Types of Engines and their explanation

Before Discussing the types of engines, first, let us understand what is a heat engine. Any type of machine or engine that derives heat energy from the combustion of fuel or from any other source and which converts this energy into mechanical energy is called a Heat Engine.

Types of Engines

Heat Engines can be classified into the following two types:

• External Combustion Engine
• Internal Combustion Engine

External Combustion Engines (E.C. Engines)

External Combustion engines are those types of engines in which fuel combustion takes place outside the cylinder. For example, if we take the case of a steam engine, the heat of combustion is used to generate the steam used to move the piston in a cylinder. Steam turbines and hot air engines are types of external combustion engines. These engines are generally used to drive locomotives, ships, etc.

Internal Combustion Engines (I.C.Engines)

Internal combustion engines are those types of engines in which the combustion of fuel takes place inside the cylinder. In the cylinder, the combustion of a mixture of fuel and oxygen or air takes place. Nowadays, the Internal Combustion (I.C) engines are mostly used in automobiles.

Classification of IC Engines or Types of Engines

The internal combustion engines are classified as below:

1. According to the Cycle of Operation
   • Two Stroke Engine
   • Four Stroke Engine
2. According to the Cycle of Combustion
   • Otto Cycle Engine
   • Diesel Cycle Engine
   • Dual-Combustion
3. According to Arrangement of Cylinder
   • Single Cylinder Engine
   • In-line Engines
   • V-Engines
   • Opposed Cylinder Engines
   • W-Engine
   • Opposite Piston Engine
   • Radial Engines
4. According to the speed of the Engine
   • Low-speed Engine
   • High-Speed Engine
   • Medium Speed Engine
5. According to Method of Ignition
   • Spark-Ignition Engine
   • Compression-Ignition Engine
6. According to the Method of cooling of Engine
   • Air-cooled Engine
   • Water-cooled Engine
7. According to Valve Arrangement
   • Overhead valve arrangement
   • L-head type Engine
   • T-head type Engine
   • F-head type Engine
8. According to Number of Cylinders
   • Single Cylinder Engine
   • Multi-Cylinder Engine
9. According to the method of Governing
   • Hit and miss governed Engine
   • Quality Governed Engine
   • Quantity Governed Engine
10. According to Fuel Employed
    • Oil Engine
    • Gas Engine
    • Diesel Engine
    • Petrol Engine
    • LPG Engine

Now we will discuss each type one by one:

1.) According to the Cycle of Operation

a.) Two-Stroke Engine

A two-stroke engine is a type of engine that completes the power cycle with two strokes of piston during one revolution of the crankshaft. The two-stroke engine has the following parts:

• Piston
• crankshaft
• connecting road
• flywheel
• spark plug
• counterweight
• inlet and outlet ports.

In the two-stroke engines, the piston moves from the top dead center (TDC) to the bottom dead center (BDC) and allows the fresh air enters the combustion chamber. During the upward stroke, the piston moves from the bottom dead center (BDC) to the top dead center(TDC). Due to this, the fuel-air mixture gas is compressed and the spark plug ignites the mixture. Then, this mixture expands and the piston moves downward.

b.) Four Stroke Engine

A four-stroke engine is an internal combustion engine with four different strokes: intake, compression, power, and exhaust to complete one operating cycle. While operating it requires two revolutions of the crankshaft. The four-stroke engine has the following parts:

• piston
• crankshaft
• connecting road
• flywheel
• inlet and outlet valves
• spark plug

2. According to the Cycle of Combustion

a.) Otto Cycle Engine

Otto cycle engine works on the principle of the otto cycle and that means combustion takes place at constant volume.

b.) Diesel Cycle Engine

The diesel cycle engine works on the principle of the diesel cycle and in this case the combustion takes place at constant pressure.

c.) Dual Combustion

Dual-Combustion or semi-diesel cycle engine works on the principle of both auto cycle and diesel cycle. In this case, the combustion takes place partially at constant volume and partially at constant pressure.

3. According to Arrangement of Cylinder

a.) Single Cylinder Engine

In this case, the Engine is having one cylinder and piston attached to the crankshaft. This type of engine is mostly used in motorcycles, scooters, go-karts, etc.

b.) Inline Engine or Straight Engines

In these types of engines, the cylinders are connected in a straight line or in a row along the length of the crankshaft. These are usually found in four, six, or eight-cylinder configurations.

c.) V-Engines

The V Engine is also known as the Vee engine sometimes. These engines have two cylinders banks inclined at an angle so that it forms a V shape and are connected with one crankshaft only.

d.) Opposed Cylinder Engines

These engines have two cylinders banks opposite each other and are connected with one crankshaft only. It is a form of V shape having an angle of 180 degrees.

e.) W-Engine

A W-engine is a type of engine in which the three or four cylinders are mounted on a single crankshaft and makes a W type of structure.

f.) Opposite Piston Engine

Opposite pistons engines have a piston at both ends of the cylinder and there is no cylinder head.

g.) Radial Engines

In radial Engines, the pistons are positioned in such a way that it makes a circular plane around the central crankshaft. The connecting rods of the piston is attached to the master rod which in turn connected with the crankshaft.

4. According to the speed of the Engine

a.) Low-speed Engine

Low-speed engines are defined as those types of engines which are having a range of 80–120 revolutions per minute

b.) High-speed Engine

High-speed engines are defined as those types of engines which are having a range of 900–1200 revolutions per minute.

c.) Medium speed Engine

High-speed engines are defined as those types of engines which are having a range of 250–1200 revolutions per minute.

5. According to the Method of Ignition

a.) Spark-Ignition Engine

Spark Ignition is a type of petrol engine in which combustion of fuel-air mixture is ignited by a spark plug.

b.) Compression-Ignition Engine

A Compressed Ignition engine is a type of diesel engine which is having a higher compression ratio than a spark-ignition engine. The diesel is then introduced which ignites spontaneously.

6. According to the Method of cooling of Engine

a.) Air-cooled Engine

b.) Water-cooled Engine

7. According to Valve Arrangement

a.) d valve arrangement

b.) L-head type Engine

c.) T-head type Engine

d.) F-head type Engine

8. According to Number of Cylinders

a.) Single Cylinder Engine

b.) Multi-Cylinder Engine

9. According to the method of Governing

a.) Hit and miss governed Engine

b.) Quality Governed Engine

c.) Quantity Governed Engine

10. According to Fuel Employed

a.) Oil Engine

b.) Gas Engine

c.) Diesel Engine

d.) Petrol Engine

e.) LPG Engine

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