Combined effect of chamber geometry and compression ratio on the combustion process in a methanol-enriched rotary engine

The combustion process within a methanol-enriched gasoline rotary engine is being studied to understand how the geometry of the combustion chamber and the ratio of methanol blending influence it. The rotary engine model was developed, combined with a streamlined methanol-gasoline reaction kinetics model, to emulate the effects of diverse recess geometric configurations on combustion. The research findings indicate that even minor adjustments to the recess volume can significantly enhance in-cylinder turbulence levels during the intake stroke. Notably, reducing the recess length achieved higher turbulent dissipation at ignition, thereby promoting the propagation of the initial flame kernel. Under high compression ratio conditions, optimizing the recess geometric parameters effectively improved combustion efficiency and reduced emissions. The CR9.5W configuration is recommended for adoption, as it significantly lowered unburned hydrocarbon and NOx emissions while enhancing combustion efficiency. This work provides a potential direction for performance enhancement in rotary engines. However, the reduction in the size of the recess restricts heat and mass exchange between the anterior and posterior sections of the combustion chamber. This phenomenon potentially causes significant fluctuations in the combustion process and increases the risk of knock.