Illustration L0008269 shows the high-pressure rail and injectors
| 1 | Injector | 5 | High-pressure line from high-pressure pump to the high-pressure rail |
|---|---|---|---|
| 2 | Rail pressure sensor | 6 | Pressure regulating valve |
| 3 | Line connection from high-pressure rail to injector | 7 | High pressure pump |
| 4 | High-pressure rail | 8 | High-pressure rail seal |
The high-pressure rail (4) has the task of accumulating the fuel under high pressure.
This pressure is monitored by the control unit using the rail pressure sensor (2) and regulated at the high-pressure pump using the pressure regulating valve (6).
The high-pressure pump (7) delivers fuel to the high-pressure rail via the feed line (5) and builds up a pressure of 1350 bar in the high-pressure range.
At the same time, pressure fluctuations which are caused by the pump delivery and the injection are damped by the rail volume.
The pressure in the high-pressure rail (4), which is common to all cylinders, is kept at an almost constant value even when large quantities of fuel are discharged.
This ensures that the injection pressure remains constant when an injector (1) is opened.
The available volume of the high-pressure rail is always filled with pressurised fuel.
The fuel compressibility achieved due to the high pressure is utilised to retain the accumulation effect.
If fuel is then taken from the high-pressure rail for an injection, the pressure in the high-pressure rail remains almost constant.
Likewise, pressure fluctuations from the pulsating supply by the high-pressure pump are equalised.