Feasibility Study Of The WLTP Used For Chinese Road Light-duty Vehicles

This paper studies the development process of test cycle and test procedure of WLTP. The key steps and the technical methods of the development process are summarized. The adaptability of WLTP test procedure is researched by selecting 10 small displacement, low power China’s independent brand vehicles. The improvement and the new idea of the WLTP are summarized on the basis of the national emission standards V. The emission differences of the sample cars are studied in WLTP and national emission standards V, the sample cars include multipoint injection gasoline cars, direct injection gasoline cars and diesel cars. This paper selects the hybrid and pure electric vehicles to study the charge and discharge conditions under the WLTP and NEDC cycles. The difference of the cycles eigenvalue of WLTP, China and the United States are comparatively analyzed. By the eigenvalue analysis, combining with China country road conditions and vehicle usage, as well as referencing the experience of the United States, the weight coefficient of each stage cycles of WLTP are obtained. One American car and one European car are selected to study the emissions differences among the WLTP, NEDC and FTP-75. With the reference of the Europe VI, the national emission standards VI(draft) and EPA Tier III emission limits, the WLTP limits are given.The test results show that the development process of test cycle and test procedure of WLTP is scientific and rigorous. The project has completed the test condition and made a successful work with the combination of the states parties own different requirements. China’s independent brand vehicles can track WLTP cycle basically, some small-displacement and low power vehicles have certain difficulty and severely exceed the emission standard. The CO emission of the gasoline cars and the NOx and the PM emission of the diesel cars are more serious. Compared with the national emission standards V, the WLTP has a lot of improvements, at the same time, the WLTP puts forward many new test concepts. The emissions of the sample vehicles are increased in various degrees under the WLTP. The CO emissions of the gasoline cars and the NOx emissions of the diesel cars are more serious. According to the mileage weighted calculation in different stages of the fuel consumption, compared the WLTP with the NEDC, the fuel consumption have certain differences. For hybrid and pure electric vehicles, the specific power consumption of the WLTP is higher than the NEDC. The city driving cycle of the WLTP which consists of the low and medium speed stage is correlated with the China city driving cycle, the high speed stage of the WLTP has a good correlation on the China high speed driving cycle.