The real driving emission characteristics of light-duty diesel vehicle at various altitudes

High altitude shows a great influence on vehicle emissions because of lower pressure and shortage of oxygen concentrations. In addition, type approval test of light duty vehicle is usually carried out below the elevation of 1000 m. In order to address the effect of high altitude on vehicle emissions, real driving emission (RDE) test procedure has been introduced in China VI emission regulation. Thus, the effects of altitude on the emissions from a China IV certificated light-duty diesel vehicle under real road driving conditions were investigated in this work. Research results show that CO emissions increased with the elevated altitude. At the altitude of 2990 m, the CO emissions increased by 209% in comparison with that of near sea level in whole test cycle. At specific test modes, CO emissions follow the sequence of urban > rural > motorway. Both PN and NOx emissions also rose with altitude while NOx emissions at 2990 m showed a decreasing tendency. In addition, different tendency between high altitudes and relative low altitudes was observed under specific test modes, which was probably related to the function of after-treatment device.