Abnormal sound of the engine of the Liugong 908D excavator
When the sound of the engine of a excavator is diagnosed, the abnormal parts of the sound are judged by the method of auscultation or acoustic vibration instrument, and then the parts and causes of the abnormal sound are determined in detail by the method of changing the working condition or the method of partially stopping the cylinder.
1 the method of auscultation, that is, a metal rod is placed in the relevant parts of the engine, and is judged according to the size, height, weight and nature of the sound. This method is used for the diagnosis of cylinder head, cylinder sleeve, bearing and gear system.
The 2 working condition change method. Some abnormal sound is obviously related to the working condition. At this time, the speed can be reduced from low to high, and the load is changed from small to large to judge the abnormal sound of the sound. This method is used to judge the sound anomaly caused by the fault of fuel and combustion system.
3 acoustic vibration instrument diagnosis method. Using the vibrator and noise meter to test the noise and vibration signal of the related parts, and to carry on the digital processing and analysis, and compare with the standard fault. This method is currently in the study, but it is the most promising and most accurate method.
The 4 part stop method. Due to abnormal sound, it is often caused by abnormal work of some cylinders. So when the cylinder is stopped working. If the noise is eliminated, it can be accurately diagnosed.
The 5 rocker shaft and bearing are abnormal sound caused by insufficient oil supply and burning. It is a rhythmic, continuous, continuous, clear "squeak, squeaky" sound produced by dry friction.
6 the noise caused by gear breaking is discontinuous "sand and sand" sound, showing regular "click, click" sound.
The 7 cylinder enters the foreign body. There is an irregular impact between the piston and the cylinder head, so the sound is disordered.
The 8 flywheel bolt loosens or the fan loosens. It causes the flywheel or fan to swing in operation, and the operation is unbalance, thus a dull, even "click, click" swinging sound appears.
9 the plunger spring of the oil pump is fractured.
10 the plunger of the oil pump is jammed. There is a "squeak" noise caused by poor motion and dry friction.
11 the metal friction between the loose parts of the connector and the collision of the rotating parts is a distinct sound, often accompanied by friction sparks.
12 the oil pressure valve is stuck, resulting in irregular oil flow, resulting in piping oscillation.
13 the spring of the oil outlet valve is broken. There will be a dull noise and broken sound, accompanied by black smoke and machine weakness.
