A highly efficient energy converter for a hybrid vehicle concept - focused on the linear generator of the next generation

The linear generators (LG) are integrated into a system called free-piston linear generator (FPLG). Such a generator is capable of converting chemical energy into electrical energy by using a combustion process. An FPLG can be used as an alternative energy converter for hybrid cars. One of the possibilities to reduce the fuel consumption of a vehicle significantly is to optimize the efficiency of the linear generator. The focus of this publication is on the first and second generations of integrated linear generators. The first part of this publication explains the function and the characteristics of free-piston linear generators. Then, the surrounding system and its effect on the FPLG and the linear generator are illustrated. This is important in order to understand the adaptation of linear generators into the system. Afterwards, the calculation process of the linear generator of the first generation is outlined. Following the presentation of the calculated results, a comparison between the calculation and the measured results of the developed linear generator is presented. The next chapter then focuses on the efficiency measurement´s outcome. After considering the first generation linear generator, the need for a change in concept is explained. The new concept, which is based on the results of the efficiency measurements made with an industrial LG, will be presented afterwards. The following chapter provides a comparison of the linear generator from the first and the second generation. The paper concludes with a description of the current FPLG situation.