Browsing by Author "Dittrich, Luboš"

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    Analýza podmínek vzniku emisí a možnosti jejich snížení u stacionárních spalovacích motorů
    (2020-3-10) Dittrich, Luboš; ; Moc Lubomír, doc. Ing. CSc. Skolitel : 55346
    Práce je zaměřena na experimentální výzkum a analýzu pracovního oběhu a výfukových emisí pístového spalovacího motoru v režimech nízkého zatížení, které představují výzvu pro ve vyšších zatíženích vysoce účinná zařízení pro úpravu výfukových plynů. Pro měření bylo sestaveno laboratorní stanoviště se zkušebním jednoválcovým motorem. Běhen stavby zařízení bylo testováno několik variant řízení motoru. Dokončené stanoviště sloužilo pro měření emisí a významných provozních veličin. Měření bylo provedeno ve třech variantách. Výchozím bylo měření neupraveného motoru v klasickém zážehovém režimu. Následovalo doplnění spalovacího prostoru o komůrku a jako poslední byl měřen režim nízkoteplotního spalování. Tato měření byla následně vyhodnocena a popsána. Vlastní přínosy práce zahrnují kromě konstrukčních řešení a zvládnutí experimentálně náročného provozu motoru v režimu řízené detonace také několik unikátních řešení částí experimentální aparatury, která našla praktické využití v dalších projektech výzkumu a vývoje.
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    Internal Combustion Engines as the Main Source of Ultrafine Particles in Residential Neighborhoods: Field Measurements in the Czech Republic
    (MDPI, 2015-01-01) Štolcpartová, Jitka; Pechout, Martin; Dittrich, Luboš; Mazáč, Martin; Fenkl, Michael; Vrbová, Kristýna; Ondráček, Jakub; Vojtíšek-Lom, Michal
    Ultrafine 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).
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    The 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, 2019-10-01) Novotná, Božena; Sikorová, Jitka; Milcová, Alena; Pechout, Martin; Dittrich, Luboš; Vojtíšek-Lom, Michal; Rossner, Pavel; Brzičová, Táňa; Topinka, Jan
    An 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.
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    Universální stojan pro převodovky osobních automobilů
    (2008-01-01) Dittrich, Luboš
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    Univerzální stojan pro převodovky OA
    (Technická Univerzita v Liberci, 2008-01-01) Dittrich, Luboš; Tomeh, Elias
    The aim of this work is to design an universal frame of the gearbox. The work includes the survey of the current market with variety of the frames and gearboxes used in automobile industry. Furthermore, the project is interested in summary of current status of equipment at the laboratory of engines and vehicles at Technical University of Liberec. Finally, the work provides individual proposal and design of the construction of the frame connected with calculations. The part of the work is also drawing documentation and the frame itself (the product) Key words: Universal t). stand, gearbox, laboratories
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    Vznětový motor na dimetyleter (DME)
    (Technická Univerzita v Liberci, 2012-01-01) Dittrich, Luboš; Laurin, Josef
    In this thesis the basic properties of dimethylether (DME) are described. It is possible to use DME as an alternative fuel for compression ignition engines. The parameters of current engines fuelled by DME are also described. The main objective of this work is to create a reconstruction of a city bus for a DME use and to rebuild a fuel system for DME. The last part of the work is also drawing documentation.
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    Vznětový motor na dimetyleter (DME)
    (2012-01-01) Dittrich, Luboš