Driving strategy for minimal energy consumption of an ultra-energy-efficient vehicle in Shell Eco-marathon competition

Abstract

The paper focuses on the different driving strategies (driving cycles) for minimisation of the energy consumption of an ultra-energy-efficient electric vehicle developed by students for Shell Eco-marathon competition. The vehicle runs on hydrogen fuel and completes a set track with a 1420 m length and zero vertical deviation which is used for the 2019 European edition of the contest. A dynamic simulation model of the vehicle is developed taking into account vehicle resistance forces. A simplified model of the propulsion system is also described and used in the simulation. The propulsion system consists of a hydrogen fuel cell with a 1 kW rated power output, electric motors, electric converters, motor controllers and transmission. Furthermore, a strategy overview is proposed by which the vehicle complies with all necessary strategy limitations deriving from the competition rules. The various driving strategies, that comply with the competition average speed and differ from one another by the number of motors and transmission ratio, are simulated. The optimisation is done by changing the maximal and the minimal no-load speeds of the vehicle. A comparison of the energy usage is therefore conducted based on these strategies and the optimal one is chosen. In conclusion, additional driving strategies are proposed, in case more vehicle manoeuvrability or simpler driving style are desired during the race.