Engine Exhaust After-Treatment - Sullair 185CFM User Manual

3: Description

3.11 Engine exhaust after-treatment

Tier 4 engine emission regulations require the installation
of exhaust filters (EF) on most engines. The exhaust fil-
ters discussed here consist primarily of a diesel oxidation
catalyst (DOC) and a diesel particulate filter (DPF). The
exhaust flows from the engine through the DOC and then
the DPF. The DOC reduces hydrocarbon (HC) emissions,
enables passive regeneration of the DPF, and oxidizes
dosed hydrocarbon for active cleaning of the DPF. The
DPF traps diesel particulate (primarily carbon soot) from
the exhaust. Any engine fitted with an EF must be run on
ultra-low sulfur fuel and low ash CJ-4 or equivalent lubri-
cating oil.
During normal operation, the diesel particulate filter
(DPF) accumulates soot. When that soot level reaches a
certain level, the engine control unit (ECU) determines
that the DPF needs to be cleaned or "regenerated". At
that time, the ECU prepares the diesel oxidation catalyst
(DOC) through exhaust temperature management. When
the DOC reaches the required temperature, hydrocarbon
(HC) fuel dosing is activated.
After a period of high temperature cleaning, the DPF is
ready to trap more particulate and the engine returns to
30
02250216-781 R02
Subject to EAR, ECCN EAR99 and related export control restrictions.
normal operation. The frequency of cleaning is highly
dependant on the engine operating conditions.
Your Sullair compressor's engine exhaust regenerates in
one of several different ways, depending on the com-
pressor's operating conditions.
• Passive regeneration. Continuous regenera-
tion due to high exhaust temperature.
• Active regeneration. Automatic controlled
regeneration with the aid of post injection
despite low exhaust temperature. Machine
operation is not interrupted.
• Parked regeneration. Machine is manually
placed in Start mode and the FORCE/REGEN/
INHIBIT switch is in the FORCE position. Nor-
mal operations are not possible in parked
regeneration. Machine should be left to finish a
parked regeneration unless it is absolutely nec-
essary to take it out of regeneration or to shut
down the machine. If machine is not allowed to
regenerate while in parked regeneration, the
DPF may become damaged and need to be
serviced or replaced.
185 T4F Kubota User Manual