F1 Valve and Cam Question

[RacingManiac]

well this is an old thread and new info are hard to come by in terms of specifics....

[Kozy]

As far as I can asscertain from recent journals on the sunject, F1 engines have always had camshafts, an entirely camless engine cannot operate fast enough and is nowhere near reliable enough for the speeds required in F1.

The pnuematic spring system works as a conventional spring would to shut the valve as the camshaft moves around, but does so without the 'float' common with conventional springs at high rpm. The pnuematic system effectively slams the valves open very aggressively, far more so than any metal spring could ever hope to achieve.

Totally camless engines are coming, but I think they are a long way off in terms of being commercially viable. To limiting restrictions at present regarding the favoured soleniod operation are the size and power requirements. Typically a solenoid will be optimised for one thing, travel, speed or force. An engine requires all three of these to be maximised, which is a tall order for anything that is to fit in the space of a conventional camshaft system, especially with the current 12-14v limitation on power.

Fully hydraulic/pnuematic systems I do not know so much about, but I gather they also carry their own limitations, particularly with regards to force and speed.

[revetec]

Basically....Springs have rebound at higher duty cycles, pneumatic equivalents don't (well it is negligible) so more accurate valve operation is possible at very high RPMs.
Kozy...I wouldn't say the valve slams open, rather that it opens and closes as designed, by the camshaft grind, at higher RPMs.

[Matra et Alpine]

Originally Posted by revetec

Kozy...I wouldn't say the valve slams open, rather that it opens and closes as designed, by the camshaft grind.

yeah the open is always driven by the cam profile. THe close however is determined by the strength of the spring and at high revs can leave the profile and will bounce. F1 use penumatics to close and cam to open.
Ducati love Desmodronic whcih pushes in both directions -- and hence it's drawback too

[revetec]

Ah yes...but until valve bounce occurs (usually 500rpm before it is audible) the camshaft totally determines closing rates.