进气道结构对混动发动机滚流和燃烧影响

Effect of Inlet Structure on Tumble Intensity and Combustion Process of Hybrid Gasoline-direct-injection Engine

摘要:

以某1.5L混合动力增压直喷汽油机为研究对象，利用稳态气道试验台架和三维仿真工具，研究了不同结构进气道对缸内稳态、瞬态滚流强度和燃烧性能的影响。研究中设计了4款不同滚流比进气道，对不同方案进行了稳态气道芯盒吹风试验，并将试验结果与三维仿真分析结果进行对比；利用三维仿真软件计算了不同进气时刻缸内瞬态滚流比、瞬态湍动能、缸内速度场、空燃比分布和火焰前锋面位置等。研究结果表明：更高的滚流比将改善缸内油气混合，提高点火时刻缸内平均湍动能，影响火焰传播速度，从而影响到缸内燃烧，进而影响汽油机的性能。

Abstract:

Based on a 1.5L hybrid turbocharged direct injection gasoline engine. The effects of different inlet structures on in-cylinder steady and transient tumble intensity and combustion performance were studied by using steady-state inlet test bench and 3D simulation tools. 4 different kinds of inlet were designed in this research. They were compared on a steady-state airway testing system with the simulation results. The in-cylinder transient tumble ratio， transient turbulent kinetic energy （TKE）， velocity distribution， air/fuel ratio and flame front of different inlet crank angle were calculated by simulation. The results showed that higher tumble ratio would improve the in-cylinder fuel air mixing and increase the average TKE at ignition phase， which affected the flame propagation velocity. Then it affected the in-cylinder combustion and performance of the GDI engine.