Variable lift valve mechanism of an engine, and motorcycle engine

Abstract

The present invention discloses a variable lift valve mechanism of an engine, comprising a cam assembly, a valve rocker arm, a high-lift rocker arm, and a low-lift rocker arm, wherein the valve rocker arm is configured with a movable linkage pin; wherein the low-lift rocker arm drives the valve rocker arm to pivot when the linkage pin retracts from underneath the high-lift rocker arm, and the high-lift rocker arm experiences lost motion; when the linkage pin enters underneath the high-lift rocker arm, the high-lift rocker arm presses against the linkage pin and drives the valve rocker arm to pivot, and the low-lift rocker arm experiences lost motion. Compared to the prior art, in the present invention, during high-speed operating conditions, the rotational inertia applied to the valve spring is reduced, thereby reducing the valve spring design force and the power consumption of the variable valve lift rocker arms, so as to largely improve engine performance. The present invention further discloses a motorcycle engine comprising the foresaid variable lift valve mechanism.