Patent ID: 8708071

Claim:
A cooling system for an electric vehicle, comprising: a cooling unit configured to cool an electric drive unit that electrically drives the electric vehicle; and a control unit configured to control the cooling unit, wherein the control unit controls the cooling unit in a first cooling mode that provides a first cooling capacity when a force for driving the electric vehicle is in a first operational region, and controls the cooling unit in a second cooling mode that provides a second cooling capacity that is higher than the first cooling capacity when the force for driving the electric vehicle is in a second operational region that is higher than the first operational region, in the second cooling mode, the control unit controls the cooling unit so that the second cooling capacity becomes higher as a rotational speed of the electric drive unit decreases, the rotational speed at which a highest operating efficiency point of the electric drive unit is obtained is higher than the rotational speed that yields a maximum value of the second cooling capacity, a temperature of the electric drive unit in the first cooling capacity does not exceed an upper limit temperature while the force for driving the electric vehicle in the first operational region is continuously generated by the electric drive unit, a temperature of the electric drive unit in the second cooling capacity does not exceed the upper limit temperature while the force for driving the electric vehicle in the second operational region is generated over a short time interval by the electric drive unit, the control unit is configured to calculate the force for driving the electric vehicle based upon a speed of the electric vehicle detected by a speed detecting unit of the electric vehicle and an amount of actuation of an accelerator pedal of the electric vehicle detected by an actuation amount detecting unit of the accelerator pedal, the control unit is configured to select the first cooling mode or the second cooling mode according to whether an operating point, determined by a torque and a rotational speed of the electric drive unit corresponding to the force for driving the electric vehicle, is within the first operational region or within the second operational region, and in the second cooling mode, the control unit is configured to control the cooling unit at the second cooling capacity that is proportional to an output generated by the electric drive unit.