A Study on Soot and Ash Accumulation Characteristics of Diesel Particulate Filter Substrate Using Nondestructive Computed Radiography X-ray Imaging Technique

Abstract

The diesel particulate filter of a diesel engine is an after-treatment device that removes particulate matter from exhaust emissions by filtering and oxidating them through a regeneration process. When the diesel particulate filter is damaged, a vehicle inspection is usually performed; if the cause is not found through using on-board diagnostics, then the diesel particulate filter is removed, and a visual test is conducted. However, it is not easy to find the exact cause of the diesel particulate filter being damaged, and a visual test takes a long time as the diesel particulate filter substrate is covered by a canister. In this study, using the computed radiography X-ray imaging technique, X-ray images were taken after placing an accumulated amount of carbon powder, similar to soot and ash powder in the substrate. Results confirmed that carbon powder and ash powder were shown in white in X-ray images, leading to a conclusion that distinguishing between carbon powder and ash powder is possible by analyzing the pixel value through the image processing technique. However, since pixel values alone are insufficient for exact quantitative evaluation, various studies and analyses are necessary for quantitative evaluation.