When Perkins diesel generator is operating, the noise is mainly from mechanical friction sound of
diesel engine. Experienced technicians can judge the hidden trouble of a part
of diesel engine from the sound. We can judge fault from following sound:
1.When Perkins diesel
engine is running at low speed (idle speed), the metal knocking sound of
"bar da, bar da" can be heard beside the valve cover.
This sound is caused by
the impact between the valve and the rocker arm. The main reason is that the valve
clearance is too large. Valve clearance is one of the main technical indexes of
diesel engine. If the valve clearance is too large or too small, the diesel
engine will not work normally. Too large valve clearance causes the
displacement between the rocker arm and the valve to be too large, and the
impact force generated by the contact is also large, so we can hear the metal
knocking sound of "bar da, bar da". This kind of sound often appears
after the engine works for a long time, so the valve clearance should be
readjusted every 300h or so.
2.When diesel generator
set suddenly drops to low speed from high speed, the impact sound of
"Dang, Dang" can be heard on the upper part of the diesel engine
cylinder.
The reason is mainly
oversize clearance between piston pin and connecting rod bush and suddenly
changing speed of engine, which causes the piston pin to swing to the left and
right while rotating in the connecting rod bush, and causes the piston pin to
hit the connecting rod bush and make a sound.
To reduce the occurrence
of larger faults and avoid unnecessary waste and economic loss, we should
replace the piston pin and connecting rod bushing in time so as to make the
diesel engine operation normally.
3.A heavy, dull knocking
sound can be heard at the underpart of the diesel engine body.
This kind of noise is
caused by the abnormal friction between main bearing shell of crankshaft or the
contact between the main bearing of crankshaft and the main journal.
The main reason is that
the clearance between main journal of the crankshaft and the main bearing shell
or the crankshaft bearing is too large, which results in the uneven wear
between the main journal and the crankshaft main bearing or the main bearing, and
resulting in the abnormal sound.
If we hear this kind of
sound, should shut down diesel generator set. Because if it continues to work
in this case, and we do not inspect, it is likely to occur "holding
tile" and "burning shaft" phenomenon. In order to reduce this
fault, we should shut down the diesel genset, then check whether main bearing
bolt is loosen. If not, we should remove the crankshaft and main shaft bearing
or main bearing bush, calculate the clearance between them by relevant
personnel measurement. And check the wear of the main shaft and the bush shaft
at the same time, and repair or replace them if necessary.
4.When diesel engine is
running, crystal knocking sound of piston striking cylinder block can be heard
clearly at the upper part of the cylinder.
The root cause of this
kind of fault is that the injection advance angle of diesel engine is too
small.
As we 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 the normal operation of diesel engine, and directly affects
whether the engine can provide normal power and the working condition of the
whole generator set.
In order to make mixture
formation and combustion process normal, diesel engine needs fuel injection
advance angle. When the injection advance angle is too small, the air injected
into the cylinder will form combustible gas combustion, which will lead to
combustion instability. In the upward phase of the piston, it will generate
lateral deviation and collide with the cylinder wall to knock the cylinder
block. So it generates crystal knocking sound.
5. At the front cover of
diesel engine, a kind of "howl" sound can be heard clearly.
The reason is the
meshing gear in the front cover, which is excessively worn, the clearance
between the gears is too large, so that the gears can not enter the normal
meshing state. The solution is that open the front cover, check the gear
engagement with lead sheet or paint, and adjust it. If the gear clearance is
too large, the gear shall be replaced in time.
After diesel generator
has been used for a long time, it is inevitable that there will be abnormal
sound. As long as we can find the abnormal sound in time and judge fault
according to the abnormal sound, we will resolve it.
If you still have
question or need to purchase Perkins generator, contact us by
sales@dieselgeneratortech.com.
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