Schematic diagram
Key
- "a" electrical links
- "A" additive under pressure
- "B" additive
- "C" diesel
| reference | designation | electrical diagram correspondence |
|---|---|---|
| 1 | Instrument panel | 0004 |
| 2 | built-in systems interface | BSI1 |
| 3 | engine ECU | 1320 |
| 4 | fuel filler cap | - |
| 5 | Fuel tank | - |
| 6 | fuel tank unit | 1211 |
| 7 | fuel gauge | 4315 |
| 8 | additive tank | |
| 9 | fuel additive pump | 1283 |
Role
The fuel additive function keeps the particle filter operational by aiding the combustion of the captured particles, performing the following actions
- Lowering the temperature of combustion of the particles to 450°C (instead of 550°C)
- Impregnating the particles that are gathering in the combustion chamber
- Spreading the combustion of the particles
Performance of the fuel additive function
Engine ECU
The engine ECU receives the information on the amount of fuel put in the vehicle, via the BSI, from the following components
- Fuel gauge
- Wheel speed sensors
Depending on the quantity of fuel put in, the engine ECU takes the following actions
- To determine the quantity of additive to be injected into the fuel tank
- To control the fuel additive pump
The engine management ECU sends a request for an addition of additive of a total volume broken down into requests for one or more volumes of between 1600 and 1632 mm³ to the fuel additive pump, via the intermediary of the built-in systems interface
The engine ECU records in memory the weight of additive that is accumulated in the particle filter
The engine ECU authorises or prohibits the applying of additive, as a function of the following parameters
- State of the additive pump
- Level of additive remaining
- State of clogging of the particle filter
- Fuel gauge state
NoteThe engine ECU sends an alert on the risk of clogging of the particle filter and on the level of additive being insufficient, as a function of the quantity of additive injected and of the weight of additive accumulated in the particle filter
Fuel additive pump
The fuel additive pump injects the precise quantity of additive under pressure, as requested by the engine ECU, into the fuel tank
NoteThe injection pressure of the additive is fixed by an injection valve calibrated to 0,230 ± 0,05 bar (relative pressure)
The additive pump sends to the engine ECU, via the BSI, the following information
- Status of additive system (diagnosis of the additive system)
- Quantity of additive actually added
Built-in systems interface (BSI1)
Role of the BSI
- To memorise faults and to command alerts sent to the instrument panel
- To receive and transmit to the engine ECU information on the quantity of fuel put in
- To serve as a bridge between the engine ECU and the fuel additive pump
When the vehicle is stationary (wheel speed sensor information) and the ignition switched off; the BSI1 memorises the level of fuel present in the tank
When the ignition is switched on again and the vehicle starts moving, the BSI1 acquires and compares the level of fuel with the latest value memorised. if the new value is higher, the BSI1 transmits to the engine ECU the quantity of fuel that has been added
The BSI receives the following information from the engine ECU
- Minimum fuel additive level warning
- Risk of particle filter clogging
The BSI sends the following information from the engine ECU
- State of the additive pump
- Fuel gauge state
Conditions for use of the fuel additive function
The engine controlled ECU controls the fuel additive pump when the following conditions met
- Vehicle speed above 40 km/h or last fuel addition over 300 seconds
- Internal combustion engine running
- Starter switch in the ignition positive position
- Adequate additive level
NoteWhen one of the necessary parameters disappears during the additive injection, the operation continues until the end
Learning / initialisation
The fuel additive function is subject to personalised maintenance