Experimental investigations on emission characteristics of heavy-duty hybrid electric vehicles

Abstract

The emission characteristics under different operating modes (engine mode and hybrid mode) and different test cycles (C-WTVC and CHTC) of a heavy-duty hybrid electric dump truck was investigated on the chassis dynamometer. The emission performance was recorded using Portable Emissions Measurement System (PEMS) and analyzed combined with the characteristic parameters of the test conditions. It is found that the NOx emission under hybrid mode is higher than that under engine mode, while the CO emission under hybrid mode is lower than engine mode. Under engine mode, the NOx emission of CHTC is higher than that of C-WTVC. However, under hybrid mode, the NOx emission of CHTC is lower than C-WTVC. Analysis of CO emission characteristics shows that under engine mode, CO emission is concentrated at low speed and small load condition, while under hybrid mode, CO emission is concentrated at high speed and large load condition.