A 4 Stroke Engine With Important Terms & Diagrams.

Last updated on July 14th, 2023 at 01:47 pm

A 4 Stroke Engine With Important Terms & Diagrams. you will see the working of petrol and diesel engine. along with the diagram and related videos. that will help you to understand better.

                                                                                 A 4-Stroke Engine.

In this article, we will learn about a 4-stroke engine & how the machine works?

• First off this entire article will be very useful for engineering students.
• Read the complete article to get the most out of it.
• I have provided a couple of useful links for the students.

Content –

1. Introduction.
2. Working Petrol & Diesel Four-stroke engine.
3. Important Terms related to the engine.

Introduction

• As we know that almost all automobiles use engines.
• The engine has become the most essential part of humans as well.
• But most of us don’t know how the engine works.
• The engine converts the explosive power of the fuel & air mixture into rotating power.
• And further, this power is used to run cars, bikes & machines.
• Count Nicolas Otto a German engineer first successfully applied the 4-stroke principle.
• A four-stroke engine is almost used in all types of automobiles & factories.

Working A 4-stroke engine (Petrol).

1. Suction Stroke –

• In this stroke, the piston moves towards TDC to BDC.
• The Inlet valve opens slightly before the piston moves towards BDC & remains open till the piston reaches BDC.
• As the piston moves towards BDC, it creates a vacuum inside the cylinder.
• Due to this Air/Fuel mixture comes inside the cylinder via an Inlet manifold through the carburettor.
  
• The Inlet valve closes when the piston reaches the BDC.
• End of suction stroke.

2. Compression Stroke –

• In this stroke, both the inlet & exhaust valve remain closed.
• It happens before when the piston starts moving from BDC to TDC.
• When the piston reaches TDC air gets compressed completely.
• And the temperature of compressed air rises from 250° to 350° Celsius.
• End of the compression stroke.

3. Power Stroke –

• In this Stroke again both valve Inlet & exhaust valve remain close.
• Then spark plug ignites the air/fuel mixture supplied by the carburetor.
• Spark creates an explosion in the engine which moves the piston towards BDC.
• This helps to turn the crankshaft.

4. Exhaust Stroke.

• This exhaust valve opens slightly before the piston moves towards TDC.
• As the piston moves towards TDC, it moves to expel the burned gases outside.
• With the help of an exhaust manifold.
• This cycle repeats several times to keep the engine in running condition.
• End of the exhaust stroke.

Working A 4-stroke engine (Diesel).

1. Suction Stroke.

• In this stroke, the piston moves towards TDC to BDC.
• The Inlet valve opens slightly before the piston moves towards BDC & remains open till the piston reaches BDC.
• As the piston moves towards BDC, it creates a vacuum inside the cylinder.
• Due to this only air comes inside the cylinder via the Inlet manifold.
• The Inlet valve closes when the piston reaches the BDC.
• End of suction stroke.

2. Compression Stroke –

• In this stroke, both the inlet & exhaust valve remain closed.
• It happens before when the piston starts moving towards TDC.
• When the piston reaches TDC air gets compressed completely.
• And the temperature of compressed air rises from 600° to 800° Celsius.
• End of the compression stroke.

3. Power Stroke –

• In this Stroke again both valve Inlet & exhaust valve remain close.
• Diesel fuel is injected at high temperatures and pressure with injectors.
• As injected fuel is injected into the cylinder it comes in contact with hot air.
• An explosion takes place inside the cylinder.
• This moves the piston in a downward direction to rotate the crankshaft.
• End of the power stroke.

4. Exhaust Stroke.

• This exhaust valve opens slightly before the piston moves towards TDC.
• As the piston moves towards TDC, it moves to expel the burned gases outside.
• With the help of an exhaust manifold.
• This cycle repeats several times to keep the engine in running condition.
• End of the exhaust stroke.

Important Definitions of A 4-stroke engine.

1. Stroke.

When the piston moves from TDC to BDC once or vice versa is known as stoke.

2. Top Dead Center (TDC).

It’s the topmost position of the piston in the cylinder when the piston moves towards TDC.

3. Bottom Dead Center (BDC).

It’s the bottom-most position of the piston in the cylinder when it moves towards BDC.

4. Carburettor.

The carburettor is a device used to mix petrol & air for combustion.

5. Spark plug.

It’s an electronic device that produces a spark to ignite the air/fuel mixture.

6. Fuel injector.

Injectors are used in diesel engines to spray diesel at high temperatures & pressure into cylinders.

A 4-stroke engine video (petrol).

A 4-stroke engine video (Diesel).

Diesel engine video in English.

In this blog, we have tried to explain how a 4-stroke petrol and diesel engine works. I hope that now you can understand how a 4-stroke engine works.

Thank You

Avinash Sharam (Blogger)