Diesel engine exhaust gas is becoming a problem and regulations are becoming increasingly strict. Automobile manufacturers and construction equipment manufacturers are making various efforts to comply with strict regulations and one solution is the “urea SCR system”.
The urea SCR system is the name of a system that purifies exhaust gas by decomposing nitrogen oxides (NOx), the main cause of air pollution, into nitrogen and water. It is adopted in vehicles equipped with diesel engines such as trucks, buses, regular vehicles, and construction equipment. SCR is an abbreviation for “selective catalytic reduction”, and thus the literal translation of the SCR system is “selective contact (catalytic) reduction system. What is essential to this urea SCR system is the high-quality urea solution, AdBlue®.

How is exhaust gas purified by urea?

The urea SCR system has two stages of catalysts that purify exhaust gas.

①The oxidation catalyst renders hydrocarbons and carbon monoxide emitted by diesel engines harmless.

②By injecting AdBlue® at high temperatures inside the muffler and passing it through a catalyst called an SCR catalyst, a chemical reaction occurs between hydrolyzed ammonia gas (NH3) and nitrogen oxides (NOx), releasing harmless nitrogen(N2) and water(H2O) into the atmosphere.

This way, AdBlue® is required to operate a urea SCR system.