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4.4.2 Delivery
On vehicle, engine management systems can compensate for small variations in injector delivery by
trimming the pulse width to individual injectors. Therefore on the test bench you may well see slight
differences between injectors at a given test point (depending on the delivery volume).
suggested maximum spread is 2mm
4.4.3 Backleakage (with HK901)
Common Rail injectors have inherently higher backleak than traditional injectors as a volume of fuel is
expelled every time the injector valve operates (see Section 3). Typically for a good injector this
dynamic backleak volume is of the same order of magnitude as the delivered volume.
The Static Backleak test focuses purely on the inherent tightness of the injector in a static condition
and so gives an indication of the condition of the injector valve seats and clearances. This is similar
to testing backleak on a traditional injector and is measured over time (mm
For both the dynamic and static backleak tests, any injector with a significantly higher flow (and
temperature) compared to the others should be regarded as suspect.
4.4.4 Summary
In general when testing a set of 4 injectors the faulty injector(s) will have:
higher response time
lower delivery
higher backleakage
4.5 Creating/Editing/Saving Testplans
In the Testplan Menu (Figure 4.2), pressing [New] creates a copy of the currently loaded testplan.
You will be prompted for a new testplan name (we suggest that you use the injector part number as
the testplan name), and then the following dialog box will appear with the general testplan/injector
parameters.
Max Speed, Max Pulse Width, and Max Pressure are all safety limits which you can set at the
maximum for the injector concerned (if then while running the testplan you type in a higher value the
software will not allow it). You can set the speed ratio between engine and pump, and also select
whether you want to set the speed in terms of Pump RPM or Engine RPM. T40 or T0 is the standard
bench metering temperature compensation. In this dialog you can also set the limits for resistance
and response time. When you are happy with the changes, press [OK] to go back to the Testplan
Menu (you will be asked for confirmation to overwrite the testplan), then [OK] to return to the main
screen.
NOTE:
You can only edit testplan parameters for the testplan that is loaded (the [Edit Parameters]
button will be greyed out otherwise).
HL030(EN), Issue 1, June 2005
THIS IS AN UNCONTROLLED DOCUMENT downloaded by Lukas Matuska on 16 Feb 2016
Any technical intervention requires certified Hartridge training. Contact Hartridge Ltd for details.
3
for deliveries up to 20mm
Figure 4.7: Injector Parameters Dialog
Operating Manual
3
/stk, and thereafter 10% of delivery.
3
/sec).
The
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