Common-rail diesel injectors are precision solenoid or piezoelectric actuators that deliver fuel at pressures up to 2500+ bar. The ECU controls injection timing, duration, and multiple injection events per combustion cycle.
Обзор
Modern injectors can perform 5+ injection events per cycle: pilot(s), main, and post injection(s). Precise control of each event affects power, emissions, noise, and fuel economy.
Injector Types
- Solenoid — electromagnetic actuation, common and reliable
- Piezoelectric — faster response, more precise, higher cost
ECU Control
- Injection quantity (µs pulse width)
- Injection timing (degrees BTDC/ATDC)
- Number of injection events
- Rail pressure coordination
- IMA (Injector Mean Adaptation) values
Calibration Considerations
- Injector coding/IMA must match actual injectors
- Flow rate limits maximum power
- Larger injectors require recalibration
Диагностика
- Injector circuit faults
- IQ deviation by cylinder
- Zero quantity calibration errors
- Return flow excessive
Best Practices
- Use quality fuel to maximize injector life
- Code injectors properly when replacing
- Monitor cylinder balance and IMA values
