What is the reason for adding urea to a car?
2 Answers
Adding urea to a car is primarily aimed at meeting exhaust emission standards. The exhaust contains hundreds of different compounds, and these emissions not only have a peculiar odor but can also cause dizziness, nausea, and affect human health. The function of adding urea to a car: The scientific name of automotive urea is Diesel Exhaust Fluid (DEF), which is mainly used in diesel engines. National regulations require that electronically controlled diesel engine vehicles must add urea because diesel vehicles emit a large amount of exhaust. Adding urea can reduce carbon oxides in the exhaust, lower pollutant emissions, and thus make diesel vehicles more environmentally friendly. Environmental protection departments worldwide have proposed further reductions in nitrogen oxide pollutants emitted by diesel engines. This is commonly referred to as the Euro IV standard in China. Currently, most diesel engines employ Selective Catalytic Reduction (SCR) technology. After the engine exhaust is discharged from the turbocharger, it needs to pass through a catalytic converter before entering the vehicle's exhaust pipe. The urea injector on the exhaust pipe sprays urea under the control of the vehicle's computer. When the urea solution encounters hydrocarbons emitted by the diesel engine, a chemical reaction occurs, converting the hydrocarbons into nitrogen and water, which are non-toxic to both the air and the human body.
When driving my diesel car, I noticed frequent reminders to add urea, which initially made me curious. It turns out that modern vehicles are equipped with a system called SCR to meet environmental emission standards. The nitrogen oxides in the exhaust are harmful, but when urea is added, it decomposes into ammonia, which then reacts with pollutants to form nitrogen and water, significantly reducing pollution. If you don't add it, the dashboard warning light will come on, and the car may limit speed or issue warnings, affecting driving. This policy stems from global concerns about air quality, with regions like Europe and China enforcing mandatory requirements. As a driver, I need to regularly check the tank and add AdBlue solution as per the manual, ensuring there are no leaks or deterioration. The benefits include smoother vehicle operation and avoiding fines—a win-win situation.
