| 摘要 |
PROBLEM TO BE SOLVED: To accurately control valve opening/closing timing by minimizing a drop in oil pressure supplied to a VVT mechanism. SOLUTION: A first OCV 410 in a hydraulic circuit 400 for supplying oil pressure to a VVT mechanism supplies oil pressure in an oil passage 404 to an advancing chamber of the VVT mechanism in an advance region 412 and to a retarding chamber of the VVT mechanism in a retarding region 414, and shuts off the VVT mechanism 126 and oil passage 404 in a shut-off region 416. A second OCV 420 supplies oil pressure in the oil passage 404 to an advancing chamber 132 in an advancing region 422 and to a retarding chamber 134 in a retarding region 424, and includes no shut-off region in which the VVT mechanism 126 and oil passage 404 are shut off. Either of the first OCV 410 or second OCV 420 is selected in accordance with oil pressure in the oil passage 404 and engine rotation speed to control oil pressure supplied to the VVT mechanism 126. COPYRIGHT: (C)2008,JPO&INPIT
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