Abstract: A piston has a one-piece, preferably cast aluminum, piston head with a cooling oil gallery completely surrounded by and within the head. The piston head has a pin bore for a piston pin that does not intersect with the cooling oil gallery. The pin bore is sized to maintain a substantially uniform clearance between the piston pin and the piston head. The piston head has a passage extending from the pin bore to the cooling oil gallery to allow cooling oil from the gallery to lubricate the piston pin. The passage is preferably drilled after the piston head is cast. Preferably, the pin bore does not have a recess at the passage. A method of manufacturing a piston includes casting the one-piece piston head and drilling a passage from the pin bore to the cooling oil gallery.

Abstract: An engine control system in a vehicle including a variable displacement internal combustion engine, an intake manifold coupled to the variable displacement internal combustion engine, a controller for controlling the displacement of the variable displacement internal combustion engine, and where the controller varies the spark for a reactivating cylinder during the transition from deactivation to reactivation.

Abstract: An engine control system in a vehicle including a variable displacement internal combustion engine, an intake manifold coupled to the variable displacement internal combustion engine, a controller for controlling the displacement of the variable displacement internal combustion engine, and where the controller varies the spark for a reactivating cylinder during the transition from deactivation to reactivation.

Abstract: A secondary air injection system for reducing the hydrocarbon emissions of an internal combustion engine that is provided with an air pump supplying air to the exhaust manifold of the engine through a check valve assembly and an elastomeric hose characterized in that a baffle in the shape of a helix is located internally within the hose so as to cause the exhaust pressure waves from the engine and passing beyond the check valve assembly to impinge upon the solid compound surface of the baffle and be divided and diffused as they progress along spiraling paths so as to prevent objectionable noises being generated in the hose by the pressure waves.