Control device of an internal combustion engine

A control device of an internal combustion engine, comprising;

• an operational condition detecting means for detecting an operational condition of the internal combustion engine;
• a valve moving apparatus provided with a first valve control mechanism having a hydraulic valve characteristic changing mechanism for changing valve operation characteristic of at least one of a suction valve and an exhaust valve of said engine, and an oil pressure changing valve for changing pressure of a working oil supplied to said valve characteristic changing mechanism from an oil pressure source;
• a first valve operation control means for controlling operation of said oil pressure changing valve in accordance with the operational condition detected by said operational condition detecting means;
• control amount holding means corresponding to said respective valve operation characteristic with hold control amounts to control combustion condition of said engine;
• a combustion control means operated based on said control amount of said control amount holding means;
• a working oil property detecting means for detecting property of said working oil;
• a holding time setting means for setting a delay time between change of oil pressure by said oil pressure changing valve and completion of change of valve operation characteristic by said valve characteristic changing mechanism based on property of said working oil detected by said working oil property detecting means and;
• changing means for changing said control amount holding means to a control amount holding means corresponding to a changed valve operation characteristic when said delay time elapses after said oil pressure to be supplied to said valve characteristic changing mechanism is changed by said oil pressure changing valve.