| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve engine fuel economy by promoting warm-up of an engine while suppressing the boiling of a coolant section in a cooling required section in the exhaust port periphery of a cylinder of a cylinder head in regard to a cooling device for an engine. Ž<P>SOLUTION: A nozzle passage 22 directed at the cooling required part of the exhaust port 12b periphery and communicated with a water jacket 14 is formed in the cylinder head 12. A sub-passage 18 branched off from between a cooling water outlet of the water jacket 14 of the cylinder head 12 and a radiator 15 in a main circuit and communicated with the nozzle passage 22 is provided in a cooling water circuit. During engine warm-up, by an ECU 23, an opening and closing valve 20 is operated such that a communicating state of cooling water between the radiator 15 in the main circuit and a cooling water inlet of an engine body 10 becomes a communication stopped state, and an electric pump 19 is operated such that a communicating state of cooling water in the sub-passage 18 sequentially becomes a communication stopped state, a first communicating state, and a second communicating state. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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