How does an IC engine work? An In-depth Analysis

working of an ic engine

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Modern machines are humanity’s greatest invention and there is no second thought about it. Right from the invention of the wheel in 2800 BC to the invention of automobiles, the human race has achieved success in all rounds of life.

It is down to the influx of engineering and technology that has enhanced transportation and has made it faster and more efficient today. 

In this article, we are going to understand the key that helps function the modes of transportation such as vehicles, ships, aeroplanes, and trains. It is called the Internal Combustion Engine. We will be focusing on the working of an IC Engine. 


In the early days, external combustion engines such as steam engines and gasoline engines were used, but they weren’t as efficient. 

In 1878, when Rudolph Diesel decided to create an engine with higher productivity and efficiency, diesel engines came into the world. 

As an internal combustion engine, it was quite efficient but with time, it evolved into a cleaner and a better version of itself. Today, new inventions and advancement in the field of internal combustion engines have changed the way of transportation.

The Strokes of the IC Engine

In the principle of working of an IC engine, the term stroke has three related meanings that help you to understand the working of an IC engine.

Strokes in the Power Cycles

There are four types of strokes i.e the induction (intake) stroke, the compression stroke, the combustion (expansion) stroke, and the exhaust stroke. These are the strokes that are commonly used in a four-stroke engine.

Types of Power Cycles

The cycle utilized by a piston engine is portrayed by the number of strokes to complete a cycle. 

The most widely recognized engines are the two-stroke and the four-stroke. More uncommon designs incorporate five-stroke, six-stroke and two-and-four stroke. 

Stroke Length

The distance travelled by the piston inside the cylinder with the completion of each cycle.

The Working of a Two-Stroke Engine

An internal combustion engine is used in two piston strokes, unlike four-stroke engines that functions with four-piston strokes. 

Commonly used in lower-power applications such as chainsaws, lawn-mowers, dirt bikes, etc. 

This is how a two-stroke engine looks like. 

ic engine - two stroke engine

A two-stroke engine comprises the compression stroke and the power stroke. In order to generate power, the two-stroke engine consists of a five-step process. 


The blend of the air or the fuel is at first brought into the crankcase by the vacuum which is made during the upward stroke of the piston. 

The engine consists of a poppet intake valve; however, numerous kinds of engines use a rotary valve assimilated in the crankshaft. 

Crankcase Compression

During the descending stroke, the poppet valve is compelled to get shut by the expanded pressure of the crankcase. The blend of the fuel is then packed in the crankcase during the rest of the stroke.


Near the completion of the stroke, the piston exposes the intake port, permitting the packed blend of air/fuel to escape around the piston into the main cylinder. This removed the fumes through the exhaust, which is generally situated on the contrary side of the cylinder. 

The unfortunate event that occurs is when some of the fresh fuel mixtures are ousted out as well. 


At that point, the piston starts to rise, driven by the force of the flywheel, and packs the fuel blend. Simultaneously, another intake stroke is going on underneath the piston. 


At the head of the stroke, the fuel mixture is ignited by the spark plug. The burning fuel grows, driving the piston to descend, to complete the cycle. All the while, another crankcase compression stroke is occurring underneath the piston.

Compared to a four-stroke engine, a two-stroke engine is lighter, efficient, consumes lower-grade fuel, and cost-efficient. The lighter the engine, the higher the power-to-weight ratio. However, these engines lack the mobility conceivable in four-stroke engines. 

Thus, two-stroke engines are ideal for ships, bikes, and lawnmowers whereas four-stroke engines are compatible with automobiles like cars and trucks. 

The Working of a Four-Stroke Engine

Internal Combustion Engines are very common and are found in all commercial and personal transportation systems across the world, this happens so because the working of an IC Engine is a basic necessity for any of these cars to work and function. 

The engine that is put in these cars is made of a four-stroke functioning engine, and that is what we are going to be looking at and will focus on its functioning scientifically.

Combustion takes place inside the engine internally as the gas mixes with the spark to create a combustion reaction inside the combustion chamber, this triggers the four-stroke pistons to work and get the engine working. 

This means that the internal combustion engine is responsible for converting the energy emitted from burning the fuel into mechanical energy which in turn makes the pistons of the engine move and gets the wheels of the car rolling. 

The idea is that the pistons move with the help of the gas expanding after pressure is applied, this, in turn, reaches the turbine and forces it to move because of the heat applied to it through expanding, when this turbine gets moving, the pistons attached to them also move and helps the engine to run.

In a four-stroke engine, an inlet gives way to the fuel, which then gets burn and its heat expands and reaches the turbines that in turn rub the pistons and power the engine to move, while the excess heat and vapor waste particles go to the exhaust pipe right outside the vehicle’s outlet.

For completing one cycle of combustion, the pistons need to perform four total strokes.

The job of igniting the spark to the fuel is of the ‘spark plug’, it slightly causes a spark to ignite the entire fuel.

The reaction which takes place in the combustion chamber is called an exothermic reaction which happens after a fossil fuel as petrol or diesel reacts with the ignition inside the engine.

It releases a lot of heat and energy which is the characteristic of this exothermic reaction. 

Having an IC Engine has its benefits, the #1 benefit being the fact that the four-stroke piston engine is the most efficient as compared to other engines and is the ideal choice to put in daily commuting vehicles as it gives the best fuel efficiency too.

Ultimately incurring lesser costs on fuel consumption, so in comparison to gas turbine engines, internal combustion engines are much better and are also portable, unlike gas turbine engines.

 If you found this informative, we’ve dedicated an entire hybrid and electric course for you. Make sure to check it out.

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