Equivalence ratio Calculator

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✖Actual Air Fuel Ratio is defined as the ratio of mass of fuel to mass of air in fuel and air mixture in actual working conditions of IC engines.ⓘ Actual Air Fuel Ratio [AFR_actual]			+10% -10%
✖Stoichiometric Air Fuel Ratio is defined as the theoretical air fuel ratio mixture of a IC engine.ⓘ Stoichiometric Air Fuel Ratio [AFR_stoich]			+10% -10%

✖Equivalence ratio is defined as the ratio of the fuel mass flow rate to the air mass flow rate divided by the same ratio at the stoichiometry of the reaction considered.ⓘ Equivalence ratio [Φ]

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Formula

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Equivalence ratio

Formula

`"Φ" = "AFR"_{"actual"}/"AFR"_{"stoich"}`

Example

`"1.22449"="18"/"14.7"`

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Equivalence ratio Solution

STEP 0: Pre-Calculation Summary

Formula Used

Equivalence ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio
Φ = AFR_actual/AFR_stoich
This formula uses 3 Variables

Variables Used

Equivalence ratio - Equivalence ratio is defined as the ratio of the fuel mass flow rate to the air mass flow rate divided by the same ratio at the stoichiometry of the reaction considered.
Actual Air Fuel Ratio - Actual Air Fuel Ratio is defined as the ratio of mass of fuel to mass of air in fuel and air mixture in actual working conditions of IC engines.
Stoichiometric Air Fuel Ratio - Stoichiometric Air Fuel Ratio is defined as the theoretical air fuel ratio mixture of a IC engine.

STEP 1: Convert Input(s) to Base Unit

Actual Air Fuel Ratio: 18 --> No Conversion Required
Stoichiometric Air Fuel Ratio: 14.7 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

Φ = AFR_actual/AFR_stoich --> 18/14.7

Evaluating ... ...

Φ = 1.22448979591837

STEP 3: Convert Result to Output's Unit

1.22448979591837 --> No Conversion Required

FINAL ANSWER

1.22448979591837 ≈ 1.22449 <-- Equivalence ratio

(Calculation completed in 00.004 seconds)

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Home » Physics » IC Engine » Fundamentals of IC Engine » Equivalence ratio

Credits

Created by Akshat Nama

Indian Institute of Information Technology, Design And Manufacturing (IIITDM ), Jabalpur

Akshat Nama has created this Calculator and 4 more calculators!

Verified by Kartikay Pandit

National Institute Of Technology (NIT), Hamirpur

Kartikay Pandit has verified this Calculator and 400+ more calculators!

< 22 Fundamentals of IC Engine Calculators

Overall heat transfer coefficient of IC engine

Go Overall Heat Transfer Coefficient = 1/((1/Heat Transfer Coefficient on Gas Side)+(Thickness of Engine Wall/Thermal conductivity of material)+(1/Heat Transfer Coefficient on Coolant Side))

Fuel Jet Velocity

Go Fuel jet velocity = Coefficient of Discharge*sqrt(((2*(Fuel injection pressure-Pressure of charge inside the cylinder))/Fuel Density))

Rate of convection heat transfer between engine wall and coolant

Go Rate of Convection Heat Transfer = Convection Heat Transfer Coefficient*Surface Area of Engine Wall*(Engine Wall Surface Temperature-Temperature of Coolant)

Mass of air taken in each cylinder

Go Mass of air taken in each cylinder = (Intake air pressure*(Clearance volume+Displaced volume))/([R]*Intake air temperature)

Heat transfer across engine wall given overall heat transfer coefficient

Go Heat Transfer across Engine Wall = Overall Heat Transfer Coefficient*Surface Area of Engine Wall*(Gas side temperature-Coolant Side Temperature)

Power produced by IC engine given work done by engine

Go Power produced by IC engine = Work done per operating cycle*(Engine speed in rps/Crankshaft revolutions per power stroke)

Engine displacement given number of cylinders

Go Engine Displacement = Engine bore*Engine bore*Stroke Length*0.7854*Number of Cylinders

Rate of cooling of engine

Go Rate of Cooling = Rate of Cooling Constant*(Engine Temperature-Engine surrounding Temperature)

Time taken for engine to cool

Go Time taken to cool Engine = (Engine Temperature-Final Engine Temperature)/Rate of Cooling

Engine rpm

Go Engine RPM = (Speed of vehicle in mph*Gear Ratio of Transmission*336)/Tire Diameter

Kinetic energy stored in flywheel of IC engine

Go Kinetic energy stored in the flywheel = (Flywheel moment of inertia*(Flywheel angular velocity^2))/2

Swept Volume

Go Swept volume = (((pi/4)*Inner Diameter of Cylinder^2)*Stroke Length)

Work done per operating cycle in IC engine

Go Work done per operating cycle = Mean effective pressure in pascals*Displacement volume of piston

Brake output per displacement of piston

Go Brake output per displacement = Brake power per cylinder per stroke/Displaced volume

Engine specific volume

Go Engine specific volume = Displaced volume/Brake power per cylinder per stroke

Brake specific power

Go Brake specific power = Brake power per cylinder per stroke/Area of Piston

Equivalence ratio

Go Equivalence ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio

Brake work per cylinder per stroke

Go Brake work per cylinder per stroke = Bmep*Displaced volume

Compression Ratio given Clearance and Swept Volume

Go Compression Ratio = 1+(Swept volume/Clearance volume)

Engine Capacity

Go Engine capacity = Swept volume*Number of Cylinders

Mean piston speed

Go Mean Piston Speed = 2*Stroke Length*Engine Speed

Peak torque of engine

Go Peak Torque of Engine = Engine Displacement*1.25

Equivalence ratio Formula

Equivalence ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio
Φ = AFR_actual/AFR_stoich

Air-fuel ratio

A mixture that contains just enough air for complete combustion of all the fuel in the mixture is called a chemically correct or stoi-chiometric fuel-air ratio. A mixture having more fuel than that in a chemically correct mixture is termed as rich mixture and a mixture that contains less fuel (or excess air) is called a lean mixture. The ratio of actual fuel-air ratio to stoichiometric fuel-air ratio is called equivalence ratio and is denoted by o.

How to Calculate Equivalence ratio?

Equivalence ratio calculator uses Equivalence ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio to calculate the Equivalence ratio, The equivalence ratio Φ is defined as the ratio of the fuel mass flow rate to the air mass flow rate divided by the same ratio at the stoichiometry of the reaction considered. Equivalence ratio is denoted by Φ symbol.

How to calculate Equivalence ratio using this online calculator? To use this online calculator for Equivalence ratio, enter Actual Air Fuel Ratio (AFR_actual) & Stoichiometric Air Fuel Ratio (AFR_stoich) and hit the calculate button. Here is how the Equivalence ratio calculation can be explained with given input values -> 1.22449 = 18/14.7.

FAQ

What is Equivalence ratio?

The equivalence ratio Φ is defined as the ratio of the fuel mass flow rate to the air mass flow rate divided by the same ratio at the stoichiometry of the reaction considered and is represented as Φ = AFR_actual/AFR_stoich or Equivalence ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio. Actual Air Fuel Ratio is defined as the ratio of mass of fuel to mass of air in fuel and air mixture in actual working conditions of IC engines & Stoichiometric Air Fuel Ratio is defined as the theoretical air fuel ratio mixture of a IC engine.

How to calculate Equivalence ratio?

The equivalence ratio Φ is defined as the ratio of the fuel mass flow rate to the air mass flow rate divided by the same ratio at the stoichiometry of the reaction considered is calculated using Equivalence ratio = Actual Air Fuel Ratio/Stoichiometric Air Fuel Ratio. To calculate Equivalence ratio, you need Actual Air Fuel Ratio (AFR_actual) & Stoichiometric Air Fuel Ratio (AFR_stoich). 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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