Validation Test on a Light Duty Vehicle Equipped with a GDI Engine to Meet China 6b RDE Regulation for PN

China 6 (CN6) emission legislation for light duty vehicles was published in 2016, which introduced real driving emissions (RDE) requirements for new type-approval content. Nitrogen oxides (NOx) and particle number (PN) of RDE test are required to be monitored and reported from July 2020 in CN6a phase, fulfilled from July 2023 in CN6b phase. To meet the PN limitation of CN6 RDE, the optimized engine combustion and advanced emission control system like gasoline particle filter (GPF) are encouraged. Compared to traditional vehicle platform emission compliance which could be done in lab, much more vehicle development and validation efforts are expected on the open road for RDE compliance. High cost and complexity are expected to conduct a complete validation test matrix covering all the RDE critical boundary conditions on the open road. To investigate a logical RDE validation process from lab to open road covering various critical boundary conditions like soaking temperature, altitude and driving dynamics, and evaluate the PN RDE compliance risk on a CN6a vehicle, a group of surrogate RDE cycle lab emission tests and RDE tests on the open road were conducted on a CN6a vehicle equipped with a 1.5L TGDI engine. A developed surrogate RDE lab cycle for saving efforts on road and a complete RDE validation process for RDE compliance from lab to open road was introduced in this study. Test results showed that considering extreme conditions, such as -7°C ambient temperature, 2300m altitude and aggressive driving as well, the PN emission of the tested vehicle could fulfill the CN6b RDE PN limitations with GPF.