| 摘要 |
PROBLEM TO BE SOLVED: To improve volumetric efficiency of intake air by rapidly changing the opening/closing timing of an intake air valve according to the change of an engine speed so as to omit the opening/closing timing in which sufficient intake air inertia cannot be obtained due to intake air interference in the specific engine speed range of an internal combustion engine. SOLUTION: In a variable valve system, an inconstant velocity coupling 13 is arranged between a camshaft 11 and a cam rope 12 arranged around the circumference of the camshaft 11. The inconstant velocity coupling 13 has a control disk 14 journaled to the camshaft 11 and an eccentric part 15 integrally arranged to the control disk 14, and first and second slider members 17, 18 are connected to an engaging disk 16 arranged to the eccentric part 15. Valve opening/closing timing is adjusted by preceding/delaying the cam rope 12 against the camshaft 11. In this case, the phase of the control disk 14 is set to beψ1 during a period from idling to an engine speed N1 , however, the phase is changed step by step when it exceeds N1 , so that volumetric efficiency of intake air is improved.
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