Correlation of Gasoline Vehicle Emissions between Simple Loaded Mode and New Vehicle Emission Certification Mode

The emissions of 50 in-use gasoline light-duty vehicles were tested under simple loaded mode conditions,including transient loaded mode(IM195),short transient loaded mode(IG195) and steady-state loaded mode (ASM),and the new vehicle emission certification mode(NEDC) condition according to the national emission standards.The results show that IM195 has the best correlation to NEDC.The correlation factor R~2 of CO,HC and NO can reach 0.7010,0.7271 and 0.6609 respectively.The second is IG195,which R~2 of CO,HC and NO are(0.5138),(0.4846) and(0.6245.) And ASM including two mode conditions has the worst correlation.The R~2 of CO,HC and NO under 5025 mode condition are (0.4109),(0.4481) and(0.5449).Under 2540 mode condition,the R~2 of CO,HC and NO are(0.3644),(0.3395) and(0.4578).Meanwhile,different pollutants under the same simple loaded mode condition have different correlative coefficients compared with the results under the NEDC mode.The main reasons include different warmup conditions,test modes,measuring principles of the analytical instruments and control precision of the chassis dynamometer.