Hydrocarbon emission control of an adsorptive catalytic gasoline particulate filter during cold-start period of the gasoline engine

Abstract

In order to reduce HC emission of the gasoline engine during cold start to meet increasingly stringent emission standards, an adsorptive catalytic gasoline particulate filter (A-CGPF) is proposed and a mathematical model of the A-CGPF is established. Then, HC adsorption performance, conversion performance and abatement performance of the A-CGPF coated with different catalyst under different inlet HC concentration are investigated during cold start. The results show that inlet HC concentration, exhaust temperature has great influence on the adsorption process, while mass flow rate has little influence; penetration time decreases with the increase of inlet hydrocarbon concentration. In addition, the catalytic conversion performance order is MCA > Rh–Pd > CeO2 > PCZ > Pd under adiabatic condition, their corresponding light-off time is 10s, 34s, 56.4s, 57s and 57.2s, respectively. Compared with the A-CGPF coated with adsorbent or catalyst, adsorption duration time of the A-CGPF coated with composite adsorptive catalysts is shortened, and its catalytic oxidation stage is advanced; the cumulative HC emission in the first 40s of the cold start phase is significantly reduced and the HC removal rate is increased; the HC removal performance order is MMC > MRP > MC > MP > MPCZ, and the HC removal blank period due to interaction effect between adsorption and catalytic oxidation can be properly shortened. Moreover, the inlet HC concentration fluctuation results in the deterioration of carrier temperature rise, prolongs the removal blank period, and decreases the HC removal rate at the initial stage of cold start. Compound rare earth oxide MCA has better HC abatement performance than other catalysts. This work provides reference for hydrocarbon abatement performance enhancement of a GDI engine and design of coupled after-treatment system.