Combustion efficiency Calculator

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Engine Performance Parameters

Air-Standard Cycles

Design of IC Engine Components

Fuel Injection in IC Engine

Fundamentals of IC Engine

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For 4 Stroke Engine

For 2 Stroke Engine

✖Heat added by combustion per cycle is defined as the amount of heat energy liberated from the combustion of the fuel in one working cycle.ⓘ Heat added by combustion per cycle [Q_in]			+10% -10%
✖Mass of fuel added per cycle is defined as the fuel that gets combustible in one cycle.ⓘ Mass of fuel added per cycle [m_f]			+10% -10%
✖Heating value of the fuel is defined as the chemical energy per unit mass of the fuel.ⓘ Heating value of the fuel [Q_HV]			+10% -10%

✖Combustion efficiency is defined as the actual heat input to the theoretical heat input in the engine cylinder.ⓘ Combustion efficiency [η_c]

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Formula

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Combustion efficiency

Formula

`"η"_{"c"} = "Q"_{"in"}/("m"_{"f"}*"Q"_{"HV"})`

Example

`"0.6"="150kJ/kg"/("0.005"*"50000kJ/kg")`

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Combustion efficiency Solution

STEP 0: Pre-Calculation Summary

Formula Used

Combustion efficiency = Heat added by combustion per cycle/(Mass of fuel added per cycle*Heating value of the fuel)
η_c = Q_in/(m_f*Q_HV)
This formula uses 4 Variables

Variables Used

Combustion efficiency - Combustion efficiency is defined as the actual heat input to the theoretical heat input in the engine cylinder.
Heat added by combustion per cycle - (Measured in Joule per Kilogram) - Heat added by combustion per cycle is defined as the amount of heat energy liberated from the combustion of the fuel in one working cycle.
Mass of fuel added per cycle - Mass of fuel added per cycle is defined as the fuel that gets combustible in one cycle.
Heating value of the fuel - (Measured in Joule per Kilogram) - Heating value of the fuel is defined as the chemical energy per unit mass of the fuel.

STEP 1: Convert Input(s) to Base Unit

Heat added by combustion per cycle: 150 Kilojoule per Kilogram --> 150000 Joule per Kilogram (Check conversion here)
Mass of fuel added per cycle: 0.005 --> No Conversion Required
Heating value of the fuel: 50000 Kilojoule per Kilogram --> 50000000 Joule per Kilogram (Check conversion here)

STEP 2: Evaluate Formula

Substituting Input Values in Formula

η_c = Q_in/(m_f*Q_HV) --> 150000/(0.005*50000000)

Evaluating ... ...

η_c = 0.6

STEP 3: Convert Result to Output's Unit

0.6 --> No Conversion Required

FINAL ANSWER

0.6 <-- Combustion efficiency

(Calculation completed in 00.004 seconds)

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Home » Physics » IC Engine » Engine Performance Parameters » For 4 Stroke Engine » Combustion efficiency

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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

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

< 24 For 4 Stroke Engine Calculators

Volumetric efficiency of IC engine

Go Volumetric efficiency of IC engine = (Air Mass Flow Rate*Crankshaft revolutions per power stroke)/(Air density at intake*Theoretical volume of engine*Engine speed in rps)

Rate of heat conduction of engine wall

Go Rate of Heat Conduction of Engine Wall = ((-Thermal conductivity of material)*Surface Area of Engine Wall*Temperature Difference across Engine Wall)/Thickness of Engine Wall

Brake power measured with dynamo meter

Go Brake power measured with dynamo meter = (pi*Pulley diameter*(Engine speed in rps*60)*(Dead weight-Spring scale reading))/60

Indicated Power of Four-stroke Engine

Go Indicated Power = (Number of Cylinders*Mean Effective Pressure*Stroke Length*Area of Cross Section*(Engine Speed))/(2)

Volumetric Efficiency for 4S engines

Go Volumetric Efficiency = ((2*Air Mass Flow Rate)/(Air density at intake*Piston Swept Volume*(Engine Speed)))*100

Brake Mean Effective Pressure of 4S Engines given Brake power

Go Brake Mean Effective Pressure = (2*Brake Power)/(Stroke Length*Area of Cross Section*(Engine Speed))

Work done per cycle in ic engine

Go Work done per cycle in ic engine = (Indicated engine power*Crankshaft revolutions per power stroke)/Engine Speed in rpm

Fuel conversion efficiency

Go Fuel conversion efficiency = Work done per cycle in ic engine/(Mass of fuel added per cycle*Heating value of the fuel)

Combustion efficiency

Go Combustion efficiency = Heat added by combustion per cycle/(Mass of fuel added per cycle*Heating value of the fuel)

Intake air mass of engine cylinder

Go Mass of air at intake = (Air Mass Flow Rate*Crankshaft revolutions per power stroke)/Engine Speed in rpm

Bmep given engine torque

Go Bmep = (2*pi*Engine Torque*Engine Speed)/Mean Piston Speed

Displaced volume in engine cylinder

Go Displaced volume = (Piston stroke*pi*(Engine cylinder bore in meter^2))/4

Intake air density

Go Air density at intake = Intake air pressure/([R]*Intake air temperature)

Thermal efficiency of IC engine

Go Thermal efficiency of ic engine = Work done per cycle in ic engine/Heat added by combustion per cycle

Volumetric efficiency of IC engine given actual volume of engine cylinder

Go Volumetric efficiency of IC engine = Actual volume of intake air/Theoretical volume of engine

Connecting rod length to crank radius ratio

Go Connecting rod length to crank radius ratio = Connecting rod length/Crank Radius of Engine

Ratio of cylinder bore to piston stroke

Go Connecting rod length to crank radius ratio = Connecting rod length/Crank Radius of Engine

Total cylinder volume of IC engine

Go Total volume of an engine = Total number of cylinders*Total volume of engine cylinder

Fuel conversion efficiency given thermal conversion efficiency

Go Fuel conversion efficiency = Combustion efficiency*Thermal conversion efficiency

Frictional power of engine

Go Frictional power of engine = Indicated Power of Engine-Brake power of engine

Actual intake air volume per cylinder

Go Actual volume of intake air = Mass of air at intake/Air density at intake

Horsepower of engine

Go Horsepower of engine = (Engine Torque*Engine RPM)/5252

Indicated mean effective pressure given mechanical efficiency

Go Imep = Bmep/Mechanical efficiency of ic engine

Frictional mean effective pressure

Go Fmep = Imep-Bmep

Combustion efficiency Formula

Combustion efficiency = Heat added by combustion per cycle/(Mass of fuel added per cycle*Heating value of the fuel)
η_c = Q_in/(m_f*Q_HV)

What is combustion efficiency?

Combustion efficiency is the rate at which an engine converts fuel into energy. Particularly with heavy fuels with high-energy densities — diesel, fuel oil, bunker fuel, etc. The combustion efficiency increases with increased excess air - until the heat loss in the excess air is larger than the heat provided by more efficient combustion.

How to Calculate Combustion efficiency?

Combustion efficiency calculator uses Combustion efficiency = Heat added by combustion per cycle/(Mass of fuel added per cycle*Heating value of the fuel) to calculate the Combustion efficiency, The Combustion efficiency formula is defined as a measure of how effectively the heat content of a fuel is transferred into usable heat. Combustion efficiency is denoted by η_c symbol.

How to calculate Combustion efficiency using this online calculator? To use this online calculator for Combustion efficiency, enter Heat added by combustion per cycle (Q_in), Mass of fuel added per cycle (m_f) & Heating value of the fuel (Q_HV) and hit the calculate button. Here is how the Combustion efficiency calculation can be explained with given input values -> 0.6 = 150000/(0.005*50000000).

FAQ

What is Combustion efficiency?

The Combustion efficiency formula is defined as a measure of how effectively the heat content of a fuel is transferred into usable heat and is represented as η_c = Q_in/(m_f*Q_HV) or Combustion efficiency = Heat added by combustion per cycle/(Mass of fuel added per cycle*Heating value of the fuel). Heat added by combustion per cycle is defined as the amount of heat energy liberated from the combustion of the fuel in one working cycle, Mass of fuel added per cycle is defined as the fuel that gets combustible in one cycle & Heating value of the fuel is defined as the chemical energy per unit mass of the fuel.

How to calculate Combustion efficiency?

The Combustion efficiency formula is defined as a measure of how effectively the heat content of a fuel is transferred into usable heat is calculated using Combustion efficiency = Heat added by combustion per cycle/(Mass of fuel added per cycle*Heating value of the fuel). To calculate Combustion efficiency, you need Heat added by combustion per cycle (Q_in), Mass of fuel added per cycle (m_f) & Heating value of the fuel (Q_HV). With our tool, you need to enter the respective value for Heat added by combustion per cycle, Mass of fuel added per cycle & Heating value of the fuel 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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