Electricity from exhausts — development of thermoelectric generators for use in vehicles

Abstract

In the course of increasing demands to reduce fuel consumption and CO2 emissions of vehicles with combustion engines, we will have to make use of hitherto unused energy flows. It is well known that as much as a third of input energy is converted to exhaust heat, so it is clear that work needs to be done to increase the utilisation of this energy. Through the application of thermoelectric generators (TEG), in the future a proportion of the exergy carried by the exhaust gases that would previously have been lost will be recovered as electrical energy. The German Aerospace Center (DLR) has developed TEG for use in vehicles for doing this, and, resulting from collaboration with the BMW Group, 200 W of electrical power in a test vehicle was achieved in a demonstration. Given the use of future materials, performances of up to 600 W can be expected, yielding a usage potential of 5 %. The current research focus is aimed at improving the manufacturing technique with a view to future standard production applications.