General description

GENERAL DESCRIPTION

The EDC-15C Common Rail is a high pressure electronic injection system for fast diesel engines with direct injection.

The main features are:

• availability of high injection pressures (1350 bar)
• possibility of modulating these pressures between 150 bar up to the maximum operating pressure of 1350 bar, regardless of the engine speed and load
• capability of operating at high engine speeds ( up to 6000 rpm).
• injection control precision (advance and length of injection)
• reduction of consumption levels
• reduction of emissions.

The main functions of the system are mainly the following:

• fuel temperature control
• engine coolant temperature control
• injected fuel quantity control
• idle speed control
• fuel cut-off during deceleration
• cylinder balancing at idle speed control
• “anti-sawing” control
• exhaust smoke control during acceleration
• exhaust gas re-circulation control (E.G.R.)
• maximum torque limiting control
• maximum engine speed limiting control
• glow plug control
• climate control system engagement control (where fitted)
• auxiliary fuel pump control
• cylinder position control
• main and pilot injection advance control
• injection pressure closed loop control
• electric balance control
• supercharging pressure control
• self-diagnostics
• connection with Alfa Romeo CODE control unit (Immobiliser).

SYSTEM FUNCTIONS

The Common Rail system makes pre-injection (pilot injection) possible before the T.D.C. with the advantage of reducing the derivative of the pressure in the combustion chamber, reducing the combustion noise typical of direct injection engines.

SYSTEM OPERATING LOGIC

Self-diagnostics

The control unit self-diagnostic system checks the signals leading from the sensors comparing them with the permissible limit data:

• fault signalling at starting
  • warning light on for 4 seconds indicates the test phase
  • warning light off after 4 seconds indicates no fault to components that may change the values set down by anti-pollution regulations
  • warning light on after 4 seconds indicates a fault.
• fault signalling during operation
  • warning light on indicates a fault
  • warning light off indicates no fault to components that may change the values set down by anti-pollution regulations.
• recovery
  • the control unit defines the type of recovery depending on the faulty components
  • the recovery parameters are managed by normally operating components.

The control unit controls the amount of fuel injected, adjusting the line pressure and injection times.

The information the control unit processes to control the amount of fuel to be injected is the following:

• engine rpm
• coolant fluid temperature
• supercharging pressure
• air temperature
• quantity of intake air
• battery voltage
• fuel oil pressure
• accelerator pedal position.