An examination of China 7 emissions regulations

In June 2023, at F+L Week in Kuala Lumpur, Malaysia, Dr. Qingyuan Song, chief engineer of policy & regulatory affairs at Geely Powertrain, emphasised the bleak outlook for internal combustion engines (ICE). “Conventional ICE vehicles have no chance of survival in China,” Song declared. This statement is supported by the rapid adoption of new energy vehicles (NEVs) in China, driven by significant financial subsidies and aggressive government policies. In 2023, NEVs accounted for 34.7% of the 26 million passenger vehicles and 11.1% of the 9.5 million commercial vehicles sold in China, highlighting the shift towards more sustainable transportation options.

From January to April 2024, NEV sales in China continued to surge. During this period, China saw a 36% year-on-year increase in NEV retail sales, totaling 1.84 million units. This impressive growth highlights the ongoing momentum in the adoption of electric vehicles and other NEVs within the country. BYD remained the leading NEV manufacturer, with a market share of 34.3% for the January to April period, reflecting a 19.6% year-on-year growth. U.S. automaker Tesla ranked fourth with 6.7% of the market, despite a 7.6% decrease in sales compared to the previous year.

These figures indicate a strong and growing market for NEVs in China, driven by supportive government policies, financial incentives, and increasing consumer demand for sustainable transportation options. This trend underscores the rapid transformation of China’s automotive market towards greener alternatives.

While pure ICE vehicles may not be viable in the long term, immediate bans on ICE and fossil fuels are unrealistic, according to Dr. Reggie Zhan, president of Emissions Consulting Service, LLC. With more than 30 years of experience, Zhan is a technical expert for several major industry organisations, including the Chinese Society of Internal Combustion Engine (CSICE) and the Manufacturers of Emission Controls Association (MECA) in the U.S.A. His experience includes work at the Southwest Research Institute (SwRI) and Ford Motor Company, focusing on emissions control and alternative-fueled vehicle technologies.

During F+L Week 2024, held in Ho Chi Minh City, Vietnam, from March 7-8, Zhan charted a pathway towards carbon neutrality in China’s transportation sector. He emphasised the vital role of China 7 criteria and greenhouse gas (GHG) emission regulations in meeting China’s long-term environmental goals.

Development programs for the China 7 emissions standards are being carried out and will be initiated very soon. The draft proposals are expected for public comments by the end of this year or early next year, says Zhan.

Key features of China 7 emission standards

• Stricter Emission Limits: China 7 will significantly reduce allowable levels of nitrogen oxides (NOx), particulate matter (PM), and carbon monoxide (CO) compared to the current China 6 standards.
• Implementation Timeline: It is anticipated that the draft regulation will likely be published by the end of 2024 or early 2025 and implemented before 2030.
• Focus on Transparency: Manufacturers will be required to disclose detailed emissions test results and information on pollution-control technologies to ensure compliance with the new standards.
• Impact on the Market: The transition to China 7 is expected to drive advancements in vehicle technology and increase the market share of electric and hybrid vehicles as manufacturers strive to meet the new requirements.

China’s current and future emissions standards

China has modelled its vehicle emissions standards on the European Union’s regulations, implementing similar stages known as “China” standards that are comparable to the Euro standards. For example, “China 5” emission standards are roughly equivalent to the Euro 5 standards. This approach has allowed China to progressively tighten its emissions regulations in line with international best practices. Starting with China 6, a few critical elements, such as on-board diagnostics (OBD), evaporative emissions control (EVAP), etc., showed significant deviations from Euro 6.

With China 7, China is charting its own course with increasingly stringent regulations, diverging from Euro 7.

The current national emission standard, China 6, was implemented in two phases, in January 2021 and July 2023. China 6 incorporates regulatory elements from both European and U.S. standards, with additional China-specific components. China-specific rules include gaseous emissions limits and durability, wider ambient conditions and fuel quality requirements. China 6b, the subsequent phase, further tightened emissions limits, particularly targeting gaseous pollutants like NOx. The standard incorporates measures for improving durability, akin to the future Euro 7 standards, aiming to enhance the long-term performance and compliance of vehicles.

During his presentation, Zhan outlined potential changes to China’s light-duty (LD) and heavy-duty (HD) emissions regulations, including possible technology options to meet the China 7 standards.

Air quality improvements require China 7 to significantly reduce volatile organic compound (VOC) emissions from light-duty and other gasoline vehicles, says Zhan. He emphasised the pressing need for tighter control of evaporative emissions from vehicle fuel systems and refilling operations.

Analysis of emissions results from China 6 vehicles has indicated that cold-start and other fuel-rich operations result in significantly higher criteria emissions. More stringent requirements for PM and particle number (PN) are expected, which may require the use of gasoline particulate filters (GPF) for all light-duty vehicles.

Fuel and technology neutrality

Zhan emphasised the requirement for fuel and technology neutrality. GHG emissions requirements, including carbon dioxide (CO₂), nitrous oxide (N₂O), and methane, will be aligned with fuel consumption standards for both LD and HD vehicles. Limits are likely to be established for weight-class-based vehicle models as well as the corporate average of all HD vehicle models, he says.

For HD vehicles, PM and NOx are the key focus. China 7 aims to significantly reduce NOx emissions from HD diesel vehicles and non-road machinery. Cold-start and low-load operating conditions will receive closer scrutiny. Zhan highlighted the potential introduction of Low-Load Cycle (LLC) and Non-Road LLC (NR-LLC) testing in China 7 and non-road Stage 5 standards to reduce low-load and idle NOx emissions. Low-Load Cycle (LLC) and Non-Road Low-Load Cycle (NR-LLC) emissions testing are specific testing procedures designed to evaluate vehicle emissions under particular operating conditions, focusing on scenarios where engines operate at low loads. These testing cycles are especially relevant for accurately assessing emissions during real-world driving conditions, which often include a significant amount of low-load operation.

Potential NOx limits and durability requirements

Zhan outlined potential NOx limits of 20 mg per km for LD vehicles, down from the current 35 mg per km. By comparison, the proposed Euro 7 NOx limit for gasoline LD vehicles is 60 mg per km, the same as the current Euro 6 standard. For HD vehicles, Zhan indicated a proposed limit of 115 mg per kWh, and for non-road machinery, a limit of 200 mg per kWh.

China’s current emissions standards include stringent durability requirements to ensure that vehicles maintain low emissions over their operational lifespan. On-board diagnostics (OBD-II) and on-board monitoring (OBM) report aspects of the vehicle’s performance, particularly emissions-related components. OBD-II systems offer a standardised, more comprehensive, and user-friendly diagnostic experience compared to the limited and manufacturer-specific OBD-I systems​. He noted the continued use of telematics, a technology primarily used to monitor a vehicle’s location, movements, status, and behaviour, to transmit real-time global positioning and emissions-related data from HD vehicles, with additional parameters.

Real-world Drive Emissions (RDE) methodology is designed to evaluate a vehicle’s emissions under actual driving conditions, rather than in a controlled laboratory environment. Zhan noted the application of broader ambient conditions and the 3 Bin “Moving Average Window” (MAW) method for categorising emissions performance. The 3-Bin method, a classification system used to categorise the severity of vehicle emissions based on their performance during testing, would include a cold-start bin, a low-load bin, and a mid-to-high-load bin. This method involves dividing the emission data into moving average windows to analyse the results more accurately. It is commonly used in regulations such as China VI and Euro VI to assess the compliance of vehicle emissions. The MAW method helps in calculating emissions like CO, CO₂, NOx, and PN more effectively by considering different driving behaviours and conditions.

China 7 will also include a diesel aftertreatment system ageing protocol, similar to the protocol used in U.S. EPA standards, to ensure that laboratory ageing reflects in-field durability performance. A new test protocol will assess fuel sulphur content, engine oil chemical composition and volatility, and oil consumption rates equivalent to the vehicle’s full useful life, says Zhan. The test will employ an accelerated laboratory ageing period of more than 1,000 hours.

Challenges and opportunities

Zhan highlighted the challenges of adopting engine technologies that can simultaneously reduce NOx and CO₂ emissions, avoiding trade-offs between pollutant and CO₂ emissions. Developing technologies to support OBM and OBD, improving aftertreatment and control systems, and addressing cold-start performance and durability are essential.

Global context and future outlook

In April 2024, the European Council adopted the Euro 7 regulation, setting new rules for exhaust emissions from road vehicles, which include regulations for tyre abrasion, brake particle emissions, and battery durability requirements. These new standards will take effect in July 2025 for light-duty cars and 2027 for heavy-duty vehicles.

China 7 standards present opportunities for international suppliers of engine and vehicle technology, fuel, and oil companies to showcase innovations that meet future regulatory demands. These developments highlight China’s commitment to reducing emissions and promoting sustainable transportation, setting a new benchmark for global emissions standards.