Data-driven method for estimating emission factors of multiple pollutants from excavators based on portable emission measurement system and online driving characteristic identification.

This study aims to explore the factors that influence the emission characteristics of multiple pollutants from non-road mobile machinery (NRMM) under real-world conditions and to establish a data-driven method for calculating accurate emission factors. This research focused on NRMM excavators meeting the third-stage emission standards and identified the actual work characteristics of 108 excavators in different scenarios based on a self-developed testing system for 368,000 h. Additionally, a portable emission testing system (PEMS) was used to study the instantaneous emission characteristics under different driving styles and modes for 10 EC210 excavators with the largest engineering construction inventory.

Impact of Individual Cell Parameter Difference on the Performance of Series-Parallel Battery Packs.

Lithium-ion power batteries are used in groups of series-parallel configurations. There are Ohmic resistance discrepancies, capacity disparities, and polarization differences between individual cells during discharge, preventing a single cell from reaching the lower limit of the terminal voltage simultaneously, resulting in low capacity and energy utilization. The effect of the parameter difference (difference in parameters) of individual cells on the performance of the series-parallel battery pack is simulated and analyzed by grouping cells with different parameters.

Emission characteristics of particulate matter emitted by typical off-road construction machinery.

Off-road machinery, especially construction equipment, is one of the most important pollutant sources of the deterioration in the air quality of Chinese urban areas owing to its large quantity and to the absence of stringent emission requirements. In this study, we used a portable emission measurement system (PEMS) to measure the exhaust pollutant emission characteristics for 13 pieces of construction machinery including excavators and hydraulic crushers under different working conditions, such as real-world operating condition, free accelerating condition, and overloading condition, innovatively adopting the method of synchronizing video recording and emission measurement to divide the operation process of construction machinery under different working conditions into different action stages. In addition, the relationship between the emission characteristics and the maintenance history of 13 pieces of construction machinery was analyzed.