IC Engine: Diagram, Parts, Working, Types and Applications

In this post, we will going to learn what is ic engine and how it works. This article will also go over the components, nomenclature, advantages, and uses of IC engines.

What is IC Engine?

It is a type of engine that produces mechanical energy from the thermal energy stored in fuel. Internal combustion engines work by compressing and burning fuel in a small area, known as a cylinder, which forces a piston to move.

In this engine, fuel and air are mixed, combusted and burned within a combustion chamber. The high-pressure gasses produced apply force on a piston, which converts the pressure into rotational motion via a crankshaft. It is then used to power many types of vehicles, including automobiles, motorbikes, generators, and aircraft.

There are different types of IC engines, including gasoline engines and diesel engines, which each have a different combustion method and characteristics.

Before moving onto the types, lets understand the basic components of ic engine.

Components of IC Engine

Following are the main components of ic engine:

#1 Camshaft

It is a shaft that consist of one or more cams attached to it, especially one operating the valves in an internal combustion engine. Camshaft converts the rotational motion into reciprocating motion.

#2 Exhaust Valve

During the exhaust stroke, this valve opens to allow exhaust gases to exit the combustion chamber.

#3 Intake Valve

During the intake valve, this valve opens to allow to enter the fresh air/fuel mixture into the combustion chamber.

#4 Intake Valve Bucket

It is a component installed top of the valve stem. It helps to transfers the motion from the camshaft to open and close the intake valve.

#5 Exhaust Valve Bucket

Similar to intake valve bucket, this component transfers the motion from the camshaft to open and close the exhaust valve.

#6 Spark Plug

Spark plug is a mechanism that starts the combustion process by igniting the air-fuel mixture in the combustion chamber. It has a small electrode at its tip that is connected to the ignition system and produces electric spark.

#7 Piston

The function of a piston to transmit the force to the crankshaft through connecting rod from the expanding gas in the cylinder.

It is a cylindrical component that travels up and down inside the cylinder. It is usually driven by the force generated by the combustion process.

#8 Piston Pin

It joins the piston to the connecting rod, enabling the piston to revolve easily. It is also referred to as a wrist pin.

#9 Cylinder Head

They play a vital part in managing air flow into and out of the cylinders, as well as fuel deployment. The cylinder head also contains the combustion chambers, valves, and spark plugs.

#10 Connecting Rod

It is the component of a engine that connects the piston with the crankshaft. The connecting rod and the crank work together to transform the piston’s reciprocating motion into the crankshaft’s rotation.

#11 Cylinder Block

The cylinder block is also a key component in engine.  It is essential for lubrication, temperature management, and engine stability. It houses the cylinders and supports a variety of engine components.

#12 Crankshaft

The crankshaft serves as the engine’s foundation. The crankshaft coverts the linear motion into a rotational motion and ensures that the engine runs correctly. It powers the transmission and, eventually, the wheels.

#13 Intake Manifold

The main function of intake manifold is to distribute the combustion mixture equally to each intake port in the cylinder head. Even distribution matters for improving engine efficiency and performance.

#14 Exhaust Manifold

The exhaust manifold collects and sends the exhaust gasses from the engine cylinders to the catalytic converter. In engines that use turbocharging, the turbocharger is located after the exhaust manifold.

Working of IC Engine

The operation of an internal combustion engine can be explained in the following steps:

#1 Intake Stroke

At the beginning of the intake stroke, the piston is at the top dead center (TDC). The intake valve opens, causing the piston to fall downward towards BDC.

During this stroke, the fuel-air mixture enters the engine cylinder through the open intake valve. This stroke is known as suction stroke. The piston stops when it reaches the BDC, ending the intake stroke.

#2 Compression Stroke

During this stroke, the intake and exhaust valves remain closed while the piston approaches TDC. The pressure inside the cylinder rises as the air or mixture is compressed, reaching its peak as the piston approaches the TDC.

In gasoline-powered engines, the combustion process is started by producing a spark. While in diesel engines, combustion is initiated by injecting fuel into the highly compressed air.

#3 Power Stroke

The intake and exhaust valves stay closed during this stroke. The air-fuel mixture starts to burn at the end of the compression stroke, which causes the cylinder pressure to rise significantly. This greater pressure forces the piston lower to the BDC.

#4 Exhaust Stroke

As soon as the piston hits BDC, the exhaust stroke begins. The exhaust valve opens during this stroke, enabling the piston to travel from BDC to TDC.

When the piston moves in this way, most of the exhaust gasses are successfully released from the cylinder and directed into the exhaust pipes.

This procedure completes one engine cycle. Afterwards, the engine repeats intake, compression, power, and exhaust in a continuous cycle.

Nomenclature of IC Engine

Here are some terms and nomenclature associated with engines to help you better understand their working principle.

#1 Bore

The nominal inside diameter of an engine cylinder is known as the cylinder bore. It is identified by the letter d and measured in millimeters (mm).

#2 Piston Area

The piston area is the area of the circle whose diameter equals the cylinder bore. It is measured in square centimeters (cm²) and denoted by the letter A.

It is given by A = πd²/4

#3 Top Dead Centre

Top dead center (TDC) refers to the extreme position of the piston at the top of the cylinder in a vertical engine.

#4 Bottom Dead Centre

Bottom dead center (BDC) refers to the piston’s extreme position at the bottom of the cylinder of the verticle engine.

#5 Stroke

In other terms, the stroke is the distance traversed by the piston between TDC and BDC. The stroke is the greatest length of time the piston travels in a single direction within the cylinder.

It is represented by the letter L and has a millimeter (mm) value.

#6 Clearance Volume (Vc)

The clearance volume is the volume in the cylinder that is present above the piston’s top when the piston is at its top dead center.

It is represented in cubic centimeters (cc) and is designated by the letter Vc.

#7 Swept Volume (Vs)

The volume that the piston covers as it moves from TDC to BDC is known as the swept volume. In other words, the volume that the piston sweeps during a single stroke is referred to as the swept volume or piston displacement.

It is given by Swept Volume (Vs) = Vs = AxL

#8 Compression Ratio

The volume of the piston at bottom dead center divided by the volume at top dead center is known as the compression ratio.

It is given by, Compression ratio = Maximum Cylinder Volume/ Minimum Cylinder Volume

Compression ratio = (Swept Volume + Clearance Volume)/ Minimum Cylinder Volume

The compression ratio for petrol engines typically ranges from 5:1 to 10:1, whereas diesel engines range from 12:1 to 22:1.

#9 Mean Effective Pressure

Mean effective pressure is the average of the pressures that are applied to the piston during thermodynamic operations.

It is given by,

Mean Effective Pressure = Torque × Number of revolution for the power stroke × 2π / Displacement

Classification of IC Engine

IC engines are classed according to the number of strokes, fuel type, and engine cylinder arrangement. Below is a short summary of this classification of ic engines:

Based on Number Strokes

#1 Two-Stroke Engine

It is a type of internal combustion engine in which a power cycle is completed with two piston strokes. It is less fuel-efficient than the four-stroke engine, but it is still simpler.

Two-stroke engines are generally used in small power tools, scooters, and some motorcycles. They feature a simpler design than four-stroke engines.

#2 Four-Stroke Engine

In the case of a four-stroke engine, it is a type of internal combustion engine that completes four distinct phases in just one complete cycle: intake, compression, power, and exhaust at the same time.

Four-stroke engines are frequently found in motorbikes, cars, and other types of vehicles. Compared to two-stroke engines, the design of these engines is more complex.

Based on Fuel Type

#1 Spark-Ignition Engines (SI Engines)

These engines run primarily on gasoline. In SI engines, combustion begins with an electric spark, which ignites the fuel-air mixture in the cylinder.

SI engines are widely used in passenger automobiles, motorbikes, and light planes. These engines are recognized for their strong power output, smooth operation, and minimal emissions.

#2 Compression-Ignition Engines (CI Engines)

These engines run mostly on diesel fuel. In CI engines, combustion begins when high pressure and temperature are present in the cylinder, without an external ignition source.

CI engines are often seen in stationary and marine power applications, as well as in heavy-duty vehicles like trucks, buses, and construction equipment. These engines have become famous for their long lifespan, excellent fuel efficiency, and cheap operating costs.

Based on Engine Configuration

#1 Inline Engine

A inline engine is characterized by the fact that it consists of cylinders that are arranged in a straight line. This arrangement is widely used in compact automobiles and motorcycles.

#2 V-Engine

These engines feature two rows of opposed cylinders joined in a ‘V’ design. This layout is used by both V6 and V8 engines. This layout is typically seen in larger automobiles and trucks.

#3 Flat Engine

A flat engine is sometimes called a horizontally opposed engine. In this configuration, cylinders are arranged in a horizontally opposed configuration, with two banks facing each other. Aircraft and some very fast sports automobiles often employ this design.

#4 Radial Engine

Radial engines have cylinders arranged in circles around the crankshaft in a circular pattern, and they work by rotating the crankshaft. This layout is often utilized in aircraft.

Advantages of IC Engine

Following are the advantages of IC engine:

1. These types of engines are smaller in size than external combustion engines.
2. IC engines feature a higher power-to-weight ratio and are safer to operate.
3. Compared to external combustion engines, internal combustion engines are more efficient.
4. There is no possibility of fluid leaking in an IC engine.
5. These engines require little maintenance and can start quickly.
6. IC engines consume less lubrication than external combustion engines.

Disadvantages of IC Engine

Following are the disadvantages of IC Engine:

1. These engines have a restricted range of fuel options, mostly high-quality gaseous and liquid fuels.
2. IC engines often require expensive fuels such as gasoline or diesel.
3. Typically, IC engine emissions are higher than those of external combustion engines.
4. These are not appropriate for producing huge amounts of power.
5. Fuel detonation causes noise in reciprocating internal combustion engines.

Applications of IC Engine

Following are the most common applications of ic engines:

1. IC engines are commonly found in automobiles, including cars, buses, trucks, and motorcycles.
2. These engines are also employed for propulsion in tiny airplanes and helicopters.
3. In marine applications, including as ships, boats, and submarines, IC engines are employed.
4. Excavators, bulldozers, and cranes are all examples of construction machinery that use internal combustion engines.
5. IC engines can also power a variety of small-scale vehicles, including motorized scooters, and mopeds.

Wrapping It Up

That’s it. Thanks for reading. I hope I have covered everything about the “IC Engine Working and Its Parts”. It would be helpful if you could let me know if there was anything I missed or if you have any doubts about anything I wrote.

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Frequently Asked Questions (FAQ)

Following are some of the most common questions that usually people ask about ic engines.