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1

Friction reducing performance of carbon nanotubes covered pistons in internal combustion engines – engine test results

Kałużny J., Merkisz J., Kempa K., Gapiński B., Wróblewski E., Stepanenko A., Al-Karawi M.

Combustion Engines

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2018

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R. 57, nr 1

14--24

EN

This article discusses the posibility of reducing friction losses in internal combustion engines by using carbon nanotubes, pointing out the large potential of this application. Experimental pistons were made of standard aluminum alloy and coated with a layer of nanotube deposits by spraying them with an aqueous solution containing the binder. The proposed technology of applying layers of nanotubes can be adopted in industrial-scale production. Engine tests were carried out showing a significant reduction of the engine motoring torque, up to 16% for the experimental pistons, thus confirming the favorable tribological properties of nanotubes observed in tribological research and reported by many authors. Supplementary tests were carried out: SEM, EDS, coordinate measuring technique, and x-ray tomography. An alternative technology for hierarchical nanotube multilayer coatings electro-deposition was proposed.

2

Piston assembly in the most powerful 2.0l diesel engine – case study of the current tribological system and innovative concepts for the future

Kałużny J., Merkisz J., Stepanenko A., Wróblewski E., Gapiński B., Piasecki A., Gallas D.

Combustion Engines

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2017

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R. 56, nr 4

127--133

EN

This article is a contribution to the ongoing debate on the scenario of the vehicle powertrains development. The directions of the internal combustion engines development in search of the possibility of effective economic and ecological indicators improvement have been indicated. It has been pointed out that this goal can be achieved through the use of nanotechnology in order to exceed the downsizing barriers resulting from the permissible mechanical loads for conventional materials. The article presents the study of the construction and materials used in the piston assembly of the most advanced four-cylinder, compression-ignition diesel engine currently in manufacture. Original concepts of nanotechnology have been proposed to reduce friction losses in major friction components of future engines with extremely high loads. The main idea is to verify the hypothesis that the sub-micron surface texture of the friction components obtained in the process of applying anti-wear outer layers can lead to an effective reduction of friction losses under real engine operating conditions. Computer simulations of the effects of introducing the surface texture in the upper sealing ring on friction loss confirm this hypothesis by showing friction value being reduced by 3-4% relative to the standard ring profile. In the summary, further advanced technologies designed to effectively utilize the unique properties of carbon nanotubes have been described.

3

An innovative system for piston engine combustion with laser-induced ignition of the hydrocarbon fuel consisting carbon nanotubes

Kałużny J., Merkisz J., Gallas D., Runka T., Kozak M., Pielecha I.

Combustion Engines

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2017

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R. 56, nr 1

3--14

EN

The article proposes the concept of a new piston engine combustion system that is designed to meet future-oriented ecological requirements. The concept is to use ethanol as a fuel, in which a slurry of carbon nanotubes would be formed, which are characterized by the ability to ignite using a pulse of laser light fed into the combustion chamber. Modifying the shape of the light beam that penetrates the combustion chamber would allow to control the position and the size of the area in which the ignition of fuel would occur. The originality of the concept is to combine the latest achievements in the field of nanotechnology in the construction of lasers and the production of biofuels, so as to contribute to improving the environmental performance of engines using the existing synergies. The article discusses the prospects for the use of bioethanol as a fuel with zero carbon balance, a critical review of related research on light pulse initiated ignition of hydrocarbon fuels from carbon nanotubes was presented, and a review of studies of laser ignition for conventional fuels. The results of studies of carbon nanotubes suspensions in a variety of fuels conducted by the authors in order to seek solutions for the stable dispersions formation, that are resistant to nanotube agglomeration and sedimentation. The summary indicates directions for further research highlighting the importance of environmental impact.

4

The investigation of experimental combustion engine elements conducted with use of atomic physics methods

Kałużny J., Iskra A., Babiak M.

Journal of KONES

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2015

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Vol. 22, No. 4

147--154

EN

The authors put forward in earlier publications the concept of using carbon nanotubes (CNT) in order to improve the functional characteristics of selected structural components of internal combustion engines. The main goal of applying carbon nanotubes is to take advantage of its unique properties, which cannot be found among traditional construction materials, to reduce emissions and fuel consumption. To achieve this goal it is essential to come to know about elements and materials behaviour in specific application, for example piston or catalytic converter. In this article, selected methods in the field of atomic physics applied to the study of experimental engine components produced using nanotechnology are presented. For example, the electron microscopy in conjunction with registration of the characteristic X-ray and Raman spectroscopy were used. These test methods are improving the knowledge of the properties and design of pistons and catalytic converters with surface coated with multi-walled carbon nanotubes. The results of elements surface analysis, which were diverted from the engines after a series of test stand investigations, offer insight into the processes that take place in layers of carbon nanotubes in actual engine operating conditions. The knowledge gained with application of atomic physics methods allows achieving further improvement of carbon nanotubes layers and its functional characteristics.

5

The application of carbon nanotubes for reducing the friction losses of internal combustion engine

Kałużny J., Iskra A., Giersig M., Kempa K.

Combustion Engines

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2015

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R. 54, nr 3

64--77

EN

Carbon nanotubes are a relatively new allotropic variety of carbon and due to a number of very favorable properties – including chemical and mechanical – are now under intensive investigation. Introduction to the main part of the article requires an overview of carbon nanotubes studies conducted by different authors, the results of which can provide important guidelines for possible use of the material in the construction of piston engines. The core of the article is the description of attempts to use carbon nanotubes made by the authors in order to improve the functional properties of various components of internal combustion engines, in particular to reduce losses caused by friction. Therefore, the results from the original study have been presented which indicate that the use of carbon nanotubes as an additive for engine lubricant can contribute to a significant reduction in friction losses. Article concludes with a discussion of the tasks that need to be completed in order to allow for an industrial application of carbon nanotubes.

PL

Nanorurki węglowe stanowią niedawno poznaną odmianę alotropową węgla i ze względu na wiele wyjątkowo korzystnych właściwości – między innymi chemicznych i mechanicznych – poddawane są obecnie intensywnym badaniom. Wprowadzeniem do zasadniczej części artykułu jest przegląd takich badań nanorurek węglowych prowadzonych przez różnych autorów, których wyniki mogą stanowić istotne wskazówki do zastosowania tego materiału w konstrukcji tłokowych silników spalinowych. Główną część pracy stanowi opis podjętych przez autorów tego artykułu prób wykorzystania nanorurek węglowych do poprawy właściwości funkcjonalnych różnych elementów tłokowych silników spalinowych, w szczególności w celu ograniczenia strat tarcia. W tym zakresie przedstawiono wyniki oryginalnych badań wskazujące, że zastosowanie nanorurek węglowych jako dodatku do oleju smarującego może przyczynić się do istotnego zmniejszenia strat tarcia. Artykuł podsumowują rozważania dotyczące zadań, które muszą być wykonane aby umożliwić przemysłowe zastosowanie nanorurek węglowych.

6

The impact of oil elasticity on the piston-cylinder group

Iskra A., Babiak M., Kałużny J.

Journal of Polish CIMAC

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2014

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Vol. 9, no 2

83--89

EN

There are numerous programs that allow to evaluate the parameters of the oil film between the elements of the piston-cylinder group. By incorporating a large number of geometrical parameters of the elements of the piston-cylinder group, one obtains a substantial convergence of computer simulation with the results achieved on the test bench. At present, the authors are conducting studies on the possibility of improving the cooperation parameters of the elements of the piston-cylinder group by synthesizing a layer of carbon nanotubes (CNT) on the lateral surface of the piston. Preliminary studies showed a significant decrease in the friction force of the piston on the cylinder bearing surface when the lateral surface of the piston is coated with a layer of CNT. The attempts to use the Reynolds equation in order to determine friction loss by means of a computer model showed significant differences between the results of computer simulation and the experimental results. The authors came to a conclusion that the differences may be due to two causes: - oil film does not consist of laminar layers - besides viscosity, lubricating oil shows elasticity which affects the value of friction force Because the estimated Reynolds number virtually excludes turbulent flow, one should assume that the structure of the lubricating oil in contact with the layer of CNT gives specific elasticity to such a composite. As a consequence, in order to determine the parameters of the oil film, one should adopt the Maxwell model rather than the Newton one, which is the basis of the Reynolds equation. It was found that the Maxwell model of oil film enables obtaining a more accurate computer model according to which internal friction in oil film is generated. The utilitarian effect is indeed the reduction of friction forces, which indicates the desirability of coating the lateral surface of the piston with a layer of CNT.

7

Selected applications of carbon nanotubes in construction of internal combustion engine

Kałużny J., Iskra A., Babiak M., Krzymień P., Giersig M., Kempa K.

Journal of Polish CIMAC

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2014

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Vol. 9, no 2

105--116

EN

For over hundred years the internal combustion engine has been applied as the drive of various vehicles and it is continuously improved. The most important requirements that should be satisfied by future engines concern reduction in fuel consumption and exhaust emissions preserving possibly low cost of engine manufacturing. In order to fulfill such demands a concept of so called "downsizing" has been proposed which concept is based on high values of mean effective pressure, and as a consequence high mechanical and thermal loads. Further increase of engine power per liter is still possible but new materials are needed in order to keep the manufacturing costs at the reasonable level. The paper presents an analysis of operational conditions of selected parts of supercharged engines constructed according to the downsizing concept and shows areas where the use of new materials could be most profitable. Results of engine tests carried out using modernized catalytic reactors and pistons in which advantages of the carbon nanotubes unique properties were deliberately taken have been presented in this paper as well. The obtained results allow to conclude that the nanotube layer over the piston skirt offers the friction losses reduction by as much as 16% relative to the whole engine. The observed properties of nanotubes can be profitable in a number of applications indicated in the paper.

8

Measurements of a piston bearing surface shape with carbon nanotubes coating

Babiak M., Iskra A., Kałużny J., Gapiński B.

Journal of Polish CIMAC

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2014

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Vol. 9, no 2

7--16

EN

The piston bearing surface shape is directly combined with such phenomena like thermal expansion, lateral movements of a piston and with friction processes between piston and cylinder liner. During the examination of the most favourable piston shape all of these phenomena have to be considered, so the flnal result will provide Iow friction losses and engine efficiency improvement, with keeping in mind the reąuirements which result from piston lateral movements. In order to achleve the best possible result ofa optimization process the piston bearing surface as a rule arę coated with graphitoidal varnish. The authors have advanced this idea and used the lacąuer with carbon nanotubes(CNT) additive. In the paper issues connected with measurements of a piston bearing surface, which is coated by CNT, arę presented. The methodology of carried out measurements with use of coordinate measuring machinę is discussed. There arę also presented the results of piston bearing surface shape measurements before mounting into the engine and after engine tests. Obtained results allow to estimate the wear degree ofa CNT coating.

9

The influence of applying a layer of carbon nanotubes on the piston bearing surface on friction losses

Iskra A., Babiak M., Kałużny J.

Combustion Engines

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2014

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R. 53, nr 4

26--31

EN

The paper presents results of testing the resistance to motion of pistons whose bearing surface was coated with a layer of carbon nanotubes (CNTs). A part of this paper was devoted to the problems of applying a layer of nanotubes on the surface of an aluminum alloy, which is the most common material used for pistons. Obtaining a layer of nanotubes of a very narrow margin of tolerance was a difficult technological problem to overcome. A standard process of growing a layer of nanotubes leads to corrosion damage of the side surface of pistons; therefore, new technologies were developed which allow for obtaining a permanent layer of nanotubes less than 5 microns thick. Pistons with the bearing surface coated with a layer of nanotubes were mounted to the engine, and then measurements of the moment of momentary resistance to motion were performed. Also capturing phases of the engine work cycles in which the layer of nanotubes gives the best results seems to be possible. At present, long-term research is being carried out in order to determine the degree of the risk of exfoliation of the layer of CNT under the conditions of high mechanical and thermal loads.

PL

W artykule przedstawiono wstępne wyniki badań oporów ruchu tłoków pokrytych warstwą nanorurek węglowych. Część opracowania poświęcono również problemom nakładania warstwy nanorurek na powierzchni stopu aluminium. Uzyskanie warstwy nanorurek o bardzo wąskim polu tolerancji stanowiło trudny do rozwiązania problem technologiczny. Standardowy proces syntezy warstwy nanorurek prowadzi do korozyjnego uszkodzenia powierzchni bocznej tłoków, dlatego zostały opracowane nowe technologie pozwalające uzyskać trwałą warstwę nanorurek o grubości od kilkunastu do kilkudziesięciu mikrometrów. Tłoki o powierzchniach bocznych pokrytych warstwą nanorurek zamontowano do silnika o napędzie zewnętrznym, a następnie wykonano pomiary momentu chwilowych oporów ruchu, co umożliwia wskazanie tych faz cyklów pracy silnika, w których warstwa nanorurek daje największe korzyści. Obecnie prowadzone są długotrwałe badania mające na celu wyeliminowanie niebezpieczeństwa złuszczania się warstwy nanorurek w warunkach dużego obciążenia mechanicznego i termicznego.

10

Porównanie oporu ruchu tłoków pokrytych warstwą nanorurek węglowych z tłokami standardowymi

Iskra A., Babiak M., Kałużny J.

Prace Naukowe Politechniki Warszawskiej. Transport

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2013

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z. 98

215--223

PL

W artykule przedstawiono wstępne wyniki badań oporów ruchu tłoków pokrytych warstwą nanorurek węglowych. Część opracowania poświęcono również problemom nakładania warstwy nanorurek na powierzchni stopu aluminium. Uzyskanie warstwy nanorurek o bardzo wąskim polu tolerancji stanowiło trudny do pokonania problem technologiczny. Standardowy proces hodowania warstwy nanorurek prowadzi‚ do korozyjnego uszkodzenia powierzchni bocznej tłoków, stąd też zostały opracowane nowe technologie pozwalające uzyskać trwałą warstwę nanorurek o grubości poniżej 5 mikrometrów. Tłoki o powierzchniach bocznych pokrytych warstwą nanorurek zamontowano do silnika o napędzie zewnętrznym, a następnie wykonano pomiary momentu chwilowych oporów ruchu, co pozwala uchwycić te fazy cyklów pracy silnika, w których warstwa nanorurek daje najlepsze rezultaty. Obecnie prowadzone są długotrwałe badania mające na celu określenie stopnia niebezpieczeństwa złuszczania się warstwy nanorurek w warunkach dużego obciążenia mechanicznego i termicznego.

EN

The paper presents preliminary results of the resistance to motion test of pistons coated with a layer of carbon nanotubes (CNTs). A significant part of this paper concerns the problems of coating the surface of an aluminium alloy with a layer of carbon nanotubes. Obtaining a layer of carbon nanotubes of a very narrow margin of tolerance was a difficult technological problem to overcome. A standard process of growing a layer of CNTs leads to a corrosion damage of the side surface of pistons. Therefore, the new technologies were developed allowing obtaining a durable layer of carbon nanotubes less than 5 microns thick. Pistons which side surfaces were coated with a layer of nanotubes were mounted to an engine with an external drive, and then measurements of the moment of momentary resistance to motion were performed, which enables capturing these phases of the engine work cycles in which the layer of nanotubes gives the best results. At present, long-term researches are being carried out in order to determine the risk of exfoliation of the layer of nanotubes under the conditions of heavy mechanical and thermal loads. The special nanotechnology method cold nanosphere lithography has been invested to control the structural properties sand growth of multiwall carbon nanotubes. The preliminary analysis of dismantled pistons revealed that nanotubes layers were partially worn off at the peaks of micro roughness but in the valleys the nanotubes accurately adhered to the piston lateral surface.

11

Stabilizing piston speed with a layer of carbon nanotubes on the lateral surface of the piston

Iskra A., Babiak M., Kałużny J., Giersig M., Kempa K.

Journal of Polish CIMAC

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2013

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Vol. 8, no 1

7--14

EN

The paper presents the possibility of stabilizing higher harmonics of piston speed generated by torsional vibrations of the shaft. As a result of torsional vibrations, the transient speed of the piston deviates from the values resulting from the known formulae describing geometrical dependences of the piston position versus the angle of rotation of the crankshaft [1]. This phenomenon causes the desired effect of damping torsional vibrations. As it is known, in larger engines of the cylinder diameter exceeding 120mm and the number of in-line cylinders greater than or equal to 6, structural damping is insufficient and it becomes necessary to use torsional vibration dampers. In article [2] attention was drawn to the effect of damping higher harmonics of the moment generated by the engine whose lateral surfaces are coated with layers of nanotubes, which was not however, the main subject of the article. This work presents a preliminary analysis and determinants of the efficiency of vibration damping due to the impact of nanotubes on the reduction of the amplitude of higher harmonics of the moment generated by the engine. In addition, the possible mechanism of the phenomenon of vibration damping by a layer of nanotubes is presented. However, one should emphasize that at this stage the authors do not close the debate concerning the mechanical properties of the structures based on carbon nanotubes (CNTs), but in fact, they open up such a discussion. Besides the confirmed properties of nanotubes, such as extremely high tensile strength of properly structured fiber formed by CNTs, there is very little data concerning the properties of chaotic structures in which nanotubes combine in larger structures adopting any directions. No less important is the base on which nanotubes are grown, and it can be very different. The authors of the paper have presented preliminary results of a positive impact of selected properties of CNTs on the vibrations of the crankshaft.

12

The properties of damping vibrations by a layer of carbon nanotubes on the lateral surface of a piston

Iskra A., Babiak M., Kałużny J., Giersig M., Kempa K.

Journal of KONES

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2013

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Vol. 20, No. 3

177--184

EN

As a result of applying the hydrodynamic lubrication theory in the piston-cylinder group of a combustion engine, the authors have obtained the opportunity for practical elimination of abrasion of this unit. However, it turns out that in the case of the engine start, especially after a longer standstill and before the oil film is formed, the piston lateral surface’s micro-roughness comes into direct contact with the cylinder bearing surface. For this reason, manufacturers more and more commonly apply a special layer on the lateral surface of a piston, which decreases the friction force and eliminates very damaging effects of the so-called semi-dry friction. It turns out that applying an enriching layer on the lateral surface of the piston may result in an additional effect, which is not usually associated with the pistoncylinder unit. This effect is the damping of torsional vibrations. Thus, despite the seemingly insignificant properties of materials which the elements of the kinematic pair are made of, as a result of the occurrence of the layer with specific properties on these elements, one may find that these layers – even when they are separated by the oil film – can change the parameters of collaboration of the elements of the kinematic pair. In particular, it concerns generating and damping vibrations, and in such circumstances frictional losses may also be subject to change, which is the main domain of the conducted research presented in this paper. The article analyzes various effects which are caused by applying a special layer formed of carbon nanotubes (NCT in short) on the lateral surface of the piston.

13

Wpływ strategii podziału dawki oleju napędowego na termodynamiczne i optyczne wskaźniki spalania w maszynie pojedynczego cyklu

Kaźmierowski J., Pielecha I., Czajka J., Wisłocki K., Borowski P., Kałużny J.

Combustion Engines

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2013

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R. 52, nr 3

677--685

PL

W artykule omówiono wyniki badań wpływu strategii podziału dawki paliwa na wskaźniki spalania oleju napędowego wraz z analizą spalin z Maszyny Pojedynczego Cyklu. Analizie poddano także materiał zdjęciowy dotyczący okresu od początku wtrysku dawki paliwa do początku wystąpienia ognisk spalania. Dokonano wariantowania liczby dawek ich wielkości oraz czasów przerw między nimi, a także współczynnika nadmiaru powietrza. Dokonano oceny porównawczej wskaźników termodynamicznych procesu spalania uzyskanych z wykresu indykatorowego (Pcyl-max, (dPcyl/dt)max, czas opóźnienia zimnych i gorących płomieni) w zestawieniu z materiałem filmowym.

EN

The results of research on the influence of the fuel dose division strategy on the operational and optical indexes of the engine and combustion process have been discussed in the paper. The paper also contains an exhaust gas analysis conducted with the use of a Rapid Compression Machine (RCM). The recorded images related to the period from the onset of injection to the beginning of combustion spots have also been analyzed. The following have been varied: number of doses, the size of doses, dwell times and the excess air coefficient. The author performed a comparative analysis (against the recorded images) of the thermodynamic indexes of the combustion process obtained from the indicator traces (Pcyl-max, (dPcyl/dt)max, delay time of the hot and cold flames).

14

The resistance to motion of internal combustion engine during the running-in process

Iskra A., Babiak M., Kałużny J.

Combustion Engines

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2013

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R. 52, nr 3

599--603

EN

It is common that service manuals of modern passenger car do not establish any special rules of engine running-in process. It does not mean that the running-in process does not take place in the combustion engine, but the geometrical precision of engine elements is so high that manufacturers permit to operate the engine with full power from the very beginning of passenger car operation. To determine if such approach is correct the investigation of resistance to motion during engine initial operation period was made. The friction losses sum of all kinematic couples is the basic parameter that allows to evaluate the advance of engine running-in process. Many factors have influence on resistance to motion of combustion engine which means that determination of friction forces changes during running-in process is very difficult. The investigations presented in the paper were made on the engine in which most of the friction losses components are eliminated and only crank mechanism is considered. Obtained results allow to state that manufacturers resigned to early from running-in prescription which would guarantee the maximization of service life after running in period. Presented results of resistance to motion torque investigations are also the preliminary attempt to determine in which engine cycle phase the differences during and after running-in period are greatest.

PL

Obecnie instrukcje użytkowania samochodów osobowych nie przewidują szczególnych zasad docierania silnika w okresie początkowej eksploatacji. Nie oznacza to oczywiście, że proces docierania został wyeliminowany, jednak precyzja wykonania oraz jakość powierzchni współpracujących elementów pozwalają na pełne obciążenie silnika nowego samochodu. W celu określenia zasadności ww. poglądu zostały przeprowadzone badania zmian przebiegu sił tarcia w początkowym okresie eksploatacji silnika. Straty tarcia w parach kinematycznych silnika spalinowego są podstawowym parametrem pozwalającym ocenić zaawansowanie procesu docierania silnika. Niestety na opory ruchu silnika składa się szereg czynników, co powoduje, że określenie zmian sił tarcia w okresie docierania jest bardzo trudne. Zaprezentowane w artykule badania przeprowadzono na silniku spalinowym, w którym wyeliminowano większość składowych momentu oporu ruchu. Uzyskane wyniki pozwalają wyrazić opinię, że w obecnych instrukcjach obsługi silników spalinowych zbyt wcześnie zrezygnowano z zaleceń gwarantujących maksymalne wydłużenie eksploatacji po okresie docierania po okresie docierania. Zaprezentowane wyniki badań momentu oporu ruchu są również wstępną próbą określenia, w jakim momencie cyklu pracy silnika różnice w okresie docierania i po tym okresie są największe.

15

The influence of cylinder disengaging on the friction resistance in the piston-cylinder assembly

Iskra A., Babiak M., Kałużny J.

Combustion Engines

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2013

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R. 52, nr 3

593--598

EN

On the combustion engine specific fuel consumption characteristic the high efficiency area is limited to the high engine loads. But most of the time the necessary engine power used for driving is between 20 to 50 % of the nominal engine power, which means that the engine works beyond the high efficiency range. This situation can be changed with disengaging part of the cylinders by cutting off the air and fuel supply to these cylinders, which means that the other cylinders will work with higher load to compensate power loss of disengaged cylinders. Such idea is known for long time but its practical realization meats series of problems. The long lasting idle running of piston-rings-cylinder group may have impact on engine durability and friction losses generated by switched off cylinders. In the paper friction losses of the piston-cylinder assembly of four cylinder in-line engine are presented. Three cases are considered: maximum efficiency working range, idle run and 50 % of the engine rated power within maximum efficiency range. The simulations were made for the classic three piston rings packet and piston with carbon nanotubes layer on its skirt. On the basis of carried out simulations conclusions about purposefulness of cylinder disengaging were formulated.

PL

Z charakterystyki ogólnej silnika spalinowego wynika, że pole pracy charakteryzujące się dużą sprawnością cieplną jest bardzo ograniczone. Najczęściej jednak moc wykorzystywana na jazdę stanowi 20 do 50% mocy nominalnej silnika a to oznacza, że silnik pracuje poza obszarem najwyższych sprawności. Sytuację można zmienić wyłączając z zasilania w paliwo część cylindrów silnika wielocylindrowego. O ile koncepcja taka znana jest od dziesięcioleci to jej praktyczna realizacja napotyka na szereg trudności. Długotrwała praca zespołu tłok–pierścienie–cylinder na biegu jałowym może wpłynąć na trwałość silnika a straty tarcia generowane w wyłączonych cylindrach obniżają sprawność ogólną tak użytkowanego silnika. W artykule przedstawiono straty tarcia w grupie tłokowo – cylindrowej silnika czterocylindrowego dla trzech przypadków: silnika pracującego w polu maksymalnej sprawności ogólnej, silnika na biegu jałowym oraz silnika generującego połowę mocy odpowiadającej pracy w polu maksymalnej sprawności. Symulacje przeprowadzono z uwzględnieniem pakietu trzech pierścieni na tłoku oraz powierzchni bocznej tłoka uszlachetnionej warstwą propoślizgową wykonaną z nanorurek węglowych. Na podstawie przeprowadzonych symulacji sformułowano wnioski określające celowość stosowania systemu wyłączania zasilania paliwem części cylindrów, przez co pracujące cylindry generują moc w obszarze maksymalnej sprawności ogólnej.

16

Investigations of the fuel injection and atomization with the use of laser illumination

Kałużny J., Czajka J., Pielecha I., Wisłocki K.

Combustion Engines

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2013

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R. 52, nr 3

469--475

EN

The paper presents some aspects of the application of selected methods of optical research whose aim is to obtain information on the course of the atomization and evaporation processes in the combustion chamber. The paper shows images of a gasoline fuel spray when injected to a high-pressure chamber. These images have been recorded using conventional sources of light and laser illumination. Research with the use of a YAG pulsed laser of high illumination pulse energy enabled an assessment of the fuel distribution in the transverse cross-section of the fuel spray. The paper describes such a possibility of modification of the experiment using laser illumination as to obtain information on the spatial distribution of both the liquid and gaseous phase of the injected fuel.

PL

W artykule omówiono niektóre aspekty stosowania wybranych metod badań optycznych, których celem jest uzyskanie informacji o przebiegu procesu rozpylenia i odparowania paliwa w komorze spalania silnika spalinowego. Przedstawione zostały obrazy strugi benzyny wtryskiwanej do komory ciśnieniowej zarejestrowane przy wykorzystaniu konwencjonalnych źródeł światła i oświetlenia laserem. Badania z wykorzystaniem lasera impulsowego typu YAG o dużej energii impulsu oświetlającego umożliwiły ocenę rozkładu paliwa w poprzecznym przekroju strugi paliwa. Opisano możliwość takiej modyfikacji eksperymentu prowadzonego z oświetleniem laserowym, aby uzyskać informację zarówno o przestrzennym rozkładzie fazy ciekłej, jak i fazy gazowej wtryskiwanego paliwa.

17

Coating the bearing surface of a piston with a layer of nanotubes as a means of reducing friction

Babiak M., Carnahan D., Giersig M., Iskra A., Kałużny J., Kempa K.

Combustion Engines

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2013

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R. 52, nr 3

525--529

EN

Striving to improve the overall efficiency of combustion engines under real operating conditions of vehicles is effectively implemented by downsizing and turbo-charging. Engine turbo-charging leads to an increase in mechanical loads, in the piston-cylinder group in particular. In order to take full advantage of the opportunity to improve the efficiency of the engines built according to the concept of downsizing, it is appropriate to optimize the piston-cylinder cooperation, especially in terms of friction losses. This paper examines the possibility of replacing conventional layers covering the bearing surface of the piston with layers formed by nanomaterials. The obtained images of layers of carbon nanotubes (CNTs) on the surface of experimental pistons are presented by means of a scanning electron microscope (SEM). The pistons were embedded in an engine and tested for friction losses.

PL

Dążenie do poprawy sprawności ogólnej silników spalinowych w rzeczywistych warunkach eksploatacji pojazdów jest skutecznie realizowane przez downsizing i doładowanie silników. Doładowanie silników prowadzi do wzrostu obciążeń mechanicznych, szczególnie w grupie tłokowo-cylindrowej. Dla pełnego wykorzystania możliwości poprawy sprawności silników zbudowanych według koncepcji downsizingu celowa jest optymalizacja współpracy tłoka z cylindrem, szczególnie w aspekcie strat tarcia. W artykule przeanalizowano możliwość zastąpienia konwencjonalnych warstw pokrywających powierzchnię nośną tłoka przez warstwy utworzone z nanomateriałów. Przedstawiono uzyskane za pomocą elektronowego mikroskopu skaningowego zdjęcia warstw nanorurek węglowych na powierzchni eksperymentalnych tłoków. Tłoki te zostały zamontowane w silniku i poddane badaniom strat tarcia, wyniki badań przedstawiono i omówiono w artykule.

18

Innowacyjna konstrukcja utleniającego reaktora katalitycznego uwzględniająca udział węglowodorów w spalinach

Iskra A., Kałużny J., Babiak M., Marszałkowski K.

Zeszyty Naukowe Akademii Marynarki Wojennej

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2012

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R. 53 nr 2 (189)

55-61

PL

Obserwowany wzrost świadomości ekologicznej leży u podstaw inicjatyw mających na celu prawne zagwarantowanie ograniczenia uciążliwości dla środowiska wszelkich pojazdów z silnikami spalinowymi. Zaostrzenie norm emisji spalin wymusza poszukiwanie nowych rozwiązań technicznych, szczególnie w zakresie układów oczyszczania spalin. W artykule przedstawiono koncepcję utleniającego reaktora katalitycznego z użyciem nanomateriałów. Naniesienie nanorurek węglowych na standardowy nośnik ceramiczny umożliwia zwiększenie powierzchni kontaktu warstwy katalitycznej ze spalinami przy ograniczeniu ilości kosztownego metalu szlachetnego zastosowanego do produkcji reaktora. Przedstawione w artykule wyniki badań emisji spalin przeprowadzonych na nowoczesnym silniku pojazdu użytkowego o zapłonie samoczynnym, z zastosowaniem opisanego innowacyjnego reaktora katalitycznego, potwierdzają możliwość uzyskania wymienionych wyżej, teoretycznie przewidzianych korzyści.

EN

The rise in ecological awareness underlines the initiatives which aim at providing legal guarantee for limitation of negative effect of all internal combustion engine vehicles on the natural environment. More restrictive emissions standards require a search for new technological solutions and designs especially in the field of exhaust gas purifying systems. The paper presents a concept of new oxidizing catalytic converter based on nanomaterials. The carbon nanotubes coating of the standard ceramic carrier allows increasing the contact area of exhaust gas with catalytic layer while reduction of the noble metals used to build a reactor. The results of experimental investigations, presented in the paper, which were carried out on modern vehicle CI engine with the innovative catalytic converter confirm the possibility of obtaining the theoretical benefits mentioned above.

19

Comparing the resistance to motion of pistons coated with a layer of nanotubes with standard pistons

Iskra A., Babiak M., Kałużny J., Giersig M., Kempa K.

Journal of KONES

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2012

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Vol. 19, No. 2

227-233

EN

The paper presents preliminary results of testing the resistance to motion of pistons coated with a layer of carbon nanotubes (CNTs). A significant part of this paper was devoted to the problems of putting a layer of nanotubes on the surface of an aluminum alloy. Obtaining a layer of nanotubes of a very narrow margin of tolerance was a difficult technological problem to overcome. A standard process of growing a layer of nanotubes leads to a corrosion damage of the side surface of pistons; therefore, new technologies were developed allowing for obtaining a permanent layer of nanotubes less than 5 microns thick. Pistons whose side surfaces were coated with a layer of nanotubes were mounted to an engine with an external drive, and then measurements of the moment of momentary resistance to motion were performed, which enables capturing these phases of the engine work cycles in which the layer of nanotubes gives the best results. At present, long-term research is being carried out in order to determine the degree of the risk of exfoliation of the layer of nanotubes under the conditions of large mechanical and thermal loads. The special nanotechnology method cold nanosphere lithography has been invested to control the structural properties sand growth of multiwalled carbon nanotubes. The preliminary analysis of dismantled pistons revealed that nanotubes layers were partially worn off at the peaks of micro roughness but in the valleys, the nanotubes accurately adhered to the piston lateral surface.

20

Wpływ temperatury cieczy chłodzącej i oleju na straty tarcia w tłokowym silniku spalinowym

Iskra A., Kałużny J., Babiak M.

Czasopismo Techniczne. Mechanika

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2012

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R. 109, z. 3-M

183--190

PL

W artykule przedstawiono wyniki badań strat tarcia w silniku spalinowym, uzyskane na stanowisku modelowym, wyposażonym w specjalny układ regulacji temperatury, zapewniający znacznie większą stabilność temperatury niż ma to miejsce w standardowych układach. Podstawowym warunkiem obiektywności badań silników spalinowych jest utrzymanie powtarzalnych warunków prowadzenia eksperymentu. Omówiono wyniki badań laboratoryjnych zależności momentu wywołanego tarciem od temperatury oleju w misce olejowej oraz wyniki symulacji komputerowych zmian momentu tarcia wywołanych lokalnym przyrostem temperatury na gładzi cylindrowej. Sprecyzowane wnioski pozwalają ocenić wpływ temperatury oleju na straty tarcia w głównych węzłach tarcia silnika spalinowego.

EN

In the paper the results of researches, which were obtained at test stand equipped with special temperature control system which assures much more stabilization of temperature than in regular temperature control systems, are presented. The main requirement of every test objectiveness, especially of combustion engine tests, is to ensure the conditions repeatability. The results of laboratory researches over friction torque and lubricating oil temperature relation are discussed. Computer simulations results of friction torque changes caused by local oil temperature increment on the cylinder liner are also presented. Precise conclusions allow to evaluate the influence of the oil temperature at the friction losses in main friction pairs of the combustion engine.