Cooling system for vehicle

Claim 1

A cooling system for a vehicle configured so as to vary draft volume to the radiator through which engine cooling medium is circulated in accordance with operating conditions of the engine, comprising: a plurality of motor fans for air cooling the radiator, sensor means for sensing the temperature of the cooling medium at both the inlet and outlet sides of the radiator, and an operational mode control means, responsive to the outputs of said sensor means, for selectively controlling a plurality of operational modes programmed to selectively supply power to each of said plurality of motor-fans in order to optimize draft volume to the radiator, thereby enabling fine adjustment of draft volume to the radiator in order to effect a desired cooling of the engine; wherein said operational modes include a parallel drive mode for parallely providing power to each of said plurality of motor-fans, a serial drive mode for serially providing power thereto, a parallel drive mode for providing power to less than all of said plurality of motor-fans, and an OFF mode for disconnecting all said plurality of motor-fans from the power source; and wherein said operational mode control means selectively controls the control mode of the system according to the Table ______________________________________ Conditions 1 2 3 4 5 6 7 8 ______________________________________ air OFF o o o o conditioner switch ON o o o o Temper- up to o o o o ature of T.sub.1 water from above o o o o radiator T.sub.1 Temper- up to o o o o ature of T.sub.2 water into above o o o o radiator T.sub.2 driving OFF LO MI HI LO LO HI HI mode of motor- fans ______________________________________ wherein T 2 is greater than T 1 , HI indicates a parallel drive mode, MI indicates a partial drive mode, LO indicates a serial drive mode and OFF indicates an OFF mode.