INTERNAL COMBUSTION ENGINE CONTROL DEVICE

PROBLEM TO BE SOLVED: To provide an internal combustion engine control device capable of sufficiently reducing manufacturing costs required for preventing damage of an exhaust gas sensor by eliminating the necessity for an instrument measuring the quantity of condensation water accumulated in an exhaust pipe.SOLUTION: An exhaust pipe wall temperature estimation part refers to a supply heat quantity calculation map, a wall temperature addition value map, and a wall temperature subtraction value map, and calculates an estimated wall temperature in an exhaust pipe sequentially found on the basis of an exhaust temperature detected from an exhaust temperature sensor, a gas flow rate detected from an air flow meter, and an outside air temperature detected by an outside air temperature sensor. An exhaust pipe wall dew point temperature calculation part refers to a dew point temperature calculation map, and calculates a dew point temperature of the exhaust pipe found on the basis of an air-fuel ratio between the gas flow rate and a fuel weight. A condensation water quantity estimation part refers to a condensation water integrated quantity calculation map, and calculates a relative wall temperature on the basis of the estimated wall temperature and the dew point temperature, calculates a condensation water integrated quantity on the basis of the relative wall temperature and the gas flow rate, and performs the estimation by setting a value obtained by integrating the calculated condensation water integrated quantity as the quantity of the condensation water.