Fuel Delivery: Operation: Pre-injection: Notes
WARNING: This page is about a different car, the 2006 Dodge Sprinter. However, it is still accessible from the selected car via links, so may be relevant.
The purpose of the pre-injection function is to reduce noise and pollutants. The coolant temperature, charge air temperature and atmospheric pressure are use to correct the quantity of pilot injection. The quantity of pilot injection now determined is deducted from the quantity of main injection in order to establish whether sufficient quantity is available for the following main injection.
The rail pressure is chosen sufficiently high so that a minimum quantity is injected. If the quantity of main injection is too small the pilot injection is switched off by the ECM.
The start of actuation of pilot injection is calculated dependent on operating point, the following data being taken into account: