Difference Between Petrol and Diesel

The key difference between petrol and diesel is that petrol contains lighter hydrocarbons whereas diesel contains heavy hydrocarbons. Petrol and diesel are important as fuels in our automobiles.

However, many people are not aware of the differences between the two though they are aware of their price difference and the mileage that these two different petroleum products give. This article aims to highlight the difference between petrol and diesel to enable people to go for a fuel that suits their requirements.

CONTENTS

1. Overview and Key Difference
2. What is Petrol
3. What is Diesel
4. Side by Side Comparison – Petrol vs Diesel in Tabular Form
5. Summary

What is Petrol?

Petrol mainly consists of light hydrocarbons ranging from C5 to C12. Cars and other vehicles use an inflammable liquid as the fuel, which is a blend of these small hydrocarbons.  A typical petrol mixture contains paraffin, naphthenes, aromatics and olefins. Both petrol and diesel are byproducts of crude oil refining at different temperatures.

Moreover, petrol separates from crude oil at a temperature range of 35 degrees to 200 degrees centigrade. A synonym for petrol in the western world is gasoline. When considering the energy content of petrol, it contains about 46.7 megajoules per litre.

What is Diesel?

Diesel contains about 75% saturated hydrocarbons and 25% aromatic hydrocarbons. Diesel contains hydrocarbons with longer carbon chains than petrol and is thus less volatile. This is also because of the additives present in diesel. When considering the energy content, diesel contains about 38.6 megajoules per litre (while petrol contains about 46.7 megajoules per litre). This means diesel has very high power and this is precisely why it is useful in heavy vehicles that require more power. Diesel is also more fuel efficient giving out a mileage that is nearly 50% more than petrol. This explains the desire of the people to go for diesel engines.

In some countries like India, diesel is the most common fuel in transportation. Therefor, they subsidise diesel than other fuels. This makes it cheaper than petrol. But in the western world, it is priced at par with petrol, but still, people prefer it over petrol as it gives more mileage than petrol.

What is the Difference Between Petrol and Diesel?

Petrol vs Diesel
A liquid fuel mainly consists of light hydrocarbons ranging from C5 to C12.	A liquid fuel consist of heavy hydrocarbons than C12.
Flammability
Highly inflammable than diesel.	Lesser inflammable than petrol.
Volatility
Highly volatile than diesel because it contains light hydrocarbons.	Less volatile than petrol because it contains heavy hydrocarbons.
Energy Content
The energy content of petrol is about 46.7 megajoules per litre.	The energy content of diesel is about 38.6 megajoules per litre.

Summary – Petrol vs Diesel

Both petrol (also called gasoline in the western world) and diesel are by-products of crude oil. The difference between petrol and diesel is that petrol contains lighter hydrocarbons whereas diesel contains heavy hydrocarbons.

Reference:

1. “Gasoline.” Wikipedia, Wikimedia Foundation, 14 May 2018. Available here  
2. “Diesel Fuel.” Wikipedia, Wikimedia Foundation, 12 May 2018. Available here  

Image Courtesy:

1.’Petrol pump mp3h0354’By Rama – Own work, (CC BY-SA 2.0 fr) via Commons Wikimedia  
2.’Red diesel tank’By Meena Kadri (CC BY 2.0) via Commons Wikimedia