Engine cooling system for vehicle

Abstract

An engine cooling system for a vehicle may include a cooling unit that circulates coolant through a cooling line connecting a water jacket, a water pump, and a radiator of an engine to cool the engine, and a sub-cooling unit that selectively circulates coolant through a sub-cooling line connecting the engine with a refrigerator so as to cool the engine.

What is claimed is: 
     
         1 . An engine cooling system for a vehicle, comprising:
 a cooling unit that circulates coolant through a cooling line connecting a water jacket, a water pump, and a radiator of an engine to cool the engine; and   a sub-cooling unit that selectively circulates coolant through a sub-cooling line connecting the engine with a refrigerator so as to cool the engine.   
     
     
         2 . The engine cooling system for the vehicle of  claim 1 ,
 wherein the refrigerator is disposed outside the engine, and   wherein the sub-cooling line includes:
 a first line that is diverged from the cooling line that connects the water pump with the engine and connected to the refrigerator to supply the refrigerator with coolant; and 
 a second line connecting the refrigerator and a sub-water jacket of the engine to supply the sub-water jacket with the coolant passing through the refrigerator. 
   
     
     
         3 . The engine cooling system for the vehicle of  claim 2 , wherein a valve is mounted in the second line between the refrigerator and the sub-water jacket. 
     
     
         4 . The engine cooling system for the vehicle of  claim 3 , wherein the valve opens the sub-cooling line to supply the sub-water jacket with the coolant that is cooled by the refrigerator when the engine is in a speed condition or a load condition. 
     
     
         5 . The engine cooling system for the vehicle of  claim 2 , wherein the sub-water jacket includes:
 a first connection passage that is formed at both lateral sides in a length direction of a cylinder head and connected to the second line of the sub-cooling line; and   at least a second connection passage that is connected to the first connection passage and is respectively formed corresponding to a combustion chamber.   
     
     
         6 . The engine cooling system for the vehicle of  claim 5 , wherein one end side of the second connection passage is connected to the first connection passage and the other end side thereof is formed toward an inner side of the cylinder head, and the second connection passage is formed vertically with regard to the first connection passage. 
     
     
         7 . The engine cooling system for the vehicle of  claim 2 , wherein the sub-water jacket includes:
 a first connection passage that is formed at both lateral sides in a length direction of a cylinder head and connected to the second line of the sub-cooling line; and   at least a second connection passage that is connected to the first connection passage and is respectively formed between combustion chambers.   
     
     
         8 . The engine cooling system for the vehicle of  claim 7 , wherein one end side of the second connection passage is connected to the first connection passage and the other end side thereof is formed toward an inner side of the cylinder head, and the second connection passage is formed vertically with regard to the first connection passage.