Temperature control device for internal combustion engine

1. A temperature control device for an internal combustion engine, wherein the device is applied to a system that includes:

the internal combustion engine, which has therein an engine passage, which is a passage for coolant;

a cooling circuit, which is arranged outside the internal combustion engine and is coupled to the engine passage;

an electric pump, which is configured to circulate the coolant;

a water temperature sensor, which is arranged in the internal combustion engine; and

an ambient temperature sensor, which is configured to detect an ambient temperature, which is a temperature of gas surrounding the internal combustion engine,

the temperature control device comprising:

a determining drive processor, which is configured to drive the electric pump when a difference between a water temperature detected by the water temperature sensor and an ambient temperature detected by the ambient temperature sensor is greater than or equal to a predetermined value while the electric pump is stopped; and

an abnormality determining processor, which is configured to determine that at least one of the water temperature sensor and the ambient temperature sensor is abnormal on a condition that a decrease amount of a water temperature detected by the water temperature sensor that results from driving the electric pump by the determining drive processor is less than or equal to a predetermined amount, wherein

the determining drive processor includes a stopping processor, which stops driving of the electric pump when a cumulative amount of the coolant discharged from the electric pump reaches a predetermined cumulative amount with driving of the electric pump by the determining drive processor, and

the predetermined cumulative amount is set according to an inside volume of the engine passage between an inlet of the engine passage and the water temperature sensor.

2. The temperature control device for an internal combustion engine according claim 1 , wherein, when power consumption of the electric pump is large, the stopping processor assumes that the cumulative amount of discharged coolant has reached the predetermined cumulative amount when a shorter period of time has elapsed from when the determining drive processor started driving the electric pump than when the power consumption of the electric pump is small, and the stopping processor stops driving the electric pump based on that assumption.

3. The temperature control device for an internal combustion engine according claim 1 , wherein

the determining drive processor is designed to vary power consumption of the electric pump, and

the stopping processor includes a cumulative amount determining processor, which determines whether the cumulative amount of discharged coolant has reached the predetermined cumulative amount based on one of power consumption of the electric pump and a rotational speed of a motor incorporated in the electric pump.

4. The temperature control device for an internal combustion engine according claim 3 , wherein

the cumulative amount determining processor includes a discharge amount calculation processor that calculates a discharge amount of the electric pump per unit time based on one of the power consumption of the electric pump and the rotational speed of a motor incorporated in the electric pump, and

the cumulative amount determining processor determines whether a cumulative amount of the discharge amount calculated by the discharge amount calculation processor will reach the predetermined cumulative amount.

5. The temperature control device for an internal combustion engine according to claim 1 , wherein the predetermined cumulative amount is an amount of coolant that is greater than or equal to an amount of coolant inside the engine passage.

6. The temperature control device for an internal combustion engine according to claim 5 , wherein the water temperature sensor is arranged in an exit portion of the engine passage of the internal combustion engine.