I had an BMW E90 335i with the DI N54B30 engine; had about 70K miles on it. One night I got bored and decided to pull the intake manifold off to see what my intake valves looked like after I had learned about the carbon deposit issue. OH. MY. GOD. The sheer amount of black carbon just caked and caked on every single one of them blew my mind. Luckily the problem was so well known on this car that there are valve blasting kits on the market that made the DIY job relatively easy. Still though, what a massive engineering oversight.
My 2020 2.5 Toyota Dynamic Force Engine has both port and direct fuel injection. I am totally amazed at my 2.5 Dynamic Force engine in my 2020 Camry LE (8,350 total miles) I recently took a 445 mile trip that put my car through just about all the scenarios a car could face including, freeway, hills, mountains, long gradual inclines, long gradual declines, 78 miles of winding uphill, downhill, sharp turns, not so sharp turns, manually downshifting, manually upshifting, and driving around a small coastal California town of Fort Bragg for two days. After I came back home I filled up the tank to check for the first time my gas milage turned out to be...an amazing "35.8 miles per gallon." I had to redo the numbers on my calculator to double check...445 miles divided by 12.4 gallons of gas. I am totally amazed! And all these miles were not "easy interstate miles"...only about 125, or so. My car performed better than I anticipated and this engine...totally amazed me! The car is rated for 39 MPG (freeway) on the window sticker. It looks like it would do even better! Totally amazing!
You got me curious, because I don't recognize it either. Mo is molybdenum. I don't blame you for not having that one memorized. It sounds more like a pop star's clothing line than an element.
It's used in high grade alloys and lubricants. Most people just call it moly. It's mined quite a bit in the north west, but South American mines and price crashes have slowed that down. It's a weird shiny purple
thanks! i can usually follow your explanations of these and other somewhat complex, complicated systems--outstanding work!!! as a result i feel (as an older person buying used vehicles vs new) i have a better chance of selecting something that may be a little more reliable and less demanding on the pocketbook. i never cease to be amazed at how you get to the meat of the issue without putting me to sleep!
thanks! looks that way--i got all of my car trading hopefully out the way last century--now it's all about reliability and decent gas mileage--but still, if i come across a car with fins on it, i might be tempted...
To get the carbon off, you gotta blast those valves with the walnuts bro...any nuts that fall down into the combustion chamber and get roasted, you simply collect in a "catch can" and serve those caramelized nuts at your next party.
Old Mercedes engines had direct injection. The intake ports would clog with a substance nearly as hard as diamonds. 4 hours to bead blast one head clean. It would slowly loose power over the years till it would barley run. No walnut shells were going to get rid of that crud.
@@EngineeringExplained What is your opinion of catch cans? And if you think they're beneficial, do you think they aren't standard equipment because they need to be emptied periodically (or for some other reason)?
I have a PI + DI motor and love it, good horsepower with great economy and no carbon build up, you can't ask for more really. Toyota Mark-x 350S. 2GR-FSE motor, 314hp.
Dual fuel injection, the best of both worlds. I had a feeling this system will become more common in the long run. The newer Ford Mustang GTs also has dual fuel injection, which is awesome, and once this system gets more improvements, I bet most of the automakers will convert to dual fuel injection. I wouldn't be surprised if I see more Toyotas, Fords, Chevys, Volkswagens, even Mazdas adopt this setup in the future
D4-S training talks for my job specifically mentioned carbon buildup. D4-S has an injector cleaner cycle that shoots a high-pressure air-fuel mixture laterally across the notch in the injector tips to clean them. It happens during idle every approximately 17k miles.
I just wanted to drop a comment to let you know how much I enjoy your channel. I have a decent grasp of the basics of how various aspects of cars work, but I always learn something new. I enjoy your approach to the various topics, and you have a great balance between keeping it very approachable and easy to understand but also explaining the science and engineering behind how something is designed. Keep up the awesome work!
Obviously depending on the application, it seems as though you get the best of both worlds with Port + Direct Injection, thank you for the explanation on all of the variants. It trips me out that all of these ways to inject fuel were all from the minds of engineers. It's pretty rad if you ask me.
Hey Jason! Thank you for the great content that you post all the time. I would be very interest in getting your take on the auto Start/Stop engine function found in most modern cars today. Is it good, or is it actually bad? Your input would be highly appreciated!
Great explanation. I wish I knew how my Coyote chooses to utilize both its port and direct fuel injectors, and at what RPM ranges. Thanks for your excellence once again on the whiteboard!
@@_aullik No for real, only people from some nations think it's hard to memorise. Some languages have things like PDK: Porschesdoppelkupplungsgetriebe.
Thanks again for all that you do buddy! Just used you video to help educate a customer on the importance of fuel injection services on their new Subaru.
Very awesome video! This made me super happy to hear when Toyota was pushing the D4S dual injection system because it is so efficient. You get the best of both worlds without being stuck with the compromises of DI.
Super awesome explanation 👌. One small observation which kept disturbing me in your sketch on the board is *When the piston reaches TDC, the connected rod is straight, not tilted. Once again great job. Love from India.
DI engines will build up much more carbon than PI engines, and Fuel Additives cant remove carbon on intake valves. And DI engines are very sensitive to temperature. In high temperature environments, more fuel needs to be injected to reduce the temperature of the cylinder. However, the cooling effect of the injecting fuel is not good, engine limits the power output in case of overheating.
The only way to clear the carbon deposits on the intake valve is to disassemble the intake system. DI engine need clear carbon deposits every 40k~60k miles.
Got a real laugh out of the Moe for Molybdenum, I have a feeling you're pulling our collective leg there. As a mechanic my eye went immediately to the right side of your white board. I was bouncing out of my chair until you mentioned valve deposits, the bugaboo of DI! Ask anyone who has had to have their BMW's DI intake valves blast cleaned how big (expensive) a problem DI resultant intake valve deposits can be.Always enjoy your videos. If you weren't kidding about "Moe", well chem wasn't my strong suit either.
This video was very well done for someone like myself fascinated and curious about the internal functionings of the combustion engine but not a full on gear head by any stretch of the imagination. I gotta subscribe so that I can learn more! 😉
Stratified charge: what's old is new again. I remember when the Honda CVCC engines made their appearance here in the States in the early 1970s along with Honda's television commercials touting its benefits. As for blow-by, with the electronification of today's cars, catch cans with a solenoid valve to the sump can solve the valve deposit issue for the most part, EGR excepted. This seems inevitable to me as engine makers reach higher for fruit. No more low-hanging stuff to tweak.
If you look underneath the valve cover of many direct injected engines today, they already have an extensive oil separation system for the PCV, plus a direct pathway to the engine sump for oil drainoff (no valves required if the tube goes straight down below the oil level). One example of this is the Ford 2.7T, and another is the Honda Civic Type-R engine. Catch cans aren't really a great solution, because for the most part they either aren't catching enough oil particles (today, proper PCV oil separation systems are capturing sub 1 micron particles), or they are too restrictive. And in the winter, they freeze (which is really bad for your car as crankcase gases go out the fresh air tube... and when that freezes... blows your seals). All of those catchcan ads you see on forums are only telling part of the story when they say "LOOK HOW MUCH WE CAUGHT!!!11!" when they show off the fluid, because the fluid is a mix of water, gas, and oil. Gas and water you don't typically care about because they burn off when you drive, but the oil is what causes the deposits (the proper way is for those catchcan companies to actually heat the fluid so that only oil is left).
And don't forget throttle body injection! That one was probably the most revolutionary of all... And there were electronically controlled carburetors, with oxygen sensors. And my favorite, mechanical fuel injection. ;)
GReat video as usual. Thanks for the time & effort to produce these highly illustrated and intelligently explained complex technical systems. Easy for all to understand.
Your videos are really very very good, I have learnt a lot from them. Thanks for making them and keep it up. Engineering Explained is my favourite channel on the RU-vid.
You are a really knowledgeable person. You really should be a professor of the best automobile engineering university. Although I'm a student of commerce and I don't know how well the professors teach in those universities, I feel like I wouldn't have needed a better teacher if you were the one teaching.
VW 2.0TSI engine owner knows the carbon build up problem. At +/-50 000miles theres a 2mm. crust behind the valves causing cold start missfire. Hope VW will change to PI and DI combo soon :)
You can just buy a oil catchcan and reduce the problem. And if VW's TFSIs actually met Toyota's specification about valve clearance from the 1980, then you would have less oil on your valves too. By the way, if you don't drive your car for a while (like weeks to a month) then the carbon deposit can dry out and flake of, these flakes CAN get in your engine when starting it again. p.s. I said "can", not "will". But engine builders say that if you leave an engine disassembled for a week or 2, the carbon fall off as soon as you pick up the valves standing on your desk.
This video makes me wonder if Atkinson cycle DI engines might avoid carbon buildup issues because they force gasoline into their intake runners, where the gas can clean the valves. Perhaps this could be a video in the future?
DI engines with walnut blasting may make the valve look good. However, if that blast does not touch valve seat, carbon build up will cause burnt valve.
Actually Toyota’s reliability comes from their engineers and their Kaizen philosophy in their whole design and auto assembly process. Everyone had port injection by the 90’s, and not every auto maker made reliable vehicles like Toyota.
There is a german Engineer with a Company called RSklinik who also works at Volkswagen and offers intake valve and manifold cleaning. And he clearly names the Problem with the Carbon deposits caused by Not using Port injection. An example always refered to is the RS4 B7 which loses approximately 40hp in 40.000 km just by Carbon deposits (depends on oil and driver).
Good info! I never knew why they did both, thanks! The only car I see at the dealer I work at that uses both is the NSX. I always thought it was just because they needed more fuel for all that boost, but now better understand the engineering purpose behind it. Love the whiteboard videos dude!
Thank you for this informative video about DI and PI engines. Could you also do a video on how to reduce or clean carbon deposits on DI engines? Much appreciated!
@@EngineeringExplained Is there any other brand than Toyota and they D4-S who are using double injections direct and port ? Never heard anybody else doing that, since Toyota introduced Its D4-S.
@@MrNangu Ok good to know! But compare to Toyota It's only 1 engine in VW. While Toyota already many engines. So I would go for a Toyota rather than a VW which isn't reliable at all!
Good job on this vid. I never nod off watching your stuff. My solution for my new 3.6 V6 was a catch can and you should see all the crap it catches, none of which should be ingested by any engine port injected or not🤮
Manually cleaned the intake ports/valves my 2010 gti twice... I wish VAG brought the euro motors over to the US because those came with 2 sets of injectors (like in the new rs3)... Whether or not the car has a dual injection system will influence my next vehicle purchase.
lexus already knew about carbon build up of DI only design, that why when they released their flagship sedan 13 years ago, both DI and PI is used on their LS460. As the LS460 needs to be their most reliable model.
Your videos are amazingly informative the thing is you can have the best engine if your fuel injection system does not get the fuel or the spark for the compression it doesn't matter how good the engine is this is the problem with vehicles
Thanks for tackling this, Jason. I have been curious about some of the specific techniques used in the D4-S system on my FA20 and found there is little info out there. Wherever you got this info thanks.
Another unmentioned benefit is the injector sizing is able to be better optimized to increase accuracy and control, since to required flow capability fo each injector is not as high as a conventional DI or port system which can help improve emissions, particularly to help meet new particulate standards.
I have two questions: -for a PI+DI do you need two differentes fuel system of differents pressures ? -does that work with diesel engine cause diesel only uses DI right ?
single source, the DI injectors are driven by a secondary high pressure pump that is mechanically driven off the cam. In DI only it's the same way actually, 2 pumps.
As they said one system, two pumps. But if you have a diesel engine you can get many of the same benefits with even more efficiency by using a propane injection system that puts propane in the intake system and causes a more homogeneous charge of fuel to be burned by the diesel fuel when it is injected. Then the diesel fuel becomes like the sparkplugs controlling the timing of the combustion.
@@davidscott5903 You're right, except methane is actually better for diesels. A diesel engine can work on 45% propane/butane and 55% diesel, OR it can work on 10% diesel and 90% methane. A diesel engine that runs partially on methane will have increased power output and decreased emissions because of the homogenous a/f mix. The only drawback is that you need another tank to be placed in your car/truck and you need the system to be setup and tuned in. That's not to big of a deal when you factor in propane, butane and methane are all a lot cheaper than diesel.
@@sasjadevries The only reason that I mention using propane is because of the availability of propane in the USA, and the fact that it is in liquid form in its tank. I didn't know about the amount of difference in ratios. Do you know the reason for the difference? I would like to know if you can find out. Thank you.
At about 5:15 you mention that you start injecting fuel (port injection) during the exhaust stoke when the exhaust valve is open and the intake valve is closed. Would this not just have the effect of spraying fuel on the back of a closed valve?
Great explanation on the topic! I presently own a 2014 Mazda 6 GT model with the 2.5 l with 120,000 Km. The car has been very reliable, don't even want to look at those valves. You mentioned Toyota has both port and direct injection. What other companies have engines with both PI and DI, besides Ford. Thank you!
Hello, First of all thanks for sharing video. I do have few query, appreciate your reply 1. Does this video is apt for gasoline only or for CNG also. 2. In PI, during injection of fuel it will displace incoming air thus affecting volumetric efficiency, considering Atkinson cycle.and thus less power will be produced.
manish mishra Yes, in CNG there is a displacement of air in PFI, but the required pressure for DI is quite high which usually needs a high pressure fuel pump. Usually this is done only with LNG. Westport Power does a dual fuel (diesel plus DI LNG) which has one of the lowest CO2 for a combustion engine. Generally for SI engines, though, turbocharging is cheaper than DI for CNG and that is what most engine manufacturers do for CNG, though some don’t turbocharge but instead raise the compression ratio to roughly 12:1 and the efficiency improvement can offset the air charge loss from fuel displacement. The air displacement for petrol PFI is lower than the air density improvement from cooling, but this is not the case with CNG which has roughly 10% air volume reduction.
It’s seems like you are in my classes, a year and half ago we spoke about Volkswagen faking there emissions then I see you do a video. And now yesterday we spoke about port and direct injection and those carbon deposits on the valves with DI.
Toyota actually had dual injection since 2006. My 2008 GS 460 has it. It uses a mechanical fuel pump on each head, run by the cams, to get high enough pressure for direct injection. It has a two computers on top; one for every four injectors.
The legal department likely advises engineers to not mention the fact that the engines they are developing have inherent flaws in them and as a result could open them up to legal problems and possible settlements.
It seems that the video progress bar hits the vertical lines of the board almost exactly when/where the subject changes to what's in its area. Was it on purpose? That was very nice!
As a mechanic, I've noticed my wife's Mazda2 Skyactiv engine doing its retarded timing catalyst warm-up cycle too. The car sounds cool, it's got a gruff, slightly raised idle speed like a poor man's world rally car! It is linked to the wheel speed sensors, so if we roll it back down the driveway during warm-up it cuts out & returns to a normal quiet idle before you drive off.
Dangermouse Usually these days they will use a software model of the catalyst temperature to switch the catalyst light off mode, at least that’s what my software does. On cars with this algorithm if you drive off that mode kicks out earlier than if you just let it idle.
So from what I understand is port injection is the way to go. Deposits are reduced by a landslide but still possible from the image shown in the video. My question is will an engine still benefit from an oil catch can or oil separator even if it’s port injected or is it overkill and not necessary? Thanks in advance!
I am in the market for a new SUV. Contenders are (all 2019) Rav4, Santa Fe, CX-5....with a heavy nod to the Rav4. (Toyota dealership in my town, none for Hyundai and Mazda)...as I keep researching, the Rav4 keeps coming out on top. (even before the bonus of a dealership in my town) The dual injection issue addressed in this video locks the Rav4 as the winner. (Rav4 has the D-4S engine) I keep my cars a LONG time, and I don't want to have to deal with carbon buildup. Plus, the added bonus of Toyota quality. Only downside to Rav4..no android auto. But I'm the son of a GM engineer and my 15 year old Trailblazer is running well. I might as well keep it a few more years.
Jason how did you get so smart? What classes did you take to help you get to know so much about engines and stuff? You're pretty young yet you talk like a older professor that knows so much!
Thanks for the video :) really explained a lot. Wonder if the whole DI issue is the same for diesel engines? I've never experienced modern Diesel's torque (been meaning to for years 🙁) but we have an old Peugeot 405 indirect injection turbo diesel which has decent torque compared to most modern cars here; the 1.5 liter petrol engines in Toyota Allions, Premios, and 1 litre Indian cars; and has lasted 25 years without any major engine repair... I wonder if modern diesels would last like them
Hello! Big fan of your videos. One thing got me curious, for more power isn't it better to use port injection at high rpm? My thought is that direct injection is limited by it's opening time. As far as I know Vw 1.6 fsi engine is ok at low rpm and it's quite torky, but at high rpm is not brilliant... a port injection engine may be not so efficient but for power it's more useful (ex: Lamborghini Aventador v12 6.0 mpi)
you forgot some other disadvantages of direct injection that OEM will never tell you mainly the emissions. NOx can not be regulated through a three way catalyst in lean combustions, DI produces sut just like diesel, they require a particulate filter. thank you for the great video, it would be nice if you mention your sources at the end of each video :)
sure, let me explain why many care. imagine having no exhaust after treatment on all cars and then imagine someone carrying a child and walking behind a car with engine on. I would rather assume that nobody enjoys the wonderful smell of sut flowing into their lungs. PS: Sut is not only cancerous, it can cause sudden heart attacks and vein clogs. Another point concerning EGR, it keeps ur combustion temperature low. Apart of avoiding Nox, it improves the durability of the engine so yiu might need it.
Engineering Explained, and Savagegeese reviews, are the only ones I have seen address the problems with Direct Injection and carbon build up. Some vehicles have severe build up as early as 20,000 miles, they then have to spend about $1,000 to fix it, until the next time. Hopefully Dual Injection will become standard in the future. Until then, some Toyota's and Ford's F-150's have Dual Injection, or a few still have Multi-Port, like Chrysler/Ram.
In the future? It already is a standard. Only some very low end models are still MPI only. The worst carbon deposit problems I've seen so far on the internet seem to be on turbo engines
That's because carbon build-up can vary from engine to engine- and yes, that means not every DI engine has valve deposits. Most newer engines are utilizing a sub 1 micron PCV oil separation system, which in most cases is sufficient to keep intake valve deposits away on DI engines. There are a couple of systems out there, you can youtube search "Dana Multitwister" for one type.
He forgot to mention Mazda engines run the intake valves at 700 degrees to burn off carbon deposits on intake valves. And he didn't mention oil catch cans can capture the blow by. Maybe someone can make an EGR filter now too. I love how electric cars don't have any of these problems though. I'm just waiting til an electric car has a 600 mile range!
@@tails300 good question. I'd like to know as well. I know Ford and Toyota have engines with both port and direct injection. Not sure if any other manufacturers are doing that.
I love your videos Jason, really good explanation that even non engineers can understand, I like watching your videos more because I am currently studying Mechanical Engineering, I'd rather watch these lectures than boring, Calculus or Chemistry lectures, non the less, I really get hooked into the videos, pretty interesting to see how our modern cars work to get by all the Emissions Standards. I also own a car with a Toyota D4-S (Subaru) Boxer Engine, so it's really nice to know how it operates also during cold starts.
@@brandoncastles2900 Engineering is a broad field. Specifically this is Mechanical Engineering, and it’s not all about cars, there are many divisions into this Engineering. It’s an interesting field if you like the design and analysis of any component that moves, including fluids.
jack GB the valve lifters can get noisy sometimes making a ticking or tapping noise when in park or idling at a red light but its really only once in a great while it does it. The gx460 though with the 1ur-fe is notorious for it (like the guy above me says)
