真实发动机转速范围内缸内流动结构的PIV分析

In-cylinder PIV measurements have been made during the latter half of the intake stroke on a
plane between the inlet valves for a single cylinder optical engine operating at engine speeds of 750, 2000
and 3500 rpm. Mean vector fields for an area of 42 mm by 34 mm have been produced with vectors at
approximately 1 mm resolution. The vector fields show the development of the flow field in 1.6°, 2.4° and
3.2° steps for the three respective engine speeds.
Tumble ratios have been calculated from these vector fields which show that a change in the flow regime
occurs between 2000 and 3500 rpm. This is caused by one of rotating vortices becoming detached from the
descending piston at the highest engine speed. 德国LaVision PIV/PLIF粒子成像测速场仪 汽车发动机多参量测试系统 HighSpeedStar PIV相机