초록 ▼

A number of embodiments of overhead cam internal combustion engines having multiple intake and exhaust valves. The valve actuating mechanism is such that the valves are opened at a non-symmetrical rate so as to minimize the clearance requirements at top dead center and also so as to minimize the ove

A number of embodiments of overhead cam internal combustion engines having multiple intake and exhaust valves. The valve actuating mechanism is such that the valves are opened at a non-symmetrical rate so as to minimize the clearance requirements at top dead center and also so as to minimize the overlap between the closing of the exhaust valve and the opening of the intake valve without decreasing volumetric efficiency. A number of embodiments having either direct or rocker arm actuation are disclosed.

대표청구항 ▼

An internal combustion engine comprised of a cylinder block having a cylinder bore with a piston reciprocating therein, a cylinder head closing said cylinder bore and having a surface which defines a combustion chamber with said cylinder bore and a head of said piston, said cylinder head surface def

An internal combustion engine comprised of a cylinder block having a cylinder bore with a piston reciprocating therein, a cylinder head closing said cylinder bore and having a surface which defines a combustion chamber with said cylinder bore and a head of said piston, said cylinder head surface defining a plurality of intake valve seats generally on one side of said combustion chamber and a plurality of exhaust valve seats generally on the other side of said combustion chamber, the valve seats of one of said plurality defining a substantially greater effective flow area than the valve seats of the other plurality, a plurality of poppet-type intake valves slidably supported by said cylinder head and controlling the flow through said intake valve seats, a plurality of poppet-type exhaust valves slidably supported by said cylinder head and cooperating with said exhaust valve seats for controlling the flow therethrough, actuating means for actuating said valves between their open and their closed positions, said actuating means being effective to cause non-symmetrical opening and closing of at least one of said valves so that it opens at a different rate than it closes, said actuating means comprising a camshaft rotatable about an axis and operating said valve through a thimble tappet, said different rate of opening and closing being achieved through profiles of a cam on said camshaft, said axis of rotation of said camshaft being offset from an axis of reciprocation of said tappet actuated thereby in a direction so that the side of said cam that effects the more rapid movement will contact the side of said tappet opposite to the direction of offset, said axis of reciprocation of said tappet being offset from the center of said cam so that said cam will effect rotation of said tappet in addition to reciprocation thereof.