What is the purpose of urea used in automobiles?

[LaAnastasia]

The role of automotive urea is as follows: 1. Automotive urea is an essential additive for the SCR (Selective Catalytic Reduction) method, used to reduce nitrogen oxide pollution in diesel vehicle exhaust. Its composition consists of 32.5% high-purity urea and 67.5% deionized water. 2. When nitrogen oxides are detected in the exhaust pipe, the urea tank automatically sprays diesel exhaust fluid (DEF). The DEF and nitrogen oxides undergo a redox reaction in the SCR catalytic reaction tank, producing non-polluting nitrogen and water vapor that are then expelled. 3. If the diesel exhaust fluid is not loaded, or if its purity is insufficient, or if it is of poor quality, the vehicle's engine will automatically decelerate. Additionally, poor-quality DEF can contaminate the catalyst in the SCR catalytic reaction tank, leading to severe consequences.