This article discusses the possibilities of powering a commonly used diesel engine with renewable fuels. It analyses scientific studies that clearly indicate that the use of hydrogen is a potentially future-proof option due to its potential to reduce specific fuel consumption and improve performance and increase thermal efficiency. The research was carried out on a laboratory bench designed to test a diesel engine fueled by different fuels. A proprietary hydrogen injection system with dedicated control software was used. Hydrogen injection pressures of 0.15, 0.18, 0.20 MPa and hydrogen injector opening times of 2.5, 3.0, 3.5 ms, respectively, were set as control parameters. The rapidly varying engine operating parameters were recorded and the parameters calculated from them were analysed.
The article discusses one of the most popular methods of diagnosing selected damages of marine piston engines, which is the indication or measurement of pressure changes in the engine’s combustion chamber. Improving the quality of indicator diagrams may contribute to the increase in the efficiency of using the parameters indicated in the diagnostics of marine piston engines. Measurement errors during engine indication are primarily caused by measuring channels that connect the combustion chamber to the pressure sensor. One way to avoid these errors is to install the pressure sensor directly in the combustion chamber. It seems that it is possible to eliminate these errors. However, there is a risk that the pressure sensor will be damaged by the effect of high temperature on it during combustion of the fuel-air mixture in the engine’s combustion chamber. The article presents the results of tests that indicate that the measured temperatures in the place where the sensor was installed (in the combustion chamber) did not exceed the critical value specified by the pressure sensor manufacturer. The article also presents the results of cylinder pressure measurement not only in the combustion chamber but also in two other points - on the thread of the indicator cock and in the measuring channel between the indicator cock and the cylinder head. The tests were carried out in a wide range of engine load technically efficient and with simulated damage in the fuel injection system. The article presents a comparative analysis of the parameters read out of the indicator diagram for the three abovementioned pressure measurement locations. It was shown that the pressure measurements carried out directly in the combustion chamber are free from errors resulting from the influence of measuring channels and indicator cock.
Artykuł przedstawia wybrane problemy analizy przebiegów ciśnień cylindrowych w okrętowych silnikach tłokowych. Prawidłowo sporządzony i przeanalizowany wykres indykatorowy pomaga w formułowaniu wniosków diagnostycznych, za pomocą których można doprowadzić do optymalnej, pod kątem ekonomicznym i ekologicznym, regulacji silnika okrętowego. Pomiary ciśnień cylindrowych zaliczane są do trudnych, a także obarczonych wieloma błędami, dlatego też głównym tematem artykułu jest przedstawienie nowej koncepcji pomiarów przebiegów ciśnień cylindrowych.
EN
The article presents selected problems regarding the correct analysis of cylinder pressures in ship piston engines. Correctly prepared and the analyzed indicator diagram helps in formulating appropriate diagnostic conclusions, with the help of which it is possible to achieve the optimal, in economic and environmental terms, regulation of the ship's engine. Cylinder pressure measurements are classified as difficult and also burdened with many errors. Therefore, the main topic of the article is to present a new concept for cylinder pressure measurements.
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The study aims at evaluating whether webs reflect the level of air pollution measured with conventional methods. Webs of species Malthonica silvestris (l. KOCH, 1872) (Araneae: Agelenidae) were sampled. Samples were analyzed for heavy metals (Pb, Zn) content. According webs analyses and classic measurements three traffic-oriented sites in Wroclaw (South-West Poland) showed significantly higher mean concentrations of heavy metals than two other sites situated in quieter, low traffic areas. A very strong significant positive correlation was revealed among average concentrations of Zn and Pb associated with fine particulate matter of atmospheric aerosol (PM1) and webs. We also observed a very strong significant positive correlation among Zn and Pb concentrations on webs and PM2.5. Any significant correlation among PM-emission fractions 2.5 and 10 and associated heavy metals and dust deposited on spider webs was not observed. Although spider webs proved useful indicators of environmental pollution the obtained results suggest that this tool should be used to evaluate the emission of heavy metals in the similar way as other bioindicators such as mosses and lichens are commonly used. The measured concentrations on webs do not reflect results obtained with classic methods. We conclude that spider webs are good for bioindication of road traffic emissions, they could be even more reliable compared to use of some other bioindicators whose activity is often limited by the lack of water and sun.
PL
Celem badań była ocena efektywności sieci pajęczych jako narzędzia do indykacji zanieczyszczeń komunikacyjnych powietrza atmosferycznego. Wykorzystano sieci gatunku Malthonica silvestris (l. KOCH, 1872) należącego do rodziny Agelenidae. Pajęczyny oceniono pod kątem zawartości dwóch metali ciężkich (ołów i cynk) związanych z emisjami pochodzącymi z komunikacji drogowej. Otrzymane wyniki zestawiono z pomiarami wykonanymi metodami klasycznymi oceny jakości powietrza atmosferycznego (impaktory). Wysokie stężenia obydwu badanych metali odnotowano na trzech stanowiskach badawczych zlokalizowanych w miejscach o wysokim natężeniu ruchu kołowego we Wrocławiu, z kolei na obszarach o mniejszym natężeniu ruchu odnotowano niższe i statystycznie istotne wartości tych metali. Takie same wyniki otrzymano przy zastosowaniu obydwu metod (sieci pajęczych i metody klasycznej). Jednakże, silne pozytywne korelacje obserwowano jedynie w przypadku ołowiu i cynku związanych z frakcją pyłu drobnego PM1 i tych samych metali zidentyfikowanych na sieciach pajęczych. Stwierdzono także silną dodatnią korelację w przypadku stężeń Zn i Pb odnotowanych na sieciach pajęczych i frakcją pyły mierzonego metodą klasyczną PM2.5 (ale nie metalami!). Ponadto, nie zaobserwowano żadnych istotnych statystycznie korelacji między stężaniami metali i frakcjami pyłu mierzonymi obiema metodami. Co więcej, wyniki analizy wariancji wskazują na brak homogeniczności oraz istnienie różnic istotnych statystycznie między stężaniami metali zarejestrowanymi na sieciach i za pomocą metody klasycznej. Jako że stwierdzone korelacje można uznać za przypadkowe, nie rekomenduje się wykorzystania sieci zamiennie z metodą klasyczną oceny jakości powietrza atmosferycznego. Jednakże, tak jak inne bioindykatory, sieci stanowią doskonałe narzędzie do monitoringu powietrza ze względu na łatwość poboru próbek, możliwość oceny zanieczyszczeń długoterminowych, dostępność. Brak zależności od światła i dostępność przez cały rok czyni je narzędziami znacznie bardziej przydatnymi do bioindykacji niż obecnie powszechnie wykorzystywane mchy, rośliny czy porosty.
The results of the research assessing the possibility of using spider webs for the indication of organic pollutants (PAHs) in the long period of time in the air polluted with road traffic emissions are presented. It was proved that webs could be used for the indication of pollutants of this type. Because of the great availability and dense structure of webs belonging to representatives of Agelenidae family, they can serve as a very effective tool. What is more, the secluded location of webs is favorable and influences the accuracy and credibility of results, since deposited pollutants are not washed off with rain, neither are they decomposed by microorganisms or sunlight. The influence of co-existing contaminants is also minimized.
W artykule przedstawiono obecne techniki monitorowania pracy silników i sprężarek dużej mocy. Ze względu na znaczne koszty ewentualnego wyłączenia z ruchu tego typu maszyn są one poddane obserwacji dla przewidywania ewentualnych awarii oraz planowych zatrzymań. Rośnie liczba zaawansowanych systemów pomiarowych z indykowaniem cylindrów. Dawne metody wibroakustyczne zastępowane są pomiarami parametrów procesu termodynamicznego.
EN
This paper presents current techniques for monitoring the performance of engines and compressors power. Due to the significant costs of a possible exemption from the movement of this type of machine they are subjected to observation to predict possible failures and scheduled stops. There is a growing number of advanced metering systems with indykowaniem cylinders. The old methods are replaced vibroacoustic measurements of thermodynamic parameters of the process.
In the operating marine diesel engines the indication diagnostics tests are usually performed through a 0.5-1.0 me ter long indication channel which delays and disfigures the pressure signal being measured. the delay depends on the engine 's speed and load. the pressure sensor itself together with an amplifler is an additional source of delay and disfigurements, so the registered pressure curve is displaced even if theTDC piston's position hadbeen estimated with the highest accuracy. when the over exploited engine is being tested the angle of delay can achieve several degrees and differ for each cylinder. in that case cylinders' load is unequal and torsional vibrations occur in the engine operation. in case when some simplifying assumptions have been adopted the part of diagnostic information is lost what could lead to a false diagnosis. in the paper the attention is focused on the mistakes which could be made in the marine diesel engine diagnostics when different TDC assessment methods are used. TDC corrections with compression pressure analysis are possible only in case when crankshaft angle position is precise. in case of measurement with constant frequency such corrections are possible only when the engine is good balanced.
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Work of internal combustion engines, which are used as the driving source of cars, occurs not only at the full load, but also mostly at the part load, when the energy efficiency r/e is significant lower than in the optimal (nominal field) range of the performance parameters. One of the numerous reasons of this state is regular growing of the relative load exchange work of the IC engine. Using the worked out formulas it has been calculated that the relative load exchange work can achieve value up to 40 % at the part load (e.g. idle run) of the IC engine, whereby the engine speed influences the results too. As consequence of the growing of the relative load exchange work is the significant drop of the engine efficiency; from ca. 55 % down to ca. 25 %. The solutions of this problem are based on the fully electronic control of the motion of inlet and outlet valves, whereby the optimal internal recirculation ratio of flue gases should be taken into account. New reference cycles can be applied too.
PL
Analizę procesów termodynamicznych zachodzących w komorze spalania silnika spalinowego można prowadzić na podstawie znajomości jego obiegu porównawczego. Pomiar szybkozmiennego ciśnienia w cylindrze silnika spalinowego (indykacja) umożliwia określenie ekwiwalentnej liczby rozdziału ciepła V. Prawidłowy dobór rozdziału ciepła (do zaproponowanego obiegu porównawczego) pozwala wyznaczyć wartości takich wielkości jak: iloraz ciśnień f, iloraz objętości
The analysis of geological, laboratory and geophysical research results of Upper Jurassic carbonate rocks allowed to estimate fissurity indicator and investigation of fissured-cavernous zones in these complex' area. Researches of carbonate rocks mezostructure should be performed in the complex way, because these results help to draw practical conclusions about evaluation on account of reservoir properties. It should be accepted that only authoritative method of identification fissured zones doesn't exist.
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