Temperature characteristics of silicon carbide particulate filter during drop-to-idle regeneration applied to a diesel vehicle

During the active regeneration process, engine speed may drop to idle (DTI) under extreme circumstances, where the diesel particulate filter (DPF) is subjected to severe thermal stress that can cause DPF cracks. To prevent the filter thermal damage, this study investigated the temperature variation of silicon carbide (SiC) substrate with different vehicle speed, initial soot load, regeneration duration and target DTI regeneration temperature under the real vehicle road conditions. The results showed that the peak temperature and temperature gradient were greatly increased at the rear end of DPF. The radial temperature distribution in DPF was not uniform, and the heat convection in outer rings was especially significant. The maximum temperature and maximum temperature gradient increased as the PM load and target DTI regeneration temperature increased, whereas vehicle speed and regeneration duration had the opposite effect. Similar results were also found in regeneration efficiency. To enable better regeneration performance and fuel economy within the DPF heat capacity, appropriate soot load threshold and target DTI regeneration temperature should be carefully selected. Finally, the linear models for predicting the maximum temperature and maximum temperature gradient of DPF regeneration were developed based on experimental data, the linear models' average errors were 1.06% and 2.66%, respectively, and could be used to determine the temperature curve and the soot load threshold for safe regeneration.