Where is the automotive urea added?
2 Answers
Automotive urea is added into a dedicated urea storage tank, which is located near the fuel tank. Automotive urea is a colorless, transparent liquid stored in the urea tank. When the sensor detects nitrogen oxides in the exhaust pipe, it automatically sprays atomized automotive urea to mix with the nitrogen oxides. A redox reaction then occurs in the SCR reaction tank, producing and discharging non-polluting nitrogen and water. The reason for adding urea to the vehicle is: The harmful substances in diesel vehicle exhaust are mainly nitrogen oxides and particulates. While particulate emissions can be reduced through technical means inside the engine, the exhaust primarily contains nitrogen oxides. By injecting urea into the exhaust after-treatment device, the urea decomposes into ammonia at high temperatures. Under the action of a catalyst, it reacts with nitrogen oxides to produce harmless nitrogen and water.
I used to drive a diesel car and was completely confused the first time I had to add AdBlue. Later, I learned there’s a dedicated urea tank. Its location varies by vehicle model—for my SUV, the AdBlue filler cap is in a corner of the engine bay, usually marked with a blue label saying "ADBlue." After parking and turning off the engine, just open the cap and pour in the dedicated urea solution. Don’t forget to use only standard-compliant urea fluid, typically with a concentration of 10% to 20%. Too many impurities can clog the system. If you don’t add urea, the SCR system will trigger a warning light, and the car might go into limp mode or consume much more fuel. For environmental reasons and vehicle maintenance, I refill it regularly, especially checking before long trips.
