Impact of Continuous-Regeneration Particulate Filters on Gaseous Pollutant Emissions of Diesel Engines

With increasingly stringent international limits on diesel particulate matter emissions, Continuous-Regeneration Particulate Filters (CRPFs) have been widely applied in heavy-duty vehicle (HDV) exhaust systems. However, their impacts on the complete gaseous pollutant profile remain insufficiently characterized. This study investigated the effects of three CRPF configurations on gaseous emissions from a China III diesel engine under the World Harmonized Transient Cycle (WHTC). Regulated pollutants (CO, total hydrocarbons (THC), NOx, and CO2) and unregulated pollutants (benzene series compounds and aldehydes) were measured before and after CRPF installation. The results demonstrated that CRPFs achieved high reduction efficiencies for CO (98.5–99.9%) and THC (77.4–99.9%) through catalytic oxidation, while showing negligible effects on NOx (0.2–3.0% reduction) and slight increases in CO2 (0.07–0.55%). For unregulated pollutants, aldehydes were effectively reduced (formaldehyde: 84.1–100.0%; acetaldehyde: 47.4–100.0%), whereas benzene series compounds exhibited variable responses, with some species showing increased emissions. These findings reveal complex pollutant transformation mechanisms within CRPF systems and provide references for optimizing aftertreatment configurations to meet China VI and subsequent emission standards, thereby contributing to the mitigation of air pollution, the protection of public health, and the promotion of sustainable societal development.