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An automatic forced regeneration ceramic trap system with throttling before the trap, using Ce based fuel additives, for installation on light-duty diesel passenger cars is described. The system was installed on two vehicles and tested in the laboratory. The repeatability of the back pressure variation due to the soot accumulation during successive FTP cycles was determined, and the operation period of the system was defined. The operation of the system in both applications was equivalent to about 35 km of urban driving. The filtration efficiency approached 80% in FTP cycle and 90% in ECE and JAPAN 13 mode tests, while gaseous emissions and fuel consumption were practically not affected by the system.

A model simulating the behavior of the porous ceramic trap was developed. The model is based on the assumption that the pore size of the trap combined with the particle size distribution resulting from the trap oxidising activity defines two areas of trap operation: Ci) accumulation when no pass-through is permitted, and (ii) continuous regeneration when pass-through is permitted. The mathematical evaluation of the model demonstrates that regeneration depends on the ratio of space-time and oxidation process time constant. As far as the lower regeneration limit is concerned, temperature is the main parameter, while the upper regeneration limit is imposed by the low space-time. These dependencies have been experimentally confirmed for the couple of a light-duty Daimler-Benz engine and a Corning EX 47 trap. The test data at the regeneration limits have been correlated on the basis of the model and for continuous oxidation of particle mass flow.