Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Chapter 6

Internal Combustion Engines

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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I. C. Engines

“The heat engine in which the combustion takes place inside the cylinder or the product of combustion (flue gas) directly goes to the cylinder and the heat energy of the flue gas is converted into mechanical energy is known as Internal Combustion Engine (IC Engine).” The combustion may take place either inside or outside the cylinder but heat energy of the combustion is directly utilized by the engine to produce into mechanical power. In external combustion engines, heat of the combustion is transferred to the intermediate medium like water or air and then the heat energy of that intermediate medium (steam produced from the water or the hot air) is converted into the mechanical energy.

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Basis for Classification of I.C. Engines

• Number of strokes per cycle.• Nature of thermodynamic cycle.• Ignition systems.• Fuel used.• Arrangement of cylinders.• Cooling systems.• Fuel supply systems.• Number of strokes per cycle.• Nature of thermodynamic cycle.• Ignition systems.• Fuel used.• Arrangement of cylinders.• Cooling systems.• Fuel supply systems.

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Basic Structure of I.C. Engines

The components of I.C. Engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Stroke Length and Stroke Volume in an IC Engine

Stroke length and stroke volume in I.C. engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Four-stroke Spark Ignition Engine

All the four thermodynamic processes in four strokes SI engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Four Stroke Compression Ignition Engine

All the thermodynamics processes in four strokes of engines

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Two-stroke Spark Ignition Engine

Working of two stroke S.I. engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Two Stroke C.I. Engine

Cut-section of two strokes C.I. engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Working of two strokes C.I. engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Comparison Between Four Strokes and Two Strokes Engines

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Comparison Between S.I. and C.I. Engines

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Otto Cycle

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Diesel Cycle

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Comparison Between Otto Cycle and Diesel Cycle

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Dual Cycle

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Valve Timing Diagram for Four Strokes S.I. Engines

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Port Timing Diagram for Two Strokes S.I. Engines

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Valve Timing Diagram for Four Strokes C.I. Engine

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Engine Performance Parameters

• Indicated Thermal Efficiency

• Brake Thermal Efficiency

• Mechanical Efficiency

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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• Volumetric Efficiency

• Relative Efficiency or Efficiency Ratio

• Mean Effective Pressure

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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• Mean Piston Speed

• Specific Power Output

Basic Mechanical Engineering, First Editionby Dr Pravin Kumar

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Thank You.