Delivering Fuel Economy with Motorcycle Oil Additive Technology 2017-32-0008

Sustainability trends and reduced fuel consumption as a value proposition to end users have led to an ever-increasing focus on fuel efficiency in the personal mobility segment. This is evident in the development of smaller and lighter engine hardware with optimized combustion systems as well as the lowering of engine oil viscosity grades and formulation of additives with improved friction properties. Due to the unique challenges of lubricating motorcycle engines, the development of fuel efficient motorcycle engine oil presents several technical dilemmas. The reduction of oil viscosity gives rise to durability concerns particularly in such high temperature and high speed operating conditions, while the formulation of additives with lower friction properties may affect clutch friction that is necessary for a manual motorcycle. Hence, this study was embarked on to develop a 4T motorcycle engine oil formulation that can achieve fuel economy credits without compromising clutch friction and durability.

The development began with a fundamental understanding of the surface and viscometric effects from each major component of the formulation (including within the additive system, the base stocks and the formulation viscometrics) and across each lubrication regime (i.e. from the boundary to hydrodynamic regime). This was followed by the optimization of these components to maximize fuel economy credits. Finally, a prototype was developed through a balanced combination of these components to provide a well-rounded friction reduction across the entire lubrication regime, as benchmarked against an SAE 10W-30 OEM Genuine Oil. The preliminary friction screening tools used in this study were bench tests (i.e. SRV, HFRR and MTM) run under carefully selected test conditions, with the fuel economy data subsequently validated through a chassis dynamometer test based on the World Motorcycle Test Cycle in an actual motorcycle. In addition, to assess the hypothesis that engine friction can be reduced without compromising clutch friction and durability, the prototype was put through the JASO T903:2016 and modified FZG gear pitting tests. The results of this extensive fundamental understanding and performance evaluation activity will be presented in detail in this paper.