Passive regeneration
In passive regeneration, the exhaust constituents / temperature are at an
appropriate level where some soot can be reduced or oxidized (burned)
thus cleaning the filter. This method occurs naturally as a result of
normal engine operating conditions (at varying levels due to drive
patterns).
Active regeneration
If there is not enough passive regeneration naturally occurring due to
vehicle drive patterns, the engine control system will initiate an active
regeneration. In an active regeneration, the filter is cleaned by raising
the exhaust temperature to a point where the soot is burned away. This
is accomplished through various engine actions which raise the exhaust
temperature in the oxidation catalyst/DPF system to an appropriate high
level where the soot is burned off. After the soot is burned off, the
exhaust temperature and back-pressure (restriction) fall back to normal
levels.
Filter service/maintenance
Over time a slight amount of ash will build up in the DPF which is not
removed during the regeneration process. The DPF may need to be
removed for ash cleaning at approximately 120,000 miles (193,000 km)
or greater (actual mileage can vary greatly depending upon
engine/vehicle operating conditions) and replaced with a new or
remanufactured (ash cleaned) part. The filter may need to be replaced
at approximately 250,000 miles (400,000 km) depending upon
engine/vehicle operating conditions. In both cases the engine control
system will set a service light (
) to inform you to bring the vehicle
to the dealer for service.
If there are any issues with the oxidation catalyst/DPF system a service
light (
or
) will be set by the engine control system to inform
you to bring the vehicle into a dealership for service.
Resonator/Tailpipe assembly maintenance
The diesel resonator tail-pipe assembly is a uniquely functioning device
that accompanies the Oxidation Catalyst/DPF assembly. The assembly
serves multiple functions. First it serves as an acoustic device to
attenuate exhaust noise. Second it provides an exit path for the exhaust
from the vehicle. It also is designed to help control the temperature of
the exhaust during DPF regeneration events. The visible holes in each
leg of the twin tip and the holes under the shield just inboard of the
2009 Econoline
(eco)
Supplement, 1st Printing
USA
(fus)
Maintenance and Specifications
52
