Ameer Randolph
Selective Catalytic Reduction (SCR) is an exhaust system emissions control technology that converts nitrogen oxides (NOx) into nitrogen, water, and carbon dioxide (CO2). SCR technology is designed to allow nitrogen oxide (NOx) reduction reactions to occur in an oxidizing atmosphere. SCR can reduce NOx emissions by up to 90% while also reducing HC and CO emissions by 50-90% and PM emissions by 30-50%cost-effective and fuel-efficient methods for lowering diesel engine emissions. SCR systems are now the preferred method for meeting Tier 4 Final and EURO 6 diesel emissions standards for heavy trucks, cars, and light commercial vehicles.
| Characteristics | Values |
|---|---|
| What is SCR? | Selective Catalytic Reduction |
| What is DEF? | Diesel Exhaust Fluid |
| What does SCR do? | Converts nitrogen oxides into nitrogen, water, and carbon dioxide |
| How does SCR work? | Uses ammonia as a reductant within a catalyst system |
| What is DEF made of? | Purified water and automotive-grade aqueous urea |
| How much does SCR cost? | SCR catalysts can cost upwards of $1,000 plus labor |
| What are the benefits of SCR? | Can reduce NOx emissions by up to 90% while reducing HC and CO emissions by 50-90% and PM emissions by 30-50% |
| What are the drawbacks of SCR? | Requires additional maintenance and repair, and the DEF tank must be refilled periodically |
| Where can I buy DEF? | Available at service stations, convenience stores, automotive parts stores, truck stops, truck dealerships, and engine distributors |
Explore related products
$87.48 $99.96
What You'll Learn
- SCR technology converts nitrogen oxide into nitrogen, water, and carbon dioxide
- SCR can reduce NOx emissions by up to 90%
- SCR systems can be combined with diesel particulate filters to achieve greater emission reductions
- SCR technology is cost-effective and fuel-efficient
- SCR catalysts can cost upwards of $1000 plus labour
SCR technology converts nitrogen oxide into nitrogen, water, and carbon dioxide
Selective Catalytic Reduction (SCR) is an active emissions control system that converts nitrogen oxide into nitrogen, water, and carbon dioxide. Hot exhaust gases flow out of the engine and into the SCR system, where aqueous urea (known as Diesel Exhaust Fluid or DEF) is sprayed onto a special catalyst. The DEF sets off a chemical reaction in the exhaust that converts nitrogen oxides into nitrogen, water, and tiny amounts of carbon dioxide (CO2).
The design of SCR technology permits nitrogen oxide (NOx) reduction reactions to take place in an oxidizing atmosphere. It is called "selective" because it reduces NOx levels using ammonia as a reductant within a catalyst system. The chemical reaction is known as "reduction", where the DEF is the reducing agent that reacts with NOx to convert the pollutants into nitrogen, water, and CO2. DEF is rapidly broken down to produce the oxidizing ammonia in the exhaust stream.
SCR technology is one of the most cost-effective and fuel-efficient technologies available for reducing diesel engine emissions. SCR can reduce NOx emissions by up to 90% while simultaneously reducing HC and CO emissions by 50-90% and PM emissions by 30-50%. SCR systems can also be combined with a diesel particulate filter to achieve even greater emission reductions for PM.
The largest sector for the use of SCR technology in the US is heavy-duty commercial trucks. All heavy-duty diesel truck engines produced after January 1, 2010, must meet the latest EPA emissions standards, which are among the most stringent in the world. SCR technology is now the preferred method for meeting Tier 4 Final and EURO 6 diesel emissions standards for heavy trucks, cars, and light commercial vehicles.
Cleaning Old Diesel Fuel: The Ultimate Guide
You may want to see also
Explore related products
SCR can reduce NOx emissions by up to 90%
Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system that reduces tailpipe emissions of nitrogen oxides (NOx) in newer-generation diesel-powered vehicles and equipment. SCR technology can achieve up to 90% NOx reduction, and it has been used extensively in commercial on- and off-road vehicles. SCR is highly effective at treating engine-out exhaust, allowing manufacturers to balance engine performance and maximise fuel economy.
The SCR system involves several components packaged together with other parts of the emissions control system. Each manufacturer has its own variations of the type and sequencing of different components in the system. The SCR system works by injecting automotive-grade urea, or Diesel Exhaust Fluid (DEF), through a specially designed catalyst, into the exhaust stream of a diesel engine. The DEF sets off a chemical reaction in the exhaust on a special catalyst that converts nitrogen oxides into nitrogen, water, and tiny amounts of carbon dioxide (CO2). The DEF is rapidly broken down to produce the oxidising ammonia in the exhaust stream.
SCR technology is one of the most cost-effective and fuel-efficient technologies available to help reduce diesel engine emissions. DEF refill intervals for light-duty vehicles typically occur around the time of a recommended oil change, while DEF replenishment for heavy-duty vehicles and off-road machines and equipment will vary depending on operating conditions, hours used, miles travelled, load factors, and other considerations. DEF is an integral part of the emissions control system and must be present in the tank at all times to assure the continued operation of the vehicle or equipment.
SCR systems can also be combined with a diesel particulate filter to achieve even greater emission reductions. The high efficiency of SCR systems in reducing NOx emissions allows manufacturers to balance engine performance and maximise fuel economy, while still achieving near-zero emissions. Some SCR-equipped heavy-duty commercial truck operators report fuel economy gains of more than 4%.
Diesel Fuel Degradation: How Long Does It Last?
You may want to see also
Explore related products
SCR systems can be combined with diesel particulate filters to achieve greater emission reductions
Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system that reduces tailpipe emissions of nitrogen oxides. It is called "selective" because it reduces levels of nitrogen oxide (NOx) using ammonia as a reductant within a catalyst system. The chemical reaction, known as "reduction", involves a reducing agent reacting with NOx to convert pollutants into nitrogen, water, and small amounts of carbon dioxide (CO2). SCR technology is highly effective, reducing NOx emissions by up to 90% and HC and CO emissions by 50-90%, with PM emissions being reduced by 30-50%.
SCR systems can be combined with diesel particulate filters (DPF) to achieve even greater emission reductions, especially for PM. This combination is possible because the two systems address different types of emissions. While SCR treats gaseous emissions, DPF captures particulate matter by filtering out solid particles from the exhaust stream.
The DPF is designed to hold a certain amount of soot, but it can become loaded and clogged over time due to the high deposition of soot. This can lead to increased back pressure on the engine, affecting its performance. To prevent this, it is important to maintain a high enough average temperature so that the stored soot is converted to CO2, keeping the filter clean. Alternatively, an active regeneration system can be installed to periodically increase the filter temperature for faster regeneration.
The combination of SCR and DPF technologies allows for a more comprehensive approach to emission reduction, ensuring that both gaseous and particulate emissions are addressed effectively. This integration enables manufacturers to balance engine performance and maximize fuel economy while achieving near-zero emissions.
Off-Road Diesel Fuel: Farmers' Current Cost Concerns
You may want to see also
Explore related products
SCR technology is cost-effective and fuel-efficient
Selective Catalytic Reduction (SCR) is a cost-effective and fuel-efficient technology for diesel engines. It is an advanced active emissions control technology that reduces tailpipe emissions of nitrogen oxides (NOx) and other pollutants. SCR technology has been used for decades to reduce emissions from various industrial operations, and its effectiveness and efficiency make it a popular choice for engine manufacturers.
The SCR system involves injecting a liquid reductant agent, typically automotive-grade urea or Diesel Exhaust Fluid (DEF), into the exhaust stream of a diesel engine. This sets off a chemical reaction that converts nitrogen oxides into nitrogen, water, and small amounts of carbon dioxide (CO2). The SCR system allows for the reduction of NOx emissions by up to 90% while simultaneously reducing HC and CO emissions by 50-90% and PM emissions by 30-50%.
The high efficiency of SCR systems in reducing emissions allows manufacturers to balance engine performance and maximize fuel economy. SCR-equipped heavy-duty commercial truck operators have reported fuel economy gains of more than 4%. The SCR system is also flexible, working with various fuel qualities and types, and does not require ultra-low sulfur diesel. This makes it a user-friendly solution that is simple to maintain, with the only requirement being the regular refilling of DEF.
The wide adoption of SCR technology has led to a nationwide DEF distribution infrastructure, making DEF readily available at retail stores, online, and at most fuelling stations. The price of DEF is expected to decrease due to the growing network of DEF supply. SCR technology is, therefore, a cost-effective and fuel-efficient solution for diesel engines, helping to reduce emissions and improve fuel economy.
Removing Emulsified Diesel Fuel: Effective Strategies
You may want to see also
Explore related products
SCR catalysts can cost upwards of $1000 plus labour
Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system that reduces tailpipe emissions of nitrogen oxides (NOx) and other pollutants. It is one of the most cost-effective and fuel-efficient technologies available to help reduce diesel engine emissions. SCR technology is highly effective, reducing NOx emissions by up to 90% and lowering HC, CO, and PM emissions by 30-50%.
While SCR technology offers significant environmental and economic benefits, the installation and maintenance of SCR systems come at a cost. The SCR catalyst itself can be expensive, often costing upwards of $1000, and this price does not include the labour costs associated with installation. The overall cost of SCR systems can vary depending on various factors, such as the type of ammonia system used, the size of the unit, and the specific design attributes.
The installation of SCR systems may involve construction labour, equipment, materials, and project management fees. Smaller projects tend to have higher construction labour costs relative to larger projects due to a lack of economies of scale. Additionally, the SCR catalyst has a finite operational lifetime, typically ranging from 1.8 to 9 years, depending on the application and gas composition. This means that replacement catalysts will need to be factored into the long-term costs of operating an SCR system.
The use of SCR technology also requires the periodic replenishment of Diesel Exhaust Fluid (DEF), which is an integral part of the emissions control system. DEF is readily available for purchase at various locations, including retail stores and fuelling stations, and its price is expected to decrease due to the growing network of DEF supply. While DEF consumption is typically around 3% of fuel consumption, it is crucial for the continued operation of the vehicle or equipment, and low-DEF supply triggers warning indicators.
Smaller Tires, Better Fuel Economy?
You may want to see also
Frequently asked questions
SCR stands for Selective Catalytic Reduction. It is an exhaust system emissions control technology that converts nitrogen oxide (NOx) into nitrogen, water, and carbon dioxide.
SCR technology uses a catalytic converter to oxidize and convert NOx into other elements. It is called "selective" because it reduces levels of NOx using ammonia as a reductant within a catalyst system.
SCR can reduce NOx emissions by up to 90% while simultaneously reducing HC and CO emissions by 50-90% and PM emissions by 30-50%. SCR systems can also be combined with a diesel particulate filter to achieve even greater emission reductions. SCR technology also allows for increased fuel efficiency.
