Rotary valve technology

[rotaryvalveman]

http://img580.imageshack.us/i/1040414.jpg/][/URL]

this is the first mockup of a four cylinder unit. the combustion chamber shape was far from ideal but later we packaged things better and got the ports to the two valves much smaller and had a much better shaped combustion chamber.

[rotaryvalveman]

By rotaryvalveman at 2010-07-03

this is a computer generated picture of the actual head I had the best results with. it was on a 450cc single cylinder unit and the picture is the head on it's side with the exhaust port visable and the exhaust side of the combustion chamber to the left. The drive mechanism is not seen but within the case is the secondry reduction of the 2:1 drive to give the final 4:1 we ran with.

this model was put into 3D CAD after we made it and it has to be said that we did it the other way around. we actually made this freehand on the fly and drew it afterwards with a few hand drawn scetches along the way and a little geomectric checks in 2D CAD as we went to get timmings somewhere near. Hey, time was short. we finished cutting metal on a Saturday morning and had it running by lunch. That was where we stopped almost a decade ago and never optomised it but now we will.

[Carlos]

THE DEVELOPMENT OF A VIABLE ROTARY VALVE ENGINE
© Copyright Ralph O. Watson, 1/2/2001

http://ralphwatson.scienceontheweb.net/rotary.html

[rotaryvalveman]

Carlos.

I have been looking for this article for a while. Many thanks. I have not finished reading it but will do today. Thank you.

[alelanza]

Rotaryvalveman,

Does your concept allow for throttling/load to take place at the valve level? ie w/o a regular throttle plate similar to bmw's valvetronic?

Regards,

Alejandro Lanza

[rotaryvalveman]

There is a facility later on to remove the throttle plate in it's present form all together and do it all with variable timming, but one step at a time.

Good question, though as this is the path to the holy grail in economical and efficient four stroke engines. I don't want to reveal too much but this is part of the reason why I want to continue with the rotary valve project as in itself it is a good idea but it is what it opens up in the way of previouse impossible compromises.

[autogyro]

Great work rotaryvalveman.
You have misgivings about reciprocating sleeve valves but continue with a reciprocating crankshaft, the sleeves are at half engine speed with four stroke applications. I would like to see the flow differences. Both sleeve and rotary must be much better than poppet valves
In anycase it is possible to use fully rotating sleeves or split sleeves on the Crecy concept with the cylinder liner stationary in the middle for best piston ring seal and a rotating exhaust sleeve at the top and inlet sleeve at the bottom.

Taking this to the logical non reciprocating ideal, it would be possible to design a wankel rotary blown two stroke with rotating valves/sleeves.
It would be a rich running and difficult to optimise unit but the answer to that would be to inject air and fuel into the exhaust to clean up the exhaust and to drive a generator in a hybrid application.
The throttle control and further optimisation would be achieved by augmenting the torque from the wankel engine by electrical means using an intigrated energy recovery and apply unit in the powertrain.
Must take a look at my patents again.

[xxChrisxx]

I cannot agree Chris when you say that comparisons cannot be made between engines of very different design concepts.

Then you must be comparing them in a very unscientific way. With multiple variables you cannot attribute what components cause gains and what cause losses. Basically you know what the differences are but not why they are different.

This is common sense, when you test something you change one thing only at a time and measure the difference.

You cannot compare a 4 stroke naturally aspirated poppet valve engine to a 2 stroke boosted sleeve valve engine and conclude anything meaningful about specific components. You can conclude that one package is better based on specific criteria, such as power to weight, power per volume etc.

So unless you are suggesting basically using a mini Crecy for an F1 engine and not just the sleeve valve arrangement, then a comparison is fair. If you are comparing both and using the Crecy to site an example of how superior a sleeve valve is the comparison is meaningless.

Even then you've got to look at the gains and weigh them up against the disadvantages. The BMEP performance of that setup is inferior to the boosted F1 engines of the 80's and only slightly higher than those of today. From what i've read the BSFC is higher for a sleeve valve than the equivilant poppet valve, and a 2 stroke doesn't burn as well as a 4 stroke.

So the idea is not just from a power, but from an emissions point of view does the switch have a net gain?

An interesting question to be sure.

is the SAE paper you refer to headed titled, "Rotary Valves for Small Four-Cycle IC Engines", paper number 891793. If so it is sitting on my desk in front of me and was written for the 1989 small engine technology conference in Milwaukee, Wisconsin. If you like I could scan it and send it to you for your review.

The one I saw was newer than that, it was early 2000's, but if you don't mind scanning it i'd love to have a read.


EDIT: As an asside, I love this thread. Makes me wish I was an innovative person who comes up with wacky new ideas, but my skills lie in rigorous analysis (which although important is rather boring).

[autogyro]

Hahaha wacky new ideas.
I love it Chris.
Your input on such a thread is invaluable.
Of course detailed scientific comparisons must be made.
Unfortuantely it is only people like rotaryvalveman and you Chris who have the experience and seem to be willing to put in the effort and time to do the work needed to ensure progress.
I am semi retired these days and well aware of the effort cost and night oil burning needed to undertake such projects.
It is why I have such respect for rotaryvalveman. It brings back memories.

[autogyro]

I do not think comparing the BMEP of a highly blown F1 engine from the 80's is a fair comparison of anything other than the capability of an engine design to stay together at such high forced outputs.
However this does establish a bench mark for many aspects of reliability when comparing sleeve and rotary valves.
Certainly many of the advantages of sleeve and rotary valves are negated at high boost levels.

[rotaryvalveman]

autogyro.
one of the main points is, sorry to say it, politics, as I am trying to bring about change. If, as R.C.Cross did from the late '30s to the mid '80s make a worthwhile design that was so different that is made packaging it leading to a costly change in the package, then you loosed the customer's interest. they then won't pass it on to the final customer, us in the street.
If I can get it inot the mind of the industry that not changing is actually forcing a more violent move to another technology, then I will have fulfilled my work. Didn't J.F.Kennedy say something like that. Those that resist the advance of development are responsable for the lurches in Scociety. Something like that.

So, rather than find the most radically efficient method of moving a steel box on wheels (hey, now where could that take us) I am settling on changing us further than even the manufacturers seem reluctant to go but is in fact a small step compared to electric cars.

Further, there are already a large number of piston blocks there now ripe for a retrofit which would save a great deal of rescources in making new engines.

Also, it is about as big a technical leep as the financial guys who run these companies will be able to understand,,,,maybe.

[rotaryvalveman]

Chris

I will get the SAE paper scanned this week and e-mail it or send it to you in what ever form you wish.

[xxChrisxx]

I do not think comparing the BMEP of a highly blown F1 engine from the 80's is a fair comparison of anything other than the capability of an engine design to stay together at such high forced outputs.
However this does establish a bench mark for many aspects of reliability when comparing sleeve and rotary valves.
Certainly many of the advantages of sleeve and rotary valves are negated at high boost levels.

What? The BMEP is the only simple way to compare an engines capacity to do work independent of displacements and configurations.

Therefore it's the only simple method to compare an engines output with a single number. High BMEP = more capacity to do work. Therefore a 'better' engine configuration. Note the BMEP doesn't take into account reliability or anything like that, just how much work a specific engine can do.

In qualifying trim with unrestricted boost they were putting out BMEPs of 131 Bar. This doesn't take into account that they fell to bits afterwards, and regulally during a qualy lap. It just shows that they made monsterous power for a unit that size.

[xxChrisxx]

Chris

I will get the SAE paper scanned this week and e-mail it or send it to you in what ever form you wish.

Cheers.

[F1_eng]

Ok, I think you need to be very careful now. You could end up losing out a lot financially, I thought you might have had more direction with the project than you were telling, but maybe not.

I hope you have set out very clear and definite outcomes and objectives for the project, documented so you can refer back to them when difficult decisions need to be made.

What do you feel the benefits of this engine will be compared to say, a highly turbocharged downsized engine which all manufacturers are working very hard to develop and optimize? What is it about the design that yields these benefits?
What is the target market for the engine?
Why do you think big car companies aren't working on an engine like this for themselves? They could very very easily say, lets have a quick punt, we'll put £2million in and see what happens. Within less than a month, they could have an engine running on the dyno, fully benchmarked, data collected ready for comparison. Do you not think they would have tried this previously?

I fear that the engine you could end-up with, will have benefits that the market is not looking for.
Also my original fears were correct, how can you possibly work on the fly on a project like this.
I usually hate rigorous planning, but you have to be methodical with a porject such as this.

I look forward to your answers.