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SEBU9068-03
Engine Operation
Engine Operation
• ECM
• DOC
• SCR
Selective Catalytic Reduction
• RPM
• NOx
Proper operation and maintenance are key factors in
obtaining the maximum life and economy of the
engine. If the directions in the Operation and
Maintenance Manual are followed, costs can be
minimized and engine service life can be maximized.
The time that is needed for the engine to reach
normal operating temperature can be less than the
time taken for a walk-around inspection of the
engine.
The engine can be operated at the rated rpm after
the engine is started and after the engine reaches
operating temperature. The engine will reach normal
operating temperature sooner during a low engine
speed (rpm) and during a low-power demand. This
procedure is more effective than idling the engine at
no load. The engine should reach operating
temperature in a few minutes.
Gauge readings should be observed and the data
should be recorded frequently while the engine is
operating. Comparing the data over time will help to
determine normal readings for each gauge.
Comparing data over time will also help detect
abnormal operating developments. Significant
changes in the readings should be investigated.
In some application the ECM software may be
configured in order to stop an engine from extended
idling.
System check
During normal engine operation the ECM will elevate
the fuel pressure to the injectors. This check will be at
scheduled intervals of approximately 100 hours
depending on the duty cycle of the engine. The check
will be carried out automatically without the need of
any input from the operator.
i05949882
Electronic Control Module
Diesel Oxidation Catalyst
Revolutions Per Minute
Nitrogen Oxide
During the time of elevated fuel pressure, the
operator may notice a change in the tone of the
engine. The ECM will operate the check at low idle
for approximately 5 minutes.
Aftertreatment
The exhaust gases pass through the DOC and then
the mixer where the gases are mixed with the
injected urea. The mixture then enters the SCR
catalyst. Here the NOx in the exhaust reacts with the
ammonia from the injected urea to split the gases into
nitrogen and oxygen constituents. The SCR catalyst
includes an ammonia oxidation section to clean up
any remaining ammonia before the gases exit the
system.
For the aftertreatment system to operate correctly the
operator must ensure an adequate diesel exhaust
fluid supply. The aftertreatment system must operate
correctly in order for the engine to be emissions-
compliant.
Elevated Idle for Aftertreatment
In some applications the engine low idle RPM will
automatically increase in order to lower the rate of
hydrocarbon build-up within the SCR. The elevated
idle is controlled by the engine ECM. The software
within the ECM will calculate the build-up of
hydrocarbon and will increase idle RPM.
The hydrocarbon build-up occurs when the engine is
left to idle for a long period. Operating the engine in
normal load conditions will remove the hydrocarbon
from the SCR.
Constant speed engines and engines with an idle
speed at or above 1100 RPM will not require the
increase in the idle speed.
In some application the ECM software may be
configured in order to protect the aftertreatment
system from high hydrocarbons build up. This
protection will shut down the engine.
Engaging the Driven
Equipment
1. Operate the engine at one-half of the rated rpm,
when possible.
2. Engage the driven equipment without a load on the
equipment, when possible.
55
Operation Section
Engine Operation
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