| 摘要 |
PURPOSE:To improve the fuel efficiency at the start of engine by rising the temperature of engine cooling water to the steady temperature level by means of a heater. CONSTITUTION:A control relay 9 is excited by closing a heater switch 12 prior to starting of engine or by a timer signal 6 to be fed from a timer circuit 5 at a random time and a current is fed to a heater 7 so as to heat the cooling water 13 in a cooling system 1. When the temperature of cooling water measured by means of a water temperature sensor 2 and a water temperature detecting circuit 3 reaches to a steady temperature level, the heater control circuit 10 receives a detection signal 4 from the water temperature detecting circuit 3 so as to de-energize the control relay 9 thus stopping the driving of the heater 7. Consequently, the engine temperature necessary for achieving a stable operation of engine can be ensured in short time thereby the warming operation can be eliminated or shortened.
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