Home STEM Car Engine Basics

Car Engine Basics

by Yule Xie


In the modern world most of us are familiar with cars. However, not all understand the variety of car engines that exist to make the beautiful vehicles on the road. Ever wondered what an “inline 4” or “V6” meant? This article will explore the difference between naturally aspirated and turbo engines and discuss the different types of cylinder alignment. First we must understand some background knowledge: gasoline engines operate through combustion, a process where the engine intakes air, compresses the air, and then uses that to burn the gasoline to create energy, movement, and exhaust which leaves the vehicle through pipes.



Cylinders and Horsepower

Don’t be mistaken – horsepower is not what you think!


In an engine the cylinder is one of the most crucial parts to recognize. This is because in order for combustion to happen the pistons must move through the cylinders. With the number of cylinders comes the concept of horsepower – a unit of power or the rate in which work is done. And, yes, a car is very, very powerful! To give a clear perspective:


1 Horsepower is 746 Watts

A powerful electrical applicant, like a microwave, is around 1100 watts

A common sedan or SUV is around 200 horsepower (~150,000 watts!)


The overall idea is simple – the more cylinders, the more powerful the engine, and thus the more horsepower. Also note: there are numerous ways the cylinders are aligned. In simple words, “Inline” represents a linear arrangement, “V Engines” denote cylinders away from each other at angles, and “flat” means the cylinders are apart on two sides of the engine.


Naturally Aspirated vs Turbo Engines


Now, the final topic. You have likely heard of “turbocharged” or saw a “T” after the engine configuration. Many new auto models have adapted to the idea of “Turbo” where instead of taking in air normally like in a “naturally aspirated” engine, more air is forced into the engine through compressing the already-exhausted air. In other words, combustion happens twice in a turbo engine. 


A benefit of this is that a smaller, turbo engine like a 2.0T with only 4 cylinders can match the power of a 3.0L naturally aspirated V6. Thus, fuel economy is also improved. However, maintenance may be more difficult as natural aspiration is more conventional.


Also Note – if you are a fan of the loud sound of engines – turbo would not be favorable as it reduces noises.

Works Cited and Image Credits












related articles

1 comment

Charlee Liu December 6, 2022 - 1:53 am

“more air is forced into the engine through compressing the already-exhausted air. In other words, combustion happens twice in a turbo engine.”

This is not true – more air is forced into the engine through a compressor which is driven by exhaust turbo. Because the density is higher for charged fresh air, more air mass is allowed for the same cylinder volume, thus more fuel can be injected so as the power.

In some cases, there is small amount of exhaust was re-directed back into cylinder by a system called EGR – exhaust gas recirculation. This is for emission control purpose,


Leave a Comment