Where is the urea nozzle installed?
2 Answers
The urea nozzle is installed on the exhaust pipe of diesel vehicles and is a key component of the diesel exhaust after-treatment system. The function of the urea nozzle is to quantitatively inject the urea aqueous solution for exhaust after-treatment, which can reduce nitrogen oxide emissions. The urea nozzle is a wearing part and needs to be cleaned and replaced frequently. In the exhaust gas treatment process, the urea injection unit injects the urea aqueous solution at the appropriate time and in the appropriate amount into the exhaust pipe, i.e., upstream of the SCR catalytic converter. The urea is then thermally decomposed and hydrolyzed into ammonia, which reduces harmful nitrogen oxides into nitrogen and water in the SCR catalytic converter.
Last time I had my car repaired, I noticed the urea nozzle was installed in the middle or front section of the exhaust pipe, right next to the SCR catalyst and not far from the engine outlet. It sprays urea solution there mainly to atomize the urea and mix it with exhaust gases, helping to reduce nitrogen oxide emissions. The location is carefully chosen because the temperature in that section of the exhaust pipe is usually around 200 degrees Celsius, which is ideal for urea to decompose into ammonia. If the nozzle gets clogged or misaligned, the car might trigger a warning light or even go into limp mode, affecting the driving experience. I remember once during a long-distance drive, the nozzle got crystallized and nearly caused a breakdown—it was only resolved after a mechanic cleaned it. For regular maintenance, I recommend car owners periodically check the nozzle for carbon buildup and use genuine AdBlue solution to avoid issues. The position may vary slightly depending on the car model—some have it near the rear chassis—but the function remains the same: maintaining environmental compliance and efficiency.
