Nondestructive X-ray Inspection of Thermal Damage, Soot and Ash Distributions in Diesel Particulate Filters

We describe novel results of ongoing research at 3DX-RAY Ltd and Oak Ridge National Laboratory using new, commercially available, nondestructive x-ray techniques to make engineering measurements of diesel particulate filters (DPF). Nondestructive x-ray imaging and data-analysis techniques were developed to detect and visualize the small density changes corresponding to the addition of substances such as soot and ash to DPF monoliths. The usefulness of this technique was explored through the analysis of field-aged samples, accelerated-aged samples, and the synthetic addition of ash and soot to clean DPF samples. We demonstrate the ability to visualize and measure flaws in substrates and quantify the distribution of ash and soot within the DPF. We also show that the technology is sensitive enough for evaluations of soot and ash distribution and thermal damage without removing the DPF from its metal casing.