一台ZL20型装载机采用4125型柴油机。作业过程中,突然感觉柴油机无力,冒黑烟,消音器发出“突突”的响声。用“断缸法”逐缸检查,当Ⅳ缸断油时,排气冒黑烟的现象减弱,依次校对4个缸的喷油器及喷油泵的压力后,故障依旧。打开缸盖,检查Ⅳ缸燃烧室的工作情况时,发现缸套上、下止点处的销轴方向有高温烧蚀的积瘤槽,进一步作检查时发现,Ⅳ缸活塞销已断裂。 A ZL20 loader with 4125 diesel engine. During the operation, suddenly feeling diesel weakness, black smoke, muffler issued a “sudden” sound. With the “broken cylinder method” by the cylinder check, when Ⅳ cylinder off the oil, exhaust black smoke phenomenon weakened, followed by proofing 4 cylinder fuel injector and injection pump pressure, the fault still. Open the cylinder head, check the working condition of the IV cylinder combustion chamber, found cylinder liner, the bottom dead center pin at the high temperature ablation of the plot of tumor trenches, further inspection revealed that Ⅳ cylinder piston pin has broken.