Optimisation of fuel efficiency for freeway vehicles

A novel idea for optimising the driving strategies based on the vehicle speed and acceleration commands is developed and proposed to improve the fuel efficiency of the next generation freeway vehicles. The decision-making problem of driving strategies is converted into a combinatorial optimisation problem by dividing the route into a certain amount of consecutive sections, and the optimal speed and acceleration commands to be recommended to the vehicles are determined. Traffic condition in the freeway is defined as the traffic operating at the free-flow speed that is not inhibited by the presence of other vehicles, for example, off-peak times or sparsely populated areas. A two-stage process is used for optimisation. In stage one, the ADVISOR software is used to perform offline calculation of fuel consumption in divided sections for reducing time cost of the online optimisation. The lookup table of consumed fuel and time of the vehicle with different operation conditions is constructed for online process. In stage two, the MAX-MIN ant system algorithm is used to optimise the fuel-efficient driving strategies. A real route is considered as the object for experimental study. The results show that, based on the proposed fuel-efficient driving strategy, fuel consumption could be significantly improved while compared with the aggressive driving strategies.