Caterpillar Inc.

Kenneth J Suda

Robert Lowell Miller

Chuong Q Dam

Keith Edward Lawrence

Christopher F Gallmeyer

Michael Aaron Caruthers

Kerry Allen Delvecchio

Kent A Koshkarian

Kenneth A Baumgartner

William J Hays

An AC glow plug system is provided that includes a static converter for DC to AC conversion. Control techniques include varying the converter duty cycle according to glow plug temperature and other parameters such as engine air or coolant temperatures for smooth running as well as for prolonging glow plug life. Control is also varied according to fuel system characteristics and fuel composition.

Engine glow plug systems and methods

A glow plug shield centrally receives a glow plug which, typically, has a silicon nitride surface. The shield and plug are spaced radially from a fuel injector disposed centrally of a cylinder head. The shield and glow plug extend into a combustion chamber where the shield has an oblique end exposing the circumferential portion of the plug which faces the injector. This shield configuration protects the glow plug from cooling by inlet air, increases the residence time of air/fuel mixture around the plug, and improves flame propagation so that plug temperature and electrical power can be reduced to extend glow plug life. The shield has a coating exteriorly and interiorly covering the portion of the shield extended into the combustion chamber. The coating is of thermally insulating, high temperature resistant ceramic material and acts as a thermal barrier to further reduce glow plug cooling. A combustion catalyst such as platinum or palladium may be incorporated into the coating to further reduce the required glow plug temperature and electrical power.

Glow plug shield with thermal barrier coating and ignition catalyst

A glow plug assembly having a shield integrally connected to a housing is disposed in and retained in a bore in a cylinder head by a clamp connected to the cylinder head. A stop surface connected to said housing is engageable with the cylinder head and establishes the location of a heating element second end in the combustion chamber. The clamp maintains the stop against the head and the orientation of the shield angled second end relative to the combustion chamber. The heating element is connected to the housing by a spacer and the housing is sealed with a filler material which blocks the transfer of fluid through the housing. The filler material maintains the housing from passing fluid between the first and second housing ends, minimizes the vibration of the electrical conductors and conducts the heat out of the glow plug.

Glow plug assembly

A liquid propane injection system for a diesel engine includes a liquid propane fuel tank, a pump, a heat exchanger, a reservoir, and an injector. The pump receives liquid propane from the liquid propane fuel tank, and increases the pressure of the received liquid propane to a level suitable for use by the diesel engine. The heat exchanger receives liquid propane from the pump, and vaporizes the liquid propane. The reservoir stores vaporized liquid propane received from the heat exchanger, and has sufficient storage capacity to compensate for any time lag between instantaneous engine fuel demand and the supply of liquid propane by the pump. The injector receives vaporized liquid propane from the reservoir, and injects the vaporized liquid propane into a combustion chamber of the diesel engine.

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Edelstein, IL, United States of America

Kenneth J Suda