Diesel is a special liquid. 
Diesel is a liquid fuel. 


Diesel is a liquid fuel used in many engines. 
Most diesel comes from petroleum, which is oil from the ground. This is often called petrodiesel. Scientists make it by heating crude oil in a refinery. Other types are also being made. One type is biodiesel. This comes from plants like soybeans or rapeseed. 
Rudolf Diesel invented the engine around 1892. He found it could run on many things. He even tested peanut oil in one engine. Today, diesel is standardized. This means it must meet set rules for quality. In the UK, people use colored tanks to keep fuels separate. 
Diesel fuel is a liquid used to power many machines. 

Most diesel comes from petroleum, which is oil found underground. This is often called petrodiesel. To make it, refineries use a method called fractional distillation. They heat crude oil to separate it into different parts. These parts contain carbon chains with 9 to 25 carbon atoms. 
Other types of diesel are being made from different sources. One type is biodiesel, which comes from living things. It is made from vegetable oils or animal fats. In Europe, rapeseed oil is a common source. In the United States, people often use soybean oil. 
A scientist named Rudolf Diesel invented the engine around 1892. He wanted to create a motor that could run on many things. At first, he tested crude oil from Pechelbronn. He also tried kerosene, petrol, and even lamp oil. In 1898, engines in Scotland and France used shale oil. These were used because other fuels were too expensive. 
Today, diesel must follow strict rules called standards. These ensure the fuel is high quality and safe. In the European Union, the standard is called EN 590. Most diesel in North America is now ultra-low-sulfur diesel. This type has very little sulfur in it. 
Diesel fuel, often called diesel or diesel oil, is a liquid fuel designed for diesel engines. These are a specific type of internal combustion engine. Unlike gasoline engines, they do not use a spark to ignite the fuel. Instead, they rely on a process called compression ignition. This happens when the engine compresses inlet air until it becomes very hot. When fuel is injected into this hot, compressed air, it ignites spontaneously. 
The most common form of this fuel is petroleum-derived diesel, sometimes called petrodiesel. It is produced in oil refineries through a process called fractional distillation. During this process, crude oil is heated at atmospheric pressure to separate it into different parts. This creates a mixture of carbon chains, typically containing between 9 and 25 carbon atoms per molecule. To improve the fuel, refineries use a method called hydrodesulfurization to remove sulfur. Because "straight-run" diesel is often in short supply, refineries use cracking technologies like visbreaking and coking. These methods convert heavier, less useful oil fractions into diesel. Finally, refineries may add kerosene to modify the fuel's viscosity, which is its thickness.
Scientists are also developing alternative types of diesel that do not come from petroleum. One major alternative is biodiesel, which is made from vegetable oils or animal fats, known as biolipids. This is created through a chemical process called transesterification. In this process, oils are reacted with methanol to form fatty acid methyl esters, or FAME. In Europe, rapeseed oil is a common source, while soybean oil is frequently used in the United States. 
The history of diesel fuel begins with the German inventor Rudolf Diesel. Around 1892, he invented the compression-ignition engine. Diesel originally believed his motor could run on almost any fuel in any state of matter. His early experiments involved crude oil from Pechelbronn, but he found it too viscous, or thick. He moved on to testing kerosene, petrol, and various types of lamp oil. 
As engine technology advanced, fuel quality became more important. In the 1930s, the introduction of motor-vehicle engines like the Mercedes-Benz OM 138 required higher-quality fuels. Before standardization, engines often ran on cheap fuel oils or mixtures of petrol and kerosene. After World War II, the first modern high-quality standards were introduced, such as DIN 51601. By 1993, the EN 590 standard replaced older rules in the European Union. Today, most diesel in North America and Europe is ultra-low-sulfur diesel (ULSD). This type has substantially lowered sulfur content to meet modern requirements.
To keep different fuels safe, many regions use specific colors for storage. In the United States, diesel is often kept in yellow containers to distinguish it from blue kerosene containers or red petrol containers. In the United Kingdom, diesel is normally stored in black containers. This helps prevent people from putting the wrong fuel into a vehicle. 
Chemical additives are also used to ensure the fuel works well in different environments. For example, ethylene-vinyl acetate (EVA) is added as a "cold flow improver." Adding between 50 and 500 ppm of EVA helps prevent wax crystals from blocking fuel filters in cold weather. Other additives, such as antioxidants and antifoaming agents, are added at much lower levels, between 5 and 50 ppm. These additives help manage the specific chemical composition of the fuel. 
🖼️ Images & Media (6)
More to explore
✨ What else?
Related topics you might enjoy
🔬 Go deeper
More advanced topics to explore
What is Nepedia?
A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.