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 V 1 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 V 2 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 ( 40 a ) 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 ).

1 . An electric fan system for a vehicle which circulates cooling air to a heat exchange unit provided with a radiator for cooling cooling water circulating inside a water-cooled engine for vehicle operation and a condenser for cooling a coolant circulating inside a refrigeration cycle apparatus, 
 the system comprising:    a brushless motor driven by a first drive voltage,    a first electric fan circulating cooling air to the heat exchange unit by the brushless motor,    a brush motor driven by a second drive voltage,    a second electric fan circulating cooling air to the heat exchange unit by the brush motor, and    a control device supplying the brushless motor with the first drive voltage so that the first drive voltage monotonously increases up to a first maximum drive voltage in accordance with a rise in temperature of the cooling water and for supplying the brush motor with the second drive voltage so that the second drive voltage monotonously increases up to a second maximum drive voltage in accordance with a rise in temperature of the cooling water and becomes a voltage lower than the first drive voltage based on the detection output from a temperature sensor for detecting the temperature of the cooling water.    
   
   
       2 . An electric fan system for a vehicle as set forth in  claim 1 , wherein when the temperature of the cooling water is a temperature of a temperature threshold value or more, the first and second maximum drive voltages are set to become constant values.  
   
   
       3 . An electric fan system for a vehicle which circulates cooling air to a heat exchange unit provided with a radiator for cooling cooling water circulating inside a water-cooled engine for vehicle operation and a condenser for cooling a coolant circulating inside a refrigeration cycle apparatus, 
 the system comprising:    a brushless motor driven by a first drive voltage,    a first electric fan circulating cooling air to the heat exchange unit by the brushless motor,    a brush motor driven by a second drive voltage,    a second electric fan for circulating cooling air to the heat exchange unit by the brush motor, and    a control device for supplying the brushless motor with the first drive voltage so that the first drive voltage monotonously increases up to a first maximum drive voltage in accordance with a rise in pressure of the coolant and for supplying the brush motor with the second drive voltage so that the second drive voltage monotonously increases up to a second maximum drive voltage in accordance with a rise in pressure of the coolant and becomes a voltage lower than the first drive voltage based on the detection output from a pressure sensor for detecting the pressure of the coolant in the condenser.    
   
   
       4 . An electric fan system for a vehicle as set forth in  claim 3 , wherein when the pressure of the coolant is a pressure of a pressure threshold value or more, the first and second maximum drive voltages are set to become constant values.  
   
   
       5 . An electric fan system for a vehicle as set forth in  claim 1 , wherein both the first and second electric fans are axial flow fans and the fan diameters are substantially equal.  
   
   
       6 . An electric fan system for a vehicle which circulates cooling air to a heat exchange unit provided with a radiator for cooling cooling water circulating inside a water-cooled engine for vehicle operation and a condenser for cooling a coolant circulating inside a refrigeration cycle apparatus, 
 the system comprising:    a first electric fan circulating cooling air to the radiator and condenser by operation of a brushless motor,    a second electric fan for circulating cooling air to the radiator and condenser by a brush motor, and    a control means for operating the first electric fan preferentially over the second electric fan based on a state of either the cooling water and the coolant,    the first electric fan being designed to cool other vehicle-mounted parts than the radiator and condenser by cooling air.    
   
   
       7 . An electric fan system for a vehicle as set forth in  claim 6 , wherein the control means determines the flow rate of cooling air by the first electric fan based on both the state of one of the cooling water and the coolant and the temperature of the other vehicle-mounted parts.  
   
   
       8 . An electric fan system for a vehicle as set forth in  claim 6 , wherein the first electric fan is designed to blow air toward locations different from the locations where the other vehicle-mounted parts are arranged.