2
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Fuel rail pressure (FRP) sensor
3
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Fuel pressure regulator
General
A Siemens common rail fuel injection system is used on the 1.8L Duratorq-TDCi (Kent) diesel engine with stage 4 emission level (vehicle identification number (VIN) plate emission level code: S).
Within the fuel pump there is an integral fuel transfer pump which draws the fuel from the fuel tank to the fuel pump.
A fuel metering valve is located in the supply port to the high-pressure chamber of the fuel pump. The fuel metering valve varies the quantity of fuel supplied to the fuel rail and fuel injector(s), in relation to the driving conditions.
The fuel is supplied at high-pressure to the fuel rail and to the fuel injectors ready for injection. Depending on engine operating conditions, the fuel injection pressure varies between 200 bar and 1600 bar.
Fuel system pressure is measured using an FRP sensor located in the fuel rail. The FRP sensor converts the fuel system pressure into a voltage signal. This voltage signal acts as an input signal to the powertrain control module (PCM) for calculation of the fuel injection quantity.
The PCM calculates the time of fuel injection and the fuel injection quantity depending on various input variables.
The specified quantity of fuel is injected into the respective combustion chamber through the piezo-electrically actuated fuel injector(s).
The excess fuel is returned to the fuel tank through the fuel return line.
The fuel pressure regulator on the high-pressure outlet of the fuel pump regulates the fuel pressure in the fuel rail.
Fuel pump
1
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Fuel pump fuel return port
2
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Fuel pressure regulator
3
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High-pressure fuel supply line port
4
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Fuel pump fuel supply port
The fuel pump is driven clockwise at half the engine speed by the timing belt.
The fuel pump has three pump elements, each offset from each other by 120 degrees.
The fuel transfer pump is incorporated into the fuel pump and is located on the drive flange. The fuel transfer pump is a vane type pump.
The fuel metering valve is actuated by the PCM using pulse width modulation.
The fuel pressure regulator is located on the fuel pump. The fuel pressure regulator operates electromagnetically and is actuated by the PCM.
Fuel rail
CAUTION:The FRP sensor must not be detached or removed from the fuel rail. Failure to follow this instruction may result in foreign material ingress to the fuel injection system.
The fuel rail is made from forged steel and is retained by a support bracket located on the cylinder block.
The fuel is delivered to the fuel rail by one high-pressure fuel supply line from the fuel pump.
From the fuel rail, the fuel travels through high-pressure fuel supply line(s) to the fuel injector(s).
Fuel injectors
1
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Fuel injector electrical connector
3
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High-pressure fuel supply port
5
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Fuel injector retaining clamp bolt
6
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Fuel injector retaining clamp
7
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Fuel injector fuel return line retaining clip
NOTE:New fuel injector fuel return line retaining clips must be installed, when the fuel injector fuel return line has been removed from the fuel injectors.
The fuel injector(s) are offset by 20 degrees from vertical in the cylinder head upper section and are attached by means of retaining clamps.
The fuel injector(s) are sealed from the combustion chamber by means of a copper sealing washer located between the fuel injector and the cylinder head. A new sealing washer must always be installed when carrying out installation work.
The fuel injectors are controlled directly by the PCM.
The fuel return line(s) are attached to the fuel injectors by using the fuel injector fuel return line retaining clips and are connected in parallel.
