工程机械液压系统中的液压油在使用一段时间之后会逐渐老化、变质,一些外来物质也会造成液压油的污染,因此液压油在使用一定时期后必须更换。确定液压油更换时机的方法基本上有以下三种:定期、试验和经验更换法。在应用经验更换法确定换油时机时,现场评定液压油的质量是经常要做的工作。下面介绍几种液压油质量的现场评定方法:1.观察液压油的颜色 The hydraulic oil in the hydraulic system of the construction machinery will gradually deteriorate and deteriorate after being used for a period of time. Some foreign substances will also cause the contamination of the hydraulic oil. Therefore, the hydraulic oil must be replaced after being used for a certain period of time. There are basically three ways to determine the timing of hydraulic oil change: regular, test, and experience replacement methods. In the application of experience replacement method to determine the timing of oil change, on-site assessment of the quality of hydraulic oil is often done. Here are some methods of on-site evaluation of hydraulic oil quality: 1. Observe the color of hydraulic oil