Engine fan control method and apparatus

Abstract

A thermal control system for an engine and/or peripheral components is disclosed wherein a fan may be actively coupled and decoupled from an engine's shaft based on a sensed parameter such as engine temperature, alternator temperature and/or supply fuel temperature. In one embodiment, the temperature is sensed at or near the engine thermostat or peripheral component and a controller controls an electromagnetic clutch to cause the fan to engage and disengage a shaft of the engine.

1 . A thermal control device for engines and engine components, comprising:
 a fan positioned to cool an engine and/or peripheral components;   a clutch disposed between the fan and the engine, the clutch is coupled to the fan and a shaft of the engine;   a sensor adapted to sense a parameter of the engine and/or one or more of the peripheral components; and   a controller adapted to receive the sensed parameter from the sensor and send a signal to the clutch to cause the clutch to either engage or disengage the fan with the shaft.   
   
   
       2 . The thermal control device of  claim 1 , wherein the sensed parameter is engine temperature and wherein the sensor is coupled to a thermostat of the engine and adapted to sense the temperature of the engine coolant. 
   
   
       3 . The thermal control device of  claim 1 , wherein the sensed parameter is thermostat position, and wherein the sensor is coupled to a thermostat of the engine and adapted to sense whether the thermostat is open or closed. 
   
   
       4 . The thermal control device of  claim 1 , wherein the sensor is coupled to an alternator and the sensed parameter is an alternator temperature. 
   
   
       5 . The thermal control device of  claim 1 , wherein the sensor is coupled to a fuel supply, and the sensed parameter is supply fuel temperature. 
   
   
       6 . The thermal control device of  claim 1 , wherein the sensed parameter is ambient temperature or humidity. 
   
   
       7 . The thermal control device of  claim 1 , further comprising a signal source coupled to the controller and the clutch, and wherein the controller is adapted to control when the signal source sends a signal to the clutch to control the coupling and decoupling of the fan to the shaft. 
   
   
       8 . The thermal control device of  claim 1 , wherein the clutch includes:
 a rotor coupled to the shaft and adapted to rotate with the shaft;   an armature proximally disposed to the rotor and adapted to rotate relative to the rotor and wherein the fan is coupled to and rotates with the armature; and   an electromagnet disposed on the rotor and/or armature, the electromagnet adapted to receive the signal from the controller to magnetize and de-magnetize the rotor and/or armature.   
   
   
       9 . The thermal control device of  claim 8 , further comprising a biasing element adapted to urge the armature and the rotor to be spaced apart relative to each other. 
   
   
       10 . The thermal control device of  claim 9 , wherein the biasing element is a spring or a magnetic field. 
   
   
       11 . A method of thermally controlling the temperature of an engine or peripheral component, comprising:
 sensing a parameter of the engine and/or peripheral component;   sending a signal representative of the parameter to a controller;   based on a predetermined parameter threshold, effecting a control signal on a fan clutch; and   selectively coupling and decoupling a fan to an engine shaft based on the effected control signal.   
   
   
       12 . The method of  claim 11 , further comprising providing an electromagnetic fan clutch to control the selectively coupling and decoupling of the fan to the engine shaft. 
   
   
       13 . The method of  claim 11 , wherein the effecting a control signal includes sending a voltage or current to the fan clutch. 
   
   
       14 . The method of  claim 11 , further comprising setting the predetermined parameter threshold based on the atmospheric conditions. 
   
   
       15 . The method of  claim 11 , wherein the sensing the parameter includes sensing the temperature of an engine coolant at an engine thermostat. 
   
   
       16 . The method of  claim 11 , wherein the sensing the parameter includes sensing the temperature of an alternator. 
   
   
       17 . The method of  claim 11 , wherein the sensing the parameter includes sensing the temperature of a supply fuel. 
   
   
       18 . A method of thermally controlling the temperature of an engine or peripheral components, comprising:
 providing a controller coupled to a fan clutch;   setting a desired time interval for which to have the clutch couple a fan to an engine shaft;   based on a set time interval, effecting a control signal on a fan clutch; and   selectively coupling and decoupling a fan to an engine shaft based on the effected control signal.