| 摘要 |
PROBLEM TO BE SOLVED: To prevent wrong control due to fluctuation of engine water temperature by reducing delayed operation of a thermostat due to intermittent circulation of cooling water and improve fuel economy, emission and the like by accelerating warming up as quick as possible in a water cooled engine intermittently circulating cooling water during warming up. SOLUTION: An electric pump 9 is stopped for a predetermined period of time after cold start to stop circulation of cooling water in water jackets 4, 5. After that, the pump is operated in a short pulse control mode to intermittently circulate cooling water. Consequently, whole cooling water is slightly stirred while reducing heat radiation quantity to inhibit local temperature rise. When detection value th of cooling water temperature gets to valve open start temperature th1 of the thermostat 13, operation of the electric pump 9 is changed over to a long pulse control mode to increase circulation quantity of cooling water and reduce temperature difference of cooling water from the water jackets 4, 5 to a periphery of the thermostat 13. COPYRIGHT: (C)2007,JPO&INPIT
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