Cooling water temperature control apparatus for an internal combustion engine

Abstract

The present invention is intended to provide a technique which makes effective use of a phase transition temperature zone of cooling water by controlling a control valve for changing the temperature of the cooling water in an appropriate manner. The present invention resides in a cooling water temperature control apparatus for an internal combustion engine in which cooling water is caused to circulate, said cooling water having variable specific heat, said apparatus comprising: a received heat amount calculation unit configured to calculate an amount of received heat which is received by said cooling water, a control valve that is controlled to open and close according to a command so as to change a circulation route or an amount of circulation of said cooling water and to change the temperature of said cooling water, and a control unit configured to control said control valve based on the amount of received heat which is calculated by said received heat amount calculation unit.

1 .- 4 . (canceled) 
     
     
         5 . A cooling water temperature control apparatus for an internal combustion engine in which cooling water is caused to circulate, said cooling water having variable specific heat, said apparatus comprising:
 a received heat amount calculation unit configured to calculate an inlet received heat amount which is received by said cooling water at an inlet port from which said cooling water flows into the internal combustion engine;   a control valve that is controlled to open and close according to a command so as to change a circulation route or an amount of circulation of said cooling water and to change the temperature of said cooling water; and   a control unit configured to control said control valve in such a manner that said inlet received heat amount calculated by said received heat amount calculation unit comes near to a lower side starting value of received heat amount of a phase transition temperature zone in which said cooling water is in a state in which the specific heat thereof changes due to a phase transition of particles.   
     
     
         6 . The cooling water temperature control apparatus for an internal combustion engine as set forth in  claim 5 , wherein
 said received heat amount calculation unit calculates an outlet received heat amount which is received by said cooling water at an outlet port from which said cooling water flows out of the internal combustion engine; and   in cases where said outlet received heat amount calculated by said received heat amount calculation unit becomes a high amount of received heat in excess of an amount of received heat of said phase transition temperature zone, said control unit controls said control valve so that said outlet received heat amount is included in the range of the amount of received heat of said phase transition temperature zone.   
     
     
         7 . The cooling water temperature control apparatus for an internal combustion engine as set forth in  claim 5 , wherein
 in cases where said received heat amount calculation unit can not calculate the amount of received heat, said control valve is controlled in such a manner as to lower the temperature of said cooling water.   
     
     
         8 . The cooling water temperature control apparatus for an internal combustion engine as set forth in  claim 6 , wherein
 in cases where said received heat amount calculation unit can not calculate the amount of received heat, said control valve is controlled in such a manner as to lower the temperature of said cooling water.