In the last few years, several studies have proved the benefits of exploiting information about the road topography ahead of the vehicle to adapt vehicle cruising for fuel consumption reduction. Recent technologies have brought on-board more road information enabling the optimization of the driving profile for fuel economy improvement.
In the present paper, a cruise controller able to lowering vehicle fuel consumption taking into account the characteristics of the road the vehicle is traveling through is presented. The velocity profile is obtained by minimizing via discrete dynamic programming the energy spent to move the vehicle. In order to further enhance vehicle fuel efficiency, also the gear shifting schedule is optimized, allowing to avoid useless gear shifts and choose the most suitable gear to match current road load and keeping the engine in its maximum efficiency range. Despite the optimality of the solution provided, dynamic programming entails high computational time. Moreover, it is unlikely to have the a-priori knowledge of the entire route. To deal with these issues, the optimization problem is solved over a receding horizon of finite length following a model predictive scheme, balancing the sub-optimality of the solution and the computational burden.
The controller is assessed by means of simulations for a passenger car in several urban and highway driving scenarios, taking into account for fuel consumption reduction and changes in travel time.