What is the Mechanism behind Internal Combustion Engines?

The Internal Combustion Engine operates by igniting fuel and air inside the engine to move pistons and generate power.

The engineering behind the Internal Combustion Engine (ICE) is truly remarkable.

It operates by igniting fuel and air inside the engine to move pistons and generate power.

The basic principle is that when a small amount of fuel (such as gasoline, diesel, natural gas, or bio-diesel) is ignited in a confined space, it releases a large amount of energy which can be harnessed for propulsion.

Hybrid electric components can also be combined with ICE to increase fuel efficiency or hybrid plug-in electric systems to expand the range of these vehicles.

The two main types of ICE are the 4-stroke, which is used in cars and other modern vehicles, and the 2-stroke, which is used in lawn mowers and mopeds.

Efficient timing is crucial for engines with more than one stroke to operate smoothly and effectively.

So, how do these engines actually work?

The 4-stroke engine

A 4-stroke engine is typically a multi-cylinder engine with cylinders arranged in three different ways: inline, V, or flat.

The cylinder is the heart of the engine, and the piston moves up and down inside the cylinder to compress a mixture of fuel and air that is drawn in when it moves down.

As a beginner mechanic, I was taught that the process of engine operation can be summed up by the phrase “suck, squeeze, bang, blow.”

What does this mean?


The piston, which is equipped with a ring to ensure a perfect seal, starts at the top and moves down to fill the cylinder with air and gasoline when the intake valve opens.

The air-to-gasoline ratio is very small.

Throughout the engine’s movement, the sump provides lubrication and oil to ensure smooth operation.


The piston then moves back up the cylinder to compress the fuel/air mixture.

Compression increases the flammability of the mixture, making the explosion more powerful.


At the top of its stroke, the piston reaches the spark plug (which sparks when an electrical charge is passed through it) to ignite the gasoline.

The gasoline charge in the cylinder explodes, producing hot gas that pushes the piston back down.


As soon as the piston hits the bottom of its stroke, the exhaust valve opens.

The crankshaft (which converts the pistons’ linear motion into rotational motion to ensure all pistons are synchronized) drives the piston back up with the help of a connecting rod.

This pushes the exhaust gases up the cylinder, out the exhaust valve, and down the tailpipe.

The 2-stroke engine

A two-stroke engine is very simple to construct and operate in its purest form.

It has just three major moving parts, all of which are also found in the alternative 4-stroke engine: the piston, connecting rod, and crankshaft.

However, there are some differences, such as a reed valve.

The two-stroke engine is more complex than the four-stroke engine because some phases occur simultaneously, making it difficult to distinguish when one ends and the next begins. This type of engine uses both the crankcase and cylinder to carry out all the elements of the Otto cycle in only two strokes of the piston. Due to this, the two-stroke engine is lighter, simpler, and potentially has a greater power boost, firing every revolution, compared to the four-stroke engine, which fires every other revolution.

The first phase, called “Suck,” occurs when the fuel/air mixture is drawn into the crankcase by the vacuum created during the piston’s upward stroke. During the downward stroke, “Crankcase Compression” takes place, causing the valve to close due to crankcase pressure, compressing the fuel mix in the crankcase. “Exhaust” occurs near the end of a stroke when the piston reveals the intake port, allowing the compressed mix in the crankcase to flow around the piston into the main cylinder, which pushes the exhaust gases out the exhaust port. However, this process may result in some fuel mix being wasted. During “Compression,” the piston goes back up and compresses the fuel mix, while another intake stroke is carried out beneath it. Finally, in the “Power” phase, when the stroke reaches the top, the spark plug ignites the mix, which expands, driving the piston downward to complete the cycle.

The internal combustion engine revolutionized the world of transport. Unlike its external counterparts, such as the steam train, the internal combustion engine does not emit significant amounts of steam or by-products. However, with the growing green movement and the rise of electric cars, the internal combustion engine will eventually become a thing of the past. Tesla is among the major producers of high-end electric cars, and even everyday brands like Nissan and Renault are releasing such vehicles. Nevertheless, understanding how your car’s engine works and what happens to the fuel you put into it every week is valuable knowledge.


1. What is an internal combustion engine?

An internal combustion engine is a type of engine that converts the energy from fuel into mechanical energy through combustion, or the burning of fuel. It is commonly used in cars, trucks, boats, and other vehicles.

2. How does an internal combustion engine work?

An internal combustion engine works by compressing a mixture of air and fuel in a cylinder. This mixture is ignited by a spark plug, causing a controlled explosion that pushes a piston down, which in turn rotates a crankshaft. This rotational energy is transferred to the wheels of a vehicle or used to power other machinery.

3. What are the different types of internal combustion engines?

The two main types of internal combustion engines are the gasoline engine and diesel engine. Gasoline engines use spark plugs to ignite a mixture of gasoline and air, while diesel engines compress air and then inject fuel into the compressed air, causing it to ignite.

4. What are the parts of an internal combustion engine?

The main parts of an internal combustion engine include the cylinder, piston, crankshaft, camshaft, valves, fuel injectors or carburetor, and spark plugs. Each part has a specific function in the combustion process.

5. How efficient is an internal combustion engine?

The efficiency of an internal combustion engine depends on various factors, such as the type of fuel used, the design of the engine, and the operating conditions. Generally, gasoline engines are less efficient than diesel engines, with an efficiency range of 15-25%, while diesel engines have an efficiency range of 30-50%.

6. What are some alternative forms of engine technology?

Alternative forms of engine technology include electric motors, hydrogen fuel cells, and hybrid engines that combine the use of an internal combustion engine with an electric motor. These technologies offer the potential for improved efficiency and reduced emissions compared to traditional internal combustion engines.

Rate article
Add a comment