What is the purpose of urea used in large vehicles?

[VanVictoria]

Vehicles use urea primarily to reduce harmful nitrogen oxides in the exhaust into nitrogen and water. Below is a partial introduction to urea: 1. The main harmful substances in diesel vehicle exhaust are nitrogen oxides and particulates. While particulate emissions can be reduced through technical means inside the engine, nitrogen oxides remain predominant in the exhaust. Urea is injected into the exhaust after-treatment device to address this. 2. Urea decomposes into ammonia at high temperatures, which then reacts with nitrogen oxides in the presence of a catalyst, producing harmless nitrogen and water. This device is called the SCR (Selective Catalytic Reduction) after-treatment system. 3. Automotive urea plays a crucial role in vehicle power and fuel consumption. Failure to use diesel exhaust fluid (DEF) or the use of urea solutions with insufficient purity or inferior quality can cause the vehicle's engine to automatically reduce speed.