If You Understand Volumetric Efficiency You Understand Engines
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- เผยแพร่เมื่อ 2 พ.ค. 2024
- The volumetric efficiency table is perhaps the most important table inside any ECU. Our vertical axis is engine load which in this case is MAP or manifold absolute pressure, in other words this is simply the air pressure inside your intake manifold. Our horizontal axis is engine rpm or rotations per minute. This data can come from a crankshaft position sensor which counts the number of engine revolutions or it can come from something like an ignition coil, the ECU counts the number of ignition coil firings per minute and knows the rpm based on this.
At idle and other low load scenarios inside the intake manifold we will find vacuum, or air pressure below that of the atmospheric air pressure outside the engine. This occurs because the throttle plate is closed and prevents entry of large amounts of outside air into the intake manifold while at the same time the engine is running and the downward motion of the pistons is rapidly creating a void or absence of air above it. The same air is then mixed with fuel, compressed and burned. In other words it’s consumed. So the engine is consuming more air than the throttle plate is allowing inside the manifold, meaning that we actually have less air per unit of volume inside the manifold than in the ambient atmosphere outside the engine. In other words a cubic inch or cubic centimeter or cubic whatever of air inside the intake manifold at idle actually contains less molecules of air than that same cubic inch or cubic centimeter of ambient atmosphere air outside the engine. Because we have less air we have less air pressure, or in other words, a vacuum inside the intake manifold.
But as the throttle plate opens more and more outside air is allowed into the engine and pressure gradually increases, it transitions from vacuum to atmospheric pressure. The engine of course can’t consume the entire atmosphere and therefore the pressure inside the intake manifold becomes atmospheric when the throttle is fully opened. But notice that on our map atmospheric pressure is displayed as zero. Below zero is vacuum. Above zero is boost. A naturally aspirated engine will never go significantly beyond this point whereas a turbocharged or supercharged engine will venture into this area and how high it will go depends on how much boost is generated.
Speaking of what the engine is capable of doing we must ask what do the numbers in the table itself actually mean? 87 what? Well, this is volumetric efficiency of the engine at that particular intersection of manifold pressure or engine load and engine rpm which means that this is not 87 of some unit, it’s 87 percent. 87 percent of what? 87% of the volume of the engine, or it’s displacement. In other words 87 means that 87 of the engine’s displacement has been filled with air. 100% would mean that all of the engine’s displacement has been filled with air. As you know the displacement of an engine is actually the volume of the cylinder and the combustion chamber above the piston. 100% volumetric efficiency means that the engine has managed to ingest enough air to completely fill this space with air. What does a volumetric efficiency of 110 mean? As you can see this occurs at boost, in other words a forced induction device, aka turbo or supercharger is forcing more air into the engine than the engine would be capable of aspirating naturally. Due to the action of the forced induction device the volume of air inside the cylinder is greater than the volume of the cylinder and so the pressure of air inside the cylinder and consequently the intake manifold increases.
What’s interesting to observe is that volumetric efficiency actually starts dropping off as RPM increases. Shouldn’t the engine be ingesting more air the faster it spins? Well yes, but up to a point and this table very accurately reflects the anatomy of the engine. At low rpm we have low piston speed and because the pistons are moving slowly the velocity of the air entering the engine is also reduced so we’re unable to fill the cylinder. As piston speeds increase air velocity increases and we reach a point where we achieve maximum volumetric efficiency. But as piston speeds increase even further the intake and exhaust valves are open for ever shorter amounts of time because the opening and closing of the valves is synced to the speed of the piston via a cam chain or cam belt. At some point the valves are no longer open long enough for enough air to enter the engine and volumetric efficiency starts falling off. The engine simply can’t breathe fast enough to match the rpm.
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excellent videos
Gimme all pawa!!!!
Maybe you make a video about long and shot term fueltrim and what to change or how one can change those to make the car drive more or less economic..?
Can you make video about open loop and close loop tuning and which is the best one ? (also another one tuning oem wideband ecu"s and what's the difference between standalone ones ) (for example MED9.1 2000 era oem ecu for vag group )
thank you for explaining this! a good example is the VW(audi, vw, skoda, seat, cupra) 1.5tsi 150hp with kangaroo behavior. at low rpm and low demand - the engine is forced to keep the throttle open more than it should. so is forced to use the stratified mode in the acceleration phase when it should use the homogeneous mode. unfortunately VW want to have less co2 and made the engine worst. or VW used the same VE as the 1.4tsi, but 1.5tsi has same bore but a little higher stroke, so the VE is little different at low rpm. another theory is that the valve overlap at low rpm is too high (is emulating the EGR, this engine does not have EGR) and the VE is wrong. BOSCH MG1CS011 :)
I accidentally added this to my sleep playlist so for the past week or two I've been randomly waking up this man explaining what a volumetric efficiency is.
That is one way to reall\your make sure you memorize it.
You are not the only one 🤣
I fall asleep usually listening to videos and woke up to this video
Sick pfp btw
Add it to everyones playlist.
This map contains all the fundamentals of the engine operation. It doesn’t matter if it’s car, motorcycle or truck it’s all the same for internal combustion engines. Proceeds to show a Tesla, and a Rivian. Lol. That had me laughing. Thank you 🙏
The bike is electric as well
Me too. I had to skip back to make sure I didn't see something wrong.
@@AirzonesBlasters yeah I thought so but couldn’t tell 100% so I left that one off. 😂
Yeah, the bike is a Zero SR/S.
Ahh, I see you are man of culture as well
This was genuinely the best explanation of VE and Lambda I've ever seen. This put everything into such perspective. Makes me realize an aftermarket ECU might be far less complicated than I initially though to tune for.
❤
I kinda just assumed that ECUs were mysterious black boxes that ran some secret software specific to each car. After watching this video, I now want to learn more about ECUs.
wait till you find out most tuners just make a tune once for a car and use it again every time that car comes into the shop, with minor changes. then after finishing in 10 minutes they wait 30 mins and charge you $700.
One of the most useful tuning videos on the internet today. I'm midway through modern EFIing a 70s car, and I'm glad to see my decision validated here. Wideband, and e-throttle should massively improve emissions and driveability.
or try the carb cheater
Dig it. My forever car will be a 240z with a modern engine.
I hate e-throttle though. I love EFI but with mechanical throttle. With e-throttle, there is always a slight delay the moment you jab the accelerator and the engine RPM begin to rise. This effect is less prominent if you run a CVT gearbox, however if you have a manual gearbox, the rev hang sucks because of the slight delay from the e-throttle.
@@fleurdewin7958agreed, on manual cars, eletronic thottles do take away something from the experience
@@fleurdewin7958 I hate unsourceable ancient Bosch parts more. The hybrid Bosch Jetronik-L system controls anti-stall, idle control, and such are unobtanium. E-throttle doesn't have downsides for my application, throttle position has a delay of less than 50ms (measured on an oscilloscope) which I'm sure is not perceptible in normal driving conditions.
Yes modern technology is great, but explaining this to us is awesome ❤
Engines are almost 110years old technology..
@@Lordosvk and still everything about them feel fascinating
@@Lordosvk What do you mean with "almost 110years old technology"?
I don't know of any "major engine type" that wasn't in operation 110 years ago.
Did you mean "210 years"(Thinking about some early internal combustion engine as the start of "engines")?
@@TarenGarond the first modern internal combustion engine, known as the Otto engine, was created in 1876 by Nicolaus Otto
@@TarenGarond i meant using combustion engines almost evrywhere thats like hunging with stones. even you have modern technologies how to produce food or get the food.
I self learned tuning about 15-20years ago. From dizzy/webbers to dizzy/fuel analog ecu and finally full digital ignition/fuel. I street tuned with innovative wide band and listening for knock . You’ve explained this beautifully. Kinda miss the cold nights on concrete floor tuning days
Tell me how to get the program to tune then. I have a volvo s40 2005 that I want to tune.
@@alanboggs2315its not something thats taught on a TH-cam thread 😂takes a lot of hard days
i dont even know how to begind such life without budget or background in family and without school :/ practice while supervised by other mechanic i suppose..
Where to find that digital dash
What’s the best resource you used to learn to tune i want to tune my own cars and want to get started
You are by far the best at explaining all of the science behind these different tuning technologies. I watched your boost school series all the way through, this tuning series, and so many other videos on your channel. You've given us so much knowledge, and for that, I thank you. I really hope you enjoy making these videos, because you're excellent at it.
Yes I totally agree with you he by far is the best at explaining these complex technologies in a way that pretty much anyone with a little bit of common sense and knowledge can understand I love his videos I use them to teach my son about stuff mostly motor bikes trucks and anything with an engine that we can try an ride lol
would love a tuning series. your videos on the physical aspects/concepts of engines are so informative, and as somebody just getting into tuning from scratch, it would be awesome to see
nice pfp
A tuning series would be awesome!
I tune tons of tuning on my channel. I teach the concepts as I'm doing the tunes.
Agree! Would love to see that too! Would love to better understand how VE Map, LAMBDA target Map and oxygen sensor works and how many more car components work together!!! :) Love this channel.
You forgot to say that even in NA engines the VE can go above 100% thanks to the help of exhaust pulse scavenging combined with valve overlap which helps pull in more air and have more than 100% VE despite engine being naturally aspirated
I was wondering this exact thing! Excellent point. Maybe I am missing something.....this cat is pretty sharp.
Exactly, from what I've heard they can reach VE's as high as 130% nowadays.
The example VE map even showed that. It wasn't mentioned, but the map shown has >100% values under 0MAP.
A ram-air intake combined with a careful designed airbox has helped many sportbike engines achieve greater then 100% VE for decades now, despite being naturally aspirated.
@@Cheezeball99999oh yeah i just looked again and realized now 😅
For those who don't know, it is very beneficial to tune in actual Lambda vs AFR. If your target is 1.0 Lambda and you're getting .9 lambda, you know you're 10% off. Just pull 10% off your VE table and you're GTG. No need to guess and check based on the error and no complex calculations to perform.
Best automotive teacher on the internet 🔥 D4A never disappoints.
Nice touch at 0:42 visualizing how VE map applies to all engines in cars, motorcycles and trucks ; )
Except the car (Tesla) and the truck (Rivian) are pure EV.
@@lewiswestfall2687 And so is the Zero SR/S. It's probably meant as some kind of device that flies over people's heads.
You are a treasure to the car community, sir.
By the way, what is shown at 14:10 is called "Closed Loop Controller" or "Closed Feedback Controller" (it was not mentioned during the video I think) and it is massively used at basically all industrial processes I can think of:
You measure the output of the process and input it back as one of the variables doing the calculation. One of the most common examples of the math doing the magic to let the system know how much to vary the input to adapt to the measured output is the PID Algorithm (Proportional-Integral-Derivative). Even 3D printers use it on the firmware.
Is this the same as a negative feedback loop?
@@abdul-kabiralegbe5660 negative feedback is one specific case of closed loop controller.
@@Gryphus-R Thanks.
@@abdul-kabiralegbe5660Yes, negative feedback loop stabilizes the process, while a positive feedback loop destabilizes the process.
Most (if not all) controllers use negative feedback.
Positive feedback loops can be seen in nature, like the Ferguson effect (in childbirth) or when getting injured and more and more blood flows to try and seal the wound.
@@andreimateescu8997 Thanks.
Perhaps one of the most complicated subjects I've seen you do a video on but paradoxically also one of the most clearly and simply explained. You're a great teacher.
I learned about volumetric efficiency in the 70’s while still at school, messing around with carburettors etc. This video has brought so much enjoyment to me, thank you
the fact that he used full-electric vehicles at 0:40
think that's the point lol...
@@QuincyStick i mean i knew it was sarcastic but like its quite funny where the VE Map is for ICE hahahah
I’m about to buy my first aftermarket ecu and make my first steps into tuning and this video was very usefull and and makes me confident I can do this. Thanks!
As a retired Auto Shop teacher, I want to say that this really hits the mark. I wish I could've had access to this video back when I was teaching.
The mapping and feedback systems are so far advanced from the old school carburetors and centrifugal/vacuum advance ignition systems that it's like a different world.
The funny part is that the principles have remained the same, just that now the ideal values can be achieved, whereas in the 'good old days' we were happy to get close! 😁😁
Keep up the good work!
He just slipped in the images of the Rivian, Tesla, and Zero to see if we were paying attention. LOL!
This is why I love the channel. It’s so easy to understand how a certain part of a car works and how to tune it. I’m learning things about cars that I shouldn’t know at the age of 15 and it’s free too 😅
Brother
Hands down your channel is ABSOLUTELY THE VERY BEST for all things that go VVRRROOOOOMMMM.
I can certainly Tell you this my brother most of us that dropped out of school and caused B.S In school if we had of had you as a teacher I myself would have been 2 hours early for school.
The way you speak and explain you make the hardest most scientific things as easy to understand as putting butter on bread lol.
Keep up the amazing channel.
I'm lucky I guess I am a gearhead and have built a few nice toys but I will honestly say even with the knowledge I have you brother have taught me A LOT.
CHEERS ALL THE BEST
And
THANK YOU!!!!!!!
I really enjoy the way you explain things. I have a good basic understanding of chemistry and physics, but I'm only just learning to be a mechanic. As a bit of an old-timer in age (I'm a 45-year-old woman) but a relative newcomer to this world, something about your presentation style really helps bring these two halves of my brain together in the best possible way 😁
Thank you!
What a fantastic video. After watching a ton of tuning videos, this is the first time it’s all come together in a concise way. This should be the first tuning video anyone should watch.
I so love physics. Good work my man!
This video is a real gem. A huge congratulations and thank you for all these explanations, this channel is really underrated and should have many more subscribers given the quality of the information it provides. Congratulations once again for this excellent video.
This channel is the equal of Engineering Explained channel.
This video was legit the best I’ve ever watched on the matter. Super clear yet in depth, very well shot… All your videos are great but this one I enjoyed particularly. Big thanks for the amazing content, your channel deserves the million subs.
Dude, every time I visit your channel I come away much smarter for it. Thank you. I have two 911's that I feature on my channel. One is a NA 4.0 and the other a 3.8 Turbo S with a custom tune and upgraded injectors. Knowing how the engine works, at this level, is the only way you can really maximize your performance. THANK YOU!
One of the most simple and best videos on VE tables and basics of EFI tuning. Great work, for beginners this is a hard topic to grasp and you made it easy to understand.
Are you planning an ignition map as well by any chance?
Yes, ignition is coming too 👍 thank you
I've always wondered what all those numbers represent to tuners and this is the best and most clear explanation I've ever seen. Amazing stuff. Also love that you used all EVs to represent internal combustion cars 🤣🤣🤣
i was just about to say lol 0:39
Haha, I didn't see that 😂
Thank you so much for the video. Last few months i was reading lots of information about ecu tuning in forums, but your video is so much easier to understand. Good luck and waiting for more videos.
one of (maybe the only one) the best youtube channel about for this kind of topic. I learned a lot from you. really appreciate 🙌
I have found your videos very educational. They are well organized, very well researched, and explained exceptionally clearly. Thank you very much for your hard work.
0:42 I've almost choked from laughing. These illustrations :D
The way you simplified this theme so a dumb like me can understand is amazing
Here in Brazil we have a standalone ECU - Fueltech, that has a digital dash integrated, and does correct lambda up to any %, also has a self learning function that self adjust the map for fuel injection, it helps a lot when only minor changes are required. also you can adjust the maps on the display of the ecu itself. If you can take a look! I always appreciate your videos, very informative, its awesome!
0:42 I laughed so hard! 😂 ..of all the vehicles to choose 🤣😂🤣
had a good laugh that all the vehicles shown in the beginning are electric, appreciate the humor.
This video gives me heaps of confidence as I am planning on putting a Link ECU in my Celica GT-Four ST205 and tuning it myself. Thank you for making it.
Holy Mother of God... This is one of your best video to date ! And that says a lot, since all of them are freaking awesome ! I always looked at these map thinking this was some kind of sorcery, but you explained it so well, it turned on a lightbulb in my brain. Thank you !
why weren't you my physics teacher at school 😭😭
There's so much more to discuss on this topic. Please do a part 2, maybe with wear and tear examples..
Essence of internal combustion, and the Rivian and Tesla images😂. Love it
Thank you for this explainer! I have been struggling with EFI for a while now, I feel like I am beginning to understand it a little bit thanks to your video. Your explanation has clarity and detail that even I can understand! Keep up the good work.
Really great video! I’d highly recommend aftermarket ECUs with real-time tuning for those who have to make major changes to their VE map. Being able to “real-time” change the VE map while the engine is running is a game changer, rather than having to flash a tune, data log, fix the VE, and repeat. Often takes days to do this rather than minutes on an aftermarket ECU haha
cara, seus videos são muito bons, obrigado pela aula!
Please keep uploading tuning content like this, it is so good
I'm almost half way through re-wiring a DSM right now and this presentation will be helpful setting up ECMLink. Top notch videos, excellent display of technical knowledge, and also thanks for not dumbing this stuff down.
"Isn't modern technology great?" He says after having freed himself from carburetors!
Excellent video. Not many good introductions to this topic out there. Especially this quick and digestible.
Freed is a harsh word 😆 I honestly enjoyed them and I feel I would be somehow incomplete without the carb experience.
@@d4a Hahaha I know only picking on you. ;)
The video I had been waiting for years. Very good job!
Always easy to understand even for a 🇨🇵 people 👏
OK brain, strap yourself in, we're in for another D4A workout. 😵💫
Not often that a single video is all I need to understand a topic. This is fantastic! Thank you.
You have a great talent for teaching. Thank you for making these videos. The illustrations help make things so much clearer.
0:40 ,dude really showed us 3 ev vehicles instead of internal combustion
I was looking for a VE explanation now that I have a standalone, no one gave an explanation as good as this. another amazing video, thanks a ton
You truly are the best teacher i have seen on you tube and that probably because you seem to understand what your talking about better than everyone i have watched . Keep teaching because your gifted
I can’t believe that I was intimidated by chemistry and physics in high school. This is beautiful.
Man I just want to tell you that you are doing a fantastic job! I've been seeing your channel since the beginning and is Soo satisfying seeing you grow to the post that you can easily explain such a powerful concept like VE! You're great, thank you for your great job! 👍🏻
Thank you for the kind words, I feel really motivated 😊
Thanks so much. You’ve got the best channel for explaining automotive engineering concepts.
Dude your videos are the best, probably most informative videos on tuning I have ever seen, thanks
This man just taught you how to tune your vehicle without TELLING you. Love it!
Absolutely fascinating. It's funny because I was literally mulling over this exact topic today. Love your videos, you're a massive reason why I've gotten into tuning/Motorsport engineering. You're awesome man. Keep doing your thing! 👍🔥🏎️
This is extremely informative, thank you for explaining this.
This is absolutely amazing content.
I can't thank you enough for uploading all this information in such an easily understandable manner on your channel!
That was gold. Thank you.
Again an awesome explantion, the last 10 years aftermarket ecu's and their base calibrations have come a long way. And installing in some cases only requires you to hook up 4-5 wires. my challange have been tuning the transient based on map and tps rate of change. Keep up the good work!
Very good video with lots of info and great explanation of mechanics behind ECU. You're making one of the most interesting content here, thanks dude. 👍
Your ability to explain this in a way that normal folk can understand is outstanding! Thank you 👍
The way you explain things is amazing. Please put out more videos.
Interesting animation at 02:08
I wonder what the crankshaft looks like 🙂
every piston has got its own crank 😂
This was a fantastic video. I feel like a lot of people would probably pay good money for this type of instruction - even though it was only 15 mins long. Most excellent!
I grokked most of this already, but you put it together beautifully, sir.
Passing it on to my son.
You make some of the best videos on youtube, thanks a lot! Learnt a lot that im going to apply when im starting my turbo miata! 🙏
Another fantastic video! Thanks so much! Every example and illustration was helpful, and the real-life demonstration was amazing! 😃
i haven't watched a minute of the video yet, but wanted to comment on how you showed 3 eletric vehicles as examples, love it.
This video is so good! Well done!
Great video as always, thank you!
I RARELY post on TH-cam. . . but have to say my hat is off to you on this video. By far one of the best videos I have seen for ECU tuning information. While it may be basic, it helps the average person understand what is happening and DEF gives a little peace of mind for those of us that are making changes on our own. Would HIGHLY recommend/request you go in deeper if possible. :-)
One of the best explained tuning video on the internet
Nice little troll at 0:42. I really injoy your technical videos, keep in information coming.
Hi from Brazil!
I really wish that you know that you make all the complex subjects a lot more easier to understand!!! Ty a lot for your job!!
Thank you so much. Never seen a video that just breaks it down to its simplest form. Keep up the good work brother and God bless you.
This is one of your best videos yet! By explaining VE maps (in D4A style) , I am much more confident in taking the plunge of tuning my NA Subaru. Thanks!
This Channel is one of the reasons i fell in love with internal combustion engines. They are a miracle of engineering and have centuries of development behind them.
Dude just taught me how to tune a car in 15 minutes. I love this guy
Great explanation, as usual
Has to be one of the most enjoyable informative car channels out there
Respect dude
Dude, thank you so much for this in depth clear explanation.
The BEST youtube channel ever. Thank you!!
I remember buying an EPROM with a different map for my 1983 Porsche 944. The performance gain that yielded was simply amazing but of course, all at the top of the rev range and at the expense of horrific consumption. It took another visit to the programmer to get it adjusted properly to the realities of my motor and driving prefs. I was utterly fascinated to see a summary of the engine’s parameters in graphic form, a format I deal with all the time in my electronic engineering work.
Never met these tables explained before.. Thanks a lot!
It seems you get right to the point even before the video even starts. I love this!
Great video explaining the basics of VE tuning and the practical example was really well thought out and added a lot
I'm new to this but could follow your video almost in its entirety and encouraged to delve deeper. Thank you for this outstanding video that is so well presented!
I will always be amazed by how easily you can explain all those things! Truly a scholar.
'it's 87 of nothing, it's not any paticular unit, it's percentage' lol. great vid, would love to see more on ignition maps, boost, fuel etc.
That was a great overview. Thanks!
Subscribed, this kind of video is exactly what ive been looking for.
Thank you so much for this video!