Wyniki wyszukiwania - BazTech

1

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

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

Combustion Engines

|

2015

|

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.

2

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

|

2014

|

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.

3

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

|

2013

|

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.

4

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

|

2013

|

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.

5

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

|

2013

|

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.

6

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

|

2012

|

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.

7

Nanostructured bone-like scaffolds for restoration of trabecular bone remodeling capability

Nowak M., Firkowska I., Giersig M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2011

|

Vol. 59, nr 1

57-61

EN

This paper presents the theoretical study about carbon nanotube substrates for tissue engineering and its applications. Because the replacement of bone tissue with artificial tissue can violate the remodeling process completely, the artificial material should not only consist of the same material properties, but also exhibit other characteristics which are equally important and need to be taken into consideration. These are above all the mechanosensation. Besides replacing natural tissue, the nanostructured scaffolds presented in the paper can help the tissue growth by stimulating this process. The developed trabecular bone remodeling simulation method responsible for the nanostructured scaffold behavior is implemented here. Thus, the nanostructured bone-like scaffolds reflect the remodeling capability of the biological system, not only due to their application as replacement of natural tissue, but also due to their effects in the field of mechanosensation.

8

Nanorurki węglowe jako warstwa pośrednia na powierzchni katalitycznego reaktora utleniającego w układzie oczyszczania spalin

Ciałkowski M., Giersig M., Iskra A., Kałużny J., Babiak M.

Logistyka

|

2009

|

nr 6

CD-CD

PL

Nanomateriały i nanorurki stanowią stosunkowo nowy obszar nauki i praktyki przemysłowej. Niniejszy artykuł obejmuje przegląd zastosowań nanomateriałów w przemyśle samochodowym. Obszary zastosowań nanomateriałów podzielono na dwie grupy w zależności od stopnia zaawansowania procesu wdrożeniowego nanomateriałów. Szczególną uwagę poświęcono przy tym obszarom innowacyjnych zastosowań nanomateriałów, zastosowaniom w których możliwe byłoby wykorzystanie unikalnych własności nanomateriałów. Autorzy artykułu zaproponowali utworzenie warstwy pośredniej reaktora katalitycznego z nanorurek, oczekując istotnego zwiększenia powierzchni kontaktu warstwy katalitycznej ze spalinami. W artykule przedstawiono wstępne wyniki badań stopnia konwersji reaktora zbudowanego według zaproponowanej koncepcji oraz przedyskutowano kierunki dalszego rozwoju konstrukcji.

EN

The nanotubes and nanotechnologies are relatively new areas of science and engineering practice. This article should be concerned as a review of the selected nanotechnology applications in the automotive industry. The applications were divided into groups in respect of implementation advance level. Special attention was devoted to innovative nanomaterials application in areas where taking advantage of their unique features is possible. Authors presented the catalytic converter for combustion engine exhaust system application in which the nanotubes were used in order to increase the contact area of exhaust gases with catalytic layer. In the paper preliminary results of proposed catalytic reactor conversion ratio were presented and future directions of development were discussed.

9

Selected Possible Applications Of Nanometerials In Automotive Industry

Babiak M., Ciałkowski M., Giersig M., Iskra A., Kałużny J.

Journal of Polish CIMAC

|

2009

|

Vol. 4, no 2

15-20

EN

The nanotubes and nanotechnologies are relatively new areas of science and engineering practice. This article should be concerned as a review of the selected nanotechnology applications in the automotive industry. The applications were divided into groups in respect of implementation advance level. Special attention was devoted to innovative nanomaterials application in areas where taking advantage of their unique features is possible. Authors presented the catalytic converter for combustion engine exhaust system application in which the nanotubes were used in order to increase the contact area of exhaust gases with catalytic layer. In the paper preliminary results of proposed catalytic reactor conversion ratio were presented and future directions of development were discussed.