Abstract: Valve lift and duration may be varied by moving the pivot of a rocker arm or finger follower, and simultaneously altering the valve clearance during engine operation. The phase of the valve event may also be varied by moving the rocker arm lengthwise at the same time that the pivot is moved. This is accomplished by using a different diameter for the toothed cog tracking across a stationary rack as for the toothed cog that engages the rocker arm or finger follower. Controlled variation of lift, duration and phase may be achieve solely with a moving pivot.

Abstract: Variable valve lift in an engine is achieved by varying the location of the pivot of the rocker arm or finger follower as stated in an earlier patent application. The path of contact between the rocker arm or finger follower and the pivot may be circular or non-circular. The relationship between adjustment clearance and pivot shaft position yields controlled variation of phase and duration. At full lift the clearance would be within usual limits, while at partial lift reduced contact velocities allow greater clearance without increasing idle noise, and thus opening of valves may be delayed, and closing advanced. Deactivation of valves can occur with reduced lift and a suitably increased adjustment clearance, while maintaining adequately low contact velocities. With individual control of valves, one or more cylinders may be deactivated, or by varying lift independently on multi-valve engines, mixing of incoming gases may be enhanced.

Abstract: Variable valve lift in an engine is achieved by varying the location of the pivot of the rocker arm or finger follower. The pivot shaft and rocker arm or finger follower have engaging teeth that mate. The pivot shaft rolls across a stationary rack of teeth to change the ratio of valve lift to cam lift, while, for a given position of the pivot shaft, preventing the pivot shaft from rotating. The pivot shaft rides in a bearing block whose movement is constrained by a bearing guide of the same shape as the stationary rack. The shape of the toothed rack on the rocker arm or finger follower is part of a circular cylinder whose radius is determined by the position and angles of the cam and valve. The shape of the stationary rack and bearing guide may vary from that of the rocker arm to allow for altered adjustment clearance with different valve lifts. The relationship between adjustment clearance and pivot shaft position yields controlled variation of phase and duration.

Abstract: An internal combustion engine and method for operating the same wherein the combustion chamber volume can be varied depending on throttle position by a member that is inserted into the combustion chamber, and wherein the intake valve is closed before the piston completes its intake stroke so that the expansion stroke is effectively lengthened. In the case of a two-stroke engine, some of the intake gas is expelled before combustion to achieve an effective lengthening of the expansion stroke.