It is inevitable that a diesel engine will malfunction during long-term work. The usual solutions are to check, ask, listen, and watch. The most effective and direct method is to judge and solve the problem through sound, and can use the sound to judge and solve the problem. Some small faults are nipped in the bud by foresight and the occurrence of major faults is avoided. This is also a great advantage of using listening to troubleshoot problems instead of finding the fault by checking, looking and asking. In the previous article, we analyzed the first half of how to diagnose faults by listening to the sound of the excavator diesel engine. Today we will continue to look at the second half.
4. When the diesel engine is running, a heavy, dull knocking sound can be heard in the lower part of the diesel engine body. Especially when the diesel engine is working under high load, this sound becomes more obvious. This sound is caused by the crankshaft main bearing bush. Or caused by abnormal friction caused by the contact between the crankshaft main bearing and the main journal. The main reason is that the gap between the crankshaft main journal and the main bearing bush or crankshaft bearing is too large, causing friction between the main journal and the crankshaft main shaft bearing or main bearing bush. This heavy, dull knocking sound is caused by abnormal friction caused by uneven wear. When you hear this sound, you should stop the diesel engine immediately, because if you continue to operate the diesel engine without inspection and maintenance after this sound occurs, it is likely to cause “tile holding” and “shaft burning”. In order to avoid such a serious accident, the diesel engine should be stopped and checked to see if the main bearing bolts are loose. If not, the crankshaft, main shaft bearing or main bearing should be removed immediately, and professionals should measure it, calculate the gap value between them, and Compare with the specified data, and check the wear of the main shaft and tile shaft at the same time. Repair or replace if necessary.
5. When the diesel engine suddenly changes the load, a dull knocking sound can be heard near the engine body. This is mainly caused by the abnormal friction between the crankshaft connecting rod journal and the connecting rod bush. The main reason is that The gap between the connecting rod journal and the connecting rod bush is too large, causing local jump. The mechanism and maintenance detection method of producing this sound are exactly the same as those of the main shaft and main bearing bush.
6. At the front cover of the diesel engine, you can clearly hear a “howling” sound. This sound comes from the meshing gears inside the front cover. The gears of each meshing gear are excessively worn, causing the gear clearance to be too large, causing the engine to malfunction. The gears cannot enter the normal meshing state to produce this kind of sound. The solution is to open the front cover, check the gear meshing with lead sheets or paint, and make adjustments. If the gear gap is too large, new gears must be replaced in time.
7. The sound of objects colliding can be heard in the upper part of the cylinder. While the valve clearance is reduced, the impact sound also increases. The main reason for this sound is the collision between the valve and the piston, causing The main reason for this phenomenon is that the valve clearance is inappropriate, which causes the valve and the piston to collide with each other at high speed when the piston reaches top dead center. At this time, the diesel engine is unable to work and the load resistance of the machine is significantly reduced. The specific method to eliminate this fault is to raise the piston of each cylinder to the top dead center in order, press the valve downward, check whether there is any gap between the piston and the valve, and readjust the valve.
8. A mute and strong knocking sound can be heard along the entire length of the cylinder. This sound is more pronounced when the diesel engine is running at low speed or when the speed changes suddenly. The main cause of this phenomenon is excessive wear of the piston and the cylinder, causing the piston and cylinder to The gap is too large. When the piston moves up or down, the piston moves sideways inside the cylinder and swings. When in contact with the cylinder wall, the wear is aggravated and a dull friction sound is emitted. After this phenomenon occurs, professional technicians should be found to identify the cylinder liner and piston, and replace the piston or cylinder liner with a new one if necessary.
9. There is a sound similar to tapping an anvil with a small hammer all along the upper and lower parts of the cylinder. The main reason for this sound is that the gap between the piston ring and the ring groove is too large, causing the piston ring to collide with the piston when it runs up and down. The sound produced when struck is similar to tapping an anvil with a hammer. When this happens, stop the engine immediately and replace the piston rings with new ones.
The above is the next article on how to diagnose faults by listening to the sound of the excavator diesel engine. If you need to purchase related excavator accessories during the use and repair of your excavator, you can contact us. If you need to buy a second-hand excavator, you can also contact us.
Post time: Mar-28-2024