camshaft torque vs speed

[woollymoof]

Hi All,

This has been on my mind for a while now.

Excluding friction, does the torque required to turn the camshaft(s) increase with speed of rotation? assuming steady state.

Cheers,

Kirk Veitch
Swinburne University of Technology 2004

[woollymoof]

Hi All,

This has been on my mind for a while now.

Excluding friction, does the torque required to turn the camshaft(s) increase with speed of rotation? assuming steady state.

Cheers,

Kirk Veitch
Swinburne University of Technology 2004

[Tim Heinemann]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by woollymoof:

Excluding friction, does the torque required to turn the camshaft(s) increase with speed of rotation? assuming steady state.

<HR></BLOCKQUOTE>


If you really want to exclude friction the torque stays the same as it's the (cross) product of force (in this case the valve spring) and lever (the cam) and both don't change with rpm (the fact that camshaft torque is inhomogeneous as a function of the number of cams is irrelevant IMHO). Obviously the necessary power therefore increases with rpm.



Tim

[Denny Trimble]

There might be a very small valve inertia term here (or large if it's a pushrod V8), which increases camshaft drive torque w/ RPM.
f=m*a
As RPM increases, valve acceleration on open increases, so camshaft torque has to increase with RPM. But, I'm sure overcoming the valve springs, and friction, are the more dominant forces.

University of Washington Formula SAE ('98, '99, '03, '04)

[woollymoof]

sort of what i was thinking, thanks guys

Cheers,

Kirk Veitch
Swinburne University of Technology 2004