Emission reduction characteristics of an active-passive combined regeneration diesel particulate filter

To study the influence of active-passive combined regeneration diesel particulate filters (DPFs) on heavy-duty vehicle emissions, an active-passive combined regeneration DPF installed on the exhaust pipe of a diesel engine meeting China Ⅲ emission standard was tested on the engine bench. The emission reduction performance of CO₂, conventional gaseous pollutants (CO, THC, NO_x), particulate matter (PM) and number (PN), and unconventional pollutants (benzene series, aldehydes and ketones) was analyzed. The results showed that the DPF increased CO₂ emission of the diesel engine by about 0.30% under the WHTC operation cycle while having a high emission reduction effect on PM, PN, CO and THC. The average reduction efficiency of particulate matter, particulate number, CO and THC was 93.81%, 98.90%, 94.03% and 95.53%, respectively. However, this PDF had a low NO_x average reduction efficiency of only 5.35%. The unconventional pollutants analysis showed that the DPF had a certain reduction effect on most of the benzene series, aldehydes and ketones except for benzaldehyde, which was increased by about 34.26%. The results can provide reference for diesel vehicle manufacturers to install diesel particulate filters on heavy-duty vehicles to meet the China Ⅵ emission standard.