Real-road NOx and CO2 emissions of city and highway China-6 heavy-duty diesel vehicles

• Published in: Journal of environmental sciences (China) 2025-03, Vol.149, p.330-341
• Main Authors: Ge, Zihao, Li, Wanyang, Wang, Junfang, Wang, Yachao, Huang, Ying, Wang, Xin, Ge, Yunshan
• Format: Article
• Language: English
• Subjects: CO2 emission; Heavy-duty vehicles; NOx emission; On-Board diagnostics; Remote monitor
• ISSN: 1001-0742
• DOI: 10.1016/j.jes.2023.11.018

The emission of heavy-duty vehicles has raised great concerns worldwide. The complex working and loading conditions, which may differ a lot from PEMS tests, raised new challenges to the supervision and control of emissions, especially during real-world applications. On-board diagnostics (OBD) technology with data exchange enabled and strengthened the monitoring of emissions from a large number of heavy-duty diesel vehicles. This paper presents an analysis of the OBD data collected from more than 800 city and highway heavy-duty vehicles in China using remote OBD data terminals. Real-world NOx and CO2 emissions of China-6 heavy-duty vehicles have been examined. The results showed that city heavy-duty vehicles had higher NOx emission levels, which was mostly due to longer time of low SCR temperatures below 180°C. The application of novel methods based on 3B-MAW also found that heavy-duty diesel vehicles tended to have high NOx emissions at idle. Also, little difference had been found in work-based CO2 emissions, and this may be due to no major difference were found in occupancies of hot running.