Bosch KMA 802 Originalbetriebsanleitung Seite 33

5. Prevention of
contamination
To determine the injection volume / delivery rate, the
continual measuring technology KMA 802 incorporates
precision mechanical components such as change-over
valves or flow meters. Because of the necessary clea-
rances on moving parts, foreign particles ranging in size
from 20 µm – 40 µm can cause malfunction and subse-
quent failure of the measuring system. Smaller particles
< 20 µm pass through the measuring system without
any adverse effect.
On run-in and unopened injection systems, the propor-
tion of foreign particles 20 µm – 40 µm is very low, as
the vehicle-fitted fuel filter upstream of the injection
pump can filter out particles > 10 µm. On new injection
pumps, any critical foreign particles are filtered out as
soon as operation starts on the engine.
More critical are the repaired injection pumps in which
replacements parts such as pump housing or pump
elements have been fitted which still contain residue
from this process which can then enter the measuring
system during subsequent testing of the pump. Ge-
nerally this is caused by insufficient cleaning of these
replacement parts.
Robert Bosch GmbH
Prevention of contamination | KMA 802/822 | 33
To prevent foreign particles from entering the measu-
ring system, the following is recommended (only
applies when testing in-line and distributor injection
pumps):
1. Rinsing before measurement
During the specified warm-up time (3 to 5 minutes),
the injection pump is to be flushed before the first
flow measurement. This is done before starting the
test bench by opening the bleed screw on the test
nozzle holder and then running the pump. The test
oil then flows through the bleed elbow on the test
nozzle holder into the drain channel of the measu-
ring device. The metal particles by-pass the measu-
ring system in this way. To prevent oil splashes,
these elbows can be fitted with transparent hoses,
which lead into the collective drain channel of the
measuring device or into the test-oil tank of the test
bench. The majority of foreign particles then go
directly into the test-oil tank. This oil circuit is provi-
ded with course and fine filters. These filters retain
the foreign particles. Before starting measurement,
the bleed screw on the test nozzle holder must be
re-closed.
2. Installation of auxiliary filters upstream of change-
over valves /flow meters.
i
For KMA 802 measuring technology, there is a retro-
fit kit for subsequent installation in the measuring
system. This retrofit kit 1 687 001 509 includes 6
fine filters, fastening parts and installation instruc-
tions.
en
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1 689 979 674 2013-12-23