Assessment of the Effect of Road Load on Energy Consumption and Exhaust Emissions of a Hybrid Vehicle in an Urban Road Driving Cycle—Comparison of Road and Chassis Dynamometer Tests

Abstract

Differences between the results obtained in laboratory and road tests of vehicles depend on a number of factors. Among the most important of these are driving cycle and road load. These parameters also affect the hybrid drive control, including the combustion engine operation or driving in electric mode. In most studies, tests carried out on chassis dynamometers concern type approval cycles (NEDC—New European Driving Cycle, WLTC—World-wide harmonized Light duty Test Cycle, FTP— Federal Test Procedure), which differ from real on-road tests. Consequently, the different driving cycles do not allow for results similar to those obtained during on-road driving, especially as the actual cycles on the road are unrepeatable. It is also important to determine the effect of the motion resistance function adopted for chassis dynamometer tests on exhaust emissions and fuel consumption. For this purpose, the authors tested a hybrid car under road and laboratory conditions for the same driving cycle. The analysis was conducted for an example urban road cycle in Rzeszow (URRC). The purpose of the study was to determine the differences in the results of gaseous emissions (THC, CO, CO2, NOx) and fuel consumption (energy) of a hybrid car under road conditions, with the results of tests conducted on a chassis dynamometer, for the same cycle and three functions of resistance.