The requirement for automotive urea solution is typically referred to as diesel exhaust fluid (DEF) or AdBlue.
The urea solution must meet ISO 22241 standards.
The urea concentration in the solution must be 32.5% +/- 0.5%.
The solution must be clear, colorless, and free of sediment.
The urea solution must not contain any contaminants that could harm the SCR (selective catalytic reduction) system, such as metal ions or other impurities.
The urea solution must be stored and handled properly to prevent contamination, degradation, and freezing.
The urea solution must be compatible with the specific SCR system used in the vehicle, as recommended by the manufacturer.
The ultra-pure water standrad
The urea solvent must be ultra-pure water. Ultra-pure water refers to water that is free of any impurities or minerals, and the most common form of pure water is distilled water. The "National Standard for Automotive Urea" GB 29518-2013 "Diesel Engine Nitrogen Oxide Reducing Agent Urea Aqueous Solution (AUS32)" was published by the General Administration of Quality Supervision, Inspection and Quarantine and the National Standardization Committee on May 7, 2013, and came into effect on July 1, 2013! AUS32 refers to urea produced in industry that contains only trace amounts (very small amounts) of biuret, ammonia, and water, without aldehydes or other substances (such as anti-caking agents), and without sulfur and sulfides, chlorides, nitrates, and other compounds.
The CHINA ultra-pure water standrad
The pump and container for AUS32 that comply with this standard should be labeled as follows: AUS32 GB 29518. It is reported that some cities, such as Beijing and Shanghai, have issued local standards on vehicle urea of different versions before (or ahead of) the implementation of the National IV standard for heavy-duty diesel vehicles. In April 2013, the China Automotive Engineering Society also issued the Technical Specification for Vehicle Urea Solution compiled by the society. Now the national standard version GB 29518-2013 has been issued and implemented, which will become the unified standard in China.
