Effects of combustion chamber diameter on comprehensive performance of the lateral swirl combustion system under various conditions

To determine how the combustion chamber diameter affects the comprehensive performance of the lateral swirl combustion system (LSCS), experiment and simulation research were carried out under various working conditions. Specifically, simulated turbocharging single-cylinder diesel engine was used to test the combustion and emission performance of LSCSs with combustion chamber diameters in the range of 88–100 mm. Simulation was then conducted to reveal the influence mechanisms of combustion chamber diameter on the fuel/air mixing characteristics of LSCS. Experimental results show that, LSCS with combustion chamber diameter of 88 mm showed the most favorable combustion performance under various loads and excess air coefficients. In addition, the influence of the combustion chamber diameter on LSCS combustion performance varied with working conditions. As engine load decreased or the excess air coefficient increased, the influence of the combustion chamber diameter on LSCS performance became more evident. Simulation results indicated that the excessive combustion chamber diameter weakened the wall-flow-guided effect and interferential interactions in LSCS, thereby deteriorating the fuel/air mixing quality. This was particularly obvious under low load or high excess air coefficient conditions, where the interaction between fuel spray and the wall-flow-guided structure of combustion chamber wall was insufficient due to the weakened fuel spray penetration ability.