| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve gear of an engine capable of raising the engine speed limit while improving durability. SOLUTION: In this valve gear, when maximum valve lift on the exhaust side and intake side is Lexo, Lino, respectively, Lexo<Lino. Also, with regard to at least the intake side, when valve lift Y is expressed as the function Y=f (θ) of the rotation angleθof the camshaft, the absolute value of the acceleration coefficient Y"=d<2> f (θ)/dθ<2> near maximum valve lift becomes smaller than the absolute value of the acceleration coefficient in the adjacent valve lift regions on the advance side and the retard side. Alternatively, a camshaft is provided having an exhaust cam profile and intake cam profile, set such that the curvature radius near maximum valve lift becomes larger than the curvature radius at the adjacent valve lift region on the advance side and the retard side.
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