Abstract: A method for monitoring operation of a solenoid valve having an armature and a poppet coupled to the armature includes the steps of energizing a coil in the valve to generate a current signature reflecting current vs. time, detecting a first inflection point in the current signature, wherein the first inflection point occurs when the armature starts to move from one of the open and closed positions toward the other of the open and closed positions, and detecting a second inflection point in the current signature. The second inflection point occurs when the armature moves completely to the other of the open and closed positions. In one embodiment, the first inflection point indicates when the valve begins to open, making it possible to accurately determine the elapsed opening time of the valve.

Abstract: A pressure swirl atomizer includes a nozzle having an exit orifice and a plurality of tangential swirl channels and a pintle that is movable within a pintle bearing between a closed position that closes the exit orifice and an open position that opens the exit orifice. The atomizer also has a pole piece having a channel, and the pole piece and the pintle are separated by an air gap when the pintle is in the closed position. A space between the pintle and the pintle bearing, the air gap, and the channel together form at least a part of a return path. Fluid from the tangential swirl channels drains through the return path when the pintle is in the closed position. To open the atomizer, a solenoid generates a magnetic force when energized, attracting the pintle toward the pole piece into the open position. A check valve disposed in the return path generates a fluid back pressure when the solenoid is de-energized to push the pintle toward the closed position.

Abstract: A pressure swirl atomizer includes a nozzle having an exit orifice and a plurality of tangential swirl channels and a pintle that is movable within a pintle bearing between a closed position that closes the exit orifice and an open position that opens the exit orifice. The atomizer also has a pole piece having a channel, and the pole piece and the pintle are separated by an air gap when the pintle is in the closed position. A space between the pintle and the pintle bearing, the air gap, and the channel together form at least a part of a return path. Fluid from the tangential swirl channels drains through the return path when the pintle is in the closed position. To open the atomizer, a solenoid generates a magnetic force when energized, attracting the pintle toward the pole piece into the open position. A check valve disposed in the return path generates a fluid back pressure when the solenoid is de-energized to push the pintle toward the closed position.