Abstract: The real driving emission test （RDE） was carried out with four gasoline vehicles to investigated the influence of cold start, the dynamic parameters and two different calculation methods to real driving emission， and the pollutant emission was calculated with the CO2 moving average window method and the new Euro 6 method. The results show that the deviation of the influence of cold start on CO and NOx emission is within 10%, and cold start has a greater influence on urban PN emission for vehicles without gasoline particulate filter (GPF), with a maximum difference is up to 32.25%, so it is necessary to pay more attention on the calibration of new vehicles. Relative position acceleration (RPA) is positively correlated with particle number (PN) emission, but has no obviously correlation with CO and NOx. The v*apos,95 (the 95th percentile of the value of velocity times positive  acceleration) is positively correlated with CO and PN emissions, as opposed to NOx emission, and the positive correlation coefficient is greater than negative correlation coefficient. For the same valid test, the calculation result with newly Euro 6 is larger than that with the CO2 moving average window method, the newly method can more truly reflect the vehicle pollutant emission in the RDE test.

Key words: light-duty gasoline vehicle , real driving emission (RDE) , cold start ,  dynamic parameters , gasoline particulate filter (GPF)