Heavy-duty diesel vehicle NOX emissions and fuel consumption: Remote on-board monitoring analysis

On-board monitoring (OBM), a cost-effective technical solution for real driving emission monitoring, is being globally adopted, with remote OBM data transmission for China VI heavy-duty diesel vehicles (HDDVs) being mandated, enabling big data–driven analysis of nitrogen oxide (NO_X) emissions and fuel consumption. Enhancing data preprocessing through time alignment and anomaly removal, this study analyzed 14,570 HDDVs, showing a 78.8 % NO_X reduction in China VI versus China V vehicles. Fuel consumption, however, is primarily influenced by vehicle weight, power rating, and driving conditions, and not emission standards. Both NO_X emissions and fuel consumption increased at low speeds. Lower ambient temperatures minimally affected NO_X emissions and fuel consumption, but increased NO_X outliers. Elevated altitude slightly increased fuel consumption, while its influence on NO_X emissions showed no consistent trend. These findings highlight the value of remote OBM data in understanding real-world NO_X emissions and fuel consumption performance, guiding targeted strategies for in-use compliance.