Flow chart
Direction of fuel circulation (as per arrows)
| reference | designation | part number in the electrical diagrams |
|---|---|---|
| 1 | valve SCHRADER | |
| 2 | pulsation damper | |
| 3 | fuel supply pipe (low pressure) | |
| 4 | low pressure inlet clickfit union | |
| 5 | high pressure outlet union | |
| 6 | high pressure fuel pump | |
| 7 | high pressure fuel supply pipe | -- |
| 8 | fuel high pressure common injection rail | -- |
| 9 | petrol injectors | 1131 - 1132 - 1133 - 1134 |
| 10 | high pressure fuel sensor | 1321 |
| 11 | high pressure fuel regulator | 1322 |
| 12 | fuel outlet union (towards the low pressure fuel circuit) | -- |
| a | to the fuel supply pipe (fuel tank) |
Fuel tank
The fuel tank is identical to that used on conventional petrol versions
Stopping the supply to the low pressure pump
The airbag units incorporate the function which stops the supply to the low pressure pump (discontinuation of the inertia switch)
If a pyrotechnic component is deployed, the fuel supply is cut off (the double relay is incorporated in the engine fusebox)
Starting the engine
- Switch off the ignition
- Switch on the ignition
Booster pump (low pressure) (1211)
Role
Role of the booster pump
- To provide the pressure required in the low pressure circuit
- To supply fuel to the high pressure pump
Constituent parts of the tank unit/fuel pump module
- Booster pump (low pressure)
- Fuel filter (can't be disassembled)
- The gauge function
- Fuel pressure regulator
Description
Tank unit/fuel pump module
(12) fuel filter (can't be disassembled)
(13) fuel pressure regulator
The fuel filter is incorporated in the tank unit/fuel pump module (can't be disassembled)
The booster pump is supplied with 12 volts through the double injection relay in the following cases
- As soon as the engine is switched on, for 2 to 3 seconds
- Engine running
The double relay is incorporated into the engine relay unit
Fuel pressure regulator incorporated into the sender unit (low pressure fuel circuit)
Electrical special features
Control
- Injection ECU
- Injection double relay (the double relay is incorporated in the engine fusebox)
Allocation of channels of connector
- Terminal 1: not used
- Terminal 2: not used
- Terminal 3: scavenge pump power supply (+ 12 volts)
- Terminal 4: booster pump earth
- Terminal 5: fuel gauge earth
- Terminal 6: fuel level signal
Fuel pressure regulator (low pressure fuel circuit)
The low pressure regulator controls the pressure of the fuel in the low pressure circuit
Circuit pressure: + 5 bars
The low pressure regulator is fixed on the tank unit/fuel pump module
Pulsation damper
The role of the pulsation damper is to absorb the waves caused by the opening and closing of the injectors
The pulse damper is located on the front right hand wheelarch
High pressure fuel pump
Role
Role of the high pressure fuel pump (SIEMENS with 3 radial pistons and diaphragm)
- To supply high pressure fuel
- To supply the diesel injectors through the high pressure common injection rail
Description
(6) high pressure fuel pump
(14) click-on connector: low pressure inlet
(15) high pressure outlet union (to the common injection rail)
(16) drive cam
The high pressure pump is driven by the inlet camshaft
Special features
- Keyway drive system
- Fuel high pressure pump with 3 axial pistons, lubricated for life
- The fuel high pressure pump has 2 chambers (one for the petrol, the other for the lubricating oil for the mechanical parts) isolated by an elastic diaphragm
- The high pressure is created by the action of the pistons on the diaphragm, via the cushion of oil
- An internal valve limits the pressure in the high pressure lines (specific rating = 130 bars)
- An expansion chamber absorbs the volume expansion of lubricating oil
The fuel high pressure pump used is marketed by the Replacement Parts dept.: low pressure union - high pressure outlet union - drive cam
WarningNo intervention is permitted on the high pressure fuel pump
Fuel high pressure common injection rail
Role
Role of the high pressure fuel common injection rail
- To store the amount of fuel required by the engine regardless of the operating phase
- To damp the pulses created by injections
- To connect the components of the high pressure circuit
Components connected to the fuel high pressure common injection rail
- High pressure fuel supply pipe
- Petrol injectors
- High pressure fuel sensor
- High pressure fuel regulator
Description
(8) fuel high pressure common injection rail
The fuel high pressure common injection rail is made of aluminium
Location
The common injection rail located between the high pressure pump and the diesel injectors is mounted on the cylinder head
High pressure fuel regulator (1322)
The high pressure fuel is controlled by the high pressure fuel regulator
The high pressure fuel varies between 30 and 100 bar
Petrol injectors (1131, 1132, 1133, 1134)
(9) petrol injectors
"b": high pressure fuel supply (fuel high pressure common injection rail)
"c": electrical connector
The injectors allow the quantity of fuel to be measured out
The petrol injectors are similar to the injectors used in indirect injection systems, but are strengthened for high pressure fuel
The petrol injectors are controlled electrically by the injection ECU
WarningThe petrol injectors are controlled with a voltage of 77 volts, do not interfere with the electrical harness when the engine is running