What is the use of urea for vehicles?
Urea is used to treat diesel engine exhaust gas. The composition of diesel engine exhaust is different from that of gasoline engine, mainly nitrogen oxides and particulate matter. Nitrogen oxides are extremely harmful, not only affecting the environment, but also causing cancer and affecting the respiratory tract. Therefore, the regulations have strict requirements on the content of nitrogen oxides in diesel engine exhaust.
How to use diesel vehicles There is an scr device on the exhaust system of urea-diesel engine, which is similar to the three-way catalytic converter of gasoline engine, and the tail gas is treated here. The nozzle is installed on the exhaust pipe in front of scr device. When the engine is working, the exhaust gas first passes through the particle trap to remove particles, and then reaches the nozzle. The injection device is powered by the compressed air provided by the vehicle, which injects urea into the exhaust system, fully mixes with the exhaust gas and releases ammonia, and then comes to the scr device to start the chemical reaction. After treatment, the contents of particulate matter and nitrogen oxides in the tail gas are reduced.
For example, in the above picture, the blue-covered car is a urea storage tank, and the big silver box next to it is an scr device, which treats the tail gas and reduces the content of nitrogen oxides. Does my car need urea? Urea tail gas treatment is a patent for diesel vehicles, and all gasoline vehicles do not need urea. Because the main pollutants in gasoline engine exhaust are carbon monoxide, nitrogen oxides and hydrocarbons, which can be oxidized and reduced with each other, the three-way catalytic converter of gasoline engine can treat the exhaust at high temperature without adding other additives. And not all diesel vehicles need urea, which will be clearly pointed out in the user manual. Million car purchase subsidy