Technical Standards

Key improvements of the China VI HDV emission standard are:

• Reductions in nitrogen oxide (NO_X) and particulate matter (PM) emission limits by around 70% from the China V standard;
• The introduction of particulate number (PN) limits;
• A shift from the European Steady-state Cycle (ESC) and European Transient Cycle (ETC) to the more representative and dynamic World Harmonized Stationary Cycle (WHSC) and World Harmonized Transient Cycle (WHTC);
• Inclusion of new World Harmonized Not-to-Exceed (WNTE) test;
• Extended durability requirements;
• Adoption of full vehicle Portable Emission Measurement System (PEMS) testing and requirements based on the European PEMS regulation, with modifications that address China-specific driving conditions for type tests, new production and in-service conformity testing;
• Improved on-board diagnostic (OBD) system and anti-tampering provisions based on U.S. OBD requirements;
• A requirement for vehicles to be equipped with a remote emission monitoring on-board terminal (remote OBD), the first regulation of its kind worldwide;
• A multi-component compliance program involving agency- and manufacturer-run emission tests during pre-production, production, and in-use stages;
• China’s first emission warranty program for HDVs, in which manufacturers are required to guarantee emission control components for a minimum distance travelled or service time.
• The final rule indicates that future possible requirements on CO₂ emissions from HDVs may be implemented.

Limit Values

Emission limits for China III-VI are shown below.

NH₃ slip limits began to be enforced under China V, when the NH₃ slip limit was 25 ppm (peak) and 10 ppm (cycle average). For China VI, the NH₃ slip limit is 10 ppm (cycle average). In addition to the more realistic test cycles and stringent emission limits, the China VI standard also introduces additional off-cycle test requirements, including the World Harmonized Not-to-Exceed (WNTE) test and a full-vehicle PEMS test. The test requirements and emission limits of the WNTE test in China VI are equivalent to the Euro VI standard.

PEMS Testing Requirements

China VI introduced PEMS testing for type tests, new production tests, and in-service conformity tests. The China VI PEMS testing requirements and emission limits primarily follow the Euro VI PEMS standard, with a few enhancements and modifications for the Chinese context. For data evaluation, the work-based window method is applied. A vehicle is considered adequate only if 90% or more valid windows meet emission limits. The provision also includes an innovative transient NOx concentration limit of 500 ppm, and requires that at least 95% of data points obtained from the PEMS testing not exceed this limit.

Durability requirements and emission warranties

A vehicle’s useful life in the China VI HDV standard is identical to that of Euro VI. Improved from China V, longer distance durability is now required for all vehicle categories, while service time requirements remain the same.

Starting with China VI, manufacturers are required to guarantee a number of emissions-control components in their new vehicles for a minimum distance or time. If the emissions control equipment and/or related components malfunction during the warranty period, the manufacturer is responsible for repair.

Compliance program

The China VI regulation also requires a number of agency- and manufacturer-run regulatory tests that apply to vehicle prototypes and throughout a vehicle’s useful life.

Source: China’s Stage VI emission standard for heavy-duty vehicles, ICCT.

Manufacturer-performed tests mandated by the China VI standards include four stages of testing: type test, conformity of production test, new vehicle test, and in-use conformity test. For all four manufacturer-run tests, the regulatory agency has the authority to conduct verification tests. For non-compliant vehicles, the manufacturer is required to submit a corrective action plan to the agency and subsequently implement the action plan after approval.