Rotary Valve Show and Tell - BMW E36
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- เผยแพร่เมื่อ 10 ก.ย. 2024
- Describing how the axial flow rotary valve cylinder head works in our 1999 BMW 328iS. Engine runs at 17:35. Hopefully will get on the dyno soon!
If you would like to know more about this head or the car, please leave a comment down below.
Here is a link with pictures and dyno plots.
grassrootsmoto...
Specs: 2.8 liter, Inline 6. Maximum RPM run so far is 7,000. Upgraded from 24 to 30lb Fuel Injectors.
Compared to a normal cam, the valve timing is approximately 250-260 degrees of duration at 0.050" of lift. Intake-Exhaust valve overlap is about 40 crank degrees. Stock bottom end and block. The engine could rev much higher with upgraded bottom end components and the appropriate harmonic balancer (supposedly hits resonance at 7280 rpm) since the valve train has no reciprocating components.
This is the first modern production car that we are aware of that has been modified with a functional axial flow rotary valve engine. We have also not seen any other BMW's or inline 6 engines with this design. The ultimate goal of the project from a power perspective was to exceed the hp/L level of a Euro E36 engine, which means we need to achieve about 240 RWHP versus the 167 RWHP we measured before the original head came off the car.
to make it better, you can make two large valves with ports to each cylinder and run it lengthwise along the engine, one for intake, one for exhaust and then drive it with the engine timing chain. This helps because the intake and exhaust are separate and the exhaust won't be heating the intake air, no noise from a mile long chain and no special 90 degree gearbox.
I didn't expect this to be real when I clicked on it but this is super impressive. You can clearly see the potential already. Super nice job guys
Thank you!
Good work! Imagine selling the car to some unsuspecting used car dealer, without saying anything. Maximum confusion!
It's fairly noticeable from an exhaust note standpoint :)
I like your idea of the floating cylinder seal being made from pistons- certainly being resourceful
They were actually custom made on my mini cnc mill. They took about 20 setups each. It was a lot of work
MrPizzaman09 That makes sense
Incredible work. Rotary valves are a fascinating concept.
The rotary valve technology is superior to old valve system
But the problem is the hight temperature that damage the rotary valve within few days at best
I hope that AI can solve this
@@unknown-unknown69 AI is not necessary. This is a problem that has been solved by the aerospace industry. It is cost and a lack of motivation that remains the problem. If it was truly wanted it could be solved.
@@challacustica9049 can you point me to the aerospace industry solution?
@@avisuflight there are a number of metals known as "super alloys" used in the aerospace industry that can take extreme temperatures. The most common of these is probably inconel.
In addition to the metals themselves, the aerospace industry has long been making use of skin cooling, in which a film of cooler air is ducted through the material with very small channels and serves as a barrier from the hotter air.
Neither of these are economical solutions to implement today, but they certainly exist. The latter solution is more feasible to implement here with the rapidly increasing capabilities of metal additive manufacturing
You guys did an amazing job, very bold to take your ideas from a B&S single to a modern automotive engine, and it worked! This video was a great demonstration of the scope of the project and thanks for taking the time to put it together.
You guys are nuts... Absolutely insane in fact,but in a good way! Keep up the good work, and keep thinking outside the box. Do you fellers even have a box to think in? Seeing this run on the stock ECU is just crazy. And it doesn't even throw a fault code! You two are truly awe inspiring... I hope to see more of your insanity. :-)
Inside the box, outside the box, peeking into other boxes and taking from them all, it's all fair game when trying new things.
I too am very impressed that the stock ECU is so tolerant, but if you look at what we are doing, there isn't anything super crazy about it. It's still a 4 stroke engine and we are using all of the stock sensors and emissions equipment. The ECUs in these old e36s are super tunable.
Thanks for the compliments, if folks think we are nuts, we must be having fun and doing something right!
Thank you for sharing in depth. It has been wonderful following along and seeing everything come together. It runs really nice, looking forward to seeing some dyno plots of the results especially compared to stock. I would love to see more driving videos too. Great job guys! Love it
My Masters degree thesis was on rotary valves, love your work
Thanks! Have you seen one in person or tried to build one?
That gold piece that is the top of the cylinder and the bottom of the tube valve surface could be made of ceramic with much tighter tolerances and could be made as one piece instead of two halves. The cover over the tube valve could also be ceramic. No expansion or cooling issues. Put a bevel gear on each valve and use one longitudinal shaft to drive all the tube valves. The tube valve could also be made of ceramic with much less valve to housing clearance which would mean less leakage. Position a slotted window opposite the intake port at a slight angle so that the injectors spray right down through the intake port when it aligned with the cylinder. Position the injector port back from the intake port so that the injector port is covered the rest of the stroke. I designed this exact layout about 20 years ago. Nice job on your R & D.
Thanks. It's hard to actually make this all work the first go-around and with the machining and financial resources at your disposal. Making the floating seal one piece is doable, but it reduces your ability to make the valve fit the floating seal exactly.... I made up my own honing process to make the half-pipe shape exactly the right size. Also, any thermal expansion in the wrong direction won't end up with a seized valve. So far, that hasn't happened on any of the 5 rotary valve engine's I've made.
The port injection for the fuel injector is an interesting idea. Certainly more difficult to implement and deal with the high temperatures and spacing constraints in this design.
but ceramic is very weak on stress, it would broke after a while due to multiple ignition in the chamber...but I notice that the valve seem to be overweight, maybe something thinner in titanium would do and also the size seem to leed the engine top end to something like 8k rpm... maybe onlock the rev limit nor reduce diameter. the length seem to be short enough to bring rpm to 8k at least...it have the runner after the valve but may some tuning is require this way!
you guys are just awesome
Bro had 3 hands for a second
Excellent vid!! Good explanation and show n tell lof the rotary valve head you guys came up with! Sounds like a cammed up big block chevy at startup...
amazing job. you guys are awesome
Shared with my father and a friend, thabk you friend 😊
With that much airflow capacity, I think you would need to rev it much higher than 6-7k to get any improvement. If you manage it, I bet it will make over 270-280 crank hp.
We would love to rev it beyond 7k, unfortunately the BMW M52 engine has a known resonance on the crankshaft at 7200 rpm. If you linger there too long the crankshaft will fatigue and shear.
That's really cool. Keep it up!
Well done, a bit of smoke out of the rotary valve but work well with 100 ,% for goof efforts
This is so cool
It’s solid!! I like this ..why have car manufacturers not followed this ?
that's some serious work mates
Wow. This is some serious backyard engineering. It must be extremely difficult making it reliable.
This design would overtake traditional poppet valves at very high rpm. Stock m52 manages around 100%VE 4.5krpm.
Where can i start learning what you have learnt? 😮 Im Absolutely amazed
Please sone direction where to start reading? Im knowledgeable on internal combustion engines and valvetrain systems and understand engine timing fine.
But these valves of yours are a new thing to me, wow!
Just did some quick math for you using David Vizard's cam theory based off of a few statements you made plus the engine specs. You said you have 50% more valve area than a poppet valve setup, right? So the equivalent of adding a 3rd equally sized intake valve. In that case, after running the formula and area conversions and whatnot, you should start with a 116-degree LSA and 116-degree intake centerline.
If you increase compression, the LSA will change 1 degree wider per point of compression added, or 1 degree narrower per point of compression reduced (10:1-10.5:1 is always considered "baseline compression" so 116 is for your baseline since you're already at 10:1). The centerline doesn't change as that's entirely dependent on the displacement to valve area ratio and unaffected by other factors such as compression, and in the case of pushrod motors, the rocker ratio.
For duration and overlap, as I stated in a previous comment on the other video; total duration and overlap are more critical than .050, especially since the rotary valve design is very different and not really reliant on any .050 measurement. Additionally, engines with much higher flow potential of the valves need less overlap to get the same results, specifically at high RPM, as engines with worse flowing heads and valvetrains.
With that in mind, if your 40-degrees of overlap is to be assumed correct as the "total" overlap and not .050 overlap with your reported 110LSA, if you want to keep that much, you'll need to increase to a 272 duration on both valve ports at the new 116-degree LSA. On the other hand, if it isn't, you can get your equivalent overlap by finding your current total overlap using the formula "total duration-(lsa*2)" and then converting to the new LSA by reversing the process "116*2+total desired/advertised overlap = new required total duration"
My recommendation is 40-60 degrees of total overlap on the new LSA, and probably no more than 75-degrees if you want it to be any kind of streetable. Lastly, all of this cam theory stuff can be verified by the latest video on the Cattledog Garage youtube channel, as well as all the videos, books, and general teachings of David Vizard. If you go to them and are confused by the 120 formula being for CID/8 (8 being cylinders of a V8) I have all the necessary conversion formulas for metric valve sizes and converting 2 intake valves to single intake valve diameter, all you gotta do is ask.
Great engine, but what about those 3 arms and 2 vocal registers!?
50 years ago, the Britts found that the sharp, square edges were a determent, causing choppy operation. You might try tear-dropping the edges (funneling) to create a more gradual opening/closing event.
It's not a perfectly flat edge, there are some radii in the corners giving it a little bit of ramp up and down. The tear drop is a cool idea, however in practice it would be very difficult to fit. On the rare occasion that it has run on all 6 cylinders, it purrs like the in-line 6 it is. We have some significant updates coming to the project soon, I've spent most of the year rebuilding it and modifying the ports for far less overlap and more conservative timing.
Maybe it's my phone but that engine sounds like it is about to rattle itself apart. It sounds terrible. Also, why yould a rotary valve engine need with a camshaft? The valves are opening and closing using a chain and sprockets.
Heck of a job!! man you guys have gotten rid of a lot of glitches! Have you got it on the dyno yet??
How much energy you gain after eliminate the valve springs?
Hello I'm a college ME major and I'm conducting a project regarding using a custom made head on a production engine. First question, I'm trying to rotate my cams however the cogs on the cams are too far out from the face of my crankshaft timing gear to take advantage of the gear. I was thinking of using a worm gear system to rotate the cams, a system used in the Ford GAA armoured tank motor.
Would you recommend staying with a chain system, or would gears be more preferable???
Dyno numbers? I love this. Had been thinking about the same project for one of my old straight sixes. Share the floating seal/valve set-up?
Hi guys! This is very good job! I always ask myself about this system and turns it in my head to make it possible... but first time I see it in action! would be interesting to put it on dyno to compare power curb... next step would be to use a variable length and a high rev engine like klze v6 engine that could be able to reach 14k rpm... What is the compression ratio? I read that it could be much higher than regular cam engine, maybe up to 15:1 and I guest that it could be even higher with the addition of other technology (3% hp gain for each compression ratio point gained). Also I m not sure about what you use to seal the tube on the head ? The first thing I heard about it was some rings (circular and linear) but you are not using any...
Thank you! The compression ratio is about 10:1. It's still completely stock in the block and rotating assembly. We have yet to take any of the lower end apart. The stock redline is 6500, but we've been going to 7k. If it shows potential, we will rev it faster on the dyno if needed. There is supposedly a harmonic vibration that likes to break the crankshaft at 7280 rpm. The rest of it could be spun very fast, probably 10k without any major problems.
There are half pipe floating seals, which are shown in this video. The ends of the rotating tubes are sealed with spring loaded rotary shaft seals.
@@MrPizzaman09 thanks! Keep us informed of any further test! That’s really interesting and would like to see the power curb compared to the stock one! That could tell a lot to see where the real gain is and if the size is good!
Good job!
@@patricklafontaine4313 we did some volumetric efficiency measurements and it beats a M3 at certain rpms, so the potential is there
Also, how do you keep the chain lubed
We don't at the moment, but you could use some motorcycle chain lube.
Has AVE given his opinion?
Power and fuel improvement?
Very interesting project and thanks for some good content. Have you guys fixed the cooling system issues since this video was uploaded? Or the dithering ot the valves that is causing the blow by to begin with? That last hurdle, although a big one would make this a fun daily driver lol
Bro built this whole thing and still has no problem with a cold rev to redline...how
If it’s ok to ask, what kind of materials are you using? I’m working on a similar project currently and this is very helpful.
We used high lead bronze on the floating seals and 4140 or 4340 for the valves. They had a chemical treatment on the running surface, but it quickly wore through. Warping due to heat treatment is going to be challenging.
I highly recommend making your contact surface from the floating seal to the valve as large as you can. The higher the contact pressure, the more difficult it will be to seal and make it last. The other key thing we did is to lap the floating seals to size since the seal warps significantly after cutting all of the material out. Let me know if you have any other questions.
@@MrPizzaman09 thank you! Most of my machine work is done, now waiting on some time to re-adjust the exhaust closing event. I failed to build any compression as it simply hung the exhaust valve open for too long. Thank you!
@@samstewart6495 we had similar issues as we did 260/260 duration with about 40 degrees of valve overlap. It was way too aggressive, so we could either get okay filling or an okay power stroke, but not both at the same time
@@MrPizzaman09 this is about where I am currently. Glad to hear someone else has struggled with this. Right now the engine hardly builds compression. I think the overlap is going to be the main issue, it will probably need more overlap than I can provide due to the way my engine seals. Is there any way I can contact you elsewhere?
@@samstewart6495 taylorp035@gmail.com
well you never have to worry about bent valves, if either timing chain breaks.
Shouldn't those be called Cam Tubes or cylindrical valves, instead of camshafts? there are no shafts in your setup.
We used to have a timing belt drive the valves and it broke at full speed 6 times. Nothing goes wrong since it's not an interference engine.
They are axial flow rotary valves. The concept and name has been around since the 1940's but they haven't been very popular due to the engineering challenges behind sealing it.
Does it feel faster or get better milage?
It pulls pretty good when it's tuned right.. The dyno should tell us for sure. MPG's is unknown until we can get more miles on it.
@@MrPizzaman09 3 years gone by.........????????
@@timothylanders3189 We took it to the dyno. The mass air flow sensor was a Chinese knockoff and caused the engine to think it was loosing air after 4500 rpm, so it would fall on it's face. There is a dyno video of it out there if you search.
I don't think we will know the mileage, though one day we drove it for ten miles straight without stopping and the dash readout seemed reasonable. I'm not sure if that was vacuum based or calculated, so who knows if it was accurate.
Since then we have reduced the duration of the "valve timing". We had a few mechanical failures, but sometime this summer I hope we get it tuned well. It idles much better now. We also put larger diameter spark plugs that are a normal size so we could get hotter ones that don't foul from the oil so quickly.
do you think that the rotary valves would hold up well to a couple psi of boost?
The valves and lower floating seals, yes. The intake rotary shafts seals are probably good for a few psi. The top seals may spray oil everywhere and may need stiffer springs ontop of you go too high. Fairly easy to modify.
Hello.
Nice, explanatory and useful video. Thanks.
Three questions:
1. Have you measured the bending of the rotary valve under full pressure? I mean, you support the rotary valve on its two roller bearings (at some 150mm(?) distance from each other) and apply a force of, say, 3 tons / 6,600lb (the peak combustion force) at the middle (or, say, through the bronze seal). This bending is crucial for the sealing quality and the leakage.
2. Isn’t the lubrication between the rotary valve and the bronze seal, a total loss? Have you any idea (approximately, I mean) of the lube consumption?
3. In the 21:32 of the video, I see no vacuum in the intake manifold for 300rpm idling. If this is correct, what is the idling “fuel consumption”? Supposing you cannot idle at leaner than 20:1 air-fuel ratio, then at idling they pass some 7liters (2.8lt * (300/2)fillings/minute * 1minute/60sec ) of air per second through the engine, or 32Kg or air per hour. With 20:1 air-fuel ratio, this means 2.2lit per hour idling consumption, which is too high (at 330rpm idling, the VVA-roller Honda Civic 1600cc B16A2 engine was consuming 0.35lit per hour; see at www.pattakon.com/pattakonIdleValve.htm )
Thanks
Manolis Pattakos
1. I have not measured the bending, but I did do some FEA. After tearing the head apart last winter, the wear on the seal looked really good and it didn't seem to show any issues with wear on the sides. I wouldn't be surprised if the seal wears in the some more after it sees some extended run time under load. Also, the OD of the valve is about 52mm with 4-5mm thick walls at a minimum... this is fairly stiff.2. Yes, the oil is a total loss at the moment. You could collect it and feed it back into the crankcase if you wanted to, but that's not a concern of mine at the moment. I have a lot of adjustment for the oil consumption rate, but since I want to be on the safe side, I choose to keep it well lubricated. Probably anywhere between 10-100 miles/quart if you were to actually drive the car. The Ralph Watson car did even better than this. It costs a lot of money and time to make and replace a valve and seal, so I don't want to find out the hard way.3. At idle, only about 1/3 of the air makes it into the cylinder due to the valve timing (~50 psi of compression versus 165psi), so you can divide you numbers by about 3. I had a 5.0L V8 in an BMW E39 M5 that used 1.3L/h of fuel at idle and that engine was definitely not optimized for fuel consumption. The E36 BMW was designed back in the late 1980's/early 90's, so the Honda engine probably has a bit more development behind it for fuel economy as well.
Thanks for your prompt reply.
If my questions are bothering, just ignore them and I will delete this message.
If not:
1. Even without the two long and asymmetrical openings (the intake port and the exhaust port) at its middle, a long pipe having 52mm external diameter and 4-5mm wall thickness cannot help being flexible. Supported near its ends and loaded by a few tons at its middle, doesn’t it flexes (at its center) for a couple of tenths of a millimeter (say, a hundredth of an inch)? When the rotary valve bends leaving a gap of, say, 1/200 of an inch, the leaking burning gas will melt the bronze as in a leaking poppet valve. And what when the one side of the rotary valve will run red-hot increasing the overall flexibility? The smallest flexibility can cause severe problems, especially at the exhaust side. A reasonable improvement would be to increase the wall thickness of the rotary valve and to bring the two roller bearings, wherein it is rotatably mounted, as close as possible.
2. The 10-100 miles/quart of lube oil consumption is too much. For the same distance the car consumes about a gallon of fuel giving a fuel to oil ratio 4:1. The 2-strokes were / are working on a fuel to oil ratio well above 50:1. Most of the lube oil around the rotary valve, between the rotary valve and the bronze seal, cannot help being suctioned into the cylinder (during the suction cycle, just like the oil from the intake poppet valve damaged seals) wherein it will be burnt. Ralf Watson prototype car was consuming several times less oil. I think the 10-100 miles/quart of lube oil is a mistake (please re-check the numbers).
3. I can’t see how, with wide open throttle, you can prevent air-fuel mixture and/or exhaust gas from filling the cylinder. 50psi peak compression pressure is too low, no matter how aggressive the timing of the rotary valve is. Even if the intake port closes at 90 degrees after the BDC, the quantity of gas trapped in the cylinder is more than 60% of the cylinder capacity.
Thanks
Manolis
1. It works well as designed so far. I've had the engine really, really hot and it doesn't appear to have any sealing issues. I did run into this problem with the smaller Briggs and Stratton engines with the same design. The BMW has much, much larger diameter valves versus the length, so it doesn't seem to have a problem. The spanned distance is only 6 inches wide. If I remember correctly, the FEA said a deflection of less than 0.001". Thermal expansion is a much bigger issue. 2. Oil consumption really wasn't a concern of mine for the project. When I first ran the engine, it was more like 1 liter per minute (hence the huge amount of smoke in my earlier videos). Oil is really cheap compared to the rest of the project, so I haven't spent much time trying to improve it after we added the oil pressure regulator and two levels of needle valves.3. The amount of air could vary depending on the valve timing and idle speed. The air fuel ratio could be higher than 20:1 as well, but probably not much higher than 25:1. Idle fuel consumption isn't very high on my list of priorities either. I've burned through about 40-50 gallons of fuel so far on this cylinder head. You can see my video with the fuel injectors spraying into the valves without the intake manifold and see how much they are spraying in.... it's probably 50x higher once you press on the pedal.The other thing to consider is that my valve timing compared to a normal cam is about 250-260 degrees of duration at 0.050". This is about what is used for a muscle/drag car and is almost not driveable on the streets. My BMW drives halfway decently, but if I were to make new valves, I would reduce the open time by another 10 degrees.
Thanks for your response, wherein I read:
“Oil consumption really wasn't a concern of mine for the project.”
and:
“Idle fuel consumption isn't very high on my list of priorities either.”
OK.
But let me wonder:
What is the point of your project?
If it is to make “lots of power”, you should start with a high revving engine (say, a sport car or motorcycle engine whose power is limited by its valve train flow capacity and/or by its valve train red line).
If it is to show that the Cross Rotary valve works, it does. Roland Cross had a version with floating cylinder (imagine your bronze seal secured on the cylinder liner (no need for extra rings or for high pressure O-rings)).
If it is to make a normal engine for cars / motorcycles, the oil consumption and the fuel consumption (and the emissions) are crucial issues / first priorities.
I also read:
“You can see my video with the fuel injectors spraying into the valves without the intake manifold and see how much they are spraying in.... it's probably 50x higher once you press on the pedal.”
It can’t be “50x”, not even “10x”.
The quantity of fuel injected per cycle is, more or less, proportional to the quantity of air trapped into the cylinder (the lambda can’t vary too much). And this quantity of trapped air does not vary that much (as your “~50 psi of compression versus 165psi” for idling and full load denotes).
I do like your work and your persistence on this project.
What I try to figure out is the point of your project.
Thanks
Manolis Pattakos
"What is the point of your project?" -- That's a good question... it's been asked many times by other people. #1 is to prove that a running, functional version of the design can exist. It requires that you get a lot of things right to make it work on your first try without any major changes. I've seen several other people fail doing similar things. Nobody else has done this design in a car before either, short of the F1 car back in 2004 of which I've not seen any video proof of. #2 - It's a really cool and challenging project where I get to design something entirely to my specification that doesn't have an exact answer. What I mean by that is the valve timing could effectively be anything I choose and that greatly affects the performance. Also, it was a challenge to give the engine the best airflow. #3 - I had completed 3 previous design iterations on single cylinder Briggs and Strattons, with the 3rd being quite good and ran over 20 hours. We made 3 different sets of valves and floating seals for that engine and it was a lot of fun to see how the performance changed. #4 - I like big projects. I have 1000's of hours into this, just like some of my past projects (supermileage cars, combat robots,...).
I didn't choose a higher reving engine because that would cost more money and I really like BMW E36's. This car was well suited for the project. I should of done the 4 cylinder model to decrease the cost and complexity, but I figured the inline 6 would be more fun.
"It can’t be “50x”, not even “10x” - My M5 could go from 1.3 L/h to 140 L/h and it was naturally aspirated.
5 years on, it does not appear to have made it to the dyno, This design cannot and will not work as expected. The engine is "over ported" meaning it will never have a flatish power curve, will be horrendously wasteful of fuel, and will disintegrate under even medium loading. There is a very good reason rotary valves have not replaced poppet valves, and this is a good example. The nearest equivalent was the sleeve valve engine used mainly in low revving aircraft engines. This engine would not even pass the emissions test, given its total loss oiling system, required to prevent the rotary sleeves from seizing. A good try, but Im guessing this engine has been dismantled by now.
E36 328is? WTF is that?
It would be kind of cool if the rotary valves could be driven by electric motors that were controlled by a computer.
Echter scheiß !!!! So ein Fake Fake!!!!
haha exhaust leaks like no other