Review of Waste Energy Resource in Vehicle Engine Exhaust

Energy recovery from vehicle engine exhaust has attracted considerable interest recently. Key parameters associated with the engine exhaust, including temperature, mass flow rate, maximum extractable energy, and optimum location for energy extraction all factor strongly into the materials research and device design for waste heat recovery. This review paper compiles available data in literature on the vehicle engine exhaust resources for several different vehicles, and under various operational conditions. Three vehicles types, namely, mid-size sedans, light duty trucks, and heavy duty trucks, have been considered, and the driving cycles including Federal Test Procedure (FTP) series, Highway Fuel Economy Test (HFET) and New European Driving cycle (NEDC) are considered in this review. The results show the average temperatures at highway driving cycle and city driving cycle remain in the ∼500–650°C and ∼200–400 °C range, respectively. The mass flow rate varies significantly with vehicle size. The available thermal power calculated based on the collected data is 3–10 kW.