进气道关键结构参数对缸内充量分层模拟研究

Stratified Simulation of In-cylinder Charge by Key Structure Parameters of Intake Port

通过进气充量分层,实现缸内分层燃烧,将进气道的进气截面等分为进气道右上区(A区)、进气道左上区(B区)、进气道左下区(C区)、进气道右下区(D区)4个区域,分别通入4种不同示踪气体,研究进气在缸内的运动及分布规律。研究表明:D区进气贡献率最大,占27.3%,B区进气贡献率最小为22.4%;且在压缩上止点附近B区可以形成较为规则的环形分布,但在ω燃烧室靠近皮带轮一侧有较多的气体。通过对进气道3个关键结构参数,进气道偏转角、螺旋室高度、进气道偏心距研究得出结论:进气道偏转角为15°时,缸内涡流强度最大,在进气道偏心距为-2 mm时,缸内涡流强度最小;通过对进气道结构参数进行优化,在进气道偏转为15°时,B区进气浓度梯度差最大。

Through stratified intake charge,stratified combustion in the cylinder is realized,and the intake cross section of the intake port is equally divided into the upper right zone(A zone),the upper left zone(B zone),the lower left zone(C zone)and the lower right zone(D zone)of the intake port.Four different tracer gases are passed in to study the movement and distribution of intake air in the cylinder.The research shows that the contribution rate of the intake air in D zone is the largest,accounting for 27.3%,and the contribution rate of the intake air in B zone is the smallest,22.4%;and the B zone can form a more regular annular distribution near the top dead center of compression,but there is more gas near the pulley side in theωcombustion chamber.By studying the three key structural parameters of the intake port,the intake port deflection angle,the height of the spiral chamber,and the eccentricity of the intake port,it can be obtained that when the intake port deflection angle is 15°,the in-cylinder vortex intensity is the largest,and when the eccentricity is-2 mm,the in-cylinder vortex intensity is the smallest.By optimizing the structural parameters of the intake port,when the intake port deflection is 15°,the difference in the intake concentration gradient in B zone is the largest.