Today VEP Diesel Parts service tells you ways to gauge fault by the abnormal sound of Perkins diesel. Hope it’s helpful to you.
When Perkins diesel generator is working, the noise is especially from the mechanical friction sound of diesel. Experienced technicians can judge the hidden trouble of a neighborhood of diesel from the sound. we will judge fault from the following sound:
1.When Perkins diesel is running at low speed (idle speed), the metal knocking sound of “bar da, bar da” is often heard beside the valve cover.
This sound is caused by the impact between the valve and therefore the valve rocker. the most reason is that the valve clearance is just too large. Valve clearance is one of the most technical indexes of diesel. If the valve clearance is just too large or too small, the diesel won’t work normally. overlarge valve clearance causes the displacement between the valve rocker and therefore the valve to be overlarge, and therefore the impact force generated by the contact is additionally large, so we will hear the metal knocking sound of “bar da, bar da”. this type of sound often appears after the engine works for an extended time, therefore the valve clearance should be readjusted every 300h approximately.
2.When the diesel generator set suddenly drops to low speed from high speed, the impact sound of “Dang, Dang” is often heard on the upper part of the diesel cylinder.
The reason is the especially oversize clearance between piston pin and rod bush and suddenly changing the speed of the engine, which causes the piston pin to swing to the left and right while rotating within the rod bush, and causes the piston pin to hit the rod bush and make a sound.
To reduce the occurrence of larger faults and avoid unnecessary waste and economic loss, we should always replace the piston pin and rod bushing in time so on make the diesel operation normally.
3.A heavy, the dull knocking sound is often heard at the underpart of the diesel body.
This kind of noise is caused by the abnormal friction between the main bearing shell of the crankshaft or the contact between the most bearing of the crankshaft and therefore the main journal.
The main reason is that the clearance between the main journal of the crankshaft and therefore the main bearing shell or the crankshaft bearing is just too large, which ends up within the uneven wear between the most journal and therefore the crankshaft main bearing or the most bearing and leading to the abnormal sound.
If we hear this type of sound, should pack up the diesel generator set. Because if it continues to figure during this case, and that we don’t inspect, it’s likely to occur “holding tile” and “burning shaft” phenomenon. so as to scale back this fault, we should always pack up the diesel Genset, then check whether the main bearing bolt is loosened. If not, we should always remove the crankshaft and main shaft bearing or main bearing bush, calculate the clearance between them by relevant personnel measurement. And check the wear and tear of the most shaft and therefore the bush shaft at an equivalent time, and repair or replace them if necessary.
4.When diesel is running, crystal knocking sound of piston striking engine block is often heard clearly at the upper a part of the cylinder.
The root explanation for this type of fault is that the injection advance angle of diesel is just too small.
As we know, the fuel supply advance angle of diesel is one of the most technical data of diesel. Whether the fuel supply advance angle is correct or not will directly affect the traditional operation of diesel, and directly affects whether the engine can provide normal power and therefore the working condition of the entire generator set.
In order to form mixture formation and combustion process normal, diesel needs a fuel injection system advance angle. When the injection advance angle is just too small, the air injected into the cylinder will form combustible gas combustion, which can cause combustion instability. within the upward phase of the piston, it’ll generate lateral deviation and hit the cylinder wall to knock the engine block. So it generates a crystal knocking sound.
5.At the front cover of diesel, a sort of “howl” sound is often heard clearly.
The reason is that the meshing gear within the front cover, which is excessively worn, the clearance between the gears is just too large, in order that the gears can’t enter the traditional meshing state. the answer is that open the front cover, check the gear engagement with sheet music or paint, and adjust it. If the gear clearance is just too large, the gear shall get replaced in time.
After a diesel generator has been used for an extended time, it’s inevitable that there’ll be abnormal sound. As long as we will find the abnormal sound in time and judge fault consistent with the abnormal sound, we’ll resolve it.