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BSFC Calculator

Calculate Brake Specific Fuel Consumption to measure engine efficiency and performance

Calculate BSFC & Engine Efficiency

Unit System

Power Input Method

g/s

Mass flow rate of fuel consumption

kW

Brake power output of the engine

Energy density affects efficiency calculation

BSFC Results

0.0
g/kWh
BSFC (Metric)
0.0%
Efficiency
Thermal Efficiency
0.000
lb/hp⋅h
BSFC (Imperial)

Formula: BSFC = (Fuel Rate ÷ Power) × 3600

Fuel Consumption: 0 g/s

Engine Power: 0.0 kW

Energy Density: 0.01206 kWh/g

Lower BSFC = Better Efficiency

Performance Analysis

Example Calculation

Gasoline Engine Example

Engine Type: 250 kW gasoline engine

Fuel Consumption: 14.78 g/s

Fuel Type: Gasoline (0.01206 kWh/g)

Operating Conditions: Full load

Calculation Steps

1. BSFC = (14.78 g/s ÷ 250 kW) × 3600

2. BSFC = 0.05912 × 3600 = 212.83 g/kWh

3. Efficiency = 1 ÷ (0.01206 × 212.83) × 100%

4. Efficiency = 1 ÷ 2.567 × 100% = 38.96%

Result: 212.8 g/kWh BSFC, 39.0% efficiency

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Typical BSFC Ranges

High-Performance Diesel
180-220 g/kWh
Modern marine/industrial diesels
Automotive Diesel
200-250 g/kWh
Modern passenger car diesels
Gasoline Direct Injection
220-280 g/kWh
Modern GDI engines
Port Fuel Injection
250-320 g/kWh
Traditional gasoline engines
Naturally Aspirated Gasoline
280-350 g/kWh
Older gasoline engines
Two-Stroke Engines
300-450 g/kWh
Small engines, outboards

Understanding BSFC

📊

Lower BSFC = Higher efficiency

Measures fuel consumption per unit power

🔧

Used for engine optimization

🚗

Critical for automotive design

🌱

Environmental impact indicator

💰

Directly affects operating costs

Understanding Brake Specific Fuel Consumption

What is BSFC?

Brake Specific Fuel Consumption (BSFC) is a measure of engine efficiency that calculates how much fuel an engine consumes to produce a unit of power. It's expressed in grams of fuel per kilowatt-hour (g/kWh) or pounds per horsepower-hour (lb/hp⋅h).

Why is BSFC Important?

  • Measures actual engine efficiency under load
  • Enables comparison between different engines
  • Critical for fuel economy calculations
  • Used in engine optimization and tuning

Calculation Formulas

BSFC = (r ÷ P) × 3600

Efficiency = 1 ÷ (d × BSFC) × 100%

P = τ × ω (from torque & RPM)

  • r: Fuel consumption rate (g/s)
  • P: Brake power output (kW)
  • d: Fuel energy density (kWh/g)
  • τ: Torque (Nm)
  • ω: Angular velocity (rad/s)

Note: BSFC values can vary significantly with engine load, speed, and operating conditions. Always consider the test conditions when comparing BSFC values.

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