What is the difference between China 6 and China 5 fuel?

[KingstonMarie]

The differences between China 5 and China 6 emission standards are as follows: Different emission standards: China 6 emission standards are more than 30% stricter than China 5. Excluding the influence of working conditions and testing, gasoline vehicles' carbon monoxide emissions are reduced by 50%, total hydrocarbon and non-methane hydrocarbon emissions are reduced by 50%, and nitrogen oxide emissions are reduced by 42%. Different implementation times: The China 5 standard was implemented nationwide on January 1, 2017, as the fifth stage of the national motor vehicle emission standard. China 6 was implemented starting from July 1, 2019. Different principles: During the China 5 phase, diesel and gasoline vehicles had different emission standards, but China 6 adopts a fuel-neutral principle, meaning that regardless of the fuel type, the emission limits are the same. Different issuing departments: The China 5 standard was issued by the Ministry of Environmental Protection. The China 6 standard was issued by the Ministry of Environmental Protection and the General Administration of Quality Supervision, Inspection, and Quarantine. Different letter representations: China 5 is represented by 'V,' while China 6 is represented by 'VI.' Different monitoring requirements for plug-in hybrid electric vehicles: Compared to China 5, China 6 has improved monitoring requirements for plug-in hybrid electric vehicles, including energy storage systems, thermal management systems, brake regeneration, drive motors, generators, and other regulatory aspects. China 5 standard limits are as follows: Gasoline vehicles must not emit more than 1,000 milligrams of carbon monoxide per kilometer driven. Gasoline vehicles must not emit more than 68 milligrams of non-methane hydrocarbons per kilometer driven. Gasoline vehicles must not emit more than 60 milligrams of nitrogen oxides per kilometer driven. Gasoline vehicles must not emit more than 4.5 milligrams of PM fine particles per kilometer driven. China 6 has two standards: China 6a and China 6b, as follows: China 6a standard limits: Gasoline vehicles must not emit more than 700 milligrams of carbon monoxide per kilometer driven. Gasoline vehicles must not emit more than 68 milligrams of non-methane hydrocarbons per kilometer driven. Gasoline vehicles must not emit more than 60 milligrams of nitrogen oxides per kilometer driven. Gasoline vehicles must not emit more than 4.5 milligrams of PM fine particles per kilometer driven. China 6b standard limits: Gasoline vehicles must not emit more than 500 milligrams of carbon monoxide per kilometer driven. Gasoline vehicles must not emit more than 35 milligrams of non-methane hydrocarbons per kilometer driven. Gasoline vehicles must not emit more than 35 milligrams of nitrogen oxides per kilometer driven. Gasoline vehicles must not emit more than 3 milligrams of PM fine particles per kilometer driven. Affected by the China 6 emission policy, although China 5 vehicles are not currently restricted from normal use, such as travel or license plate restrictions, their resale value will be significantly impacted. For truck owners, if they purchase a truck on loan for freight transport, the depreciation of the vehicle after repaying the loan is equivalent to the net profit earned during that period. A higher residual value means more profit for the owner. Therefore, from this perspective, China 6 vehicles, with longer service life and more road rights, have greater advantages.

[SanCarlos]

The biggest difference between China VI and China V fuels lies in the sulfur content. China V gasoline has a sulfur content of 10ppm, while China VI directly reduces it to below 10ppm, with the minimum reaching 5ppm. Lower sulfur content naturally reduces engine carbon deposits, and harmful substances like carbon monoxide in exhaust emissions can be reduced by over 15%. The additives have also been upgraded, with China VI fuel containing more detergents, making components like fuel injectors less prone to gumming. Nowadays, new vehicles come equipped with particulate filters, and only by using China VI fuel can this component be properly protected—otherwise, replacing a clogged one could cost thousands. However, it's worth noting that some older vehicles might trigger a fault warning light after using China VI fuel, as the cleaner fuel may dislodge long-accumulated carbon deposits. When refueling, always check the fuel grade to avoid accidentally using the wrong type.

[WalkerLee]

I think the main difference lies in environmental performance. China VI fuel not only halves the sulfur content but also imposes stricter controls on carcinogens like benzene. Upgrading from China V to China VI is equivalent to reducing two kilograms of pollutants per ton of gasoline, and the carbon deposit formation rate can drop by over 30%. At gas stations, you often see different grades of fuel nozzles—it's recommended that new cars directly use China VI fuel, as components like the three-way catalytic converter are quite delicate. Recently, I took a long trip in an older car using China V fuel, and the fuel consumption per 100 kilometers was a full liter higher than with China VI. The impact of fuel quality on daily expenses is quite tangible.

[OPresley]

Simply put, it's an upgrade in cleanliness. China VI fuel utilizes high-density hydrodesulfurization technology, containing significantly fewer impurities compared to China V fuel. This ensures better compatibility with the GPF (Gasoline Particulate Filter) in China VI vehicles, reducing clogging risks. The most noticeable real-world differences are reduced smoke during cold starts and significantly fainter exhaust odors. A reminder for car owners: some regions still sell China V fuel—if your fuel cap says 'China VI recommended,' don't compromise for cheaper lower-grade fuel.