Testing cycles for heavy-duty vehicles are an important topic for authorities, manufacturers, fleet owners, etc. in order to assess exhaust gas emissions and fuel consumption. A new methodology was developed to derive representative testing cycles from velocity versus time driving information. During the development, the work was focussed on city-buses, but the methodology can be applied to heavy-duty vehicles in general.
The testing cycles are ‘distance-based’, meaning they impose goal speeds at each location. This implies that during acceleration phases, the accelerator-pedal - and gear lever in case of manual transmission - can be operated in a realistic way. The techniques for deriving this kind of testing cycle are proposed. Results of on-board emission and fuel consumption measurements employing these testing cycles are presented for two 19 tons, 160kW city buses, equipped with respectively a diesel and a CNG (stoechiometric) engine, and a 10 tons 112 kW diesel delivery truck.