Indicated Thermal Efficiency Calculator
Indicated Thermal Efficiency Calculator: Combustion Performance Before Mechanical Losses
Indicated thermal efficiency isolates how well an engine's combustion process converts fuel energy into work on the piston, before subtracting friction, pumping, and accessory losses that bring it down to brake efficiency. It's a useful diagnostic for combustion system performance specifically.
The Formula
Efficiency% = Indicated Power / (Fuel Flow × Heating Value) × 100
Worked Example
An engine develops 100 kW of indicated power while burning fuel at 0.006 kg/s with a heating value of 44,000 kJ/kg.
Fuel Power = 0.006 × 44,000 = 264 kW, Efficiency = 100/264 × 100 = 37.88%
How to Use This Calculator
- Enter the indicated power in kW.
- Enter the fuel flow rate in kg/s.
- Enter the fuel heating value in kJ/kg.
- Click Calculate to get the indicated thermal efficiency percentage.
Related Calculations
Compare against the BSFC Calculator, which measures overall brake efficiency including mechanical losses.