What is an Air-Fuel Ratio (AFR) Calculator

Air-Fuel Ratio (AFR) Calculator computes the stoichiometric ratio of air to fuel required for complete combustion, as well as the mass of air needed for a given fuel mass.

It is widely used in combustion processes, including internal combustion engines, gas turbines, and heating devices, to optimize efficiency and reduce emissions.

How to Calculate AFR

Select a fuel type or choose 'Custom' and input a custom AFR value, then provide the mass of fuel. The calculator uses the following formulas:

• Stoichiometric Air-Fuel Ratio (AFR): For predefined fuels, the AFR is a lookup value (e.g., Methane = 17.19:1). For custom fuels, it is the user-provided value \( AFR_{\text{custom}} \).
• Mass of Air Required: \[ \text{Mass of Air} = \text{Mass of Fuel} \times AFR \] where \( \text{Mass of Fuel} \) is in kg, and \( AFR \) is the air-fuel ratio (mass basis).

Click 'Calculate' to see the results.

Examples

Example 1 (Methane): Fuel = Methane, Mass of Fuel = 1 kg.

Calculation: AFR = 17.19:1, Mass of Air = 1 × 17.19 = 17.19 kg

Example 2 (Custom): Custom AFR = 9.0, Mass of Fuel = 1 kg.

Calculation: AFR = 9.0:1, Mass of Air = 1 × 9.0 = 9.0 kg

Example 3 (Propane): Fuel = Propane, Mass of Fuel = 2 kg.

Calculation: AFR = 15.64:1, Mass of Air = 2 × 15.64 = 31.28 kg

Enter values and click 'Calculate' to verify.

Frequently Asked Questions (FAQs)

1. What is the air-fuel ratio?

AFR is the mass ratio of air to fuel required for complete combustion, with stoichiometric AFR being the ideal ratio.

2. How is mass of air calculated?

It’s calculated as the mass of fuel multiplied by the AFR.

3. What is a custom AFR?

For custom fuels, you input the AFR value manually to calculate the mass of air required.

4. Why use stoichiometric AFR?

It ensures complete combustion, optimizing energy release and minimizing pollutants.