Experimental Study on the Impact of Lubricant Ash on CN6 After-Treatment System Performance of GDI Vehicle 2021-01-0586
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. With the ash accumulation in the CGPF, the filtration efficiency of CGPF for the particulate number (PN) continuously increased and finally could maintain a high efficiency up to 99.7%. The ash accumulation had a reasonable influence on gas light-off temperature of CGPF (less than 15°C), and had little influence on the maximum conversion efficiency. The increase of ash content in CGPF would increase the CGPF pressure drop and decrease engine torque, which have influenced by about 8.9kPa and 3.5%, but the influence on fuel consumption was not obvious in the external characteristic test. The ash was mainly deposited at the end, especially in the central area of CGPF and the height of 60g ash could reach 41.7mm, which accounted for about 41% of the total length of the carrier. In summary, the after-treatment system can well meet the endurance requirements of 200kkm in CN6 regulation.