应用高速纹影法对汽油机燃烧过程的研究

根据光学纹影法的基本原理和高速摄影技术,在可视化发动机台架上搭建了一套反射式纹影光路系统,使其能够较清晰准确地记录燃料初期蓝焰的扩散过程。通过对比,纹影图像比直接摄影图像能更早地观察到火焰的产生,火焰轮廓更大,能够反应火焰的变化形态。试验将此系统应用在汽油机燃烧过程的研究中,并分析了空燃比和负荷时汽油机火焰传播速度及火焰形态的影响。结果表明:在理论空燃比附近,随着混合气变浓,着火始点靠前,火焰传播速度加快,火焰的表面皱折变大;负荷的提高使得燃烧更加充分,着火提前,火焰传播速度提高,火焰皱折增大。

Research on the Combustion Process of Gasoline Engine by High-Speed Schlieren Method

Based on the principle of schlieren method and high-speed photography technology, a set of reflect-type schlieren system was built on one optical engine test bench. The diffusion process of blue flame at the initial stage of combustion could be recorded clearly by this system. Compared with the images taken by direct photography, the earlier generation of flame, the broader flame contour and the transformation of flame configuration could be observed from schlieren results. This system was then used to study the com bustion process of gasoline engine. The effect of air/fuel ratio and load on the velocity of flame propagation and the flame configuration were analyzed. The results reveal that the addition of the mixture concentration near to stoichiometric ratio and the boost of the load makes the combustion more sufficient, the start of com bustion earlier, the velocity of flame propagation faster and the wrinkle face of flame greater.