According to the national standard (GB252-87), light diesel fuel is classified into six grades-10, 0, -10, -20, -35, and -50-based on their pour points. These grades indicate pour points of no higher than 10°C, 0°C, -10°C, -20°C, -35°C, and -50°C, respectively; the higher the grade number, the lower the pour point.
Diesel is a specialized fuel used in compression-ignition engines (i.e., diesel engines). It appears as a water-white, pale yellow, or brownish liquid. Diesel fuel is categorized into two types: light diesel and heavy diesel. Light diesel is used in high-speed diesel engines operating at speeds above 1,000 rpm, while heavy diesel is used in medium- and low-speed engines operating at speeds below 1,000 rpm. The diesel sold at standard service stations is light diesel. Light diesel products comply with the GB 252-2000 "Light Diesel Fuel" standard, which classifies the fuel into grades 10, 5, 0, -10, -20, -35, and -50 based on the pour point.
The Cold Filter Plugging Point (CFPP) is a key indicator of light diesel's low-temperature performance; it reflects actual operational performance in cold conditions and most closely approximates the fuel's lowest practical operating temperature. When selecting a diesel grade, users should consider both the local ambient temperature and the CFPP associated with that specific grade. The CFPP values are 8°C for Grade 5 light diesel, 4°C for Grade 0, -5°C for Grade -10, and -14°C for Grade -20.
