What are the differences between National III and National IV diesel vehicles?
3 Answers
There are mainly the following differences between National III diesel and National IV diesel: 1. Sulfur content: The sulfur content of National IV diesel is significantly lower compared to National III diesel. National III diesel contains much higher sulfur content than National IV. 2. Diesel stability: National IV diesel has good oxidation stability, is less prone to discoloration and deterioration, and is less likely to form sediments and gums. 3. Benzene and hydrocarbon content: The benzene and hydrocarbon content in National IV diesel is greatly reduced, while National III diesel has relatively higher benzene and hydrocarbon content. 4. Diesel quality: National IV diesel has seen a significant improvement in quality compared to National III. Overall, National IV diesel is a new standard diesel that emerged in accordance with the National IV emission standards. The introduction of National IV diesel represents an improvement in diesel quality, with greater emphasis on environmental protection requirements compared to National III. Whether in terms of emission quality or diesel quality, National IV outperforms National III, better reflecting the country's requirements for low-emission environmental protection.
I drove a National III diesel car for several years before switching to a National IV model last year, and the differences are quite noticeable. First, regarding emission restrictions, the National IV standards impose stricter controls on exhaust, with higher environmental requirements, resulting in significantly less pollution. Nowadays, major cities enforce strict checks, often restricting National III vehicles, which can be quite troublesome. Technically, National IV vehicles are equipped with new systems like the Selective Catalytic Reduction (SCR) device—sounds professional, but it basically uses urea to purify exhaust, requiring regular urea refills, which adds a bit to maintenance costs. Fuel consumption is slightly higher in National IV models, but the difference isn’t significant, especially on long trips. In terms of lifespan, National III cars are older, with parts aging faster and needing more frequent repairs, while National IV models are more modern, with more reliable engines, though system repairs can be costlier. Policy-wise, many regions are pushing to phase out National III vehicles with subsidies, so if you own one, it’s best to consider upgrading soon to avoid sudden penalties. Overall, from a practical standpoint, National IV offers more peace of mind and is more eco-friendly, though at a slightly higher cost, making it better suited for modern urban driving.
As someone quite fascinated by automotive technology, the core difference between National III and National IV diesel vehicles lies in their emission control mechanisms. The National IV standard is an upgraded version of National III, with over 50% stricter limits on nitrogen oxides and particulate matter emissions, meaning significantly cleaner exhaust. Technically, National IV vehicles often rely on SCR systems or exhaust gas recirculation valves—the former uses urea solution to convert harmful gases, while the latter reduces engine exhaust emissions. However, adding these components makes the system more complex, with common failure points being sensors or urea pump issues. In terms of performance impact, National IV engines are optimized for stronger low-speed torque, but overall fuel consumption may increase by around 10%, which isn’t deeply noticeable without a careful test drive. From a regulatory perspective, national policies mandate National IV vehicles to include OBD diagnostic systems for real-time emission monitoring, alerting for repairs if standards are exceeded; conversely, National III vehicles lack this and may face issues during inspections. Maintenance-wise, National IV vehicles have more parts and slightly higher upkeep costs, but they can extend engine life in the long run. If you’re currently choosing a vehicle, prioritizing National IV is advised—it’s both eco-friendly and future-proof.
