Thermoelectric Generators for Automotive Applications: A Concept Close to the Engine and High Power Density

Abstract

At the automotive development a major challenge is the achievement of the required reduction of CO2 emissions for ICEs. Therefore it is necessary to investigate all potential technologies to improve efficiency. Regardless of whether a conventional or hybrid vehicle concept is used, approximately 2/3 of the fuels chemical energy is lost as waste heat. Specifically, the waste heat of the exhaust gas provides through its high temperature level the highest potential. Therefore the technology of thermoelectric generators (TEG) is very promising for automotive application and under investigation for several years in the research field of alternative energy converter at the DLR Institute of Vehicle Concepts (DLR-FK). From the actual investigations for automotive application of TEG, an overview of the various potentials will be given under consideration of conventional and hybrid vehicles. The influences of the TEG to the vehicle overall system are shown. To get a maximum decrease of CO2 emissions under consideration of all overall system influences a holistic method for thermodynamic dimensioning was created at DLR-FK. The driving cycle WLTC is chosen as boundary condition. According to the results of this holistic method the TEG’s mass provides the biggest negative influence to the vehicle overall system. DLR’s highly integrated TEG-design will be presented and the simulative results represent up-to-date the world highest TEG power density for automotive application of >50W/kg and >130W/dm³. Figure 1 shows a functional research prototype that was constructed in such integrated TEG design. Furthermore a new vehicle integration concept for the TEG for conventional or hybrid vehicles will be shown.