What is SCR

The S.K. SCR system


Under Selective catalytic reduction (English selective catalytic reduction = SCR) are diesel systems that reduce nitrogen oxides in the exhaust gas. In this case, (selective) NO, NO are preferred2 reduced while other responses are suppressed. With the help of this technology, commercial vehicles canEuro-5 or Euro 6 fulfill. An aqueous urea solution (AdBlue) is injected to set the chemical processes in motion. The Federal Motor Transport Authority (KBA) specifies the guidelines that must be adhered to for measuring exhaust gases.

The S.K. Handels GmbH ran an S.K. Diesel particulate combination filter on the market. In 2013 the development of the S.K. Euro 5 SCR systems and meanwhile the exhaust aftertreatment system is also available for Euro 6 vehicles.

What is an SCR system for hardware retrofitting for diesel?

An SCR system is used for exhaust aftertreatment through which a diesel vehicle can meet a low particulate reduction level and emissions standard without interfering with the engine control or electronics.

90% of the harmful nitrogen oxides in the exhaust gas are produced by continuously injecting a liquid reducing agent mostly (AdBlue) in the exhaust system in ammonia (NH3) and converted into steam and nitrogen by a catalyst. The temperature and pressure curve is recorded by sensors and fed into the control unit so that it is functioning properly.

Minimal intervention, great effect SK SCR technology in the vehicle

The SCR system for hardware retrofitting is integrated into the exhaust system with little intervention. The individual components can be mounted flexibly and freely placeable in the vehicle. The use of existing resources in the vehicle enables a high degree of adaptability for different vehicle models.


Retrofit components for SCR diesel retrofitting - Image: SK-Handels-GmbH

SCR system Euro 6 hardware retrofit Toyota HZJ

SK Handels GmbH brought a complex one in 2016Euro 6 SCR system for the Toyota HZJ on the market.

Since the enthusiast and cult vehicle could no longer be registered as a new registration on the European market due to the excessively high exhaust emissions, the research & development team developed an exhaust gas cleaning system so that the vehicle again meets the exhaust gas limit values ​​of the Euro 6 standard.

Thanks to the Euro 6 SCR system, the Toyota HZJ achieves Euro 6. - Image: SK-Handels-GmbH

Diesel particulate filters and catalysts

Through the partnership with HJS Emission Technology GmbH & Co. KG, S.K. Handels GmbH is able to offer particle filters for almost every vehicle. In response to individual customer inquiries, diesel particulate filters are also offered for truck, bus and commercial vehicles.


How the S.K. Euro 5 SCR system (selective catalytic reduction system)

The S.K. Handels GmbH

The S.K. The Euro 5 SCR system was purely an exhaust aftertreatment system that did not intervene in the engine control or vehicle electronics. By injecting the urea solution, a chemical reaction is triggered in the SCR filter, which converts NOx (nitrogen oxides) into non-toxic substances. In detail, ammonia and CO2 are produced by hydrolysis from the urea-water solution. In a further step, the ammonia in the SCR catalytic converter reacts with the nitrogen oxides at the appropriate temperature. The urea solution is injected into the exhaust system via an injection valve. This process reduces the pollutants to the limit values ​​required for Euro 5. The temperature and pressure curve are recorded by various sensors and probes so that the control unit can guarantee that it is functioning properly.

SK Handels GmbH (company)

Today's S.K. Handels GmbH, a medium-sized company with headquarters in Aicha vorm Wald near Passau, was founded in 1978 as a motor vehicle company with the legal status of sole proprietorship. In 1986 the name was changed to Autohaus Kölbl GmbH.

In 1990 the company headquarters was expanded to 5000 m². The founding of the SEAT car dealership and the S.K. Handels GmbH took place in 1995. The first prototype of an electric car from S.K. Handels GmbH was developed and presented in 2011.

In 2012, the company mainly specialized in the research and development of exhaust gas aftertreatment systems.

Today the company consists of a car dealership, a workshop with a paint shop and a research and development department which produces diesel particulate filter systems and catalytic converters - which are used to achieve a better level of particulate reduction, especially in older vehicles. In addition, the company developed a pure exhaust gas aftertreatment system (the S.K. EURO 6 SCR system) which can upgrade certain vehicles from EURO 0 to EURO 6.

The product portfolio of S.K. Handels GmbH ranges from liquefied gas conversions to increased trailer loads, trailer hitches, replacement & retrofit catalysts, diesel particle filters, soot particle filters for vehicles with 1900-4200 cm³ displacement and cat-filter combination systems to the S.K. Euro 6 SCR system.

Another related article on SCR: SCR at Wikipedia