On-road instantaneous speed measurements on powered two-wheelers for exhaust emissions and fuel consumption evaluation

An experimental investigation on instantaneous speed measurements with instrumented motorcycles was performed considering three typical urban trips, divided in twelve sections according to different road classes. The main kinematic parameters obtained by processing experimental values are presented and compared with those referred to standard cycles, confirming that real world driving conditions are hardly reproduced by statutory cycles. Several applications of measured data are then analysed. Exhaust emission and fuel consumption factors were calculated for different motorcycle classes by applying the functions of Copert, Artemis and Progress models and the Artemis traffic situation approach, considering typical average speed levels and the experimental values. Results are then compared in order to highlight the differences between applied functions and methodologies. A selection of speed profiles was also performed in order to define the emissive behaviour of two wheelers on the chassis dynamometer: experimental emission and consumption factors for an Euro 3 scooter are related to calculated levels, while measured cold and hot exhaust emissions and fuel consumption of an Euro 2 moped are compared with the results obtained on standard and real world driving cycles, proving that the new speed patterns may be useful to define emissions and fuel consumption of these vehicles