The main purpose of this paper will be to investigate if a small snowmobile gasoline Direct Injected (DI) two-stroke engine has the potential to be adapted for two other types of applications: as a range extender (REX) for electric vehicles and for a motorcycle application.
For the REX application, the main requested specifications (NVH, lightweight, compactness, minimum production cost and easy maintenance), correspond well to the main features of DI 2-stroke engines. The potential of a modified production engine operating in part load ultra-low NOx Controlled Auto Ignition (CAI) to meet the Euro 6 emissions standards on the NEDC cycle has already been demonstrated in a previous paper. In the first part of this new paper, we will investigate which solutions can be used to maintain this potential with even stricter legislations based on Euro 6d, WLTP cycle and Real Driving Emissions (RDE).
In the second part of this paper, the feasibility of using the same production DI 2-stroke base engine for a motorcycle application will be studied. To meet the future Euro 4 and 5 motorcycle emissions standards on the new WMTC driving cycle, new combustion strategies have to be implemented. They are based on the use of CAI at part load and of the control of the air-fuel ratio at higher load combined with a 3-way catalyst aftertreatment technology.
The encouraging results achieved show that such small DI 2-stroke engine could be a very attractive candidate for a low emissions motorcycle application as well as for a range extender application in an electric vehicle.