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Relative Air-Fuel Ratio Calculator

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Air Standard Cycles Design of IC Engine Components Engine Performance Parameters Fuel Injection in IC Engine

✖Actual air fuel ratio is the actual mass of air mixed with actual mass of fuel that is present during combustion inside IC engine. It is a crucial parameter for good fuel economy in IC engines.ⓘ Actual Air Fuel Ratio [R_a]			+10% -10%
✖Stoichiometric air fuel ratio refers to a mixture that contains just enough air for complete combustion of all the fuel in the mixture. Achieving a stoichiometric ratio minimizes harmful emissions.ⓘ Stoichiometric Air Fuel Ratio [R_i]			+10% -10%

✖Relative Air Fuel Ratio indicates whether the mixture is rich (< 1) or lean (> 1) compared to the ideal stoichiometric ratio. It is the ratio of air and fuel in a mixture that is ready for combustion.ⓘ Relative Air-Fuel Ratio [Φ]

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Relative Air-Fuel Ratio Solution

STEP 0: Pre-Calculation Summary

Formula Used

Relative Air Fuel Ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio
Φ = R_a/R_i
This formula uses 3 Variables

Variables Used

Relative Air Fuel Ratio - Relative Air Fuel Ratio indicates whether the mixture is rich (< 1) or lean (> 1) compared to the ideal stoichiometric ratio. It is the ratio of air and fuel in a mixture that is ready for combustion.
Actual Air Fuel Ratio - Actual air fuel ratio is the actual mass of air mixed with actual mass of fuel that is present during combustion inside IC engine. It is a crucial parameter for good fuel economy in IC engines.
Stoichiometric Air Fuel Ratio - Stoichiometric air fuel ratio refers to a mixture that contains just enough air for complete combustion of all the fuel in the mixture. Achieving a stoichiometric ratio minimizes harmful emissions.

STEP 1: Convert Input(s) to Base Unit

Actual Air Fuel Ratio: 15.9936 --> No Conversion Required
Stoichiometric Air Fuel Ratio: 14.7 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

Φ = R_a/R_i --> 15.9936/14.7

Evaluating ... ...

Φ = 1.088

STEP 3: Convert Result to Output's Unit

1.088 --> No Conversion Required

FINAL ANSWER

1.088 <-- Relative Air Fuel Ratio

(Calculation completed in 00.004 seconds)

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Credits

Created by Syed Adnan

Ramaiah University of Applied Sciences (RUAS), bangalore

Syed Adnan has created this Calculator and 200+ more calculators!

Verified by Kartikay Pandit

National Institute Of Technology (NIT), Hamirpur

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Mean Effective Pressure in Diesel Cycle

LaTeX Go Mean Effective Pressure of Diesel Cycle = Pressure at Start of Isentropic Compression*(Heat Capacity Ratio*Compression Ratio^Heat Capacity Ratio*(Cut-off Ratio-1)-Compression Ratio*(Cut-off Ratio^Heat Capacity Ratio-1))/((Heat Capacity Ratio-1)*(Compression Ratio-1))

Mean Effective Pressure in Otto Cycle

LaTeX Go Mean Effective Pressure of Otto Cycle = Pressure at Start of Isentropic Compression*Compression Ratio*(((Compression Ratio^(Heat Capacity Ratio-1)-1)*(Pressure Ratio-1))/((Compression Ratio-1)*(Heat Capacity Ratio-1)))

Work Output for Otto Cycle

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Relative Air-Fuel Ratio Formula

LaTeX Go

Relative Air Fuel Ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio
Φ = R_a/R_i

What is Stoichiometric A/F Ratio?

The Stoichiometric Air-Fuel Ratio (A/F Ratio) refers to the ideal ratio of air to fuel required for complete combustion. It's essentially the perfect balance where all the fuel is burned by all the available oxygen in the air.
Here are some key points to note:
1.Complete Combustion: At the stoichiometric A/F ratio, all the fuel molecules react with oxygen molecules to form products like water vapor and carbon dioxide. This complete combustion maximizes the energy obtainable from the fuel.
2.Specific Ratio for Each Fuel: The stoichiometric A/F ratio depends on the specific type of fuel being used. For gasoline engines, this ratio is typically around 14.7:1 (14.7 parts air to 1 part fuel by mass). Other fuels like diesel or natural gas will have different stoichiometric ratios.
3.Theoretical Ideal: It's important to remember that the stoichiometric A/F ratio is a theoretical ideal. In real-world engines, achieving this perfect ratio all the time might not be practical or desirable.

How to Calculate Relative Air-Fuel Ratio?

Relative Air-Fuel Ratio calculator uses Relative Air Fuel Ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio to calculate the Relative Air Fuel Ratio, Relative Air-Fuel Ratio is a concept used to describe the actual air-fuel mixture present in an engine compared to the ideal or chemically correct mixture(Stoichiometric A/F ratio). It compares the actual air-fuel mixture in the engine to the stoichiometric ratio. A Relative AFR of 1 indicates a stoichiometric mixture. Values less than 1 represent rich mixtures, and values greater than 1 indicate lean mixtures. Understanding Relative A/F ratio is crucial for engine performance and emissions. Relative Air Fuel Ratio is denoted by Φ symbol.

How to calculate Relative Air-Fuel Ratio using this online calculator? To use this online calculator for Relative Air-Fuel Ratio, enter Actual Air Fuel Ratio (R_a) & Stoichiometric Air Fuel Ratio (R_i) and hit the calculate button. Here is how the Relative Air-Fuel Ratio calculation can be explained with given input values -> 1.088 = 15.9936/14.7.

FAQ

What is Relative Air-Fuel Ratio?

Relative Air-Fuel Ratio is a concept used to describe the actual air-fuel mixture present in an engine compared to the ideal or chemically correct mixture(Stoichiometric A/F ratio). It compares the actual air-fuel mixture in the engine to the stoichiometric ratio. A Relative AFR of 1 indicates a stoichiometric mixture. Values less than 1 represent rich mixtures, and values greater than 1 indicate lean mixtures. Understanding Relative A/F ratio is crucial for engine performance and emissions and is represented as Φ = R_a/R_i or Relative Air Fuel Ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio. Actual air fuel ratio is the actual mass of air mixed with actual mass of fuel that is present during combustion inside IC engine. It is a crucial parameter for good fuel economy in IC engines & Stoichiometric air fuel ratio refers to a mixture that contains just enough air for complete combustion of all the fuel in the mixture. Achieving a stoichiometric ratio minimizes harmful emissions.

How to calculate Relative Air-Fuel Ratio?

Relative Air-Fuel Ratio is a concept used to describe the actual air-fuel mixture present in an engine compared to the ideal or chemically correct mixture(Stoichiometric A/F ratio). It compares the actual air-fuel mixture in the engine to the stoichiometric ratio. A Relative AFR of 1 indicates a stoichiometric mixture. Values less than 1 represent rich mixtures, and values greater than 1 indicate lean mixtures. Understanding Relative A/F ratio is crucial for engine performance and emissions is calculated using Relative Air Fuel Ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio. To calculate Relative Air-Fuel Ratio, you need Actual Air Fuel Ratio (R_a) & Stoichiometric Air Fuel Ratio (R_i). With our tool, you need to enter the respective value for Actual Air Fuel Ratio & Stoichiometric Air Fuel Ratio and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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