| 摘要 |
The invention controls the opening of an oil control valve (OCV), which controls the operation of a variable valve timing mechanism in an internal combustion engine, according to a duty ratio of a driving pulse signal. An electronic control unit (ECU) performs feedback control on a duty ratio DR of the driving pulse signal during ordinary operation based on a target value and an actual value of the valve timing. When the oil temperature is low (i.e., when the operating oil viscosity is high), the ECU controls the valve timing of the engine by repeating an inching operation that maintains the duty ratio DR of the signal at a large value (i.e., 0% or 100%) for a predetermined hold time so as to operate the variable valve timing mechanism, and then maintaining the duty ratio DR of the signal at a value (50%) that does not operate the variable valve timing mechanism.
|
