Formula 1 valve timing

[sachinc99]

Hi I want to know abt the valve timing in f1 engines.
And also the valve timing diagram

Sachin

[riff_raff]

Static or dynamic?

[majicmeow]

Seeing as the valve timing in these engines is fixed, wouldn't that mean that it is always static? Perhaps I am missing what you mean...

If the intake valves are static timed to 15degrees BTDC, they are ALWAYS going to open at 15d BTDC. Overlap, duration and lift cannot change.

I doubt very much that the manufacturers would release sensitive information about valve timing for their engines, as those figures would be substantial to the performance of the engine.

Just my 2¢...

[pedaltometal]

Too bad, i'd love to get a cam ground to the same specifics as an F1 cam for a chevy V8... I think that wouldn't work well
Edit: Come to think about it, it just wouldn't work at all since F1 is 4OHC chevy is SOHC...

[riff_raff]

majicmeow,

Static valve timing means the valve follows the cam profile precisely. But at the speeds/inertias an F1 valvetrain operates at, the valve and bucket lifter are probably in actual contact with the cam lobe only during the initial lift period. As the lifter moves across the cam "nose" at higher speeds, it literally jumps by design. Thus creating a crude form of variable valve timing and lift.

[majicmeow]

Ah, I understand what you mean. Static by design, Dynamic by consequence. Neat way to look at it! Thanks for the insight

[PlatinumZealot]

But isn't that the reason why the have pneumatic springs? to prevent valve lift?!

So what happened to variable valve timing? that does not exist in F1 anymore?

[Ray]

But isn't that the reason why the have pneumatic springs? to prevent valve lift?!

So what happened to variable valve timing? that does not exist in F1 anymore?

If I'm not mistaken pneumatic valve springs were introduced to increase the revs, not to prevent valve lift. At the speeds the engines run metal springs would never work, and I doubt that a Desmodromic valve system would work either. I also believe VVT is against the rules. Some technological wonder F1 is huh?

[timbo]

Some technological wonder F1 is huh?

Yeah, can I mention NASCAR? Oops, sorry...

[Belatti]

Some technological wonder F1 is huh?

Yeah, can I mention NASCAR? Oops, sorry...

And again and again

If you keep laughing at NASCAR you will turn into NASCAR! -the Bernie warlock said

Oh!!! Its already happening! Old technology engine standarization! Night races! What else? Oval tracks?

[majicmeow]

Pnumatic valves were nessessary to prevent valve float, a problem inherent in high reving engines. With 19000rpm on tapetal valve springs would never do the job. The two issues go hand in hand. Likewise the pnumaric system would not be needed as an added complexity if the engines only ran at 9 or 10 thousand rpm.

[riff_raff]

The pneumatic valve spring does a lot of things.

A high operating frequency with a metal valve spring produces all sorts of crazy vibratory modes in the coil spring. When you get to valve operating frequencies above 100Hz (around 13,000 rpm) these spring vibratory modes can seriously affect valve motion and also over-stress an already highly-stressed metal spring. The mass of the metal valve spring itself also adds to the inertial loads in the system.

The beneficial characteristics of a pneumatic valve spring are that it is somewhat self dampening, it is lighter than a metal coil spring, it is slightly more compact than a metal coil spring, and most importantly the spring rate it provides can be actively varied simply by changing the system's feed pressure. This allows lower valve spring rates at lower operating speeds, thus producing less valvetrain friction loss and more power.

[Saabjock]

But isn't that the reason why the have pneumatic springs? to prevent valve lift?!

So what happened to variable valve timing? that does not exist in F1 anymore?

valve bounce.

[PlatinumZealot]

yeah that's what i meant.. valve bounce.
(lift )

There is no metal spring that can meet the acceleration requirement?

[xpensive]

One rather important feature with a pneumatic valve-system is that it has no serious hysteresis,
when the air never really changes pressure or volume.

Deforming metal elastically has, why it causes internal friction and as a consequence, heat.