| 摘要 |
PROBLEM TO BE SOLVED: To provide a controller for a variable flow rate type water pump capable of securely suppressing cavitation in a high rotation region by ensuring sufficient flow rate of cooling water in a low rotation high load region to realize satisfactory cooling performance. SOLUTION: A suction side and a discharge side of the water pump are mutually communicated by a reflux passage provided with an opening and closing valve. When engine rotation speed Ne is less than switching point Nec set in the vicinity of cavitation occurrence rotation speed, the opening and closing valve is closed to ensure sufficient cooling water flow rate. When the engine rotation speed Ne is above the switching point Nec, the opening and closing valve is opened to reduce pump efficiency by circulation of cooling water in order to suppress cavitation. COPYRIGHT: (C)2004,JPO&NCIPI
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