Diesel particulate traps regenerated by catalytic combustion

The development of catalytic means for the regeneration of particulate-laden traps for diesel exhaust cleaning is the main topic of this paper. All the steps of the catalytic trap preparation are dealt with, including: the synthesis and choice of the proper catalyst and trap materials, the development of in situ catalyst deposition, and the bench testing of the derived catalytic traps. Two different traps were considered (i.e., silicon carbide and cordierite wall-flow monoliths operating via a shallow-bed filtration mechanism), whereas the best catalyst selected was the perovskite LaCr0.9O3. The filtration efficiency and the pressure drops of the catalytic and non-catalytic monoliths were evaluated on a diesel engine bench under various operating conditions. On the basis of the obtained results the catalysed SiC converter was found to be the most satisfactory converter to be placed on the exhaust line of the modem common-rail diesel-engine cars.