Subjects:
- Fuel Gallery
- Rail pressure sensor
- Fuel gallery with a diesel engine
- Fuel gallery at a petrol engine
Fuel Gallery:
A fuel gallery is mounted on high-pressure injection engines, such as common rail diesel engines and more and more petrol engines today. The high-pressure pump supplies a pressure that remains on the fuel gallery. All injectors or injectors are linked to this. Each injector or atomizer injects at a different time. As a result, there is always a regular pressure "loss", which is readjusted by the high-pressure pump. Further down this page, the differences and the pressures of the galleries for petrol and diesel engines are described in more detail.
The fuel gallery not only supplies the injectors and injectors with fuel, but also dampens the pressure fluctuations caused by the pump. The injectors and injectors do not suffer from this. A fuel gallery always has a supply line (from the pump), a return line (which goes back to the tank), a pressure sensor and a pressure control valve.
Rail pressure sensor:
The rail pressure sensor is a MAP sensor (a piezoresistive semiconductor sensor). This sensor transmits the pressure prevailing in the fuel gallery to the ECU. In the event of a pressure difference, a different voltage will be passed on, which the control unit then recognizes.
If the pressure becomes too high, the pressure control valve will reduce the pressure. More fuel then goes to the return section (and is returned to the tank). If the pressure is too low, the fuel pump will increase the pressure on the fuel gallery.
Fuel gallery for a diesel engine:
Below is a V8 common rail diesel engine from a BMW. Here you can clearly see how the pipe goes from the high-pressure pump to the valve block and then branches to the two fuel galleries. Each cylinder bank has its own gallery. A valve block has been chosen for this engine, so that the pressure control valve and the rail pressure sensor are centrally mounted and therefore do not have to be performed twice.
Metal pipes with large swivels lead from the fuel gallery to the injectors. This is necessary, because the pressure in the gallery can rise to 1300 bar.
Fuel gallery for a petrol engine:
The image shows two fuel galleries of a V8 petrol engine. These fuel galleries are very different from those of the diesel engine. The injectors in the petrol version are simply mounted on the fuel gallery with clips, in contrast to the diesel engine, where the injectors are mounted on the gallery with separate pipes and large swivels. With the petrol engine, the pressure rises to between 3 and 8 bar, whereby the clips (with which the injectors are attached to the rail) are sufficiently resistant to these pressures.
