中文摘要：

在一台四气门光学发动机上，应用粒子图像测速技术（PIV）研究了四气门汽油机进气压缩过程缸内的滚流及其演化过程。研究结果表明：四气门汽油机缸内的滚流运动十分明显，滚流在进气行程的初始阶段就开始形成，经历了由弱到强再减弱的过程；单气门进气时，缸内滚流运动要比双气门进气时显著加强，气门中心面处所测得的滚流比绝对值要比汽缸中心面处大；在上止点后150°曲轴转角时，滚流比达到最大值。

英文摘要：

On a four-valve optical single -cylinder gasoline engine, PIV （particle image velocimetry） was used to study the evolvement of the tumble flow field produced by the intake - stroke and the compress - stroke on the two longitudinal sections in the cylinder, the one is the valve center plane and the other is the cylinder center plane; and the engine run in the two modes with single intake valve working and the double intake. The results show that tumble flow is significant, pro- duced at the stage of intake stroke, experiencing from weak to strong and from two vortex to a large scale tumble vortex ; the intensity of tumble vortex with single intake valve working stronger than the double intake, and tumble vortex in the valve center plane is more obviously than the cylinder center plane ; the absolute value of tumble ratio is bigger with single intake valve working than the double intake and increased slightly on valve center vertical plane than cylinder center vertical plane, the absolute value of tumble ratio is a peak value at 150°.