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How to Judge the Working State of Diesel Generator Set by Sound

Oct. 08, 2018

Diesel generator set belongs to mechanical equipment and is prone to malfunction during long working hours. The common method of judging fault is listening, looking, checking, among which, the most effective and direct method is to judge by the sound of generator, and can eliminate the small fault by sound, in order to avoid the occurrence of major fault. Below shows you how to judge the working state of diesel generator set from the sound.

How to Judge the Working State of Diesel Generator Set by Sound.jpg


1. When the diesel engine running at low speed (idle speed) of the diesel generator st, the metal tapping sound of blah, blah can be heard obviously by the valve cover. The sound was caused by an impact between the valve and the rocker arm, mainly because the valve gap was too large. The valve clearance is too large or too small, the diesel engine can not work properly. The gap between the valve and the valve is too large, the displacement between the rocker arm and the valve is too large, and the impact force caused by the contact is also greater, so that the metal knock sound is issued. This sound often occurs after long hours of work, so the valve clearance should be readjusted for every 300 hours or so of work.


2. When the diesel engine of diesel generator sets suddenly drops from high speed to low speed, the sound of when, when can be heard clearly in the upper part of the cylinder. This is one of the common problems with diesel engines. This main reason is that the gap between the connecting rod bushings is too large, and a lateral dynamic imbalance caused by the sudden change in the speed of the machine causes the piston pin to swing to the left and the right while rotating in the connecting rod bushing. The sound of a piston pin striking the bushing of a connecting rod. In order to avoid more trouble and cause unnecessary waste and economic loss, the piston pin and connecting rod bushing should be replaced in time to ensure that the diesel engine can work normally and effectively.


3. The diesel engine of a diesel generator set can hear a heavy, dull knock at the lower part of the diesel engine block. This noise becomes more pronounced especially when the diesel engine is working at high load. The sound is caused by abnormal friction between the crankshaft spindle bush or crankshaft spindle bearing and the main journal, mainly because the gap between the crankshaft spindle bearing and the spindle bush or crankshaft bearing is too large. This heavy, blunt knock, which results in uneven wear between the spindle neck and the crankshaft spindle bearing or bearing, resulting in abnormal friction. The work of the diesel generator set should be stopped immediately after the sound is heard, because if the sound is heard, the diesel generator set will continue to work without inspection and maintenance, and the phenomenon of "holding the tile" and "burning the shaft" is likely to occur. In order to avoid such a serious accident, the work should be stopped immediately to see if the spindle tile bolt is loose. If the crankshaft and spindle bearing or bearing should not be removed immediately, measured by a professional, the clearance between them shall be calculated and compared with the prescribed data, and the wear of the spindle and tile shaft shall be checked at the same time, Repair or replacement shall be given if necessary.



4. In the upper part of the cylinder, the engine can clearly hear a clear sound of the piston beating the cylinder block, which is often referred to as the "knock cylinder." The root cause of this failure is that the injection advance angle of the diesel engine is too small. As we all know, the fuel supply advance angle of diesel engine is one of the main technical data of diesel engine. Whether the fuel supply advance angle is correct or not will directly affect whether the diesel engine can work normally and whether the engine can provide normal power. Affect the working condition of the whole machine. In order to make the mixture formation and combustion process can be carried out normally, the diesel engine must have a certain injection advance angle, the injection advance angle is too small, and the air injected into the cylinder forms combustible gas combustion, which leads to unstable combustion. In the upward stage of the piston, the lateral deviation collides with the cylinder wall, and the knock on the cylinder body produces the sound of the cylinder knocking.


5. The diesel engine can hear a blunt-mute sound near the engine block while changing the load suddenly. This mainly comes from 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, resulting in local runout. The mechanism of producing this sound and the method of maintenance detection are identical to those of spindle and spindle bush, so it is not introduced in detail here.


6. In the front cover of the diesel engine, a kind of "howling" sound can be clearly heard. This sound comes from the meshing gear inside the front cover, and the gear wear in each part of the meshing gear is excessive, which causes the clearance of the gear to be too large, so that the gear cannot enter the normal meshing state to produce this sound. The exclusion method is to open the front cover. Check gear meshing with lead sheet or paint and adjust. If gear clearance is too large, new gear must be replaced in time.


7. On the full length of the cylinder of a diesel engine, the mute sound can be heard, especially when the engine runs at a low speed or changes in speed. This phenomenon is mainly caused by excessive wear between the piston and the cylinder, which makes the gap between the piston and the cylinder too large. When the piston is up or down, the piston moves sideways inside the cylinder and oscillates, and when in contact with the cylinder wall, the wear is aggravated. Make the mute sound of friction. After this phenomenon, a professional technician should be found to identify the cylinder liner and piston, and replace the new piston or cylinder liner if necessary.


8. The sound of hammering anvil is similar to the sound of the diesel engine cylinder along the diesel generator set. The main reason for this sound is that the gap between the piston ring and the ring groove is too large, which makes the piston ring strike with the piston when it is running up and down, thus producing a sound similar to that of tapping the anvil with a small hammer. Once this happens, the engine should stop working and replace the new piston ring.


9. The sound of an object colliding can be heard at the top of the cylinder. At the same time as the sound reduces the valve gap, the impact sound also increases. The main reason for this sound of generator set is the collision between the valve and the piston. The main reason for this phenomenon is that the valve gap is not suitable. When the valve is running up to the top of the piston, the valve and the piston have a strong impact at high speed. At this time, the diesel engine is unable to work, and the anti-load ability of the machinery is obviously decreased. The concrete method of eliminating this kind of malfunction is to raise the piston of each cylinder to the top and stop point in order, press the valve down, check the gap between the piston and valve, and readjust the valve.




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