Fuel line 2
Non-return valve 3
Fuel vaporiser 4
Centring 5
Fuel outlet bore 6
Electrical connection for glow plug 7
Main oxidation catalytic converter 8
DPF with integrated oxidation catalytic converter 9
Lesson 6 – Engine Emission Control Fuel vaporiser system
NOTE: At the time of going to print, the fuel vaporiser system is only planned for the 2.4L Duratorq-TDCi in the 2006.5 Transit.
For space reasons, the coated DPF of the 2.4L Duratorq-TDCi (Puma) diesel engine is located far behind the main oxidation catalytic converter. The exhaust gas temperature (approx. 600 °C) generated by engine-based measures for active regeneration of the DPF would cool too rapidly before the DPF is reached.
Active regeneration of the DPF would therefore not be possible.
To attain the necessary exhaust gas temperature for active regeneration, a fuel vaporiser system is installed here.
With the help of the fuel vaporiser system, vaporised fuel is injected to the exhaust tract. The vaporised fuel reacts in the second oxidation catalytic converter, which is located immediately upstream of the DPF. This second oxidation catalytic converter and the DPF are contained in a single housing.
Through the reaction of the vaporised fuel in the second oxidation catalytic converter, the exhaust gas
temperature of around 600 °C required for burning off the trapped diesel particulates is attained.
The fuel vaporiser system is actuated by the PCM under the following conditions:
• The trapped diesel particulates must be burned off with the aid of an active regeneration process.
• The exhaust gas temperature upstream of the DPF must be at least 205 °C.
The fuel vaporiser system is activated during the entire active regeneration process (approx. 10 - 15 minutes).
Service instructions
After working on the fuel vaporiser system (e.g. after renewing the fuel vaporiser system fuel pump or one of the fuel lines), the system must be bled.
After cleaning the fuel system (e.g. due to incorrect refuelling of the vehicle with petrol), the fuel vaporiser system must also be cleaned and then bled.
In this regard, always refer to the instructions in the current Service Literature.
Fuel vaporiser system fuel pump
Purpose and function
E98544
The fuel vaporiser system fuel pump is a reciprocating piston pump. The pump stroke is generated
electromagnetically.
All cavities are filled with fuel in currentless state. When the solenoid coil is energised, the solenoid armature pushes the pump plunger against a spring. The pump plunger opens a non-return valve in the pump and expels the fuel. The pump plunger simultaneously closes the bores to the pump chamber. At the same time, the armature chamber is filled with new fuel. If the power is switched off, the spring pushes the solenoid armature and the pump plunger back. This creates a vacuum and the fuel enters via the bore.
The pump delivers fuel to the fuel vaporiser for the duration of the regeneration process.
The fuel pump is actuated by the PCM during active regeneration with a frequency of 6 Hz.
Service instructions
After installing a new fuel vaporiser system fuel pump, the fuel vaporiser system must be bled. In this regard, always refer to the instructions in the current Service Literature.
Effects of faults
If the pump is defective, active regeneration can no longer be carried out. The result is a blocked DPF.
Fuel vaporiser system Lesson 6 – Engine Emission Control
Fuel vaporiser
Purpose and function
E97163
1 2
4 3
5
Fuel vaporiser 1
Glow plug 2
Fuel vaporiser chamber 3
Fuel outlet bore 4
Non-return valve 5
At the start of the regeneration process, the glow plug in the fuel vaporiser is actuated by the PCM.
A few seconds later, the fuel vaporiser system fuel pump delivers fuel to the fuel vaporiser chamber.
The delivered fuel flows past the heated glow plug, vaporising in the process. The vaporised fuel then flows into the exhaust tract via the outlet bore.
The non-return valve ensures the necessary pressure and prevents the fuel line draining. The fuel is admitted into the fuel vaporiser chamber at a pressure of less than 2 bar.
Lesson 6 – Engine Emission Control Fuel vaporiser system
Tick the correct answer or fill in the gaps.
1. What is the fuel additive used for?
a. To enhance the performance of the engine.
b. To lower the NOX emissions during the regeneration process.
c. To support the combustion of HC emissions inside the engine.
d. To lower the combustion temperature for the deposited diesel particulates.
2. What is the advantage of the coated DPF?
a. No interventions by the engine management system are required.
b. Active regeneration can take place at 300 °C.
c. The fuel additive tank is designed with a large enough volume so that no fuel additive needs to be topped up for the service life of the vehicle.
d. No fuel additive is required.
3. What must be performed on vehicles with coated DPF after each oil change?
a. A reset of the parameters for the soot load of the DPF.
b. A reset of the parameters for the oil quality calculation.
c. A reset of the differential pressure sensor parameters.
d. A visual inspection of the DPF for signs of overheating.
4. The fuel vaporiser system
a. pumps fuel from the EVAP (Evaporative Emission) canister directly into the exhaust tract.
b. injects vaporised fuel into the exhaust tract.
c. injects vaporised fuel directly into the engine cylinder during the exhaust stroke.
d. injects vaporised fuel directly into the intake tract.
Test questions Lesson 6 – Engine Emission Control
Lesson 1 – General Information 1. b
2. c 3. d 4. c
Lesson 2 – Fuel System 1. b
2. a 3. b 4. c
Lesson 3 – Powertrain Control Module (PCM) 1. c
2. a 3. d 4. c
Lesson 4 – Sensors 1. c
2. a 3. b 4. c
Lesson 5 – Actuators 1. d
2. c 3. a 4. c
Lesson 6 – Engine Emission Control 1. d
2. d 3. b 4. b
Answers to the test questions