Circuit diagram
Key
- "A" fuel system
- "B" petrol in the tank
- "C" electrical links
| reference | description | electrical diagram correspondence |
|---|---|---|
| (1) | engine fuse and relay box | BFRM |
| (2) | built-in systems interface | BSI1 |
| (3) | engine management ECU | 1320 |
| (4) | petrol injector supply rail | - |
| (5) | petrol injectors (1), (2), (3) | (1331, 1332, 1333) |
| (6) | Fuel tank | - |
| (7) | fuel pump-gauge assembly | 1211 |
Control of the injection
The engine ECU receives and converts the demands from the driver, or from the vehicle (ABS, ESP, automatic gearbox), into information on the necessary torque that is required of the engine
The engine ECU determines the quantity of air that is necessary for providing the engine torque requested
The engine ECU determines the quantity of fuel that is necessary, according to the quantity of air admitted
As a function of the fuel quantity calculated, the engine ECU determines the fuel injection time
To comply with the emission standards, limit the combustion noises and improve the driving performance, the engine ECU determines the time for each injection of fuel during an engine cycle
The engine torque request takes account of a number of corrections (torque absorbed by the alternator, torque absorbed by the air con compressor etc.)
NoteThe injection is sequential but in the starting phase the engine ECU operates the injectors simultaneously (the injectors operate at the same time)
General
Fuel injection pressure being equal, a longer (or shorter) injection time allows more (or less) fuel to be injected
When there is a large engine load need, fuel injection pressure being equal, the fuel injection time is extended to obtain the maximum engine torque
The fuel injection time corresponds to the time during which the engine ECU commands the fuel injectors to be open
Specificities
The fuel injection time is calculated as a function of the following parameters
- Engine speed
- Engine load
- Vehicle speed
- Engine coolant temperature
- Intake air temperature
- Positions of the inlet and exhaust camshaft dephasers
Cutting off the fuel supply in the event of an accident
When a pyrotechnic component is triggered, supply of the fuel pump is cut off by the engine compartment fusebox (BFRM) via the triggering information coming from the airbags ECU
To restart the engine following a fuel supply cut-off
- Switch off the ignition
- Switch on the ignition
- Start the engine
Cutting off the fuel supply in the event of over-revving
In the event of over-revving, the engine ECU orders fuel supply cut-off at 6500 rpm