AFR Calculator (Air-Fuel Ratio)
Calculate the air-to-fuel ratio (AFR) and lambda equivalence ratio for combustion engines.
Calculation Parameters
Specify your stoichiometry inputs.
Calculated Result
Expert Tip
Ensure units are correctly formatted (e.g. Kelvin for gas temperatures and liters for volumes) to get chemically accurate outputs.
How this Calculator Works
This calculator allows you to solve AFR (Air-Fuel Ratio) problems dynamically. Adjust the input parameters using the sliders or selection menu below:
- Air Mass (kg) (Range: 1 to 100, Default: 14.7)
- Fuel Mass (kg) (Range: 0.1 to 10, Default: 1.0)
The results are computed instantly and updated in the results panel on the right.
Formula & Methodology
Lambda (λ) = AFR / Stoichiometric AFR (14.7 for gasoline)
Where:
- Air Mass: Parameter value.
- Fuel Mass: Parameter value.
Step-by-Step Calculation Example
To calculate AFR (Air-Fuel Ratio) manually, follow these steps:
- Identify the input parameters. For example:
- Air Mass (kg) = 14.7
- Fuel Mass (kg) = 1.0
- Apply the formula:
AFR = Air Mass / Fuel Mass
Lambda (λ) = AFR / Stoichiometric AFR (14.7 for gasoline) - Verify the calculated value which is updated instantly in the results panel on the right.
Frequently Asked Questions
What is the stoichiometric air-fuel ratio for gasoline? ▼
The ideal stoichiometric air-fuel ratio for pure gasoline is 14.7:1 by mass (14.7 kg of air per 1 kg of fuel).
What does a lambda (λ) value greater than 1 mean? ▼
A lambda value > 1.0 indicates a lean mixture (excess air/oxygen), while λ < 1.0 indicates a rich mixture (excess fuel).
How do you calculate mass of air required for complete combustion? ▼
Multiply the stoichiometric AFR constant by the mass of fuel consumed.