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The effects of the factors of reverse pulse air regeneration; pulse air pressure, pulse air time and pulse air interval, were evaluated. Pulse air pressure significantly affects a DPF's pressure drop increase. Pulse air time and pulse air interval do not greatly affect a DPF's pressure drop. Current DPFs and samples with modified materials were tested. The pressure drop increse varied with the material properties, such as mean pore size and porosity. Current DPFs are applicable to a DPF system with reverse pulse air regeneration. There is the possibility to get an optimum DPF for the reverse pulse air regeneration system by changing the mean pore size, porosity and/or other properties.

In this study, to satisfy increasingly strict emission regulations, the conversion efficiency of a 0.11 mm (4 mil) thin-wall catalyst is discussed. The effects of catalyst bulk density on reducing heat mass to improve catalyst emission conversion in the early cold transient mode (Bag 1 in the FTP-75 mode) is quantitatively discussed. To analyze the effects of low heat mass, catalyst's bed temperatures were measured. Effects of the geometric surface area (GSA) and volume of the catalyst were also analyzed. An early feedback control system with an HEGO oxygen sensor and a secondary air injection control system with an original oxygen sensor were compared with an original control system on THC, CO, and NOx emission amounts.

A wall-flow type diesel particulate filter system with reverse pulse air developed for vehicles should have the best regeneration performance possible with the least reverse pulse air as possible. We improved the reverse pulse air arrangement to decrease the air consumption and raise regeneration performance. Then, we developed diesel particulate filter (DPF) materials for the pore structure suitable for regeneration. Test equipment was designed to consume less air than a previous prototype system presented in our SAE paper [1]. The experiments used a soot generator simulating a diesel engine and a diesel engine. We confirmed that a wall-flow type DPF could possibly be applied to a regeneration system with the low air consumption for mounting on vehicles.