Development and emissions performance analysis of local driving cycle for small-sized passenger cars in Nanjing, China

Abstract

Driving cycle is an important concept in quantifying vehicle emissions, and it is expected to adequately represent actual driving patterns of vehicle so that to obtain reliable estimates of vehicle emission. However, there is increasing concern about the gap between the actual driving conditions and standard driving cycles used for various vehicle certification and regulatory authorities. In this paper, the local driving cycle (LDC) for small-sized passenger cars in Nanjing is obtained by statistical combination of micro-trips by principle component analysis and clustering analysis method, then compared with the existing driving cycles of other cities in China. Significant differences have been observed between the driving cycles, emphasizing the need for the construction of LDCs for different cities. The developed LDC is simulated on chassis dynamometer to analyze the impact of speed and acceleration on emission rates for different pollutants. Meanwhile, the emission factors and rates of a small-sized passenger car in four driving patterns (acceleration, deceleration, cruising, idling) is obtained in LDC and other standard driving cycles for comparison purposes. The result reveals that the LDC is more appropriate for accurate estimation of vehicle exhaust emissions of small-sized passenger cars in Nanjing than standard driving cycles. Moreover, the presented result establishes a solid foundation for accurate performance evaluation of small-sized passenger cars in Nanjing and cities in the similar traffic situation.