Other

Toyota Jidosha Kabushiki Kaisha

Aisan Kogyo Kabushiki Kaisha

Hiromichi Murakami

Daisuke Yamamoto

Yoshikazu Shinpo

Isao Takagi

Shigetaka Yoshikawa

Hiroshi Suwahara

An engine cooling system includes a flow control valve and an electronic control unit (ECU) for controlling the flow control valve. The flow control valve regulates the flow rate of coolant flowing through a radiator in a coolant circuit. The ECU feedback controls the opening size of the flow control valve such that the temperature of coolant at an engine outlet seeks a predetermined target value. During the feedback control, the ECU controls the flow control valve such that the opening size of the flow control valve remains above a predetermined lowest value. As a result, the flow control valve is prevented from falling in a small opening size range in which in which it is difficult to cause the engine outlet coolant temperature to seek the target value, and the engine outlet coolant temperature is favorably adjusted.

Engine cooling system

An engine cooling system controls a cooling degree of an engine according to an operating condition thereof by circulating cooling water through the engine. This system is provided with a water temperature sensor for detecting a cooling water temperature THW , a flow rate regulating valve for regulating a circulation flow rate of the cooling water, and an electronic control unit (ECU) for controlling the valve . The ECU sets a non-control region and a first and second control regions, each centering on a target water temperature to be calculated according to operating conditions of the engine . The ECU controls the valve to open and close at a high speed when the cooling water temperature THW is in the second control region, thereby to allow the cooling water temperature to approach the first control region or at a low speed when the cooling water temperature THW is in the first control region, thereby to allow the cooling water temperature to approach the non-control region, or holds the valve at a current opening degree when the cooling water temperature THW is in the non-control region.

An engine cooling apparatus includes a flow regulating valve, which adjusts a flow rate of a coolant passing through a radiator provided in a coolant circulation passage of the engine, and an electronic control unit (ECU), which controls an opening of the flow regulating valve such that an engine outlet coolant temperature reaches a necessary target temperature. The ECU sets a basic opening as a feedforward term based on the operation state of the engine. The ECU calculates a final opening from an F/B constant as a feedback term, which is increased or decreased such that the engine outlet coolant temperature reaches the target temperature, and the basic opening. Further, the ECU performs feedback control on the opening of the flow regulating valve based on the final opening. As a result, the responsibility of the coolant temperature control is improved.

Engine cooling apparatus

An engine cooling system controls a cooling degree of an engine according to an operating condition thereof by circulating cooling water through the engine. This system is provided with a flow rate regulating valve for regulating a circulation flow rate of the cooling water. An electronic control unit (ECU) controls the valve to open at a predetermined opening when determining the engine as being stopped. In this opening control, the ECU controls to bring a valve element into contact with a valve body once and then move the valve element to determine the predetermined opening with reference to a full-closed position of the valve element.

A flow control valve is located in a coolant circuit that extends through an engine. The flow control valve is operated in accordance with a control mode selected from a full closing control mode, a full opening control mode, and a feedback control mode. When switching from one control mode to another, the flow control valve is controlled in accordance with a transitional control procedure selected from different types of transitional control procedures. The transitional control procedure to be performed is selected depending on which control modes are performed before and after the control mode switching and/or the current condition of the engine. Transitional controlling of the flow control valve is thus appropriately conducted.

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Obu, Japan

Hiromichi Murakami