Browsing by Author "Vojtíšek-Lom, Michal"
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- ItemComparison of hydrogenated vegetable oil and biodiesel effects on combustion, unregulated and regulated gaseous pollutants and DPF regeneration procedure in a Euro6 car(Elsevier B.V., 2019-12-15) Pechout, Martin; Kotek, Martin; Jindra, Petr; Macoun, David; Hart, Jan; Vojtíšek-Lom, MichalThe effects of traditional biodiesel (fatty acid methyl-esters, FAME) and a hydrotreated vegetable oil (HVO) were comprehensively investigated on a production Euro 6 diesel car, including fuel injection rate and timing, combustion analysis, emissions of regulated and unregulated pollutants, and regeneration of the diesel particle filter. The use of both biofuels is a part of the efforts to reduce emissions of greenhouse gases and health-relevant pollutants and to improve energy security and sustainability. HVO, albeit more expensive, offers benefits relative to FAME in terms of oxidation stability, injector fouling, energy content and cetane number. The car was fitted with an on-board instrumentation and subjected to a range of driving cycles on a chassis dynamometer. The fuel consumption calculated from instantaneous emissions data based on exhaust gas composition measured by an on-board FTIR and calculated exhaust flow matched directly measured fuel consumption within several percent on all fuels; differences in the consumption among the fuels correspond to different heating values. The combustion onset and maximum heat release rate were comparable for diesel and FAME but were advanced on HVO due to its higher cetane number, causing, at times, multiple distinct heat release peaks, suggesting that optimization of fuel injection timing for HVO might be beneficial. Emissions of methane and ammonia were negligible, of N2O were measurable and slightly lower for HVO than for other fuels, of formaldehyde were limited to cold engine accelerations and highest for FAME and negligible for HVO, of NO and NO2 were high on all fuels during all operating conditions except for the type approval test. The results confirm several relative advantages of HVO over RME, with penetration into engine lubricating oil during particle filter regeneration to be further investigated. The effects of HVO lubricity and other long-term effects were not evaluated here.
- ItemInternal Combustion Engines as the Main Source of Ultrafine Particles in Residential Neighborhoods: Field Measurements in the Czech Republic(MDPI, 2015) Štolcpartová, Jitka; Pechout, Martin; Dittrich, Luboš; Mazáč, Martin; Fenkl, Michael; Vrbová, Kristýna; Ondráček, Jakub; Vojtíšek-Lom, MichalUltrafine particles (UFP, diameter < 100 nm) exposure has already been associated with adverse effects on human health. Spatial distribution of UFP is non-uniform; they concentrate in the vicinity of the source, e.g. traffic, because of their short lifespan. This work investigates spatial distribution of UFP in three areas in the Czech Republic with different traffic load: High traffic (Prague neighborhood—Sporilov), commuter road vicinity (Libeznice), and a small city with only local traffic (Celakovice). Size-resolved measurements of particles in the 5–500 nm range were taken with a particle classifier mounted, along with batteries, GPS and other accessories, on a handcart and pushed around the areas, making one-minute or longer stops at places of interest. Concentrations along main roads were elevated in comparison with places farther from the road; this pattern was observed in all sites, while particle number distributions both close and away from main roads had similar patterns. The absence of larger particles, the relative absence of higher concentrations of particles away from the main roads, and similar number distributions suggest that high particle number concentrations cannot be readily attributed to sources other than internal combustion engines in vehicles and mobile machinery (i.e., mowers and construction machines).
- ItemThe genotoxicity of organic extracts from particulate truck emissions produced at various engine operating modes using diesel or biodiesel (B100) fuel: A pilot study(ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2019-10) Novotná, Božena; Sikorová, Jitka; Milcová, Alena; Pechout, Martin; Dittrich, Luboš; Vojtíšek-Lom, Michal; Rossner, Pavel; Brzičová, Táňa; Topinka, JanAn analysis of the toxic effects of emissions should reflect real traffic conditions. The exhaust emissions of particulate matter from diesel engines strongly depend on their operating conditions, with low-speed, low-load "urban creep" conditions, common for truck traffic in heavily congested urban areas, being one of the worst. We aimed to detect the genotoxicity of organic extracts from particulate matter in the exhaust of the diesel engine Zetor 1505 running on diesel and biodiesel (B100) fuels at characteristic modes of extended "urban creep", typical for transit truck traffic in Prague, comparing the first 5 min of idling with extended (20-80 min) idling, full load after idle, "stabilized" full load, and 30% load. The diluted exhaust was sampled with high volume samplers on glass fiber fluorocarbon coated filters. The filters were extracted with dichloromethane and DNA damage was analyzed in A549 cells using comet assay, with the inclusion of formamidopyrimidine DNA glycosylase (FPG) and endonuclease III (ENDOIII) to recognize oxidized DNA bases. The cells were exposed to extractable organic matter (EOM) for 4 and 24 h at non-cytotoxic dose corresponding to 0.001 m(3) of undiluted exhaust gas per ml cell media. At the 4 h exposure interval, all samples from B100 and diesel emissions induced DNA damage. EOM from the extended idle engine mode exerted the strongest genotoxic effect for both fuels. Twenty hours later, the cells exposed to diesel EOM exhibited a further increase of DNA strand breaks compared to the preceding interval. In contrast, DNA damage seemed to be fully repaired in cells treated with EOM derived from biodiesel B100. The preliminary results suggest that (i) diesel emissions are more genotoxic than the emissions from B100, (ii) biodiesel induced DNA lesions are repaired within 24 h.