[b3lha]

Harvey,

I'm not wishing to get in the line of fire here, but could you clarify further.

Suppose the solenoid starts off closed and is then activated at a 10% duty cycle as per your diagram above. One cycle being 1/50th second = 20ms.

From my reading of your description, the initial 2ms pulse is enough to open the solenoid slightly, opposing the spring and the oil damping. But the remaining 18ms is not enough time for the spring to even slightly close the solenoid because of the oil damping? And then the next pulse hits and keeps the solenoid in its current position, not opening it any further?

It sounds like the spring tension and the level of oil damping must be very very accurate for this to work. A 2ms pulse at 1A opening the solenoid by exactly 10%. A worn spring or thinner/thicker fluid could cause significant variations. Does the TCU self-calibrate in some way?

From my purely theoretical standpoint, I can understand the idea of the solenoid oscillating such that averaged over any given time period, it is fully open for 10% and fully closed for 90%. But I can't yet grasp how a duty cycle can maintain the solenoid at an exactly defined partially open position.

Phil.