Liquid Piston Rotary Engine - Yet Another Engine That Changes Everything?
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- เผยแพร่เมื่อ 1 พ.ค. 2024
- A rotary Wankel engine consists of a triangular rotor spinning inside an epitrochoid housing. A liquid piston engine consists of an epitrochoid rotor spinning inside a triangular housing and this makes it better in every way.
So today we will take an in-depth look at this engine, we will analyze its benefits, its drawbacks, we will compare it with traditional piston engines and Wankel rotary engines to measure it’s potential to change everything.
If we observe the animation of the engine in operation we can observe that the Non-Wankel X engine which has a fundamentally different thermodynamic cycle, architecture and operation completes three combustion events for a single rotation of the rotor and does intake, compression, combustion and exhaust. Just like a Wankel engine.
Is this nonsense? It’s not and that’s because the inverted geometry of the x-engine enables it to overcome a major limiting factor of the Wankel engine. Kenichi Yamamoto is the father of Mazda’s Wankel engine, he is the man behind Mazda’s inspirational endeavor to make Wankel engines viable for mass production and in 1981 Mr. Yamamoto wrote a book called the Rotary engine. In this book he discusses and calculates the compression ratio for Wankel engine. And it turns out that the practical compression ratio limit for a Wankel engine is around 12:1. This limit is a consequence of the geometry of the Rotary Wankel and the resulting shape of the combustion chambers. This compression ratio limit also limits the maximum efficiency of the Wankel engine and it also makes a diesel Wankel rotary unfeasible. Yamamoto’s calculations stand as correct more than 40 years later because Mazda’s latest and only currently produced rotary engine which is used as a range extender in the MX30-REV has a compression ratio of 11.9:1
But the different geometry of the liquid piston engine means that it does not have a compression ratio limit which means that a diesel version is possible and that’s exactly what the liquid piston has done with their XTS-210 engine, which is a compression ignition version of their design.
But the unique geometry of liquid piston engines enables another benefit, which is the main source of the engine’s potential for improved efficiency. And that is a piston-less implementation of the Atkinson cycle, Liquid piston calls this a High Efficiency Hybrid Cycle, because obviously this sounds far more sexy for marketing and investor attracting purposes. But in reality it is a pistonless Atkinson cycle.
The entire premise of the Atkinson cycle is to have a greater expansion or combustion stroke and a smaller compression stroke. A compression stroke saps power whereas a combustion stroke generates power. So if we create a greater combustion or expansion stroke than we give the engine the possibility to extract as much energy from the combustion as possible which means reduced energy losses and improved efficiency.
Liquid piston engines have resolved the compression ratio limitation of rotary engines but they have not resolved the apex seals. The x-engine still has apex seals they have simply changed location. Instead of being in the rotor they are now in the housing. Liquid piston claims that this is a significant benefit because the seals no longer have to withstand centrifugal forces. According to a technical paper they wrote their models show a blowby reduction of 35% over a traditional Wankel however liquid piston believes that ultimately they can achieve around 65% blowby reduction compared to a Wankel. This simply is not enough for a truly widespread application in many different markets.
But the real problem with lubrication is with the crankshaft. Because air comes into the engine through the crankshaft it means that we cannot expose the crankshaft to a constant oil bath or even pressurized oil. Instead, as we can see from their how it’s made video, the engine uses sealed bearings instead of lubricated journal or ball bearings. In terms of longevity this is an inferior solution and this together with the apex seals is the reason why even the mature design of the engine is only expected to last 1000 hours between rebuilds.
So overall, this is no doubt a very clever design and I genuinely like the reverse Wankel idea of the Liquid Piston Rotary Engine. I’m also sympathetic of the fact that new engine designs need to claim very widespread potential applications to attract investors but outside of a few niche applications, where this engine will likely excel and offer genuine benefits, I personally don’t see a lot of potential for widespread use.
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#d4a
00:00 Working principle
03:06 Rotary Diesel
05:27 Pistonless Atkinson
08:07 Power density
09:53 Apex seals
11:11 Lubrication issues
14:08 Efficiency
15:52 Torque and VVT
17:18 You're in the Army Now
#d4a - ยานยนต์และพาหนะ
I’m a big fan of rotary engines and the Liquid Piston engine intrigues me for being a clever way of putting the Atkinson cycle into practice but I agree with you, it still needs improvements to become something that is universally better than the piston engine.
At least i see that it's inherently better and certainly the design can be improved a lot. Unlike wankel👍
Hey man! A big thank you for watching and dropping by 👍👍 Watched many of your jet engine related vids and loved them!
It looks like a very promising design for the dirt bike industry, as longevity is a much smaller consideration. Many riders rebuild their engines after much less than 1000 hours, especially racing.
The power density, low weight, and relatively simple construction would be very convenient in a high performance engine for dirt bikes. And rebuild/overhaul may be easier due to the fewer parts.
Plus, they sound amazing which tends to be popular in motorsports.
Admittedly, the low torque could be detrimental, but gearing would likely be enough to compensate for that in such a light weight application as dirt bikes.
@@prabowomantoro3945 Inherently better apart from not being able to lube the crank.
Thats a bigger drawback than an elephants fore***n.
The potential does seem there though, and it has more use cases still
Was optimistic about this engine for a while, but just like Achates Power, they unfortunately seem to have become one of the countless entities that promised to "change everything" but ultimately delivered little or nothing.
I agree. Knowing that d4a is a self taught TH-camr makes me look at things like this now differently. This one and the one cycle motor are not realistic for most people if they ever come for sale.
Just because an product/idea goes nowhere, has nothing to do with the value of the idea.
I mean I think you have to consider a bit broader view of these things.
Any new engine has to compete with the already existing units that have absolutely insane amounts of cumulative development spending behind them.
So already from the get go it's super hard to be competitive. However many of these concepts such as for example the Achates double piston engine should be able to be competitive. The issue is just that due to all that EV nonsense it's totally uninteresting, unhip and also not supported by the state to invest into anything like this.
If you ask me, we first need a resurgence of appreciation for combustion engines to set the plane to actually get people to build and invest into these new concepts.
I agree. All I see of this engine are adds seeking investment money. Same for that Aptiva solar EV car. The production date is always a year away.
And this engine is no different. Pipe dream..
Finally, an analysis of this engine that doesn’t feel like paid marketing, nor is a video just crapping all over it because it’s different. It was great to see someone actually gather all the numbers together and go through them in a comprehensive video.
I’ve followed this engine for a while and knew something had to be up with the engine for LPI to have been stuck in ‘development’ for so long. Thanks for pointing out the longevity and efficiency figures as well as the most glaring weakness in the crankshaft.
This dude shilled for many other products, this is just one that he bothered to actually look at.
@@a-iz4pg I usually criticize video's pretty severely but you seem to be making unfounded comments?
D4A has been overenthusiastic a few times ( which I have commented on) but pretty sure he's not a shill.
@@1crazypj Except for all those times he was which kills credibility.
@a-iz4pg Name them please. Some of us might want to look and make our own opinions.
@@ChevyConQueso I was wondering the same thing but didn't want to look like a 'fanboy' 😄
I very much appreciate how you talk about both the ups and downs, instead of focusing on one or the other. Whenever I hear of a new engine technology, I'm always excited to hear your views on it because of your balanced and fair analysis.
I second that. Way too many YT channels just excitedly repeat all the nice things a company's press releases say about their new product (that needs funding and buyers), with absolutely zero critical analysis.
One added benefit over the Wankel engine that I don't think you addressed is that it heats up more evenly. One of the problems with the Wankel is that it only fires on one side and will shift and deform because of that.
Don't know if it's a realy problem, but that x-engine is inverted Wankel engine, so only one side of a piston is opposed to combustion stroke and is heated more than another.
@MaximusU76 - even though only one portion internal rotor face is a "combustion surface", the rotor functions as an intake runner, which facilitates a considerably more uniform temperatures. Also, diesels bleed off about half the surface temperature per kw/hr load because they're more thermally efficient.
@@driverjamescopeland Maybe.
except that the rotor has a hot side and a cold side
The heat distribution problem is inverted:
A Wankel has even heat distribution around the rotor (because all faces go through the same cycle) but uneven distribution around the housing (which has distinct areas for each phase of the cycle).
The X-engine has even heat distribution around the housing (because each of the three chambers goes through the same cycle) but uneven distribution around the rotor (which has distinct ends for intake-exhaust and the for compression-power).
This the most comprehensive and realistic explanation of this engine. In the end, the same core defficiencies will doom it to the wankel’s fate. At this point, it is diificult for any “new” internal combustion design to out perform existing ic technology that has the benefit of over 100 years of progress.
Is the last truly unique mass market combustion engine, the gas turbine?
@@Appletank8 probably, but the discussion here is about car engines. Turbines were tried in the 50’s and 60’s and didn’t work out for land vehicles. They definitely would not meet emission standards now even if the other problems were worked out.
@Appletank8 it kinda maps the same as warships, they went from steam piston engines to steam turbines, aircraft too went from gasoline piston engines to gasoline turbine engines. I feel like pistonless engines other than turbines are just re inventing the wheel by putting feet at the end of spokes...
Nah man you can do anything with US military funding 😎
@@Appletank8 microturbines are gaining interest again, and for good reason. Turboshaft engines can be tremendously efficient and incredibly power dense, but making a muffler for them is damn near impossible. Some guy put a boeing turboshaft in a Miata and gets like 70MPG with it, but it sounds exactly like you'd expect a Miata sized Boeing to sound like.
This channel is so important. No shilling. Just factual observation and simple technical translation in a consistent manner with no fluff.
Interesting thing to note: this basic layout of engine actually appears in one of wankle's papers demonstrating possible configurations of rotary engine, the reason being that both setups actually use the same math just applied to the case vs rotor. This means that if they wanted to pretty much anyone could build an engine of the same layout as the x-engine so long as they use a different rotor design.
The diesel may be better in a uav due to higher efficiency resulting in longer loiter time, and not having to shield electrical noise from the ignition system.
Hmmm true, good point
There are still injector coils. I'm not aware of any purely mechanical diesel injection system that can keep up with target RPM for this engine.
the diesel version should be able to run on road diesel and jet A. The military isn't going to want to carry around a few jerry cans of pump gas just for this
But compression ignition with diesel means you get loud diesel clatter and smoke. You have to remember, this engine still needs to burn 2T oil for apex seals like a conventional rotary. The enemy will see you from a mile away because of the smoke trail . Maybe UAV with this engine can be used to spray pesticide for agricultural use, or maybe mosquito fogging , but not stealthy enough for military use.
Are non-ignition engines safe from EMP attacks? @@d4a
Thank you for the well prepared video ! Big kudos for having also very committed community who are willing to watch 20 minutes with enthusiasm and a lot of comments 😊
This channel has taught me a lot, I am proud of the fact that when they said the crankshaft supplied the air mixure my first thought was "that's not gonna mix well with lubrication".
First time I've listen to one of your videos and I must say that I am impressed by the in depth coverage as well as the pros/cons presentation.
This is the best video I've seen yet on the X-Engine, bravo!
I was not aware that they were trying to shove air through the crankshaft, I had just assumed there was a divider in the center of the rotor so they could push air in one side and let exhaust out the other. That seems like something they're going to need to fix before they can make much progress on commercialization.
I understand the amount of rotor surface area that's exposed to combustion poses a big heat management problem and makes it challenging to turbocharge. Of course if you could turbocharge one of these then the power/weight would be up into the turbine realm and even 30% efficiency would be a huge win for aviation.
They already have a turbo charged 2-cycle, the XTS-210.
Good idea using a divider in the rotor center
For the (sealed) Crankshaft Support Bearings, you would hope that these Bearings have been filled with High Temperature Grease - when operating at those temperatures. The 'normal' grease in many bearings would simply 'run-out' very quickly, leaving little or no lubrication. Mind-Blowing how this guy can study all engines in complete depth, and even their shortcomings in design. I'd like to know what car he drives.....because it has probably got the best-designed Engine!! Greetings from Australia
It would need oil- circulating oil which lubes and cools bearings and other super important parts
❤ MR2
The problem is less lubrication and more heat build up. Using sealed bearings and with no cooling available there is nothing to cool the surfaces so there is no way to control heat. That means either massive tolerances - which leads to massive wear and innefficiency - or as it seems here a need for replacement every 1000(!) hours which in reality would be a lot sooner especially if it was heat cycled often as most car engines are a couple of times per day.
I don't see why forced oil lubrication / cooling couldn't be used with this design via using 2 oil seals per side and using a feed and outlet port from the housing into / out the bearing?
@@Samqdf Have a think about the complexity and amount of sealing pieces it would rely heavily on. Then remember we're talking about mass production tolerances.
The failure rate would be through the roof.
Great tear down and analyses of these engines. Just love clear language and no annoying back ground audio. Thanks, 5 Stars.
Thank you for a very level-headed breakfown of something that the media tends to oversell.
Really love the work and the good engineering approach to these subjects.
“So what I need you to do is machine a hollow crankshaft so I can use it as an intake”
*machine shop door slams
Norton did it with their Wankel engine in the 1980's, nothing new
@@1crazypj How’s Norton doing today though? Just because something can be done, doesn’t mean it’s good for business.
@@rightwingsafetysquad9872 You missed the point, they used a hollow crankshaft because it actually worked but spent too much time and money they didn't have.
If Norton's had not been so expensive trying to recover costs they would have sold more and possibly kept going.
Margaret Thatcher did not want ANY motorcycles on the road in Britain so refused to help (unlike reagan in USA with Harley)
Major problem was Norton relied on Police contracts with bikes that were terrible for low speed escort duty, they were fast though .
@@1crazypj That was exactly my point. I didn't miss anything. I just used fewer words to say it than you did.
They will hype this as much as possible, Then it will disappear 🤣
I think this is past the stage of quickly disappearing as they got very significant funding from the Army. Doubt it will go mainstream in the foreseeable future but for niche stuff it's definitely interesting.
@d4a - they only got funding from DoD and DARPA for drone engine research, range extenders/generators.... and they're still having the same problems they've always had... primarily sealing issues and low duty cycle. The only way to make this engine work reasonably well requires exorbitantly expensive materials.
That unfortunately seems to be the ongoing theme. The delta design opposed piston shown several years in an F-150 seems to have disappeared
I think it will disappear, as far as we on here are concerned. Then it'll pop up in the news in 10years, that some silent drone was shot down in Chinese airspace and we'll say..."I wonder if it has that liquid piston engine thingy in it??"
@@davidjernigan8161 - to be fair... doesn't Cummins offer the opposed piston diesel for some applications in unregulated countries?
I'm into paramotoring, ultralight form of aviation where we carry the motor in our back. What we want: absolute most power out of least amount of mass and space. Also, as we have "a lawnmower" in attached in our backs, it is nice if it does not vibrate that much. The drawbacks of the liquid piston would not be problems in this sport:
- *Longevity:* Our current two stroke engines last ~300h anyways before full rebuild. Something like 1000h would be a dream
- *Torque:* Propeller does not need it
- *Difficult to mass produce:* Our current motors are hand crafted and expensive anyways.
- *Poor emissions:* Haha lol, not on list of priorities :D. The paramotor is practically a large fan that blows the fumes away from self anyways
As nice as it would be I bet their described weight doubles at minimum once a clutch, battery, reduction drive and cooling system are added
I always wonder instead of a passive apex seal, couldn't you use a piezoeletric actuator to maintain seal without lubrication. Given in regular piston engine, the gap between cylinder and ring is around 50 microns. A typical piezo actuator has travel length around 100 microns with resolution around 0.5-1.5 nanometer and response time around few microseconds. So you could have a active apex seal that continuously monitor the distance between rotor and stator and maintain a few nanometer gap without lubrication, thousands of times per second (0.5-5 response time, so about 1mhz position update frequency). In an active seal system, it also solve another issue where uneven heating of the engine chamber create larger gap, since the actuator seal will just compensate for thermal expansion and increase the travel distance. Piezo actuator is pretty cheap too, around 4-5 bucks each. So cost shouldn't be too expensive.
Modern HDD hard drive use such piezo electric actuator at its magnetic reader head to maintain the nanometer gap above hard disk. The reader head actuator can move at insane speed with equally insane acceleration while compensating for thermal expansion of the disk time in real time. And it's done at a commoditized price tag. Similar piezo actuator technology should be able to transfer to apex sealing environment to maintain a way smaller gap and needing much less or no oil. Since the tolerance for a hdd drive gap is way smaller than a piston ring gap.
now add wires.
add heat.
do it 200 times a second.
sensors. connections. interfaces. software. hardware.
this was apex seals right? mounted in a rotor? that spins on bearings? and then spins on an eccentric that also spins?
keep wondering ;)
This seems possible, PZT (Lead Zirconium Titanite) which is most common, has high temp resistance. Especially if the actuator in question worked in conjuction with a simple analogue circuit.
As always, spot on. Great explanation. I am a mech designer, with some hobby affinity with engines. For my dad it was his life. He would have enjoyed this a lot!
It is an art in itself to explain complicated things simply. You 've got it!
I think it's my standard comment at your vids: 'When I think I know it all, something clever and new comes up." How interesting and what a clear explanation again. Thanks!
Thank you so much for going over this. I had seen videos on this engine for a while and had only seen videos either from channels that discuss new tech but dont do any real technical review, or channels who work directly with Liquid Piston on the videos and as such dont push much on the feasibility of the engine.
Thank you! Been watching this for years and was skeptical. Glad someone finally looked at it with a critical eye.
Dude just keep doing this! thank you for everything.
I love watching your videos. Your way to explain complicated things with all the graphics is just awesomme. It helped me a lot. Thank you!
Thank you once more for analyzing the thing better than anybody else here.
Thank you so much for making this. If this, and other new engine designs do nothing else, they do show that human ingenuity and inventiveness has not yet stopped, also with the 'improvements' to conventional internal combustion engines. Interesting times!
really very well explained, good job, keep it up!!!!!!!!
You always have so many things right, never mind about the outro being a bit wrong! Thanks for your crystal clear explanation!
This dude is an awesome teacher.
Truthful and to the point.
Always enjoy your videos.
Thank you.
I already have an engine design that does all the stuff this does even better with a lot less parts. I'm still working on the emissions issues, but it should be exceptionally good on that regard as well. This concept is interesting though. This channel always provides some good new things to learn.
never expect peanut shaped piston will as good as this before.
I waited for you so long to do this video, finally made it congrats man!
I was waiting for the seal and emission problems to come up. Thank you for the great explanation.
So that's not a dorito, it's a... peanut?
Superb video as usual, had no idea these were a thing!
You're a legend kind sir! Thanks for the video :)
Extremely interesting concept and I believe you have accurately predicted its future. As always the speed, clarity and accuracy of your presentation is superb. The text of your presentation caps it off, allowing time to absorb the subject in depth. Many thanks.
This does sound very useful for military applications. Definitely very compact, and if it is quieter, that’s also a nice bonus. On the logistical side of it, you can ship a bunch of them out, and pick up the broken ones at the same time, and you’d just need one state-side facility to take in all the spent engines & rebuild them & put them back in circulation.
Maybe also could be useful for camping or wilderness trips since it is so small & light, but the reliability becomes an issue then.
Very interesting little engine.
I already mentioned this in few videos. In Finland moped is defined as no more than 50cc and around 5hp well as cant move faster than 45km/h. Since we have engine size limit and changing gear ratio's make first gear ridiculously slow with high torque and make engine in 5th gear scream, or 1st being with out torque and 5th gear being reasonable, low capacity max50cc, high torque diesel would be ideal and its easy to limit mentioned speed, but with ability to torque trough steep hills and have cheaper fuel source, but there havent been any diesel engines compact enough to retrofit into older moped that dont have emission bullshit. Witch only dirty the engine and eat power. Despite what he said, emissions are not a issue, least when retrofitting engine to older moped and who wants the modern plastic trash anyways? Two strokes need rebuilding time to time and kids tuning them up with out knowing what they are doing, so rebuilding them aint problem ether. Long as engine is light weight diesel with more torque than same size 2 or 4 stroke engine, that can last same as two stroke, easy to fix and rebuild and cheap to purchase, it would be hit. Too bad they are not yet selling them anywhere.
Wankel would be another nice engine, but there too you cant find 50cc ones and even then the larger ones are hella expensive regardless of condition.
I was deeply concerned about that hollow crank shaft before lubrication issues were discussed! That has got to be the most restrictive and problematic path for intake air to travel that has ever been imagined!
That's my concern as well, especially when used in a diesel configuration!
Whilst true there is technically the potentiol to build it with lubrication in there, it will just result in a crankshaft thats larger for the engine output, but i don't think thats an issue here honestly.
rather than the lubrification i'm more concerned about the air temperature the very moment it crosses inside the crankshaft considering it passes side by side with the exhaust gasses and enters a high-temperature nest.
@@Quartolone This is an issue they acknowledged somwhere else when discussing it. Apparently makes it impractical to turbocharge.
@@Quartolone Good point!
The best and fullest explanation of this engine I have seen. I think I now understand how it works. Thank you.
Well you're the first one that pointed out the shortcomings I have been talking about ever since I've seen the design - emmission due to lubrication and longevity due to seal type. I even talked about it in class (I am an automotive teacher in Celje). And you explained so much more!
Incredible video. I know nothing about ICE’s, other than their general theoretical function, but I accidentally stumbled upon one of your videos some months back (🤔 Scotch yoke engine!), and I’ve been hooked. Your explanation and analysis is thorough, concise, well-explained and totally fascinating. Just a winner of a channel. Outstanding work, thank you.
This motor… could it be deployed in a motorcycle…😳 …maybe a diesel bike
Thank you so much for the kind words. Motorcycles are also subject to stringent emissions nowadays in most markets so I doubt chances are high. Plus, current engines are simply very good. You have small and lightweight parallel twins delivering everything anyone could ask for.
@@d4a🤣 Of course, I paused the video to type the comment… and as usual, you are covering it all very thoroughly. As a biker, I can say you’re spot on- he parallel twins today have been able to be efficient, strong, slim and light, and the vibration balanced out enough to be so versatile. Hondas are particularly good; I had a new CB500F, and plan on buying an Africa Twin, and both are fantastic. The V is still the “ideal” for a bike, though… for feel and character. I had a couple of Italian Aprilia bikes that were just a joy to ride for the feel… Thanks again!
The military has been trying to get diesel motorcycles in their fleet for years, the idea being that they only need to have one fuel for all applications. Kawasaki KLR Diesel was the closest they came. Enfield of India tried it too for a while, and as pointed out, the military doesn't care about emissions, so it could be a possibility in the future.
Liquid Piston is actually focusing on investors just like yourself on Facebook. People who are not very knowledgeable about this subject. So I wonder if the technology was so wonderful wouldn’t they look for investors who are knowledgeable about this category of technology?
@@somenygaard If your insane enough to research a new IC engine technology, you take investors wherever you can find them, and Facebook is full of idiots. The US military answers your question, it's a perfect fit for the Xengine, and they aren't idiots.
Xengine? I wonder if they were looking to Musk to invest, if so they are idiots.
One thing I remember hearing about the Wankel is that because insurance is/was calculated based on displacement, there was some disagreement about displacement definition on a Wankel. One side argued it was the entire chamber, the other side argued that it was only the third that did the combustion. The former side won, so the insurance was WAY too high for the fun factor and it turned people off.
With the geometrical inversion of this design, that displacement definition matches the power scaling and would assuage that.
Excellent overview, as always. Superb research and presentation. Keep up the good work!
Ive looked at just about every other sites descriptions of this intriguing engine. Yours is by far the best, including the logic of the 'liquid' piston, which I looked everywhere for the reason for it. Thanks
I usually don't say anthing but I wanted to say: I love your insight on these emerging engine designs! Keep up the good work!
Another problem with this engine is that it can not be stacked. If you want a bigger Wankel rotary engine, just stackmore and more rotors. With this engine, that is not really possible, as the all the intake air needs to come through one small hole in the crank.
Intake could be routed through intermediate plates, just like Wankel. Central exhaust is why they can't be stacked, because you can't put that much heat across the sealing surfaces to move it outward.
LiquidPiston themselves have claimed they can be stacked up to 3 rotors. They haven’t explained how they would do this but I’ve personally asked them and they confirmed it is possible and they hope to explore this further in the future.
They said we would never put a man on Mars
no i think you can stack them just fine. stack 2 rotors and each one gets air from one direction
I quite agree on this: two is the practical maximum.
Looks like a good candidate for the air compressor head - quiet and with good heat dissipation, also no issues with injecting oil. Would stand somewhere between piston and scroll compressors.
i think that place is already taken by some other semi thorid engine. also this one would have problems with oil
Wow. Thank you for this amazing coverage of the Xengine. I knew their claims were too good to be true, but didn't have all the details to explain it, and you have covered it fantastically.
Fantastic explanation as usual. Thanks for making these videos they absolutely rock.
A lot of motorcycles use ball bearing cranks granted they usually are not sealed. I think it would be perfect for a bike and if the bearing is easier to replace I would take that tradeoff. My dirtbikes require rebuilds a lot more frequently than you'd think.
I also think diesel being used as the primary fuel would also allow the side seals and apex seals to last a lot longer than gasoline because diesel is a lubricant.
Unbreakable apex seals have been a thing for nearly 15 years. Driving 4 answers is just misinformed.
@@caboose22320 the issue is less about apex seals breaking and more how reliably they actually seal the chambers off from each other, and lubrication issues. The Wankel has a problem in that the ignition port will almost always leak some air through, and the side seals still aren't as good as piston seals.
@@Appletank8 this is it... a piston ring just oscillates, and only "seals" during combustion when its forced down and out.
an apex seal is getting hit with intake vacuum on one side, combustion on the other, or combustion, exhaust, or whatever... never a constant predictable force but a constant change from tilting one way to tilting the other... same nasty approach angle with teh wall of the trochoid itself... side seals have massive sliding frictions, and again, nothing in a rotor has that simplicity of a piston ring being ASSISTED by combustion pressure to seal...
i say it again. the only TRUE "liquid piston" is a humphrey gas pump. dont need rings or bearings when the piston is water!
Wankel is a Dorito spinning in a Peanut.
Thank you for being realistic and thorough about these things, instead of just parroting the hype to get views.
I love how honest these videos are
45% thermal efficiency might be pretty nice if it also comes with a weight, complexity, and wear reduction. I also wonder how the gas version would handle a turbo.
Or perhaps they could take advantage of the increased surface area that's exposed to the combustion process by having an oversized cooling system, use this engine as an EV range extender, then add a Stirling Engine to extract electricity out of that heat, dump it directly into the charge controller, potentially boosting the engine's thermal efficiency considerably.
I wonder if material science will ever solve the apex seal problem. I know Teflon isn't suitable for this application because of its fragility, especially under heat, but I have to imagine there's some undiscovered compound out there with similar or better friction and greater durability.
Ethically sourced Siamese cat whiskers. Material of the future.
@@MattyEnglandSure
Funny you say that, driving 4 answers is misinformed as most enthusiasts not in the rotary circle are. Unbreakable apex seals have existed for the better part of 15 years now. Just google unbreakable apex seals. Theyre pricy but im 60k miles deep with no issues.
Thank You! In my opinion you have the Best explanations of engine tech in a way that the average person can understand! Detailed, accurate, reliable info! I rate you #1 on TH-cam!!!
I was waiting for this one :) thanks for the analysis, we knew the whole "it changes everything!" was BS, but you quantified it
Could you make a video about the Volkswagen VW XL1 car, and what happened to its promising 1l gasoline per 100km ?
If this engine turns out to be suitable for UAVs it might also be suitable for light aircraft, at least in the homebuilt/experimental category. The acquisition cost would have to be competitive, which could happen if these engines get mass-produced for other applications. Durability is an issue, but since many civil light aircraft spend far less time in the air than UAVs the short time between overhaul might not be a serious limitation.
Love your content and your silent and relaxing style of talking!
You must have some kind of natural hypnotic talent 😶 I sarcastically hate the fact that it is "impossible" for me to either skip your content or fast forward through it!!! Good work👍
I wonder if these could work as superchargers, and how well they could work as such.
Interesting point. Longer axis, and add two ports to the eccentric shaft... I'd like to see how it performs as well.
no well i guess... wankel can work as one but its bigger than actual engine
Well wankels where originally made to supercharge air.
As a aircondition pump.
A mix of a vane pump and a ring pump basicly
I think a range extender would be a beautiful application for this.
Yes. However, the rang eextenders' market is dwindling, we're moving to pure EVs.
@@jakub.anderwald Absolutely! but there could be some niche remote or military applications.
@@jakub.anderwald
No, we are not "moving" to pure EV's.
We are being forced to pure EV's.
If it was left to consumer choice, a plug-in hybrid would be the powertrain of choice.
@@DCBChump regardless of the reasons, we are moving. And we're not moving to EV+range extenders, just pure EV. So the need for range extenders in consumer automobiles will be probably lower over time, not grater.
Thank you for the excellent overview and analysis. I also appreciate you poking fun at the "Changes Everything" tagline. That has become more than a little worn out online :). One small note: A piston engine also burns oil by design. The cylinder walls are slightly cross-hatched in production so that small amounts of oil will adhere to the cylinder wall when the piston is fully in the bore and that oil burns on the ignition/expansion stroke. The amount of oil burned is small enough in most modern engines that adding oil between oil changes normally isn't required, but a bit of burning does indeed happen. A few decades ago the amount burned was high enough that regularly checking the oil level and topping off was necessary. Your conclusion about the likely application of this design is spot on IMO.
As always brilliant, just brilliant. Keep on the good work.
Now, what would happen if those engines becomes hybrid? Sounds like a new engine is brewing.
That longevity issue is a killer but it is amazing that it can work with diesel
Diesel is a big positive, apart from anything else it's a lubricate.
wooo. glad you're covering this. because you provide -super super- high level information
I saw this engine many years ago and thinked why it didn't reach the consumer market. Thanks for you great explanation!
love your education videos from Palestine Also are an engineer ? because you know soo much
What about the apex seals? Will they be as finicky
It's in the video. Apex seals themselves are not finicky it's their lubrication and associated blow-by that's the issue
It should be better because temperatures in new type engine are more balanced. In wankel one of the problems is one side of engine is much hotter than other. However I thnik it will still have much shorter life than piston engine.
Thanks for continuing to tell it like it is rather than how enthusiasts want it to be. There's so much more value in being educated than pandered to. Every time a new rotary engine comes out it's the same song and dance of false hope. They are dead and gone for the applications enthusiasts love
Once again, an excellent, interesting and an informative description of alternative ICE design. By Showing the advantages and drawbacks of the design one can understand what type of applications it would be sutible for. Thank you.
It doesn't matter how good it might be. EU lawmakers will never allow any ICE engine to challenge the religion of electric cars from now on.
Indeed 😅
If the German and French motor manufacturers give the politicians a hard word they’ll listen. This Carbon Zero nonsense has to end its making the western world uncompetitive, which doubtless is the intention. Getting the talking heads who know and understand little in the science and technology sectors on side is cheaper than war and just as destructive.
ICE has had a century of development. It is a highly mature technology. There is little in the way of thermodynamic gains left to be had. That is why.
“It doesn’t matter what” Makes it sound that someone could come along and double efficiency. ICE is about as good as it’s ever going to get.
Not going to happen, physics ALWAYS trumps marketing.
EU is ZSRR-bis and will collapse the same way. It's only a matter of time.
Wasn't the rotary a complete disaster? 😂
Yes but braap
No
Your discussion on this and similar subjects is impressively comprehensive in scope of all relevant considerations. Half way through, when I think you have covered everything, you continue with three or four more points I hadn’t thought of. And just in case you wonder, the occasional bits of levity you sometimes add, are appropriate IMO. Thank you 😎♠️🎩💙
Another very good discussion. Congratulations and thank you!
A very compelling case, well argued and explained about what works, and what doesn't.
Too many sliding surfaces poorly lubricated for me.
Love your videos, your depth of comprehensive coverage is much appreciated.
Your videos stagger me!! You explain such complex information, so simply, I swear my two year old would understand most of it ! Incredible work as always
Yeah, he’s really good at explaining things that we can understand, I wonder what he’s day job is, lecture/teaching?
Probably the 1st video about liquid piston engine which doesn't look like a commercial. It makes me to subscribe for this channel.
Great content! Going into the details about the longevity and manufacturing side, learned a lot. That crank shaft air intake and rotor exhaust seems quite difficult to produce for cheap!
Well done on the video. Your explanation are always very easy to understand... thank you
Another great video, wish you were around when I was studying mechanical engineering in college in the early 80s.
I'm always learning something on your channel, thank you and a great video!!!!!!!
suddenly all kinds of engines pop up from anywhere. can't be that beautiful
Very interesting video. I really appreciate your insights on these developments. Well done.
This explanation was so good you have s a new subscriber. Thank you!
Marvelous! Great video to start the morning.
Comprehensive analysis as usual. Well done.
thank you for the information! I found it is very enjoyable!
Great video. I love that there are still so many ice innovations possible.
thanx 4 the analysis. it solved a problem I had with making a rotary steam engine using Wankel's design.
Thanks for that breakdown. I thought you were very even handed in your comments.
Thanks for sharing.
There was a diesel Wankel engine. My father in-law worked in the foundry that cast it. It used one Wankel engine to compress the air fuel charge like a supercharger and the second engine finished compressing it enough to combust.
That was the Rolls-Royce diesel Wankel design - it ran, but never made it past the prototype stage.
@@brianb-p6586 yep. I suspected it was a leftover design from the Nazi tank design department that was given to RR after the war (as RR was building the engines britan used in most of its war machines and would have been privy to all military engineering spoils)
My father-in-law mentioned it was for a tank but they didn't know more than that. RR was not able to cast the complex housing but Fodens foundry had master craftsmen that said RR was actually casting it upsidedown the whole time and they were able to make a clean casting first attempt. This is what makes me think it may have been second hand engineering, who wouldn't know how to cast their own design?! Ha!
Brilliant analysis, and well presented, thanks.
Very comprehensive, awesome explanation as always
Thanks to this video I've learned that this engine exists, and, at the same time, that I don't need to learn more about it as a regular ar enthusiast. Thanks! :)