Rotary Valve Engines and seals? (design)

Some companies, especially alternative technology companies, are about attracting grants and investor money rather than the technology itself. You can see in this thread how people are persueded by something that seems better but actually isn't. If you already want something to work, a good presentation is very persuasive. If that wasn't so there would be no infomercials. I don't know anything about the Coates company, but they have been around a long time, potential users have dismissed their concepts, yet they continue to promote themselves and stay in business. Nothing illegal about that, but it's something to think about.

 

Just to clarify, im not asking anyone to invest or trying to persuade anyone. this thread was started in the hopes of getting some ideas from some people that know a lot more than me and have been around a lot longer, and it has helped out a lot.

 

Been a while since i've posted on this but figured i'd update, some of you know me from my blower build,

http://www.jalopyjournal.com/forum/showthread.php?t=636663

I talk about my prototype engine on some of my videos but i figured it wouldn't hurt to share this and i know some people will find this really interesting.

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been working on my design a bit and after about 9 hours of banging my head against my computer trying to figuring this out, i finally have graphed my valve porting and timing. Unfortunately i can't go into detail on the mechanics of my design or how i'm doing all this, you'll just have to believe me and trust that im not bs'ing .

before you start looking though i'd like to explain that this graph is not valve lift(rotors), this is a graph of the percent that the valve is open in relation to the crankshaft position.

Example: 160° BBDC on power, exhaust Opens, at 180°BDC the exhaust valve is about 70% open(not a mistake), so 70% of port area(4.4")= 3.08" of port area, 5-10° ABDC the port is fully open and is held open till about 310°(50°BTDC), so the exhaust port(4.4") is open 100% for 120° of the exhaust stroke.

Can't tell you how i'v achieved this but i can control how long i hold the valves open, overlap, intake opening and closing, exhaust opening and closing and how fast they open and close. Because of this, with a little tweaking, i can close exhaust and open intake within about 5-15° of overlap and control the percent of how much the ports are open during the overlap, and have the ports fully open for the duration of the cycle.




I just threw together a poppet valve comparison to the left to give a perspective of the port area difference, the piston bore on the poppet is 4"D and the valve is 2"D with 0.50" resulting in 3.33" valve area at full lift(the red cylinder). You can see the difference in port area compared to my design (yellow area, it is to scale)

So in comparison, a cam and poppet valve is always 1/2 the speed of the crank, so no matter what speed the engine is at, the valve is always either lifting or closing at a relative speed to the crank.

If i took the time to graph the poppet valve, i would have to create a point cloud of the percent area that the port is allowing flow in relation to the crank position, so the poppet valve would only achieve 100% port opening for a millisecond at the top of its lobe, where as, i can hold mine fully open for how ever i long i want.

on top of that, my RPM redline is only limited to how much air i can get into the cylinder before the valves close, and since i can hold 180° compression and power, i can harness more power out of the explosion before the valves open, and less overlap also mean more efficient too.

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Now im not happy with this graph, to much overlap and i want the intake to stay open a little longer, but i spent about 5 hours staring at numbers trying to figure this all out, then 3 hours doing only to realize i screwed up, then 3 more fixing it, so i don't really want to make another one right now.

Once i get my valve timing how i want it, im going to design the engine based off it then print out a scaled prototype with our printer just to make sure everything fits correctly, then ill go through the same processes that i did with my other builds and get a working prototype, then after i feel its working well, ill move on to manufacturing single, v twins, V4 then V8's.

 

here is my second graphing, took me about 4hrs, but i'v figured out all the equations need to calculate the point cloud so tomorrow ill be able to make an excel program to create the graph a lot faster.

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here is my second graph, changed around the ports a bit and tweaked the rotors.

Rotary Valve Ports = 5.04" Area(fully opened) (dark red/blue)

2.18" Poppet 0.75" Lift = 5.14" Area(fully opened) (blue)
2.18" Poppet 0.50" Lift = 3.47" Area(fully opened) (light Blue)

2.0" Poppet 0.75" Lift = 4.71" Area(fully opened) (red)
2.0" Poppet 0.50" Lift = 3.14" Area(fully opened) (light red)



I'd like to note that my rotors are designed around a cylinder bore somewhere in the range of 4", i threw in the 2.18" poppet on the intake side because i race a 489bbc with that size intake, if i where to adjust my rotors to fit a 489, the Total area would raise to 6.08", thus the rotor lines on the graph would be raised up above the 6" line(but i don't want to spend another 5 hours drawing them )

I like this graph more than the first, but i can adjust them more so that i hold fully open ports fast in the cycles. Im also only running 20° of overlap...



Right around the overlap point, both ports are open to an area of about 1". i'd also like to say in regards to cross flow design of the overlap, that my port center lines(what would normally be valve stem center line for poppets) are about 160° apart. almost 180° apart from each other, and since i don't have a poppet valve that my intake charge has to flow around, i will have extremely efficient overlap, and my duration of 20° is probably to much. A 2" Poppet valve is around a half inch of area at the point of overlap but, have a longer duration.

In comparison to cross flow, i believe the 426 hemi has a valve stem offset somewhere around 90-120°, don't quote me on that though.

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Sometime during the week im going to adjust it so that my intake valve opens extremely quick, that way i can rely more on the vacuum of piston descending instead of overlap, making the engine more efficient. Ideally id like to close the exhaust right at TDC, leaving the cylinder with the least amount of air(theoretically ) which means the decent of the piston will produce a decent vacuum, and hopefully be able to have the intake port 40-75% open within 10°, maybe only running 1-2° overlap. We'll c though

 

Pics?

 

starting to sound like a willys knight sleeve engine

 

http://forums.beyond.ca/showthread/t-142394.html
the K-cycle engine,rotary cylinders,one intake valve one exhaust valve and one spark plug.six cylinder engine.my brother in law did some machining for this engine.

 

Dzuari,
I haven't carefully studied the info you posted, but you seem to be comparing your rotary valve port area to a poppet valve with a smaller open area(or max flow). While that comparison may result in better numbers for your set-up, that doesn't mean it has better time vs area numbers talked about in earlier posts. Comparing the time/area of your valve to a poppet valve set-up with the same max area(or flow) is the comparison to make. It might take a multi-valve head to equal what your set-up can do, but that's the apples to apples benchmark your idea needs to equal or exceed.

 

I like thinking about stuff like this but it makes my hair hurt.

 

wow, thats a very interesting design, seems like a lot of parts, but if i've read correctly, it was developed in the 60's, which means that metallurgy and special coatings have advanced tremendously since then which that would make something like that a lot more reliable. I'd love to see photos of this and some kind of diagram of how it works.

Do you know if anyone is currently trying to create one? If not, i would consider trying to create a small working model if i could get the required info on how it works.

 

i've found this photo of the engine



but how does the linear force of the pistons create rotational movement?

 

the comparisons are based off of valves from an engine of similar CI, my engine was designed around a chevy 350, so i choose a 2in valve as a median since you can fit valves around 2" in a 350.

here are some more graphs i've made that give a comparison of a 2" and a 2.18" with .5 and .75 lift. Since these graphs though i have produced a excel program using a bunch of formulas i created to graph my valves by just changing a few numbers, took me about 20hrs to make . still dont have the formulas in the calculator yet but i will.

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here is my second graphing, took me about 4hrs, but i'v figured out all the equations need to calculate the point cloud so tomorrow ill be able to make an excel program to create the graph a lot faster.

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here is my second graph, changed around the ports a bit and tweaked the rotors.

Rotary Valve Ports = 5.04" Area(fully opened)

2.18" Poppet 0.75" Lift = 5.14" Area(fully opened)
2.18" Poppet 0.50" Lift = 3.47" Area(fully opened)

2.0" Poppet 0.75" Lift = 4.71" Area(fully opened)
2.0" Poppet 0.50" Lift = 3.14" Area(fully opened)



I'd like to note that my rotors are designed around a cylinder bore somewhere in the range of 4", i threw in the 2.18" poppet on the intake side because i race a 489bbc with that size intake, if i where to adjust my rotors to fit a 489, the Total area would raise to 6.08", thus the rotor lines on the graph would be raised up above the 6" line(but i don't want to spend another 5 hours drawing them )

I like this graph more than the first, but i can adjust them more so that i hold fully open ports fast in the cycles. Im also only running 20° of overlap...



Right around the overlap point, both ports are open to an area of about 1". i'd also like to say in regards to cross flow design of the overlap, that my port center lines(what would normally be valve stem center line for poppets) are about 160° apart. almost 180° apart from each other, and since i don't have a poppet valve that my intake charge has to flow around, i will have extremely efficient overlap, and my duration of 20° is probably to much. A 2" Poppet valve is around a half inch of area at the point of overlap but, have a longer duration.

In comparison to cross flow, i believe the 426 hemi has a valve stem offset somewhere around 90-120°, don't quote me on that though.

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Sometime during the week im going to adjust it so that my intake valve opens extremely quick, that way i can rely more on the vacuum of piston descending instead of overlap, making the engine more efficient. Ideally id like to close the exhaust right at TDC, leaving the cylinder with the least amount of air(theoretically ) which means the decent of the piston will produce a decent vacuum, and hopefully be able to have the intake port 40-75% open within 10°, maybe only running 1-2° overlap. We'll c though

 

I'm not an expert but I'd expect it used a wobble plate. Fastening engine though.

 

here's the formulas I've come up with, but im not going to discuss what any of it means . Now i just need to transpose all this into excel, and it should automatically create my points for me on my graph.



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Got the exhaust side of my calculator done, intake is somewhat started.

Kind of hard to see the lines but ignore anything above the flat line across, that line indicates that the port is fully opened. The straight up white line is TDC, my splines also go below 0 so ignore anything past that to.




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Some more graphs, just messing around with different configurations



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Added a valve overlap degree formula, exhaust opens 30° BBDC and closed at TDC with 10° overlap. Exhaust port is fully open by BDC and held fully open for 140° of the duration with a total port area of 4.21





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Also, im not to excited about the actual overall area that i can open, i'm more focused on the extremes of the valves opening and closing, in this last graph, my ports go from completely closed to fully open in 30° of the crankshaft, all before BDC.

 

reading more on the engine, it seems one of the problems people talk about is the oil being flung to the outsides because of the centrifugal force even at low rpms, but since the engine acts as a giant flywheel storing a tremendous amount of energy, you could spin it at very low rpms and use some special coatings i know about that would almost let it run completely dry(no oil), also, since it seem to run very cool, not even liquid cooled, would also help the coatings longevity.

I could design and machine all of this if i could get so good drawing on the engine.

 

interesting stuff!

found this on a tangent of reading that k-cycle link

the info-mercial vibe is nauseating but i still like just looking at the engine parts around 6:10 and onward

http://www.youtube.com/watch?v=uJSLDq7MkhQ

 

now your talking ,,,,sea furys built IN AUSTRALIA,,,aledgedly the only piston engineded machine to shoot down a jet ,,,during the Korean war,,,,,got a belly tank from one laying round the hangar somewhere!!! AN fittings with whitworth hardware,,,,,,as said already look up the dunstan rotary valve head in australia,,,,,theres still a few working around aus in 6cyl hydro boats,,,,primitive for you im sure ,,,but double check their procesess as the answer may be looking you in the eye,,,,plus there are guys here playing with recasting the old heads and im sure their having simila issues and a brains trust on this issue is a good thing

 

think silver coatings,,,,,,we use silver coated nuts on tubines etc,,,and if you can get the truth from lycoming or from turbomecca ,you may find the metal used on turbine wheel shaft coatings may not really be unobtainium,,it might just be a silver alloy ,,,,turbines spin 10 times faster than your engine will (no disrespect intended)

 

i may be wrong but look up "epicyclic gearbox"

 

If you build a better mouse trap ,,,the big 3 may just shut you down!!! Dad was an aircraft engineer as well and blue printed a head design in the early sixties ,,,and mum still h***les him for not putting a patent on it,,,it later was thought of by another aussie,,look up Ralf Sarich Orbital engine,,,,he got shut down by paying him out 60million in the early 80s,,,,,dad still reckons his version was better and i think it is a bit like old fishing stories,,,,,, good luck and id like to place my order in advance for a pair of heads for a SBF 289!!!!!!
In all seriousness look aviation for your answers,,,,,for seals and materials etc,,,,i love your concept and wish you all the best for its developement,,,very exciting times for you i think

 

Yes, it does work off a swash plate arrangement, much like a modern A/C compressor. I'd be more concerned about long-term sealing of the combustion pressure in the rotating chamber.

Garen, would you discuss how you are getting these long "max lift" dwell times and fast closing ramps with the rotary valves? I understand that it's all in the valve port shape, but it still needs a period of time (deg of rotation) to get it shut...? Maybe I missed it in the thread, but I'm ***uming the rotary valves are still mechanically timed to the crankshaft?

BTW, the transaxle is back on hold...finally got my hands on the relevant pieces of the T56, and it's WAY too long as I designed it (29" from axle C/L to rear cover). I'm looking at ways of making it shorter or other trans possibilities.

Thanks for the help. Hijack over...

 

sry, cant discuss any part of how im doing it. im kind of in the dark on how i should make these valves though, i don't know what is going to happen with opening them so fast. the initial exhaust pressure wave is going to be crazy, i need to start reading into exhaust resonance and harmonics, the only other comparable engine that can produce such drastic valve openings is F1(that i know of) and im not comparing it to F1 by any means but pneumatic valves are the only thing that come to mind with such drastic ramps, and i'll probably never get hold of any info on what kind of duration those things run . So my best bet is to just make them, test, test and retest.

The one disadvantage i have though from my design, my heads cant be machined out of billet, i have to make patterns and coreboxes to be able to get a prototype :/.

 

I'm in contact with a company that does all kinds of coatings like that, up to 3000°+, im not going to skimp on any part of my engine, pretty much everything that moves or has hot/cold gases running through it is going to have some kind of special coating on it. I can get coatings that resist up to 1200° and have a Rockwell hardness of 70-80, in comparison, low grade steal is around mid 30's and high carbon is low 40's. This means i can run a steel seal against a coated aluminum surface and the steel will wear out before the housing does.

they also inhibit metals from seizing or welding together. So even if my engine over heats and locks, just have to wait for it to cool down and it will start right back up.

It truly is fascinating to see all the things that coatings make possible, and so many people don't even know they exist. I actually found this company by accident, they just happened to walk into our shop right when i was at the front desk, if that didn't happen id probably wouldn't even be pursuing this build.

 

call me paranoid, but that more of a worry about that than my engine not working, i think i have a plan though .

 

Have you posted on Speedtalk.com?

 

Just registered, thanks.

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Finished the intake formulas, changed around some numbers.


On this one the Exhaust opens 10° BBDC, is fully open 10° ABDC and is held open for 140°, closing at 10° ATDC.

Intake opens about 5° BTDC, full open by 20° ATDC and held for 40°, closing about 5° Before BDC.

With a total port area of 4.71"



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I like this one more though. only 4.21 port area but the intake is open a lot long with less overlap and give the power a full 180° stroke.

exhaust open: BDC
Exhaust held full: 120°
Exhaust Close: TDC

Intake Open: 8° BTDC
Intake Held Full: 140°
Intake Close: 3-5° ABDC

 

Go Garen GO!
You might be on to something big here!

Just a thought, with the fairly recent coming of direct fuel injection, what about direct AIR injection as well? Electrically driven high pressure air injected into the cylinders?

 

Not directly on point to your question, but the following link shows just how long the rotary engine concept has been around: http://en.wikipedia.org/wiki/Gnome_Monosoupape

 

wait till you see my design.

That is an interesting concept, eliminating the intake port, you would want have your fuel injectors spray into the air lines just before entering the cylinder to atomize the air. you could use a turbo or centrifugal for high end boost and the electrical for low rpm, that would make the engine extremely efficient at low rpm, but the faster it revs, the more air it would need, you would have the use a large injector to keep the engine from starving and idk if the intake charge would heat up to much going through the nozzle to cause premature detonation. Plus getting all the components to work right would be a nightmare and expensive.

I've been looking into a thing call the GEET engine concept, pretty interesting on the intake side but can't really find and hard data on it. I have a briggs and start 5.5 layin around somewhere, might rig it up and build one. not to complicated from what i've read.

 

That's not the same thing as an automotive (****el) rotary, or what Garen is developing. Here's one running if anyone's interested...
http://www.youtube.com/watch?v=-UBAukXPD-0

This is something a little closer (I think? )
http://cnettv.cnet.com/coates-spherical-valvetrain/9742-1_53-32534.html