Novel optimization strategy to improve fuel economy for heavy-duty trucks

Many fuel consumption improvements for heavy-duty diesel engines have been achieved in the area of control and calibration. Few have addressed methods of improving fuel consumption during highway cruising. Since cruise control is activated most of the time during long trips, it should be seen as a viable option for improving fuel economy. If environmental changes and resulting engine load changes can be anticipated, the cruise control operation can be optimized with respect to fuel efficiency. We propose three cruise control reference-shaping strategies to improve engine efficiency and reduce truck on-highway cruising fuel consumption. These strategies would use GPS and computerized terrain maps to predict upcoming engine load changes in order to improve fuel economy. Assumptions are identified and appropriate constraints imposed on the fuel consumption, vehicle speed and nominal mission time. The algorithms of the three shaping strategies predict torque in order to prevent engine lug back and improve fuel economy. The algorithms were tested using a Matlab simulation on five routes. On average over the routes, fuel improvement of 1.77% was achieved.