The pressure regulating valve has the task of regulating and maintaining the pressure in the high-pressure rail, regardless of the engine's load state.
The pressure regulating valve opens so that some of the fuel from the high-pressure rail can go back to the fuel tank via a collector line.
If the pressure in the high-pressure rail is too low, the pressure regulating valve closes and seals off the high-pressure side from the low-pressure side.
The pressure regulating valve has two control circuits:
- one slower, electric control circuit for adjusting a variable mean pressure value in the high-pressure rail
- one faster, mechanical-hydraulic control circuit which equalises high-frequency pressure fluctuations.
The armature of the electric magnet in the pressure regulating valve forces a ball into the sealing seat inside the pressure regulating valve in order to seal off the high-pressure side from the low-pressure side.
For this purpose, a spring presses against the armature.
An electric magnet exerts a force on the armature in order to open the valve ball counter to the spring force.
The entire armature is washed over with fuel to lubricate it and dissipate heat.
| 1 | High pressure pump | 5 | Attachment flange |
|---|---|---|---|
| 2 | Pressure regulating valve | 6 | Overflow cylinder |
| 3 | Attachment flange | 7 | Seal ring – separates high-pressure range and low-pressure range |
| 4 | Electric connection |