Design of Variable Geometry Waste Heat Recovery Turbine for High Efficiency Internal Combustion Engine

Abstract

This study was carried out for a 1.25L Zetec-SE DOHC engine model but its application is generic to gasoline engine (light-duty engine) applications. An ORC model with a radial turbine sub-model is implemented in a light-duty gasoline I.C engine model, to evaluate the impact of the ORC with VGT on the engine fuel consumption, net power output and finally the ORC system efficiency as compared to ORC with FGT. The results showed that VGT can improve ORC system efficiency and net power output by an unweighted point of 5.6% and 3.07kW respectively at partial to high load conditions while benefits are even higher at the lower loads therefore making it an attractive technology given its ability to recover low-grade heat and the possibility to be implemented in decentralized lower-capacity power plants