Fuel tank
12 13 PCM
DPF differential pressure sensor 14
DPF
A B
1
2 c
d
1
A B 2
1
2 c
d
1 2
E97467
DPF/oxidation catalytic converter unit in the 1.6L Duratorq-TDCi (DV) diesel engine A
DPF in the 2.0L Duratorq-TDCi (DW) diesel engine
B
Exhaust gas temperature sensor 1
Pipes to the DPF differential pressure sensor 2
Oxidation catalytic converter c
DPF d DPF of the 1.6L Duratorq-TDCi (DV) engine:
• The DPF is located downstream of the catalytic converter in the flow direction of the exhaust gases.
• The oxidation catalytic converter and DPF are combined in one housing.
DPF of the 2.0L Duratorq-TDCi (DW) engine:
• The DPF is contained in a separate housing, downstream of the oxidation catalytic converter.
The diesel particulates contained in the exhaust gas are deposited in the DPF. The pressure drop across the DPF (measured via the DPF differential pressure sensor) is an indicator for the soot load of the filter.
The soot load capacity of the DPF is limited, however, so that it has to be regenerated at regular intervals (burning of the diesel particulates).
After regeneration, ash residues that have formed from the fuel additive, engine oil and fuel remain in the DPF.
These constituents cannot be further converted and can only be deposited in the DPF up to a certain degree.
This means that the DPF must be renewed at prescribed service intervals (see the current Service Literature).
DPF with fuel additive system Lesson 6 – Engine Emission Control
Charge air cooler bypass
System in the 1.6L Duratorq-TDCi (DV) diesel engine
E51462
1
2
3 4
5 7
8
9
6 10
MAP sensor 1
Intake manifold flap housing 2
Charge air cooler bypass 3
Combined IAT and MAF sensor 4
Connecting piece between turbocharger and charge air cooler
5
Charge air cooler 6
Turbocharger vacuum actuator 7
Charge air cooler bypass flap actuator motor 8
Connecting piece between charge air cooler and intake manifold flap
9
Intake manifold flap actuator motor 10
Lesson 6 – Engine Emission Control DPF with fuel additive system
System in the 2.0L Duratorq-TDCi (DW) diesel engine
E54232
Connecting piece between air cleaner housing and turbocharger
1
Combined IAT and MAF sensor 2
Charge air cooler 3
Connecting piece between turbocharger and charge air cooler
4
Charge air cooler bypass 5
Charge air cooler bypass flap vacuum actuator 6
Intake manifold flap housing 7
Turbocharger 8
Intake manifold flap vacuum actuator 9
Connecting piece between charge air cooler and intake manifold flap housing
10
DPF with fuel additive system Lesson 6 – Engine Emission Control
An intake manifold flap housing has been added to the intake system in conjunction with the DPF system. The intake manifold flap housing contains the following components:
• charge air cooler bypass flap,
• intake manifold flap,
• MAP sensor,
• IAT sensor (not illustrated).
The intake manifold flap creates the connection between the cooled air from the charge air cooler and the intake ducts of the engine via the intake manifold flap housing.
The charge air cooler bypass flap creates a direct connection between the compressor side of the turbocharger and the intake ducts of the engine via the
intake manifold flap housing. The charge air cooler is bypassed. The charge air cooler bypass flap is only adjusted during the regeneration phase.
During the regeneration phase, the air mass flowing through the charge air cooler (regulated by the intake manifold flap) is reduced.
At the same time, the flow of uncooled air mass via the charge air cooler bypass (regulated by the charge air cooler bypass flap) is increased.
This reduces the engine's cylinder charge while keeping the intake air temperatures constant. Variations in exhaust gas temperatures are thereby prevented during regeneration.
The position of both flaps is dependent on the intake air temperature. For this reason, there is an additional IAT sensor at the intake manifold flap housing, downstream of the intake manifold flap and charge air cooler bypass flap.
Fuel additive system – general
E51469
1 2 3
4 5
6
Fuel tank 1
Hoses for fuel additive (top up and ventilation) 2
Fuel additive tank 3
Fuel additive pump unit 4
Lesson 6 – Engine Emission Control DPF with fuel additive system
Fuel additive line to the injector
5 6 Injector
The fuel additive system comprises the following components:
• a fuel additive tank with a fuel additive pump unit,
• fuel additive lines,
• an injector.
In addition, a tank flap switch and a fuel additive control unit are installed in the vehicle (not illustrated).
The fuel additive is injected into the fuel tank via the fuel additive pump unit, the fuel additive line and the injector.
The fuel additive mixes with the diesel fuel in the fuel tank. The quantity of the fuel additive to be injected is dependent on the diesel fuel quantity at each refuelling.
Components of the fuel additive system
Fuel additive
Metallic catalysts, cerium and iron, are used as fuel additives. These accelerate burn-off of the diesel particulates and lower the temperature at which burn-off can occur.
Each time after the fuel tank is filled, a metered quantity of fuel additive is injected into the fuel tank where it mixes with the fuel.
When combustion takes place, the cerium and iron traces mix with the particulates from the diesel exhaust gas and provide for a considerably lower burn-off temperature.
As a result, the particulate matter collected in the filter can be burned off at temperatures of just over 450 °C.
The homogeneously bound cerium oxide/diesel particulate matter is then filtered out by the DPF, where it becomes embedded.
Thanks to the combination of fuel additive (reduction in the burn-off temperature of the particles) and the engine management system (increase in the exhaust gas temperature), the DPF can be regenerated not only under full load conditions, but also in the partial load range at comparatively low exhaust gas temperatures typical for urban traffic.
Fuel additive tank
E48498
1
5
2 3 4 6
Fuel line to the fuel tank 1
Overflow (when filling) 2
Fuel filler connection 3
Fuel additive tank 4
Fuel additive pump unit 5
Vent assembly 6
The fuel additive tank is located behind the fuel tank and is attached to the crossmember. The fuel additive tank forms a unit together with the fuel additive pump unit and can therefore only be renewed as a whole.
The fuel additive tank has a capacity of 1.8 litres for an average total mileage of 60,000 km. Therefore, the fuel additive has to be topped up according to the service specifications.
Note: The fuel additive tank cannot be emptied fully.
Once the quantity remaining falls below 0.3 litres, fuel additive injection ceases (the driver is informed before this occurs by means of the relevant warning indicators).
The residual quantity prevents the fuel additive pump from drawing in air, which could result in incorrect quantities of fuel additive being metered.
The maximum top-up quantity is therefore 1.5 litres.
DPF with fuel additive system Lesson 6 – Engine Emission Control
Fuel additive pump unit
E48499
3 2
1
Connection to the fuel tank 1
Fuel additive pump 2
Piezo sensor 3
The fuel additive pump unit is designed as a
displacement-type pump (piston pump). It feeds the fuel additive, metered according to the command issued by the fuel additive control unit, via a short fuel line to the injector where it is injected into the fuel tank.
The piezo sensor at the bottom end of the fuel additive pump unit contains two sensor elements with the following functions:
• They determine changes in the viscosity of the fuel additive as a result of changes in ambient
temperature.
• They detect when the fuel additive tank is empty (measurement of the precise fuel level in the fuel additive tank is also envisaged and will be implemented at a later date).
In the event of an empty fuel additive tank, initially the engine system fault warning indicator illuminates. This means that from this point, only a residual quantity of fuel additive is available for approximately 250 litres of fuel. If the fuel additive tank is not refilled, the MIL illuminates and the fuel additive injection process is stopped.
Service instructions
• The fuel additive pump unit is part of the fuel additive tank and must not be renewed separately during servicing.
Injector
E48500
The injector is connected to the fuel additive tank by means of a fuel line.
The fuel additive pump generates pressure in the fuel line. The injector non-return valve opens and fuel additive is fed into the fuel tank.
Lesson 6 – Engine Emission Control DPF with fuel additive system
Component overview – system control
Components of the Bosch system
E70769
1
2
3
4
5
6 7
8 9
10
11
12
DPF exhaust gas temperature sensor 1
DPF differential pressure sensor 2
IAT sensor 3
Tank flap switch and solenoid (in the tank flap) 4
Piezo sensor on the fuel additive pump unit 5
Fuel additive control unit 6
PCM 7
CAN 8
DLC 9
Charge air cooler bypass flap actuator motor 10
Intake manifold flap actuator motor 11
Fuel additive pump 12
DPF with fuel additive system Lesson 6 – Engine Emission Control
Components of the Siemens system
E70774
Catalytic converter exhaust gas temperature sensor
1
DPF exhaust gas temperature sensor 2
DPF differential pressure sensor 3
IAT sensor 4
Tank flap switch and solenoid (in the tank flap) 5
Piezo sensor on the fuel additive pump unit 6
Fuel additive control unit 7
PCM 8
CAN 9
DLC 10
Charge air cooler bypass flap solenoid valve 11
Intake manifold flap solenoid valve 12
Fuel additive pump 13
Lesson 6 – Engine Emission Control DPF with fuel additive system
PCM
During the regeneration phase, the PCM partially assumes control of the system.
During the regeneration phase, completely different parameters are required for engine management. For this reason, the PCM is equipped with an additional data set for the regeneration phase.
The fuel additive system is monitored by a separate fuel additive control unit which communicates with the PCM via the CAN data bus.
The PCM and the fuel additive control unit can be diagnosed by means of the WDS via the DLC connection.
Service instructions
When installing a new PCM or before loading new software as well as when installing a new DPF, always read the instructions in the current Service Literature.
Fuel additive control unit
Installation position
E48493
1
Fuel additive control unit 1
The fuel additive control unit is located under the right-hand rear seat.
Purpose and function
A separate fuel additive control unit is responsible for fuel additive injection. It is connected to the PCM via the CAN data bus.
The fuel additive control unit detects when the vehicle has been refuelled on the basis of various input variables and subsequently controls metering of the fuel tank additives to be injected into the fuel tank.
The fuel additive control unit also features a counter function. Using this counter, the fuel additive control unit calculates the level in the fuel additive tank by recording the frequency with which the fuel additive pump unit is actuated and the duration of these actuations.
DPF with fuel additive system Lesson 6 – Engine Emission Control
As soon as the level in the fuel additive tank drops below a specific, calculated quantity remaining, the engine system fault warning indicator in the instrument cluster is actuated, indicating in this case that the quantity of fuel additive remaining is sufficient for approximately 250 litres of fuel.
This means that in the case of a fuel tank with a capacity of 50 litres, sufficient fuel additive remains available for approximately five complete refuelling operations or, for example, for ten refuelling operations at 25 litres each.
Information concerning the actual quantity of fuel added is sent by the fuel level sensor. With a properly
functioning system, a minimum tank quantity of 5 litres is registered.
If the engine system fault warning indicator illuminates, this is a signal to the driver that they should drive to the nearest Authorised Ford Workshop as soon as possible.
If the driver does not do this, the MIL is set when the fuel additive tank has been emptied completely.
To indicate an empty fuel additive tank, the fuel additive control unit sends the appropriate information via the CAN bus to the PCM, which logs a DTC and, in turn, actuates the corresponding indicator in the instrument cluster, also via the CAN bus.
Note: If one of the previously mentioned lamps illuminates to indicate that the fuel additive tank is empty, the corresponding DTC must be cleared in the fault memory by means of the WDS once the fuel additive tank has been refilled. In addition, the counter must be reset with the help of the IDS.
Note: The fuel additive tank cannot be emptied fully.
Once the quantity remaining falls below 0.3 litres, fuel additive injection ceases (the driver is informed before this occurs by means of the relevant warning indicators).
The residual quantity prevents the fuel additive pump from drawing in air, which could result in incorrect quantities of fuel additive being metered.
Effects of faults
If a damaged fuel additive control unit means that fuel additive can no longer be added to the fuel, then the DPF can no longer be systematically regenerated. The result is a blocked DPF.
Diagnosis
The fuel additive system is a stand-alone system controlled by the fuel additive control unit.
The fuel additive control unit detects faults in the fuel additive system and sends these via the CAN bus.
The PCM registers the CAN fault data from the fuel additive control unit and subsequently logs a corresponding DTC.
Faults in the fuel additive system can lead to
illumination of both the engine system fault warning indicator and the MIL.
In the event of CAN communication failure, the MIL is also actuated.
Possible fault codes: P2584, P2585, U0118
Fuel additive pump unit
Function
E48499
3 2
1
Connection to the fuel tank 1
Fuel additive pump 2
Piezo sensor 3
The fuel additive pump unit consists of the fuel additive pump and a two-piece piezo sensor.
The internal piezo sensor can only detect when the fuel additive tank is empty. In conjunction with the counter of the fuel additive control unit, this device therefore makes doubly sure that an empty fuel additive tank can be detected.
Note: There are plans to enable the external piezo sensor to detect the precise level and these will be implemented at a later date.
Lesson 6 – Engine Emission Control DPF with fuel additive system
The external piezo sensor establishes the changing viscosity of the fuel additive affected by the ambient temperature and sends this reference value to the fuel additive control unit.
On the basis of this input signal, the fuel additive control unit is able to precisely determine the injection time for the fuel additive.
The fuel additive pump is actuated by the fuel additive control unit using pulse width modulation and supplies the injector on the fuel tank with a precise quantity of fuel additive due to its defined stroke.
Tank flap switch
Installation position
E51571
1
2
Solenoid (in the tank flap) 1
Tank flap switch (reed contact) 2
The tank flap switch is incorporated into the fuel tank filler shroud. The actuating solenoid is located in a bracket at the tank flap.
Purpose and function
The tank flap switch is designed as a reed contact and informs the fuel additive control unit when the fuel tank is filled.
However, the fuel additive control unit only registers that refuelling has taken place if detected by the fuel level sensor in addition to the tank flap switch signal and if the vehicle speed is less than 3 km/h.
If a clear signal is received from the tank flap switch as a result of opening and closing the tank flap and if an increase in the fuel quantity (differential quantity) of at least 5 litres is detected in the fuel tank once the ignition has been turned on, the fuel additive control unit assumes that refuelling has taken place.
The fuel additive control unit calculates the fuel additive quantity to be injected according to the differential quantity calculated, and activates the fuel additive pump.
Activation/metering is performed as soon as the vehicle exceeds a speed of 40 km/h or, if this speed is not reached, 4 minutes after the engine is first started.
Note: After the fuel additive tank has been filled (as part of a scheduled service), the counter in the fuel additive control unit must be reset. It can be reset by opening and closing the tank flap in a certain way and use should be made of this feature (see the current Service Literature). Resetting the counter via the tank flap switch is not possible if either the engine system fault warning indicator or the MIL has illuminated as a result of the fuel additive tank becoming empty. In this case, the counter must be reset with the help of the IDS.
When the tank flap is closed, the tank flap switch is open.
Effects of faults
If the signal from the tank flap switch fails, small refuelling quantities (below 10 litres) cannot be detected.
The software in the fuel additive control unit has been designed to only allow fuel additive to be injected in the case of a missing signal from the tank flap switch if the refuelling quantity is at least 10 litres.
The reason for this is that, in the worst case scenario, the vehicle may, for example, have been rolled onto a slope with the "ignition OFF". Then, when the ignition is next switched on, the fuel additive control unit could register an increased quantity of fuel via the fuel level sensor and might misinterpret this as a refuelling operation. To prevent fuel additive from being injected unnecessarily, if the tank flap switch is faulty the fuel level difference is increased from at least 5 litres to a minimum of 10 litres.
If the signal fails, the engine system fault warning indicator is actuated.
DPF with fuel additive system Lesson 6 – Engine Emission Control
Exhaust gas temperature sensor(s)
Installation position
E48497
The Bosch system
• has just one exhaust gas temperature sensor. This is located directly in the oxidation catalytic
converter/DPF unit upstream of the DPF.
The Siemens system
• has a catalytic converter exhaust gas temperature sensor and a diesel particulate filter exhaust gas temperature sensor.
Purpose and function
The exhaust gas temperature of at least 450 °C to 550
°C required for burning off the diesel particulates is detected by the sensor(s) and transmitted to the PCM.
The exhaust gas temperature input variable is used for calculation purposes by the PCM, which also takes other parameters into account.
Depending on the exhaust gas temperature calculated, the PCM decides whether or not the regeneration process can be initiated.
Through the arrangement of the two sensors, the exhaust gas temperature required for regeneration can be adjusted and monitored very precisely.
The regeneration process cannot be terminated unless a minimum temperature of 450 °C is reached and maintained.
Effects of faults
Bosch system:
• In the event of a fault, the PCM reverts to a substitute value. The substitute value is calculated on the basis of:
– coolant temperature, – engine speed, – engine load.
Siemens system:
• If a fault occurs in one of the two sensors, the value of the other exhaust gas temperature sensor is used by the PCM.
• If both the sensors are defective, a substitute value is calculated.
Diagnosis
The following checks are carried out:
• short and open circuit (by means of a limit range check),
• logical rise/fall rate of the signal, by which means intermittent errors (e.g. loose connector contact) are determined,
• plausibility (after engine start-up, a certain
temperature increase is expected by the PCM within a certain period).
A faulty sensor has no direct influence on exhaust emissions. As regeneration is, however, significantly impaired and clogging of the DPF is possible, the MIL is set in the event of a fault.
Lesson 6 – Engine Emission Control DPF with fuel additive system