Behavior of particulate accumulation/removal on porous filter was studied. Optimum elements of effective reverse cleaning regeneration were examined.DPF system with cross flow filter and pulse jet cleaning (APT) was applied to city bus application. Its trap efficiency was evaluated by California Air Resources Board. Two terms of fleet test were conducted in Los Angeles area. First test demonstrated serviceability of reverse cleaning regeneration, filter and high trap efficiency It accumulated 4340 mile and proved filter durability Size-reduced second APT had negative effect of turbulent flow to the particulate burning area.