Engine cooling system with coolant shunt

Abstract

A cooling system for a liquid cooled internal combustion engine having an internal water jacket, a water pump having an outlet connected to an inlet of the water jacket, a thermostat housing including a thermostat and having an inlet connected with an outlet of the water jacket, a heat exchanger connected between an outlet of the thermostat housing and an inlet of the water pump for cooling the liquid in the cooling system, includes a coolant shunt extending from the water pump outlet to the inlet of the thermostat housing whereby when the thermostat is open, coolant flow through the heat exchanger is greater than coolant flow thorough the engine so that heat exchanger cooling is increased and parasitic losses across the water pump are minimized.

What is claimed is:  
     
         1 . A cooling system for a liquid cooled internal combustion engine including an internal water jacket, a water pump having an outlet connected to an inlet of the water jacket, a thermostat housing including a thermostat and having an inlet connected with an outlet of the water jacket, a heat exchanger connected between an outlet of the thermostat housing and an inlet of the water pump for cooling the liquid in the cooling system, said system comprising: 
 a coolant shunt extending from the water pump outlet to the inlet of said thermostat housing, whereby when the thermostat is open, coolant flow through said heat exchanger is greater than coolant flow through the engine so that heat exchanger cooling is increased and parasitic losses across said water pump are minimized.    
     
     
         2 . The cooling system of  claim 1  including a bypass extending from the thermostat housing inlet to said water pump inlet.  
     
     
         3 . The cooling system of  claim 1  wherein said thermostat controls flow through both heat exchanger and bypass.  
     
     
         4 . The cooling system of  claim 1  wherein said shunt bypasses about ⅓ of the liquid flow to the heat exchanger around the engine water jacket.  
     
     
         5 . A method of increasing coolant flow through the radiator in a cooling system for a liquid cooled internal combustion engine including an internal water jacket, a water pump having an outlet connected to an inlet of the water jacket, a thermostat housing including a thermostat and having an inlet connected with an outlet of the water jacket, the radiator connected between an outlet of the thermostat housing and an inlet of the water pump for cooling the liquid in the cooling system, the method comprising the steps of: 
 providing a coolant shunt that extends from the water pump outlet to the inlet of the thermostat housing, whereby when the thermostat is open, coolant flow through the radiator is greater than coolant flow through the engine so that heat exchanger cooling is increased and parasitic losses across the water pump are minimized.