Fuel injectors

Each fuel injector is activated by its own output stage. This type of injection is called fully sequential fuel injection.

Fully sequential fuel injection

Fully sequential fuel injection offers the following advantages:

• Improved fuel trim for each individual cylinder
  
• Immediate adaptation of the injection timing to the current engine operating status
  
• Cylinder-selective injection correction under changing engine load
  
• Cylinder-selective deactivation (e.g. with faulty ignition coil)
  
• Diagnosis of each individual fuel injector
  
• If an output stage malfunctions, the engine can continue to be operated on the remaining cylinders in limp-home mode
  

Function

Each fuel injector is activated by its own output stage. This ensures that the supply of fuel is the same to all cylinders. This in turn makes possible a uniformly good fuel trim for all the cylinders. The point of injection can be optimally adapted to the currently prevailing operating conditions, for example engine load and speed.

With fully sequential fuel injection, fuel is injected only once per camshaft revolution. This reduces any variation in the amount of fuel delivered as a result of component tolerances. Added to this, the idle quality is also improved as the energization and de-energization times at the fuel injectors are reduced. Fuel consumption is also slightly lower.

The injection timing can be adapted individually per cylinder while driving as the result of sudden acceleration or after deceleration. This achieves improved response characteristics of the engine.

Diagnosis

If faults occur at the fuel injectors, corresponding faults are stored in the fault memory of the DME control module. A corresponding diagnostic program enables each fuel injector to be function tested.