Comparative evaluation of eight legislated driving schedules in terms of cycle metrics and emissions from a diesel-powered turbocharged van

Abstract

The present work compares, on a fundamental basis, the performance and emissions of a diesel-engined large van running on eight legislated driving cycles, namely the European NEDC, the U.S. FTP-75, HFET, US06, LA-92 and NYCC, the Japanese JC08 and the Worldwide WLTC 3-2. It aims to identify differences and similarities between various influential driving cycles valid in the world, and correlate important cycle metrics with vehicle exhaust emissions. The results derive from a computational code based on an engine mapping approach, with experimentally derived correction coefficients applied to account for transient discrepancies; the code is coupled to a comprehensive vehicle model. Soot as well as nitrogen monoxide are the examined pollutants. Only the driving cycle schedule is under investigation in this work, and not the whole test procedure, in order to identify vehicle speed (transient) effects of the individual cycles only. The recently developed WLTC 3-2 is the cycle with a very broad and at the same time dense coverage of the vehicle’s/engine’s operating activity, being thus particularly representative of ‘average’ real-world driving. Even broader is the distribution of the US06, whereas particularly thin and narrow that of the modal NEDC. It is also revealed that the more transient cycles, e.g. the NYCC or the US06, are also the ones with the highest amount of engine-out pollutant emissions and energy consumption. Relative positive acceleration and stops per km are found to correlate very well with energy and fuel consumption and all emitted pollutants.