Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering

First Advisor

Sobiesiak, Andrzej


Direct Injection, GPF, Radio Frequency, Soot




Gasoline Direct Injection (GDI) engines represent a promising technology for facing the more and more stringent limits imposed by emission regulations. However, one of the drawbacks of GDI engines compared to PFI engines is the production of soot. One of the possible solutions to reduce the amount of soot emitted in the atmosphere, among the different existent strategies, is the Gasoline Particulate Filter (GPF). Nowadays, the most common device in cars for monitoring the filter state and trigger the regeneration event is the differential pressure sensor. However, this provides an indirect measure of the soot state of the filter using a predictive model implemented in the Electronic Control Unit (ECU). A valid alternative, in laboratory environment, is represented by the Radio Frequency sensor. The objective of the study is to determine if a correlation exists between the output of the RF sensor and the amount of soot in the filter. The final outcome will be an analytical model that uses the average forward gain recorded from the Radio Frequency sensor and the exhaust gas temperature that can be used to estimate the amount of soot on the filter during both loading and regeneration phases. Moreover, with the output of the model during the regeneration event, it will be possible to understand when the soot oxidation starts and to distinguish the different soot reactivity, i.e. how it differently oxidizes during regeneration.