Commercial vehicles contribute to the majority of freight transportation in the United States. They are also significant fuel consumers, with over 23% of fuel used in transportation in the United States. The gas price volatility and increasingly stringent regulation on greenhouse-gas emissions have driven manufacturers to adopt new fuel-efficient technologies. Among others, an advanced transmission control strategy, which can provide tangible improvement with low incremental cost.
In the commercial sector, individual drivers have little or no interest in vehicle fuel economy, contrary to fleet owners. Aggressive driving behavior can greatly increase the real-world vehicle fuel consumption. However, the effectiveness of transmission calibration to match the shift strategy to the driving characteristics is still a challenge. In this article, a new adaptive shift strategy is proposed, which uses the driver score as a proxy to match the driving characteristics in real time and contribute to a better fuel economy.
Drivability objective is also included in the optimization through an estimated torque reserve and it is subsequently evaluated via a newly developed metric. The adaptive shift strategy can significantly improve the fuel economy for an aggressive driving style. It also provides the fleet owner with a means to set a balance between fuel economy and drivability.
