Entwicklung einer beschleunigten Aschebeladung zur Analyse des Alterungsverhaltens von Ottopartikelfiltern

  • Development of an accelerated ash loading method for the aging behavior analysis of gasoline particulate filters

Sterlepper, Stefan; Pischinger, Stefan (Thesis advisor); Jupke, Andreas (Thesis advisor)

Aachen : RWTH Aachen University (2021, 2022)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2021

Abstract

Within the scope of this work, an accelerated ash loading method is developed to investigate the lifetime behavior of gasoline particulate filters. For this purpose, a burner test bench for thermal catalyst aging is extended by an oil injection system. The oil injection is equipped with a secondary air injection and nozzle attachments of different sizes. This way, the oil injection can represent different droplet sizes of the oil spray, resulting in different ash particle sizes. Following are experiments on the ash loading of gasoline particulate filters (GPF) by means of oil injection into the burner test bench. The results show an initially steeply increasing filtration efficiency with comparatively low backpressure penalty. The observation of the wall ash layer under the scanning electron microscope shows a clear separation of GPF substrate and ash layer. This results in a backpressure advantage for the soot loaded component with the initial ash deposition. Furthermore, an entire exhaust aftertreatment system consisting of a three-way catalysts and a coated GPF in one housing is being investigated. The accelerated ash loading shows a disproportionate but reversible decrease of the measured oxygen storage capacity by masking the active centers. For the GPF, no corresponding effect is observed in parallel. This is attributed to the reduced contact area of ash and catalytic coating. In the emission test, the system does not show any major differences compared to a thermally aged system. It is clear from this that the thermal aging phenomena predominate over chemical and mechanical ones. In experimental use, accelerated ash loading by means of oil injection on the burner test bench proves to be a suitable measure of investigating the service life behavior of gasoline engine exhaust aftertreatment systems. The comparability to the vehicle endurance test reference is proven.

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