Self Study Program 227 – 3.3L V8 TDI Common Rail Injection System Construction

VAG SSP 227 . With its TDI engines, Audi AG has been a leader in diesel development since 1989. Its latest technological innovation, the unique V8 TDI bears testimony to this fact.

Common Rail
A new injection system for the V8 engine

Given that it can be integrated in existing engine concepts relatively easily, the common rail system is a new alternative injection system for modern diesel engines. As with any injection system, the common rail serves the following tasks:

  • Supplying the diesel engine with fuel
  • Generating a high pressure for the injection cycle and distributing fuel to the cylinders
  • Injecting a precisely calculated quantity of fuel into the cylinders at the right point in time.


  • Introduction
    • Common Rail System
  • Components of the common rail
    Overview of the fuel feed process
    Low-pressure fuel feed
    Roller cell pump
    – Gear type pump
    High-pressure fuel feed
    – High-pressure pump
    – Valve for fuel dosing N290
    – Fuel rail with high-pressure control circuit
    – Regulating valve for fuel pressure N276
    – Fuel pressure sender G247
    – High-pressure circuit
    – Valve-controlled injection unit (injector)
    – Function of injector
  • Engine management
    Mixture formation
    – Commencement of fuel injection
    – End of fuel injection
    – Pre-injection cycle
    – Vacuum control
    – Double flow throttle valve
    System overview
    Function diagram
    Actuators and sensors
    – Hall sender G40
    – Engine speed sender G28
    – Engine control unit J248/J494
    – Fuel temperature sender G81
    – Intake manifold pressure sender G71
    – Fuel bypass valve N312
    – Valve for fuel dosing N290

The Self-Study Programme explains the design and function of new developments! The contents of this SSP are not updated.
Please always refer to the relevant Service Literature for all inspection, adjustment and repair instructions.

Language: English
Format: PDF
Pages: 36

Self Study Program 227 – 3,3 l V8 TDI Common Rail Injection System Construction Features and Functions PDF free online