多缸发动机缸压采集时压缩上止点的确定

Compression TDC Determination of In-cylinder Pressure Acquisition for Multi-cylinder Engine

为了分析发动机的缸内燃烧状况及发动机各缸工作的一致性和循环变动,需要开发一套多缸发动机缸压数据采集系统,而压缩上止点定位的准确性是影响放热率等计算准确性的重要因素。介绍了利用光电编码器作为触发信号和角标信号进行多缸发动机缸压采集过程中压缩上止点定位的一种新方法,并且对在缸压采集过程中动态上止点的偏移现象进行了修正,同时对在缸压采集试验中遇到的压缩上止点偏移问题提出了妥善的解决方法,为之后数据分析的准确性提供了保证。

In order to analyze the in-cylinder combustion and the consistency between cylinders and the cycle-to-cycle variations, an in-cylinder pressure data acquisition system of multi-cylinder engine is necessary and the accurate determination of compression TDC position is one of the important factors that affect the calculation of heat release rate. A new method of determining the compression TDC in the data acquisition system with the photoelectric rotary encoder as a trigger and angle signal was introduced and the dynamic TDC offset of acquainting was modified. The proper solution to the compression TDC offset problems encountered in the cylinder pressure acquisition experiments was proposed, which can guarantee the accuracy of the subsequent data analysis.