The "Common-rail" diesel injection system in vehicles has been in use since 1997, and the first passenger cars equipped with the system were the Alfa Romeo 156 1.9 JTD and the Mercedes-Benz 220 CDI (OM 611 engine).
What is a 'Common-rail' diesel fuell injection system?
The system is named after a common high-pressure tank (Common-rail) that supplies all injectors and respectively the engine cylinders with fuel. For conventional diesel injection systems, the fuel pressure must be generated individually for each injection. However, with the Common-rail system, pressure generation and the injection events are separate, meaning that fuel is always available at the required injection pressure.
Common-rail systems are modular. Each system consists of a high-pressure pump, injector, common rail and electronic control unit.
For conventional diesel injection systems, the fuel pressure must be generated individually for each injection. However, with the Common-rail system, pressure generation and injection are separate, meaning that fuel is always available at the required injection pressure. Pressure generation takes place in a high pressure pump. The pump pressurizes the fuel and feeds it through a high pressure pipe into the inlet port of an rail, which acts as a common high pressure tank for all injectors. Hence the name "Common-rail". Fuel is distributed from the common rail to individual injectors, which inject it into the cylinders.
Bosch offers Common-rail systems for all vehicle models, from micro cars to heavy luxury sedans, mobile heavy equipment, and commercial vehicles. High-pressure pumps operate at pressures between 1100 and 2500 bar. Systems with individual pumps (plug pumps) are also available. The injectors use either solenoid valve or Piezo technology.
Benefits of a Common-rail injection system:
• Clean and highly efficient fuel injection due to extremely short injection times and multiple injection capability,
• High engine efficiency and smooth operation with low power consumption and emissions
• Can be used on all vehicle models due to its modular design