4.15.2.1 HP SCR system - emergency bypass
In this operation mode, the HP SCR system is bypassed. The HP SCR control system opens
the valve V3 quickly. The engine operates in Tier II mode.
If necessary, you can start this operation mode manually. You use the related switch on one of
the control boxes, refer to Para 4.15.3.
The HP SCR control system changes to emergency bypass mode automatically, if a condition
for correct operation of the HP SCR system is not given, for example if a bus connection is
defective.
The valves have the conditions that follow:
•
V1 - Closed
•
V2 - Closed
•
V3 - Open
•
V4 - Controlled by the ECS
•
V7 - Closed, can be opened to decrease the pressure in the reactor
Fig 4-27 HP SCR system - emergency bypass
V1 V2
V3
V7
V4
003
001
007
006
005
004
002
Legend
001 Mixing duct 005 Venting/sealing unit
002 Reactor 006 Urea solution supply unit
003 Turbine of turbocharger 007 Soot blowing unit
004 Engine
X92DF
AA00-9270-00AAA-043A-A
Operation Manual HP Selective catalytic reduction system
Winterthur Gas & Diesel Ltd.
- 123 - Issue 002 2020-08