L.
YOU HAD ME AT "HELLO EVERYONE & WELCOME"
hahahah yup .. the rest tho ?
And lost him right after that : )
I actually followed the majority of the math & reasoning,...after swallowing a Prozac, Demerol, Xanax cocktail.
8000RPM
I did an 8 ball with 3 shots of whiskey and followed it perfectly
@@countdown2xstacy it's an 8th ball try hard
Oh god really? I would have been too busy walking to the 711,(not the closest one), down the middle of the road swearing at traffic to get some peanut m and m’s barefoot without a shirt on and then waking up remembering nothing wondering why my bed was full of m and m’s and wondering why my girlfriend had the shits with me lol.
Water & extra sleep make his videos more coherent to understand. Love the clearly explained physics :)
Anybody got anything for me ? Just bought a 2014 Nissan Maxima just turned 30,000 Miles. So far i Love it, took a little while to get used to the CVT, think it's a Great idea for a everyday driving car, for good fuel mileage, Not a Good design for any type of Performance Driving. Maybe i need to start taking a little more Narcotics, Like You Guys said.
Fun fact: CVT transmissions were banned from F1 in the 90s because they were too fast.
lol really? do u have the link for that?
I'm pretty sure it was actually because the noise of 20+ cars whizzing round going 'wherrrrr!!!!!' at the same pitch constantly would be insufferable.
Yeah, because F1 cars are so pleasant to hear as they are.
+MIZKable www.f1fanatic.co.uk/2007/05/03/banned-continuously-variable-transmission-cvt/
***** hahahaha u served him
Said this in the short, repeating it here: hybrids that have an eCVT actually have a system that's better than a belt-and-pulley CVT simply by virtue of not being limited by potential belt slip. eCVTs are typically a planetary geared system, where you have the engine on the sun gear, an electric motor on the planet gears, and then the output of the two combined into a ring gear. Varying the speed of the electric motor so it either partially counters the input of the engine or adds onto the input of the engine results in varying the effective gear ratio, and it doesn't take that much electricity because, as it's doing this, at the other end of the common power split gear is a much beefier electric motor that not only can propel the vehicle on its own (so the engine gets shut off at low speeds for the hybrid's EV mode) but it also acts as a generator to facilitate both regenerative braking and supplying the electrical power needed when the smaller electric motor is working against the engine to produce a higher gear ratio.
CVT's are mainly used in cars to conserve fuel (save money), yet these CVT's don't tend to last nearly as long as a regular transmission. The money saved on fuel, won't replace a 5,000 dollar CVT. Apparently they cost the auto makers less, but is not reflected in the price of the car.
You could be correct, Idk to what degree without scientific tests. A big chunk of that is labor taking it out and putting it back. Would be great if you could replace a clutch or CVT belts almost as easily as replacing a serpentine accessory belt. That would mean a little extra space and a little weight I think, but you would really think it was worth it when it needs service. Had to rebuild auto trans in 98 Accord 4 cyl at just 50K miles. You have to baby those clutches too. No trailers over 1000 lbs, no aggressive driving. I feel the same way about timing belts they could definitely make those easier to get to simply by making a point of it. There is no real gain by packing the engine tranny/ area to within an inch or 2 of it's capacity. You can design access in with no penalties if you design it through more. But a rebuild on a CVT should be no more than about 2-3k at the most. Take it to dealership yeah they will gouge. So you are right, one failure can cancel years of gains.
But my point is all the other tranny types including manual clutches can need service prematurely too. Kinda depends on the model, it's vulnerabilities, and you driving style/uses I guess. If you babied some CVTs they might go really long too. I would try one for my next car if they were still doing them and if hybrids weren't coming that use same idea. Alternator/battery/motor acts as CVT there, engine can run constant higher RPM at peak efficiency to supply electricity.
also CVTs are limited to the friction that their belts have.
its a lot easier pushing hundreds of ft/lbs of torque through steel gears than a rubber belt.
+Sam Hall Most vehicle CVTs use a steel belt.
+laboye So a chain?
+Sam Hall No, a chain means grooves and cogs. It's a steel belt.
I have driven my CVT powered car for 8 years and can say that a CVT acts like a turbo charger except that the boost is at low speeds rather than high speeds. If I step hard on the accelerator, the motor revs as high as I want within a second or 2 (maximum power) and the variable transmission changes gradually changes as I accelerate from 0 to over 60 mph without changing the revs at all. There are also no jerky shifts along the way. Unlike a turbo charger, this transmission can also optimize the RPM’s to save fuel and still give sufficient power when going up hills etc.
Bottom line is power and performance when you want it and gas savings all the rest of the time. My car has driven 168,000 miles or 280,000 km since I bought it new and the CVT is still going strong. This is technology that has to be seen to be believed. I still feel the magic from my 3.5 liter motor combined with a CVT, even after 8 years. Thanks Nissan.
David Clark yes I have a 2007 Nissan Murano and it hauls ass
Biggest issue I’ve seen is reliability with CVT during the early stages of manufacturing. Nissan struggled hard to provide a reliable transmission. The technology has increased so has the reliability.
Nate Bryant mine is a 2010 altima I bought 4-5 years ago. Surprised it’s last me this long cause I beat the crap out of it. Number one enemy for cvts is heat. Changing the fluid and filter every 50-70k miles is what has helped mine stay alive. It used to whine after 2 hours of driving in Texas heat but been quiet ever since i changed the fluid
Me awhile ago "I love vehicles! I wanna be an engineer or a mechanic!"
Me now after seeing math "I think I really like just looking at cars"
Little Teapot now that’s funny 😄
That's kinda sad. That was just algebra.
@@saisr1 It is very sad, I went from loving and excelling at math, and forcing teachers to teach 2 classes simultaneously in the same room because there weren't any other students who advanced with me to warrant making another class (country school problems), to hating math. I was getting sick every 3 weeks and missed so much the school forced me to leave rather than qualify finishing that year, I never rebounded from it, only gotten worse. Myalgic Encephalitis claimed all my mental executive function and memory and I have never been good at even basic math again. But what isn't sad is that it forced me to more deeply appreciate the beauty and aesthetic of everything.
@@LastAphelion well hopefully you have found something that you can enjoy.
My BS was in mathematics. I haven't barely touched it for the last 18 years so I don't recall much of it, but I can still follow along when people explain things in mathematical terms. I do remember algebra halfway decently so this was ok. But all the upper division stuff I did, very little is retained. I often wonder how far I could have gotten with it had I gone to grad school for math. But the BS seemed about at my limit when I finished up. Everyone else around me in the math department were all way better at it (with the exception of the math education students who were only going to teach HS level math anyway). Everyone but me from my graduating class was going on to a masters or PhD program. Some of those classes were down right awful. Topoly for example. 8 students including me. The other 7 were either headed to grad school or were already enrolled and then me. With my head spinning.
CVT has been in atv's for over 20 years and have proven to be pretty awesome and getting better every year. Side by sides are so fast because they can run at the perfect rpm all the time. They've proven to be durable and reliable too. In fact, so durable and reliable that Yamaha has a 10 year belt warranty
Though guy's are saying below that CVTs were being used in F1... I thought one of the limitations of CVT is that it is difficult to build one that can manage the stress of a high output motor and remain reliable.
Enough money can solve any problem. :)
If you mean enough money into R&D, perhaps. But as it stands, the money you speak of is per vehicle. And even at that, it's not doable.
+Engineering Explained having a spare and rebuilding your engine every race also helps.
Well the one for F1 beat the track record by 7 seconds which is crazy so cvt trans are now banned from F1
FadeKing I don't know about any lap turned except in the wet, but F1 does indeed ban any real tech. It makes me laugh to hear someone say that F1 is about high technology....
I have a 2010 Nissan Maxima Sport Package, it has a CVT, and it hauls ass to say the least, not a super car or exotic, but for your "average" car it a beauty🙏🏼 I drive the hell out of it and never have problems with any components. I love it
Hows it doing 1 year later?
Yeah is it still good?
Soon.
I had a 2010 maxima too, done 210,000 kms and sold it absolutely no major issues at all. Missed the car so much I got a 2012. Currently 163,000 kms super reliable
Cajatron yes I have a 2007 Nissan Murano with a 188,000 miles and it hauls ass off the line and I be speeding
When my Nissan cvt fails I'll bring this equation to the dealer's service manager and see if that gets me a free transmission...........
🤣🤣🤣 he's going to say okay okay here get the dam transmission yo 🤦🏾♂️🤣
I am actually a service advisor at a Nissan dealer and Nissan's CVTs are absolute crap and do not hold up well to any abuse and heat kills them.
Ha El: Well, at least you'll give the staff a good laugh!
What we all need in these dark days!....... Stay Safe.
@@tellyourmomisaidhi8598 or lets be a bit more fair Nissan is absolute crap.
Ill do the same with my wrx 😂
I love CVT in my 3.5 Nissan Maxima it’s very quick! Great on gas ⛽️ Great on highway cruising, Great around town, stop light to stop light
As a mechanic when the cvt first came out I was replacing around 3 a week lol. The belt driven one would have the belt come completely apart and the chain driven one would slip and scorch the chain and the main bearing would come apart too 🤷♂️
Hasn't changed much, I am still replacing them left and right. Junk systems
All for Nissans right?
@@fnvideos4233 yeah and some kias that have cvt now. But Kia warranty sucks. I got about 7 to 8 hours for a Nissan cvt, kia is a straight 3 hours warranty 🤦♂️
@@fnvideos4233 I have been replacing them for Toyota and Subaru as well, just not as often as a Nissan. They aren't good at all.
@@79Bunta Honda makes a good cvt from what I have heard
Once again, the consumer is shown to be the weak link in the free market.
I think if every consumer was as smart as Jason, it wouldn't be a problem haha
One cannot assign blame to a concept.
I did not say the free market was a problem. I said the consumer was the problem with the free market.
You should read what I said before going on a tirade. Just a life pro tip for you.
Consumers are also the strongest link in the free market.
It's hard to saw what type of car was struggling to have adoption of the original CVT designs (e.g. sports cars) as some people may prefer a certain feel with the type of car. I'm under the impression that the vast majority of vehicle owners prefer fuel economy over engine sound/feel. As this video shows CVT are more practical for fuel economy, many consumers on that side would then likely prefer CVT transmissions. The consumer base wanting more fuel efficient cars (as one of their top characteristics) would likely choose a CVT car if better fuel economy despite stepless gears, over stepped gears. Again, I think it may have been car enthusiasts that the original CVT didn't appeal to. Consumers have been demanding want more fuel efficient cars..and the development of CVT may very well have come from the market forces to create a product to meet that need to stay above competition.
curioustgeorge03 I agree with that completely and stand by my original statement.
That's like saying "once again, friction is the weak link in tyre wear".
I really liked watching this bro, very well explained!
Thank you!
+Engineering Explained 👍👍👍
This is why future electric cars will outperform anything we experience yet.
No gears, no complexity, no drops in traction just pure performance
(assuming an intelligent traction control software).
Really poor range especially on lighter weight vehicle like scooters and motorbikes I am assuming their torque always overcomes the inertia needed to start the bike/car moving so why no CVTs to adjust the amount of Revs actually delivered to the rear wheel to improve range befuddles me.
and if you have a motor for each wheel you dont even need differential's. just a sensor and a computer to adjust power output.
Electric vehicles produce more pollution to manufacture, and operate than gasoline vehicles. FACT. Also they are impractical until they can find a way to produce electricity onboard, and not have to rely on hundreds of pounds of environmentally polluting batteries.
Not fact. EVs produce more pollution to manufacture, but they don't produce any pollution driving. And if you charge from solar panels, that's NO POLLUTION at all.
Batteries don't pollute. They only need mining lithium and cobalt. When batteries start being recycled, then less lithium and cobalt will be mined.
If you can charge at home, EVs are MUCH MORE CONVENIENT AND PRACTICAL. Up to 600 km every day and dirt cheap.
Watch "Range anxiety is a gas car thing, not a Tesla thing" on Tech of tech channel.
@@ryotaryuu initially, yes. But they achieve way higher mileages. Tesla is close to getting their batteries to last a million miles. You'd need to build at least three ice cars to cover that.
And we are just starting. Electric cars went viable only recently, they will get mich more efficient in the future.
"I wouldnt want constant RPM"
"Why?"
"Because i want my engine to spit fire when i shift"
Unless your car is modded so that your engine spits fire (mainly exhaust mods) then you really shouldnt care if your car is at a constant rpm
I can kinda agree though cause wouldnt the constant drone get just a little bit annoying? Just my opinion though
@@tbros9995 depends on your buffer. your car has loads to buff the sound anyways. so even if you delete your cats and muff, your cabin has enough to buff out the sounds.
Plus you'd be playing music on top of that.
It does not matter if you care about the constant buzz since it would be the same impact as cruising in the highway at a constant speed.
As for stop and go, that will break your monotonous noise.
What!? I can’t hear you because of my glasspacks and pipes!
@@brucelombardo i wish i had glasspacks
Plus I believe if it's at a constant rpm it has to mean less engine wear. Every car I have owned has been manual, but even I start seeing the benefits of cvt as they advance and become reliable
Those who put dislikes definitely are not engineers and neither that good with math. I am a mechanical engineer and I find this very informative !!
@@waldolemmer TH-cam can be educational, too !!
Bravo and to the haters of CVT here's mud in your eye.
I'd rather be a pleb than a dick
@fuckoffgoogle
wrong, the torque limitation only applies to belt driven cvts that slip at high torque. there are other transmission techniques that have the same effect as a cvt, such as transmitting the power electrically in a serial hybrid setup, or whatever toyota does in the prius which does not use a belt driven cvt. People don't like CVTs because they think the engine droning at a constant rpm is boring, but whether you want the best power or the best fuel efficiency, cvts are the way to go.
Most performance cars don't use CVTs because "performance cars" are not 100% performance oriented, because your average fast car buyer thinks gears are more fun.
But you know what vehicle does use a cvt setup? Diesel trains. Diesel locomotives use an electric transmission in which you have a diesel generator sending power to electric motors that move the train, and that is essentially a CVT because the diesel engine is always running at optimal efficiency for the power demands, and diesel locomotives regularly deliver power in excess of 1000 hp.
That's not true. CVT's can be engineered to be quite robust, but no one uses them in performance cars because they know their customers. The real reason is because the average car buyer likes to see the RPM needle go up and down, and that's because the race cars that sports cars emulate have needles that go up and down.
At the same time, they're not used in racing because that means spending a ton of money on development, and they might only be marginally faster than existing transmissions. If it wouldn't result in a big enough gain to win, I doubt many racing teams would spend the time to develop.
That is, if it would even be legal. It might create a massive advantage in another way. If all the transmission has to do is keep up with engine output, the driver doesn't have to do much in the way of thinking about the best gear to be in.
Whats so hard to understand? A cvt allows you to always run the engine at peak power and/or efficiency for a given throttle setting by adjusting gear ratios between engine and wheels, thus allowing the engine to always run at optimal rpm. A serial hybrid setup allows you to always run the engine at peak power and/or efficiency for a given throttle setting by replacing the mechanical link between engine and wheels with an electrical link, thus freeing the engine to always run at optimal rpm. In fact, the 2014+ Honda Accord hybrids which basically uses a serial hybrid setup for speeds 0-40, calls its transmission an "e-cvt" as in electric cvt as in its called a cvt because it has the same goddam effect as a cvt.
And you know what, the Tesla Model S is powered by 70lb watermelon sized motors producing 360hp each. Stick four of those motors in a car and hook it up to your favorite V12, and the result is a supercar with all the instant torque of electric cars, all the power and range of a gas car, and no complex gear-stepping transmission to speak of.
Your're rant is right. I've driven early CVT vehicles and it was music to my ears because I understand their simplicity and efficiency.
Question:
Is CVT more fuel consuming in aggressive driving (High speed, kickdowns) compared to normal 6-speed gearboxes?
Please elaborate on why asking a simple question is bring a troll.
Thats definitely a good question because when I drive very spirited (to say the least) in my altima, gas mileage is horrible
Well since if you floor it the gearbox will hold it somewhere near the rev limiter continuously, producing max power, it will also increase fuel consuption
НАТО в шоке, США обосрались Asking the real questions!
Joel Ranglin That what I've been noticing in my friends Qashai too.
Which units are used in that book - SI or 'murican?
Good question! My guess as it's written by "Randy Beikmann, PhD" is that it is American (published by an Americna publisher), and uses American units. (Amazon doesn't seem to have "look inside this book" for it ... also it's nearly $60). - Although I just found a review that states "You will have to live with two sets of units and a few other physics/automobile language idiosyncrasies, but that does not present much of a problem."
academically STEM majors (assuming the author is a physicist) metric is standard not imperial, even in America. I doubt you would have any trouble either way though because conversion is easy and is likely addressed in the book.
I am an engineering student in the U.S. all physics, chemistry, etc. is in metric... but again, conversion is easy either way anyway.
definitely not universal, though. I haven't used the metric system since college, actually (I'm in the US).
i'm not an American and imperial units confuse the hell out of me!
+Scot Mcphee same here. I'd gladly buy that book if it was written using SI
Makes me kind of proud to own a 2018 WRX with the CVT automatic! Thanks for explaining this
Its slower tho Lol
I just looked at buying a taurus x about 8 months ago. I called a friend at the ford dealer in the shop for his thoughts on it. He said well it came with 2 different transmissions a cvt or a 6 speed. He said you do not want the cvt because no one works on them and ford doesnt have parts for them let alone a new in the box replacement. You will be limited to junk yard only if it goes out. It had the 6 speed but i didnt buy it after we ran the VIN number. Also a friend up in Detroit had a jeep with one in it that started going out on him. They rebuilt it and about 6 or 7 months later that one went out. It was his wifes vehicle and she is not an aggressive driver.
I love my CVT bike, but wish it could sit at lower RPM when I'm moving slowly and don't need that power, so it would be quieter. With my geared bike I have control over that.
Christie Nel cars have cvt’s with hydrolic solenoids instead of rollers in bikes... i hate finding the right roller weight springs haha
Christie Nel You might try heavier roller/slider weights in your variator, which can also sometimes produce a slightly higher top speed.
Good basic explanation on the physics of CVT. The road load and driving force management side regarding adjustability and linearity is also a big plus for CVT. High power applications are limited by cvt belt and pulleys production costs and overall efficiency from friction and oil pump losses.
When he said this is all simple math equations 😭
made my 10 years old math classes flash before my eyes where i was busy with women instead of math. *wipes tear*
It's like 8th grade math. Nothing to it.
@@Vikesh7896 womans of sites with X in their names?
@@haha71687 8th grade math, combined with 11th grade physics, but yeah, this is pretty tame stuff for anybody who's taken even a casual interest in the physics of engines.
As a final year Mech Eng student - they really are simple. But even while learning this stuff we struggle to make all the connections. Most problems are fairly simple to solve once you have ALL the tools and equations to hand, and don't make any mistakes or detours on the way...
I feel smarter every time I watch your videos. I own a 2020 Kia Soul x-line with their IVT (Intelligent Variable Transmission) and it’s fantastic. Going up hill it doesn’t search for gears because there aren’t any! If I’m caught in rush hour traffic I use the automatic shut off for fuel economy, other than that I leave it off. No issues. Goes to the dealership for all service, recalls or software updates. Not a issue & I’m at 27,000 miles. 🇺🇸
Love my Civic CVT. I have gotten 5.2 liters per 100 km on the highway (45 mpg).
I can ride my motorcycle if I want to shift, but in stop-and-go traffic I want my CVT.
If CVT is too good; I dare you to own a WRX with CVT!!
That's an example that truly doesn't make much sense, and I'll hand it to ya. The manual WRX is lighter, faster, cheaper, get's better mpg, and obviously is more engaging.
That's not a race car. It's a rally car, of course it should have a manual. Track times don't matter. I'd be interested to see a CVT on a Ferrari though.
+Engineering Explained the subarus cvt, especially with the power of a wrx just makes the car seem sluggish and dull
There is a reason it has to be banned in F1. Less engaging for sure, but all you care for the race is the lap times.
+Engineering Explained you'll get your hand on a car wrx and a forester xt and let us know what you think.
I like CVTs
I have a 2016 Nissan Maxima SV with 100k miles, and mostly highway since i purchased it last year with 35k miles on it. Again majority highway miles, i get on average 33 mpg highway, 29.3 mpg overall. I've done all my maintenance to the T and I'm loving it. Don't get me wrong, I'm still hoping it'll survive a couple of more years now that I'm not going to be driving no where near as much as I use to, but i can say that at least in the new Maxima's, if you take care if the car, and not in a city environment all of the time, it's a fun car to drive and stays smooth.
The mechanical CVT was invented in 1490 and has been used in cars since the late 1800s. They are theoretically the perfect match for internal combustion engines. Internal combustion engines of all types are most efficient when pressures are the highest, which is near maximum torque. As you pointed out, maximum acceleration occurs at maximum horsepower, thus the vehicle could always in the right gear with a CVT, regardless of the required output shaft speed. The main reasons they are not in widespread use are:
1. The high-wear and less reliability of the variable drive system.
2. The variable drive system is inefficient in and of itself.
The one most commonly used is the double-pulley system because it is lighter and less expensive. The reason the desire to pursue CVTs in the automotive world has faded recently is the advent of the 6+ speed electronic automatics, where you get the torque multiplication of a torque converter on the low end, the efficiency of gears over the remainder of the range, plus maintaining the engine at an RPM that results in overall greater efficiency than a CVT. Additionally, the advantages of the CVT with regard to simplicity are more than offset by the requirements for more expensive components. Stepped cones and chains have been tried to overcome some of these inefficiencies but they had too many reliability issues. While Nissan has broken a barrier by making a semi-reliable CVT for a 3.5 liter engine, class action suits are not in short supply. Simply put, CVTs have not been cost effective, have given those who implement them a bad name and massively expensive to warranty, and now no longer are the most efficient to be used in cars.
so where does this leave the general driving public given the fact that most car makers use CVT in their vehicles?
I think high end sports cars should be offered with CVTs with options to either run it in a "DCT emulator" mode where it "shifts gears" and a "sport mode" where it always sits at max power.
I think that is actualy a good plan, I don't see why it wouldn't be possible for there only have to be two presets in the CVT's computer. (don't know if it has its own computer or that it runs on the ECU)
mr id Yeah I mean I won't pretend to be some expert on automatic transmissions, let alone CVTs. But I feel like it could be a viable option, especially in supercars or high end sports cars, they should be able to make it work. Then people could get the classic sound while driving on the streets and the fastest possible track times when they'd like.
I think it has to do with how much power is going through it, but the people who tell me that aren't engineers, just car guys
uptorest High amounts of torque wouldn't work with the current CVTs, but they could make CVTs designed for more powerful engines. They just aren't because people don't want them even though they would make cars faster.
Problem is that for high performance such a transmission would get prohibitively expensive because of low tolerances and short maintenance intervals and prohibitively heavy. I know the terminology only in German so please excuse me if I sound like I had a stroke. CVTs in cars work with a conveyor chain, basically not unlike a bike chain except that instead of a chain between two gears you have a chain between two pairs of... errh... Kind of massive discs where one side tapers to a point. And those are spinning at high speeds. Now imagine a bike chain that can transport 600+ lbft of torque between those. Now imagine that this monster of a chain moves at 8000r/m directly below your butt. Imagine the vibration alone. Imagine what happens if the chain might rip.
Doing this kind of transmission to transport such high torques is just not worth it. Remember: "It seems that perfection is attained, not when there is nothing more to add, but when there is nothing more to take away." - Antoine de Saint-Exupéry
Nice! Really well explained. Interesting how the physical control of the transmission is also an emotional connection with the car/truck. Hearing and feeling the engine to decide when to shift is a feedback loop that rewards the driver. That may be half the argument against CVTs. CVTs could be made to remove and replace, instead of repair/maybe.
Does the transmission have any effect on engine longevity?
I always thought that an engine with a CVT might last longer due to running more consistent RPM with smoother application of load on the engine as well as being stall proof
CVT is extremely old DAF invented that whole system pretty much in the 50ts. In europe motorbikes and scooters use these transmissions.
there was a CVT invented by George Constantinescu, that made it into a car in 1923 some details here www.rexresearch.com/constran/1constran.htm
got bought out by general motors, and the idea disappeared into obscurity
DAF called it the variomatic, 1950's up to when Volvo bought the company (last car which had it was the Volvo 340, in the late seventies-early eighties)
and thank God that bI don't live in Europe Make America Great Again!
My DAF 44 would go as fast backwards as forwards, and out accelerate cars with an engine twice the size in town. Back in the late 1970's the fastest production automatic car in the world was a DAF 66 in rally trim, at a mere 130 mph, from a 1400 cc engine.
The only thing better for driving than a CVT is Electric drive. Gears are for the 20th century.
CVT is, by principle, the only way any kind of automated transmission should work. Too bad that almost any practical application of CVT in cars has shown huge issues with reliability over the last years :/
Not to mention all the major parts wearing together and rebuilds not yet a feasible option in most areas, so if it fails you generally have to get a new unit. If it weren't for that I'd probably have a CVT in my garage. Plus the cost... a little CVT for a 2.0L non-turbo Subaru retails about $9100. Compare that to a Tundra's hefty 6-speed Aisin AB60 automatic transmission that new-in-crate from Toyota has an MSRP of about $4400, less than half the cost of the little Subie transmission, and it's not because Toyota wants to sell parts cheaper. Anyone who's ever owned a Toyota knows they don't. If they did they wouldn't list the same truck's 3UR engine at $23k.
Aren't Priuses pretty reliable?
You need to service them but you must use the dealer fluid no substitutes and a quality filter name brand aftermarket no china or best bet dealer. Don't skimp on this service and do at least once a year. I have found that not servicing and not proper fluid is the cause for most of the failures at least with the toyotas anyway. 47 y.o. Trans. Tech. and 2014 corolla s owner with CVT paddle shift.
If they make the belt easy to remove/replace like a timing belt I would totally go for a CVT but until I am confident that at any given moment my transmission won't blow and/or it blowing wouldn't put me back more than a hundred dollars and an afternoon it's a no go.
Good sir you're like the Bill Nye of the Car World.
Very kind words, thank you!!
Well obviously you can't handle all of your salt, so...
I guess an engineer with several patents is a science illiterate buffoon. lol
Giovanni Figueroa got him.
+Andy hoff Don't be mad because you can't tell the differece between sex and gender. The definition of either hasn't changed. The interpretation of the latter has advanced, which it can freely do since gender has always been perceived, and sex is what is assigned by genitalia. I'm sorry you're incapable of advancing with modern society, but overall, that's not my problem. It's also not Engineering Explained's problem. Stop trying to make it ours.
I have been driving SUVs with CVTs since 2005. I have not had any problems with these. I do buy the extended warranty as assurance in case if I have a problem. I like how the CVT works and performs for the type of driving I do. I must admit that at certain speeds there is a bit of lag or delay of maybe a 1/10 of a second or so for response if rapid acceleration is demanded. Once the transmission gets to the proper ratio for the power demand the acceleration and performance is impressive. It is true a CVT can be about 15% more efficient for fuel economy and for performance. Manufactures are starting to use more CVTs in cars except for where a manual shift transmission is required or demanded. Heavy duty trucks and high performance vehicles are best with a heavy duty transmission in manual or automatic type.
Thanks for the video.
I shall read up more, however I was under the impression that we cannot currently build an efficient CVT that can cope with high power outputs.
I drive a stock engine/gearbox Toyota 86 at time attack events. I would love nothing more than for the engine RPM to be at peak all the time; it is always a compromise when cornering.
I've loved CVT's for their theoretical perfection! They have solved the gear problem, and it is CVT. I love it aesthetically, I love the smoothness and efficiency, factors I have tried to optimize with manual transmission, but the CVT does it SMOOOOOOTHly and that gives me driving pleasure!
It would be really helpful in understanding more if you incorporate animation into your videos, side by side explaining the whole concept.
Not speaking for everyone but, not all of us have the technical background (I don't) to understand the calculations (but, I still try to).
Thanks!
Had a CVT in my MG TF. I loved it.
The power (such as it is) is always available.
"ω" is not w (/'d/\b/ /lju:/) it's lowercase omega. ω is the angular velocity
ω=2* π*f(in rpm)/60
Had the 2018 Honda accord with the cvt absolutely loved it.
CVT is the only viable unit for lower output engines .
Infinite gearing is a brilliant idea.
Infinite acceleration!
@@elitesturmgewehr8780 haha
@chris younts snowmobiles have belt drive.
@@Juho999 With a centrifugal clutch I think?
@@sebofo Which acts like a CVT.
7:19 Koenigsegg had their Regera sounds like a CVT with their 'hybrid' electric motor and engine.
Never drove a CVT, my truck is manual v8/5spd. I'd always heard CVT's in produciont are not that reliable?
Correct, they are not reliable at all for a car.
Toyota CVT transmissions are the most reliable.
@@josephmarsh8235 even though they are the most reliable CVT they are still unreliable compared to traditional automatics.
@@RichRusso4218 maybe, but Honda also makes good CVT transmissions too and lots of other transmission's are not as long lasting as manual transmissions
foot pounds, horsepower and furlongs per square inch.
Do engineers still use the medieval measurement system?
220 yards/ sq. inch, wat? TBH metric is a better option but why not use both if you know them?
Yes, and you haven't even touched on the odd ones. Start doing it for US machining and you have to start converting from Metric to SAE to things like Drill Index.
Growing up in public high-school in the US I learned to do science with the metric system. Went to college and on the first day of my introductory engineering course I asked why we weren't using metric. Professor looked at me like I was crazy. I think most scientific disciplines in the US use SI units but many if not most engineering disciplines still use English units.
because metric would be too easy, if you were given the answer right away you wouldn't learn that cars function in multiples of 8, just like computers 8,16,32,64,128,256,512,1024etc. my multiples of 8 are always right there.
+lewinsky hillary Computers work in base 2. Yes you could say a byte still works but, computers didn't always perform operations in bytes.
Can you do a video, if possible, about "What not to do with a CVT transmission." Similar to the video "What not to do with a dual-clutch transmission? Thanks.
what not do with a cvt: send out to a generic garage for maintenance.. cvt's can be bulletproof as long as they get the correct and special oil and NEVER EVER NEVER!! get even a drop of generic ATF fluid or any other lubricant/oil in them.
also the shifting (which isn't real shifting, just forcing the plates to move or stay) gives for extra wear on the belt and plates. if you could hack the cvt ecu and delete the whole shifting thing your cvt could outlast your engine.
also CVT's don't take hauling heavy trailers very well..
Had a Nissan, hated the CVT but I did love it only when I put the acceleration on heaps. It really did get up and go. I mean it was right in the right torque zone. Watch the fuel gauge. Rest of the time it bogged down and was wanting to drive boring. Maybe there was something wrong with sensors etc. Sold it. Now got one of those dual clutch six speed in a Kia now. Sport mode seems to keep the torque there on hills etc. It's good and changes gears almost instantly. I could never do that with my left foot and right foot co-ordination. Don't thing any human could. My preference though is still the torque converter and planetary transmission with a locking torque converter. I know, these days it's all to do with fuel consumption and we don't have options.
Where is CVTs for Dummies?
Search my channel for CVT, I have a video explaining how they work. :)
Engineering Explained
They call them scooters; two wheels, and the feet are in front, like in a coffin.
Mark Kelly they cost you the same to buy but cost the builder a fraction of that to manufacturer and you're going to spend ten times more in labor cost because the cvt are in the shop quite often and they only get about one-quarter of the lifespan of a regular transmission
CVTs are definitely for dummies.
but CVT run hotter than any transmission + it makes the engine run hotter too, way weaker than any transmission and so expensive to fix if something went wrong. most of these reasons effects the engine lifespan which the major component of any car!!!
that way me and every human's hate CVT
That and I like shifting gears. Gears make life better
true but no one has even considered developing on for race or consumer fast road applications, and those problems you mention can be engineered out. remember, the IC engine was never perfect to begin with and to this day, is continuously being improved and fine tuned.
from the look of the thumbnail a CVT seems pretty simple. I wouldn't be surprised if there would eventually be a aftermarket company that would replace CVT internals for cheap. it seems even more simple than manual transmissions. also the reason why it's expensive is because it's new.
Exactly. People said the gas engine was too dangerous to mass produce because EXPLOSIONS!! Air bags were too dangerous to produce because EXPLOSIONS!! Electric cars aren't a step forward because them and their batteries are being manufactured using COAL!! Now Tesla is working on completely solar powered plants in the future.
Where there's a will there's a way!
+David McClelland but where there's a way theres an EXPLOSION!!! HAHAHAHAHAHHAHAHA!
This is a very informative video. I used to work for nissan and wondered why thise cars picked up speed so quickly
Andres Flores A Nissan March kept beating my stock E46 from traffic light to traffic light (basically an accel from 0 contest)... Although I only revved up to like 4,000 before shifting.
Thanks. I love my CVT-driven car now more than ever.
Shitting on CVT is the hip thing to do. It is almost an unspoken rule how no car guy can ever admit the Toyota Prius is a cool car.
...Case in point
ThePatUltra well as a car enthusiast, I would say the Toyota Prius is really cool car, not just for the looks,how it handles. Obviously slow but who cares, it's more cooler to modify a Prius. And trust me, there's a lot fans out there that loves to modify a Toyota Prius. Mostly in Japan then here in the US. I would love to do that.😎👊🏼
It's sadly just not. It's an over styled, underpowered economy car. It's natural habitat is in the left lane blocking traffic.
Obviously there are plenty of people who don't see "coolness" the way we do. The eCVT is central to the efficiency (which is what makes it cool to practical people) of the Toyota hybrid system. The engine in the Prius is an Atkinson-Miller design: it has an approx 8:1 compression ratio with a 13:1 expansion ratio and that is done with intake valve timing (miller). Miller engines are wonderfully efficient in a very narrow rpm range, and the eCVT does just that - it keeps the engine in the most efficient range as much as possible.
As far as "coolness" goes, I owned a Lotus Europa S2 (the older one with the Renault engine) for six years in the mid 70's. It was amazing to drive but a nightmare to own. To me coolness is defined by meeting my actual needs, not my desire to be thought of as flashy and hip. Even my first generation Prius gets me where I am going every time, taking snow in stride, and that is cool.
"Underpowered " is in your mind. The 0-60 time of the third and fourth generation Prius is about the same as the 0-60 of the DeLorean DMC-12.
I liked constant RPM CVT transmissions. They were really good when calibrated right, just misunderstood. I particularly like how i can cruise all day just above idle, or floor it in sport mode and sit at 4-5K RPM and go really fast for my engine size.
So they don't make proper CVT anymore? That sucks.
Lol i have a cvt nissan versa and i honestly love it, just makes me imagine how it looks in the transmission
From the seat of a frustrated physicist, I enjoyed this informative CVT tutorial very much. "Some people" dis CVTs, but it is clear (to me) from this tutorial the current trend toward auto transmissions having more and more gears while coupled with dual clutches...gets closer and closer to a CVT transmission in practice....or didn't you say that in the video! LOL!
I believe the CVT is a dutch invention by DAF, they made cars that could drive as fast in reverse as forward.
They actually did reverse driving races with them in the seventies and eighties, you could find videos if you google for them.
Dot Matrix k
I'm dutch and this is right
Nash had a car i think the metropolitan that had 2 shifters, one for forward and reverse and the other to shift gears go as fast backward as you could forward.
Anyone hear that fart at 3:31
Is the 'w' a lower case Omega? I would think so.
Yeah. Lower case omega is physics notation for angular velocity
here is the letter---->ω
My high school physics teacher nicknamed it "spring break"
I drive on daily basis a car with a CVT transmission, is 17 years old now, and it's mine from 4 years.
I simply LOVE IT!
If you wanna the comfort and economy for a combustion engine, CVT is awesome. Only one thing, CVT needs to be correct exploit and serviced at the right intervals of time (or distance) with right oil and filters and they last in time.
As a fact I was manager of a rental car company with a fleet of over 3000 cars, manual and automatic transmissions, all cars new from factory... I never find a more comfortable or economic transmission in that fleet of +30 models from various makers.
You should really think about doing TH-cam full time, sure you'd make more money than at a job, your ideas are awesome, and there's endless stuff for you to make videos, thanks for your work putting these videos up, sure it's a lot of work. You can even hire people to get more videos out which benefits us, and doesn't hurt your wallet.
he does, he quit his engineering job to do this.
This is my full time job, glad you enjoy it! :)
+Engineering Explained I love your show . but i don't like my cvt but it's not a sports Trans so I guess that's why it's a slow shift
+ras 47 what car do you have?
3.6 l Malibu
Explains exactly why Christian Von Koenigsegg has gone for the Direct Drive (modified CVT) for the Regera.
That's not a CVT at all, the Regera has a single hydraulic coupling as a transmission.
Direct drive is based on a torque converter, totally different
The only downside is...can a CVT actually handle 475 lb•ft of torque reliably?
eventually it can, you used to not be able to have cvts above 150hp but we have cvts pushing over 350hp today. eventually they will get there.
mmm I would think not...
EXACTLY! They are not robust enough for high performance! A modified Vette or Mustang, etc., can make 600-700lb/ft torque and would destroy any CVT
+unbearable pain - CVTs have been developed for F1 (and subsequently outlawed), so yes they can be built to handle the torque and stresses of high performance applications. As he said, the biggest holdup is customer acceptance. No one wants to hear a Ferrari blasting down a straight away while the engine wails are a constant 9000 rpm.
+Phu5ion you have to remember F1 cars don't have nearly as much torque as say a corvette, they usually make it in the 200 to 300 range
CVTs are technically laudable but in use with its “motorboating” characteristic a CVT turns a car into a driving appliance. Not everyone’s preference.