The many names used to describe the fuel that powers a vehicle can be confusing at times. One can distinguish three main categories of fuel : Diesel, Petrol and Fuel. This article aims to explain the differences between them.

Diesel and gasoline primarily differ in terms of their chemical composition. While both are derived from petroleum, gasoline is a mixture of lighter hydrocarbons, whereas diesel consists of heavier hydrocarbons.

The combustion of fuel within the engine also varies between engines, leading to differences in how they produce energy and how they are used.

Diesel is used in diesel engines, in which the extremely high air compression generates high temperatures that result in the spontaneous ignition of the air/fuel mixture. Diesel is known for its high energy density, making it efficient for internal combustion engines.

It is primarily used in various types of vehicles, including trucks, buses, trains, and some light-duty utility vehicles. Diesel is prevalent in long-haul freight transport, particularly in heavy-duty trucks. Diesel trucks are a cornerstone of long-distance freight transport due to their energy efficiency and capacity to carry heavy loads.

In petrol engines, the air/fuel mixture is ignited by a spark plug. Petrol engines are known for offering good performance, especially at high RPMs (revolutions per minute). This suits light-duty vehicles, such as passenger cars, which are often used for urban commuting and road trips. As a result, petrol is primarily used as fuel for light-duty vehicles.

Petrol engines typically produce fewer nitrogen oxides (NOx) and fine particulate matter than diesel engines, making them a more favourable choice from a local emissions' perspective. However, petrol often produces higher carbon dioxide (CO2) emissions per unit of energy produced, which has implications for climate change.

Fuel and gas is a generic term including both diesel and petrol.

Originally, “gas” started being used as a shorter term for “gasoline” in the US. As petrol/gasoline is the main fuel source in the US (over 95% of cars run on petrol), it also started to be used as the generic term. This is why some people use gas as a synonym for fuel.

It's essential to note that trends are evolving. Electric and hybrid vehicles are gaining popularity due to their energy efficiency and reduced environmental impact.

On the other hand, compressed natural gas (CNG), liquefied natural gas (LNG) and hydrogen (H2) are increasingly being used as alternative fuels in some freight vehicles, particularly in public transportation fleets and trucking fleets. They are considered more environmentally friendly options compared to diesel.