某四缸柴油机EGR管插入深度对EGR均匀性的影响

针对某带EGR的直列四缸柴油机,为了分析EGR管插入进气总管中的深度对四个气缸EGR率均匀性的影响,建立了该进气歧管内CO_2与新鲜空气流动混合的三维瞬态计算模型,并进行数值计算。计算并分析了三种不同EGR管插入深度对气体在进气歧管中的混合特性。研究结果表明:插入进气总管中的EGR支管越深1缸、2缸的EGR率越高,3缸、4缸中EGR率越小;方案2中EGR支管插入深度为35 mm时,四个缸的平均EGR率偏差值最低,符合工程设计要求。

Influence of Insertion Depth of EGR Pipe on EGR Uniformity of a Four-cylinder Diesel Engine

To analyze the influence of the depth of the EGR pipe inserted into the intake manifold on the uniformity of the EGR rate of the four-cylinder diesel engine, a three-dimensional transient calculation model of CO2 mixing with fresh air in the intake manifold was established and numerical calculation was carried out. The mixing characteristics of the gas in the intake manifold were calculated and analyzed for three depth of the EGR pipe inserted into the intake manifold. The results show that, the deeper the EGR pipe inserted into the intake manifold, the higher the EGR rate of cylinder-1 and cylinder-2, the lower the EGR rate in cylinder-3 and cylinder-4. When the insertion depth of the EGR branch pipe is 35 mm in case 2, the average EGR rate deviation of the four outlets is the lowest, which meets the engineering design requirements.