The differences between National III diesel engines and National II diesel engines are: different fuel efficiency, different precious metal content in the catalytic converter, and different costs.

1. Differences in fuel efficiency

Compared with National II diesel engines, National III diesel engines are more fuel-efficient. A model of about 5 tons saves about 1 liter per 100 kilometers, and a model of 10 tons saves about 2L. But the premise is long distance and stable driving. Driving operations in a small area have little impact on fuel consumption.

2. The precious metal content in the catalytic converter is different

In order to meet the National III diesel engine emission standards, the precious metal content in the catalytic converter is nearly 1 times higher than that of the National II diesel engine (generally Just add a catalytic converter). The precious metals (platinum, iridium, palladium, etc.) coated on the surface of the filter element are used to further oxidize (burn) harmful components such as CO, HC, and NOX in the exhaust gas into harmless substances such as CO2 and water.

3. Cost differences

The cost of National III diesel engines is much higher than that of National II diesel engines, so the price of the vehicle will naturally rise.

Baidu Encyclopedia - National Phase III Motor Vehicle Pollutant Emission Standards