A method of matching the combustion chamber diameter based on spray characteristics for lateral swirl combustion system

To summarize a method of matching the combustion chamber diameter for lateral swirl combustion system (LSCS), at engine speeds of 1800 r/min and 2500 r/min, under 25%–100% loads and excess air coefficients (φ_a) of 1.2–2.0, the combustion and emission performance of LSCSs with different combustion chamber diameters was experimentally studied. Experimental results indicate that, with combustion chamber diameter of 88 mm, LSCS obtains the most favorable combustion performance, increasing the indicated thermal efficiency by 0.76%–4.03%. In addition, combustion chamber diameter affects the LSCS combustion performance more evidently under low load (25% load) and high excess air coefficient (φ_a of 2.0) conditions. Simulation research was performed under typical working conditions (at engine speed of 1800 r/min and 2500 r/min, under 50%–100% loads and φ_a of 1.2–2.0) to match the optimal combustion chamber diameter, and to study the corresponding spray characteristics. Simulation results show that, the optimal LSCS combustion chamber diameter and fuel spray penetration distance shows approximate liner relation. Therefore, the spray excess penetration coefficient τ is proposed, representing the interaction intensity between fuel spray and combustion chamber wall. For LSCS, when τ reaches its characteristic value of 1.5, the combustion chamber diameter matches well with the fuel spray penetration distance.