Why Do Diesel Vehicles Need Urea Solution?
3 Answers
Diesel vehicles add urea solution to reduce exhaust emissions and protect the atmospheric environment. The use of urea in vehicles is to convert harmful nitrogen oxides in the exhaust into nitrogen and water. The exhaust emitted by engines is extremely harmful to the atmospheric environment. With increasingly stringent environmental regulations, exhaust treatment systems have been developed to ensure compliance. The primary harmful substances in diesel exhaust are nitrogen oxides and particulates. The exhaust treatment system can reduce particulate emissions. Once urea is used in the vehicle, as long as the engine is running, the urea is injected into the exhaust treatment system, where it decomposes into ammonia gas at high temperatures.
Diesel vehicles use urea solution primarily due to environmental requirements. I've known this for several years because I drive a diesel truck myself. Modern diesel vehicles are equipped with an SCR (Selective Catalytic Reduction) system designed to reduce harmful gas emissions from the exhaust. Specifically, when urea solution is injected into the exhaust system, it reacts with nitrogen oxides, converting them into harmless nitrogen and water, thereby preventing air pollution. This is mandated by strict environmental regulations, requiring all new vehicles to be equipped with this system. Failure to use urea solution results in exceeding emission standards, which can lead to fines or restrictions on road use. I think this is quite good—protecting the environment is everyone's responsibility, and cleaner air means healthier breathing for all. The urea solution needs to be refilled every few thousand kilometers, and I use a reputable brand of urea solution, which is not expensive.
From a technical perspective, adding urea solution to diesel vehicles is part of the Selective Catalytic Reduction (SCR) system. I've repaired many vehicles, and this system injects urea solution into the exhaust to break down nitrogen oxides in the emissions into harmless substances. The principle is simple: at high temperatures, the urea solution decomposes into ammonia, which then reacts with harmful gases to produce nitrogen and water vapor. If you don't add it, the system will trigger warnings, illuminate warning lights, or limit engine power, affecting driving safety. During routine maintenance, it's essential to check the urea solution level and quality, ensuring the injector nozzles aren't clogged. I've used several brands and found that regular top-ups to prevent freezing are crucial. The cost isn't high, but it extends the catalytic converter's lifespan, reduces engine load, and is cost-effective in the long run. Make it a habit to check whenever you refuel.
