Modeling and optimization of a biogas fueled reactivity controlled compression ignition engine

Reactivity controlled compression ignition (RCCI) engines are a relatively new and promising method with high efficiency and low emission values. In RCCI engines, the combustion inside the cylinder is controlled with different reactivation degree fuels that are injected into the intake and into the cylinder. Thus, high performance and low exhaust emission are obtained with this strategy. In this study, biogas fueled RCCI engine was modeled using one-dimensional code. The engine model was validated by experimental data. The influence of biogas injection into the intake as a low reactivity fuel was evaluated with diesel as a high reactivity fuel. Accordingly, the effects of lambda, engine speed, compression ratio, intake pressure, injection timing of the RCCI engine were investigated on combustion and engine performance. The potential of biogas usage in an engine as a renewable resource has been examined. The intake and exhaust valve timings were optimized using a genetic algorithm to achieve minimum brake specific fuel consumption (BSFC). According to the parametric and optimization studies, optimum engine operating parameters were determined. The engine power and torque were increased by 15,1%, while the BSFC decreased by 11,3% with the engine optimum parameters.