Simulation and Optimisation of a Full Electric Hybrid Vehicle

One of the main driving forces in automotive R&D is the reduction of fuel consumption and emissions to meet nowadays ecological, social and legal requirements. Pure battery electric or fuel cell drive trains are highly favourable in that context; however, they still suffer from severe drawbacks regarding performance, range and durability. Therefore new concepts have to be investigated taking advantage of the existing technologies and their potential. The vehicle concept considered in this paper focuses on the development of a full electric hybrid vehicle comprising of conventional electric propulsion combined with a fuel cell as range extender. The advantage of such a system is that the fuel cell is used under rather constant load conditions, which is advantageous for its durability and efficiency.
The electric hybrid vehicle concept is based on a conventional electric Citroen Berlingo (Citroen Berlingo electrique) integrating a Solid Oxid Fuel Cell (SOFC) fuelled with bio-diesel. For determination of the requirements of the fuel cell and the energy management comprehensive simulations based on a longitudinal vehicle model have been performed. The simulation results of the electric drive train have been validated on components and system level. Based on this validated vehicle model the electric hybrid vehicle concept is developed. A fuel cell model is integrated and parameter variation is performed regarding the size of the fuel cell as well as the battery. Focusing on the vehicle range, driving and charging times different concepts are investigated. The paper gives a detailed description of the vehicle simulation, the parameter variation results, the validation process and the determined optimised vehicle concepts.