Engine - Pcomp vs Pmax Ratio
Ratio of peak firing pressure (Pmax) to compression pressure (Pcomp) - the simplest indicator of injection timing quality on a slow-speed 2-stroke.
Pmax / Pcomp
1.250 -
Pmax − Pcomp
35.0bar
Diagnosis
Normal (1.15–1.35)
Formula, assumptions, and limits
Slow-speed MAN/WinGD design target 1.20–1.35 at MCR. r < 1.15 usually means fuel-injection-angle (FIA) late; r > 1.4 indicates early injection or stuck needle.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| Compression pressure (no fuel) | bar | electronic indicator | |
| Peak firing pressure | bar | PiMax sensor |