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SCR System

Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system used in diesel engines.

What is Selective Catalytic Reduction?

Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system that injects a liquid-reductant agent through a special catalyst into the exhaust stream of a diesel engine. The reductant source is usually automotive-grade urea, otherwise known as Diesel Exhaust Fluid (DEF). The DEF sets off a chemical reaction that converts nitrogen oxides into nitrogen, water, and tiny amounts of carbon dioxide (CO2), natural components of the air we breathe, which is then expelled through the vehicle tailpipe.

SCR technology is designed to permit nitrogen oxide (NOx) reduction reactions to take place in an oxidizing atmosphere. It is called “selective” because it reduces levels of NOx 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 tiny amounts of CO2. The DEF can be rapidly broken down to produce the oxidizing ammonia in the exhaust stream. SCR technology alone can achieve NOx reductions up to 90 percent.

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Why is SCR important?

SCR technology is one of the most cost-effective and fuel-efficient technologies available to help reduce diesel engine emissions. All heavy-duty diesel truck engines produced after January 1, 2010, must meet the latest EPA emissions standards, among the most stringent in the world, reducing particulate matter (PM) and nitrogen oxides (NOx) to near-zero levels. SCR can reduce NOx emissions up to 90 percent while simultaneously reducing HC and CO emissions by 50-90 percent and PM emissions by 30-50 percent. SCR systems can also be combined with a diesel particulate filter to achieve even greater emission reductions for PM. In the commercial trucking industry, some SCR-equipped truck operators are reporting fuel economy gains of 3-4 percent. Additionally, off-road equipment, including construction and agricultural equipment, must meet EPA’s Tier 4 emissions standards requiring similar reductions in NOx, PM, and other pollutants. SCR is one technology that can help off-road equipment meet these stringent emissions standards.

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Where is SCR used?

SCR has been used for decades to reduce stationary source emissions. In addition, marine vessels worldwide have been equipped with SCR technology, including cargo vessels, ferries and tugboats. With its superior return in both economic and environmental benefits, SCR is also being recognized as the emissions control technology particularly helpful in meeting the U.S. EPA 2010 diesel engine emission standards for heavy-duty vehicles, and the Tier 4 emissions standard for engines found in off-road equipment. SCR systems are also found in the growing number of diesel passenger vehicles.

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What is the Future for SCR Technology?

The U.S. Environmental Protection Agency (EPA) announced efforts to develop more stringent tailpipe emission standards for commercial vehicles close to zero through the “Cleaner Trucks Initiative”. Refinements and improvements to SCR systems will be critical technology to deliver closer-to-zero emissions. Dosing events, compact designs and placement of SCR systems integrated into commercial vehicles will play an important role in reducing emissions.

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In order to reduce the emission of harmful gases in automobile exhaust, SCR (Selective Catalytic Reduction) exhaust treatment technology is widely used internationally.

The principle of the SCR system is to use an AdBlue aqueous solution for vehicles to react with nitrogen oxides (NOx) to generate pollution-free nitrogen (N2), and water (H2O).

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Our factory management is in accordance with international 5S standards, strict requirements and supervision of the various production processes.

1. ISO9001 quality system certified.
2.Good material&Advanced technology& strict quality control ensure high quality; High quality makes sure long usage life.
3.Quick delivery 3-7 days.
4.Competitive price.
5.Various types, and different car models.


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