GF07.16-P-3012IC CDI High Pressure Circuit, Function

GF07.16-P-3012IC CDI High Pressure Circuit, Function

Component Identification:

The high-pressure circuit regulates and stores the fuel pressure required for injection.
The high pressure pump compresses the fuel up to an operating pressure of 1600 bar and pumps the controlled quantity of fuel it into the rail. The fuel flows along the high pressure lines to the individual fuel injectors.

Injected quantity control
Injection quantity control is cylinder-selective and carried out by the CDI control unit (N3/9). For this purpose, either the actuation time for the fuel injectors or the rail pressure can be adapted via the pressure regulator valve or the quantity control valve.

High pressure control
The CDI control unit uses its input signals to determine the actual operating status of the engine (load request) and regulates the rail pressure between around 300 and 1600 bar accordingly.
For rail pressure adaptation, a control current, dependent on performance mapping, is applied to the quantity control valve or the pressure regulator valve by the CDI control unit, until the target pressure is adjusted in the rail.

The rail pressure sensor measures the current rail pressure and sends the corresponding voltage signal to the CDI control unit.

Rail pressure regulation via pressure regulator valve
The rail pressure is regulated via the pressure regulator valve up to 30 seconds following engine start and up to a fuel temperature of 20 °C.

The fuel is heated by rail pressure regulation via the pressure regulator valve.

Rail pressure regulation via quantity control valve
Rail pressure regulation via the quantity control valve takes place from 30 seconds following engine start and from a fuel temperature of 20 °C.

Rail pressure regulation via the quantity control valve improves the efficiency of the high-pressure pump and lowers the fuel temperature in the fuel return.