Research on the relationship between test cycles and real-driving emissions 2019-01-0753
In China, the emission regulation and fuel consumption regulation of LDV are two parallel regulations, with different requirements especially test cycles, which are not tend to be unified in a short period of time. China had already introduced WLTC cycle into the emission regulation and is now revising the fuel consumption regulation, where the newly developed China Light-duty Test Cycle (CLTC) is one of the potential candidates to replace NEDC as test cycle. In view of this inconformity and the fact that strong connections exist between test cycles and real-driving emissions (RDE), this research mainly focused on the two latest test cycles in China (WLTC and CLTC), studying the relationship between different test cycles and RDE. A series of tests were carried out on gasoline vehicles with different technical types – PFI naturally aspirated, DI naturally aspirated and DI supercharged under CLTC cycle, WLTC cycle and RDE procedure. The difference on a-v distributions, frequency distributions of accelerations, emissions and fuel consumptions between test cycles and RDE tests were studied. It revealed that the CLTC cycle had wider and more comprehensive a-v coverage, more similar acceleration distributions, and more close assessment on fuel consumptions and emissions during RDE test comparing to WLTC cycle, which shows a better or a closer characterization potential of lab test to real-driving under the actual traffic circumstance of China.