Pneumatic Valvetrain!

[Mr 5 0]

gtsr515:

Generally, if I don't know the answer, I don't reply to the question (at least on technical forums; opinion forums like the Blue Oval Lounge are an entirely different situation). What's the point?

That said, we can't dictate what other folks choose to reply to or how they reply. I would suggest that if the reply isn't revelant to your question to just ignore it. If the thread gets off on a tangent, try it again, worded differently. Stay calm if possible.

I dug up some info from an F1 site that may help you out:

Pneumatic valve closing in modern F-1 engines is via a very high pressure air pump. The valves are opened somewhat 'normally' via a camshaft (or camshafts). The cams can open the valves OK but a phenomena called hysterisis prevents springs from acting quickly enough to provide rapid enough closure. Hence - Renault (might have been Peugeot) came up with the very novel idea of slamming the valves shut with high pressure air. That is .... the cam action is working against a constant, high-pressure air load on the backside of the intake and exhaust valves. When there's no cam acting upon the valve lifter ... the valve will close. This ensures that the closing of the valves is in exact following with the lowest point or "dead" profile of the camshaft.

Hope this helps.