Abstract

In order to evaluate fuel consumption and the tailpipe emissions of a vehicle, standard driving cycles are used to prescribe vehicle driving conditions such as speed, gear shifts, fluid temperature etc. The new European Driving Cycle (NEDC) has been widely used as a driving cycle for emissions and fuel consumption while the Federal Test Procedure 75 (FTP-75) mode is used in the United States. In South Korea, the NEDC is applied for emission certification and the FTP-75 mode is used for the fuel consumption of a vehicle powered by a diesel engine. Because these driving cycles contain a mix of static phase (cruising and idle) and transient phase (acceleration and deceleration), they need to be translted to static engine operation conditions so that optimization is possible using an engine dynamometer for each representative engine operation condition. This study set up two models to convert vehicle driving conditions to engine operation conditions based on the work which the engine should produce to follow the driving cycle, and based on the representative vehicle speeds of the NEDC. The accuracy of each model was compared with actual vehicle test results on a chassis dynamometer, and the characteristics of each model were analyzed.