Belarus 3522.5, Operator'S Manual

Page: 93 / 340

3522.5-0000010
РЭ
94
The SCR operation principle is based on reduction of nitrogen oxide (NOx) level in exhaust
gases to reach a required level. For this reason AdBlue agent is injected in the mixing pipe 6 in front
of the SCR catalyst 3 by means of the dosing module 12. The location of the dosing module, dimen-
sions and form of the mixing pipe ensure max. even distribution of AdBlue agent at the entrance to
SCR catalyst. In SCR catalyst in presence of the inbuilt catalyst a chemical reaction of NOx reduction
to nitrogen (N
2
) and water vapour (
Н
2
О
), that are safe for the environment, occurs. To maintain opti-
mal temperature mode on the mixing pipe surface, heat insulation of the mixing pipe is provided. To
control temperature of exhaust gases a temperature sensor 13 is mounted on the mixing pipe. Ad-
Blue agent is supplied by the feeding module 19. A required quantity of the injected AdBlue agent is
controlled by a sensor of exhaust gas chemical composition, located behind the SCR catalyst. Ad-
Blue agent is filled into a special tank 1. AdBlue warm-up pipeline is attached to the tank 1, which is
equipped with sensors of AdBlue temperature and AdBlue level. AdBlue consumption makes ap-
proximately 5 to 10% of diesel fuel consumption. To ensure a SCR optimal operation mode as well
as SCR operation ability under low ambient temperatures, heating (cooling) of some parts and units
of SCR system is provided.
Heating of AdBlue tank and cooling of the dosing module is performed by the engine cool-
ing system. The dosing module is permanently connected to the tractor cooling system, and the
AdBlue tank is connected by means of electromagnetic valve when required. The pipelines for urea
transportation and pipelines of the feeding module are heated by means of electronic system of
engine control when necessary. SCR system operation is functionally linked with the electronic
system of engine control.
A general structural diagram, illustrating interconnection of SCR system units, is presented
in figure 3.1.6. All lines of connection and flow directions of AdBlue as well as engine coolant are
shown in the diagram.
Figure
3.1.6
– Structural diagram of SCR system
injector
View A
Cab
Urea line
Urea warm-up line
Heater line
Injector cooling (ouput)
Injector cooling (input)
Urea heater
in the tank
Heat valve
Urea tank
Feeding
module
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