T-378
3–2
3.2 Exhaust System Description
3.2.1
Diesel Oxidation Catalyst (DOC)
Exhaust flows through the Diesel Oxidation Catalyst (DOC),
, for initial filtration. Fuel is injected into the
DOC to increase temperatures in the Diesel Particulate Filter (DPF) during regeneration. Refer to
for a
description of how regeneration works. There are no service requirements for the DOC.
Figure 3.2 Diesel Oxidation Catalyst (DOC)
3.2.2
Diesel Particulate Filter (DPF)
The Diesel Particulate Filter (DPF),
, traps particulate matter in a filter but allows exhaust gas to pass
through. The DPF uses a Wall Flow Filter (WFF) design, which allows exhaust gases to pass through micro-porous
walls. Particles of diesel soot and other debris is removed from the gas stream by filtration, but soot remains
trapped in the DPF. As the amount of soot increases in the DPF, the back pressure in the exhaust increases as
well. When the back pressure reaches a predetermined level, regeneration will occur to convert the captured soot
into inorganic ash. Refer to
for a description of how regeneration works. The DPF requires periodic
ash removal and filter cleaning. Refer to
for DPF Cleaning procedure.
Figure 3.3 Diesel Particulate Filter (DPF)
Wall Flow Filter (WFF)
