Parametric study of the effects of the design factors on the performance of a heat recovery system obtained from an exhaust gas in a gasoline engine

Abstract

A parametric study was conducted to determine the optimum operating conditions of a waste heat recovery system obtained from the exhaust gas. An analysis of the Rankine cycle was also performed with respect to the changes in the evaporation pressure and the mass flow rate of the working fluid, which have a significant influence on the performance of a heat recovery system. The analysis conditions in this study were selected on the basis of the mass production of an actual waste heat recovery system attached to a real engine exhaust manifold, and the energy flow obtained from gasoline engines was analysed using the first and second laws of thermodynamics. A model for analysing the heat exchanger was also developed using the experimental data on heat transfer between the actual exhaust gas and the working fluid. Based on this model, a cycle analysis of the waste heat recovery system was conducted through one-dimensional simulation. The optimum operating conditions and waste heat recovery system performance were determined from the analytical results. In addition, the potential of the heat recovery system was evaluated by investigating the brake specific fuel consumption of a gasoline engine equipped with a waste heat recovery system.