pnumatic valve system on cars??

[adam2007]

do they use this instead of springs on road cars? or is it down to relibilty. I mean an evo fq400 packs 400bhp from 2.0 turbocharged engine, if they have pneumatic valves could that be doubled? they have performace parts by HKS. do formula one engines use HKS parts?

sorry about the spelling.

[n smikle]

The horsepower to drive the valve-train will be independent from the the engine horsepower for the most part, So the pnuematic valve springs will only free up a maximum amount of power. Not that much!

I hear that pneumatics valve springs are very leaky. I imagine you need air tight seals and those seals would have a high sliding velocity, so that is complicates things.

There might be other systems required to run them.. I would like to hear the other details though.

[PNSD]

F1 cars use pnumatic valves because at about 12,000 - 13,000rpm ( i think!! ) spring values become useless because they can not move quick enough. I think thats the reason anyway!

[ISLAMATRON]

F1 cars use pnumatic valves because at about 12,000 - 13,000rpm ( i think!! ) spring values become useless because they can not move quick enough. I think thats the reason anyway!

exactly! pneumatic valves allow the engines to rev as high as they do, thus greatly increasing the hp.

[CMSMJ1]

F1 cars use pnumatic valves because at about 12,000 - 13,000rpm ( i think!! ) spring values become useless because they can not move quick enough. I think thats the reason anyway!

It has to be a bit higher than that as my motorbike revs to 15.5k revs and uses steel springs in a double coil arrangement.

The problem is that you get valve float where it basically does not know whether it is coming or going.

There are no road cars able to rev anywhere near high enough to need pneumatic valves.

The Honda S2000 is a high revving motor - over 9000 revs I think..

[ISLAMATRON]

rotaries rev higher, but we have no use for springs

[majicmeow]

brap brap brap...

high revving 13B... beware of flying apex seals!!!

[ringo]

Any one has any images or details of the pneumatic system?

[Giblet]

Google F1 pneumatic valves?

Nope... cuz the first link you get is from Scarbs, one of the residents here.


http://scarbsf1.com/valves.html

[ringo]

Good stuff.
I'll go implement it on my briggs/stratton lawn mower now. 22k revs

[gibells]

Have F1 engines ever used desmodromics like Ducati engines use? I'd be quite interested to see whether they do because over in Motogp Ducati win the power race hands down, and I believe the concensus is it is because of the desmo system (using even less power than pnuematic valves?).

[safeaschuck]

Desmo isn't all gain's their are some disadvantages, cost and reliability spring (cough) to mind.
The faster the engine is going to rev the stronger the valve spring tension needs to be, as mentioned before about float, it's when the spring isn't strong enough to push the valve back down fast enough before the next stroke, having just consulted Wikipedia I can also add that springs, when of constant thickness and coil spacing have harmonic issues at certain speed ranges, hence the use of multiple or progressive springs on more modern motors to give a damping effect.

Desmo pushes the valves open and pulls them closed again doing away with a spring all together, and I BELIEVE frees up slightly more power at lower RPM where the springs have to be very oversprung in order to function correctly at high speed, however it needs to power the valve into the closed as well as open positions so at certain points will be less efficient, or as the lads on the eng-tips forum put it:

"Conventional valvetrain power requirements are proportional to speed (friction dominant), whereas desmo requirements are purely inertial. So there is a crossover point"

Could never formulate that sentence on my own...
http://www.eng-tips.com/viewthread.cfm? ... 426&page=4

Meaning a valve spring is as good if not better than Desmo at high speed, then there is another crossover when you reach the limits of the metal of the spring, to pneumatic.

[kilcoo316]

Did Renault ever roll out their Solenoid valves onto the F1 cars, or was that a stillbirth project?