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Integrating Thermo-Electric Generators into Vehicle Exhaust Systems

February 18, 2016 by Jeff Shepard

Vacuumschmelze GmbH and Co. KG (VAC) will take part in the three-year thermoHEUSLER2 project – a continuation of the thermoHEUSLER research and development project in which VAC was previously involved. The joint project receives funding from the German Ministry for Economic Affairs and Energy under the "Effizienzsteigerung Fahrzeugantriebe" (Efficiency Improvement for Automotive Drives) initiative. Its objective is to integrate a thermoelectric generator into a vehicle exhaust system, enabling part of the waste heat in the exhaust emissions to be converted directly into electricity, thereby helping to power the on-board generator and reduce the vehicle's fuel consumption and carbon emissions.

In the first phase of the project, researchers at the University of Mainz will be investigating the possibilities of increasing the efficiency of thermoelectric semi-Heusler alloys. VAC’s task will then be to improve the production process of these new alloys and develop a cost-effective and feasible process for manufacturing ultra-small geometries; for the purpose intended, these thermo-electric materials must be produced in extremely compact blocks approximately 1 to 2 mm square. Avenues explored in this research will include near-net-shape sintering procedures and a variety of cutting processes.

Other organizations involved in the joint project include the Fraunhofer Institute of Physical Measurement Techniques (IPM) in Freiburg and the companies Isabellenhütte, Faurecia Siemens and Audi. In the final phase of the process, the completed thermoelectrical generator will be installed in an Audi A6 2.0 TFSI.

VAC has already conducted research into manufacturing processes for thermo-electric semi-Heusler alloys in this project’s predecessor, thermoHEUSLER (October 2011 to December 2013). VAC developed a special powder metallurgy process, now patented, that enables powdered metals to be sintered to form solid parts without the need for high pressure. As a result, semi-Heusler alloys can now be produced in a process similar to that used for rare-earth permanent magnets.