1.Back
pressure of compressed air in cylinder
When Back pressure of
compressed air in cylinder of generator set increasing, density of compressed
air will increase, which can increase air resistance acting on fuel spray.
Therefore, fuel atomization can be improved, spray cone angle is increased, and
range is reduced. In the non supercharged diesel generator, the reverse
pressure of the compressed air in the cylinder does not change much, so it has
no significant effect on the characteristics of the oil spray.
2.Fuel
pump cam contour and speed
When the cam contour is
steep or the camshaft speed is high, the speed of fuel supply in plunger of
injection pump will increase. Because injector orifice reduces expenditure,
fuel can not flow out directly. Which causes fuel pressure in fuel pipe
increased and the speed at which fuel flows out of the orifice increased.
Therefore, fuel spray and spray cone angle increases.
3.Fuel
viscosity
When the viscosity of
the fuel increases, the fuel particles are not easy to disperse into fine
drops, resulting in poor atomization. Therefore, for high-speed diesel
generators, we generally select light diesel oil with low viscosity as fuel
oil.
4.Structure
and size of fuel injector
Different structure of
injector, the internal perturbation of oil spray will be different, which
produce different types of oil spray. The fuel bunches should be closely
matched with the combustion system. Different combustion modes require
different oil spray, so the fuel injectors with different structures are used.
Under the conditions of
unchanged injection pressure, back pressure of compressed air in cylinder and
the total size of injector hole, to increase the quantity of injector hole, as
the diameter of each orifice decreases, fuel will be throttled more when it
flows out of the orifice. So the disturbance increases in the orifice.
Therefore, the quality of atomization is improved. If diameter of each orifice
increases, the core of the oil spray is dense and the range is increased.
5.Injection
pressure
The bigger injection
pressure, the bigger initial speed of fuel outflow. Degree of fuel disturbance
in the injector hole is bigger, and resistance of compressed air after fuel
flow out injector hole, so that the fineness and uniformity of atomization are
improved, that is a good quality
atomization. When injection pressure increases, range of oil spray will
increase.
How
to maintain injector of diesel generator set?
In order to make the
fuel injected into the cylinder by the injector burn completely in time, the
oil supply time of the oil pump must be checked regularly. If the fuel supply
time is too early, the unit will have difficulties in starting and knocking fault.
If fuel supply time is too late, it will lead to black smoke from exhaust, high
temperature and increased fuel consumption. The fitting accuracy of the
injector needle valve is very high, and the orifice diameter is very small, so
we must select specific diesel oil by seasonal variation. Otherwise, the fuel
injector can not operate normally.
Do not collide with
other hard objects or drop them to the ground when cleaning the needle valve
parts of the fuel injector to avoid damaged. When replace the needle valve
parts of the fuel injector, should immerse the new coupling in 80℃ hot diesel oil for
about 10 s. After antirust oil is fully dissolved, spasm the needle valve back
and forth in the valve body in clean diesel oil, and thoroughly clean it. In
this way, the failure of sticking needle valve due to the dissolving of
antirust oil can be avoided.
Above information is
about the reasons of fuel atomization poor in diesel generator set, hope
it is helpful to you. When you meet the problem, you can check and remove
faults by above reasons.
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