Abstract: An anti-coking bushing assembly for sealing a pintle shaft of an EGR control valve, comprising a bushing carrier disposed in the valve body and supportive of close-fitting pintle shaft bushing liners formed of a polyimide such as Vespel. The bushing carrier and bushing liners are installed into a carbon shield extending into the exhaust flow space within the valve. Within the carbon shield, between the gas flow space and the bushing carrier, is a ring seal on the pintle shaft and a gas expansion chamber to cool exhaust gas escaping along the pintle shaft, allowing contaminants in the exhaust gas to precipitate in the gas expansion chamber. The carbon shield, ring seal, bushing carrier, and bushing liners are conveniently pre-assembled as an anti-coking bushing assembly for subsequent installation into a valve body during final valve assembly.

Abstract: An anti-coking bushing assembly for sealing a pintle shaft of an EGR control valve, comprising a bushing carrier disposed in the valve body and supportive of close-fitting pintle shaft bushing liners formed of a polyimide such as Vespel. The bushing carrier and bushing liners are installed into a carbon shield extending into the exhaust flow space within the valve. Within the carbon shield, between the gas flow space and the bushing carrier, is a ring seal on the pintle shaft and a gas expansion chamber to cool exhaust gas escaping along the pintle shaft, allowing contaminants in the exhaust gas to precipitate in the gas expansion chamber. The carbon shield, ring seal, bushing carrier, and bushing liners are conveniently pre-assembled as an anti-coking bushing assembly for subsequent installation into a valve body during final valve assembly.

Abstract: A motorized cam actuator for linear actuation of an apparatus. An actuating motor shaft is fitted with a bushing having first and second opposed flats and a threaded portion at an outer end thereof. With the motor mounted to a pedestal, the bushing is rotated on the shaft to a predetermined angular position such that assembly stack up is cancelled. The bushing is then fixed to the shaft by welding. A cam with a central opening is mounted onto the bushing, the opening having flats for mating with the flats on the bushing. The cam is mounted onto the bushing and is secured thereto by a nut. This arrangement eliminates any relative motion between the bushing and the motor shaft and prevents stress on the weld joint from reaching failure levels.

Abstract: An exhaust gas recirculation valve having a reciprocating pintle shaft supported by a sleeve bushing and having a labyrinthine pathway between a valve operating chamber and a shaft/bushing interface to minimize intrusion of exhaust gases into the interface. The labyrinthine pathway is formed between fixed annular elements of the valve body and shaft bushing and a movable annular element of the valve head telescopically disposed between the fixed elements.

Abstract: In a solenoid-actuated pintle valve assembly, the solenoid assembly is shrouded by a manifold jacket connected via an opening to a source of air at a pressure higher than the working gas pressure within the valve chamber. During operation of the valve and solenoid assembly, a low mass flow of air is forced continuously throughout the solenoid assembly and exits through any leaks in the jacket and along the bushing bores into the valve chamber. Thus, the bushing bore and solenoid assembly are actively protected against entry of contaminants. Further, since it is no longer necessary to vent the valve to permit the escape of gases leaking along the bushing bores, contaminant-laden gases are kept from being exhausted into the engine compartment and from leaving a carbon track residue. The invention is especially useful for exhaust gas recirculation valves on internal combustion engines.

Abstract: An exhaust gas recirculation valve having a reciprocating pintle shaft supported by a sleeve bushing and having a labyrinthine pathway between a valve operating chamber and a shaft/bushing interface to minimize intrusion of exhaust gases into the interface. The labyrinthine pathway is formed between fixed annular elements of the valve body and shaft bushing and a movable annular element of the valve head telescopically disposed between the fixed elements.

Abstract: A system for seating a head of a valve shaft that is received within a first axial bore in a primary bushing includes a second bushing having a second axial bore. The second axial bore has a second bore diameter, and is substantially concentric relative to the first axial bore. The valve shaft has a first shaft portion and a second shaft portion. The first portion has a first portion diameter, and the second portion has a second portion diameter. The first portion diameter is a predetermined amount less than the second bore diameter, whereas the second portion diameter is substantially equal to the second bore diameter. The first shaft portion is received within the second axial bore when the valve shaft is in the closed position. The second shaft portion is received within the second axial bore when the valve shaft is in the open position.

Abstract: An integral pintle shield and annular scraper for protecting and cleaning the pintle shaft of a pintle valve, such as an exhaust gas recirculation valve for an internal combustion engine, to prevent coking and failure of the valve. The scraper surrounds the shaft, making contact with the shaft surface with sufficient force to dislodge incipient coke deposits but with insufficient force to inhibit the axial motion of the pintle shaft in actuation. The scraper is mounted within a radial shield surrounding the pintle shaft and pintle bushing for preventing exposure of the shaft and bushing to combustion products. The scraper is disposed in such a way that the shaft is scraped in both directions during each actuative cycle of the valve.

Abstract: A poppet valve has a pintle shaft radially supported by a primary bushing and supporting a valve head near the distal end of the shaft for mating with a valve seat surrounding a port in a wall of the valve housing. The shaft is further supported, either inboard or outboard of the valve head, by a secondary bushing means. The shaft is radially and non-compliantly supported by the secondary bushing through a first and major portion of the valve's axial length. A second portion of the shaft which is within or entering the secondary bushing just as the valve closes is provided with a reduced diameter, such that the shaft then is not radially supported by the secondary bushing and the valve head may freely self-center on the valve seat.

Abstract: A short-stroke solenoid-actuated valve suitable for pulsewidth modulated operation including a plurality of components formed of powdered metal, preferably a 400-series stainless steel compressed to about 6.0 g/cm3, to be sound absorptive and ferromagnetic; resilient radial seal means disposed in an annular groove in an outer surface of the valve for sealing against a cylindrical receiving surface; metal mesh shaft seal means for inhibiting leakage from the valve into the actuator; and a dielectric polymeric encapsulant loaded with a thermally conductive particulate substance to increase the heat-transfer modulus of the encapsulant.