Thermoelectric Generators for the Integration into Automotive Exhaust Systems for Passenger Cars and Commercial Vehicles

Abstract

A special thermoelectric generator system design and the setup of a thermoelectric generator for the integration into the exhaust line of combustion engine-driven vehicles are described. A prototype setup for passenger cars and the effects on the measured power output are shown. Measurement results using this setup show the potential and the limitations of a setup based on thermoelectric modules commercially available today. In a second step, a short outline of the detailed mathematical modeling of the thermoelectric generator and simulation studies based on this model are presented. By this means, it can be shown by which measures an improvement of the system power output can be achieved-even if today's modules are used. Furthermore, simulation studies show how the exhaust gas conditions of diesel-and Otto-engines significantly affect the requirements on thermoelectric materials as well as the potential and the design of the thermoelectric generator. In a further step, the design and the setup of a thermoelectric generator for an application in a commercial vehicle are presented. This thermoelectric generator is designed to be integrated into the exhaust aftertreatment box of the vehicle. Experimental results with this setup are performed and presented. The results show that thermoelectric generators can become an interesting technology for exhaust waste heat recovery due to the fact that they comprise non-moving parts. However, the efficiency of the modules commercially available today is still far from what is required. Hence, modules made of new materials known from laboratory samples are urgently required. With regard to future CO 2 regulations, a large market opportunity for modules with a high efficiency can be expected.

Power and Fuel Economy of a Radial Automotive Thermoelectric Generator: Experimental and Numerical Studies

“…On the other hand, the heat absorbers of the ATEG may be circular tubes [7], straight fins [8][9][10][11], dimples [12], phase-change pipes [13], etc., and, to some extent, all of them increase the pressure upstream of the exhaust pipe. This back pressure alters the regular functioning of the engine and increases the fuel consumption.…”

Effects of Design Parameters on Fuel Economy and Output Power in an Automotive Thermoelectric Generator

“…Lan et al [15] analyzed this possibility in a large displacement engine. In heavy-duty vehicles, ATEGs can be installed in both exhaust and EGR systems [16,30], with a combined output power of 1 kW in a system fully integrated into the electronic controls of the vehicle. However, fuel savings were not reported.…”

Automotive Waste Heat Recovery by Thermoelectric Generator Technology

“…In automotive TEG, the type of heat exchangers used are mostly indirect, contact type with direct heat transfer between different medium such as gas and solid in the hot side and solid and liquid in the cold side of the system. According to the construction type and geometrical shape classification, the heat exchangers used are mostly either box type or tubular with extended surfaces such as fins or heat pipes depending upon the space available for the integration into the vehicle [10,11,21].…”

“…In a project partially funded by Swedish energy agency, with partners from Scania CV AB, Titan X, Eberspächer Exhaust Technology GmbH & Co. Germany, Swerea IVF, Gothenburg and KTH, Stockholm, a TEG system using Bi 2 Te 3 -based commercial modules has been designed, developed and tested in experimental hot gas test bench as well as in an actual engine exhaust [11]. The 224 modules which can be used up to 330°C are arranged in 14 modular TE units consist of hot exhaust gas and cooling water channels with counter crossflow arrangements.…”