How to reduce clutch wear on disengagement?
This is a general question about using an automotive-style clutch to spin up a stationary load with a piston engine by slipping until the load has reached the speed of the engine.
Intuitively, I would say the amount of wear on the clutch during the spin-up depends on three things:
#1. The length of time during which it was slipping (more time = more total wear)
#2. The speed difference between the load and the engine (more RPM difference = greater wear rate)
#3. The force normal to the friction pads (i.e. pressure between pressure plate & flywheel) during slipping (more pressure = greater wear rate)
My question is, if RPM is kept constant, what strategy minimises wear on the clutch during engagement? Gradually releasing the clutch with engine kept at low power/torque (big #1 and small #3), or dumping the clutch more rapidly with engine set to higher torque/power (small #1 and big #3)?
P.S. In this system the clutch is operated by an automatic controller that keeps engine RPM constant during slipping, by varying clutch plate pressure (aka clutch engagement). So point #2 remains constant regardless of strategy, and #1 and #3 are taken care of proportionally. The only user input is engine throttle during the initial spin-up.