Exhaust Aftertreatment System; Filtration And Regeneration Unit; Passive Regeneration; Active Regeneration - PREVOST H3-45 VIP Owner's Manual

EXHAUST AFTERTREATMENT
SYSTEM
The exhaust aftertreatment system consists of two
units, the filtration and regeneration unit and the
selective catalytic reduction SCR unit.

FILTRATION AND REGENERATION UNIT

The main purpose of the filtration and regeneration
unit is to capture and oxidize (regenerate) the
particulate matter (soot) in the engine exhaust gas.
The exhaust gas first enters the Diesel Oxidation
Catalyst (DOC) and then flow through the Diesel
Particulate Filter (DPF); together they capture and
regenerate the soot on a regular or passive basis.
Through constant monitoring of the exhaust gas
temperature and the system back pressure, the
engine control module
regeneration.

PASSIVE REGENERATION

Passive regeneration is the process by which the
particulate matter is oxidized due to the heat
generated by the engine internal combustion
process. During normal highway operation, exhaust
temperatures alone are usually high enough to
oxidize accumulating
temperatures, however, or in some stop- and- go
applications, the system needs a little help to
regenerate, or clean itself. This process is called
"active" regeneration.

ACTIVE REGENERATION

Active regeneration is necessary when the engine
internal combustion process alone does not generate
enough heat. A dosing system injects a mist of
diesel fuel into the exhaust system to increase and
maintain the aftertreatment system temperature.
Exhaust temperature must be above 572°F (300°C)
to initiate the oxidation catalyst, which in turn
oxidizes the injected diesel fuel molecules to
achieve up to 1200°F (650°C) exhaust temperature
at the particulate filter. This process of active
regeneration takes place during the normal operation
cycle of the vehicle without charges in performance
or control for the operator. EPA2010 compliant and
later Volvo engines produce less soot, so less active
or stationary regeneration will be required.
is able to manage
soot. In low ambient
PA-1638 Owner's Manual X3-45 VIP

STATIONARY (PARKED) REGENERATION

In a small number of specific engine duty cycles,
engine control module may not be capable of
completing an active regeneration.
situations, the operator will be notified that a
stationary or parked regeneration may be required. A
DPF telltale light will illuminate indicating the need
for user interaction. The lamp gives the operator a
grace period to allow this process to take place at a
time when most convenient for the operator. This
process requires the vehicle to be parked while a
driver or maintenance technician initiates the
regeneration process using the DID menus. Once
initiated, the stationary regeneration process will be
complete in about 45 minutes.
The driver will be notified of the need for a stationary
regeneration (parked) by illumination of the DPF
Regeneration telltale light.
Other Features 5-3
In these