Two-Cylinder Turbocharged Gasoline Engine Concepts

摘要

The small envelope of a turbocharged two-cylinder engine makes it attractive for restrictive package situations, and when replacing a naturally aspirated four-cylinder engine, carbon footprint benefits can be expected from downsizing. In comparison to a turbocharged three cylinder engine of equal displacement, the two-cylinder as a parallel-twin needs a balancer shaft to compensate for first order oscillating mass forces. In consequence, it suffers from higher mechanical friction losses with according effects on fuel economy. In attempt to overcome the necessity of a balancer shaft, different arrangements of cylinders and firing intervals are investigated in a simulation study. The paper presents the effect of these variations on turbocharging, engine performance and efficiency, as well as vibrations.