Internal Combustion Engine: Definition, and Working

What is internal combustion engine?

An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel with an oxidizing agent (usually air) takes place in a combustion chamber which is an integral part of the working fluid flow circuit.

In an internal combustion engine, the expansion of the high temperature and high-pressure gases produced by combustion exerts a direct force on some components of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle.

This force moves the component over a distance and converts chemical energy into useful work. This replaces the internal combustion engine for applications where the weight or size of the engine is important.

The term internal combustion engine usually refers to an engine in which combustion is intermittent, such as the more popular four-stroke and two-stroke piston engines, along with variants such as the six-stroke piston engine and the rotary Wankel engine.

The second class of internal combustion engines uses continuous combustion: gas turbines, jet engines, and most rocket engines, each of which is an internal combustion engine on the same principle as previously described.

Firearms are also a form of the internal combustion engine, although they are so specialized that they are usually treated as a separate category.

Who invented the Internal Combustion Engine?

In 1872, American George Brayton invented the first commercial liquid-fueled internal combustion engine. In 1876, Nicolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-stroke cycle engine. In 1879, Karl Benz patented a reliable two-stroke gas engine.

internal combustion engine

How does an internal combustion engine work?

Combustion, also known as burning, is the basic chemical process used to release energy from a fuel-air mixture. In an internal combustion engine (ICE), the fuel is ignited and burned inside the engine itself.

The engine then converts some of the energy from the combustion into work. The engine consists of a fixed cylinder and a moving piston.

The expanding combustion gases push the piston, which in turn rotates the crankshaft. Ultimately, this movement drives the vehicle’s wheels via a transmission system in the drive train.

Two types of internal combustion engines are currently manufactured: the spark ignition gasoline engine and the compression ignition diesel engine.

Most of them are four-stroke, which means it takes four piston strokes to complete a cycle. The cycle comprises four different processes: intake, compression, combustion, and power stroke, as well as exhaust.

Spark ignition gasoline and compression ignition diesel engines differ in the way they deliver and ignite fuel. In a spark-ignition engine, the fuel is mixed with air and then inducted into the cylinder during the intake process.

After the piston compresses the fuel-air mixture, the spark ignites it and causes combustion. The expansion of the combustion gases pushes the piston during the power stroke. In a diesel engine, the air is inducted into the engine and then compressed.

Diesel engines then spray the fuel into the hot compressed air at a suitable, measured rate, causing it to ignite.

Applications of IC Engine

Internal combustion engines are the most broadly applied and widely used power-generating devices currently in existence. Examples include gasoline engines, diesel engines, gas-turbine engines, and rocket-propulsion systems.

IC engine has many applications like,

  • These are also used in automobiles, motorcycles, boats, and in a wide variety of aircraft and locomotives which demands very high power, such as jet aircraft, helicopters, and large ships.
  • IC engines are used for mobile propulsion in automobiles, equipment, and other portable machinery.
  • They are also used in generators.
  • The reciprocating engine of a car.

Classification of IC Engine

There are two kinds of internal combustion engines currently in production: the spark ignition gasoline engine and the compression ignition diesel engine. Most of these are four-stroke cycle engines, meaning four piston strokes are needed to complete a cycle.

IC engines can be classified on the basis of fuel used, thermodynamic cycle, type of ignition, type of cooling system, cylinder arrangement, method of charging, etc.  Now we study it in detail.

1) According to Cycle of Operation:

We know IC engines convert chemical energy into mechanical energy in cyclic operation. There are many thermodynamic cycles e.g. Carnot cycle, Otto Cycle, Diesel Cycle, Rankine cycle, etc. IC engines work on three cycles Otto cycle and Diesel cycle and the Dual cycle. So according to it, the IC engines can be classified into the following types.

1. Otto Cycle Engine:

It is also known as a spark-ignition engine or constant volume heat addition engine, Petrol engine, etc. In this cycle heat addition (fuel burn) and rejection (exhaust) takes place at constant volume and expansion and compression take place at isentropic. These engines give low power at high speed.

2. Diesel Cycle Engine

This is known as a compression-ignition engine, diesel engine, constant pressure engine, etc. In this cycle heat addition (fuel burn) takes place at constant pressure and heat rejection takes place at constant volume.  This engine gives high power at low speed.

3. Duel Cycle Engine:

The dual cycle is a combination of the Otto cycle and the diesel cycle. In this engine, heat addition takes place both at constant volume and constant pressure in some ratio.

Some engines work on the Stirling cycle and Ericsson cycle but these are not used commercially.

2) According to Type of Fuel Used:

Most of us know about these engines. These are petrol engines and diesel engines. Nowadays gaseous fuel like LPG, CNG, hydrogen, etc. is also used in IC engines. These engines are called non-traditional engines.

3) According to the Method of Charging:

The charging means how the admission of the fuel-air mixture takes place. This can be classified as follow.

  1. Natural aspirated engine:

In this engine, admission of the air-fuel mixture (SI Engine) or air alone (CI engine) takes place due to pressure difference inside the cylinder and atmospheric pressure.

2. Supercharged Engines:

In this engine, a separate compressor is used to the admission of charge inside the cylinder. This compressor is run using engine power (connected with the crankshaft with belt drive).

3. Turbocharged Engine:

This engine uses a turbine that draws air into the cylinder and runs by using exhaust gas power. It is also like supercharge but the compressor is run by a turbine which is rotated by exhaust gases.

4) According to Ignition:

In IC engine ignition of charge can take place in two ways. In the first one, a separate spark plug or any other device is used to ignite the fuel (Spark Ignition Engine) and the other one is fuel ignite due to heat generated during compression or fuel (Compression Ignition Engine).

So according to these methods, two engines are available spark-ignition engine or SI engine (Petrol Engine) and compression ignition engine or CI engine (Diesel Engine).

5) According to a type of Ignition System:

In petrol engines, we used a spark plug to ignite the fuel. This spark at the spark plug, produce by an ignition system. According to the ignition system, two types of engines are there. The first one is the battery ignition engine (use a battery to generate spark) and another one is a magneto ignition engine (use a small generator to generate spark).

6) According to Design of Engine:

  1. Reciprocating Engine:

In this type of engine, a piston is used which moves in reciprocating motion by using pressure force generated by the burning of fuel. The crankshaft converts this reciprocating motion into rotary motion. Most of the automobile engines are reciprocating type.

2. Rotary Engine:

In a rotary engine, a rotor is used. The pressure force generated by the burning of fuel is exerted on this rotor, which further rotates the wheel. The Wankel engine is one type of rotary engine. These engines are currently not used in automobile engines.

7) According to cooling:

Two types of cooling are used in IC engines, air cooling, and water cooling. So the engines are air-cooled engines or water-cooled engines. Both these cooling systems have their own advantages, which we will discuss later. Engine oil is also serving as a cooling medium.

8) According to stroke of engine:

We know that the stroke is the maximum distance a piston can travel inside a cylinder or between TDC to BDC. If an engine moves from TDC to BDC, it is called one stroke. If it returns to BDC it is called two strokes. A crankshaft makes one rotation in two strokes. According to it, three types of engines have been invented.

1. Two-stroke Engine:

In this engine, the crankshaft makes one rotation in one power stroke. This engine gives more power compare to others. It is used in shooters, ships, generators, etc.

2. Four-stroke engines:

This engine gives two crankshaft rotations in one power stroke. They give low power but high efficiency. It is used in cars, trucks, bikes, etc.

3. Six stroke engines:

These engines are in the development process. As the name implies, it will give three crankshafts rotation in one power stroke.

9) According to an arrangement of engine:

These engines can be better understood by diagram compare to words.

arrangement of engine

FAQs.

What Is Internal Combustion Engine?

An internal combustion engine (ICE) is a heat engine that uses an oxidizer (usually air) to burn fuel in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high temperature and high-pressure gases generated by combustion exerts a direct force on a component of the engine.

How Does An Internal Combustion Engine Work?

The engine consists of a fixed cylinder and a moving piston. The expanding combustion gases push the piston, which in turn rotates the crankshaft. After the piston compresses the fuel-air mixture, the spark ignites it, causing combustion. The expansion of the combustion gases pushes the piston during the power stroke.

Who Invented The Internal Combustion Engine?

In 1872, American George Brayton invented the first commercial liquid-fueled internal combustion engine. In 1876, Nicolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-stroke cycle engine. In 1879, Karl Benz patented a reliable two-stroke gas engine.

How To Classified Ic Engine?

There are two kinds of internal combustion engines currently in production: the spark ignition gasoline engine and the compression ignition diesel engine. Most of these are four-stroke cycle engines, meaning four piston strokes are needed to complete a cycle.

Read Also