基于实测的生物柴油农业机械碳质组分排放特征

Biodiesel is recognized as a carbon-neutral fuel, yet its impact on the emissions of key carbonaceous components from diesel engine exhaust remains unclear. To investigate the influence of biodiesel on carbonaceous component emissions from agricultural machinery, this study conducted real-world measurements to systematically analyse the effects of multiple factors-including biodiesel blend ratio (B0, B5, B20), emission standard (China II, China III), machinery type, and operating conditions-on the chemical composition of organic carbon (OC) and elemental carbon (EC) (divided by thermal stability into OC1-OC4 and EC1-EC3). The results indicated that: (1) The emission factors of OC and EC (EF_OC and EF_EC) were significantly reduced by biodiesel blending. For instance, EF_OC and EF_EC were reduced by 44.6% and 24.3%, respectively, for B20compared to B0, which was primarily attributed to increased fuel oxygen content and improved combustion efficiency. (2) The formation of OC and EC subcomponents was jointly influenced by fuel properties and combustion temperature. In emissions from B5machinery, the proportions of OC1 and OC2 were decreased, while that of EC2 was increased. (3) Based on emission factor estimates, the total national OC and EC emissions from agricultural machinery in China in 2022 were calculated to be 10608t and 2507t, respectively, accounting for 27.6% and 9.4% of road mobile source emissions. If B5 and B20 were widely adopted, total OC emissions from agricultural machinery could be reduced by 35.8% and 44.2%, respectively, compared to the B0 baseline.