Why do some vehicles need to add urea?
2 Answers
The reason some vehicles add urea is to meet emission standards. Only diesel vehicles require urea addition. National regulations mandate that electronically controlled diesel engine vehicles must add urea because diesel vehicles emit higher levels of exhaust gases. Adding urea helps reduce carbon oxides in the exhaust and lowers pollutant emissions, making diesel vehicles more environmentally friendly. Currently, most diesel engines employ Selective Catalytic Reduction (SCR) technology. This means that after the engine exhaust exits the turbocharger and before entering the vehicle's exhaust pipe, it first passes through a catalytic converter for transformation. The urea nozzle on the exhaust pipe sprays urea under the control of the vehicle's computer. The urea and nitrogen oxides in the exhaust undergo redox reactions in the catalytic converter, ultimately converting the vehicle's exhaust gases into nitrogen and water before being emitted.
I've been driving diesel vehicles for years and know that adding urea is crucial for emission control. Urea solution, such as AdBlue, is injected into the exhaust system to react with harmful nitrogen oxides, converting them into harmless nitrogen and water, all thanks to Selective Catalytic Reduction (SCR) technology. Environmental regulations mandate that vehicles must reduce pollution, and failure to add urea may result in the engine limiting power or triggering fault codes. The benefits include cleaner vehicle operation, compliance with emission standards, and improved fuel efficiency. Regularly topping up the urea solution and maintaining the SCR system is essential, similar to refueling frequency, depending on the vehicle model and mileage, with long-distance drivers particularly needing to monitor urea tank levels.
