SCR | Selective Catalytic Reduction System

New in the Easy2Fit Program

SCR systems are a further step in the pollution control of diesel vehicles. They were introduced with the Euro 6 standard in 2014 to reduce NOx. Faurecia now offers SCR systems as part of its Easy2Fit® range, with a competitive offer adapted to the independent aftermarket.

Definition of NOx

Nitrogen oxides, or NOx, are pollutants emitted by diesel engines that can cause serious damage to our health, such as respiratory diseases. They are also responsible for smog and the typical brown cloud that covers large cities and ensures poor air quality. SCR systems are used to reduce NOx emissions from diesel vehicles. It is therefore essential to ensure that they are working properly and, if necessary, to replace them with a quality system.

Euro Standards

Euro standards are European Union directives whose main objective is to limit the polluting emissions of different types of vehicles. These standards set maximum emissions of the following gases: nitrogen oxides (NOx), total hydrocarbons (THC), non-methane hydrocarbons (NMHC), carbon monoxide (CO) and fine particles (PM). The emergence and development of these directives has led to the introduction of new components in exhaust systems, such as catalysts, diesel and petrol particulate filters and, more recently, SCR.

The table below shows the Euro standards for light duty diesel and petrol vehicles.


Euro StandardsDateCO g/kgHC+NOxNOx g/kmPMPN #/km
Euro 1July 19922.72 (3.16)0.97 (1.13)0.14 (0.18)
Euro 2January 19961.00.50.08
Euro 3January 20000.660.560.500.05
Euro 4January 20050.500.300.250.025
Euro 5September 20090.500.2300.180.0056×1011
Euro 6September 20140.500.1700.080.00456×1011


Euro StandardsDateCO g/kgHC+NOxNOx g/kmPMPN #/km
Euro 1July 19922.72 (3.16)0.97 (1.13)
Euro 2January 19962.20.5
Euro 3January 20002.30.15
Euro 4January 20051.00.08
Euro 5September 20091.00.0600.005
Euro 6September 20141.00.0600.00456×1011

Over the years, Euro standards have become stricter in order to protect our health and the environment. It is indeed essential to reduce vehicle emissions as much as possible. At Faurecia, our core business is to help automakers develop solutions for clean mobility. We apply this expertise to the aftermarket with our Easy2Fit offering, which enables motorists to acquire high-quality products that are 100% compliant with current European standards.

Main components of SCR systems

  • DOC |  Diesel Oxidation Catalyst
  • SCR | Selective Catalytic Reduction System (with urea injector)
  • DPF | Diesel Particulate Filter (silicon carbide or cordierite)

How does a SCR system work?

SCRs are catalytic systems that reduce nitrogen oxide emissions (NOx) by converting them into harmless gases through a chemical reaction.  To achieve this, a liquid additive consisting of urea and demineralized water is injected into the catalytic system. This agent is introduced into the exhaust system upstream of the SCR. The fluid is distributed evenly over the surface of the SCR by means of a component of the pollution control system called a “mixer”. The SCR together with the urea fluid allows the transformation of harmful gases into harmless gases, N2 and H2O. 

Faurecia Easy2Fit® differentiators

  • The quality of the materials used, bricks and precious metals, in our systems allow for optimal NOx treatment.
  • Our expertise as a leader in the exhaust market has earned us the trust of original equipment manufacturers and major aftermarket players.
  • The quality and durability of our products is our primary concern, for a cleaner environment, for the well-being of all.
  • Like all Easy2Fit systems, our SCRs are sold with the corresponding mounting accessories.