Exploring light-duty internal combustion engine boosting and exhaust compounding strategies

Abstract

A set of two-cylinder engine concepts utilizing a supercharger and piston-compounding or turbine-compounding were compared to a supercharged, non-compounded engine modeled with a consistent methodology. The goals of this simulation were to utilize energy that otherwise would be bypassed around the turbine side of a turbocharger and redirect it to the crankshaft. Following previous modeling work on a different piston-compounded engine, the gains in performance and efficiency for these concepts were thoroughly analyzed to provide insight into the magnitudes and responsible mechanisms. It was found that the second expansion process from exhaust-compounding was able to significantly improve engine performance at moderate to high loads, but the level of benefits and low-load performance were highly dependent on the compounding technique.