Development of a Gasoline Particulate Filter for China 6(b) Emission Standards

New emissions regulations of light-duty vehicles (China 6) will be implemented in China from July 1, 2020. This standard includes two stages, China 6a and China 6(b), in which the PM limits of 4.5 mg/km and 3.0 mg/km are introduced respectively; the PN limit is set to be 6×10¹¹ #/km for both stages. The WLTC testing cycle will be implemented in China 6 regulation as well.

In this study a light-duty vehicle satisfying China 6(b) emission standards was developed by improving the engine raw emissions, optimizing the calibration and adding a coated GPF to the after-treatment system. The impacts of ash content and consumption of engine oil and the fast ash accumulation to vehicle emissions and backpressure were analyzed through dynamometer testing. The vehicle after-treatment system was then designed and developed to meet China 6(b) emission standards. The characteristics of soot accumulated through mimicking routine driving under cold environments were tested. The critical conditions of passive regeneration and the controlling strategies of active regenerations of GPF were also studied.