Variable input speed to water pump

Abstract

A variable ratio drive belt system is used to drive the water pump. The variable ratio drive belt system comprises a variable pitch water pump pulley, or driven pulley, a variable pitch crankshaft pulley, or driver pulley, and a drive belt that is coupled between a water pump and an engine crankshaft. By increasing and decreasing the size of the variable pitch water pump pulley and increasing the size of the variable pitch crankshaft pulley as a function of engine speed, the water pump speed can be increased at low engine speed to provide improved coolant flow and decreased at higher engine speeds to prevent pump cavitation.

1 . A cooling system comprising: 
 an engine crankshaft;    a water pump having at least one impeller; and    a variable drive ratio belt system coupled between said engine crankshaft and said water pump, said variable drive ratio belt system having a variable pitch crankshaft pulley coupled to said engine crankshaft, a variable pitch water pump pulley coupled to said water pump, and a drive belt coupled to said variable pitch crankshaft pulley and said variable pitch water pump pulley.    
   
   
       2 . The cooling system of  claim 1 , wherein said variable pitch crankshaft pulley has a first crankshaft pulley half and a second crankshaft pulley half held together at a first distance by a crankshaft pulley spring; and 
 wherein said variable pitch water pump pulley has a first water pump pulley half and a second water pump pulley half held apart at a second distance by a water pump pulley spring.    
   
   
       3 . The cooling system of  claim 2 , wherein said first crankshaft pulley half has a first inner sloping surface and wherein said second crankshaft pulley half has a second inner sloping surface such that said drive belt rests upon a portion of said first inner sloping surface and said second inner sloping surface defined by said first distance; and 
 wherein said first water pump pulley half has a third inner sloping surface and wherein said second water pump pulley half has a fourth inner sloping surface, wherein said drive belt rests upon a portion of said third inner sloping surface and said fourth inner sloping surface defined by said second distance.    
   
   
       4 . The cooling system of  claim 3 , wherein said first distance increases as a function of an increased engine rotational speed and decreases as a function of a decreased engine rotational speed.  
   
   
       5 . The cooling system of  claim 4 , wherein said second distance decreases in response to said first distance increasing; and 
 wherein said second distance increases in response to said first distance decreasing.    
   
   
       6 . The cooling system of  claim 3 , wherein said second distance decreases as a function of increased drive belt rotational speed and increases as a function of decreased drive belt rotational speed.  
   
   
       7 . The cooling system of  claim 6 , wherein the increase of said second distance decreases a water pump belt diameter of said drive belt.  
   
   
       8 . The cooling system of  claim 6 , wherein the decrease of said second distance increases a water pump belt diameter of said drive belt.  
   
   
       9 . A method for preventing pump cavitation of a belt driven water pump having a plurality of impellers, said impellers rotating to pump coolant to an engine block, the method comprising: 
 coupling a variable pitch crankshaft pulley to an engine crankshaft,    coupling a variable pitch water pump pulley to the water pump; and    coupling a drive belt under tension to said variable pitch crankshaft pulley and to said variable pitch water pump pulley.    
   
   
       10 . The method of  claim 9 , wherein coupling a drive belt comprises: 
 coupling a drive belt to a variable pitch crankshaft pulley such that said drive belt is coupled to a first inner sloping surface of each of a pair of crankshaft pulley halves separated by a first distance; and    coupling said drive belt at a desired tension to a variable pitch water pump pulley such that said drive belt is coupled a second inner sloping surface of a pair of water pump pulley halves separated by a second distance.    
   
   
       11 . The method of  claim 10 , wherein each of said crankshaft pulley halves is maintained together at said first distance by a crankshaft spring.  
   
   
       12 . The method of  claim 10 , wherein each of said water pump pulley halves is forced apart at said second distance by a water pump pulley spring.  
   
   
       13 . The method of  claim 10 , wherein each of said crankshaft pulley halves is maintained together at said first distance by a crankshaft spring; and 
 wherein each of said water pump pulley halves is forced apart at said second distance by a water pump pulley spring.    
   
   
       14 . The method of  claim 13 , wherein an increase in the rotational speed of said drive belt causes said first distance to increase and said second distance to decrease while maintaining said desired tension.  
   
   
       15 . A variable drive ratio belt system for use in a cooling system comprising: 
 a variable pitch crankshaft pulley,    a variable pitch water pump pulley, and    a drive belt coupled to said variable pitch crankshaft pulley.    
   
   
       16 . The variable drive ratio belt system of  claim 15 , wherein said variable pitch crankshaft pulley has a first crankshaft pulley half and a second crankshaft pulley half held together at a first distance by a crankshaft pulley spring; and 
 wherein said variable pitch water pump pulley has a first water pump pulley half and a second water pump pulley half held apart at a second distance by a water pump pulley spring.    
   
   
       17 . The variable drive ratio belt system of  claim 16 , wherein said first crankshaft pulley half has a first inner sloping surface and wherein said second crankshaft pulley half has a second inner sloping surface such that said drive belt rests upon a portion of said first inner sloping surface and said second inner sloping surface defined by said first distance; and 
 wherein said first water pump pulley half has an third inner sloping surface and wherein said second water pump pulley half has a fourth inner sloping surface, wherein said drive belt rests upon a portion of said third inner sloping surface and said fourth inner sloping surface defined by said second distance.    
   
   
       18 . The variable drive ratio belt system of  claim 16 , wherein said first crankshaft pulley half has an first inner sloping surface and wherein said second crankshaft pulley half has a second inner sloping surface such that said drive belt rests upon a portion of said first inner sloping surface and said second inner sloping surface defined by said first distance  
   
   
       19 . The variable drive ratio belt system of  claim 16 , wherein said first water pump pulley half has an third inner sloping surface and wherein said second water pump pulley half has a fourth inner sloping surface, wherein said drive belt rests upon a portion of said third inner sloping surface and said fourth inner sloping surface defined by said second distance.  
   
   
       20 . The variable drive ratio belt system of  claim 16 , wherein said second distance decreases as a function of an increased drive belt rotational speed to decrease a drive belt diameter of said water pump pulley; and 
 wherein said second distance increases as a function of decreased drive belt rotational speed to increase a drive belt diameter of said water pump pulley.