Let’s talk about Selective Catalytic Reduction (SCR). It is a technology that uses an exhaust fluid system based on urea (DEF) and a catalytic converter to significantly reduce nitrogen oxides (NOx) emissions. SCR is the main technology being used to satisfy 2010 emission regulations in US.

SCR technology works by reducing NOx (nitrogen oxides emitted by the engine) levels that are harmful to your health and the environment. SCR technology is an after treatment that treats the engine output gases. Small amounts of fluid for diesel exhaust systems (DEF) are injected to the output gases hot flow, where it vaporizes and decomposes producing ammonia and carbon dioxide. Ammonia (NH3) is the product that together with the SCR catalytic system converts nitrogen oxides (NOx) into nitrogen (N2) and water (H20).

What are the advantages of using SCR technology for trucks fleet today?
Cummins engines cover market needs in these challenging economic times that we are living in. Cummins engines with SCR will provide substantial fuel savings above 5%. The SCR catalytic technology reaches a much higher conversion efficiency of nitrogen oxides (NOx), therefore allowing the engine to be fully optimized. An additional benefit is the reduction of the frequency of changing the particulate filter (DPF), which reduces the maintenance costs.

tips de mecanica-105-2The Diesel exhaust fluid system (DEF) is the reagent for SCR system functionality. It is an aqueous solution of urea, a nitrogen compound which is converted to ammonia with heat. It must be mixed thoroughly with a 32.5% pure urea and 67.5% de-ionized water.

The DEF product that you buy must be certified at the German Institute of Standardization DIN70700, the International Organization for Standardization ISO 22241-1, and must have the AUS – 32 specification. This will ensure proper purity and concentration (32.5%) of the product.

Could this product freeze in the vehicle tank while it’s operated?
The SCR system is designed to provide heat to the DEF tank and lines. The SCR heating system is designed to quickly turn the DEF to a liquid form and vehicle operation will not be affected. The DEF freezing and melting will not cause product degradation. ETM


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