| 摘要 |
PROBLEM TO BE SOLVED: To enhance the control responsiveness of a valve timing variable mechanism to prevent unstable burning due to considerable overlap of valve timings, and thereby ensure the stability of engine-revolution. SOLUTION: The variable valve timing device is provided with oil pressure control members 31, 32, 33 for controlling the oil pressure of hydraulic fluid of a valve timing variable mechanism 15. The oil pressure path between the valve timing variable mechanism and the oil pressure control members is divided into a spark-advance side oil path 63, 69 and a spark delay side oil path 65, 71, and circular grooves 70, 72 forming a part of both the oil paths are formed on the same camshaft bearing part 13. In relation to the lengths of the oil pressure paths, namely the spark advance side oil path 63, 69 from the pressure control members 31, 32, 33 up to both the circular grooves 70, 72 of the camshaft bearing part 13, and the spark delay side oil path 65, 71, the length of the oil pressure path 65, 71 by which overlap of valve timings of intake- and exhaust valves is reduced, is set shorter than the length of the oil pressure path 63, 69 by which overlap of valve timings of intake- and exhaust valves becomes larger.
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