Effects of exhaust gas recirculation composition and temperature on microscopic mechanical properties of particles in a diesel engine

To investigate the microscopic mechanical properties of particles in a diesel engine, the particles generated with various exhaust gas compositions and temperatures are analyzed by a particle size analyzer and atomic force microscope. The results show that as the exhaust gas temperature increases, the quantity and mass concentration of core mode particle is insignificant, while the accumulation mode particle increased significantly; in addition the particle agglomeration force gradually increases, the major form of agglomeration force gradually shifts from liquid bridge force to Van der Waals force. Studies on exhaust gas composition show that N-2 in exhaust gas is the main factor leading to the increase of accumulation mode particle; while CO2 in exhaust gas could reduces the quantity and mass concentration of particle emissions by reducing the accumulation mode particle; when N-2 is applied, the particle agglomeration force is primarily assumes the form of the Van der Waals force; when CO2 is applied, the particle agglomeration force primarily assumes the form of a liquid bridge force; increasing N-2 content in the exhaust gas can significantly increase the agglomeration force in particles; the effect of increasing CO2 content in the exhaust gas is reversed. (c) 2018 American Institute of Chemical Engineers Environ Prog, 38:e13037, 2019