CDI main injection function

Calculation of the main injection quantity is split into two parts:

 Calculation of the injection time

 Calculation of the duration of injection

Start of actuation of main injection

Start of actuation is determined on the basis of the operating point and adjusted on the basis of the atmospheric pressure, the coolant temperature and the intake air temperature. The base value is calculated from different maps in line with the actuation of preinjection. The reason for this dependence on preinjection is the different combustion method with or without preinjection.

Actuation period of main injection

The difference of the total specified quantity and preinjection forms the main injection quantity. In this simplest case, this is converted by means of the conversion map into an actuation period matching the rail pressure during the moment of injection.

An important point to note here is that, if preinjection has been activated, a different duration of actuation is required than is the case without preinjection (as a result of the pressure variations which this produces). This difference is achieved by an appropriate control system which appropriately evaluates also the transition from zero load to part load and activates or deactivates preinjection sequentially.