Enigneering Creativity Award: Fluid Mechaical Optimization of Two-Stroke Engines

这项流体力学研究的目的是通过检测发动机内部的精确流动，从而提高进入空气和燃料的混合物，从而提高内燃机的输出和燃油经济性。更好的混合意味着更充分地燃烧燃料，这也意味着更安全的排放。目前涉及发动机流动流体力学的技术在获取有关流体湍流的重要信息方面尤其有限。密歇根州立大学开发了一项新技术，该技术涉及一束激光，该激光束被分割成发动机中相交线的网格。有了这项新技术，各种各样的发动机诊断和流体力学将被执行。利用新技术得到的网格区域的速度梯度，可以确定应变率和涡量。内部发动机设计将受益于使用这些数量，因为它可以优化气缸内燃烧气体的清除，并最大限度地减少与燃烧的电荷的混合。这项新技术为空气和燃料的燃烧前混合提供了更好的可能性。

The objective of this research in fluid mechanics is to increase the output and fuel economy of an internal combustion (IC) engine by examining the exact flow inside an engine thereby enhancing the mixture of the incoming air and fuel. Better mixing means more complete burning of the fuel which also implies safer emissions. Current techniques involving the fluid mechanics of engine flows are limited particularly in capturing important information regrading fluid turbulence. A new technique has been developed at Michigan State University involving a laser beam which is divided to form a grid of intersecting lines in the engine. With this new technique a wide variety of engine diagnostics and fluid mechanics will be performed. Using the velocity gradient in the region of the grid obtained by the new techniques, the strain rates and vorticity quantities will be determined. Internal engine design would benefit using these quantities since it would be possible to optimize scavenging of the cylinder of burnt gases and minimize mixing with the burnt charge. The new technique offers improved possibilities for pre-combustion mixing of air and fuel.