Fuel Charging and Controls

Fuel Charging and Controls

COMPONENT LOCATION









OVERVIEW
The fuel pump module, located in the fuel tank, is electronically regulated by the Engine Management System (EMS) to provide controlled pressure in the fuel rail For additional information, refer to Fuel Tank and Lines Fuel Tank and Lines.
Supplying the correct amount of fuel as required by the engine at any given moment, eliminates the requirement for additional pipes returning excess fuel to the fuel tank. The benefits of this type of system are:
- Reduced load on the electrical system
- Improved fuel economy
- Eliminates the effects of fuel pressurization and depressurization
- Eliminates the effects of engine-heat causing extra fuel vapor being generated in the fuel tank by returning fuel
Closed-loop Pulse Width Modulation (PWM) control, of the fuel pump module, via the Engine Control Module (ECM) regulates the amount of fuel supplied by the fuel pump to the fuel rail. The ECM receives signals from the combined fuel rail pressure and fuel temperature sensor, located on the fuel rail to indicate the pressure of fuel in the fuel rail. In response to these signals, plus other engine and driver demand signals, the ECM calculates the amount of fuel required and requests the fuel pump module to vary the fuel pump delivery to suit the engine's requirements. For additional information, refer to Electronic Engine Controls - 3.2L Electronic Engine Controls
The fuel pump maintains a fuel rail pressure 3.8 bar above manifold depression under normal operating conditions, though this is programmed to rise to 4.2 bar in response to either:
- cold start conditions, to improve fuel vaporization
- cold fuel conditions, as the colder the fuel the higher its viscosity
The fuel rail has an integrated pulsation damper and a connection for draining the fuel system.
The injectors supplied by the fuel rail; each have 4 micro-nozzles capable of injecting up to 18 mg of fuel under high-load conditions, the injectors also provide precision fueling across all engine speed and load conditions.