Abstract: An ECU includes a motor control unit that controls energization to a motor, and a fixation determination unit that makes a determination on fixation of a valve body. The motor drives the valve body housed in a housing of a control valve. When the fixation determination unit has determined that the valve body is fixed, the motor control unit performs fixation-time control that energizes the motor so as to drive the valve body.

Abstract: A cooling device for an engine includes a radiator route passing through a radiator, that are merged together after being branched on the downstream side from the inside of the engine in a coolant circuit configured to allow a coolant to flow from a pump through the inside of the engine and return to the pump. An at-stop control section provided in the cooling device controls a multiway valve that has three discharge ports, including a radiator port connected to the radiator route, so as to close the radiator port and open at least one of the other discharge ports when an ignition switch is turned off.

Abstract: When both a position sensor and a motor malfunction, an ECU limits the engine rotation speed to such a speed range that the pressure inside a circulation route remains at or below a predetermined value even when the opening degree of a control valve is a minimum opening degree. When the position sensor is malfunction but the motor is not malfunction, the ECU relaxes the limits on the engine rotation speed, compared with when both the position sensor and the motor are malfunction, by driving the motor to an end of a motion range thereof and increasing the opening degree of the control valve to an opening degree larger than the minimum opening degree.

Abstract: An ECU includes a motor control unit that controls energization to a motor, and a fixation determination unit that makes a determination on fixation of a valve body. The motor drives the valve body housed in a housing of a control valve. When the fixation determination unit has determined that the valve body is fixed, the motor control unit performs fixation-time control that energizes the motor so as to drive the valve body.

Abstract: When both a position sensor and a motor malfunction, an ECU limits the engine rotation speed to such a speed range that the pressure inside a circulation route remains at or below a predetermined value even when the opening degree of a control valve is a minimum opening degree. When the position sensor is malfunction but the motor is not malfunction, the ECU relaxes the limits on the engine rotation speed, compared with when both the position sensor and the motor are malfunction, by driving the motor to an end of a motion range thereof and increasing the opening degree of the control valve to an opening degree larger than the minimum opening degree.

Abstract: A cooling device for an engine includes a radiator route passing through a radiator, that are merged together after being branched on the downstream side from the inside of the engine in a coolant circuit configured to allow a coolant to flow from a pump through the inside of the engine and return to the pump. An at-stop control section provided in the cooling device controls a multiway valve that has three discharge ports, including a radiator port connected to the radiator route, so as to close the radiator port and open at least one of the other discharge ports when an ignition switch is turned off.