The Effect of Pore Structure on Thermal Characteristics of a Cordierite Diesel Particulate Filter for Heavy Duty Diesel Vehicle

Abstract

As emissions regulations are tightened, various engine and emission reduction improvements have been applied. The reduction of particulate matter (PM), a major diesel engine emission, relies solely on after-treatment in the diesel particulate filter (DPF). It is not possible to satisfy current exhaust regulations without a DPF installed downstream of a diesel engine. Therefore, in the design of DPF systems, thermal stability and durability at the high temperatures experienced during the regeneration process are considered critical in determining the substrate material, as any defects (cracking, damage, or melting) cause increased pollutant emissions. In this study, the regeneration characteristics of 10.5 in cordierite DPF substrates applied in large commercial vehicles were investigated according to pore structure. The pore structure was changed while maintaining the thermal expansion coefficient and thermal properties by changing the particle size of talc during fabrication. Two different substrate compositions were evaluated and applied in a 6-L diesel engine to analyze their thermal characteristics during normal and uncontrolled (drop-to-idle) regeneration according to PM loading. The improvement in pore structure was observed to increase the PM oxidation rate under normal regeneration and extended the PM loading limit under uncontrolled regeneration.