This article lists several
methods for quickly diagnosing diesel engine output power shortages. Why is the
diesel engine power insufficient? The power of diesel engines is the same as
other internal combustion engines and is affected by many factors.
1. Look at
the charcoal and check the condition
The carbon deposit in the exhaust
port of the diesel generator is black and gray, and the surface is covered with a
layer of hoarfrost. The carbon deposit is extremely thin, indicating that the
diesel engine is in good working condition. The colour of the carbon deposit is
black and not wet, indicating that the diesel engine burns slightly oil. The
deposit of the exhaust port of a certain cylinder is thicker, indicating that
the injector of the cylinder is not working properly or the cylinder sealing
performance is deteriorated, and repair or replacement should be performed.
Individual exhaust ports are wet or organic oil flow marks, indicating that the
cylinder oil should be repaired. The carbon deposits in the exhaust ports of
each cylinder are thicker and darker in colour, mostly due to the working
temperature being too low, or the fuel injection is too late, and the
post-combustion phenomenon is serious.
2. Look up
and down smoke, check the wear
When the diesel engine is
working, open the oil port cover, if a thick smoke emerges from the oil port
cover, it is said to smoke. The smoke is serious, indicating that the piston,
cylinder liner, piston ring and other components are seriously worn. Open the
valve cover, such as a trace of blue or white smoke from the root of the valve
(valve face), said to smoke. The smoke is serious, indicating that the valve
and valve seat are severely worn or ablated, or that the valve clearance is too
small or even no gap.
3. Look at
the water temperature, check the cooling
If the water temperature of the
cooling system is too high (more than 100 °C) when the diesel engine is
working, it may indicate that the scale of the cooling water chamber of the
diesel engine is too thick or the components of the cooling system (thermoster,
water pump, fan, etc.) are inefficient or fail.
4. Look at
the gas distribution, check the phase.
After long-term operation of the
diesel engine, the timing gear, cam surface, follower column and tappet will
wear, so that the opening and closing time of the intake and exhaust valves
will be postponed and deviate from the optimal valve timing, so that the
charging efficiency is reduced and the diesel engine power is reduced. .
Therefore, it is necessary to regularly check the phase of the diesel engine's
valve, and if it does not meet the requirements, it should be adjusted in time.
5. Look at
the pressure, check the leak.
The cylinder pressure can be
measured with a pressure gauge to find a cylinder with poor sealing. The reason
for the poor sealing performance of the cylinder is that the valve clearance or
clearance is too small, the clearance between the piston and the cylinder
sleeve and the piston ring end is too large, and the ring groove is carbon
deposited. When the diesel engine is working, if it is close to the air filter,
you can hear the sound of “beep, bang”, which means that the air leak is
related to the valve. At this point, the cause of the fault can be confirmed by
combining the smoke situation.
6. Look at
the exhaust, check the smoke.
When the diesel engine is working
normally, it usually does not smoke or emit some light grayish white smoke,
which is sometimes difficult to see with the naked eye. If black smoke is
emitted, it means that there is less oil in the cylinder and the combustion is
not complete. If blue smoke is emitted, the wear gap between the cylinder liner
and the piston, valve and valve guide is too large; if white smoke is emitted,
the fuel is mixed with water, or the diesel is not completely burned, and
emerges from the exhaust pipe after vaporization.
7. Check
fuel injection pump
The fuel injection pump should
not be deflected, oil-free, well-sprayed,and the range is appropriate. When the
fuel is sprayed, you can hear the sound of cracking, smashing and feel the
pulsation of the high-pressure tubing. Good fuel injection does not fully
explain the problem with the oil system. Therefore, it is also necessary to
check whether the throttle lever and the joint are stuck or loose.
8. Watch the
timing, check early or too late
Seeing the timing means checking
the injection timing, that is, whether the fuel supply advance angle is in
compliance with the regulations. The fuel supply is too late, the diesel engine
is difficult to start, the combustion is not complete, the exhaust smokes, the
machine temperature is too high, and the power is insufficient. If the oil
supply is too early, the diesel engine will have a knocking sound when working,
which will easily damage the parts. It is easy to reverse when starting, and it
also affects the diesel engine power.
9. Look at
the phenomenon, check the circuit
For electronically controlled
diesel engines, the following two conditions will also cause insufficient
diesel engine power.
Thermal protection status: If the
temperature of the electronically controlled diesel engine is abnormal, the
coolant temperature may be too high; the intake air temperature is high; the
fuel temperature is too high; the coolant temperature sensor line is faulty
(such as open circuit); the intake air temperature sensor line is faulty ( Such
as breaking the road);
Failure protection mode: If the
electronic control unit of the electronically controlled diesel engine fails,
the rail pressure sensor may be damaged or the line is faulty; the fuel metering
valve is driven to malfunction, the valve is damaged or the line is faulty.
Comments
Post a Comment