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In order to study the influence of lubricant ash on the performance of the CN6 after-treatment system, especially the catalyst characteristics of Coated Gasoline Particulate Filter (CGPF), the system was rapidly aged on the engine bench by blending combustion method, and the ash content of 60g represented the endurance of 200kkm CGPF. The effects of CGPF with different endurance mileage on particulate matter emission, gas light-off temperature and engine performance of a Gasoline Direct Injection (GDI) vehicle were studied on the engine bench, chassis dynamometer and real-road tests. Finally, the ash distribution was analyzed by computed tomography (CT). The results showed that the vehicle equipped with CGPF could meet the requirements of CN6 particulate and gas emission limits under both worldwide harmonized light vehicles test cycle (WLTC) and real driving emission (RDE) tests.

Gasoline particulate filter (GPF) is considered a suitable solution to meet the increasingly stringent particle number (PN) regulations for both gasoline direct injection (GDI) and multi-port fuel injection (MPI) engines. Generally, GDI engines emit more particulate matter (PM) and PN. In recent years, GDI engines have gained significant market penetration in the automobile industry owing to better fuel economy and drivability. In this study, an accelerated ash loading method was tested by doping lubricating oil into the fuel for a GDI engine. Emission tests were performed at different ash loads with different driving cycles and GPF combinations. The results showed that the GPF could significantly reduce particle emissions to meet the China 6 regulation. With further ash loading, the filtration efficiency increased above 99% and the effects on fuel consumption and backpressure were found to be limited, even with an ash loading of up to 50 g/l.

The urea NOx selective catalytic reduction (SCR) is an effective technique for the reduction of NOx emitted from diesel engines. Urea spray quality has significant effect on NOx conversion efficiency. The droplet diameter and velocity distribution of air-assisted and airless urea injection systems were obtained by particle dynamics analyzer (PDA) measurement under different spray injection flow rates. It was found that the atomization quality of air-assisted urea injection system is better than that of airless urea injection system. The penetration and spray cone angle were also investigated by high-speed photography. Especially the spray characteristics of air-assisted urea injection system were measured in the constant-volume-bomb by high-speed photography. The atomization and evaporation of airless urea injection systems were modeled using computational fluid dynamics (CFD) based on the experimental results. The numerical model was validated by the experimental results.