汽油机进气歧管均匀性影响因素分析及结构参数优选

Analysis of Intake Manifold Uniformity and Selection of Preferred Structural Parameters for Gasoline Engine

基于一款增压三缸汽油机进气歧管,采用CFD分析方法研究了稳压腔-支气道过渡圆角、节气门安装角、进气歧管总管长度等参数对进气均匀性的影响。结果表明:增大稳压腔与气道之间过渡圆角,可以降低压损、增大相应支气道的进气流量;节气门布置的角度会对进气歧管内的流场产生影响,从而影响进气均匀性;节气门后总管长度对进气歧管流场分布有较大影响,总管长度越长,稳流距离越长,流场越顺畅,进气均匀性越好。最后采用以上规律结合布置空间优选进气歧管结构参数,使得进气均匀性指标达标,并在气道稳流试验台上得到了验证。

Based on the intake manifold of a 3-cylinder turbocharged gasoline engine,the CFD analysis method was used to study the influences of various parameters on uniformity such as the fillet radius between pressure chamber and branch intake port,throttle installation angle and the pipe length of intake manifold.The results show that the increase of fillet radius can reduce the pressure loss and increase the intake air flow rate of corresponding branch intake port.The throttle installation angle will influence the flow field in the intake manifold and thus affect the uniformity of intake air.The pipe length after the throttle has great influence on the distribution of intake manifold flow field.Longer length of manifold pipe can lead to longer pressure stabilizing distance,therefore smoother flow field and better intake uniformity.Finally,the above rules were combined with the layout space of the engine to select the preferred structural parameters of intake manifold so that the intake uniformity index reached the standard,which was verified on the airway steady flow test bench.