Wyniki wyszukiwania - BazTech

1

Ocena zawodności sieci elektroenergetycznej średniego napięcia eksploatowanej w wybranym rejonie

Stobiecki A., Chojnacki A. Ł., Kaźmierczak A.

Wiadomości Elektrotechniczne

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2017

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R. 85, nr 2

16--19

PL

W artykule zamieszczono analizę zawodności linii przesyłowych średniego napięcia eksploatowanych na terenie przykładowego rejonu energetycznego.

EN

In this paper provided an analysis of failures of medium voltage transmission lines operated in the sample area of energy.

2

Ocena możliwości stosowania lamp LED jako zamienników świetlówek T8 w tradycyjnych oprawach oświetleniowych

Zalesińska M., Kaźmierczak A., Siewierski R., Górczewska M.

Poznan University of Technology Academic Journals. Electrical Engineering

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2017

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No. 92

177--187

PL

Od kilku lat dokonuje się gwałtowny rozwój półprzewodnikowych źródeł światła. Na rynku pojawia się coraz więcej zamienników LED dla dotychczas stosowanych źródeł światła, w tym także dla świetlówek liniowych. Nie zawsze jednak o lampach LED można powiedzieć, że są bezpośrednimi zamiennikami. W laboratorium Zakładu Techniki Świetlnej i Elektrotermii przeprowadzono badania fotometryczne i elektryczne wybranego zamiennika lampy fluorescencyjnej 36W współpracującego z dwoma typowymi oprawami oświetleniowymi stosowanymi w oświetlaniu pomieszczeń edukacyjnych. Przedstawiono wyniki badań i ich analizę. Przeprowadzono ocenę możliwości stosowania lamp LED w oprawach oświetleniowych, jako bezpośrednich zamienników świetlówek liniowych.

EN

For a few years there has been rapid development of semiconductor light sources. Commercially appears more and more replacements LED for used light sources, including for linear fluorescent lamps. However, does not always, LED lamps can be say that they are direct substitutes. In the laboratory, of Division of Lighting and Electro Heating Engineering, was conducted research photometric and electrical chosen alternative fluorescent lamp 36W cooperating with two typical luminaires used in lighting educational spaces. The article presents the results of research and analysis. An assessment of the possibility of using LEDs in the luminaires as direct replacements for linear fluorescent lamps.

3

Energy state impact on friction and wearing in combustion engines

Borkowska J., Kaźmierczak A.

Journal of KONES

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2017

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Vol. 24, No. 4

25--30

EN

Friction pairs are designed from elements, where is very difficult to define in unequivocal way all optimal parameters. Research on stability of friction pairs are focused on the surface and the top layer of surface in the parts. The main goal is find new solutions to design and material, thereby achieving one million kilometres of mileage to main repair in the case of internal combustion engines. The biggest structural difficulties are noticeable in friction pairs where we can observe sliding and returning motion, which is also connected with sealing function. Piston – ring – cylinder assembly of combustion engine has many friction pair's examples, also one of them, which decide about fastness to wear. A typical example of such a pair is first sealing ring – cylinder sleeve, called further in piston – rings – cylinder unit in combustion engine. Engineers are currently seeking an additional factor, which would be unable to gain the reduction of tangential force by reducing the friction coefficient in elements of friction pair during operations. Such a factor may be the surface free energy that results from molecular structure and nature of the bonds between the molecules present in the material. Components of surface free energy determine the tribological properties of the material, which is reflected in the stability of the units. The work aims to show the possibilities and benefits of the application of this new method in order to reduce wearing, which is consistent with the observed trend of technology development.

4

Research and analysis of the results from the tribotester test for piston

Borkowska J., Kaźmierczak A.

Combustion Engines

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2017

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R. 56, nr 2

14--17

EN

Piston – ring – cylinder assembly of combustion engine has a lot of friction pairs examples, also one of them which decide about fastness to wear, it means first sealing ring – cylinder, called further very simply ring – cylinder unit. During work of this unit we can observe wear of piston, precisely – of coating which is deposited on ring to prolong service life. Objective of this work was to realize a test of roll-block type on tribotester to set durability of piston sample. Within the framework of this test were investigated a prototyped piston’s rings with diamond embankment. Piston rings are made of diamond coating technology with a porous chromium coating, where in pores is deposited on said diamond powder with a grain size about 1 micron. The work will be carried out of an analysis of collaboration piston – rings – cylinder unit in internal combustion engine and an analysis of the use of hard materials in friction pairs, including powders. The work aims to show the possibilities and benefits of the application of new protective coatings to reduce their wearing, which is consistent with the observed trend of technology development.

5

Research and analysis of the results of the internal combustion engine locomotive during the 85-hour endurance test

Borkowska J., Kaźmierczak A.

Journal of KONES

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2016

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Vol. 23, No. 2

53--59

EN

Piston – ring – cylinder assembly of combustion engine has many friction pairs examples, also one of them which decide about fastness to wear, it means first sealing ring – cylinder, called further very simply ring – cylinder unit. During work of this unit, we can observe wear of piston, precisely – of coating which is deposited on ring to prolong service life. Objective of this work was to realize a test of set durability of railway engine EMD645 with power about 1300 kW. Within the framework of this test were investigated a prototyped piston’s rings with diamond embankment. Piston rings are made of diamond coating technology with a porous chromium coating, where in pores is deposited on said diamond powder with a grain size about 1 micron. The work will be carried out of an analysis of collaboration piston – rings – cylinder unit in internal combustion engine and an analysis of the use of hard materials in friction pairs, including powders. Will be performed research of material and description of diamond powder, which will be applied to the piston rings. After stability, testing in the locomotive engine EMD645 on the basis of the collected results will be developed conclusions of the wearing intensity on piston ring and relating them to the requirements for coatings. The work aims to show the possibilities and benefits of the application of new protective coatings on structural elements of the internal combustion engine in order to reduce their wearing, which is consistent with the observed trend of technology development.

6

Arkusz kalkulacyjny - czy to jeszcze ma sens?

Kaźmierczak A.

Utrzymanie Ruchu

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2015

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Nr 1

75--76

PL

Pracownicy działu utrzymania ruchu są chyba najbardziej niedoceniani w zakładach produkcyjnych. Chwali się ich dopiero w momencie wystąpienia awarii. Wiele firm marginalnie traktuje takie rutynowe działania jak prawidłowa konserwacja, regularne przeglądy czy podejmowanie czynności zalecanych przez producenta dla danej maszyny. Niekiedy zignorowanie drobnej usterki lub pobieżne jej usunięcie prowadzi do przestoju całej produkcji. Wielu pracowników działu UR stara się im zapobiec, uzupełniając specjalne arkusze kalkulacyjne oraz gromadząc dokumentację papierową. Wszystko wygląda jak kartoteka chorego u lekarza z małą pomocą pliku xls.

7

Various designs of the two-stroke engine heads with the valve flushed system

Łoza Ł., Kaźmierczak A., Borkowska J., Skorupa P., Krakowian K., Cienciała M.

Journal of KONES

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2015

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Vol. 22, No. 4

187--190

EN

The two-stroke engines have never acquired the popularity of the four-stroke engines due to their inherent performance limitations. The tasks of many engineering teams were to find the basic causes, which resulted in the inferior performance of these engines. Today’s task is to build a two-stroke engine whose performance could match that of a four-stroke engine in areas of common use. The most typical performance problems of a two-stroke engine are high petrol consumption caused by low efficiency, toxic by-products of combustion being emitted into the atmosphere (caused by oil present in the petrol), and uneven and loud engine noise. The greatest challenge is to achieve a good chamber purge during one stroke in which the fresh fuel mixture flows through the piston-controlled inlet port while at the same time the fumes are being exhausted through the outlet port. This in contrast with the four-stroke engines where the intake and exhaust are each done with two separate strokes. From the energy point of view, the two-stroke engine is not efficient because a certain amount of fresh fuel is being wasted in the exhaust fumes. We propose to replace the piston-controlled cam with the valve-flushed system, which will cause the combustion process to become more efficient. The purpose of this paper is to present various designs of the engine heads and analyse their performance. The goal of this proposal is to choose the best combination of these engine heads in order to achieve the optimum overall engine performance.

8

The numerical calculation module for piston rings

Kaźmierczak A., Tkaczyk M.

Journal of KONES

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2015

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Vol. 22, No. 3

301--307

EN

The piston with piston rings and bearing surface is a self-contained and highly complex tribological system. One of the most widespread global friction pairs traversed by reciprocating a pair of ring - cylinder liner piston - rings - cylinder internal combustion engine. Group PRS combustion engine is the solution generating considerable friction. Various researchers estimate the share of friction losses, per node piston rings - cylinder liner, at 19 to 60% of the total friction losses in the combustion engine. This paper describes part of a larger program to reduce wear the set working parts (piston, piston ring and bearing surface). The project is implemented through the development of new designs of piston rings with anti-wear coating that contains synthetic diamond in the form of loose embedded in a coating of chromium (PRS). The aim of the authors was to present the methodology used to compute characterized by a particular procedure. In practical use FEM software is used and the FVM. Developed and implemented Piston Rings Calculation Module is compatible with the idea of numerical computational methods is to say: functionally consists in carrying out a calculation of the desire to achieve the exact solution (the nearest is real) by conducting and receiving intermediate solutions (the next).

9

The impact of the energy state of the surface of friction pairs on the friction and wear in internal combustion engines

Borkowska J., Kaźmierczak A., Krakowian K., Cienciała M., Skorupa P., Łoza Ł.

Journal of KONES

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2015

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Vol. 22, No. 4

37--41

EN

The elements creating a friction pairs are described to be very difficult in terms of defining all optimal parameters in an unequivocal way. The research on stability of friction pairs is focused on the surface and the top layer of surface in the parts concerned. The main goal is to find new design solutions and materials, thereby achieving one million kilometers of mileage to main repair in the case of internal combustion engines. The biggest structural difficulties are noticeable in friction pairs where it can be observed sliding and returning motion, which is also connected with sealing function. A typical example of such pair is piston ring – cylinder sleeve in piston – rings - cylinder unit in an internal combustion engine. Engineers are currently seeking an additional factor, which would enable gaining the reduction of tangential force by reducing the friction coefficient in elements of friction pair during operations. The surface free energy may be such factor - it results from molecular structure and nature of the bonds between the molecules present in the material. Components of surface free energy determine the tribological properties of the material, which is reflected in the stability of the units. Energy state of the surface, which is connected with chemistry and characteristics in the material, is the first step to consider about the impact on wearing in internal combustion engine. This is the main topic of this article.

10

Review of possibilities of increasing the thickness of an anti-wear coating on piston rings by using specifically designed physical vapour deposition process

Skorupa P., Kaźmierczak A., Błasiński T., Borkowska J., Krakowian K., Łoza Ł.

Journal of KONES

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2015

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Vol. 22, No. 4

281--286

EN

The super-hard, anti-wear amorphic coatings based on carbon-like diamond (called DLC) show a promising direction in automotive industry, mainly in terms of decreasing friction coefficient in parts of internal combustion engine. However, the technology of producing DLC-coated parts, which is most often chemical vapour deposition (CVD) or physical vapour deposition (PVD) is proven to be still not perfect for achieving desired characteristics of the coating. The thickness of a coating is the main issue one should strive to improve, as the PVD methods produce films as thin as few micrometres. In such case, the coating is not only exposed to cracking, but also pitting is possible to happen. This is proven to be highly undesirable and unacceptable for this process. In addition, in case of thin films, the adhesion to the base is often too weak, despite the coating itself being extremely durable and hard. In this article, a theoretical ways to improve the process of coating are presented. The process itself is described, the achievable parameters are defined and the possible improvements are stated. The research made for the purpose of this article will be further exploited to design a process allowing creating the coating for testing of the best possible characteristics.

11

Pressure waves influence on performance of a pyrotechnically driven device

Górniak A., Kaźmierczak A., Włostowski R., Ptak M.

Journal of KONES

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2015

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Vol. 22, No. 3

21--27

EN

This paper contains an experimental investigation of a movable wall with variable shape response to a shock wave. Here, the shock wave was generated by a pyrotechnic gas generator used in the automotive industry. The test station consists on a pyrotechnic actuator in which the movable wall is expressed as a piston. This pyrotechnic actuator was specially design for such type of an investigation. Its design allows withstanding numerous tests without affecting the accuracy. What was under investigation here was the actuators piston stroke velocity and which, as it appeared, changes with respect to the various shape of the actuators interior as well as a corresponding to the barrier velocity total pressure existing within the expansion chamber of the actuator. The results shown here correspond to the flat surface as well as conical and concave cylinder bottom of the actuator. The conical and flat piston surface is considered as a reference for subsequent investigation because such a design is the most similar to the existing pyrotechnically driven designs. The experimental research proves that the performance of pyrotechnically driven devices is dependent upon the shock wave shaping.

12

Direct and indirect heat energy conversion into electricity

Cienciała M., Kaźmierczak A., Haller P., Krakowian K., Błasiński T., Borkowska J., Skorupa P.

Journal of KONES

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2015

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Vol. 22, No. 4

67--72

EN

Conversion of heat energy into electricity is described. Energy conversion is the process of changing one form of energy to another. There are two methods of conversion: direct, when heat energy is converted directly into electricity and indirect, when heat energy is converted into mechanical energy first and afterwards into electricity. A principle of direct method is thermoelectric effect that includes three separately identified effects: the Seebeck effect, the Peltier effect and the Thomson effect. In case of heat energy conversion into electricity, we are talking about Seebeck effect. For indirect method, first heat energy is converted to mechanical energy. The principle is gas compression and expansion due to temperature change that is used i.e.: steam engine, Stirling heat engine or polish engine WASE2. The engine is based on the fundamental physical phenomena. The next step is to convert mechanical energy into electricity. The principle is electromagnetic induction that produces an electromotive force across a conductor when it is exposed to a time varying magnetic field. Electromagnetic induction is used in i.e.: generators, alternators or American type generators.

13

State of shore and backshore on the basis of monitoring results for selected polish seashores

Boniecka H., Kaźmierczak A.

Biuletyn Instytutu Morskiego w Gdańsku

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2015

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Vol. 30, No. 1

150--163

EN

Aim of works on morphology and morphometry of the coastal zone is identification of qualitative and quantitative changes in the beach-dune strip and in the shoreface in conditions of their natural and anthropogenic transformations. As shore and backshore are essential elements reducing risks from the sea to the adjacent hinterland, this article focuses on evaluation of their parameters. Moreover, elements of the coast are described herein in detail. The research material used for the purposes of this article were records of bathymetric-tacheometric measurements of the Polish coast, made at consistent profiles evenly spaced every 500 m. The measurements did not cover the areas adjacent to the Bay of Gdańsk or the Lagoons. This article presents an analysis of the measurements of components of the coastal zone, which covered four morphodynamical areas (the Hel Peninsula, Jastrzębia Góra – Jarosławiec, Jarosławiec – Sarbinowo, and Sarbinowo – Międzyzdroje), twelve sandbar stretches (the Helska, Karniewska, Sarbska, Łebska, Długie, Gardno, Wicko, Kopań, Bukowo, Jamno, Resko, and Dziwnowska Spits) and thirteen cliff stretches (the cliffs in Chłapowo, Jastrzębia Góra, Rowy, Dębina, Ustka, Jarosławiec, Wicie, Sarbinowo, Ustronie Morskie, Śliwin, Trzęsacz, Pobierowo, and on Wolin Island). The basic linear parameters of the beach-dune and beach-cliff belt were read from 678 printouts of tacheometric profiles. A detailed analysis carried out in this manner made it possible for the endangered sections of the coast to manifest themselves. The obtained data are a basis for further comparative analyses, and assessment of the shore under conditions of implementation of the Act on the Protection of Sea Coasts.

PL

Celem prac nad morfologią i morfometrią strefy brzegowej jest poznanie jakościowych i ilościowych zmian zachodzących w pasie plażowo-wydmowym i na podbrzeżu w warunkach ich naturalnych i antropogenicznych przekształceń. W artykule skupiono się na ocenie parametrów brzegu i nadbrzeża, jako znaczących elementów redukujących zagrożenie przyległego zaplecza od strony morza. Ponadto opisano szczegółową charakterystykę elementów wybrzeża. Materiałem badawczym były zapisy pomiarów batymetryczno-tachimetrycznych polskiego wybrzeża, w stałych profilach rozmieszczonych co 500 m. Pomiary nie objęły swoim zasięgiem obszarów przylegających do Zatoki Gdańskiej czy zalewów. W artykule przedstawiono analizę pomiarów elementów strefy brzegowej, które objęły cztery rejony morfodynamiczne (Półwysep Hel, Jastrzębia Góra- -Jarosławiec, Jarosławiec-Sarbinowo oraz Sarbinowo-Międzyzdroje), dwanaście odcinków mierzejowych (Helska, Karniewska Sarbska, Łebska, Długie, Gardno, Wicko, Kopań, Bukowo, Jamno, Resko i Dziwnowska) i trzynaście odcinków klifowych (chłapowski, jastrzębski, rowski, dębski, ustecki, jarosławiecki, wicki, sarbinowski, ustroniomorski, śliwiński, trzęsacki, pobierowski i woliński). Na wydrukach 678 profili tachimetrycznych odczytano podstawowe parametry liniowe pasa plażowo-wydmowego i plażowo-klifowego. Tak przeprowadzona szczegółowa analiza wybrzeża pozwoliła na uwidocznienie zagrożonych odcinków. Uzyskane dane stanowią podstawę do dalszych analiz porównawczych i oceny stanu brzegu w warunkach wdrażania zapisów ustawy o ochronie brzegów morskich.

14

Module of a geodesic foliation on the flat torus

Kaźmierczak A.

Journal of Applied Mathematics and Computational Mechanics

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2014

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Vol. 13, nr 4

61--72

EN

We study properties of geodesic foliations on the flat, n-dimensional torus. Using the isomorphism of the Hodge star, we obtain some facts concerning compact totally geodesic surfaces (which are the leaves of geodesic foliations). We compute the p-module of a geodesic foliation. On the basis of these results, we derive a kind of reciprocity formula for the product of modules of two orthogonal foliations. We relate this product with the number of intersections of their leaves. We also obtain a formula for a product of modules of a finite number of geodesic foliations.

15

Opportunities of exhaust heat recovery and conversion to electricity

Cienciała M., Kaźmierczak A., Krakowian K., Błasiński T.

Journal of KONES

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2013

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Vol. 20, No. 4

63--70

EN

The maximum efficiency of the conventional spark ignition engine is 33%, in the case of diesel engines is 42%. The conclusion is that the energy contained in the fuel and "released" in the combustion process is converted into mechanical work only in a small degree. The rest of the energy is unfortunately lost by heat, friction, or used to drive the engine accessories. It should also be noted that these values are peak efficiency, which is achieved only when the engine works in optimal parameters. At most used parameters engines reach efficiency on the level of 10% to 25%. In modern cars with a hybrid powertrain are solutions that can improve the efficiency of conventional internal combustion engines. It is worth to notice that there are few ways to improve the efficiency of a reciprocating engine. The main technological trends on which research is underway are knock ignition and heat recovery from the exhaust. More development seems to be the second solution, because it can be used to design new engines such as the replacement of the alternator on the generator of electricity from exhaust heat. Besides, it will be possible to adapt these systems to in-use units, which improve the energy balance of riding vehicles. In article, you will find information of literature analysis for exhaust heat recovery and conversion to electricity solutions, computerized exhaust modification with flow calculations, real modification, test bench creation, researches and scores, analysis.

16

Numerical investigation of a movable wall response on a flame propagation

Górniak A., Kaźmierczak A.

Journal of KONES

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2013

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Vol. 20, No. 2

135--141

EN

This paper contains a description of a shock wave (called a flame when the deflagration is considered) propagation pattern impact on a motion of a barrier. Here, the numerical research was conducted on a model of a pyrotechnic actuator, hence, the piston is understood as a movable barrier. The processes occurring within the pyrotechnic actuators after ignition of a pyrotechnic propellants have been explained. The investigations are focused on the dependence of a shape of the actuator’s combustion chamber and the piston stroke time. It appears that the appropriate design of the combustion chamber can decrease the time required for a piston total stroke using this same type of a propellant. The visualization of the flame occurring due to ignition of the propellant is crucial for understanding the dependence between the construction of the actuators interior and the piston stroke time. Therefore, the approach of simulating numerically the flames aroused. The simulation was conducted on a full scale 3D model of a pyrotechnic actuator which is a detail representation of a real object on which the verification test will be conducted. However, only the flame propagation was considered here. The material of an actuators members was not investigated, hence the AUTODYN solver considered them as a single rigid bodies with its own mass and inertia.

17

Modern diesel engines NOx particles emission

Krakowian K., Kaźmierczak A., Wdowikowska A.

Journal of KONES

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2013

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Vol. 20, No. 3

245--250

EN

Exhaust gases recirculation systems (EGR), together with catalytic reactors, are commonly installed in modern piston combustion engines. Their purpose is to reduce the amount of nitrogen oxides (NOx) emitted in fumes. The need for this reduction takes its source from introducing more rigorous EURO standards, which are treating about maximum levels of NOx, HC and particulates produced, as a side effect of engine's operation. Applied exhausts recirculation circuits can be roughly characterized by a principle, that a part of exhaust gases is redirected (through a cooler) and reaches a special valve. This valve, respectively to engine's current load and speed, drives more or less exhaust to suction manifold. The position of the valve determines the system’s overall efficiency, but also differentiates the amount of toxic gases and smoke produced by each of the engines cylinders. Recent research have focused only on the overall efficiency of recirculation systems, representing it by measuring the total amount of NOx particles emission from exhaust pipe. However, the quantity of exhaust gases that is reaching each cylinder can be negatively dependant on EGR valve’s physical position in the circuit. This happens due to the fact that combusted loads have different proportions of charged air and fuel. For estimating the difference among each of the loads, and in the same time, indirectly, in equal emission of NOx from corresponding cylinders, a research was carried out on a model VW 2.0 TDI engine, equipped with standard, factory mounted, exhausts gases recirculation circuit. Measurements of toxic emissions were executed with regards to thirteen-point ESC (European Stationary Cycle) test.

18

Experimental studies of a moveable wall to a shock wave

Górniak A., Kaźmierczak A.

Journal of KONES

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2013

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Vol. 20, No. 3

145--151

EN

This paper explains the experiment conducted in order to reveal the response of a movable wall on a shock wave generated by ignition of a pyrotechnic gas generator dedicated for the automotive industry. This same kind of a pyrotechnic gas generator was used in each test. The test station consists on a pyrotechnic actuator in which the movable wall is expressed as a piston. The pyrotechnic actuator was specially design for such type of an investigation. Its design allows withstanding numerous tests without affecting the accuracy, and it is prepared to pressure measurement in three locations on the cylinder. However, here only the pressures measured in the vicinity of a cylinder bottom are under deliberation. This paper focusses on a shape of the piston influence on its movement characteristics (i.e. stroke velocity and acceleration). The experiment has shown that there is an influence of the shape of the movable wall on its movement characteristic. Furthermore, the experiment explained here constitutes a comparison of a piston velocity and acceleration with a flat and concave front surface. The dynamic pressure measurement have proven that the reflected shock wave increases its speed affecting the piston movement.

19

Evolutionary algorithms for propellants parameters identification

Górniak A., Kaźmierczak A.

Journal of KONES

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2013

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Vol. 20, No. 2

127--133

EN

This paper presents the possibility of the parametric identification of an unknown low energy explosive basing only on its ballistic curve using advanced optimisation algorithm. What was under investigation here was the approach of an explosive replication for the numerical investigation of ANSYS AUTODYN solver. The emphasis was given here for the propellants used in the automotive safety devices. The results of closed bomb testing was compared with its numerical representation. The required parameters to develop a new numerical model of an explosive was identified with the aid of evolutionary algorithm. In order to perform a parametric identification a mathematical model of considered phenomenon is required. Hence, this paper contains a mathematical model of a deflagration process which was the basis for the evolutionary algorithm. The algorithm verified a variety of parameters until the objective function is obtained. In the case of this paper the objective function was a ballistic curve of an unknown explosive which combust under deflagration regime. The results obtained with this method shows good agreement with the closed bomb test of the propellant. Furthermore, advanced optimisation tools such as an evolutionary algorithms, in oppose to most of other optimisations algorithms, enables to find a global optimum. However, the identified function here was found to be unimodal.

20

Energy costs savings by use of micro - CHP units in domestic households

Błasiński T., Kaźmierczak A., Krakowian K., Cienciała M.

Journal of KONES

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2013

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Vol. 20, No. 3

41--46

EN

Prices of thermal and electric energy delivered to households are constantly increasing, and it will probably not change over the next few years. Due to this fact, people had been forced to find different ways to reduce costs of buying energy. The paper contains description of the most popular systems which are already in use from many years and some innovative systems which are implemented now, or which may be probably installed in nearly future – for example: internal combustion engines, Stirling engines, proton exchange membrane fuel cells, gas turbines, engines with Rankine cycle, etc. Each of mentioned above appliances is necessary to create CHP system which advantages and disadvantages are also described. In this publication, the most promising units have been compared to show their performance, flexibility, profitability and range of using ability. In this paper, approximate money and energy savings that may occur by using modern solutions compared to traditional systems are also shown. As always, during design and development of this kind of devices, there are a lot of problems related to various issues. Main problems and potential solutions have been also presented in this article. In summary further research, directions are suggested due to improve performance of this kind of systems.