Inverted Brayton Cycle Employment for a Highly Downsized Turbocharged Gasoline Engine

The study presented in this paper aims to evaluate the performance of a new conceptual combined power system composed of a turbocharged engine and an inverted Brayton cycle (IBC). A validated 1D model of a downsized SI engine has been built in GT-power as the baseline model to quantify the performance improvement due to introducing the inverted Brayton cycle. The results show that a system performance improvement caused by adopting IBC is expected depended on the engine load, IBC turbomachinery efficiency and the bottoming expansion ratio. The maximum thermal efficiency of the combined system is achieved when both the wastegates of turbocharger and IBC turbines are closed, which is up to 6.15 percent point.