Gm Global Technolgoy Operations, Inc.

Kenneth B Bly

Otto A Ludecke

Richard H Smith

Terrance L Stark

Ernest T Martyniuk

Mark J Gutwald

Edward J Chmiel

David L Dimick

A through flow exhaust particulate filter element of the type including a ceramic monolith structure having a plurality of thin interlaced gas filtering porous internal walls defining a plurality of parallel passages extending to opposite inlet and outlet ends thereof, said passages including a first group comprising inlet passages open at said inlet end of the element and closed by plugs at the outlet end and a second group comprising outlet passages closed by plugs at said inlet end and open at said outlet end, the plugs of the outlet passages at the inlet end of the element being of a ceramic porous material corresponding in porosity substantially to that of the porous internal walls whereby exhaust gases can flow therethrough so that particulates will be trapped by these porous plugs to thus permit flame travel along these plugs to adjacent inlet passages during incineration of collected particulates on the filter element.

Wall-flow monolith filter with porous plugs

A particulate trap for removing particulates from the exhaust flow discharged from a diesel engine comprises a trap housing having an inlet connection and an outlet connection for the exhaust flow, an intermediate filter housing with a support plate positioned between one end of the filter housing and the outlet connection. The support plate is provided with a central one way valve controlled bypass passage extending therethrough and a plurality of closely spaced apart internally threaded apertures therethrough located around the bypass passage. A plurality of filter tubes are operatively supported within the filter housing by the support plate. Each of the filter tubes includes a perforated tube having an externally threaded outlet fitting fixed at one end thereof that is releasably threadingly engaged in an associate one of the apertures in the support plate whereby the perforated tube is supported in cantilever fashion. A closure cap is fixed at the opposite end of the tube with each closure cap being of an external diameter relative to the spacing of the threaded apertures whereby the cap will contact the closure caps on adjacent tubes whereby to support the cantilever ends of these tubes while still permitting axial expansion of the tubes. A coating of ceramic fibers is provided on each perforated tube so as to extend between the outlet fitting and the closure cap, the outside diameter of this coating of ceramic fibers being less than the external diameter of said associate closure cap.

Diesel exhaust particulate trap with plural filter tubes

A particulate trap for use in the exhaust system of a diesel engine to effect removal of particulates from the exhaust gases discharged from the engine, has a trap housing with an exhaust inlet at one end and an exhaust outlet at its opposite end with at least one ceramic monolith wall flow particulate filter having an inlet end and an outlet end positioned in the trap housing by a tubular support member having a mat of refractory material sandwiched between it and a portion of said particulate filter next adjacent to the outlet end thereof in a manner to prevent bypass flow from said exhaust inlet around said particulate to the exhaust outlet, at least 50% of the exterior surface of the particulate filter next adjacent to its inlet end being in spaced apart relationship to the trap housing so as to define a passage in flow communication with the incoming exhaust gases whereby these gases will heat the exterior of the filter next adjacent to the inlet end thereof so as to effect a reduction of the thermal stress on the particulate filter during engine operation. This support arrangement also reduces radial and axial stress on this exposed end of the filter.

Ceramic monolith particulate trap including filter support

A diesel exhaust particulate trap is provided with a heat resistant particulate filter which includes a perforated and pleated metal substrate member coated with a ceramic fiber filter material on its interior surface so as to define a filter chamber for the inside-out flow of exhaust gases through the filter. In a preferred embodiment, an electrical particulate filter igniter is associated with the filter. The igniter includes a trap door pivotably secured to the substrate member, which is normally biased to a closed position by a spring but which can be opened by exhaust flow prior to an accumulation of particulates on the filter. Opening and closing of the trap door is used to effect deenergization and energization, respectively, of an electrical heating element used to initiate combustion of particulates.

Diesel exhaust particulate trap with pleated filter

A self-regenerating diesel engine exhaust particulate filter comprising, in a preferred embodiment, porous ceramic walls defining filter surfaces between adjacent inlet and outlet passages and having electric heating wires in the inlet passages to periodically initiate incineration of collected particulates therein. A movable shield is preferably provided to restrict gas flow through the various passages during their respective periods of incineration so as to provide periodic regeneration with a minimum expenditure of external energy.

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Pontiac, MI, United States of America

Kenneth B Bly