Abstract: An exhaust gas recirculation (EGR) assembly (23) for an internal combustion engine, including an EGR valve (54) having a valve stem (55) reciprocating within a housing (61), between open (FIG. 3) and closed positions. Preferably, the EGR assembly is mounted on the exhaust manifold (15), and the EGR valve can communicate exhaust gas back to the intake manifold (13) in a known manner. The EGR assembly includes an electric motor (41), and a gear train (65) to move the EGR valve (54) in response to changes in an electrical input signal. A plurality of power electronic components (97) are disposed within a controls housing (91), which defines a slot (99) in face-to-face relation to a cooling chamber (81) defined by the housing (61) surrounding the valve stem (55).

Abstract: An exhaust gas recirculation system (11) for an internal combustion engine, including a valve (25) having a closed position (FIG. 2) blocking flow of exhaust gas, the valve being biased by gas pressure in the exhaust gas passage (E) toward a closed position (FIG. 2). The system includes an electric motor (51) having an input gear (55) and a gear train (57,59) driving a sector gear (73). A linkage member (93) has its ends (91,95) connected to the sector gear (73) and the valve stem (29), respectively. The sector gear and the linkage member are configured such that, as the valve begins to open against exhaust gas pressure, the movement of the valve stem is a relatively higher force, and at a relatively lower speed. As the valve moves toward a fully open position (FIG. 7), the movement of the valve stem is at a relatively lower force, but at a relatively higher speed.

Abstract: A roller cam follower for an internal combustion engine. The cam follower includes a roller assembly consisting of an insert member formed of a conformable plastic material and an axleless roller received in a cavity formed in the insert, the material of the insert closely conforming to the contour of the roller. Various adaptations of the inventive cam follower structure are shown; including a light weight mechanical valve lifter, a hydraulic lash adjuster, a rocker arm and a mechanical direct acting tappet; all of which include means for conducting oil from the exterior of the cam follower to the roller cavity.

Abstract: A hydraulic belt tensioner operating on pressurized lubricating oil in an internal combustion engine. The tensioner includes a ratchet mechanism which locks the output member of the tensioner in a fixed position when the engine is not operating and which is disengaged when the engine is operating and the lubricating oil is pressurized. A seal is provided to prevent oil from escaping from the unit. The invention further includes slots formed in a plunger element of the tensioner which are effective to dissipate air which tends to become entrapped under the plunger when the engine is initially started.

Abstract: A hydraulic chain tensioner including a retractable ratchet mechanism. A ratchet pawl in the form of a cylindrical plunger received in a bore formed in the tensioner housing is normally biased into engagement with grooves formed on the output member of the tensioner. The bore is in communication with a source of pressurized engine oil so that when the engine is operating the force produced by the oil pressure acting against the plunger overcomes the biasing force and disengages the plunger from the output member. When the engine is stopped the oil pressure goes to zero and the biasing force is again effective to move the plunger into engagement with the output member to maintain its axial position.

Abstract: A cylinder head gasket for an internal combustion engine which is adapted to compensate for variations in the clamping or hold-down forces which are exerted on the gasket disposed within the joint formed between the cylinder head and the engine block. Because of the spacing of the cylinder head fasteners relative to the ends of the cylinders formed in the block, there are wide areas of the gasket extending between adjacent cylinder ends which are disposed at substantial relative distances from such fasteners. These wide gasket areas are defined at least in part by opposed circumferential segments of the adjacent cylinder ends. Each wide gasket area has a thickness which is substantially greater than the thickness of te remaining portions of the gasket, thereby, resulting in substantially uniform clamping forces being exerted throughout the gasket.