Pierce Enforcer, Operator'S Manual

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OPERATION
5-28 / Engine Exhaust After Treatment Systems
© 2018 Pierce Manufacturing Inc. All Rights Reserved.
5-13.2 Passive Regeneration
Passive regeneration can occur during normal engine operation, typically at higher engine speeds (i.e. highway
driving) and/or high loads, when exhaust temperatures naturally get high enough to oxidize the soot in the DPF. No
engine ECU or operator intervention is required, and the operator will not see a difference in vehicle performance
during the process.
•
No extra fuel is used, and excessive exhaust temperatures do not occur during passive regeneration.
• The DPF light may temporarily illuminate and extinguish if soot levels reach moderately high levels, but because
conditions allow, the passive regeneration process reduces the soot load naturally.
5-13.3 Active Regeneration
Active regeneration is controlled by the engine ECU. The active regeneration process removes collected soot in the
DPF by injecting a small amount of diesel fuel into the exhaust stream. This raises the exhaust temperature to
provide the heat needed to burn off the accumulated soot and regenerate the DPF.
Active Regeneration can happen while the truck is being driven, when in stationary truck operations, or during
pumping operations.
•
The need for active regeneration occurs more frequently within low speed, low load, or stop and go conditions.
• The DPF lamp illuminates when regeneration is needed. When the DPF light turns on, the operator can:
— Provide assistance to the engine by either changing the duty cycle to allow the engine ECU to initiate the
regeneration (Automatic Active Regeneration), or:
— Manually initiate a parked regeneration using the regeneration switch, which is located in the cab within
reach of the driver (Parked / Stationary Regeneration).
5-13.3a Automatic Active Regeneration During Driving or Pumping Conditions
The engine ECU will automatically activate a regeneration when the following vehicle conditions are satisfied:
•
DPF light illuminates (soot is accumulated in the DPF filter) and the ECU looks for opportunities to regenerate.
• Sufficient exhaust flow and temperature conditions (engine fully warm and under load; typical pumping or
highway driving conditions should be adequate).
• Speedometer showing 5 mph or higher vehicle speed, or in pumping mode.
When the ECU initiates the regeneration, exhaust system temperatures will rise, and the HEST lamp will illuminate
with temperatures above 977°F (525°C). Breaking any of the required conditions will stop the regeneration process.
If excessive soot build up remains after the process, the dash lights will indicate the appropriate indication stage for
further regeneration. No engine speed or load changes will occur during regeneration in pumping or driving modes.
Automatic active regeneration can be temporarily suspended using the regeneration inhibit switch. See
“Regeneration Inhibit” on page 5-31 .
The High Exhaust System Temperature (HEST) ight indicates an active regeneration has
been initiated and exhaust system temperatures are elevated above normal levels. The
HEST light will remain on until exhaust temperatures have dropped below 977°F (525°C).
If the HEST light is ON and the vehicle speed has dropped below the threshold of 5 miles
per hour, the light will remain ON until the vehicle speed increases ~3 mph back above the
speed threshold and the regeneration process finishes.