Experimental evaluation of soot trapping and oxidation behaviors of various diesel particulate filters (DPF) has been traditionally hampered by several experimental difficulties, such as the deposition of soot particles with well-characterized and consistent properties, and the tracking of the soot oxidation rate in real time. In the present study, an integrated bench flow-reactor system with a soot generator has been developed and its capabilities were demonstrated with regards to:
Consistently and controllably loading soot on DPF samples;
Monitoring the exhaust gas composition by FTIR, including quantification of the soot oxidation rate using CO and CO2;
Measuring soot oxidation characteristics of various DPF samples.
Soot particles were produced from a laminar propane co-flow diffusion flame. The production rate of particulate matter (PM) of the soot generator, which is tunable by adjusting the air to fuel ratio of the propane flame, can be set within a range from tens of mg to 400 mg per hour. Properties of collected soot samples, such as the BET surface area and the oxidation activity, were analyzed.
The capabilities of this reactor were demonstrated by conducting tests to evaluate the soot oxidation activity of three types of cordierite DPF samples with variations in the washcoat, including bare, platinum group metals (PGMs) washcoat and non-PGM washcoat. The non-PGM washcoat shows promising performance on enhancing soot oxidation by oxygen.