Learn how your car engine work to better take care of it!

By Juliet Onyeachonam
Publish on May 16, 2019

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If you are looking for information on how car engines work, you should know that it takes thousands of completed combustion cycles to get your car engine running while you move from point A to point B. One combustion cycle on the other hand is made up of four strokes, intake, compression, combustion and exhaust.

As easy as turning a key or pushing a button to start a car is, there is actually a lot of works that have been put in and processes going on to make that happen.

If you have ever wondered how a car engine actually works, then today you are getting firsthand information about how car engines work from Naijauto.com.

For you to get from point A to point B hassle-free, your car engine completes what we call a combustion cycle.

Now, completion of several of these combustion cycles is what powers your car engine. In other words, the process of powering your car engine is called the combustion cycle.

A combustion cycle comprises four steps called ‘strokes’ (hence the name four-stroke engine).

1. Strokes involved in a combustion cycle

These four strokes involved in a complete combustion cycle include:        

  • Intake
  • Compression
  • Combustion
  • Exhaust

Further down, we will take a look at these four strokes and how they contribute to a car engine’s combustion cycle.

It will suffice to know that engines are powered by internal combustions which are small, controlled explosions taking place in a car's various cylinders. This is the effect of igniting a fuel-air mixture in the various cylinders of the engine. This process occurs thousands of times in a minute, helping the car to move.


The combustion cycle includes 4 phases, illustrated in this 4-stroke photo

>>> If you just leave your car in garage without check, rats might come for a visit! See How do I get rats off my car engine? in the post!

1.1. Intake

As the crankshaft moves, the pistons move up and down, reaching the valves mounted on the camshaft.

On one hand, as the piston moves down, the timing belt rotates the camshaft causing the valves mounted on it to open and release a fuel-air mixture. This process is called intake.

1.2. Compression

The compression stroke of a car engine occurs as the piston moves upward. This upward movement of the piston forces the fuel-air mixture released during the intake stroke into a tight space.

1.3. Combustion

Right after compression, just before the piston moves down again comes combustion. This occurs when the spark plug produces a spark to ignite the fuel-air mixture causing a small explosion. The effect of this small explosion forces the piston down rapidly, producing the needed energy to power the car engine.

1.4. Exhaust

Just as the piston reaches its lowest point, the valves of the exhaust system opens in readiness to expel the gases formed during combustion. As the piston moves back up, these gases are expelled via the exhaust valve. That completes the combustion cycle for one cylinder of a four-stroke engine.

As mentioned earlier, all four strokes involved in one combustion cycle are repeated thousands of time per minute to keep the car engine running. In understanding how car engines work, you should know that cars usually have multiple cylinders of different capacities.

Also cars have different layouts and configurations, all giving different power outputs, which will be discussed below.

2. Most common car engine layouts

There are varying car engine layouts one is likely to find on cars.

A car engine layout is determined by the arrangement of the different cylinders. Manufacturers use these different cylinder arrangements in a bid to add more power to their engines or to make sure the engines occupies smaller spaces.

The most common engine layouts include:

  • Straight
  • Inline
  • V- Shape
  • Flat

2.1. Straight Layout

In a straight car engine layout, the various cylinders are arranged in a straight line parallel to the car from front to back. The straight arrangement allows for more cylinders and is common in most powerful saloon cars such as the BMW and Mercedes.

2.2. Inline Layout

In this engine layout, the cylinders are arranged perpendicular to the car. They are placed side by side in upright positions across the engine bay. This arrangement is known to occupy a more compact engine space allowing for other engine component such as battery and radiator to be fitted around the cylinders.

This engine layout is common in most hatchbacks and portable family cars.


This BMW got an inline-six engine

2.3. V-shape Layout

In the V-shape engine layout, the cylinders are mounted on their sides at an angle of 60, with two rows facing outwards while being connected by the crankshaft at the base where it forms a "V".

This arrangement allows for more number of cylinders to be fitted into a smaller space providing more power. On that account, the V-shape car engine layout is common in supercars.

2.4. Flat Layout

In this case, the cylinders are arranged horizontally with two rows facing outwards.

The flat car engine layout is not very common but are highly placed because it offers a lower centre of gravity allowing for balance and easy handling. This kind of engine layout can be found in the Porsche 911 sports car where a flat six-cylinder engine was used.

>>> Having read through this part, can you now distinguish these two engine types? What are differences between the 6-cylinder engine and the V6 engine?

3. Engine Cylinder Configurations

Back in the days, it was believed that the more number of cylinder a car has, the greater its performance. However, that is no longer the case today. Car engines are now being fitted with powerful fuel injection systems and turbochargers making it possible for car engines with lesser number of cylinders to have greater performances.

As a take away read to our car engine layouts, we will also discuss the different car engine configurations out there.

  • Twin-Cylinder

Two cylinder engines are the rarest types of engine out there, reason being that they offer lower power output and capacity. However, these days auto manufacturers are using turbochargers to make very powerful twin-cylinder engines.

  • Three-Cylinder

The three-cylinder engines are found mostly on small cars. Thanks to the advent of turbochargers, they are now being used in larger hatchbacks such as the Ford Focus.

These three-cylinder engines are characterized by their burbling noise and shuddering vibration. That is as a result of their odd cylinder number which affects the engine's balance.


This Ford Focus is hiding a three-cylinder engine under the hood

  • Four-Cylinder

Four cylinder engines are the most common engine configurations out there. They are found on mostly mid-sized cars and are set in an inline layout. Ordinary, four cylinders offer good engine output which can further be enhanced with turbochargers.

  • Five-Cylinder

This configuration is also a rare type and just like three cylinders, they have shuddering vibration owing to their odd number of cylinders. The five cylinders are common in Volvos.

>>> We all know engine must be hot when operating but what about the cooling system? Read this to know when and when not to worry! Your engine is running hot: should you worry?

  • Six-Cylinder

The six-cylinder engine configuration is common in sports cars and other high-end cars. They are mostly setup in the V- shape engine layout.

Once upon a time, six-cylinder engines were not considered as being powerful but with the advent of turbochargers, they are now being regarded as very powerful engines. Hence, they are being used on sports cars.

  • Eight+ Cylinders

Amongst the different types of car engine configurations out there, the Eight+ cylinders engines are considered the most powerful. They produce large engine capacity and power output which is why they are found mostly on super cars.


Sixteen-cylinder engine for a Bugatti Veyron, unbelievable!

They are set up in the V-shape layout, hence they are referred to as V8, V10 or V12 engines. Even the Bugatti Veyron boasts of a sixteen cylinder engine.

>>> Find out more about Car maintenance tips and Car facts on Naijauto.com!

Juliet Onyeachonam

Juliet Onyeachonam is an enthusiastic car nut which is why she has turned that passion into a fantastic job by becoming a car blogger on NaijAuto.com. Juliet's blogs are a wealthy resource for information on car maintenance, driving tips and also how things pertaining to cars work.

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