一、引言内燃机活塞裙部形状有圆锥形,鼓形,桶形等,这些形状的测量,常规的方法是用分度盘、千分表和三座标测量机或圆度仪,利用这些方法得到的是离散点的座标位置而无法知道其实际型线方程,给引进活塞外形曲线分析工作带来了困难。本文通过对国外引进的某一活塞裙部型线的测量,用最小二乘法原理,通过计算机处理,回归成多项式,得到了活塞裙部型 I. INTRODUCTION The internal combustion engine piston skirt has the shape of conical, drum, barrel, etc. The measurement of these shapes, the conventional method is to use dial, dial indicator and coordinate measuring machine or roundness meter, using these methods Get the coordinates of the discrete points can not know the actual line equation, the introduction of piston profile curve analysis has brought difficulties. In this paper, the introduction of a foreign country measured the skirt skirt line, using the principle of least squares, through computer processing, regression polynomial, the piston skirt type