Overhead camshaft layout for IC engine - has followers arranged to trail against cam faces and lift away from pressure faces

摘要

The engine has an overhead camshaft (5) which is placed between the rocker arms (5, 6) of the inlet (2) and exhaust (3) valves. The pivot (7) of the inlet rocker arm is between the camshaft and the valve head and the pivot (10) of the exhaust rocker arm is at the end of the arm beyond the valve head. The pivots and camshaft are positioned in relation to each other so that the frictional forces (A, B) between the cam and the two followers (8, 9) produce moments (MA, MB) tending to lift both rocker arms off the cam. A moment in this direction on both rocker arms makes lubrication of the cam less critical than if one of the rocker arms tends to be pressed onto the cam.