WÄRTSILÄ PAAE051728, Instruction Manual

Page: 270 / 394

16.4.4 Testing of nozzle function in general
·
If abnormal running parameters are observed (abnormally
high or low exh. gas temperatures, low firing pressure) one
reason can be leaking or blocked fuel injector(s).
·
The nozzle holes can be checked with the hand test pump by
giving a quick and heavy blow and using a paper under the
nozzle tip, but keep your hands away . All sprays should give
an equal impression on paper; the number of impressions
should correspond to the hole configuration (10 holes). An
irregular form tells that the hole is partly blocked and should
be cleaned.
·
Testing of nozzle atomization with the hand test pump
however is not completely reliable. When using hand test
pump, the injected fuel amount is very small. Therefore, the
needle stroke is very short and may give an impression of
bad atomization.
A nozzle that gives bad atomization on the test pump can give
good performance on an engine.
Fot tests of the nozzle function with fully amount of fuel injected,
a special booster unit is developed and can be ordered as an
optional tool.
16.4.5 Function of the booster unit
The aim with the booster unit after the hand test pump is to
provide waving fuel pressure with a right quantity to the nozzle.
The booster unit is operating as follows:
1 Fuel is supplied
from the hand test pump device through
the port (1) to the chamber (2). see Fig 16-6.The first filling of
the booster requires about 80 strokes.
2 If the booster unit
has not been used, the trapped air is
pumped out (requires 5-8 strokes) through the lower valve (3)
to the leak channel. Close the valve (3) after venting the booster
unit.
3 The right pressure wave level
is reached by pumping
prepressure to the high pressure line to fuel injector. This is
done by opening the valve (4) and pumping with the test pump
the pressure little over 200 bar. After this the valve (4) should
be closed.
16 Injection System 32-200627-01
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