X-ray Microscopy of Particulate Matter in Automotive Filters

  • Matthew Jones

Student thesis: Phd


It is important to develop technologies for clean and fuel efficient combustion engines. Particulate filters mitigate Particulate Matter (PM) pollution by filtering PM from exhaust gas. Over the operational lifetime of a particulate filter, PM, such as soot and ash, will build up on filter surfaces and in filter pores. These effect performance in myriad ways. In this project we develop quantitative X-ray microscopy techniques for the study of these processes. During this project we imaged particulate deposits in automotive filters using time lapse X-ray Computed Tomography (XCT), X-ray Ptychotomography (XPT) and other methods. Time lapse XCT was used to resolve deposits as they built up in the pores and surfaces of the filter overtime. This required building a bespoke aerosol flow rig and data processing pipeline. From this method we were able to extract useful quantitative data about the filtration. For example, we were able to plot the channel scale deposition profiles of soot-like nanopowder deposited in the deep bed and on the wall of a particulate filter. In the future this method could be used to validate models of soot filtration in particulate filters. In this project we also demonstrate XPT as a high resolution 3D non-destructive imaging technique for the study of ash. This allows us to make new insights into the micro-structure and evolution of automotive ash, which has an important effect on the in-use performance of these filters. For example, we were able to quantify the internal porosity of ash particles and found a positive correlation between particle size and internal porosity.
Date of Award31 Dec 2023
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorSarah Haigh (Supervisor), David Eastwood (Supervisor) & Chris Hardacre (Supervisor)


  • X-ray Computed Tomography
  • Particulate Filters
  • Tomography
  • Aerosol

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