| 摘要 |
PROBLEM TO BE SOLVED: To improve compatibility of VTC (valve timing control) overheat protection and securement of engine performance.SOLUTION: A threshold is set in respect to a statistical value calculated in sequence on the basis of a history of operating amount from an engine starting time of an actuator for changing a cam phase of VTC and it is determined whether or not a VTC driving limitation for overheat protection of the actuator is performed in reference to a value comparison between the statistical value and the threshold. Since the threshold is different depending on a temperature state of the actuator at the time of starting the engine, it is determined whether or not a temperature of atmosphere in the actuator is more than a prescribed temperature T(S201). When the temperature of atmosphere is more than the prescribed temperature T, the threshold is set to α(S202). When the temperature of atmosphere is less than T, a surplus state is generated in an allowable amount of a statistical value in respect to heat-proof limit of the actuator, so that the threshold α is set to αlarger than the threshold α(S203). With this arrangement, when the overheat protection is not required, frequency for limiting the driving of VTC is reduced. |
