Exhaust Cleaning 291; General - Volvo FM Handbook

General

Volvo Trucks use SCR technology
(Selective Catalytic Reduction) catalytic exhaust gas
cleaning — to meet the requirements of Euro 4, the
new standard for exhaust gas emissions that came into
force on 1 October 2006. A new EU legal requirement
is introducing 1st October 2007 in order to monitor the
fulfillment of exhaust emissions for Euro 4 and Euro 5
engines. In addition to the existing
OBD-system (On-Board Diagnostic) the law requires
that there must also be a special level and diagnostic
system for the engine's exhaust gas after-treatment
system, which is known as NOx control monitoring
(NOx = nitrous oxides).
NOx control monitoring system is to monitor:
• The level of NOx in the exhaust.
• The level of AdBlue in the tank.
• Faults in the emission control monitoring system.
The following effects will occur if faults are detected
in the exhaust gas after-treatment system:
• The monitoring system will inform the driver via
warning lamps and fault messages.
• "Non-erasable fault codes" are set.
• Possible derating of the engine (depending on type
of fault).
Conditions
The NOx control monitoring system is only active
under the following conditions:
• Ambient temperature —7 C to +35 C.
• Altitude above sea level less than 1600 m.
• Coolant temperature above 70 C.
In order for a "non-erasable fault code" to be set
(activated), a number of different basic conditions

Exhaust cleaning 291

Note!
These conditions do not apply if the
AdBlue tank is empty.
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