What You Need to Know About Diesel Fuel

Diesel fuel, also known as diesel oil, is a type of liquid fuel. Its ignition is done without the use of a spark. Instead, it happens due to the compression of the air in the engine and the injection of fuel. When you’re in the market for a new car, diesel might be an option worth considering.

Cetane number

Unlike gasoline, diesel fuel contains a high amount of aromatics, with fewer amounts of alkanes, alkenes, and naphthenes. As a result, there are strict emission control regulations governing the diesel fuel market. To ensure that vehicles meet those standards, government authorities have set minimum cetane numbers for diesel fuel. The cetane number of diesel fuel is affected by several factors, including the size and design of the engine, load variations, and engine starting conditions. A lower cetane number can result in a poorer running engine, vibrations, extra noise, and increased engine wear.

Various tests and special procedures are used to measure cetane numbers. Testing diesel under varying conditions is time consuming and expensive. Therefore, a calculated method is used instead. This method incorporates a number of different tests, including the ASTM D976 and ASTM 4737.

Hydrocarbon composition

The hydrocarbon composition of diesel fuel is one of the most important factors that influence its properties. Hydrocarbon group composition is reflected by the ratio of the carbon to hydrogen. It can be measured in various ways, including chromatography. A detailed study of the hydrocarbon composition can reveal the impact of different hydrocarbon groups on individual fuel characteristics.

Diesel fuels containing large hydrocarbon molecules produce less energy than those containing smaller hydrocarbon molecules. This is due to the combustion technology of the engine. Nevertheless, this incomplete combustion generates toxic chemical compounds, which are very harmful for the environment. Hydrocarbons that undergo complete combustion release carbon dioxide and water, which are among the top ten greenhouse gases.

Combustion process

The diesel combustion process involves a series of processes that are controlled by the engine’s fuel injection and pressure. The first stage is known as rapid ignition and is marked by a sharp increase in cylinder pressure. This increases the amount of oxygen available for combustion, which decreases the time between premixed combustion and ignition. However, it also increases the amount of soot produced, and is accompanied by a decrease in the in-cylinder temperature.

The heat involved in the combustion process of diesel fuel is high, and is largely exothermic. This means that the energy in the fuel is released as heat and light. The reaction’s enthalpy changes in the process, leaving the reactants with less energy than they were when the fuel was initially injected. To calculate the change in enthalpy, you can use an online calculator.

Pollution produced

Diesel emission produces a variety of pollutants that may affect the health of drivers and the environment. These pollutants are produced from non-ideal combustion processes, including incomplete combustion of fuel, reactions between mixture components at high temperatures, and the combustion of engine lubricating oil and other oil additives. Diesel exhaust gases typically contain sulfur compounds, nitrogen oxides, and particulate matter.

Diesel engine particulate matter emissions are six to ten times higher than emissions from gasoline engines. These particulate emissions are divided into three parts: soot, the soluble organic fraction, and the inorganic fraction. The soot component makes up the largest portion of the diesel PM emissions. The soluble organic fraction contains heavy hydrocarbons that are produced in the combustion process. Despite being low in exhaust temperature, the soluble organic fraction still produces a large proportion of PM emissions.

Alternative fuels

There are a variety of alternative fuels for diesel engines. However, the disadvantages of using these fuels are high emissions, high heat release rate, and high combustion temperature. Additionally, waste lubricating oil, which is a poor substitute for diesel, contributes to incomplete combustion and can increase PM and HC. However, proper fuel management can reduce emissions and improve the efficiency of alternative fuels.

Alcohol fuel, for example, is a type of alternative fuel for diesel engines. Alcohol fuel is usually mixed with biodiesel, which is made from waste oil. This type of fuel also has a high calorific value, but cannot be used directly in diesel engines. Rather, it is mixed with other fuels for maximum combustion efficiency and lowest NOX emissions.

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