Why do cars need to add urea now?
2 Answers
Nowadays, cars add urea mainly 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 can reduce carbon oxides in the exhaust and lower pollutant emissions, making diesel vehicles more environmentally friendly. Currently, most diesel engines use Selective Catalytic Reduction (SCR) technology, meaning that 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 nozzle on the exhaust pipe will spray urea under the control of the onboard computer.
Oh, when it comes to adding urea to cars, it's actually a technical requirement specifically designed for diesel vehicles. In my opinion, it's mainly to address emission issues. Modern diesel engines produce harmful gases like nitrogen oxides. When urea solution is injected into the vehicle's exhaust pipe, it reacts with nitrogen oxides through a system called SCR (Selective Catalytic Reduction), converting them into harmless water vapor and nitrogen gas, thereby significantly reducing pollution. If you don't add it, the system may limit vehicle performance, such as restricting speed, and warning lights may come on. I think this is progress—it makes the engine run more efficiently and improves fuel economy. For vehicle owners, adding urea isn't expensive and usually aligns with refueling frequency, just a minor habit change.
