Temperature Distribution in Sintered Metal Diesel Particulate Trap at Active-Regeneration Conditions

This paper describes measurements and analysis of the temperature distribution inside an uncoated sintered metal diesel particulate trap (SMT) during active regeneration tests. A model for the heat transfer between the exhaust gas and SMT is given, which can be used to limit future tests on the thermal performance of the filter. The SMT is placed behind a medium duty truck diesel engine on a stationary dyno test bench. Step-like temperature changes were initiated by dosing diesel fuel upstream of an oxidation catalyst (DOC) or by dropping the engine from a stationary operation point into idle. Measurements were performed on non-soot laden filters to study the thermal behavior. The data are interpreted by a heat transfer model. In comparable tests with soot laden filters, temperature data were obtained during complete regenerations and during drop-to-idle interrupted regenerations. In this test, peak temperatures were locally found inside the filter. Temperature peaks downstream the SMT were not observed due to the high thermal conductivity and the high specific heat of the filter which buffers the exothermic soot combustion very effectively.