185025
1. Main filter 2. Electric connector 3. Pressure compensation diaphragm 4. Feed pipe from tank
5. Pump module heating liquid inlet pipe 6. AdBlue return pipe to tank 7. Pump module heating liquid outlet pipe -8. Delivery line to dosing module
Figure 43
185029
1. Engine coolant connector 2. AdBlue inlet from tank 3. AdBlue return to tank
-4. AdBlue outlet to dosing module - 5. Pressure sensor - 6. Filter - 7. Diaphragm pump - 8. Valve 4/2.
To prevent any damage to the pump and the dosing module, the supply module contains a filter which cleans the AdBlue of any impurities.
Refer to the procedure described below to replace the filter.
The AdBlue supply module consists mainly of a diaphragm pump which takes up the AdBlue from the tank and sends it to the dosing module.
It is equipped with a circuit connected to the engine cooling system which, in low temperatures, stops the AdBlue from freezing.
Inside there is a pressure sensor.
The amount of AdBlue sent to the dosing module and the injection pressure are controlled by the engine control unit and are dependent on the operating conditions of the engine and from the signals sent by the sensors.
185435
185428
185430
185431
Figure 44
Figure 45
Figure 46
Figure 47
Figure 48
Figure 49 - Unscrew and remove the filter cover (1).
- On the basis of the colour of the filter, insert the correct part of the tool (1) into the filter
- Insert the specific tool (1) until a click is heard indicating that the filter (2) has been completely engaged.
Filter removal
NOTE During installation of the supply module, bear in mind the minimum clearance for replacing the filter.
The minimum measurement is approximately 155 mm.
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185429 185434
185428
185435
Figure 50
Figure 51
Figure 52
Figure 53
Figure 54 - Thoroughly clean the contact surface (1) with water.
- Moisten the gaskets and insert the new filter (1).
- Insert the new compensation element (1).
- Thoroughly clean the filter cover (1).
- Screw on the filter cover and tighten to a torque of 20
± 5 Nm.
Filter assembly
NOTE Make sure that the filter cover and the contact sur-face of the supply module show no signs of being cracked or damaged. If they do, replace the dama-ged components.
NOTE During installation of the supply module, bear in mind the minimum clearance for replacing the filter.
The minimum measurement is approximately 155 mm.
Figure 55 Figure 56 DeNOx 2.5 dosing module (DM - Dosing Module)
193974
1. Power connection - 2. AdBlue inlet - 3. Coolant inlet/outlet.
The dosing module is controlled by the engine control unit. Its function is to dose the AdBlue to be injected into the exhaust pipe upstream of the SCR catalytic converter.
It is fitted on the catalytic converter and while in operation it is subject to high temperatures. For this reason it is connected to the engine cooling circuit by means of the pipes (3).
Maximum AdBlue injection pressure: 9 bar.
DM 2.5 is based on DM 2.2 with improved cooling design.
For DM 2.5 the limit for max. ambient temperature was increased to 140˚C with adjusted useful lifetime (DM 2.2 max. ambient temperature 120˚C). This requires the usage of components with increased temperature robustness.
Benefits:
- Dosing Module can be mounted closer to exhaust gas flow - High lifetime due to low thermal stress
- Robustness against high exhaust gas temperatures
2. 2 version 2.5 version
227499
Figure 57
227482
1. Engine coolant pipe 2. Dosing module coolant pipe -3. AdBlue tank heating fluid pipe - 4. Electrical connector
The diverter is a 2-position 2-way/3-way solenoid valve heats the AdBlue tank and pipes with the engine coolant.
Depending on the temperatures detected by the NTC sensor, the switch valve closes or opens the passage of the engine coolant into the AdBlue tank heating coil. The cooling circuit of the dosing module instead always stays open.
The first position, in fact, allows the cooling of the Dosing Module (DM) whereas the second position allows the heating of the AdBlue tank, the Supply Module (SM) and the relevant pipes, besides cooling the DM.
Diverter valve
Figure 58
227483
3-WAYS DIVERTER VALVE VERSION
1. Engine coolant pipe 2. AdBlue tank heating fluid pipe -3. Electrical connector
2-WAYS DIVERTER VALVE VERSION
Figure 59 NH3sensor
185027
The NH3sensor is connected to the engine management control unit and by detecting the amount of ammonia (NH3) present in the exhaust gas leaving the catalytic converter it allows an exact adjustment of the amount of AdBlue to be injected.
Figure 60
185028
A. Vehicle side connector - B. Sensor side connector.
101. Power supply - 102. CAN LINE H - 103. CAN LINE L - 104. Ground.
Figure 61
1. Positive - 2. Ground connection - 3. CAN LINE L - 4. CAN LINE H - 5. Spare
The NOx sensor detects the amount of nitrogen oxide present in the exhaust gas entering and leaving the catalytic converter.
On the basis of this information the engine control unit adjusts the amount of AdBlue to be injected and also measures the effi-ciency of the catalytic converters.
102302
Nitrogen oxide detecting sensor
NOx SENSOR CHARACTERISTICS NOMINAL
Ambient temperature: - 40 to +105 ˚C
(+105 to +115 ˚C allowed for 10 min)
Cable temperature: 230 ˚C allowed for 100 h
Tightening torque: 50 ± 10 Nm
102303
Figure 62
Figure 63
FUNCTIONAL WIRING DIAGRAM
1. Supply voltage 2. Variable power voltage at output 3. Connector 4. Grey signal cable 5. White ground cable -6. Sensor
It has the function of sending information to the control unit regarding the temperature of the exhaust gas entering and exiting
102304
Exhaust gas temperature sensor
125531
Figure 64
Figure 65
ELECTRIC BLOCK DIAGRAM
1. Power supply unit 2. Percentage of humidity 3. Ground 4. Temperature A. Sample frequency generator -B. Reference oscillator - C. NTC temperature sensor - D. Low pass amplifier filter
102312
1. Power supply - 2. Percentage of humidity - 3. Ground - 4. Temperature
This sensor, which is mounted to the air filter outlet duct, sends the humidity percentage and temperature of the intake air to the ECU These data are used by the ECU to determine the level of nitrogen oxide emissions.
Temperature and humidity sensor
HUMIDITY SENSOR SPECIFICATIONS NOMINAL
Supply voltage 5.00 ± 0.25 VDC
Current absorption 10 mA
Operating range 0% RH to 100% RH
Output impedance 70 ohms
Insulating resistance 1 Mohm @ 500 V
TEMPERATURE SENSOR SPECIFICATIONS NOMINAL
Operating range -40 to 125 ˚C
Resistance at 25 ˚C NTC 2,186 kohms ± 1%
Maximum power at 25 ˚C 100 mW
Tightening torque: 14.5 ± 2.5 Nm
204271
Figure 66
Catalytic converter
The catalytic converter consists of 2 main parts:
- the first stage is made up of a DOC catalytic converter followed by a DPF catalytic converter in which the exhaust gas is cleaned of the HC (unburnt hydrocarbons), CO (carbon monoxide) and the particulate;
- the second stage is made up of a SCR catalytic converter, upstream of which is the AdBlue dosing module; the reactions to reduce the NOx (nitrogen oxide) takes place in this catalytic converter.
192083
Figure 67
Differential pressure sensor
The differential pressure sensor (1), connected downstream and upstream of the DPF particulate filter, measures the corre-sponding difference in pressure.
This difference in pressure is converted into a voltage signal sent to the engine management control unit and consists of a clog-ging index of the DPF particulate filter.