This paper deals with an analysis of the potential of the Rankine cycle as an additional power generation process, which uses the waste heat of a car engine. A review of different heat recovery technologies leads to the identification of the steam process as a favorable solution for automotive applications.
Two basic configurations (exhaust gas only; exhaust gas plus coolant) are selected from numerous illustrated Rankine cycle layouts for a detailed evaluation of heat recovery based on a four-cylinder internal combustion engine (ICE). Furthermore, the impact of different working fluids is studied. A parametric analysis of the efficiency of two selected systems is accomplished with the Dymola simulation tool, followed by a direct comparison between both configurations for different engine technologies and vehicle speeds.
Finally, test bench measurements of the applied engine coupled with a heat recovery device are carried out. It can be demonstrated that waste heat recovery can produce an additional power output of about 10% at typical highway cruising speeds.
