Influence of driving cycles on powered two-wheelers emissions, fuel consumption and cold start behavior

A wide investigation on powered two-wheelers (PTWs) is presented, aiming at the analysis of the influence of the driving characteristics on PTWs exhaust emissions and fuel consumption, a deeper comprehension of the engine and after-treatment system behavior within the cold start transient and the evaluation of cold start additional emissions for different two-wheelers classes. The study was developed with reference to an European context focusing on Euro 3 motorcycles and Euro 2 mopeds. An experimental investigation on instantaneous speed measurements was carried out with instrumented motorcycles, considering typical urban trips in the city of Genoa. A selection of speed profiles was then performed by processing experimental values. In a following phase, emissions and fuel consumption of selected motorcycles and mopeds were measured on the chassis dynamometer, considering tests in cold and hot operating conditions on standard, real world driving cycles and experimental speed profiles, allowing to study the influence of different speed patterns on exhaust emissions. Finally, a wide statistical analysis was developed in order to identify the most influencing kinematic parameters on fuel consumption and hot emissions, while analysis of cold start transient was conducted to assess the influence of vehicle characteristics and kinematic parameters of tested driving cycles on cold start duration, travelled length and extra-emissions. The main results of the wide investigation program are presented and discussed, with reference to Euro 3 scooters and Euro 2 mopeds with similar engine and after-treatment system characteristics, thus allowing a comparison between the different vehicle types.