Katerina Swanson
The density of diesel fuel is a critical factor in determining its quality and performance. Diesel fuel, designed specifically for diesel engines, is a liquid fuel that powers combustion engines in self-powered rail vehicles, like locomotives and railcars. The density of diesel fuel is defined as the mass of unit volume at a selected temperature, and it plays a significant role in engine calibration, power, and emissions. Variations in diesel density impact the fuel-air mixture, torque, and energy content, influencing the overall efficiency of the engine. The integrity and longevity of diesel fuel are closely tied to its density, making it an essential consideration for optimal engine performance and fuel economy.
Explore related products
$64.25 $82.67
What You'll Learn
Diesel density vs. petrol density
Diesel fuel, also known as diesel oil, heavy oil, or simply diesel, is a liquid fuel specifically designed for use in a diesel engine. This is a type of internal combustion engine where fuel ignition occurs without a spark due to the compression of inlet air and the subsequent injection of fuel. The most common type of diesel fuel is a specific fractional distillate of petroleum fuel oil. However, alternatives that are not derived from petroleum, such as biodiesel, biomass-to-liquid (BTL), or gas-to-liquid (GTL) diesel, are becoming increasingly popular.
Petrol, on the other hand, is made from a mix of alkanes and cycloalkanes with carbon atom chain lengths ranging from 5 to 12. These have lower boiling points compared to diesel, ranging from 40°C to 205°C. After distillation, various techniques are employed to convert fractions, including cracking, unification, and alteration, to create petrol fuel.
The density of diesel fuel is about 0.820 to 0.85 kg/l, which is approximately 9.0-15% higher than petrol, which has a density of around 0.70-0.775 kg/l. This higher density in diesel results in a higher volumetric energy density, meaning it contains about 15% more energy by volume. For example, EN 590 diesel fuel has a density of 0.820 to 0.845 kg/L at 15 °C, while EN 228 gasoline (petrol) has a density of 0.720-0.775 kg/L at the same temperature.
Due to its higher density, diesel fuel offers better fuel economy compared to petrol. The calorific value of diesel is slightly lower than petrol, with diesel at 45.5 MJ/kg and petrol at 45.8 MJ/kg. However, the overall efficiency of a diesel engine is about 20% greater than a petrol engine, even though diesel engines are heavier. Additionally, diesel fuel tends to be safer than petrol due to its higher flash point, which ranges from 52°C to 96°C.
Galvanized Pipes: Safe for Diesel Fuel?
You may want to see also
Explore related products
The impact of sulfur content
The density of diesel fuel is about 0.85 kg/l, which is 15-20% higher than the density of gasoline, which has a density of approximately 0.70-0.75 kg/l. The density of EN 590 diesel fuel is defined as 0.820 to 0.845 kg/L at 15 °C.
Diesel fuel contains sulfur, which is derived from the original crude oil source and can remain after refining. The combustion of sulfur in diesel fuel creates sulfuric acid, which causes corrosive wear on the metal surfaces of an engine. Sulfuric acids are the most significant corrosive acids when high-sulfur fuel is used.
To combat the corrosive effects of sulfur, engine oils with basic (alkaline) additives are used to react with sulfur acids, preventing them from reaching and corroding the metal surfaces of the engine. Detergent additives in engine oil also help neutralize corrosive acids and form non-corrosive by-products. Antioxidants are another additive used to prevent the formation of organic acids by blocking the oxidation process, thereby extending the life of the engine oil.
Regulations to reduce vehicle emissions have led to a dramatic decrease in allowable sulfur content in diesel fuel. As a result, modern engine oils no longer require high levels of detergents, and protection against organic acid corrosion has become a more necessary requirement.
Studies have shown that adding biodiesel to high-sulfur diesel can lead to reductions in pollutant emissions, with more significant reductions observed with increasing methyl ester portions in the fuel blend. Additionally, the use of gasoline-diesel blends can help reduce sulfur content, improve engine performance, and decrease exhaust emissions.
Overall, the impact of sulfur content in diesel fuel has driven the development of engine oil formulations with specific additives to protect against corrosion and improve engine performance. The reduction in sulfur content has also led to changes in engine oil requirements, with a focus on preventing organic acid corrosion.
The Impact of Diesel Fuel on Gas Engines
You may want to see also
Explore related products
Cetane number and ignition quality
The density of diesel fuel is about 0.85 kg/l, which is about 15–20% higher than the density of gasoline. Diesel fuel has a higher volumetric energy density than gasoline, which is an important factor in determining the quality of diesel fuel.
The cetane number is a measure of the tendency of diesel fuel to knock in a diesel engine. It is an important factor in determining the quality of diesel fuel, but not the only one. The cetane number is derived from the ignition delay time, which is the time between the start of injection and the start of combustion. A higher cetane number indicates a shorter ignition delay time, which results in more complete fuel combustion. This leads to quicker starting for vehicles, a quieter engine, improved fuel efficiency, and reduced harmful emissions.
The cetane number is calculated using a test developed in the 1930s by the Cooperative Fuel Research (CFR) Committee and later standardized as ASTM D613. The test involves running the fuel in a single cylinder, continuously variable compression ratio CFR Cetane Engine. Two primary reference fuels (hydrocarbons) define the cetane number scale: n-hexadecane (also known as cetane, with a cetane number of 100) and 2,2,4,4,6,8,8-heptamethylnonane (isocetane, with a cetane number of 15). When a fuel has the same ignition delay period as a mixture of these two reference fuels, its cetane number is derived from the volume percentage of cetane and heptamethylnonane.
The cetane index is another method to determine ignition quality, calculated from other fuel properties such as density and volatility. It provides a measure of fuel ignition quality without the need for costly testing.
Diesel Fuel: Highly Combustible and Dangerous?
You may want to see also
Explore related products
![[OEM Quality] Smoke Fluid Solution for Automotive Leak Detection – 800+ Uses, Works with All Smoke Machines for EVAP, Vacuum, Fuel, Intake, Exhaust, Turbo & Superchargers, High-Density - 16oz](https://m.media-amazon.com/images/I/718RD-8HVZL._AC_UY218_.jpg)
Fuel economy and energy density
The density of diesel fuel is a key factor in its energy efficiency and economy. Diesel fuel has a higher density than gasoline, typically ranging from 0.820 to 0.85 kg/l, compared to gasoline's density of approximately 0.70-0.775 kg/l. This higher density translates to greater volumetric energy density, resulting in superior fuel economy and range for vehicles.
The energy density of diesel fuel is notably higher than that of conventional petrol. While diesel has a density of around 836 kg/m3, conventional petrol averages 744 kg/m3, representing an 11% difference. This disparity in density leads to diesel engines achieving 25 to 35% better fuel economy than their petrol counterparts.
The composition of diesel fuel contributes to its high energy density. Diesel primarily consists of large, long-chain hydrocarbons, which impart a high energy content due to their size and length. This high energy density, combined with diesel engines' higher low-end torque, enables diesel vehicles to cover longer distances than comparable petrol vehicles.
The benefits of diesel's high energy density extend beyond fuel economy. Diesel fuel's ability to deliver superior tractive effort makes it ideal for applications requiring high torque and power, such as heavy trucks and machinery. Additionally, diesel engines' ability to auto-ignite makes them suitable for various non-diesel engines, including the Akroyd engine, Stirling engine, and boilers for steam engines.
However, it is important to consider the environmental implications of diesel fuel. While diesel engines produce slightly lower CO2 emissions per unit of energy compared to gasoline, diesel exhaust, especially from older engines, can have detrimental health effects. To mitigate this, ultra-low-sulfur diesel (ULSD) has been introduced, significantly reducing sulfur content and improving emissions. As of 2016, ULSD is the predominant type of diesel fuel in the United Kingdom, mainland Europe, and North America.
Adjusting the Fuel Governor on a 353 Detroit Diesel Engine
You may want to see also
Explore related products
The role of distillation
Diesel fuel is a liquid fuel designed for use in diesel engines, which are a type of internal combustion engine. Diesel fuel is a fractional distillate of petroleum fuel oil, though alternative types of diesel are being developed that are not derived from petroleum, such as biodiesel, biomass-to-liquid (BTL), or gas-to-liquid (GTL) diesel.
The process of fractional distillation involves heating crude oil to vapourise it and feeding it into the bottom of a distillation tower. As the resulting vapour rises through the vertical column, the temperature decreases, causing certain hydrocarbons to condense and run off at different levels. Each fraction that condenses off contains hydrocarbon molecules with a similar number of carbon atoms. This process is used to separate several hydrocarbons in a single operation. The fractions with boiling points of 70-200°C are considered light distillates and include gasoline, naphtha, kerosene, jet fuel, and paraffin. Diesel fuel is considered a medium distillate, with a boiling point of 200-350°C. Heavy distillates have boiling points above 350°C and include fuel oil.
Distillation plays a crucial role in the quality control of automotive fuels. The distillation curves of diesel and petrol are studied to understand their characteristics and behaviour in engines. The volatility of diesel fuel, in particular, influences engine performance. Low volatility leads to high distillation endpoints, resulting in high combustion times and poor combustion of heavy hydrocarbons. This, in turn, causes smoke formation, power loss, and increased fuel consumption. On the other hand, high volatility can cause "vapour lock" in the fuel lines. To prevent these issues, distillation is used to ensure that diesel fuel has the optimal volatility for efficient engine performance.
In terms of specific distillation temperatures, No. 1-D diesel fuel has a maximum recovery threshold of 90% vol at 288°C. No. 2-D diesel fuel has a slightly broader range, with a maximum threshold of 338°C and a minimum threshold of 282°C at 90% vol recovery. No. 2 diesel fuel, which can be used in high-speed diesel engines, has a distillation temperature of 640 degrees Fahrenheit (337.7°C) at the 90% recovery point.
Enhancing Diesel Fuel Performance: Additives or Not?
You may want to see also
Frequently asked questions
The density of diesel fuel is about 0.832 kg/L (6.943 lb/US gal) as of 2019. This can also be expressed as 838 g per liter.
Fuel density affects engine calibration and power as the mass injected per stroke varies with diesel density. It also impacts the engine combustion and emissions timings.
When the fuel density is less, the fuel mass will also be less for the same volume. This affects the stoichiometric ratio and the fuel-air mixture, which can reduce the efficiency of the diesel engine.
Diesel fuel has a higher density than gasoline (petrol), which is about 9.0-13.9% higher. This results in a higher volumetric energy density for diesel fuel.
The cetane number is a measure of the ignition quality of diesel fuel. A high cetane number indicates a fuel that auto-ignites readily and has a short ignition delay period, which is desirable for diesel engines.
