Single Valve Engine?

[Rolls]

I just had an idea, a single valved engine, eg one massive valve on each cylinder, then a second valve or even throttle body in the intake that closes when the exhaust stroke is occuring.

The logistics of this surely would be no more difficult than a typical 2 valve head, it would just require a different valve design for the intake, the increased surface area of the valve would surely be beneficial?

[Blackkers]

[zebra]

[Ben C34]

Paint shop detail drawings pls.

Edited April 30, 2014 by superben

[Rolls]

Anyone got any actual thoughts on whether the increased surface area could help with cylinder filling/emptying?

[Rolls]

Problems I can see so far are the valve would have to operate at double the speed of a normal valve, you would also always get some form of overlap due to the valve cavity where the intake/exhaust meet, though if coupled with direct injection you could remove this.

Edited April 30, 2014 by Rolls

[89CAL]

How are you expecting this to work? have the top of the combustion chamber open to the part of the manifold where the valve is? Because if so you will add all that extra combustion volume - Therefore reduced C:R. Not to mention the issues with heat

If the air is bought in through the side then you lose a bit of volume for the air to be sucked in (proper term is escaping me atm :S)

It's not a good idea, there is a reason they use conventional style valves in engines. Over the years the valve size/location/etc to improve the way the engine performs

I just cant see a way for this to work any better at all

[Dale FZ1]

Direct injection 2 stroke as trialed by the Sarich Orbital group. That would only have one set of valves. Supercharged for scavenging purposes. At least that makes it eligible for the Forced Induction section.

All pie in the sky stuff.

[zebra]

Trialled?

They are in production is the Ossa enduro bikes

and Honda is meant to be releasing one next year

And...well...they have a reed valve I guess

[Dale FZ1]

Reed valves still count.

Stand corrected on this gear hitting series production units.

I have a suspicion it (or something similar) was also seen on Evinrude outboards

[zebra]

Can buy DI kits for 50cc RC aircraft engines too

[GTSBoy]

One huge negative is that the exhaust valve is hot, the exhaust flow path after the valve is hot. You don't want intake charge flowing over/through hot surfaces.

The overlap problem mentioned above is a real one. There can be no overlap at all when you have to flow exhaust outward, then completely stop that flow before you can start intake flow going the other way. Sure, overlap is only needed because we are restricted by breathing capacity of current designs and this monovalve idea HOPES to provide massive increase to breathing. But I strongly suspect that you will never get enough extra breathing from it to eradicate the need for an overlap period in high speed engines.

[Leroy Peterson]

if you want to play with engine design and have science help you out along the way...

http://automationgame.com/

highly recommend it. design an engine (inline 4, inline 6, v6, v8, turbos), design the car, choose suspension, wheel options etc. still in beta. plenty of more content to come.

[zebra]

Fun little game that