Jim favours the delete key above all others and so recently deleted the cam on the intake of his car (he is dead after all)...

Jim realises that what is left is an automatic valve that opens and closes at just the right time (even on forced induction engines)...

Jim decides to leave the exhaust valve alone...
-- madness, Nov 03 2005

In case you wondered it is the weight of the valve that has made this impossible in the past... A heavy valve will remain open for some time after BDC so will loose some charge volume (and hence cylinder pressure).

Ok so how lightweight can a valve be made... hollow/vacum titanium ceramic?
-- madness, Nov 03 2005


Mmmm. Hi-tech wipers, blades, and washer.
-- reensure, Nov 03 2005


Ok --- my brain hurts --- are you talking about a hanky?
-- madness, Nov 03 2005


If the valve is made using several concentric overlapping rings held fixed at the centre on the valve stem --- the stem would not move and so is not part of the "valve" weight.

This will limit the valve lift so perhaps the stem should extend into the cylinder --- (causing disturbance to gas flows in the cylinder?).
-- madness, Nov 03 2005


This idea was used on several kinds of radial engines and I think maybe on large diesel two stroke engines for ships. These all had the intake valves inside the piston itsself, though. For most applications, this wouldn't work so well. Maybe some kind of one-way valve would work best here, or is that what you meant in the first place?
-- discontinuuity, Nov 03 2005


Jim would be disappointed by the amount of unburnt fumes escaping out of his one way intake valve before it closes, because of valve float.
-- RayfordSteele, Nov 04 2005


Jim ponders for a moment --- well direct injection will solve the unburnt problem... Jim is prepared to accept some loss of cylinder pressure.
-- madness, Nov 04 2005



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