44
Rev. 06/2020
7.1
NOx Emission Control
The emission regulation is carried out in two steps:
Feed Forward Control
The required AdBlue
®
injection quantity is calculated from the measured values of the NO
X
sensor before of the catalytic converter, the MAP and MAT sensors and the exhaust gas
temperature. The calculation is carried out with the aid of a map table with up to eight points.
This can be configured via the MICT (see
Exhaust Control – SCR – Feed Forward Control
on
Adjustment
Based on the measured value of the NO
X
sensor after the catalytic converter, a digital PID
controller adjusts the configured emission value. By changing the opening time of the dosing
valve, the AdBlue
®
injection quantity is adjusted until the corresponding NO
X
value is reached.
The range of the PID controller is limited by the parameters of the map table of the feed forward
control, thus overdosing is avoided. The emission value and the settings for the PID controller
can be configured in the MICT (see
Exhaust Control – SCR – Dosing Valve
7.2
Pump Self Test
The pump self test checks whether the pump speed and pump pressure are within the minimum
and maximum values specified in the configuration. Two types of pump self test are performed
automatically by the VariSCR emission controller:
–
Initial Self Test
The initial self test is performed automatically after starting the emission controller and
after each error acknowledgment. In addition, the initial self test can be started manually by
the user via the menu command
Device -> Pump check
.
–
Continuous Self Test
The continuous self test is performed permanently during operation of the emission
controller.
The parameters for the pump self test are defined on the corresponding configuration page in
the MICT. Refer to the section
Exhaust Control – SCR – Pump Self Test
on page 67.
7.3
Control of the Pressure of the Pump
The pressure of the pump is adjusted by a digital PID controller which reacts to the pressure
signal of the dosing unit. The actual pressure is set by regulating the pump speed. The target
pressure and the settings of the PID controller can be configured in the MICT. Refer to the
section
Exhaust Control – SCR – Pump Setup
on page 66.
7 Functions
Содержание VariSCR
Страница 1: ...VariSCR NOX Emission Controller Operating Manual P N 01 50 025 EN Rev 06 2020...
Страница 111: ...Rev 06 2020 111...
Страница 112: ......
