Description
Fuel Charging and Controls
Operation of the fuel charging and control system is controlled by the ECM (engine control module). For additional information, refer to Electronic Engine Controls Description
Air Induction System
The air induction system comprises the supercharger and a series of ducts and ports which direct compressed air into the engine. Air is drawn into the engine through the air inlet duct and into the induction elbow at the back of the engine, which houses the electronic throttle. The air is directed through the induction elbow into the supercharger, where it is compressed above atmospheric pressure. The compressed air exits the supercharger through a port in the upper surface and through the charge air ducts into the two intercoolers, one above each cylinder bank.
After compression in the supercharger, the intake air temperature often exceeds 160 °C (320 °F). For this reason the intercoolers are liquid cooled and act as separate air to liquid heat exchanger matrices for each bank of cylinders. The cooled and denser compressed air passes from the intercoolers to the fuel rail adapters and into the engine.
A vacuum operated bypass valve, situated downstream of the throttle body, opens during part throttle operation. This has the effect of recirculating and controlling the compressed air pressure and reducing unnecessary supercharger pumping operation.
Fuel Pump
The high flow rate fuel pump module is mounted in the RH (right-hand) side of the saddle type fuel tank and delivers fuel at variable flow and pressure to the fuel rails, which supply fuel to all fuel injectors. The fuel pump operation is regulated by the FPDM (fuel pump driver module), which is controlled by the ECM (engine control module). For additional information, refer to Fuel Tank and Lines Description
Fuel Pump Driver Module
The FPDM (fuel pump driver module) is used to control the speed of the fuel pump based upon the fuel demand of the engine. The ECM (engine control module) controls the FPDM (fuel pump driver module) in response to inputs from the FRP (fuel rail pressure) sensor, MAP (manifold absolute pressure) sensor, MAF (mass air flow) sensor and the IAT (intake air temperature) sensor. The FPDM (fuel pump driver module) is attached to the RH (right-hand) end of the evaporative emission canister, which is installed on the underside of the center floor pan, above the rear stabilizer bar.
The ECM (engine control module) sends a PWM (pulse width modulation) signal to the FPDM (fuel pump driver module), the frequency of the signal determines the duty cycle of the pump. The PWM (pulse width modulation) signal to the pump represents half the ON time of the pump. If the ECM (engine control module) transmits a 50% ON time this drives the pump at 100%. If the ECM (engine control module) transmits a 5% ON time the FPDM (fuel pump driver module) drives the pump at 10%. The FPDM (fuel pump driver module) will only turn the fuel pump ON if it receives a valid signal between 4% and 50%. When the ECM (engine control module) requires the
fuel pump to be turned OFF, it transmits a duty cycle signal of 75%.
The status of the FPDM (fuel pump driver module) is monitored by the ECM (engine control module). Any errors can be retrieved from the ECM (engine control module) using the Jaguar approved diagnostic system. The FPDM (fuel pump driver module) cannot be interrogated for diagnostic purposes.
Fuel Injectors
Eight, top fed, 12 hole, fuel injectors are installed in the fuel rails. Two O-rings seal each injector to the fuel rails. The fuel jets from the injectors are directed onto the back of the intake valves.
The injectors are electromagnetic solenoid valves controlled by the ECM (engine control module). Each injector contains a solenoid-operated needle valve, which is closed while the solenoid winding is de-energized. The solenoid winding is connected to a power feed from the main relay and to an earth through the ECM (engine control module). The ECM (engine control module) switches the earth to control the opening and closing of the needle valve. While the needle valve is open, fuel is sprayed into the cylinder intake tract onto the back of the intake valves. The ECM (engine control module) meters the amount of fuel injected by adjusting the time that the needle valve is open.
The solenoid winding of the fuel injector has a resistance of 13.8 ± 0.7 ohms @ 20 °C (68 °F).
Electric Throttle
The electric throttle controls the engine torque and is located on the induction elbow at the rear of the engine. Its main components are an electronic throttle control valve, an APP (accelerator pedal position) sensor and the ECM (engine control module).
The APP (accelerator pedal position) sensor determines the driver demand to control throttle opening. This value is received by the ECM (engine control module) and the throttle is then opened to the correct angle by means of an integral electric motor. Sensors in the throttle body are used to determine the position of the throttle plate and the rate of change in its angle. For additional information, refer to Electronic Engine Controls Description
Fuel Rails
Each fuel rail maintains a fuel pressure of typically 4.5 bar (65 lbf/in2), however, this pressure will vary depending on engine requirements; lower at idle, higher at full load. Four fuel injectors are installed in each cylinder head and are connected to the fuel rail. O-ring seals are used to seal the fuel injectors to the fuel rails.
Fuel Pressure Damper
A fuel pressure damper is attached centrally to each of the fuel rails. The damper acts to damp pressure pulses from the fuel pump.
Fuel Temperature Sensor
The fuel temperature sensor is located in the rear of the RH (right-hand) fuel rail. The sensor is a NTC (negative temperature coefficient) sensor, which is connected to the ECM (engine control module) by two wires. For additional information, refer to Electronic Engine Controls Description
Fuel Rail Pressure Sensor
The FRP (fuel rail pressure) sensor continuously monitors the fuel pressure in the fuel rail, this value is used by the ECM (engine control module) to calculate the injector pulse-width required to deliver the correct mass of fuel per injection. The ECM (engine control module) also uses this information to demand a specific fuel flow-rate from the fuel pump via the FPDM (fuel pump driver module). For additional information, refer to Electronic Engine Controls Description