1. What is a Brake-Specific Fuel Consumption Calculator?

Definition: This calculator determines the brake-specific fuel consumption (BSFC) of an engine, which measures fuel efficiency as the fuel consumed per unit of power output. It also calculates the engine efficiency based on the fuel type.

Purpose: It is used in automotive and mechanical engineering to evaluate engine efficiency and fuel consumption.

2. How Does the Calculator Work?

The calculator uses the following formulas:

$$\text{BSFC}=\frac{r}{P}$$ $$e=\frac{1}{d_{\text{energy}}\times \text{BSFC}}\times 100\mathrm{\%}$$ Where:

• $\text{BSFC}$: Brake-specific fuel consumption (g/kWh, kg/hp·h, lb/hp·h)
• $r$: Fuel consumption (g/s, g/min, g/hr, kg/s, kg/min, kg/hr, lb/s, lb/min, lb/hr)
• $P$: Power (W, kW, MW, hp)
• $e$: Engine efficiency (%)
• $d_{\text{energy}}$: Energy density of the fuel (kWh/g)

Unit Conversions:

• Fuel Consumption (r): g/s, g/min (1 g/min = 1/60 g/s), g/hr (1 g/hr = 1/3600 g/s), kg/s (1 kg/s = 1000 g/s), kg/min (1 kg/min = 1000/60 g/s), kg/hr (1 kg/hr = 1000/3600 g/s), lb/s (1 lb/s = 453.592 g/s), lb/min (1 lb/min = 453.592/60 g/s), lb/hr (1 lb/hr = 453.592/3600 g/s)
• Power (P): W, kW (1 kW = 1000 W), MW (1 MW = 1000000 W), hp (1 hp = 745.7 W)
• BSFC: g/kWh, kg/hp·h (1 g/kWh = (1/1000)/0.7457 kg/hp·h), lb/hp·h (1 kg/hp·h = 2.20462 lb/hp·h)
• Energy Density (d_energy): Methane (0.0139 kWh/g), LPG (0.01264 kWh/g), Gasoline (0.01206 kWh/g), Diesel (0.01183 kWh/g), Kerosene (0.01194 kWh/g)

Steps:

• Enter the fuel consumption (r), selecting the unit.
• Enter the power (P), selecting the unit.
• Select the fuel type.
• Convert inputs to base units (g/s for fuel consumption, kW for power).
• Calculate BSFC using the formula and convert to the selected unit.
• Calculate efficiency using the energy density of the selected fuel.
• Display the results.

3. Importance of BSFC Calculation

Calculating BSFC and efficiency is crucial for:

• Engine Design: Optimizing fuel efficiency in engines.
• Performance Analysis: Comparing the efficiency of different engines or fuels.
• Environmental Impact: Reducing fuel consumption and emissions.

4. Using the Calculator

Examples:

• Example 1: For $r=50\text{g/s}$, $P=100\text{kW}$, Fuel: Gasoline:
  • BSFC: $\text{BSFC}=\frac{50}{100}\times 3600=1800\text{g/kWh}$
  • In kg/hp·h: $\text{BSFC}=\frac{1800}{1000}÷0.7457=2.414\text{kg/hp·h}$
  • In lb/hp·h: $\text{BSFC}=2.414\times 2.20462=5.322\text{lb/hp·h}$
  • Efficiency: $e=\frac{1}{0.01206\times 1800}\times 100=4.61\mathrm{\%}$
• Example 2: For $r=1\text{kg/min}$, $P=500\text{hp}$, Fuel: Diesel:
  • Convert: $r=\frac{1\times 1000}{60}=16.667\text{g/s}$, $P=500\times 0.7457=372.85\text{kW}$
  • BSFC: $\text{BSFC}=\frac{16.667}{372.85}\times 3600=160.92\text{g/kWh}$
  • In kg/hp·h: $\text{BSFC}=\frac{160.92}{1000}÷0.7457=0.216\text{kg/hp·h}$
  • Efficiency: $e=\frac{1}{0.01183\times 160.92}\times 100=52.55\mathrm{\%}$

5. Frequently Asked Questions (FAQ)

Q: What is BSFC?
A: Brake-specific fuel consumption (BSFC) measures the fuel efficiency of an engine, calculated as $\text{BSFC}=\frac{r}{P}$.

Q: Can BSFC be negative?
A: No, BSFC cannot be negative as both fuel consumption and power are positive quantities.

Q: How does fuel type affect efficiency?
A: The fuel type affects efficiency through its energy density. Fuels with higher energy density (e.g., Diesel) generally result in higher efficiency for the same BSFC.

Brake-Specific Fuel Consumption Calculator© - All Rights Reserved 2025