Why do China 6 diesel vehicles need to add urea?
2 Answers
China 6 diesel vehicles add urea solution to reduce vehicle exhaust emissions and protect the atmospheric environment. The following is an introduction to urea solution: 1. Introduction: Vehicle urea solution is a solution made from high-purity urea and pure water. 2. Description: Vehicle urea is an essential product for heavy-duty diesel vehicles to meet the China 4 emission standards. Vehicle urea refers to a urea aqueous solution with a urea concentration of 32.5% and the solvent being ultra-pure water, with raw materials being specialized vehicle urea and ultra-pure water. 3. Principle: Vehicle urea must use first-grade ultra-pure water from the electronics industry. Since the SCR catalyst carrier is highly susceptible to metal ion poisoning and thus loses its catalytic effect, vehicle urea solution must use first-grade ultra-pure water from the electronics industry.
To be honest, I didn’t understand why my China VI diesel truck had an extra urea tank when I first bought it. It wasn’t until I took a few long-haul trips that I figured it out. This thing is technically called diesel exhaust fluid (DEF), and it’s mainly used to treat harmful nitrogen oxides in the exhaust. The China VI emission standards are so strict that the engine alone can’t clean the exhaust completely, so an SCR system is added to the rear exhaust pipe. When the urea is injected, a chemical reaction occurs, turning the pungent exhaust into harmless nitrogen and water vapor. For example, the garbage trucks that pass by our neighborhood now emit white smoke without any smell. However, this stuff is consumable. I drive a 3.5-ton light truck for logistics, and a full tank can last over 2,000 kilometers. Gas stations sell it in blue 10-liter containers for about 30 yuan, so I just top it up whenever I refuel.
