What is the composition of diesel vehicle urea?
2 Answers
Automotive urea refers to a urea aqueous solution with a urea concentration of 32.5% and a solvent of ultra-pure water. The raw materials are specialized automotive urea and ultra-pure water. Automotive urea is an essential product for heavy-duty diesel vehicles to meet the National IV emission standards. Below is relevant information about automotive urea: 1. Introduction: To achieve the National IV emission standards, heavy-duty trucks, buses, and other diesel vehicles must use an appropriate SCR system for exhaust treatment. This system requires the use of a urea solution to treat nitrogen oxides in the exhaust. Therefore, automotive urea solution has become an essential product for heavy-duty trucks and buses to meet the National IV emission standards. 2. Usage instructions: Automotive urea must use Grade 1 ultra-pure water from the electronics industry. Since the SCR catalyst carrier is highly susceptible to metal ion poisoning, which can deactivate the catalyst, the urea solution must use Grade 1 ultra-pure water from the electronics industry. The automotive urea solution begins to freeze at -11°C and completely solidifies at -20°C in practical use. Current technology involves adding modifiers to lower the solution's freezing point and external heating devices to prevent solidification.
I just checked that urea used in diesel vehicles is actually not ordinary fertilizer, but a specially formulated liquid. The main components are quite simple – 32.5% high-purity urea dissolved in 67.5% deionized water. Its technical name is Diesel Exhaust Fluid (DEF), stored in a dedicated tank in the vehicle. Every time I refuel, I make sure to check its fluid level as the vehicle will alert me if it's low. A truck driver friend told me the filler cap is deliberately designed with a blue lid to prevent accidentally adding the wrong liquid. Passing annual emission tests relies entirely on it breaking down nitrogen oxides in exhaust gases. By the way, this stuff is corrosive – if it spills on car paint during refilling, it must be rinsed immediately. Once I spilled some and didn't deal with it promptly, causing the car paint to bubble.
