What are the differences between National 5 and National 6 standards for the Envision?
4 Answers
The differences between National 5 (China 5) and National 6 (China 6) emission standards are as follows: Different emission standards: The National 6 standard is more than 30% stricter than National 5. Excluding the influence of working conditions and testing, gasoline vehicles' carbon monoxide emissions are reduced by 50%, total hydrocarbons and non-methane hydrocarbons emissions are reduced by 50%, and nitrogen oxide emissions are reduced by 42%. Different implementation times: The National 5 standard was implemented nationwide on January 1, 2017. The National 6 standard has been implemented since July 1, 2019. Different principles: During the National 5 phase, diesel and gasoline vehicles had different emission standards. However, National 6 adopts a fuel-neutral principle, meaning the emission limits are the same regardless of the fuel type. Different issuing authorities: The National 5 standard was issued by the Ministry of Environmental Protection. The National 6 standard was jointly issued by the Ministry of Environmental Protection and the General Administration of Quality Supervision, Inspection and Quarantine. Different letter representations: National 5 is represented by 'V', while National 6 is represented by 'VI'. Different monitoring requirements for plug-in hybrid electric vehicles: Compared to National 5, National 6 has improved monitoring requirements for plug-in hybrid vehicles, including regulations on energy storage systems, thermal management systems, brake regeneration, drive motors, generators, etc. National 5 standard limits are as follows: Gasoline vehicles must not emit more than 1,000 mg of carbon monoxide per kilometer driven. They must not emit more than 68 mg of non-methane hydrocarbons per kilometer. They must not emit more than 60 mg of nitrogen oxides per kilometer. They must not emit more than 4.5 mg of PM (particulate matter) per kilometer. National 6 has two standards: National 6a and National 6b, as follows: National 6a standard limits: Gasoline vehicles must not emit more than 700 mg of carbon monoxide per kilometer driven. They must not emit more than 68 mg of non-methane hydrocarbons per kilometer. They must not emit more than 60 mg of nitrogen oxides per kilometer. They must not emit more than 4.5 mg of PM per kilometer. National 6b standard limits: Gasoline vehicles must not emit more than 500 mg of carbon monoxide per kilometer driven. They must not emit more than 35 mg of non-methane hydrocarbons per kilometer. They must not emit more than 35 mg of nitrogen oxides per kilometer. They must not emit more than 3 mg of PM per kilometer. Affected by the National 6 emission policy, although National 5 vehicles are not currently restricted in normal use (no traffic restrictions or license plate limitations), their resale value will be significantly impacted. For car owners, if they purchase a truck for freight transport via loan, the vehicle's depreciation 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, National 6 vehicles with longer service life and more road rights have greater advantages.
The main differences between the Buick Envision's China 5 and China 6 standards lie in the emission system and policy compliance. The China 6 standard is more stringent, requiring reductions in pollutants such as carbon monoxide and nitrogen oxides, prompting automakers to optimize the engine and control modules. For instance, the China 6 version incorporates a particulate filter to treat exhaust particles, which may not be integrated in the China 5 version. The ECU programming has also been recalibrated to improve fuel efficiency, resulting in a slight but not significant reduction in actual driving fuel consumption. In terms of power output, there is little difference between the two, with the China 6 version being slightly smoother at low speeds. For maintenance, the China 6 system is more complex, with slightly higher replacement costs for components such as catalytic converters, but it offers better environmental performance. Regarding environmental policies, the China 6 version meets the new regulations and can be registered normally in cities with driving restrictions, while the China 5 version is gradually being restricted. For daily use, it is recommended to use high-quality fuel for China 6 vehicles to avoid clogging the system.
I'm particularly interested in the actual purchase and ownership costs of the Envision's China 5 and China 6 models. Due to the addition of emission control technologies, the China 6 models typically cost a few thousand yuan more when buying new, but they save the hassle of registration in license-restricted cities. For daily refueling, China 6 vehicles are more sensitive to fuel quality, so it's best to use higher-grade gasoline to reduce the risk of malfunctions. There's little optimization in fuel consumption, which is basically the same as China 5, saving less than 0.5 liters per 100 kilometers on average. In terms of maintenance, the China 6 system includes additional sensors and filters, which may increase repair costs slightly, but in the long run, they have higher resale value. I've driven both models and didn't notice much difference in power, but the China 6 has an advantage in policy adaptability, especially with the stricter China 6b phase.
From an environmental perspective, the Envision's China VI version is an upgraded model with significantly stricter emission limits compared to China V. The China VI standard reduces hydrocarbon and particulate emissions, contributing to improved air quality. Driven by policy, China VI-compliant vehicles can be registered normally, while China V models cannot. The engine tuning remains similar, with a slight increase in fuel efficiency.
