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Increasingly stringent vehicle emissions legislation is being introduced throughout the world, regulating the allowed levels of particulate matter emitted from vehicle tailpipes. The regulation may prove challenging for gasoline vehicles equipped with modern gasoline direct injection (GDI) technology, owing to their increased levels of particulate matter production. It is expected that gasoline particulate filters (GPFs) will soon be fitted to most vehicles sold in China and Europe, allowing for carbonaceous particulate matter to be effectively captured. However, GPFs will also capture and accumulate non-combustible inorganic ash within them, mainly derived from engine oil. Studies exist to demonstrate the impact of such ash on GPF and vehicle performance, but these commonly make use of accelerated ash loading methods, which themselves introduce significant variation.

Engine laboratory tests were conducted to assess the impact of B20 biodiesel on the performance of cordierite diesel particulate filters (DPFs). Test fuels included 20% soy based methyl ester blended into ultra low sulfur diesel fuel, and two ULSD on-road market fuels. B20 has a higher cetane number, boiling point and oxygen content than typical on-road diesel fuels. A comparative study was performed using a model year 2007 medium duty diesel truck engine. The aftertreatment system included a diesel oxidation catalyst (DOC) followed by a cordierite wall flow DPF. A laboratory-grade supplemental fuel doser was used in the exhaust stream for precise regeneration of the DPF. Tests revealed that the fuel dosing rate was higher and DOC fuel conversion efficiency was poorer for the B20 fuel during low exhaust temperature regenerations. The slip of B20 fuel past the DOC was shown to produce significantly higher exotherms in the DPF during regeneration.

With the introduction of a stringent particulate number (PN) limit and real driving emission (RDE) requirements, gasoline particulate filters (GPF) are widely adopted for gasoline engines in Europe and China. The filter collects soot and ash. Like in diesel applications, the collected soot will continuously burn under favorable exhaust conditions. However, at extreme conditions, there could be large amounts of soot build-up, which may induce a highly exothermal event, potentially damaging the filter. Thus, it is important to understand what drives the over-heating in application, and develop counter measures. In this study, an on-vehicle fuel cut (FC) testing procedure was developed. The testing was conducted on two vehicles, one gasoline direct injection (GDI) vehicle and one multiple port injection (MPI) vehicle, with different exhaust systems designs (a close coupled GPF and an under floor GPF) and catalyst coating levels (bare and heavily coated GPFs).