Cooling system controller for internal combustion engines

A cooling system controller for internal combustion engines comprising:

• a first radiator and a second radiator,
• a first water jacket provided to a cylinder head,
• a second water jacket provided to a cylinder block,
• a first water pump and a second water pump, being provided respectively at the upperstream side of said first or second water jacket,
• a first and second conduits, connecting respectively an outlet port at the downstream side of said first or second water jacket to an inlet port of said first or second radiator,
• a first return passageway and a second return passageway, connecting respectively an outlet port of said first or second radiator to said first or second water pump,
• a first bypass passageway and a second bypass passageway, being branched respectively from said first or second conduit and communicating respectively with said first or second return passageway,
• a first mixing valve and a second mixing valve, being disposed respectively at the junction of said first or second bypass passageway and said first or second return passageway, to mix cooling water of the two passageways and return it to said first or second water pump respectively,
• a first motor fan and a second motor fan, to supply cooling water respectively to said first or second radiator,
• a first heater circuit and second heater circuit, being branched out respectively at the outlet port of the downstream side of said first or second water jacket,
• said first and second heater circuits being junctioned by a first selector valve at the upperstream of a heater radiator, being separated by a second selector valve at the downstream of said heater radiator, and returning respectively to a main water circuit at a position which is on the upperstream of said first or second water pump and on the downstream of said first or second mixing valve, and
• said first and second selector valves having the function to supply water of the higher temperature from either of said first and second water jackets to said heater radiator by the signals from a control unit which detects the temperature at the downstream side outlet ports of said first and second water jackets and compares them, and having the function to shut off both water flows.