What are the differences between National V and National VI vehicles?
4 Answers
Differences between National V and National VI vehicles: 1. Different emission standards: National V vehicles reduce nitrogen oxide emissions by 25% and particulate matter emissions by 20%; National VI vehicles reduce nitrogen oxide emissions by 77% and particulate matter by 67%. 2. Different fault classification levels: National V vehicles have a single-level fault classification; National VI vehicles have a four-level fault classification. There is no fundamental difference in the engines between National V and National VI models, whether in terms of power, performance, or combustion ratio. The difference in emission standards is due to an additional three-way catalytic converter purification device installed at the exhaust position of the vehicle.
From my experience driving so many cars, the biggest difference between China V and China VI vehicles lies in the emission system. The exhaust treatment system in China VI cars is much more complex - even the three-way catalytic converter has been structurally redesigned, and they've added new components like particulate filters. The result is increased ownership costs - you must use low-ash engine oil during maintenance, otherwise the particulate filter gets clogged easily. Last winter, my friend's China VI SUV kept showing warning lights frequently, and the mechanic said it was due to too many short trips causing particulate filter clogging that required high-speed driving for regeneration. There are also 7-8 additional sensors monitoring emissions in real-time through the computer, triggering alerts at the slightest non-compliance. Of course, the benefit is genuinely better environmental protection, though daily driving feels no different.
Last time I helped my nephew choose a car, I realized that the China 6 emission standard isn't just about numerical changes. The testing method has completely changed - while it used to be laboratory bench tests, China 6 requires additional Real Driving Emission (RDE) tests. I've seen data from test vehicles driving around with instrument packages on the streets. To meet the standards, automakers had to install EGR (Exhaust Gas Recirculation) systems, and some even changed turbocharger models. The most noticeable change is the narrower fuel filler neck to prevent accidentally using low-quality gasoline. Mechanic Zhang once complained to me that China 6 vehicles have 30% more engine fault codes than China 5 vehicles, and even replacing an oxygen sensor costs nearly a thousand yuan. You need to be extra careful when buying used cars too, as some early China 6a models now face transfer restrictions.
I remember studying the specifications in detail when changing cars last year. The China 6 standard nearly halved the emission limits, for example, reducing carbon monoxide from 1000mg per kilometer to 500mg. Technologically, it added an active carbon canister that can absorb fuel tank vapors even after the engine is turned off. The most crucial upgrade was the OBD system to version 6.0, which can monitor the oxygen storage capacity of the catalytic converter. The practical impact is that the fuel pump nozzle shuts off noticeably slower, and the maintenance interval has been shortened to 5,000 kilometers. Once during a repair, the technician showed me the inside of the exhaust pipe—the honeycomb-structured GPF filter was denser than a coffee filter.
