Regan Brown
Diesel exhaust fluid (DEF) is a non-toxic, colourless liquid that reduces harmful emissions from diesel engines. It is composed of 32.5% urea and 67.5% deionized water. DEF is stored separately from diesel fuel and injected into the exhaust stream, where it breaks down into ammonia and carbon dioxide. This mixture then reacts with nitrogen oxide in the exhaust, converting it into harmless nitrogen, water, and a small amount of carbon dioxide. DEF is essential for diesel vehicles to meet federal emissions standards and improve fuel efficiency.
| Characteristics | Values |
|---|---|
| Full form | Diesel Exhaust Fluid |
| Other names | DEF, AUS 32, AdBlue |
| Composition | 32.5% urea, 67.5% deionized water |
| Function | Reduces harmful emissions from diesel engines, specifically nitrogen oxides (NOx) |
| Use | Injected into the exhaust stream of a diesel engine |
| Effect | Converts harmful gases into harmless nitrogen, water, and a little carbon dioxide |
| Injection rate | 2-6% of diesel consumption volume |
| Weight | 1 gallon = 4.1 kilograms |
| Freezing point | 11 F |
| Tank | Stored separately in its own tank on diesel vehicles |
Explore related products
What You'll Learn
DEF is a non-toxic, colourless liquid
DEF, or Diesel Exhaust Fluid, is a non-toxic, colourless liquid that is essential for reducing harmful emissions in diesel engines. It is a mix of deionized water and urea, with 67.5% of the former and 32.5% of the latter. This liquid is not to be confused with diesel fuel and is stored separately in its own tank.
The primary function of DEF is to reduce harmful nitrogen oxide emissions from diesel engines and convert them into safe water and nitrogen. DEF is consumed in a selective catalytic reduction (SCR) that lowers the concentration of nitrogen oxides in diesel exhaust emissions. DEF is injected into the hot exhaust gas stream, where the water evaporates and the urea decomposes to form ammonia and isocyanic acid. The ammonia then reacts with the nitrogen oxides in the exhaust, converting them into harmless nitrogen and water vapour. This process helps to significantly reduce the amount of nitrogen oxide released into the air, making it safer for people to breathe and less harmful to the environment.
DEF is crucial for diesel-powered vehicles and heavy equipment, and almost every diesel-powered engine in the United States relies on it. It helps these vehicles meet strict environmental regulations without compromising engine performance. By using DEF, manufacturers can keep diesel engines efficient and powerful while reducing their environmental impact. DEF also improves fuel efficiency, leading to better fuel economy and a modest improvement in overall engine performance.
The amount of DEF used depends on the engine and tank size of the vehicle. It is typically injected at a low dose of 2-6% of diesel consumption volume, ensuring long fluid refill intervals and minimizing tank size. DEF is available in various sizes, from individual containers to bulk supply options, making it accessible for different needs.
Eradicating Algae Bloom in Diesel: Hot Water Treatment
You may want to see also
Explore related products
DEF is made from 32.5% urea and 67.5% deionized water
Diesel exhaust fluid (DEF) is a mixture of 32.5% urea and 67.5% deionized water. It is used in selective catalytic reduction (SCR) systems to reduce nitrogen oxide (NOx) emissions from diesel engines.
The SCR system injects DEF into the exhaust stream, where it reacts with NOx in the presence of a catalyst. This process converts harmful NOx into harmless nitrogen and water vapour, which are then released into the atmosphere through the exhaust. DEF also helps to improve the fuel efficiency of diesel vehicles by around 3-4%.
The urea used in DEF is considered the first organic compound to be synthesized from inorganic chemicals. It can be safely stored at room temperature and pressure, and has low reactivity and a slow evaporation rate. Urea is also non-toxic, and is used in other applications such as fertiliser, animal feed, and cosmetic products.
The injection rate of DEF into the exhaust depends on the specific after-treatment system, typically ranging from 2-6% of diesel consumption volume. This low dosing rate ensures long fluid refill intervals and minimises the size of the DEF tank required.
DEF is essential for diesel vehicles to meet federal emissions standards. Without DEF, diesel vehicles would emit high levels of nitrogen oxide, which can irritate the eyes, nose, throat, and lungs, and cause other health issues.
Idle Diesel Engines: How Much Fuel Do They Consume?
You may want to see also
Explore related products
DEF is stored separately in its own tank
Diesel Exhaust Fluid (DEF) is a non-toxic, non-flammable, and biodegradable liquid that is essential for reducing harmful emissions in diesel engines. It is a mix of deionized water and urea, which helps convert nitrogen oxide emissions from diesel engines into safe water and nitrogen. DEF is not a fuel in the conventional sense and is not mixed with diesel fuel. Instead, DEF is stored separately in its own tank on diesel vehicles equipped with Selective Catalytic Reduction (SCR) systems.
The SCR system mixes urea (DEF) and diesel exhaust over a catalyst bed inside the exhaust system, which reduces nitrogen oxide emissions. DEF is injected into the hot exhaust gas stream, where the water evaporates and the urea decomposes to form ammonia and isocyanic acid. The ammonia then reacts with the nitrogen oxides in the exhaust inside the SCR catalyst, converting them into harmless nitrogen and water vapour.
DEF is typically stored in a dedicated tank, often marked with a blue cap, to avoid confusion with diesel fuel. The blue cap helps prevent inadvertent contamination of both diesel and DEF in tanks. The injection rate of DEF into the exhaust depends on the specific after-treatment system but is usually around 2-6% of diesel consumption volume. This low dosing rate ensures long fluid refill intervals and minimises the tank's size.
DEF is available in various sizes, from individual containers to bulk supply options. It is important to store DEF properly to avoid contamination, which could affect the engine's performance. DEF also has a freezing point of 11 degrees Fahrenheit, and when it freezes, its volume can expand by up to 7%. Therefore, it is recommended to leave enough room in the tank for thermal expansion to prevent cracking.
Overall, the separate storage of DEF in its own tank is crucial for the proper functioning of the SCR system and for ensuring compliance with environmental and emissions regulations.
The Ultimate Diesel Fuel Supplement Guide
You may want to see also
Explore related products
DEF improves fuel efficiency by 3-4%
Diesel Exhaust Fluid (DEF) is a mixture of 32.5% urea and 67.5% de-ionized water. It is used to reduce harmful emissions from diesel engines, specifically nitrogen oxide (NOx) emissions. DEF is consumed in a selective catalytic reduction (SCR) system, which lowers the concentration of NOx in diesel exhaust emissions.
The SCR system, employed by most trucks, ensures the engine operates efficiently while emitting cleaner substances. The system injects DEF through a catalyst, and it then travels into the vehicle's exhaust stream. Here, the urea in the DEF reacts with the nitrogen oxide, converting it into harmless nitrogen, water, and a small amount of carbon dioxide. This process not only reduces harmful emissions but also enhances engine performance and fuel efficiency.
The use of DEF is essential for diesel engines to comply with federal emissions standards. Without DEF, diesel vehicles would emit high levels of nitrogen oxide, which can irritate the eyes, nose, throat, and lungs. By utilising DEF, vehicles can adhere to environmental regulations while also contributing to environmental preservation.
Diesel Engines: Dual Fuel Pumps for Efficiency and Power
You may want to see also
Explore related products
DEF is essential for reducing harmful emissions
Diesel Exhaust Fluid (DEF) is a non-toxic, colourless liquid that is essential for reducing harmful emissions from diesel engines. It is composed of 32.5% high-purity urea and 67.5% deionized water. DEF is not a fuel in the conventional sense and is not mixed with diesel fuel. Instead, it is stored separately in its own tank on diesel vehicles equipped with Selective Catalytic Reduction (SCR) systems.
The primary function of DEF is to reduce harmful nitrogen oxide (NOx) emissions from diesel engines. These emissions are a significant contributor to air pollution and smog and can irritate the eyes, nose, throat, and lungs. DEF helps convert these harmful gases into harmless nitrogen, water, and a small amount of carbon dioxide, which are much safer for people to breathe and less harmful to the environment.
DEF is consumed in the SCR process, which lowers the concentration of NOx in diesel exhaust emissions. The SCR system mixes DEF and diesel exhaust over a catalyst bed inside the exhaust system, reducing NOx emissions. DEF is injected into the hot exhaust gas stream, where the water evaporates and the urea decomposes to form ammonia and isocyanic acid. The ammonia then reacts with the NOx in the exhaust, converting it into harmless nitrogen and water vapour.
The use of DEF is essential for diesel vehicles to meet strict environmental regulations and federal emissions standards set by organisations like the Environmental Protection Agency (EPA). Without DEF, diesel vehicles would violate these standards and emit high levels of harmful NOx into the atmosphere. DEF also offers additional benefits, such as improved fuel efficiency, longer engine life, and better engine performance.
The amount of DEF used can vary depending on the vehicle's engine and tank size, and it is important to ensure that high-quality, uncontaminated DEF is used for optimal performance. DEF is available at many truck stops and fuel stations, making it convenient for drivers to refill their DEF reservoirs regularly. Overall, DEF plays a crucial role in reducing harmful emissions from diesel engines and contributing to a cleaner, safer environment.
Diesel Engines: Multiple Fuel Filters, Why?
You may want to see also
Frequently asked questions
DEF, short for Diesel Exhaust Fluid, is a non-toxic, colourless liquid made from a precise mixture of 32.5% high-purity urea and 67.5% deionized water. It is stored separately from diesel fuel and injected into the exhaust stream of a diesel engine to reduce harmful emissions.
DEF helps to convert harmful nitrogen oxide emissions from diesel engines into safe water and nitrogen. It also improves fuel efficiency, resulting in a modest improvement in fuel economy for motorists.
DEF is necessary to ensure diesel engines comply with federal emissions standards. Without DEF, diesel vehicles would violate the standards set by the EPA and other environmental regulations.
