Relationship between indicated (PMI) and brake (BMEP) mean effective pressure with mechanical efficiency - cross-checks indicator card against brake power test.
Formula
$$ \text{BMEP} = \eta_{mech} \cdot \text{PMI}, \quad \text{FMEP} = \text{PMI} - \text{BMEP} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $PMI$ | Indicated mean effective pressure | bar | indicator card |
| $BMEP$ | Brake mean effective pressure | bar | shaft torque meter |
| $FMEP$ | Friction mean effective pressure | bar | PMI − BMEP |
| $\eta_{mech}$ | Mechanical efficiency | - | brake test |
Sources
- MAN ES Performance Guide.