Range Rover Evoque: Fuel Tank and Lines - System Operation and Component Description

Control Diagram

NOTE: A = Hardwired

1. Battery
2. Battery Junction Box (BJB)
3. Fuel Pump Driver Module (FPDM)
4. Fuel pump delivery module
5. Engine Control Module (ECM)
6. Central Junction Box (CJB)

System Operation

OPERATION

The 2.0L GTDi fuel system uses a returnless fuel system. The fuel pump operation is regulated by the FPDM (fuel pump driver module), which is controlled by the ECM (engine control module). The FPDM regulates the fuel flow and pressure delivered to the engine mounted High Pressure (HP) fuel pump by controlling the operation of the fuel pump using PWM (pulse width modulation) output.

The pump operation is controlled by the ECM which uses signals from the Low Pressure (LP) fuel sensor to regulate the pump operation to maintain the optimum fuel pressure and flow.

Two fuel level sensors are connected to the CJB (central junction box). The CJB monitors the outputs from these sensors to determine the fuel level remaining in the fuel tank and to display the fuel level in the instrument cluster.

Component Description

DESCRIPTION

Fuel System Schematic Diagram

1. To fuel rail
2. High Pressure (HP) fuel pump
3. Low Pressure (LP) fuel pressure sensor
4. Jet pump
5. Fuel filter
6. Pressure relief valve
7. Fuel pump module assembly
8. Right Hand (RH) fuel level sensor
9. Left Hand (LH) fuel level sensor

FUEL TANK

1. Fuel delivery module flange
2. Fuel pick-up - LH side
3. LH fuel level sensor float
4. LH fuel level sensor
5. Liquid Vapor Separator (LVS)
6. Fuel delivery module (incorporating RH fuel level sensor & RH venturi)
7. Fuel fired booster heater feed pipe (if fitted)
8. Fuel vapor purge pipe
9. Fuel feed pipe

The fuel tank is manufactured using six-layer co-extruded blow-molding technology providing both high mechanical strength and complete emissions integrity and is mounted under the rear seat floor pan, forward of the rear suspension.

The fuel tank has a capacity of 70 liters (18.5 US gallons).

The tank is a saddle tank design which is secured to the vehicle floor pan with two straps which are bolted in position. The fuel filler neck is produced from stainless steel.

The tank contains a fuel pump delivery module which collects fuel from both sides of the tank. The pump supplies the engine's fuel demands while also supplying the fuel to power the two venturi. The rapid flow of fuel through the venturi nozzle creates a depression which draws fuel back across the saddle into the pump side of the tank and fills the swirl pot.

The internal bracket incorporates the Liquid Vapor Separator (LVS) and also allows for the attachment of the LH (left-hand) fuel pick-up and the LH fuel level sensor. The LVS collects liquid fuel and returns it back to the tank via a Fuel Limit Vent Valve (FLVV).

To meet ORVR (on-board refueling vapor recovery) requirements, the fuel tank and associated components are designed to minimize fuel vapor loss during refueling. This is achieved by preventing fuel vapor from the fuel tank venting directly to the atmosphere. Instead fuel vapor is directed into the EVAP (evaporative emission) canister where it is stored before being purged at intervals to the engine's intake manifold.

Refer to: Evaporative Emissions (303-13 Evaporative Emissions - GTDi 2.0L Petrol, Description and Operation).

FUEL PUMP DELIVERY MODULE

1. Flange
2. Electrical connector
3. Breather hose connection
4. Fuel tank vapor connection
5. Fuel fired booster heater feed connection
6. Fuel feed pipe connection
7. RH venturi
8. Swirl pot
9. Fuel inlet filter
10. RH fuel level sensor float
11. RH fuel level sensor

The fuel pump delivery module is located inside the fuel tank and comprises three main components; a fuel pump, a remote fuel pick-up and a top flange assembly.

Fuel Pump

The fuel pump is a rotary vane type pump, which operates in the fuel delivery module located in the RH (right-hand) side of the tank. A venturi transfer pump is also located in the RH side of the tank. The fuel pump module is secured in the tank with a bayonet style locking ring that is welded into the tank structure. The fuel pump module has an integral top plate for external pipe connections and also an electrical connector.

The electric pump is located in a plastic swirl pot which collects fuel from the bottom of the fuel tank via a filter. The swirl pot retains fuel and ensures that fuel is always available for the pump to draw from.

The fuel level sensor for the RH side of the tank is attached to the outside of the swirl pot.

The fuel delivery module is a serviceable component and is accessed via the top flange.

Remote Fuel Pick-Up and Level Sensor Assembly

The remote fuel pick-up is located in the LH side of the fuel tank. The pick-up arm assembly is attached to the tank internal bracket which holds the pick-up at the bottom of the tank.

The fuel pump system incorporates two jet pumps. One jet pump is integrated into the fuel pump and draws fuel from the RH side of the tank into the swirl pot. The other jet pump is located on the fuel delivery module on the RH side of the tank. A pick-up pipe located in the LH side of the tank allows fuel to be drawn over from the LH side of the tank, delivering fuel into the swirl pot. The jet pumps operate on a venturi effect created by the fuel passing through the jet pump.

The fuel level sensor for the LH side of the tank is attached to the pick-up arm assembly, which is secured to an internal bracket. The fuel pick-up and level sensor are serviceable components and access is by removal of the top flange on the RH side of the fuel tank.

Top Flange Assembly

The top flange is located on the top RH side of the fuel tank. The flange assembly is sealed in the tank with a sealing ring. A locking ring secures the flange assembly in the tank and requires a special tool for removal.

The outer surface of the top flange has four outlets with quick-fit connections and an electrical connector. One connection is the pressure outlet to the HP fuel pump mounted on the engine. The second outlet is the fuel supply to the Fuel Fired Booster Heater (FFBH) (if fitted). The third connection is for the fuel tank breather hose and the fourth connection (on ROW vehicles only) is the evaporative emission vapor outlet to the charcoal canister.

The electrical connector is located adjacent to the fuel tank breather outlet connection and provides the electrical interface to the fuel pump and the level sensors.

FUEL PUMP DRIVER MODULE (FPDM)

The FPDM is located in the LH rear of the luggage compartment. The module is attached to a bracket suspension turret and secured with two bolts.

The operation of the fuel pump is regulated by the FPDM which is controlled by the ECM. The FPDM regulates the flow and pressure supplied by controlling the operation of the fuel pump using a PWM output.

The FPDM is powered by a fused supply from the fuel pump relay in the BJB (battery junction box). The fuel pump relay is energized when the driver's door is opened or power mode 9 engine crank is initiated using the stop/start button. The FPDM supplies power to the fuel pump and adjusts the frequency of the PWM power output to control the speed of the fuel pump and consequently the pressure and flow of fuel in the fuel delivery line to the HP fuel pump.

The PWM signal from the ECM tells the FPDM the required speed for the fuel pump output. The on time of the PWM signal represents half of the fuel pump speed, for example; if the PWM signal on time is 50%, then the fuel pump is run at 100%.

The FPDM will only energize the fuel pump if it receives a valid PWM signal, with an on time of between 4% and 50%. To switch the fuel pump off the ECM transmits a PWM signal with an on time of 75%.

The output pressure from the fuel pump is controlled in line with changes of engine demand and temperature. The ECM monitors the input from the LP fuel sensor and adjusts the fuel pump output as required to maintain a nominal output pressure of 4.5 Bar (65.3 lbf/in

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