Valve timing system with rotation of cam followers to provide earlier or later engagement between cam and followers

摘要

A variable valve timing system is applicable for vary the opening and closing cycle of the inlet and outlet valves of an internal combustion engine. The system comprises a cam follower (4) and a cam (1) which is rotated about the cam shaft (3) to move the valve between its open and closed position. To vary the cycle of the opening and closing of the valves, a rotational means (not shown) is connected to the cam follower (4) to rotate the cam follower (4) such that the cam follower (4) and cam (1) are out of alignment such that the cam lobe engages the contact surface (2) at a higher point and hence earlier than if the cam follower (4) and the cam (1) are aligned. Therefore the valve is opened sooner and closed later, increasing the degrees of cycle for which the valve is open, for example, as the engine revolutions increase.