Electric fan system for vehicle

Abstract

An electric fan system for a vehicle including two electric fans (10, 20) arranged in parallel in a vehicle width direction so as to blow cooling air to a radiator (100) and a condenser (110), wherein the electric fans are driven by a brushless motor (12) and a brush motor (22), a first drive voltage V1 for driving the brushless motor is set so as to increase in accordance with an increase of a water temperature (Tw) of the radiator or a coolant pressure (Pc) of the condenser, and simultaneously a second drive voltage V2 for driving the brush motor is set so as to increase monotonously as a value lower than the first drive voltage, whereby the two electric fans can operate simultaneously at all times, unevenness of the distribution of the flow rate can be reduced, and the drive voltage of the brush motor is reduced, so the lifetime can be extended and, further, provision is made of an electronic control unit (40a) for preferentially operating the electric fan (10) driven by the brushless motor over the electric fan (20) driven by the brush motor based on the temperature of the engine cooling water and the electric fan (10) driven by the brushless motor is designed to cool by cooling air other vehicle-mounted parts besides the radiator (100) and the condenser (110), specifically for example the ECU box (410).

Description

CROSS REFERENCES TO RELATED APPLICATIONS [0001] This application is based upon and claims priorities of Japanese Patent Application No. 2004-352743, filed in the Japan Patent Office on Dec. 6, 2004, and Japanese Patent Application No. 2004-376269, filed in the Japan Patent Office on Dec. 27, 2004, the contents being incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an electric fan system for a vehicle which uses an electric fan to generate cooling air. [0004] 2. Description of the Related Art [0005] In the past, as an electric fan system for a vehicle, there has been one which used an electric fan to circulate cooling air to a radiator for cooling engine cooling water and a condenser for vehicle air-conditioning so as cool the radiator and condenser. [0006] In general, in a taxi, bus, or other vehicle with a high frequency of use of the electric fan, a sufficient fan capacity, rectification of the d...

AI Technical Summary

Benefits of technology

[0016] A first object of the present invention is to provide an electric fan system for a vehicle enabling an extension of the lifetime while reducing the unevenness of the distribution of the flow rate.

[0017] A second object of the present invention is to provide an electric fan system for a vehicle designed to enable cooling of not only the radiator and condenser, but also other vehicle-mounted parts while extending the lifetime.

Problems solved by technology

However, in this case, by employing an electric motor with a large rated capacity, there is a possibility of inviting not only an increase in cost, but also an increase in weight.

Further, in an electric motor for an electric fan, it is known to employ a brushless motor so as to extend the lifetime of the electric motor, but when the dimension of the radiator in the vehicle width direction (left-right direction of vehicle) is larger than the dimension of the rotor of the electric fan in the vehicle width direction, with just a single electric fan, the distribution of air blown to the radiator would deteriorate and parts of the radiator where cooling air is not blown would end up arising thereby inviting a drop in the cooling efficiency of the radiator and in turn deterioration of the fuel economy.

As opposed to this, by employing two or more electric fans using brushless motors, it would become possible to rectify the distribution of blown air to the radiator and send sufficient cooling air to the radiator, but the control circuit for controlling the brushless motors would become complicated in configuration and a further increase in cost would be invited.

However, in the invention of the prior application, when the temperature of the cooling water is less than the predetermined temperature, the brush motor stops operating, but during this time the distribution of the flow rate in the vehicle width direction of the radiator becomes uneven.

In the above electric fan system for a vehicle using a brushless motor and brush motor, however, no consideration was given to cooling these other vehicle-mounted parts.

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