Rotary valve technology

[rotaryvalveman]

hi. I want to raise the question of rotary valve engines again. Iknow it is an old subject to some and others think it may have no political or engineering value but I have my reasons for this. I do have an axe to grind but I would like to ask others thier opinion on this matter, bth in and out of the light of F1. I am going to build a running unit, done it onece before in the UK but doing it from Australia now as I am sick of the politics and knockdowns but here it seems people like to see you "have a go" just for the hell of it. I will leave that fuse lit ans see where we go.

[autogyro]

There are some interesting rotary valve ideas, however the only type that entered production in any worthwhile application was the sleeve valve aero engines of the 1940s and early 1950s.
IMO these valve systems are still superior even to F1 valve systems.

[Belatti]

You can find info here:

viewtopic.php?f=4&t=7486&hilit=rotary+valve

viewtopic.php?f=4&t=3045&hilit=+rotary+valve

[rotaryvalveman]

yes, i could but these forums are now quite old and things have moved on. I know that the rotary valve may have been a more common thing now if it had not been for politics such as the supposed cost saving V8's in F1 that killed the most serious move on the subject from Ilmor with the RV V10 but that is my point. My project was killed 7 years ago due to damned politics so now I am doing it my way and without help from anyone so I can do it in my time with my own money. The technical side of things is interesting but what I cannot understand is why certain elements of the industry (and you know who you all are) have tried to dampen a technology that would actually keep the supposed status quo in keeping internal combustion engines viable using new fuels etc. I don't want to use the word "conspiracey" but I was offered by a camshaft manufacturer a number of years ago to buy me out and then found out from a friend in the comapny they were going to bury it. Why will the industry not embrace something that keeps the piston and crank alive. Anyhow, on the more technical front, I am looking forward to docile engines that easyley run on the street at 12:1 or higher that are physically smaller and lighter than any current production engine could ever hope to achieve with clean emmisions. I will let you guys open the pandoras box on that as I have seen you all have some great ideas. I am still not sure what timings to try first this time as the last time it seemed that a 260 degree inlet and 265 Exhaust acted more like a full race profile would and also, with even the slightest amount of overlap, it would not start. It seemed that all I learnt about engine parameters went out of the window and as an example, ignition timing was almost TDC. I will let you all think about that one. I have my own theorys as to why that would be tha case.

[Carlos]

Rotary valve 4 stroke inlet/exhaust port timing may exhibit similarities with two stroke I/E timing.

Two Stroke Tuners Manual
By G. Jennings
http://www.vintagesleds.com/library/man ... ndbook.pdf

Insight:
"The advantage of a rotary valve is that it enables the two-stroke engine's intake timing to be asymmetrical which is not possible with two-stroke piston port type engines. The two-stroke piston port type engine's intake timing opens and closes before and after top dead center at the same crank angle making it symmetrical whereas the rotary valve allows the opening to begin earlier and close earlier.

Rotary valve engines can be tailored to deliver power over a wider speed range or higher power over a narrower speed range than either piston port or reed valve engine. Where a portion of the rotary-valve is a portion of the crankcase itself it is particularly important that no wear is allowed to take place."

From:
http://en.wikipedia.org/wiki/Two_stroke_engine

Make note of Uniflow Scavenged Engine timing diagram.

Thread Belatti kindly researched and specifically recommended:
malbeare:
"Valve timing Intake open 20° BBDC 520° close 60° ABDC 240°
Duration 440° (this is not a mistake)
Maximum port area at 20° ATDC
Exhaust open 40° BBDC 500° close 60° ATDC 60°
Duration 280°
Maximum port area at TDC 0°
Overlap 260° (this is not a mistake)"

Well worth your time to study previous thread.

Also G Jennings section on ignition timing.

OT - Interesting saying 'Axe to grind' - here we answer that with the folk wisdom 'It's easy to hang a corpse' and of course the modern equivalent ... 'It is what it is.'

Good Luck

[F1_eng]

You can get very close to optimal with theroetical hand calculations, or better still use CFD to look at how the gas behaves at various timings, this would certainly be the method I'd use.

"engines that easyley run on the street at 12:1 or higher that are physically smaller and lighter than any current production engine could ever hope to achieve with clean emmisions."

Briefly, how are you setting about trying to achieve these claims?

[xxChrisxx]

OP I really am not a grammar Nazi (as I have less than stellar grammer [edit: and spelling, it would appear] myself), but people would pay more attention if you used paragraphs.

How people write on forums is acutally a really good reflection of how they think and express themselves in the real world. Your second post was quite rambling and almost came to tl;dr.

[rotaryvalveman]

on the grammer and paragraph note, point taken but it had been a long day and was just about to finally get some shut eye, but I appologise.

On the timming section, Iam doing a four stroke, not a two stroke.

On the CFD side, we tried to go to the top of the tree a fiew years ago and went to the internal analysis company of an F1 team in, shall we just say the centre of England. They even went back to fluent CFD and tried to get the program re-written but came to the concusion that the question was just too big and too expensive to answer with computers and building one was going to be cheaper.

So, in answer to another question in, how am I going to prove this all is the best thing since sliced bread, well I am going to build another one and run it.

If i start with peramiters that work for a medium performance poppet valve engine and edge in different directions but build in the adjustability (air flow level, overlap, timming in relation to TDC, timming in relation to valve opening, etc) then this way I will learn what is fact, not prediction.

Don't get me wrong, I am not afraid of computers and the like but it seems that the industry has become a victim of it's own success so now, old fashioned experementation is actually going to be cheaper and quicker.

The axe I have to grind is that the last time I did it for a customer who promptly went bust and left me with the development bill. Hey, if it don't kill you it makes you stronger but after the results I saw in those early days, I decided I would one day go back to it and now is that time.

[WhiteBlue]

I read http://home.people.net.au/~mrbdesign/PD ... echBRV.pdf to get some idea of the issue. If the technology is interesting for road car design and leads to greater fuel efficiency it should be applied to the new engine formula for 2013.

[rotaryvalveman]

that would be nice but I think politics will get in the way under the guise of cost saving but I do have some understanding in this. In my view they should cap costs but not invention. if they tell you that you can spend X,Y,Z on this or that but leave the design open, sure we could get one on the track. I would love to have the oportunity.

In the mean time, I have picked the Yamaha 5-valve 250cc and 450cc single cylinder unit to start with and will make a desicion on the next unit such as a 4 inline or V6 but we will see on that.

[rotaryvalveman]

on the 2stroke timming thing, that may have come accross a bit blunt. What I meant was, I don't think that the two are compatable but, hey, give me 12 months at this and I may change my mind.

[WhiteBlue]

that would be nice but I think politics will get in the way under the guise of cost saving but I do have some understanding in this. In my view they should cap costs but not invention. if they tell you that you can spend X,Y,Z on this or that but leave the design open, sure we could get one on the track. I would love to have the oportunity.

The new turbo engines with direct injection will be completely new engines anyway. So cost should not really be an issue if the fuel efficiency is improved with new valve technology. Do you think that the valves will be efficient in direct injection engines?

If Yes, why would the gas exchange be better than with conventional poppet valves?

[xxChrisxx]

If Yes, why would the gas exchange be better than with conventional poppet valves?

Wouldn't flow rates be higher for a rotary valve as you dont have a stem in the way at 'max lift'? (I suppose fully open would be the rotary equiviant).

[rotaryvalveman]

yes,,, that is exactly the point of why I got involved in this in the first place. the track we can make with a twin rotor head is so straight that there is no such thing as "porting" required. in fact when it is open, you can see the centre of the piston. also you do not have the drag of the camshaft valvetrain. I was once told that the Ford DFV F1 engine was calculated to loose 100BHP just to turn over it's own cams. the Rotary valve draws less than 5ft pounds to turn over.

Airflow is way above what you can get with conventional vlaves but also there is the fact that the poppet valve is no longer sitting in the combustion chamber like a red hot penny on a stick. this, I feel, is the source of the lack of pre-ignition and knock, ability to run higher compression ratios and the fact that historically, rotary valve engines have always needed far less ignition advance than conventional engines.

I am, however, having no preconceptions in all of this and we are ready to learn more.

[WhiteBlue]

It sounds like a very valuable technology to have for the new direct injection engines. So advantage are:

• less mechanical losses compared to current technology
• no obstacles inside the cylinders for gas fill, less disturbance of fuel charge and ignition
• no objects in the air stream, better air fill and aerodynamic losses

I would be surprised if Ferrari, Merc, Renault, VW and Cosworth would all miss out on having such an advantage. I expect VW to enter F1 if the regulations allow a I-4 design.