MQ Power WHISPERWATT DCA600SSV4F3 Operation Manual page 60

SELECTIVE CATALYTIC REDUCTION (SCR)
Diesel engines can be run with a lean burn air-to-fuel ratio,
to ensure the full combustion of soot and to prevent the
exhaust of unburnt fuel. The excess of air necessarily leads
to generation of nitrogen oxides (NO
pollutants, from the nitrogen in the air. Selective catalytic
reduction (SCR) is used to reduce the amount of NO
released into the atmosphere.
DIESEL EXHAUST FLUID (DEF)
Diesel exhaust fluid (DEF) is injected from a separate
tank into the exhaust pipeline, where the aqueous urea
vaporizes and decomposes to form ammonia and carbon
dioxide. Within the SCR catalyst, the NO
reduced by the ammonia (NH
nitrogen (N ), which are both harmless; these are then
2
released through the exhaust.
If the diesel exhaust fluid (DEF) symbol is displayed
during ECU controller operation (Figure 99), it indicates
one or more of the following conditions:
„ DEF tank level is below 10%. Refer to Table 14, DEF
Level System Action System.
„ DEF quality is poor. Check the DEF tank level and check
active diagnostic trouble codes (DTC).
DEF Level
Controller Message
SCR System Pop-Up
DEF Symbol
Pre-Alarm Lamp
Shutdown Lamp
PAGE 60 — DCA600SSV4F3 60 HZ GENERATOR • OPERATION MANUAL — REV. #2 (11/15/22)
), which are harmful
x
are catalytically
x
) into water (H O) and
3 2
Table 14. DEF Level System Action
Over 20% Below 20%
REAGENT TANK
—
LEVEL LOW
— REFILL DEF
—
ON
—
ON
— —
ECU
Series 800 Controller
x
Alarm
Acknowledge
Figure 99. ECU DEF State Pre-Alarm
The amount of fluid in the DEF tank will be shown on the
ECU controller main screen during operation. The symbol
shown in Figure 100 indicating the level of fluid in the DEF
tank will be shown on the ECU screen.
Figure 100. DEF Tank Level Gauge
NOTICE
The unit will enter emergency shutdown 30 minutes
after the DEF level has reached 10% or when other
emergency protective measures are necessary. When
this condition exists, the unit can only run at low idle.
Below 10%
REAGENT TANK
LEVEL LOW
REFILL DEF
Flashing
ON
—
MAINTENANCE
Engine Started
DEF STAT
Shutdown
Pre-Alarm
Screen Program
Option
Change Exit
After 30 Minutes
REAGENT TANK
LEVEL LOW
REFILL DEF
Flashing
—
ON
(Engine Shutdown)