Common rail systems feature a modular structure. The high-pressure pump, injectors, rail and electronic control unit all belong to one system. Bosch offers common rail systems for various medium and heavy-duty applications in on-and-off-highway use. They attain peak injection pressures of up to 2,500 bar – even in the part load range. This guarantees low fuel consumption with correspondingly reduced CO₂ emissions and enables exhaust gas recirculation to reduce nitrogen oxides (NOx). In doing so, Bosch common rail systems make an important contribution to meeting the strictest emissions targets for commercial vehicles, such as Euro 6 or US10.
In conventional diesel injection systems, the fuel pressure must be generated separately for each injection. In the common rail system, however, pressure generation and injection are separate, so that the fuel is permanently available at the pressure necessary for injection. Pressure generation takes place in the high-pressure pump. This compresses the fuel and carries it via a high-pressure pipe into the rail intake, which serves as a common high-pressure storage tank for all injectors – hence the name "common rail" . From here, the fuel is distributed to the individual injectors, which inject it into the combustion chamber of the cylinder.