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AFR (Air-to-Fuel Ratio) Calculator

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How do you calculate the air-to-fuel ratio for your engine? The AFR (Air-to-Fuel Ratio) Calculator can help you determine this important value with ease. Enter mass of air and fuel into calculator to find out AFR.

What Is AFR (Air-to-Fuel Ratio)?

AFR stands for Air-to-Fuel Ratio. It is the ratio of the mass of air to the mass of fuel in an internal combustion engine. This ratio is important for the performance of  engine, fuel efficiency, and emissions control.

AFR (Air-to-Fuel Ratio) Calculator

Mass of Air (g): Enter the mass of air in grams.

Mass of Fuel (g): Enter the mass of fuel in grams.

AFR: 1 – The calculated Air-to-Fuel Ratio.

Air-to-Fuel Ratio Calculator

User Guide

To use the AFR calculator is simple . Here’s how you can do it:

  1. Enter Mass of Air (g): Input the mass of air in grams.
  2. Enter Mass of Fuel (g): Input the mass of fuel in grams.
  3. Enter AFR : 1: Input the AFR value.

Example Values

For example:

  • Mass of Air: 14400 g
  • Mass of Fuel: 1000 g
  • AFR: 14.4 : 1

Formula

The formula to calculate AFR is:

Variable Description
Mass of Air Mass of air in grams
Mass of Fuel Mass of fuel in grams
AFR Air-to-Fuel Ratio

How To calculate – Examples

Example 1

  • Mass of Air: 14400 g
  • Mass of Fuel: 1000 g

 Calculation:

AFR: 144001000=14.4

Result: The AFR is 14.4 : 1.

Example 2

  • Mass of Air: 12000 g
  • Mass of Fuel: 800 g

Calculation:

AFR:

12000800=15

 

Result: The AFR is 15 : 1.

Air to Fuel Ratio (AFR) Chart

Fuel Type Stoichiometric AFR Rich Mixture AFR (more fuel) Lean Mixture AFR (more air)
Gasoline 14.7:1 10:1 16:1
Diesel 14.5:1 12:1 18:1
Ethanol (E100) 9:1 6:1 10:1
Methanol 6.4:1 4:1 7:1
Propane 15.67:1 11:1 17:1
Natural Gas (Methane) 17.2:1 12:1 19:1
Hydrogen 34:1 29:1 37:1
E85 (85% Ethanol, 15% Gas) 9.8:1 7:1 11:1

I hope you liked our AFR Calculator . How was your experience using the tool? If you are facing any errors, please report them on our “Report an Error” page.

 

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