Difference Between Internal and External Combustion Engine

Difference Between I.C. Engines and E.C. Engines With Comparison Chart


  • Engine is a device that converts one form of energy into another form.
  • Heat engine is a device that transforms the chemical energy of a fuel into thermal energy and utilizes this thermal energy to perform useful work.
  • Thus, Thermal energy is converted to mechanical energy in a heat engine.
  • A Heat engine may be classified based on where the combustion of fuel takes place, i.e. whether outside the cylinder or inside the cylinder.
    1. External Combustion Engines (E.C. Engines)
    2. Internal Combustion Engines (I.C. Engines)

Comparison of IC engine and EC engine

Comparison Chart

  • Comparison of IC engine and EC engine is given in the table
I.C. Engine E.C. Engine
Combustion of fuel takes place
inside the cylinder
Combustion of fuel takes place
outside the cylinder
Working fluid may be Petrol,
Diesel & Various types of gases
Working fluid is steam
Require less space Require large space
Capital cost is relatively low Capital cost is relatively high
Starting of this engine is easy & quick Starting of this engine requires time
Thermal efficiency is high Thermal Efficiency is low
Power developed per unit
weight of these engines is high
Power Developed per unit
weight of these engines is low
Fuel cost is relatively high Fuel cost is relatively low

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