Four stroke internal combustion engine

摘要

The engine has two side (6,7) and one central (8) inlet valve per cylinder (2), all controlled by one camshaft (9). Another camshaft (10) controls two outlet valves (4,5). The engine's inlet drag lever (13) has a turning angle ( alpha ) and a length (L) to define a maximum lift for the first valves. The side valves' axes' (19) angle of inclination ( beta 1) to the cylinder's longitudinal central plane (3) is steeper than that ( beta 2) of the central's (20). In a projection from a cross plane to the central plane, the ends (25) of the side valves are spaced apart from that (26) of the central valve, so that the effective lever length between them and the drag lever's pivot point (15) differ. This length difference is minimised by the arrangement of this pivot point and raised surfaces (23,24) atop the shafts.