Apparatus and method for fan soft-start controller

Abstract

A system and method for controlling the operation of a vehicle radiator fan motor is provided. One embodiment receives one of a low-speed radiator fan control signal or a high-speed radiator fan control signal from an engine control module; provides a first soft start of the radiator fan motor in response to receiving the low-speed radiator fan control signal, wherein the first soft start is defined by a first increasing power ramp that starts at a zero-power level and ends at a low-speed power level; and provides a second soft start of the radiator fan motor in response to receiving the high-speed radiator fan control signal, wherein the second soft start is defined by a second increasing power ramp that starts at the zero-power level and ends at a high-speed power level.

1 . A method for controlling operation of a vehicle radiator fan motor that transports a cool ambient air over a radiator of a vehicle so that a cooled radiator fluid may be transported from the radiator of the vehicle into a combustion engine block to cool the combustion engine block, comprising:
 sensing a temperature of the combustion engine block of the vehicle using a sensor that detects the temperature of the combustion engine block;   communicating, from the sensor to a vehicle engine control module, temperature information, wherein the temperature information corresponds to the temperature of the combustion engine block;   communicating, from the vehicle engine control module to a radiator fan soft-start controller, one of a low-speed radiator fan control signal and a high-speed radiator fan control signal,
 wherein the low-speed radiator fan control signal is communicated from the vehicle engine control module in response to the temperature of the combustion engine block exceeding a first predefined threshold temperature, and 
 wherein the high-speed radiator fan control signal is communicated from the vehicle engine control module in response to the temperature of the combustion engine block exceeding a second predefined threshold temperature that is higher than the first predefined threshold temperature; 
   outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, a first soft start to the vehicle radiator fan motor in response to receiving the low-speed radiator fan control signal from the vehicle engine control,
 wherein the first soft start is defined by a first increasing power ramp that starts at a zero-power level and ends at a low-speed power level, 
 wherein the first soft start is defined by a first duration, and 
 wherein the low-speed power level operates the vehicle radiator fan motor at a predefined low speed to transport the cool ambient air over the radiator of the vehicle so that the cooled radiator fluid may be transported from the radiator of the vehicle into the combustion engine block to cool the combustion engine block; 
   outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, a second soft start to the vehicle radiator fan motor in response to receiving the high-speed radiator fan control signal from the vehicle engine control module,
 wherein the second soft start is defined by a second increasing power ramp that starts at the zero-power level and ends at a high-speed power level, 
 wherein the second soft start is defined by a second duration, and 
 wherein the high-speed power level operates the vehicle radiator fan motor at a predefined high speed that is faster than the predefined low speed to transport the cool ambient air over the radiator of the vehicle so that the cooled radiator fluid may be transported from the radiator of the vehicle into the combustion engine block to cool the combustion engine block; and 
   operating the vehicle radiator fan motor, in response to receiving one of the first soft start and the second soft start from the radiator fan soft-start controller, to transport the cool ambient air over the radiator of the vehicle to cool the radiator fluid that is transported from the radiator of the vehicle into the combustion engine block to cool the combustion engine block.   
     
     
         2 . The method of  claim 1 , wherein the first duration of the first soft start is the same as the second duration of the second soft start. 
     
     
         3 . The method of  claim 1 , wherein the first duration of the first soft start is less than the second duration of the second soft start. 
     
     
         4 . The method of  claim 1 , wherein the low-speed power level of the first soft start is equal to half of the high-speed power level of the second soft start. 
     
     
         5 . The method of  claim 4 , wherein the high-speed power level of the second soft start corresponds to an operating voltage of the vehicle in which the vehicle radiator fan motor resides. 
     
     
         6 . The method of  claim 1 , wherein outputting the first soft start comprises:
 generating a series of power pulses,   wherein each subsequent power pulse in the series of power pulses has an increasing duration greater than the previous power pulse,   wherein a first one of the series of voltage power pulses has a smallest duration of the series of power pulses and is generated by the radiator fan soft-start controller in response to receiving the low-speed radiator fan control signal from the vehicle engine control module, and   wherein a last one of the series of power pulses has a largest duration of the series of power pulses and is generated proximate to a conclusion of the first soft start.   
     
     
         7 . The method of  claim 6 , further comprising:
 outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, a continuing series of power pulses to the vehicle radiator fan motor after the conclusion of the first soft start,   wherein the continuing series of power pulses each have a duration that corresponds to the low-speed power level provided to the vehicle radiator fan motor   
     
     
         8 . The method of  claim 6 , further comprising:
 turning a pulse width modulation (PWM) power switch to an on state to begin each one of the series of power pulses, and   turning the PWM power switch to an off state to end each one of the series of power pulses.   
     
     
         9 . The method of  claim 6 , wherein the series of power pulses output during the first soft start is a first series of power pulses, and further comprising:
 generating a second series of power pulses after the conclusion of the first soft start,   wherein the second series of pulses have a same predefined duration, and   wherein each one of the second series of power pulses are separated from each other by the same predefined duration.   
     
     
         10 . The method of  claim 9 , further comprising:
 turning a pulse width modulation (PWM) power switch to an on state to begin each one of the second series of power pulses, and   turning the PWM power switch to an off state to end each one of the second series of power pulses.   
     
     
         11 . The method of  claim 9 , further comprising:
 detecting an end to the received low-speed radiator fan control signal; and   outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, a soft shutdown of the vehicle radiator fan motor in response to detecting the end of the low -speed radiator fan control signal,   wherein the soft shutdown is defined by a decreasing power ramp that starts at the low-speed power level and ends at the zero-power level, and   wherein the vehicle radiator fan motor receives no power at a conclusion of the soft shutdown.   
     
     
         12 . The method of  claim 11 , wherein outputting the soft shutdown comprises:
 generating a third series of power pulses of decreasing duration in response to detecting the end of the low-speed radiator fan control signal,   wherein a first one of the third series of power pulses has a largest duration of the third series of power pulses and is generated in response to detecting the end of the low-speed radiator fan control signal, and   wherein a last one of the third series of power pulses has a smallest duration of the third series of power pulses and is generated proximate to the conclusion of the soft shutdown.   
     
     
         13 . The method of  claim 1 , wherein outputting the second soft start comprises:
 generating a series of power pulses of increasing duration,   wherein a first one of the series of power pulses has a smallest duration of the series of power pulses and is generated in response to receiving the high-speed radiator fan control signal, and   wherein a last one of the series of power pulses has a largest duration of the series of power pulses and is generated proximate to a conclusion of the second soft start.   
     
     
         14 . The method of  claim 13 , further comprising:
 turning a pulse width modulation (PWM) power switch to an on state to begin each one of the series of power pulses, and   turning the PWM power switch to an off state to end each one of the series of power pulses.   
     
     
         15 . The method of  claim 13 , further comprising:
 outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, the high-speed power level to the vehicle radiator fan motor after the conclusion of the second soft start.   
     
     
         16 . The method of  claim 15 , further comprising:
 maintaining a pulse width modulation (PWM) power switch in an on state to provide the high-speed power level.   
     
     
         17 . The method of  claim 16 , further comprising:
 detecting an end to the received high-speed radiator fan control signal; and   outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, a soft shutdown of the vehicle radiator fan motor in response to detecting the end of the high-speed radiator fan control signal,
 wherein the soft shutdown is defined by a decreasing power ramp that starts at the high-speed power level and ends at the zero-power level, and 
 wherein the vehicle radiator fan motor receives no power at a conclusion of the soft shutdown. 
   
     
     
         18 . The method of  claim 17 , wherein the series of power pulses provided during the second soft start is a first series of power pulses, wherein outputting the soft shutdown comprises:
 generating a second series of power pulses of decreasing duration in response to detecting the end of the high-speed radiator fan control signal,   wherein a first one of the second series of power pulses has a largest duration of the second series of power pulses and is generated in response to detecting the end of the high-speed radiator fan control signal, and   wherein a last one of the second series of power pulses has a smallest duration of the second series of power pulses and is generated proximate to the conclusion of the soft shutdown.   
     
     
         19 . A method for controlling operation of a vehicle radiator fan motor that transports a cool ambient air over a radiator of a vehicle so that a cooled radiator fluid may be transported from the radiator of the vehicle into a combustion engine block to cool the combustion engine block, comprising:
 sensing a temperature of the combustion engine block of the vehicle using a sensor that detects the temperature of the combustion engine block;   communicating, from the sensor to a vehicle engine control module, temperature information, wherein the temperature information corresponds to the temperature of the combustion engine block;   communicating, from the vehicle engine control module to a radiator fan soft-start controller, a radiator fan control signal in response to the temperature of the combustion engine block exceeding a predefined threshold temperature;   receiving, at the radiator fan soft-start controller, the radiator fan control signal from the vehicle engine control module,   outputting, from the radiator fan soft-start controller to the vehicle radiator fan motor, a soft start to the vehicle radiator fan motor in response to receiving the radiator fan control signal,
 wherein the radiator fan control signal is communicated from the vehicle engine control module in response to the temperature of the combustion engine block exceeding a predefined threshold temperature, 
 wherein the soft start is defined by a first increasing power ramp that starts at a zero-power level and ends at an intended speed power level, 
 wherein the soft start is defined by a first duration, and 
 wherein the intended speed power level operates the vehicle radiator fan motor at a predefined intended speed; and 
   operating the vehicle radiator fan motor, in response to receiving the soft start from the radiator fan soft-start controller, to transport the cool ambient air over the radiator of the vehicle to cool the radiator fluid that is transported from the radiator of the vehicle into the combustion engine block to cool the combustion engine block.   
     
     
         20 . The method of  claim 19 , wherein outputting the soft start comprises:
 generating a series of power pulses,   wherein each subsequent power pulse in the series of power pulses has an increasing duration greater than the previous power pulse,   wherein a first one of the series of voltage power pulses has a smallest duration of the series of power pulses and is generated in response to receiving the radiator fan control signal, and   wherein a last one of the series of power pulses has a largest duration of the series of power pulses and is generated proximate to a conclusion of the soft start.