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What is IC Engines? and Different Types of IC Engines (PDF)

In this article, you learn what is IC Engines its Parts, working principle, Types of Internal Combustion Engines. And difference between steam engine and IC engine.

And also download the PDF file of this article at end of it.

Internal Combustion Engines

As the name implies or suggests, the internal combustion engines (briefly written as I.C. Engine) are those engines in which the combustion of fuel takes place inside the engine cylinder.

In other words, the internal combustion engines are those engines in which the combustion of fuel takes place inside the engine cylinder by a spark. These are petrol, diesel and gas engines.

An engine is a device, which by using the chemical energy of the fuel, transforms it into thermal energy by combustion, to produce mechanical work. We have seen in steam engines that the fuel, fed into the cylinder. It is in the form of steam. Which is already heated and is ready for work in the combustion cycle of the engine.

Difference Between Steam Engines and Internal Combustion Engines.

Following are the difference between steam engine and internal combustion engine:

Types of Engines

  1. External combustion engines (EC)
  2. Internal combustion engines (IC)

External combustion engines – If the combustion of fuel place outside the engine cylinder, it is an external combustion engine. Ex: Steam turbine, Gas Turbine, Steam Turbine etc.

Internal combustion engines – If the combustion fuel takes place inside the engine cylinder, it is an internal combustion engine. Ex: Petrol engine, Diesel Engine.

Types of Internal Combustion Engines

Following is the list of type of IC Engines (Classified according to different method):

  1. Working Cycle Employed
    1. Two-stroke Engine
    2. Four-stroke Engine
  2. Fuel Used
    1. Petrol
    2. Diesel
    3. Gas Engine
  3. Nature of Thermodynamics Cycle Used
    1. Otto Cycle
    2. Diesel Cycle
    3. Dual Cycle
  4. Methods Of Cooling
    1. Air Cooling
    2. Water Cooling
  5. Speed Of The Engine
    1. High-speed Engine
    2. Medium-speed Engine
    3. Low-speed Engine
  6. Field Of Application
    1. Stationary Engine
    2. Automobile Engine
    3. Portable Engine
    4. Aero Engine
  7. Method Of Ignition
    1. Spark-ignition Engine
    2. Compression-Ignition Engine
  8. Arrangement Of The Engine Cylinder
    1. Horizontal Engine
    2. Verticle Engine
    3. Radial Engine
    4. V-type Engine

Parts of Internal Combustion Engines

Following are the main parts of IC engine:

Internal Combustion Engines

1. Cylinder

  • The cylinder is made up of steel or aluminum alloys.
  • In this Piston makes to and for a motion to develop power.
  • It will withstand high pressure and temperature.

2. Cylinder Head

  • Cylinder Head is fitted at the top of the cylinder.
  • It is made up of steel or aluminum alloys.
  • It is made by casting.
  • A copper or asbestos gasket is provided in between the cylinder and the cylinder head to make it airtight.

3. Piston

  • It is made of aluminum alloys.
  • The main function is to transmit force exerted by burning of charge to connecting rod.

4. Piston Rings

  • These are circular rings made up of special steel alloys.
  • these are housed in circumferential grooves of the piston.
  • Two sets of rings are provided, with an upper ring to prevent leakage of burnt gases into the lower portion, while lower ring to prevent leakage of oil into the Engine Cylinder.
  • They retain elastic properties even at a higher temperature.
  • The rings are provided with an airtight seal.

Read also: Piston Rings: Types of Piston Rings

5. Valves

  • These are provided on the cylinder head,
  • Inlet valve is used to take the fresh mixture into the cylinder.
  • The exhaust valve is used to expel burnt gases from the cylinder.

6. Connecting Rod

  • It is a link between the piston and the crankshaft.
  • The function of Connecting Rod is to transmit the force from piston to crankshaft.

7. Crankshaft

  • It is made of special steel alloys.
  • The function of the crankshaft is to convert the reciprocating motion of a piston into rotary motion with the help of connecting rod.

8. Crankcase

  • The crankcase is made of cast iron.
  • It holds the cylinder and crankshaft of an engine.
  • It also serves as a sump (storing place) for lubricating oil.

9. Flywheel

  • It is a big solid wheel mounted on a crankshaft of an IC Engine.
  • The main function of the flywheel is to maintain speed constant.
  • It stores excess energy during power and gives out during the compression stroke.

Working Principle of Internal Combustion Engines

In IC engines (internal combustion engines) the combustion of takes place inside the cylinder, therefore the thermal energy of the fuel is directly converted into mechanical work.

the IC engine has a higher thermal efficiency than the thermal efficiency of EC engines. In internal combustion engines, when the IC engine is working continuously, we may consider a cycle starting from any strokes.

We know that when the engine returns back to the stroke where it starts we say that one cycle has been completed. The IC engine has four steps to complete one cycle as follows:

Suction Stroke In this stroke the fuel vapour, in the correct proportion, is supplied to the engine cylinder.

Compression Stroke In this stroke, the fuel vapour is compressed in the engine cylinder.

Expansion Stroke In this stroke, the fuel vapour burn by the spark plug is provided on the top of the engine cylinder. when the fuel is burned suddenly raise the pressure, due to the expansion of the combustion products in the engine cylinder. The rise of the pressure pushes the piston with a high force and rotates the crankshaft. The crankshaft, in turn, drives the machine connected to it.

Exhaust Stroke In this stroke, the burnt gases are exhausted from the engine cylinder, so as to make space available for the fresh fuel vapour.

Difference Between Petrol Engine and Diesel Engine

The main difference between a petrol engine and a diesel engine is a petrol engine draws a mixture of petrol and air during the suction stroke. And a diesel engine draws only air during the suction stroke.

The petrol engine works on the Otto cycle. It is easy to start, lighter and cheaper, It has a high running cost and low maintenance cost.

The diesel engine works on the diesel cycle. It difficult to start, heavier and costlier, It has low running cost and high maintenance cost.

The petrol engines thermal efficiency is about 26%. These are high-speed engines and used in light-duty vehicles. Where diesel engines thermal efficiency is about 40%. These are low-speed engines and used in heavy-duty vehicles.

Applications of IC Engines

Following are the application of ic engine:

  1. IC engines are used in Road vehicles like scooters, motorcycles, buses etc.
  2. It is also used in Aircraft.
  3. IC engine is commonly used in Motorboats.
  4. IC engine has great application in small machines, such as lawnmowers, chainsaws, and portable engine-generators.

So now, we hope that we have clear all your doubts about Internal Combustion Engine. If you have still any doubts about the “Types of IC Engines” you can ask in the comments.

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Saif M
Saif M. is a Mechanical Engineer by profession. He completed his engineering studies in 2014 and is currently working in a large firm as Mechanical Engineer. He is also an author and editor at theengineerspost.com