Modern common-rail diesel engines inject fuel multiple times per combustion cycle to reduce noise, improve emissions, and optimize efficiency.
Injection Sequence
- Pilot injection — small amount 10-30° BTDC, reduces noise
- Main injection — primary fuel for power
- After injection — extends combustion, reduces soot
- Post injection — late injection for DPF regeneration
Calibration Implications
- Reducing pilots increases noise significantly
- Main timing affects power and efficiency
- Post injection requires functional DPF
