Equations · equation
Diesel Cycle Efficiency
Thermodynamics · 1893
- Equation
- η = 1 − (1/r^(γ−1)) · (α^γ − 1)/(γ(α − 1))
- Field
- Thermodynamics
- Named After
- Rudolf Diesel
- Symbols
- r compression ratio · α cut-off ratio, the volume expansion during fuel injection · γ ratio of specific heats
- Year
- 1893
Significance
Heat is added at constant pressure while fuel sprays in, not at constant volume; for the same compression ratio that costs efficiency, but compression ignition allows r of 15–22 where petrol knocks at 10, so the diesel wins in the end — which is why lorries, ships and generators use it.
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