Cooling device for engine

Abstract

A cooling device for engine includes: an engine having a cylinder block, a cylinder head and a gasket, the gasket being provided between the cylinder block and the cylinder head and having a high thermal conductivity member allowing heat transfer between an upper part of a cylinder and the cylinder head with a heat transfer rate higher than the other part, a partial W/J being provided around the high thermal conductivity member; and an ECU performing a control for changing flow condition of cooling medium flowing in the partial W/J, according to combustion engine operation condition.

1 . A cooling device for engine comprising:
 an engine having a cylinder block, a cylinder head, and a gasket, the gasket being provided between the cylinder block and the cylinder head and having a heat transfer allowing portion allowing heat transfer between an upper part of a cylinder of the cylinder block and the cylinder head with a heat transfer rate higher than the other part, a cooling medium pathway being provided around the heat transfer allowing portion in the cylinder head; and   a control portion performing a control for changing flow condition of cooling medium flowing in the cooling medium pathway, according to combustion engine operation condition.   
     
     
         2 . The cooling device for engine as claimed in  claim 1 , wherein the control portion performs a control for promoting heat transfer from the upper part of the cylinder to the cylinder head via the heat transfer allowing portion by changing the flow condition of the cooling medium flowing in the cooling medium pathway when the combustion engine operation condition is at least low rotation frequency and high load of a condition of low rotation frequency and high load condition and a condition of high rotation frequency and high load condition. 
     
     
         3 . The cooling device for engine as claimed in  claim 1  or  2 , wherein the heat transfer allowing portion is provided so as to surround a part of the gasket facing with the cylinder head and positioned on the side of a combustion chamber of the engine with an L-shape cross section. 
     
     
         4 . The cooling device for engine as claimed in any of  claims 1  to  3 , wherein the heat transfer allowing portion and the gasket are structured with different members. 
     
     
         5 . The cooling device for engine as claimed in any of  claims 1  to  4 , wherein a convex-concave portion capable of generating flow peeling of cooling medium according to flow speed within a range of maximum flow speed of the cooling medium is provided on a wall surface of a pathway on the side of the cylinder block in the cooling medium pathway. 
     
     
         6 . The cooling device for engine as claimed in any of  claims 1  to  5 , further comprising a cooling capacity adjusting portion that is capable of restraining cooling capacity of the cylinder head without restraining cooling capacity of the cylinder block,
 wherein the control portion performs a control for restraining the cooling capacity of the cylinder head by controlling the cooling capacity adjusting portion.