Apparatus for controlling internal combustion engine

An apparatus for controlling an internal combustion engine, comprising:

• an exhaust gas sensor that detects a specific component in the exhaust gas of the internal combustion engine;
• a heater that is attached to the exhaust gas sensor and that can promptly activate the exhaust gas sensor and maintain the exhaust gas sensor in an activated state;
• and
• a control device that executes air-fuel ratio feedback control based on a detection result of the exhaust gas sensor in the activated state, and in a case in which the internal combustion engine is shut down, stops energization of the heater at a predetermined timing after shutdown of the internal combustion engine,
• wherein the control device sets the timing for stopping energization of the heater after shutdown of the internal combustion engine, to a point in time when a predetermined time set based on outside air temperature has elapsed or a point in time when cooling water temperature of the internal combustion engine has dropped to a predetermined temperature,
• wherein the control device includes a first control unit that controls the internal combustion engine, and a second control unit having a control command function for instructing the first control unit,
• wherein the second control unit sets the predetermined time based on the outside air temperature, and measures the elapsed time since shutdown of the internal combustion engine, and performs a first determination of whether the measured elapsed time has reached the set predetermined time, while the second control unit performs a second determination of whether the cooling water temperature of the internal combustion engine has reached the predetermined temperature for determination of a decrease in water temperature set beforehand, and also transmits a signal for cancelling heater energization, to the first control unit based on these two determinations, and
• wherein the first control unit stops energization of the heater upon reception of the signal for cancelling the heater energization.