Exhaust system |
13 | Selective Catalytic Reduction (SCR) catalytic converter |
N74 | Soot particulate sensor control unit |
N74b1 | Soot particulate sensor |
P14.00-2186-75
Location
The soot particulate sensor is located in the exhaust pipe downstream of the SCR catalytic converter. The soot particulate sensor control unit is located on the underfloor.
Task
The soot particulate sensor records the soot particle concentration in the exhaust gas downstream of the SCR catalytic converter and from this, it derives the filtration efficiency of the diesel particulate filter. The soot particulate sensor control unit reads in the signals from the soot particulate sensor directly and transmits them to the CDI control unit (N3/9) via the drive train sensor CAN (CAN I).
The soot particulate sensor control unit has the following tasks:
Reading in of sensors and signals
Evaluation of input factors
Actuation of components
Output of signals
Reading in of sensors and signals
The input factors are read in via the following connections:
Direct line
Drive train sensor CAN
Direct line
The soot particulate sensor control unit reads in the signals from the soot particulate sensor directly.
Drive train sensor CAN
The soot particulate sensor control unit receives the following information via the drive train sensor CAN:
Measurement request
Engine running status
Cold start status
Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.
Actuation of components
The soot particulate sensor control unit actuates the sensor heater of the soot particulate sensor directly.
Output of signals
The soot particulate sensor control unit transmits the following signals via the drive train sensor CAN:
Soot particulate sensor status
Signal regarding soot particle concentration in exhaust
The soot particulate sensor is inseparably connected to the soot particulate sensor control unit via 5-pin signal line. A temperature sensor for monitoring the exhaust gas temperature and a heating element are integrated in the soot particulate sensor.
Structure |
N74 | Soot particulate sensor control unit |
N74b1 | Soot particulate sensor |
a | Signal wire |
b | Electrical connection |
P14.40-2644-10
Function
The soot particulate sensor is designed as a ZrO2 sensor. It is fitted with an integrated heating element for periodical regeneration of the sensor and interdigital electrodes for determining the soot particle content in the exhaust. Exhaust cleaned of soot particles creates voltage between the interdigital electrodes here. The reaction time until a defined voltage value is exceeded is decisive for determining the soot particle content.