The common rail system uses a type of accumulation chamber called a rail to store pressurized fuel, and injectors that contain electronically controlled solenoid valves to inject the pressurized fuel into the cylinders.
Because the engine ECU controls the injection system (including the injection pressure, injection rate, and injection timing), the injection system is independent and thus unaffected by the engine speed or load.
Because the engine ECU can control injection quantity and timing to a high level of precision, even multi-injection (multiple fuel injections in one injection stroke) is possible.
This ensures a stable injection pressure at all times, even in the low engine speed range, and dramatically decreases the amount of black smoke ordinarily emitted by a diesel engine during start-up and acceleration. As a result, exhaust gas emissions are cleaner and reduced, and higher power output is achieved.
Features of Injection Control
Injection Pressure Control
• Enables high-pressure injection even at low engine speeds.
• Optimizes control to minimize particulate matter and NOx emissions.
Injection Timing Control
• Enables finely tuned optimized control in accordance with driving conditions.
Injection Rate Control
• Pilot injection control injects a small amount of fuel before the main injection.