An EBPR check is performed by the service test
before starting the regeneration process.
If an EBPR issue is present, the procedure will abort
and an error identifier will be generated.
The procedure assesses the DPF soot load. If soot
loading is too high to allow HC Dosing, the procedure
will use elevated idle and the EBPR to reduce the
soot load. The procedure will target a desulfation-
specific desired cylinder head pressure differential.
The procedure waits for several seconds before
taking an average of the measured pressure
differential. If the target is not met, an error identifier
will be displayed, indicating EGR intake pressure is
not responding.
If the pressure differential check passes, the
procedure checks that the DPF intake temperature is
above a minimum pass threshold. If the minimum
temperature threshold is not met, an error identifier is
displayed, indicating that the DPF intake temperature
is too low. Once the system verification steps are
complete, the procedure will continue to run for a set
time to desulfate the DPF.
If the soot load is reduced sufficiently, the procedure
assesses whether the system can generate the
required SCR intake temperature. This temperature
is required to remove any urea or sulfur from the
aftertreatment. A higher DOC intake temperature
than normal is targeted to ensure that light-off occurs
the first time.
If the DOC intake temperature is reached, HC dosing
will be initiated automatically. The procedure will
check for adequate heat rise across the DOC during
the HC dosing ignition phase. If the temperature rise
is not sufficient, the procedure will perform the DPF
desulfation procedure before attempting HC Dosing
again. If the DOC fails to ignite again, the procedure
will abort with an error identifier.
Note: If DPF desulfation had been previously
performed due to high soot load, the test will abort
immediately with an error identifier. HC dosing will
not be attempted.
If the heat rise target is achieved, the procedure will
continue to increase the amount of HC dosing. HC
dosing increases until the DPF intake temperature
stabilizes at the target value of approximately 475° C
(887° F).
If this part of the procedure is successful, HC dosing
will continue until the required SCR intake
temperature of 475° C (887° F) is achieved. The
procedure then maintains this temperature for a set
time to remove sulfur and/or urea deposits from the
SCR catalyst.
Aftertreatment Recovery Procedure
(Non-DPF Engines Only)
Note: This procedure is only applicable to engines
that do not have a DPF in the aftertreatment system.
Avoid contact with hot surfaces. Exhaust piping
and engine components become hot during en-
gine operation and cool slowly after engine shut-
down. Any contact with hot surfaces can cause
severe burns.
This test must be run with the engine running and the
machine/engine out of a working mode. The engine
must be warmed up to a minimum coolant
temperature. Once the coolant temperature
conditions are met, a pop-up screen will advise that
the engine speed will be automatically increased
after the warning is accepted.
Once the pre-conditions are met (no relevant active
diagnostics, coolant temp condition met, elevated
speed in range), the system test will begin. The
EBPR valve control logic will determine the
appropriate desired cylinder head pressure
differential. This determination is reached with a
dedicated fueling and injection timing calibration
which should result in the target SCR intake
temperature being met. The test will then wait for the
SCR intake temperature to rise above a minimum
pass threshold. If the minimum temperature
threshold is not met, an error ID will display “SCR
Intake Temperature Too Low” .
Once the SCR intake temperature is acceptable, a
timer shows the remaining service test time for the
recovery stage of the procedure. This remaining time
depends on the observed SCR intake temperature.
The remaining time may decrease rapidly whilst the
SCR intake temperature continues to rise above the
minimum acceptable temperature. The high
temperature at the SCR intake will help recover the
system performance. This stage may take up to 4
hours. Usually, this stage will take less than 4 hours.
After the high temperature recovery completes, the
service test changes the engine operating conditions
(at the elevated speed) for the SCR performance to
be assessed. If the performance is found to be
satisfactory, the test will be considered successful.
Manual DPF Regeneration
Note: This test is only applicable to engines that
have a DPF in the aftertreatment system.
UENR4469-36 461
Service
Copyright of Perkins Engine Company Limited. NOT FOR REPRINTING OR RESALE
To Next Page
Loading...
