The sport motorcycles continue to provide riders with the riding pleasure by the excellent potential of mobility performance brought by lightweight, compactness and high-performance powertrains.
However, we are in a situation where we need to make efforts to reduce CO2 emission as much as possible on a global scale, and we also need to make serious efforts to reduce CO2 emission for sport motorcycles. The challenge for sport motorcycles from this perspective is a drastic improvement in fuel efficiency while maintaining the "vehicle dynamic performance", "drivability performance" and "to meet the latest exhaust emission regulation", and Yamaha has been proceeding the several feasibility studies aiming for realizing this challenge as advanced development.
In one of the feasibility studies, "Downsizing Concept with boosted DI technology," we developed a research motorcycle equipped with a powertrain that achieved a specific output of 156kW / L (133kW / 0.85L) on a sport motorcycle. As a result of the development, we were able to obtain 92g / km-CO2 in WMTC which is equivalent to about 30% improvement in fuel efficiency compared to the best FE model in 2017, while keeping excellent drivability.
In this report, we will introduce the development of this powertrain "Internal Combustion Engine (ICE) with turbocharger (TC)" for motorcycle especially following two (2) viewpoints.
- 1
To balance engine performance, emissions, and fuel economy.
- 2
Drivability development to obtain linear throttle response or the required drivability.