Gm Global Technolgoy Operations, Inc.

Terry Wayne Black

Alan William Hayman

James Joseph Mazzola, Iii

Frederick J Rozario

An engine assembly includes an engine block defining a first cylinder bore, a second cylinder bore directly adjacent to the first cylinder bore and a third cylinder bore directly adjacent to the second cylinder bore. The engine block defines a first distance from a diametrical center of the first cylinder bore to a diametrical center of the second cylinder bore and defines a second distance from the diametrical center of the second cylinder bore to a diametrical center of the third cylinder bore. The first distance is different than the second distance.

Engine assembly including multiple bore center pitch dimensions

A valve train layout for an overhead valve engine uses a single camshaft actuating two inlet valves and a single exhaust valve. The two inlet valves are preferably aligned on an inner side of a cylinder with the exhaust valve on an outer side. The inlet valves are preferably actuated by a cam follower and single push rod driving a rocker arm with dual arms and separate lash adjusters actuating the inlet valves. The exhaust valve is preferably actuated by a cam follower with a lash adjuster driving a single push rod operating a primary rocker arm that drives a secondary push rod pivoting an exhaust rocker arm to actuate the exhaust valve. In one embodiment, the primary rocker arm for the exhaust valve pivots on a common axis with the intake rocker arm. In an alternative embodiment, the primary rocker arm pivots on a canted pivot axis.

Single cam three-valve engine overhead valve train

A valve train with components connected by ball and socket joints is provided with projecting assembly guides adjacent the sockets of selected joints. The assembly guides include guide surfaces angling toward the sockets to guide the ball end of a push rod or other actuator into the socket of an associated rocker arm or other component. The guide surfaces may be generally conical or comprised of multiple spaced surfaces. The assembly guides facilitate assembly of valve trains, especially where components with multiple ball and socket joints are involved.

Valve train with assembly guides

An engine assembly is disclosed which includes a cylinder block having cylinders, pistons disposed in the cylinders, and connecting rods connecting the pistons to a crankshaft. The crankshaft rotates to move the pistons reciprocally in the cylinders thereby inducing volumetric changes within the engine and, particularly between axially adjacent pistons. A crankcase disposed below the cylinder block has axial sidewalls extending therefrom to define a crankcase volume in which the crankshaft is disposed for rotation. Crankcase bulkheads extend laterally to connect the axial walls and define cylinder bays therebetween. Each of the crankcase bulkheads includes a crankshaft journal support and a surface configured to rotatably receive a complementary bearing cap for support of the crankshaft therebetween. The sidewalls include outwardly relieved portions at the intersection of the bulkheads with the crankcase sidewalls to define openings around the bearing caps to allow airflow, induced by the volumetric changes, between the cylinder bays.

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Clarkston, MI, United States of America

Terry Wayne Black