Electrically powered camshaft?
Electrically powered camshaft?
(OP)
Did anyone ever though of an electrically powered camshaft? It would remove the need for a timing belt/chain and it would then be a lot easier to have infinite variable valve timing. The only possible problem is the size of the electric motor we would need. I know it take around 20% of the power of an engine to drive the timing belt/chain so I'm not sure if it would be feasible





RE: Electrically powered camshaft?
While belts have a limited life and have common maintenance issues and chains can be noisy and occasionally have maintenance issues, a well designed gear will be very durable and reliable. Gear driven cams have existed on automotive engines since the 19th century. As this solution is very rare, w must presume i is lack of incentive rather than a lack of technology that gives us cam drives that need expensive maintenance or fail all to often.
Regards
Pat
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RE: Electrically powered camshaft?
RE: Electrically powered camshaft?
Chains, gears, belts guarantee no valve-to-piston collisions as long as components don't physically fail. Phase-shifting by conventional means only happens within defined mechanical bounds, so that there are no collisions.
Using a camshaft still locks you to the same lift and duration. I think your estimate of 20% of engine power to run the camshaft is way high, but whether it's run by mechanical means or by electrics, the power demand is still there.
Lots of disadvantages, no advantages that I can see.
RE: Electrically powered camshaft?
RE: Electrically powered camshaft?
I wonder if sleeve valves or equivalent will ever come back. If they do, there may be easier ways to alter their open area profiles dynamically.
- Steve
RE: Electrically powered camshaft?
The nice thing about a poppet valve is that, when sealed, the parts sealing against each other are not moving relative to each other. Keep in mind that the exhaust side is subject to an extremely nasty environment.
Some people find reliance on springs to close it (and avoid piston-to-valve collisions) to be disconcerting. There is an alternative ... Ducati's desmodromic system that uses another cam lobe to push the valve closed. But, expensive!! Springs work well enough for most people. Pneumatic valve closure works well enough for most of the rest.
It would be nice to infinitely vary valve timing and lift, but that gets complicated and expensive. (BMW Valvetronic)
RE: Electrically powered camshaft?
It's just that whenever I see a fully assembled multi-valve cylinder head (or worse, the bits all laid out) I find myself thinking "Bloody hell, that's complicated", whereas many of the best engineering solutions are beautiful in their simplicity.
- Steve
RE: Electrically powered camshaft?
direct injection, separate oil system,
its just that they got a bad name in the pollution area,
is this the way,??
regards Marcus
RE: Electrically powered camshaft?
RE: Electrically powered camshaft?
cheers malbeare
h
RE: Electrically powered camshaft?
Bill
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RE: Electrically powered camshaft?