<div class="htmlview paragraph">This paper describes the system modification through the improvement of pulse air penetration into the DPF cell channels in respect to the development of a wall-flow type diesel particulate filter ( DPF ) system with reverse pulse air regeneration for diesel vehicles.</div> <div class="htmlview paragraph">In this system, regeneration becomes more difficult with low exhaust gas temperatures and increased DPF volume. The pressure increase in the DPF cell channels was monitored as a parameter of pulse air penetration when reverse pulse air was injected into the DPF. By maximizing the pressure increase, the pulse air injection system was modified. The modification includes various changes in the air pipe arrangement and the air injecting time. The ratio of the length to the diameter of the DPF was also evaluated in relation to the regeneration efficiency.</div> <div class="htmlview paragraph">In this study, the high aspect ratio, i.e. small diameter and long DPF, showed better regeneration efficiency. The results of this study indicate that this system can be enlarged with the above modification despite low exhaust gas temperatures.</div>