Patent ID: 7089895

Claim:
An apparatus for operating a plurality of valves in an engine, the apparatus comprising: a plurality of valve actuators coupled to the plurality of valves, each valve actuator operable to move a respective valve, a plurality of accelerometers operable to detect an acceleration of the respective plurality of valves; a knock sensor operable to detect an acoustic impulse made by the valves when they seat; and a controller coupled to the valve actuators, accelerometers and sensor, the controller correlates signals from the sensor and accelerometers, wherein a signal from the sensor that correlates in time with a signal from an accelerometer indicates seating of the respective valve, which indicates a closure of the respective valve, and wherein the controller measures an magnitude of the acoustic impulse to be used as feedback in controlling the operation of the respective valve actuator, wherein a magnitude of an acoustic impulse that is measured above a second threshold level indicates closures of at least two valves at substantially the same time.