Design of a Thermoelectric Generator for Heavy-Duty Vehicles: Approach Based on WHVC and Real Driving Vehicle Boundary Conditions

Abstract

Fuel consumption and the CO2 emissions of heavy-duty vehicles are responsible for a great share of the road transport sector and substantial improvements are unlikely without further innovations. One part of this problem is that approximately 2=3 of the fuel’s chemical energy is lost in waste heat through the engine’s coolant and exhaust system. Heavy-duty vehicles are expected to continue using internal combustion engines; a waste heat recovery system provides a future potential to reduce the fuel consumption and the emissions. Thermoelectric Generators offer a low complexity solution. Based on the Seebeck effect, they convert thermal energy directly into electricity. Installed in the exhaust system of a vehicle, the system can supply the vehicles electrical system or charging the battery. Their benefits are low maintenance costs, relatively low system weight, small installation volume, and a competitive cost-benefit ratio. Recent research has focused on passenger cars but the potential for heavy-duty vehicles is high as well. Therefore, in this paper, the system development from potential analysis over design to experimental results, is presented for modern Euro VI heavy-duty vehicles with diesel and natural gas engines. The system integration is considered by analyzing installation positions in the exhaust aftertreatment system and its boundary conditions, such as available installation space and exhaust enthalpies for the most suitable positions. For this purpose, real road driving experimental data from long-haulage road circuit Stuttgart-Hamburg-Stuttgart and the representative World Harmonized Vehicle Cycle are presented as reference. Based on this data an approach for developing a thermoelectric generator system is investigated. The experimentally determined results of a hardware test and a simulation-based potential analysis are given for the vehicle interactions, the expected net electrical output power, and the reduced fuel consumption.