Patent ID: 7849681

Claim:
An apparatus for utilizing engine-generated heat in a NO x -adsorber system comprising a combustion device having disposed therein a heating chamber that generates a heated exhaust products stream, the apparatus comprising: an upstream downpipe segment that receives the heated exhaust products stream, and delivers the exhaust products stream to a catalytic component, the upstream downpipe segment comprising heat loss reduction features configured to reduce the amount of heat transfer from the heated exhaust products stream in the upstream downpipe segment through a wall of the upstream downpipe segment, each heat loss reduction feature being defined by at least one property of the upstream downpipe segment, wherein the properties of the heat loss reduction features are preselected to achieve a temperature of the heated exhaust products stream exiting the upstream downpipe segment at or above a predetermined minimum temperature based on a predicted temperature of the heated exhaust products stream entering the upstream downpipe segment, a predicted temperature of the space immediately surrounding the upstream downpipe segment during normal operating conditions of the engine, and an estimated maximum allowable heat loss through a wall of the upstream downpipe segment, and wherein the heat loss reduction features comprise a reduced heat transfer area of the upstream downpipe segment and a reduced thermal conductivity of the wall of the upstream downpipe segment, wherein the at least one preselected property of the reduced heat transfer area comprises a predetermined length reduction of the upstream downpipe segment and the at least one preselected property of the reduced thermal conductivity of the wall comprises a predetermined increase in insulation surrounding the upstream downpipe segment; the catalytic component comprising a catalyst on a substrate whereby the catalyst is configured to initiate at least one exhaust conditioning reaction within the heated exhaust products stream for temperatures of the heated exhaust products stream only at or above the predetermined minimum temperature; a downstream downpipe segment in fluid communication with the catalytic component, such that the downstream downpipe receives the exhaust products stream from the catalytic component and delivers the exhaust products stream to a nitrogen-oxide adsorption catalyst (NAC); and the NAC comprising a NO x adsorbing and NO x reducing catalyst on a substrate.