Diesel fuel is used in many familiar vehicles and machinery such as trucks, long-distance buses, boats, generators, and construction equipment. Therefore, whenever diesel prices rise or fall, the cost of transporting goods, production, and many other services can be affected.
Although it appears quite frequently in fuel news, not everyone fully understands what diesel fuel is and why it remains so widely used.
What is diesel fuel?
Essentially, diesel fuel is a liquid fuel refined from petroleum and designed for use in diesel engines. These are internal combustion engines that operate on the principle of compressing air to very high pressure and temperature, then injecting fuel into the combustion chamber to create combustion.
This principle was invented in the late 19th century by the German engineer Rudolf Diesel. Compared to gasoline engines, diesel engines do not require spark plugs; instead, they utilize the heat generated during compression to ignite the fuel.
Thanks to these characteristics, diesel engines are often used for equipment requiring high power or continuous operation for extended periods. Diesel engines can easily be found in trucks, ships, construction machinery, forklifts, or backup power generator systems.
Principles and characteristics of diesel fuel
Compared to gasoline, diesel fuel has several distinct characteristics. First, diesel has a higher density, meaning it holds more energy in the same volume of fuel. This allows diesel engines to operate efficiently when pulling heavy loads or for long journeys.
Another notable point is that diesel has a significantly higher evaporation temperature than gasoline, typically ranging from 175 to 370°C. This results in less evaporation under normal conditions and greater safety during storage and transportation.
Furthermore, diesel fuel contains many long-chain hydrocarbon molecules. These molecules can form a thin oil film that helps lubricate certain parts of the fuel system. These characteristics make diesel a suitable choice for engines requiring high durability and load-carrying capacity.
Common types of diesel fuel in Vietnam
In Vietnam today, the two most commonly used types of diesel fuel are DO 0.005%S and DO 0.25%S. The main difference between these two types lies in the sulfur content of the fuel.
DO 0.005%S has a lower sulfur content and is therefore commonly used for road vehicles such as trucks and buses, or industrial machinery. Meanwhile, DO 0.25%S has a higher sulfur content and is typically used for certain industrial equipment or marine vessels.
In recent years, the general trend in the energy industry has been to reduce the sulfur content in fuels to limit emissions and meet increasingly stringent environmental standards.
Diesel market and fuel price fluctuations
Like gasoline, diesel prices are directly influenced by the global energy market. Factors such as crude oil supply, transportation demand, production policies of oil-exporting countries, and geopolitical tensions can all impact fuel prices.
Recently, the global oil market has remained volatile. According to forecasts by the International Energy Agency, oil supply is expected to increase in 2026 as several countries expand their production. However, fuel demand for transportation and industry remains high, especially in developing economies.
These factors cause oil prices in general, including diesel, to fluctuate frequently. In Vietnam, retail gasoline and diesel prices are adjusted periodically based on developments in the world market, so the operating costs of many transportation or construction businesses are also directly affected by these fluctuations.
A note on operating diesel-powered equipment
For equipment using diesel engines, such as generators or construction machinery, monitoring operating conditions is crucial. If the equipment is overloaded or the electrical system is unstable, the engine may consume more fuel and have a shorter lifespan.
In practice, many companies perform quick voltage or temperature checks on equipment before operation to detect early signs of abnormalities using devices such as handheld multimeters or infrared thermometers, which are quite common in everyday life due to their versatility.
Although the world is gradually shifting towards cleaner energy sources, diesel fuel still plays a crucial role in many sectors, especially transportation and heavy industry. Thanks to its good fuel efficiency, high load capacity, and engine durability, diesel remains a suitable choice for many systems requiring stable operation over long periods.
