Build Thread- Making A Rotary Valved Engine

[Dzuari]

Figured i'd share this on here, been posting and sharing this on some other forums for a while, some of you know me from my other build, the 671 Blower;

http://www.cnczone.com/forums/i_c_en...ercharger.html


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.

the background behind this design is; I came up with this idea back when i was 18 then shortly after i found out that others have attempted this, so for the past 3 years i'v been researching and developing. I actually have my first design printed out with our company's 3D printer but like a lot of ideas, they change very rapidly and are much different by the time you done with them.

For those of you who don't know me, I work for Phillips Patterns & Castings & Diamond P Industries (DPI) in Muncie, IN, an aluminum Foundry and Production CNC shop. We making American made parts, Im an engineer, Foundry worker, Machinist, pattern maker and i can take any design and turn it into full production(fairly quickly if you've been following my blower build )

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Now this build is going to be much slower than my others because this is still in design and prototyping and i also don't want to release much information on my design yet, but i will be documenting and posting all my work through my company and youtube channel when i feel i can, so sub if you interested in this stuff, cause i know a lot of you are.

dzuari's Channel - YouTube

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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.

[RICHARD ZASTROW]

Just FYI, (you probably already know this) there is a rotary valve engine company producing natural gas power plants. Check out Coates International Ltd.

They seem to have worked out there "teething" problems.

Dick Z

[Dzuari]

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

[JayDee80]

First post in this forum, so hello to all
@Topic:
Interesting thread! I really like the idea of rotary (or sleeve) valves, did a little research for myself during the last few years... Another interesting concept which was shelved some 50 years ago due to problems of that time (sealing, materials) and is just about to re-emerge (Bishop, Coates and a few others... ).

A few questions:
Why are you wanting to minimize overlap? And why should this be more efficient?
If you are not running an air restricted engine, a certain amount of overlap can actually improve efficiency, torque and emissions. "Just" a matter of how much overlap in what rev range and engine load (depending on how you tuned your intake and exhaust geometry). Variable valve timing should not be a bigger problem with rotary valves than it is with poppet valves. (On the other hand, variable valve "lift" IS more complicated).

[Dzuari]

Originally Posted by JayDee80 First post in this forum, so hello to all @Topic: Interesting thread! I really like the idea of rotary (or sleeve) valves, did a little research for myself during the last few years... Another interesting concept which was shelved some 50 years ago due to problems of that time (sealing, materials) and is just about to re-emerge (Bishop, Coates and a few others... ). A few questions: Why are you wanting to minimize overlap? And why should this be more efficient? If you are not running an air restricted engine, a certain amount of overlap can actually improve efficiency, torque and emissions. "Just" a matter of how much overlap in what rev range and engine load (depending on how you tuned your intake and exhaust geometry). Variable valve timing should not be a bigger problem with rotary valves than it is with poppet valves. (On the other hand, variable valve "lift" IS more complicated).

I don't want to minimize overlap per se, but i believe with my drastic valve opening and closing ramps that i can get the exhaust closed right at or before TDC, that way i can reduce overlap and depend more on the vacuum created by the decent of the piston to pull air in.

the only reason for valve overlap is to get the intake charge moving, but the more overlap you have, the more intake charge you will loose out of the exhaust before it closes. It will make more sense when i actually show what my engine looks like.

[JayDee80]

Thank you for the answer!
I'm curious to see your solution

[Dzuari]

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

[JayDee80]

Hm...
I still have a little bit of a problem with "more open time / area" + "less overlap" = better / more efficient... Please don't take this as a criticism!
I fully understand that you don't want to give away details at this early stage, but out of curiosity:

- What will be the purpose of this engine? Daily driver? Racing? If racing, what kind of? Drag racing? Circuit?
- Will the engine be turbo- oder supercharged?
- Will it be a completely new engine or a new head bolted to an existing block (brings its own advantages and difficulties)?
And:
- What do you want to prove with this project? That it works? Or that it is better than existing solutions?
- Did you do work with an engine simulation software, e.g. Ricardo Wave, GT Power or AVL Boost to calculate your port areas, timing, mass flow, flow velocity?

Again: Best of luck (from a guy who is atm designing a new crank-/transmission case for a motorcycle cylinder head & engine internals)!

[Dzuari]

Originally Posted by JayDee80 Hm... I still have a little bit of a problem with "more open time / area" + "less overlap" = better / more efficient... Please don't take this as a criticism! I fully understand that you don't want to give away details at this early stage, but out of curiosity: - What will be the purpose of this engine? Daily driver? Racing? If racing, what kind of? Drag racing? Circuit? - Will the engine be turbo- oder supercharged? - Will it be a completely new engine or a new head bolted to an existing block (brings its own advantages and difficulties)? And: - What do you want to prove with this project? That it works? Or that it is better than existing solutions? - Did you do work with an engine simulation software, e.g. Ricardo Wave, GT Power or AVL Boost to calculate your port areas, timing, mass flow, flow velocity? Again: Best of luck (from a guy who is atm designing a new crank-/transmission case for a motorcycle cylinder head & engine internals)!

It was originally intended just as a high end street engine, but we will be pushing it as far as it can go, wouldn't complain if we could get 1000-2000hp for drag . We are debating on building a LSR now that the east coast land speed is moving to Ohio, so it might suit that.

can't go into detail on the induction of the engine

There is two version i have so far, one will be able to mount to an existing engine. The other one will be an engine designed completely around the head.

I don't have any engine simulation software, i tried some lower end stuff but my engine is so much different than anything else, that i feel it wouldn't even get me accurate enough data to make good decisions. The only 'flow' simulation i have right now is floXpress in solid works, it does basic pressure variations but thats about it. I can apply forces to my designs and test strengths and weakness too. But, since im able to make patterns and molds, its more time effective for me to just design it, run a few simple sims, make a few variations, test then analyze.

I can calculate port areas with solidworks just by taking cross sections. mass flow and flow velocity i can calculate on my own, only in one specific point in time during engine operation of coarse . the excel calculator that i created will give me timing.

[holbieone]

Originally Posted by Dzuari I don't want to minimize overlap per se, but i believe with my drastic valve opening and closing ramps that i can get the exhaust closed right at or before TDC, that way i can reduce overlap and depend more on the vacuum created by the decent of the piston to pull air in. the only reason for valve overlap is to get the intake charge moving, but the more overlap you have, the more intake charge you will loose out of the exhaust before it closes. It will make more sense when i actually show what my engine looks like.

the overlap is there to cool off the exhaust valve

[Dzuari]

Originally Posted by holbieone the overlap is there to cool off the exhaust valve

I've got that covered

[JayDee80]

Originally Posted by holbieone the overlap is there to cool off the exhaust valve

This is one reason for overlap. Which, of course, you don't need with many of the rotary valve designs.

Other reasons are, as Dzuari mentioned above, "dynamic supercharging" of the engine (exhaust moving out of the engine (and pressure waves/pulses being reflected in the exhaust system and back in the cylinder head) create more vacuum in the cylinder, thus "sucking more air in" than the descent of the piston alone could achieve, simply speaking (Sorry for the language, I'm German. Sometimes I may not have the right words in the back of my mind).

And: With correct valve timing you can create an "internal" EGR, leaving exhaust gases in the cylinder / flowing exhaust back into the intake to have a kind of inert gas present there. Apart from getting better emission values if you get it right, you can drive at, let's say, 1/3 throttle with the throttle butterfly actually much more open. This results in better efficiency due to less throttle losses. Of course this needs electronically controlled throttle and variable valve timing (if you have variable valve lift additionally (BMW Valvetronic, Fiat Multiair for example) you don't need a throttle device at all).