本文分析了小型直喷式柴油机燃烧室的结构形状对气缸内气流运动的影响。探讨了通过优化燃烧室的结构设计，用以改善小型直喷式柴油机燃烧特性的机理。并据此设计了四角形、花瓣形和四角花瓣形等三种小型直喷式柴油机的新型燃烧室。 This paper analyzes the effect of the structure of small direct injection diesel engine combustion chamber on the air flow in the cylinder. The mechanism for improving the combustion characteristics of a small direct injection diesel engine by optimizing the structural design of the combustion chamber is discussed. Based on this, a new type of combustion chamber of three kinds of small direct injection diesel engines, such as quadrilateral, petal and petal, is designed.