Experimental study on the temperature characteristics of a diesel particulate filter during a drop to idle active regeneration process

Abstract

When the active regeneration of a diesel particulate filter (DPF) occurs during a drop to idle (DTI) process, a massive amount of heat accumulates in the DPF, leading to a rather high peak temperature and a large temperature gradient, which can damage the DPF. Therefore, this study focuses on the temperature characteristics of a DPF in DTI active regeneration, so as to avoid the DPF damage at high temperature and large temperature gradient. The effects of particulate matter (PM) load, target regeneration temperature, and mass flow of exhaust gas on the temperature characteristics were investigated in this study. The peak temperature was found in the center of the outlet section of the DPF, the temperature gradient in the radial direction was much larger than that in the axial direction, and the maximum temperature gradient appeared near the outer surface of the DPF, that’s where the cracks are most likely to occur. In general, with the increase of PM load and target regeneration temperature, the peak temperature and the maximum temperature gradient of the DPF both increased, whereas they declined with the increase of mass flow of exhaust gas. Especially, decreasing PM load and increasing mass flow were very effective to decrease the maximum temperature gradient. Based on the experiments, two linear models were established to predict the peak temperature and the maximum temperature gradient of the DPF in DTI active regeneration respectively. Furthermore, the soot mass limit (SML) of the DPF was determined based on a series of DTI active regeneration experiments.