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Common Rail System for commercial vehicles

The Common Rail System (CRS) is an accumulator injection system.
The key distinction between this and other injection systems is in the pressurization and injection processes, which are completely independent of each other. The CRS provides the capability for multiple injections and the flexibility to modify each injection for different requirements. With the new systems comes extremely smooth and economical engine performance offering impressive levels of dynamic response.
The CRS consists of:
Low-pressure system with presupply pump and filter
Rail
High-pressure pump
Injectors
ECU with sensors and diagnostic interface
System overview: Injectionsystem with Common Rail and miscellaneous system components 
1 High-pressure pump, 2 Element shutoff valve, 3 Pressure-control valve, 4 Fuel filter, 5 Fuel tank with preliminary filter and presupply pump, 6 ECU, 7 Glowcontrol unit, 8 Battery, 9 High-pressure accumulator (rail), 10 Rail-pressure sensor, 11 Flow limiter,
12 Pressure limiter valve, 13 Fuel-temperature sensor,
14 Fuel injector, 15 Glowplug, 16 Coolant-temperature sensor,
17 Crankshaft-rpm sensor, 18 Camshaft-rpm sensor, 19 Intake-air temperature sensor, 20 Boost-pressure sensor (BPS), 21 Air-mass meter, 22 Exhaust-gas turbocharger, 23 EGR actuator,
24 Boost-pressure actuator, 25 Vacuum pump, 26 Instrument cluster with display for fuel consumption, engine rpm etc.,
27 Accelerator-pedal sensor, 28 Brake contacts, 29 Clutch switch, 30 Vehicle-speed sensor, 31 Control panel for Cruise Control, 32 AC compressor, 33 Control panel for AC, 34 On-board-diagnostics (OBD) display with connection for diagnosis unit 
Product family
Fuel-injection management: Commercial vehicles
Common Rail System: Design and construction 
The high-pressure pump forces the fuel into the high-pressure accumulator (rail). Here, fuel in the accumulator is staged, ready for injection at the appropriate pressure for the particular engine operating conditions.

The driver's requirements are signaled through the accelerator pedal and registered by the ECU together with the operating status. The ECU then uses maps to calculate the required injection pressure and the duration of injection (specifying the fuel mass), and the instant of injection. Each engine cylinder has an injector containing an integral solenoid valve, the opening and closing points of the solenoid defining the beginning and end of the injection process.
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