What is the difference between petrol or gasoline and diesel fuels?

Answer 1

Diesel must be compressed and warmed to become combustible.

Gasoline simply ignites from the spark.

Longer answer

Both petrol (also known as gasoline) and diesel fuels are made in oil refineries. In a production process known as "cracking" they take crude petroleum oil - that has been extracted from oil-bearing rocks and shales which lie below the Earth's surface - and produce many different "fractions of distillation".

Gasoline and diesel are made from different blends of those crude oil "fractions" together with various kinds of chemical "additives" which are used to improve their performance as fuels.

Petrol is lighter in density and is not as "oily" as diesel.

In some countries diesel vehicle fuel is more expensive to buy than gasoline whilst, in other countries, diesel may be considerably cheaper to buy than gasoline, or their prices may be very similar. Such pricing differences are caused by many factors, including the production capacity available from local refineries, the costs of bulk-transporting the fuels over long distances and, last but not least, the major differences between the percentages at which vehicle fuel taxes are levied by the governments in each country around the world.

Whilst diesel can give better fuel economy (miles per gallon or kilometers per liter) than petrol, the downside is that diesel engines usually cost more to manufacture than petrol engines, so a petrol-engined vehicle usually costs less money to buy than a similar make and model that has a diesel engine.