Alcohol Brake Specific Fuel Consumption Calculator

Alcohol Brake Specific Fuel Consumption Guide

Brake Specific Fuel Consumption (BSFC) measures the fuel efficiency of internal combustion engines, indicating the amount of fuel consumed to produce one unit of power over time. It is typically expressed in grams per kilowatt-hour (g/kWh) or pounds per horsepower-hour (lb/hp·h).

Key Factors Affecting BSFC

• Fuel Type – Ethanol (~0.789 kg/l) and methanol (~0.792 kg/l) have different density and energy contents.
• Fuel Volume – The rate of fuel consumption (liters/hour) impacts the total mass used.
• Engine Power – Higher power output (kW) affects BSFC calculations.
• Operating Conditions – Engine tuning and load can influence efficiency.

How the Calculation Works

Fuel Mass (g/hour) = Fuel Volume (liters/hour) × Fuel Density (kg/liter) × 1000

BSFC (g/kWh) = Fuel Mass (g/hour) ÷ Engine Power (kW)

BSFC (lb/hp·h) = [Fuel Mass (kg/hour) × 2.20462] ÷ [Engine Power (kW) × 1.34102]

Typical Fuel Densities

Fuel Type	Density (kg/liter)
Ethanol	0.789
Methanol	0.792
Custom	Varies

Tips for Optimizing BSFC

• Engine Tuning – Optimize air-fuel ratio for alcohol fuels.
• Regular Maintenance – Ensure injectors and ignition systems are in top condition.
• Load Management – Operate at optimal engine load for efficiency.
• Fuel Selection – Choose the alcohol fuel best suited for your engine's design.

Example Calculation

For an engine using 10 liters/hour of ethanol (density 0.789 kg/l) producing 50 kW:

Fuel Mass = 10 × 0.789 × 1000 = 7890 grams/hour

BSFC (g/kWh) = 7890 ÷ 50 = 157.8 g/kWh

BSFC (lb/hp·h) = (7890 × 2.20462 ÷ 1000) ÷ (50 × 1.34102) ≈ 0.2596 lb/hp·h

Final Considerations

A lower BSFC indicates better fuel efficiency. Use this calculator to compare alcohol fuels, optimize engine performance, or evaluate modifications for alcohol-powered engines.