Oil control valve degradation detection and cleaning strategy

A hybrid-electric propulsion system of a vehicle, comprising:

• an engine including at least one cam coupled to a cam phaser, the cam phaser configured to adjust the cam between hard stops, the engine further including an oil control valve hydraulically coupled to the cam phaser;
• an energy conversion device configured to provide motive force to drive the vehicle;
• an energy storage device including a battery;
• and
• a control system configured to adjust engine operation, including shutting down engine operation during vehicle operation;
• and to adjust valve timing of the engine by adjusting the oil control valve during engine operation, the control system further configured to adjust the oil control valve responsive to cam position based on a first relationship during a first mode, and to adjust the oil control valve responsive to the cam position based on a second relationship during a second mode, the second relationship including abrupt switching of the oil control valve between two states responsive to the cam position with the second relationship including more abrupt adjustment than the first relationship, the second mode including operation of the cam away from the hard stops, and the second mode occurring during selected engine operating conditions, wherein the second mode includes switching the oil control valve between two states, each near an end region of the valve actuation, and switching based on cam position thresholds, where the thresholds are adjusted based on at least one of a commanded cam angle, an engine temperature, a valve position, and a measured cam angle.

A method for operating an oil control valve coupled to a cam phaser configured to adjust a position of at least one cam between hard stops, the oil control valve included in an internal combustion engine having an intake valve and/or an exhaust valve controlled via the cam phaser, the engine coupled in a vehicle having an electric machine configured to drive the vehicle, the method comprising:

• selectively shutting down the internal combustion engine and driving the vehicle with the electric machine;
• during engine operation, operating the oil control valve responsive to cam position feedback information, the oil control valve adjusted based on the feedback information;
• and
• during engine operation, operating the oil control valve in a cleaning mode during select conditions by abruptly switching the oil control valve between two states, the oil control valve adjusted more abruptly in the cleaning mode than during non-cleaning conditions, the abrupt adjustment including abruptly switching commanded states of the oil control valve between a first and second extreme state in response to a parameter exceeding an upper limit of deviation or a lower limit of deviation, to clean the valve in the cleaning mode, where the upper and lower limits of deviation are adjusted responsive to an operating condition, and where selection of the cleaning mode is responsive to a quantity of engine shut down operations.