Patent ID: 7182048

Claim:
An internal combustion engine cooling system comprising: a radiator that receives cooling water from an internal combustion engine, cools the cooling water and returns cooled cooling water into the internal combustion engine; a coolant passage connecting the internal combustion engine and the radiator, and including an inlet passage through which the cooling water flows from the internal combustion engine into the radiator, and an outlet passage through which the cooling water flows from the radiator into the internal combustion engine; a bypass passage connecting the inlet passage and the outlet passage to make the cooling water discharged from the internal combustion engine bypass the radiator; a flow control valve placed at a junction of the outlet passage and the bypass passage to control radiator flow rate at which the cooling water flows through the radiator and bypass flow rate at which the cooling water flows through the bypass passage; a water pump placed in the inlet or the outlet passage to circulate the cooling water through the internal combustion engine and the radiator; a desired coolant temperature setting means for setting a normal desired coolant temperature of the cooling water flowing through the outlet passage; and a coolant temperature control means for controlling temperature of the cooling water flowing through the outlet passage on the basis of the desired coolant temperature set by the desired coolant temperature setting means, wherein the desired coolant temperature setting means changes the desired coolant temperature according to operating condition of the internal combustion engine, traveling condition of a vehicle mounted with the internal combustion engine, and ambient condition, and wherein the desired coolant temperature setting means sets a desired coolant temperature for an uphill traveling mode differently from the normal desired coolant temperature when the vehicle is traveling in the uphill traveling mode, and sets a desired coolant temperature for a downhill traveling mode differently from the normal desired coolant temperature when the vehicle is traveling in the downhill traveling mode.