control system and method for variable valve actuation system

摘要

A method of controlling a variable valve actuation system is provided. A cam assembly (52) is operated to move an intake valve (32) between a first position where the intake valve (32) blocks a flow of fluid and a second position where the intake valve (32) allows a flow of fluid. At least one operating parameter of the engine (20) is sensed. A valve actuation period is determined based on the at least one operating parameter. A valve actuator (70) is engaged with the intake valve (32) to prevent the intake valve (32) from returning to the first position in response to operation of the cam assembly (52). The valve actuator (70) is released to allow the intake valve (32) to return to the first position at the end of the determined valve actuation period.