bursty

Hey all,
I was writing a paper for a physics class, comparing the Rotary Engine to a typical 4 Stroke Piston motor. The primary advantage the rotary has is that there is no valvetrain at all. In an article i found, Ford stated that 70% of the restriction in an engine is due to the valvetrain, and i was thinking of how to combine the rotary's efficiency in a new head design for piston motors.

This is what i came up with, so tell me if I'm insane, or if this is common knowledge, or whatever, just gimme feedback.

One way the rotary gets around having to deal with a valvetrain is they implement ports, instead of valves....just bigass holes which allow a direct charge of airflow....no turbulence at all. So I got to thinking about what causes the turbulence in the valves? Well its the shape of the valve; ie the air has to flow around the head of the valve instead of being a direct shot. So what could i do to prevent this turbulence? Then it hit me....butterfly valves. If there could be some way to incorporate a butterfly valve into the heads, you could eliminate the turbulence caused by the air flowing around the head of the valve, giving it more of a direct charge, in turn allowing more air flow ie more power....

So what do ya think?

1BADFNZ

How would you activate the valves?? What's going to open and close them??

Not bashing you just presenting a problem for ya

felton316

Doesn't some of the Subaru boxer engines have valves like that?

F1_SS

the rotart motor has so many problems with it that its not even funny. 1. The rotary motor was first developed back in the day so its old technology. 2. Since there are no pistons and crank and connecting rods the displacement on the rotary is not EXACTLY known, it kinda a derived guess. 3. the rotary motor creates alot of smog. 4.The rotary engine creates extreme heat

foff667

iTrader: (2)

what do you think a pushrod motor is? lol I just got a kick out of that one

P Mack

iTrader: (6)

It would be hard to make butterfly valves work because the high pressure in the combustion chamber would try and fold them in half and they wouldn't seal very well. Traditional valves don't have that problem because the combustion chamber pressure presses them up against the valve seat so they seal well. There's another design called spherical rotary valves though, check out www.coatesengine.com

JL ws-6

iTrader: (50)

I never really thought that rotary valve thing ever worked. Surprised it's still around. I wonder if you could somehow put a port in the side of the cylinder like a 2 cycle to enter air/fuel mixture, and have a valve only for exhaust release. That may work, and there would be alot less moving parts. Or, if you could somehow activate valves with a solenoid, rahter than a camshaft. No more cam changes, change the computer, you could go from a 50 mpg car, to a 600 HP car with the switch of a program. It would take a better man than me to figure out how to make it work, I just come up with the ideas.....

F1_SS

Its old technology but it works. i would rather bend and replace pushrod than bend a connecting rod and replace that.

MUSTANGEATER

iTrader: (10)

I think this is a good idea but going to take a lot of time and thinking out of the box to make it work. Unmodified and Naturally aspirated Rotary's are rather reliable motors. However once you get 1 degree of knock retard boom bye bye apex seal. The coolest part of a Rotary is you can brake your motor and drive the car home lol

1BADFNZ

That's been worked on for some years now. They're just having problems with it. The problems they're having (or were having) was they couldn't get the solenoid's to open and shut fast enough. It will work on a low rpm engine but for high rpm's and such a camshaft is still sooo much faster.

Z06PSI

iTrader: (33)

Formula 1 is getting the electromagnetic valves soon. They are still testing them. In testing they are getting 24k Rpms. The way it works is a spherical ball with a hole drilled through it rotates on a axis and is turned by electromagnetic pulses on opposite sides of the ball. It is all computer controlled and mechanical loss is cut down considerably. Piston movement is the only dedicated mechanical device in the motor. Right now they use pneumatic valves on their 3.0 ltr v-10 850 h.p. motors that will survive 19k rpm's...

The solenoid is being skipped becuase of its mechanical properties.

bursty

They way i had planned to actuate (sp?) the valves opening and closing is by still using the rockers but just have them push down on one side of the butterfly valve, causing that side to dump and the other to lift...ie opening the valve

The one issue i didnt think about was the sealing of the valve. That would definitely present a problem


Thanks for feedback though guys

SSactionLs1

NA rotary motors are some of THE MOST RELIABLE ENGINES EVER. Its when you put boost to them that they get unreliable.. and by inreliable i mean bad design from mazda as far as heat extraction.

SSactionLs1

You could have a long shaft the length of the head controll them electronicly.

TAQuickness

iTrader: (28)

I was discussing this with a friend about 6 months ago... A high speed ball valve would be your best bet.

Asuming you could get the reliability from the ball valves, how would that effect the over head design?

Jammer

iTrader: (1)

I think you could be onto something... just need a team of 5 guys and 10 million bucks..a superior lab and several years...but you are onto something

Keith

by saying pnuematic valves I think you mean the valve springs. The valve springs are actually containers filled with air to whatever seat pressure they want. The best part about doing it that way is that air never fatigues like steel or titanium does at those high cyclical rates like around 19,000 rpm.

The killer set-up would be a electrically driven rotary vlave setup. LIke the Coates Spherical Rotary valves. But then you have to worry about reliability and synchronization of the vales with the engine. BMW has taken te next step with it's variable lift valvetrain. There is no throttle valve(butterfly) in the way, so there is no restriction in the intake tract just smooth nonturbulent air.

Steve - Race Eng

iTrader: (1)

www.roton-engines.com

Download the pdf file which explains the concept of their rotary valves.

Also, issue #4 of "Race Engine Technology" magazine has a nice technical article on the heads with great photos.

You can order back issues of "Race Engine Technology" from EWA in New Jersey.

Steve Demirjian
Race Engine Development

LS1PoweredZ28

iTrader: (2)

That is freakin awsome.

Kevin

B T

I see that has already been posted

I gotta slow down and read.

My bad!