Development of CO<sub>2</sub> Emission Reduction Technology for Sport Motorcycles

<div class="section abstract"><div class="htmlview paragraph">With growing global concern about climate change, the challenge is to achieve carbon neutrality (CN) in motorcycles (MCs) as well, and various approaches are needed to achieve CN. For powertrains using internal combustion engines (ICEs), CN can be achieved by adopting CN fuels such as e-fuel and biofuel, but considering cost and supply, it is important to develop CO2 reduction technologies for ICEs. Compared with 4-wheel vehicles, MCs are required to be powerful, lightweight, compact and capable of travelling long distances, the CO2 reduction technologies that can be adopted tend to be a trade-off between dynamic performance and CO2 reduction, and a challenge is to achieve a high level of both requirements. We decided to focus on middle-class sports MCs, which require particularly high dynamic performance, and to develop CO2 reduction technologies. As a technology development target, CO2 emissions were set at 65 g/km in the worldwide-harmonized motorcycle test cycle (WMTC) class 3-2, while maintaining the dynamic performance required for sports MCs. The combination of technologies required to achieve the target was simulated and a concept was selected for technology demonstration. As a result, the downsizing concept with electrically assisted turbocharger (E-Turbo) was selected and CO2 emissions and dynamic performance were verified on a dynamometer using a prototype engine. This paper describes our approach to selecting the technologies based on these simulations and the demonstration results using the prototype engine.</div></div>