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1

Properties of novel composite alloys used for the engine pistons

Kowalski M., Jankowski A.

Journal of KONES

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2017

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Vol. 24, No. 4

109--116

EN

The article presents the results of the investigations cover novel composite silumins with new alloying additives, such as chromium and molybdenum (not yet used in this type of silumin) and increased content of nickel and copper. The samples strength tests were performed at room temperature (20°C) and at elevated temperatures (up to 350°C), and were carried out using the strength machine, equipped with the special climate chamber. The dimensional stability of the new aluminum alloy was investigated using the precision dilatometer. This device allows one to register and record the sample dimensions as a function of temperature, during sample heating and cooling. During the DTA crystallization process investigations, derivative curves have been determined, that allows the analysis of the solidification process and the analysis of the heat transfer process in the sample structure and phase transformations. In the article shows the derivative curve and representative microstructures, and characteristic temperatures for the conventional AlSi12 alloy and novel composite alloy. All research results indicated that the newly developed composite aluminum alloy has far better parameters than aluminum alloys used previously for pistons of the internal combustion engines. This article concludes with a summary of the advantages of the new composite alloys.

2

Researches of novel composite pistons for combustion engines

Jankowski A.

Journal of KONES

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2013

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Vol. 20, No. 4

141--146

EN

Novel composite material was worked out based on experiences and researches realized in the Institute of Aviation, the Lodz Technical University and PZL WOLA Company. Actually applied silumins on the pistons secure them high-quality for durability, low Rm and HB values at increased temperature, high hysteresis of the coefficient a during heating and cooling, high clearance between the piston and the cylinder, increased oil consumption, blowthrough and obtainment relatively low-power engine. Thereby works concerning elaborations of novel composite material based on the standard silumin with better from at present applied on the piston properties are presented. Novel composite material on the pistons has mechanical properties in the ambient temperature: Rm ≥ 400 MPa; Rp0.2 ≥ 330 MPa; A5 ≥ 3.5%; HB ≥ 130 and in the temperature 250°C: Rm ≥ 320 MPa; Rp0.2 ≥ 240 MPa; A5 ≥ 5%; HB ≥ 90. Metallographic and ATD researches, the researches of the hardness, the researches of Rm, Rp0.2 and A5, the researches of the coefficient of thermal expansion "α", engine researches were performed. Curves ATD and the microstructure the alloy are presented. Test results of the S12-U diesel engine engine are introduced too.

3

Researches novel materials on the pistons with low hysteresis to combustion engines

Sieminska B., Slawinski Z.

Journal of KONES

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2012

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Vol. 19, No. 4

549-554

EN

The researches were carried out at the use of the precise dilatometer of the firm BAHR 802/801. The device makes possible the registration of changes of measurements of the sample in the function of the temperature. Measurements in the simpler and differential are possible. Heating and cooling is performed in the special device, which realizes the programme temperature, controlled computer. Changes of dimensions are measured with an inductive sensor. Samples were placed in the quartz-pipe and changes of their length were transferred by quartz-rods. The temperature of tested material was measured by means of the Pt-PtRh thermocouple. Material on the pistons has a fundamental meaning for the value of the clearances between the cylinder and the piston. Too small clearness between the piston and cylinder on the cold engine cannot be applying, because during the work of an engine it would be able to occur seizing of an engine. From here, also the large resistance on seizing of material of the piston is essential. Investigated composite materials performed based on piston-silumins AK12 and AK18 in which a composite addition was silicon carbide (SiC) and ferric sulphide (FeS).

4

Zużycie tłoków silnikowych – charakterystyka mikrostrukturalna materiałów wykorzystywanych do ich produkcji

Walczak Mariusz, Bieniaś Jarosław, Stradomska Bogna, Jankowski Adam, Bielecki Daniel

Zeszyty Naukowe WSEI. Seria Transport i Informatyka

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2011

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T 1, nr 1

59--72

PL

Dynamiczny rozwój motoryzacji wyznacza nowe kierunki w zakresie inżynierii materiałowej, stawiając konstruktorom i technologom początku XXI wieku potrzebę intensywnego poszukiwania nowych materiałów konstrukcyjnych, zapewniających podwyższenie trwałości eksploatacyjnej elementów składowych silnika. Obserwowana tendencja w motoryzacji do podwyższanie osiągów silników wskazuje, że efektywność działania tłoków silników spalinowych zależy w głównej mierze od trwałości materiałów stosowanych do produkcji tych elementów jak i warunków pracy samego silnika. Jednymi z najbardziej perspektywicznych, a zarazem nowoczesnych materiałów są metalowe materiały kompozytowe. W artykule przedstawiono uszkodzenia tłoków silnikowych powstałe w wyniku przeciążeń cieplnych oraz mechanicznych. Ponadto scharakteryzowano mikrostrukturalne właściwości wybranych metalowych materiałów kompozytowych o osnowie stopu aluminium zbrojonych: popiołami lotnymi (fly ash) cząsteczkami grafitu i cząsteczkami SiC (F3S.20S), a także monolitycznego stopu AK12.

EN

Dynamic development of automotive sector determines new tendencies in the area of material engineering, creating for the engineers and technologists of early twenty-first century the need for intensive search for new structural materials, providing increased service life of engine components. The observed trend in the automotive industry for increasing engine performance indicates that the effectiveness of the internal combustion engine piston depends largely on the durability of materials used to manufacture this items, as well as on working conditions of the engine itself. One of the most promising, and modern materials are metal composite materials. The paper presents examples of damages to engine pistons caused by thermal and mechanical overload. Microstructural properties of selected metal composite materials with aluminum alloy matrix reinforced with fly ash, graphite particles, SiC particles (F3S.20S) and the monolithic alloy AK12.

5

Composite alloy for IC engine pistons

Jankowska-Sieminska B., Jankowski A., Sławinski Z.

Journal of KONES

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2010

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Vol. 17, No. 2

159-166

EN

Aluminum is the most popular matrix for the metal matrix composites The Al alloys are attractive due to their low density, their capability to be strengthened by precipitation, their good corrosion resistance, high thermal and electrical conductivity, and their high damping capacity. The characteristics of metal matrix composite materials are determined by their microstructure and internal interfaces, which are affected by their production and thermal mechanical treatment. Investigations to improve the combustion piston engines arę leading to improve the working process performance by increase ofits parameters, especially the average temperature of the thermodynamic cycle. New piston consists of two parts manufactured of standard and composite materials are presented in the paper. Composite alloy has chemical composition of short fibre with Al2 O3 was following, in the mass percentage: 96% Al2 03, 4%, SiO2. As the binder the colloidal silica was used in quantity 5%. The volume of fibres in the insert was 22 plus or minus 2% by volume. Bending strength of the insert was 0.5 MPa. Temperature and stresses distribution in standard piston and different versions of composite pistons are introduced in the paper. The paper presents the resistance of investigated materials on thermal shocks. Experimental veriflcation of manufactured composite pistons in the engine proved the larger exhaust temperaturę for about 20-70°C, in comparison with the engine with standard pistons (that gives the greater effectiveness of turbo charging application), proved the lowering of a individual volume of gases blow-bys to the crankcase, the lowering of noise level, larger resistance on thermal loads.

6

Preliminary research no vel composite materials with small hysteresis and high functional parameters for combustion engines pistons

Siemińska-Jankowska B.

Journal of KONES

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2009

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Vol. 16, No. 1

447-452

EN

Pistons of internal-combustion engines are the most loaded elements of internal-combustion engines, belong to these specialistic elements, which have essential influence on the ecological properties of engines, their durability and reliability. The object of paper is pistons manufactured from the standard material and from new research alloy. The investigations were performed with dilatometer permitting on the registration of changes of the dimensions of sample in the function of temperature and time. The measurements are possible in straight system and in differential system. Exemplary results of investigations are presented in the paper. During the piston heating, period preutectic phases succumb the partial dissolution in solid solution a, but in the cooling process they secrete again. As a consequence the piston partial deformation occurs, which by result is gradual growth of difference between its expansibility during the warming and contraction in the process of cooling (so-called hysteresis occurs). The characteristics of the new piston silumin alloys give possibility of dearances minimalization and the obtainments of a correct engine performance in the full range of engine rotational velocities and loads. The effect are the decrease of the oil expenditure, the decrease of the emission of hydrocarbons in exhaust gases, the decrease of blowbys to crankcase, the decrease of the expenditure of piston rings grooves wear and the piston skirt wear, the decrease of the piston deformation and the increase of engine durability and reliability.

7

Coefficient of thermal expansion as a component quality estimation of alloys on pistons of combustion engines

Sieminska B.

Journal of KONES

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2009

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Vol. 16, No. 4

575-583

EN

The aim of realized works in the area of materials on pistons is: low thermal expansion, small differences of coefficient of thermal expansion between heating and cooling, high stiffness at elevated temperatures, high hardness and wear resistance. Changes in thermal expansion coefficient during heating and cooling may be very large, as well as during subsequent cycles of heating and cooling of an internal combustion engine pis ton with respect to standard silumin alloys usedfor pistons of internal combustion engines. The paper presents: coefficient of linear expansion a for the AlSi standard alloy, coefficient of linear expansion a for the AlSi alloy with the apositive differences between cooling and heating, coefficient of linear expansion a for the AlSi alloy with the a negative differences between cooling and heating, coefficient of linear expansion a for the AlSi alloy with the apositive and negative differences between cooling and heating, coefficient of linear expansion a for the AlSi alloy with the apositive, negative and positive differences between cooling and heating, coefficient of linear expansion a for the AlSi alloy with the very small a differences between cooling and heating, coefficient relative elongation as afunction of temperature with the positive elongation differences between cooling and heating, coefficient relative elongation with the very small elongation differences between cooling and heating, coefficient the course of derivative as a function of temperature (T) during heating and cooling with the positive elongation differences.

8

Investigations of strength, thermal expansion and engine of novel pistons for combustion engines

Siemińska B.

Journal of KONES

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2008

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Vol. 15, No. 3

471-478

EN

Pistons of internal-combustion engines work in the conditions of high mechanical and thermal loads. The typical alloy materials applied on pistons of internal-combustion engines have inadequate parameters for such applications. It mainly refers to the fatigue strength of the mechanical and thermal character and to the thermal shocks. In relation with fact that the piston of internal-combustion engine has unsymmetrical shape, that in every case of the piston temperature increase the unequal deformations appear and stresses related with this, what causes fatigue loads of the piston structure. The paper presents special demands, which pistons of contemporary of internal-combustion engines must fulfil with respect to strength, thermal and useful properties, mirrored in the engine work parameters, like engine oil consumption, fuel consumption, noise, gas blow by to the crankcase and the emission of toxic exhaust elements, mainly hydrocarbons. One turned attention on the new material that can be used in manufacture of pistons for the internal-combustion engines, which is the carbon material. In the article the results of research for the mechanical, thermal and engine properties are submitted for the pistons manufactured from a new material. On the emphasis deserve fact, that the application of new materials permits on the obtainment of the small difference in the coefficient of linear thermal expansion during the heating and the cooling, that will bring many profitable effects of both functional and useful nature.

9

Does "downsizing" limit the durability of piston-cylinder assembly?

Iskra A.

Journal of KONES

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2008

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Vol. 15, No. 3

195-200

EN

Internal combustion engines purposed for passenger car drive are not perfect but there is no alternative drive yet that could replace IC engine in noticeable percentage. However, among IC engines there is a tough competition between two kinds of ignition. At present, a gasoline engine subjected to the "downsizing" [4] is the only alternative to very popular diesels. Such engine shows specific fuel consumption similar to diesel maintaining the principal advantages of spark engine. The fundamental advantage is generating the maximum torque at about 1500 rpm and keeping it up to 3500 rpm for an engine operating within 850 to 5000 rpm range. However, such advantageous characteristics of torque can cause a limited durability of the piston-cylinder assembly. High torque at low speed creates unfavourable conditions of collaboration between the upper compression ring and cylinder surface. Presented paper analyzes the oil film parameters between the upper compression ring and cylinder liner of ,"downsizing" engine and compares these parameters with analogue ones of a regular gasoline engine of comparable power. High ring to cylinder pressure caused by gaseous forces at low piston speed leads to two disadvantageous phenomena, namely the drop in oil film minimum thickness and an increase in friction force. The paper presents an analysis of both parameters and the assessment of their scale. A minor effect of "downsizing" on ring-cylinder friction power has been established, which is confirmed by the producers' data concerning fuel consumption [4].

PL

Tłokowe silniki spalinowe napędzające samochody osobowe nie są rozwiązaniami idealnymi ale jak na razie nie istnieje konkurencyjny silnik, który mógłby zastąpić w zauważalnym procencie ten - niepozbawiony wad -rodzaj napędu. Istnieje natomiast ostra konkurencja między dwoma rodzajami zapłonu w tłokowych silnikach spalinowych. Aktualnie może ograniczyć ekspansję silników o zapłonie samoczynnym (ZS) silnik o zapłonie iskrowym (ZI) poddany procesowi tzw. "downsizing'u" [4]. Taki silnik wykazuje jednostkowe zużycie paliwa zbliżone do silnika ZS zachowując podstawowe zalety silnika ZI. Podstawowa zaleta to generowanie maksymalnego momentu obrotowego już od prędkości obrotowej ok. 1500 [obr/min] i utrzymywanie tego momentu do 3500 [obr/min] dla silnika pracującego w zakresie 850-5000 [obr/min]. Taka, bardzo korzystna charakterystyka momentu silnika wykorzystywanego do napędu samochodu, może jednak prowadzić do ograniczenia trwałości zespołu tłok cylinder. Duża wartość momentu przy niewielkiej prędkości obrotowej stwarza niekorzystne warunki współpracy górnego pierścienia uszczelniającego z gładzią cylindra. W artykule przeanalizowano parametry filmu olejowego między górnym pierścieniem uszczelniającym a gładzią cylindra silnika "downsizing'owanego" oraz porównano te parametry z analogicznymi parametrami klasycznego silnika ZI o zbliżonej mocy znamionowej. Duży nacisk pierścienia na gładź cylindra wywołany siłami gazowymi przy niewielkiej prędkości ruchu tłoka powoduje dwa niekorzystne zjawiska, a mianowicie zmniejsza się minimalna grubość filmu olejowego oraz zwiększa się siła tarcia. W artykule przeanalizowano oba parametry a zarazem oceniono skalę przytoczonych zjawisk. Potwierdzono niewielki wpływ "downsizing'u" na moc tarcia pierścieni o gładź cylindra, co potwierdzają dane producentów dotyczące zużycia paliwa [4].

10

Wybrane właściwości mechaniczne materiału tłoka kompozytowego do silnika spalinowego

Rudnik D., Sobczak J.

Kompozyty

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2002

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R. 2, nr 5

342-347

PL

Dynamiczny rozwój motoryzacji oraz wciąż zaostrzane kryteria dotyczące poprawy szeroko rozumianej ekonomiczności i ekologiczności pojazdów spowodowały, że stosowanie tradycyjnych materiałów w budowie samochodów okazało się niewystarczające. W związku z tym konieczne stało się wprowadzenie w konstrukcji pojazdu nowoczesnych materiałów, które mogłyby sprostać wciąż rosnącym wymaganiom. W przypadku tłoków do silników spalinowych właściwości mechaniczne materiału są niezmiernie istotne przy określaniu parametrów konstrukcyjnych tego elementu pojazdu. W niniejszej publikacji przedstawiono wyniki badań wybranych właściwości mechanicznych metalowych materiałów kompozytowych o osnowie stopu aluminium zbrojonych dyspersyjnie: popiołami lotnymi (kompozyty ALFA*), cząsteczkami grafitu (niklowanymi) i cząsteczkami SiC (F3S.20S) oraz lokalnie preformą z włókien krótkich Al2O3, a także, dla porównania, monolitycznego stopu AK12. Wyniki badań twardości, wytrzymałości i udarności pozwoliły na stwierdzenie, że badane kompozyty charakteryzują się znacznie wyższym poziomem uzyskiwanych właściwości niż stop AK12, dotychczas powszechnie używany do produkcji tłoków. W związku z tym można przypuszczać, że zastosowanie materiałów kompozytowych pozwoli na takie zmiany konstrukcyjne samego tłoka, a w efekcie całego silnika, które przyniosą oczekiwaną poprawę parametrów użytkowych samochodu.

EN

The dynamic development of automobile industry and continuously growing criteria concerning economic and ecological management of automobiles contributed to the fact that the traditional methods of automobile designing have turned out to be insufficient. Therefore, it become essential to introduce new materials, which would be able to meet more and more requirements. The mechanical characteristics for combustion engine pistons, such us tensile properties at room and elevated temperatures, fatigue and impact characteristics, and hardness are extremely important for reasonable and high performance designing. In this paper some selected mechanical properties for different particle reinforced aluminum matrix composites materials containing fly ash (ALFAŽ), nickel coated graphite and silicon carbide (F3S.20S) have been investigated along with monolithic and locally reinforced with alumina short fibers AlSi12CuNiMg alloy. The results of hardness measurements (Fig. 1), selected strength properties at room (Fig. 2 and Tab. 1) and elevated temperature (Fig. 3), impact strength (Tab. 2) showed the advantages of new materials compared with traditional ones, especially AlSi12CuNiMg monolithic alloy widely used for production of IC engine pistons. Therefore, it may be conducted, that the adoption of composite materials will contribute to the construction changes of the pistons, and as a final results to the pistons for new engines, which will bring the anticipated improvement of the car.

11

Próba podwyższenia odporności na zmęczenie cieplne powierzchni tłoków silników spalinowych.

Gardyński L., Weroński A.

Inżynieria Materiałowa

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2000

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R. XXI, nr 6

283-288

PL

W pracy przedstawiono warunki pracy tłoków silników wysokoprężnych, zwr

EN

The paper presents the brief study of self-ignition pistons' operating