Gasoline Particulate Filter Characterization Focusing on the Filtration Efficiency of Nano-Particulates Down to 10 nm

Dorscheidt, Frank; Sterlepper, Stefan; Görgen, Michael; Nijs, Martin; Claßen, Johannes; Yadla, Surya Kiran; Maurer, Robert; Pischinger, Stefan; Krysmon, Sascha; Abdelkader, Abdelrahman

doi:10.4271/2020-01-2212

Cited by 19 publications

(9 citation statements)

References 32 publications

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“…However, none of these reasons can adequately explain our results: the cycle was a high-speed cycle with a high flow rate from the beginning, the filter was fresh (new), and the deposited soot should be minimal due to the test cycles and protocol that supported passive regeneration of the filter. In the 23 nm to 50 nm range, high filtration efficiencies are expected [64]. At the sub-23 nm range, in many cases the filtration efficiency can be higher, but not always [64].…”

Section: Discussionmentioning

confidence: 98%

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Challenging Conditions for Gasoline Particulate Filters (GPFs)

et al. 2022

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The emission limit of non-volatile particles (i.e., particles that do not evaporate at 350 °C) with size >23 nm, in combination with the real driving emissions (RDE) regulation in 2017, resulted in the introduction of gasoline particulate filters (GPFs) in all light-duty vehicles with gasoline direct injection engines in Europe. Even though there are studies that have examined the particulate emissions at or beyond the current RDE boundary conditions, there is a lack of studies combining most or all worst cases (i.e., conditions that increase the emissions). In this study, we challenged a fresh (i.e., no accumulation of soot or ash) “advanced” prototype GPF at different temperatures (down to −9 °C), aggressive drive cycles and hard accelerations (beyond the RDE limits), high payload (up to 90%), use of all auxiliaries (air conditioning, heating of the seats and the rear window), and cold starts independently or simultaneously. Under hot engine conditions, the increase of the particulate emissions due to higher payload and lower ambient temperature was 30–90%. The cold start at low ambient temperature, however, had an effect on the emissions of up to a factor of 20 for particles >23 nm or 300 when considering particles <23 nm. We proposed that the reason for these high emissions was the incomplete combustion and the low efficiency of the three-way oxidation catalyst. This resulted in a high concentration of species that were in the gaseous phase at the high temperature of the close-coupled GPF and thus could not be filtered by the GPF. As the exhaust gas cooled down, these precursor species formed particles that could not be evaporated at 350 °C (the temperature of the particle number system). These results highlight the importance of the proper calibration of the engine out emissions at all conditions, even when a GPF is installed.

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Section: Discussionmentioning

confidence: 98%

“…In the 23 nm to 50 nm range, high filtration efficiencies are expected [64]. At the sub-23 nm range, in many cases the filtration efficiency can be higher, but not always [64]. During cold start, the temperature at the three-way catalyst (TWC) and the GPF was also relatively low (it reached 700 • C after the first minute).…”

Section: Discussionmentioning

confidence: 99%

Challenging Conditions for Gasoline Particulate Filters (GPFs)

et al. 2022

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“…Comparing the size distributions curves presented by Giechaskiel et al [30] and Tabata et al [41] versus the results documented by Badshah et al [42] and the results from Figures 4 and 5, it can be concluded that soot properties for soot obtained during warm engine operation versus cold-start soot differs strongly in terms of their size distribution. As explained by, e.g., Dorscheidt et al [12], the size distribution of the soot could have a significant effect on the penetration depth of the particulates into the filter wall and on the ratio deep-bed versus soot cake filtration depending on the soot load, hence on the backpressure behaviour of the respective component. Therefore, being able to reproduce comparable size distribution curves is one elementary prerequisite to shifting GPF calibration activities to the burner test bench.…”

Section: Discussionmentioning

confidence: 99%

“…This is due to the abundance of medical research that indicates the adverse health effects of ultrafine aerosol particles [9][10][11]. Several investigations indicate that neglecting sub-23 nm particulates during the development process could lead to significant additional efforts to comply with future Euro 7 emission limits [12][13][14][15]. Ultimately, the end goal is having an internal combustion engine with zero tailpipe pollutant emissions, such as the study presented by Thewes et al [16].…”

Section: Introductionmentioning

confidence: 99%

Development of a Novel Gasoline Particulate Filter Loading Method Using a Burner Bench

et al. 2021

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In view of the deliberations on new Euro 7 emission standards to be introduced by 2025, original equipment manufacturers (OEMs) are already hard at work to further minimise the pollutant emissions of their vehicles. A particular challenge in this context will be compliance with new particulate number (PN) limits. It is expected that these will be tightened significantly, especially by including particulates down to 10 nm. This will lead to a substantially increased effort in the calibration of gasoline particulate filter (GPF) control systems. Therefore, it is of great interest to implement advanced methods that enable shortened and at the same time more accurate GPF calibration techniques. In this context, this study presents an innovative GPF calibration procedure that can enable a uniquely efficient development process. In doing so, some calibration work packages involving GPF soot loading and regeneration are transferred to a modern burner test bench. This approach can minimise the costly and time-consuming use of engine test benches for GPF calibration tasks. Accurate characterisation of the particulate emissions produced after a cold start by the target engine in terms of size distribution, morphology, and the following exhaust gas backpressure and burn-off rates of the soot inside the GPF provides the basis for a precise reproduction and validation process on the burner test bench. The burner test bench presented enables the generation of particulates with a geometric mean diameter (GMD) of 35 nm, exactly as they were measured in the exhaust gas of the engine. The elemental composition of the burner particulates also shows strong similarities to the particulates produced by the gasoline engine, which is further confirmed by matching burn-off rates. Furthermore, the exhaust backpressure behaviour can accurately be reproduced over the entire loading range of the GPF. By shifting GPF-related calibration tasks to the burner test bench, total filter loading times can be reduced by up to 93%.

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“…The contribution of direct and indirect vehicle emissions to air pollution and increasing greenhouse gases (GHG) in the atmosphere has led to increasingly stringent emission standards being imposed by legislators worldwide. In addition, emission limits are being added for previously unlimited exhaust components [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Real Driving Emissions—Conception of a Data-Driven Calibration Methodology for Hybrid Powertrains Combining Statistical Analysis and Virtual Calibration Platforms

et al. 2021

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The combination of different propulsion and energy storage systems for hybrid vehicles is changing the focus in the field of powertrain calibration. Shorter time-to-market as well as stricter legal requirements regarding the validation of Real Driving Emissions (RDE) require the adaptation of current procedures and the implementation of new technologies in the powertrain development process. In order to achieve highest efficiencies and lowest pollutant emissions at the same time, the layout and calibration of the control strategies for the powertrain and the exhaust gas aftertreatment system must be precisely matched. An optimal operating strategy must take into account possible trade-offs in fuel consumption and emission levels, both under highly dynamic engine operation and under extended environmental operating conditions. To achieve this with a high degree of statistical certainty, the combination of advanced methods and the use of virtual test benches offers significant potential. An approach for such a combination is presented in this paper. Together with a Hardware-in-the-Loop (HiL) test bench, the novel methodology enables a targeted calibration process, specifically designed to address calibration challenges of hybridized powertrains. Virtual tests executed on a HiL test bench are used to efficiently generate data characterizing the behavior of the system under various conditions with a statistically based evaluation identifying white spots in measurement data, used for calibration and emission validation. In addition, critical sequences are identified in terms of emission intensity, fuel consumption or component conditions. Dedicated test scenarios are generated and applied on the HiL test bench, which take into account the state of the system and are adjusted depending on it. The example of one emission calibration use case is used to illustrate the benefits of using a HiL platform, which achieves approximately 20% reduction in calibration time by only showing differences of less than 2% for fuel consumption and emission levels compared to real vehicle tests.

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Gasoline Particulate Filter Characterization Focusing on the Filtration Efficiency of Nano-Particulates Down to 10 nm

Cited by 19 publications

References 32 publications

Challenging Conditions for Gasoline Particulate Filters (GPFs)

Challenging Conditions for Gasoline Particulate Filters (GPFs)

Development of a Novel Gasoline Particulate Filter Loading Method Using a Burner Bench

Real Driving Emissions—Conception of a Data-Driven Calibration Methodology for Hybrid Powertrains Combining Statistical Analysis and Virtual Calibration Platforms

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