Analysis of an automotive thermoelectric generator coupled to an electric exhaust heater to reduce NOx emissions in a Diesel-powered Euro VI Heavy Duty vehicle

This study presents a new approach to minimize the amount of NOx emitted by diesel engines of Heavy-Duty Vehicles during low engine regimes and low gases temperature conditions. We propose the addition of an electric Exhaust Gas Heater (EGH) to make the SCR system inject the urea solution at low engine regimes. The second part of this study focuses on the viability to use an Automotive Thermoelectric Generator (ATEG) to generate the energy required by the EGH and thus avoiding the need to consume electrical energy from the vehicle’s system. This EGHATEG system is designed to be energetically closed, so there is no extra consumption of fuel. Experimental results show that NOx emissions reduce up to 80% when an EGH is added to a standard diesel-powered Euro VI Heavy Duty truck configuration. Simulations show that an ATEG installed downstream of the aftertreatment system can produce the energy required by the EGH. This system can improve SCR efficiency up to 55% during low engine regimes.

Analysis of an automotive thermoelectric generator on a gasoline engine

This study determined the heat, flow, and electrical power values of and automotive thermoelectric generation system integrated in the exhaust system of an internal combustion gasoline engine. The combustion analyses of the engine integrated with and without automotive thermoelectric generation were carried out. The 20 thermoelectric modules were placed on the rectangular structure which was made of the aluminum 6061 material. The thermoelectric modules were electrically connected to each other in series. The gasoline engine was operated at full load at 1250, 1750, and 2250 rpm, and the electrical energy generated by the automotive thermoelectric generation system was calculated. At the same time, the heat and flow analyses of the automotive thermoelectric generation system were performed using the ANSYS FLUENT commercial software.

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

Recent developments of high performance thermoelectric (TE) materials have increased the interest of using this technology to directly convert waste heat into electricity. In the automotive sector, many automotive thermoelectric generators (ATEGs) designs use TE modules (TEMs) with high hot side temperatures to cope with high engine load regimes. Here, we develop a new concept of a radial ATEG that is specifically designed to work with low temperature TEMs, which enables the use of Pb-free modules and reduces the thermal stress of the device. A prototype is built and tested at different regimes in an engine test bench. A numerical model of the ATEG is developed and validated. The consequences of modifying (1) the exchange area between the heat absorber and the exhaust gases and (2) the effective figure of merit of TEMs on the electrical output power and fuel economy are investigated by means of simulations. Results indicate that the maximum fuel economy (1.3%) is not attained at the point of maximum output power (228 W). In terms of fuel economy, the back pressure at the exhaust penalizes high mass flow regimes. We use a dimensionless parameter to analyze the potential of the ATEG for reducing fuel consumption.