To shorten the response time of a temperature sensor provided in an exhaust pipe regardless of change in operation mode of an automated car by measuring the actual temperature of the exhaust gas, and calculating a sensor signal using an algorism which uses a specified control parameter, for predicting temperature transition.

The axial temperature of exhaust gas is measured and the acquired sensor signal is calculate using an equation which uses an algorism that uses control parameters P, I, and D, for predicting temperature transition. Here, in an equation, Ucalculated is a calculated signal value, Umeasured is a sensor signal, P, I, and D are control parameters peculiar to application of PID controller, τ is time constant, and t is time. The function of a temperature sensor which is actually used, or, a usable value among actual engine data such as air mass flow, rotation speed, engine load, jetted fuel amount, ignition delay, cooling water temperature, and external temperature is used as the control parameters P, I, and D.