Zero Volume Adaptation

The zero volume adaptation is a continual learning process. This learning process is required to enable precise pre-injection for each individual fuel injector. Accurate metering of the very low pre-injection volume is necessary for the fulfilment of exhaust emission regulations.

Zero volume adaptation must be carried out on a continual basis due to the volume drift of the fuel injectors.

At each cylinder, a small amount of fuel is injected during overrun mode. This volume continues to increase until a slight increase in engine speed is detected by the digital diesel electronics.

The digital diesel electronic is thus able to detect when the respective cylinder begins to work. The volume of fuel injected during zero volume adaptation is used by the digital diesel electronics as a value for the characteristic map of pre-injection.

Zero volume adaptation takes place alternately from one cylinder to the next during the overrun phase at engine speeds from 1500 to 2500 RPM and with the engine at operating temperature.

Zero volume adaptation has no influence on fuel consumption as only very small quantity of fuel (about 1mm3) is injected at one cylinder at a time.