What are the differences between National V and National VI engines?

[VonDallas]

The differences between National V and National VI emission standards are as follows: Different emission standards: The National VI emission standard is more than 30% stricter than National V. Excluding the influence of working conditions and testing, the carbon monoxide emissions of gasoline vehicles are reduced by 50%, the total hydrocarbon and non-methane hydrocarbon emissions are reduced by 50%, and nitrogen oxide emissions are reduced by 42%. Different implementation times: The National V standard was implemented nationwide on January 1, 2017, as the fifth phase of the national motor vehicle emission standard. National VI has been implemented since July 1, 2019. Different principles: During the National V phase, diesel and gasoline vehicles had different emission standards, but National VI adopts a fuel-neutral principle, meaning that regardless of the fuel type, the emission limits are the same. Different issuing departments: The National V standard was issued by the Ministry of Environmental Protection. The National VI standard was issued by the Ministry of Environmental Protection and the General Administration of Quality Supervision, Inspection, and Quarantine. Different letter representations: National V is represented by 'V,' while National VI is represented by 'VI.' Different monitoring requirements for plug-in hybrid electric vehicles: Compared to National V, National VI has improved monitoring requirements for plug-in hybrid electric vehicles, including energy storage systems, thermal management systems, brake regeneration, drive motors, generators, and other regulations. National V 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. National VI has two standards: National VIa and National VIb. They are as follows: National VIa 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. National VIb 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 National VI emission policy, although National V vehicles are not currently restricted from normal use, their resale value will be significantly impacted. For car owners, if they purchase a truck on loan for cargo transport, the depreciation of the vehicle after paying off 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, National VI vehicles, with longer service life and more road rights, have greater advantages.

[LaAshlyn]

With nearly two decades of experience in the automotive repair industry, I have firsthand insights into the China V and China VI emission standards. The most significant difference lies in the stricter emission controls under China VI, which substantially reduces the limits for nitrogen oxides (NOx) and particulate matter (PM) compared to China V. Technologically, China VI engines commonly incorporate additional components like Gasoline Particulate Filters (GPF) and optimized three-way catalytic converters to minimize exhaust pollution, though this also makes the system more complex and slightly increases maintenance costs. In terms of driving performance, China VI vehicles tend to offer better fuel efficiency and lower CO2 emissions in urban conditions, but their power tuning may feel more sensitive at highway speeds. From a purchasing perspective, China VI models are more favorable in environmentally conscious cities, avoiding potential traffic restrictions. However, they come at a higher price point than China V vehicles. This investment contributes significantly to long-term air quality improvement and drives industry innovation. I recommend prioritizing China VI-compliant vehicles to align with national green development goals, while emphasizing regular maintenance to prevent minor issues from escalating into costly repairs.