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Author

Rasto Brezny

Bio: Rasto Brezny is an academic researcher. The author has contributed to research in topics: Particulates & Gasoline direct injection. The author has an hindex of 4, co-authored 5 publications receiving 97 citations.

Papers
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Journal ArticleDOI
TL;DR: The results showed dramatic reductions in particulate matter (PM) mass, black carbon, and total and solid particle number emissions with the use of GPFs for both vehicles over the LA92 and US06 cycles.
Abstract: We assessed the gaseous, particulate, and genotoxic pollutants from two current technology gasoline direct injection vehicles when tested in their original configuration and with a catalyzed gasoline particulate filter (GPF). Testing was conducted over the LA92 and US06 Supplemental Federal Test Procedure (US06) driving cycles on typical California E10 fuel. The use of a GPF did not show any fuel economy and carbon dioxide (CO2) emission penalties, while the emissions of total hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx) were generally reduced. Our results showed dramatic reductions in particulate matter (PM) mass, black carbon, and total and solid particle number emissions with the use of GPFs for both vehicles over the LA92 and US06 cycles. Particle size distributions were primarily bimodal in nature, with accumulation mode particles dominating the distribution profile and their concentrations being higher during the cold-start period of the cycle. Polycyclic aromatic hydrocarbons...

53 citations

Journal ArticleDOI
TL;DR: The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis.
Abstract: The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, that is, the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions. The mean projected area-equivalent diameter of these aggregates is in the 78.4–88.4 nm range and the mean diameter of primary particles varies between 24.6 and 26.6 nm. Post-GPF particles emitted over the US06 cycle appear to have an amorphous structure, and a large number of nucleation-mode particles, depicted as low-contrast ultrafine droplets, are observed in TEM images. This indi...

47 citations

Journal ArticleDOI
TL;DR: The results showed strong reductions in particulate mass (PM), soot mass, and particle number emissions with the use of GPFs, and nitrogen oxide (NOx) emissions showed improvements with the catalyzed GPFs in the underfloor position with the additional catalytic volume.

36 citations

Journal ArticleDOI
TL;DR: It was found that the addition of catalyzed GPFs will significantly reduce tailpipe particulate emissions and also provide benefits in gaseous emissions, including nonmethane hydrocarbons (NMHC).
Abstract: The effects of photochemical aging on exhaust emissions from two light-duty vehicles with gasoline direct injection (GDI) engines equipped with and without catalyzed gasoline particle filters (GPFs) were investigated using a mobile environmental chamber. Both vehicles with and without the GPFs were exercised over the LA92 drive cycle using a chassis dynamometer. Diluted exhaust emissions from the entire LA92 cycle were introduced to the mobile chamber and subsequently photochemically reacted. It was found that the addition of catalyzed GPFs will significantly reduce tailpipe particulate emissions and also provide benefits in gaseous emissions, including nonmethane hydrocarbons (NMHC). Tailpipe emissions composition showed important changes with the use of GPFs by practically eliminating black carbon and increasing the fractional contribution of organic mass. Production of secondary organic aerosol (SOA) was reduced with GPF addition, but was also dependent on engine design which determined the amount of SOA precursors at the tailpipe. Our findings indicate that SOA production from GDI vehicles will be reduced with the application of catalyzed GPFs through the mitigation of reactive hydrocarbon precursors.

13 citations

Journal ArticleDOI
TL;DR: In this paper, a large collection of on-road commercial vehicle operating data is analyzed to identify start-up events and inspect associated emissions, and it is shown that vehicle behavior, in terms of engine cold-and warm-operation, starts per day, soak time, and warm-up duration, differs significantly between vehicle vocations.
Abstract: Diesel engines produce disproportionate levels of emissions when the engine and after-treatment systems are operating at low temperatures. This situation arises most commonly when the vehicle is first started after overnight. To quantify emissions attributable to vehicle starts, a sizable collection of on-road commercial vehicle operating data is analyzed to identify start-up events and inspect associated emissions. Data was obtained from the National Renewable Energy Laboratory’s (NREL’s) Fleet DNA and from the Center for Environmental Research & Technology (CE-CERT). Included are 500 + diesel vehicles with more than 42,000 recorded days, drawn from 25 vocational categories across the United States. Analysis shows that vehicle behavior, in terms of engine cold- and warm-operation, starts per day, soak time, and warm-up duration, differs significantly between vehicle vocations. Also, weighting factors for cold- and hot-starts currently used in the U.S. Environmental Protection Agency’s Federal Test Procedure (FTP) for heavy-duty emissions certification accurately represent real-world operations. Although the FTP includes a comparable fraction of cold operation, the hot fraction is much shorter than real-world operation due to limited test duration. The investigation also revealed that real-world engines operate for a significant amount of time when the engine coolant is in the “hot-stabilized” region, but the selective catalytic reduction (SCR) temperature is below its effective operating temperature of 200 °C. Of the vehicles under investigation, almost 20% of their operational time is within this condition. Thus, novel approaches to raise and maintain SCR temperature are highly required to further reduce engine emissions.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the potential of fuel candidates to increase efficiency in spark-ignition (SI) engines is quantified in a way that allows the individual fuel properties to be traded off for one another.

109 citations

Journal ArticleDOI
Yong Qian1, Zilong Li1, Liang Yu1, Xiaole Wang1, Xingcai Lu1 
TL;DR: In this article, a comprehensive review on the latest research progress, including the particulate matter formation mechanism of gasoline engines, effects of fuel/air mixture preparation strategies, fuel physical-chemical properties, and engine operating conditions on particulate size distribution characteristics, and the effects of the driving cycle on vehicle particulate emissions were summarized.

108 citations

Journal ArticleDOI
TL;DR: Fossil fuels are likely to continue to be the major source of on-road vehicle energy consumption and fuel economy and emission standards are generally effective in achieving reductions per unit of vehicle activity, however, the number of vehicles and miles traveled will increase.
Abstract: Globally, 1.3 billion on-road vehicles consume 79 quadrillion BTU of energy, mostly gasoline and diesel fuels, emit 5.7 gigatonnes of CO2, and emit other pollutants to which approximately 2...

83 citations

Journal ArticleDOI
TL;DR: In this paper, a review summarizes the evolution of PM mass emissions from gasoline vehicles placed in the market from early 1990s until 2019 in different parts of the world, and the analysis then extends to total and nonvolatile particle number emissions.
Abstract: The particulate matter (PM) emissions of gasoline vehicles were much lower than those of diesel vehicles until the introduction of diesel particulate filters (DPFs) in the early 2000s. At the same time, gasoline direct injection (GDI) engines started to become popular in the market due to their improved efficiency over port fuel injection (PFI) ones. However, the PM mass and number emissions of GDI vehicles were higher than their PFI counterparts and diesel ones equipped with DPFs. Stringent PM mass levels and the introduction of particle number limits for GDI vehicles in the European Union (EU) resulted in significant PM reductions. The EU requirement to fulfill the proposed limits on the road resulted to the introduction of gasoline particulate filters (GPFs) in EU GDI models. This review summarizes the evolution of PM mass emissions from gasoline vehicles placed in the market from early 1990s until 2019 in different parts of the world. The analysis then extends to total and nonvolatile particle number emissions. Care is given to reveal the impact of ambient temperature on emission levels. The discussion tries to provide scientific input to the following policy-relevant questions. Whether particle number limits should be extended to gasoline PFI vehicles, whether the lower limit of 23 nm for particle number measurements should be decreased to 10 nm, and whether low ambient temperature tests for PM should be included.

77 citations

Journal ArticleDOI
05 Nov 2018
TL;DR: In this article, a review summarizes representative studies on particulate emissions from gasoline engines, the nature of the particulates, and the advances in GPF technology, and it is anticipated that gasoline particulate filters (GPFs) will be widely applied to gasoline exhaust aftertreatment.
Abstract: To improve ambient air quality, several countries have adopted regulations setting stringent limits on vehicular tailpipe emissions of particulates. The issue of high particulate emissions has been mostly addressed for diesel vehicles with the widespread adoption of diesel particulate filters (DPFs). Attention is now turned to gasoline direct injection (GDI) technology, which provides improved fuel economy and performance, but also increased particulate emissions, as compared to the port fuel injection (PFI) engines. Europe has set a particle number (PN) limit on emissions from GDI vehicles, while China has expanded that to include all gasoline vehicles. In the USA, these are regulated through particle mass (PM) limits. To meet these regulations, it is anticipated that gasoline particulate filters (GPFs) will be widely applied to gasoline exhaust after-treatment. GPF technology has rapidly advanced, and already a wide range of pore size distribution and cell geometries are being offered to minimize back pressure and offer high ash storage capacity, high filtration efficiency, and, in the case of filters combined with three-way catalytic functionality, high conversion of gas-phase criteria pollutants. This review summarizes representative studies on particulate emissions from gasoline engines, the nature of the particulates, and the advances in GPF technology.

56 citations