Method and device for removing soot from exhaust gases
AssigneeFilterwerk Mann & Hummel GmbH
InventorsHans Erdmannsdorfer, Manfred Wagner, Gerd Weyh
Life of this patent
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Abstract
A method and device for removing soot from the exhaust gases of a diesel-type internal combustion engine, using a soot filter in the exhaust line and a dosing device which injects a dose of a combustion-inducing substance, for example CuCl, into the soot filter by means of compressed air. The soot-combusting process is initiated automatically, in response to a critical exhaust pressure level and the simultaneous presence of a suitable temperature in the soot filter, using a pressure switch and a series-connected thermal switch. Compressed air, flowing through a bypass line, scavenges the supply line of the combustion-inducing substance, while supplying additional oxygen for the soot combustion process.
Claims15
A method of removing soot from the exhaust gases of an internal combustion engine, particularly of a diesel engine, comprising the steps of:
- filtering the soot particles from the exhaust gas by means of an exhaust filter which retains and collects the soot;
- during operation of the engine, from time to time burning off the collected soot to a gas which passes through the exhaust filter by adding to the soot a dose of a flowable combustion-inducing substance which lowers the soot ignition temperature and a supply of combustion air;
- monitoring the temperature inside the exhaust filter and using the presence of an operating temperature above a predetermined level as a precondition for the initiation of the burn-off step;
- and
- monitoring the accumulation of soot in the exhaust filter, in terms of the resultant increase in the flow resistance of the filter, and using the presence of a predetermined flow resistance as a trigger condition for the initiation of the burn-off step.
A device for removing soot from the exhaust gases of an internal combustion engine, particularly of a diesel engine, comprising in combination;
- an exhaust filter, including a housing, an exhaust gas inlet, an exhaust gas outlet, and a gas-permeable heat-resistant filter body subdividing the interior of the housing into a raw gas chamber upstream of the filter body and a clean gas chamber downstream thereof, the filter body being adapted to filter soot particles from the passing exhaust gas and to collect the retained soot particles;
- and
- means for feeding into the exhaust filter and sprinkling onto the collected soot a dose of combustion-inducing substance which lowers the soot ignition temperature, said feeding means including:
- a source of compressed air and air conduit means leading from said source into the exhaust filter, upstream of the filter body;
- valve means in the air conduit means for enabling, from time to time, a flow of compressed air to enter the exhaust filter, the flow of compressed air thereby serving to convey said substance into the exhaust filter and to sprinkle it onto the collected soot, while also supplying oxygen for the combustion of the latter;
- and
- dosing means for metering into said flow of compressed air a predetermined quantity of the combustion-inducing substance, as required to burn off the collected soot to a gas which passes through the filter body.
Dependencies are inferred from the claim text.