Method and apparatus for filtering solid particulate matter from diesel engine exhaust

In a method for decreasing the emission of soot from diesel engine which includes the steps of passing the engine's exhaust flow through at least a part of filter means having at least one filter element in a single filter zone, said filter element being selected from the group consisting of ceramic honeycomb filter structure, sintered porous metal material, metal mesh, ceramic foam and granular bed to trap solid matter from said exhaust flow, interrupting said exhaust flow through at least said part of the filter means for up to one second, passing, during said interruption, at least one backflush fluid pulse, said pulse being generated by the intake pull of the diesel engine, through at least said part of the filter means thereby to dislodge from the filter means and entrain, said solid particulate matter, and transporting said dislodged particulate matter to the intake of said engine so that a portion of said matter can be combusted in the engine, the improvement comprising the further step of substantially continuously purging a portion of the accumulated, noncombustible solid particulate from said engine.

In a diesel engine, improved apparatus for decreasing exhaust emissions having filter means positioned to intercept the engine's exhaust flow and trap solid particulate matter contained initially in the exhaust when that exhaust flows through at least part of said exhaust flow, means for periodically interrupting the exhaust flow through at least said part of the filter means, means for passing, during said interruption, at least one backflush fluid pulse through at least said part of the filter means thereby to dislodge said particulate matter from the filter means, and entrain said solid particulate matter, means for transporting said dislodged solid particulate matter to said engine so that said matter can be combusted in the engine, wherein the improvement comprises filter bypass means for periodically removing any accumulated noncombustible solid particulate from said engine, said filter bypass means comprising a normally closed valving means which is opened after between 3 and 50 pulses, said valving means being opened after a pulse and before said particulate has become again trapped on said filter means.

In a diesel engine, improved apparatus for decreasing exhaust emissions having a filter means selected from the group consisting of ceramic honeycomb filter structure, sintered porous metal material, metal mesh, ceramic fiber, ceramic foam and granular bed, said filter means having a single filter zone which is positioned to intercept the exhaust flow of said engine and which traps solid particulate matter contained in the exhaust flow of said engine when that exhaust flows through said filter zone, thereby to remove said matter from the exhaust flow, means for interrupting the exhaust flow through said filter zone for up to one second, means for passing, during said interruption, a backflush fluid pulse through said filter zone thereby to dislodge from the filter means, and entrain, said solid particulate matter, said backflush fluid pulse being generated by the intake pull of the diesel engine, means for transporting said dislodged solid particulate matter to the engine so that said matter can be combusted in the engine, wherein the improvement comprises purge means for substantially continuously removing any accumulated noncombustible solid particulate from said engine.