Performance of Pellet-Packed Bed for Trapping Diesel Particulates

Abstract

This paper deals with a pellet-packed bed for trapping diesel particulates. This trap has the labyrinths of the flow passage which favors inertial impaction to ceramic pellets, ensuring the required trap efficiency with a longer lifetime prior to clogging as long as the appropriate pellet diameter and trap size are selected. Experiments were made on a single-cylinder test engine to investigate the trap efficiency, pressure loss and effects on engine performance. From the comparison of the test results with those of the ceramic monolith filter, it is shown that the pellet-packed bed has smaller pressure loss during engine operation than the monolith. This enables us to maintain a higher trap efficiency with less sacrifice of engine performance for a longer time. It is noted that the soluble organic fraction in particulate matter can also be trapped because of its greater specific surface area. Trap regeneration and pellet material are discussed from the practical point of view.