A diesel particulate filter (DPF) is an after-treatment device designed to capture and store exhaust particulate matter emitted by diesel vehicles. DPFs are damaged owing to complex reasons, such as regeneration processes and loads generated during driving. While DPFs can be damaged, they can also be manipulated, especially DPFs with hollow damage. In such cases, the filtration performance deteriorates significantly, and excessive amounts of smoke and ash are emitted during driving, resulting in environmental pollution. In this study, DPF damage types were observed using the CR X-ray imaging technique without removing the DPF. In addition, it was experimentally determined that the five types of DPF shapes (normal, crack, melt, plug, and hollow) caused increases in the particle number (PN) and smoke concentration. Experiments were conducted in the Korea Diesel 147 (KD-147) vehicle driving mode, and the PN and smoke concentration were measured using a nanoparticle emission tester 3795 (NPET-3795-HC) and opacimeter (OPA-102). The experiment was conducted 10 times for each type of DPF damage. As a result of the experiment, no significant difference was found between the normal DPF and crack-damaged DPF in terms of smoke emission, but there was a definite difference in the smoke concentration relative to the other DPF damage types. DPF of all damage types satisfied Korea's smoke concentration regulation. In addition, the PN emission characteristics differed clearly in terms of the values measured for each damage type, and, unlike the smoke concentration characteristics, there was a clear difference in the PN emission characteristics of various DPF damage types. In addition, the PN concentration tended to increase in the rapid acceleration section of the KD-147 vehicle driving mode for all DPF damage types.
