| 摘要 |
PROBLEM TO BE SOLVED: To improve operational follow-up performance of an engine valve to a rocking cam of a variable control device, to prevent looseness of a link mechanism, and to improve operational responsiveness. SOLUTION: This variable valve system has a driving shaft 13 for arranging a driving cam 15 on the outer periphery, the rocking cam 17 for operating opening-closing by sliding on an upper end part of a suction valve 12, inner-outer double valve springs 20 and 21 for energizing the suction valve in the rocking cam direction, a rocker arm 23 having one end part linked to the driving cam via a link arm 24, and the other end part linked to the rocking cam via a link member 25, and a control mechanism for varying a valve lifting amount of the suction valve by the rocking cam by changing an attitude of the rocker arm according to an engine operation state. A rate of change of a spring load of both valve springs is set so as to become a nonlinear characteristic such as spring reaction to the rocking cam becomes large as a valve opening quantity of the engine valve increases when controlling a high valve lifting amount of the engine valve. COPYRIGHT: (C)2003,JPO
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