Patent attributes
An engine valve operating system is provided that includes a variable valve lift mechanism in which, when there is a possibility that the rotational speed of the engine might increase beyond an allowed rotational speed due to a downshift error in a manual transmission, etc., the amount of valve lift is decreased without changing the opening angle of the valve (19). By so doing, the curvature at the top of the curve of lift of the valve (19) is reduced, the inertial force applied to the valve (19) is reduced, and improper movement of the valve (19) can be prevented. Moreover, it is possible to prevent any increase in the intake air volume due to a decrease in the amount of lift of the valve (19), and prevent the effectiveness of engine braking from being degraded, thus enabling the rotational speed of the engine to be decreased and thereby preventing improper movement of the valve (19) from being promoted.
