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Advantages of using composite alloys for internal combustion engine pistons

Kowalski Mirosław, Jankowski Antoni

Archives of Transport

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2020

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Vol. 55, iss. 3

85--94

EN

Combustion engine pistons are subject to variable mechanical and thermal loads, and to variable deformations. The article presents the possibilities of using novel composite alloys for the construction of pistons for combustion engines. The novel alloys make it possible to meet high demands, especially for highly load designs, which practically cannot be met by conventional alloys used so far. These high requirements relate to the weight of the pistons, high temperature strength, alloy crystalline structure, abrasive wear resistance, dimensional stability. The requirements for pistons have an impact on the durability of the engine's operation, the level of noise emissions; exhaust gas blow-by into the crankcase, the level of emitted toxic exhaust components, mainly hydrocarbons. The research covered metallography (chemical composition, microstructure), material strength, abrasive wear, and thermal expansion. Investigations of the alloy crystallization process during casting were carried out using the Differential Thermal Analysis (DTA) method. The castings were used for metallographic tests. The strength of the samples was tested at room temperature (20°C) and elevated temperature (up to 350°C) on a testing machine equipped with a special climatic chamber. In particular, the article presents Thermal Derivative Analysis curves and representative microstructures of conventional AlSi12 alloy and the novel composite alloy; dependence of the tensile strength versus temperature for the samples of the novel alloy with various nickel content 2% and 4 %; comparison of the tensile strength for conventional alloy and the novel alloy at ambient and 250°C temperature; comparison of abrasive wear of samples, made of novel aluminium alloy and different cast iron; course of the linear expansion coefficient versus temperature for the conventional AlSi12 alloy with incorrect heat treatment; course of the linear expansion coefficient versus temperature for one of tested silumin alloy which expansion coefficient during sample cooling is smaller than during sample heating; course of the linear expansion coefficient versus temperature for the novel composite silumin alloy, after correct heat treatment. The great benefits of using this novel alloy and the introduction of novel alloying elements (in-Situ) have been confirmed in engine research.

2

Optymalizacja parametrów toczenia rowka pod pierścienie tłokowe

Lisiak P., Twardowski P., Wojciechowski S.

Mechanik

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2016

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R. 89, nr 8-9

1024--1025

PL

Praca dotyczy optymalizacji procesu toczenia rowków pod pierścienie tłokowe. Badania obejmowały dobór prędkości skrawania vc i posuwu f umożliwiający poprawę efektów ekonomicznych toczenia. Przeprowadzono optymalizację procesu ze względu na trwałość ostrza w celu minimalizacji kosztów jednostkowych Kj oraz maksymalizacji wydajności obróbki W.

EN

This work concerns the optimization of cutting parameters for the groove turning of piston rings. The research included the selection of cutting speed and feed per tooth values enabling the improvement of turning economics. The tool life optimization was carried out in order to minimize machining unit costs and maximize the productivity.

3

Some effects of applying a new type of pistons for SU12-U diesel engine

Jankowski A.

Journal of KONES

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2016

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Vol. 23, No. 4

167--174

EN

In the task of research and development of internal combustion engines, the strong emphasis is placed on reducing emissions of harmful substances in exhaust gases, which include carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM, PN); while maintaining a high engine performance and, above all, adequate: power, fuel consumption, noise. One of the possibilities to reduce emissions of HC and engine working noise is to reduce the clearance between the piston and the cylinder liner. This is possible only, when the permanent deformations of the piston are reduced, which result from rapid piston temperature changes (thermal shocks). The newly developed composite aluminum alloy is characterized by high strength parameters and low dimensional hysteresis during repeated heating and cooling. The S12-U engine pistons are made of this material, and they had a slightly larger nominal diameter than the standard pistons. They were then mounted in the engine. The engine was tested on a test stand with the modern, accurate measuring equipment. Test results show, that the HC and CO content in the exhaust gas has been reduced, exhaust gas blowby to the crankcase declined, smoke emission was reduced and engine lubricating oil consumption was also reduced. Analysis of test results indicates that this has been achieved, mainly by reducing the clearances between the piston and the cylinder. The article provides detailed test results, mainly in the form of charts, on which one can compare the results, achieved by the engine with new material pistons with results of the same engine, but with the standard pistons.

4

Dilatometric researches of novel alloy for combustion engine pistons

Żurek J., Slawinski Z., Jankowski A.

Journal of KONES

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2016

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Vol. 23, No. 3

585--596

EN

The article presents dilatometric research results of composite alloy (in-situ) for combustion engines piston. Researches were performed with a precise dilatometer. Alloy's research test stand and test results including relative elongation, course of derivative of dimension increasing versus time with phase transition and course of coefficient of linear thermal expansion α for composite alloy versus temperature are presented in the article. Novel composite alloy allows getting a minimum difference of the coefficient of linear thermal expansion α during heating and cooling. In particular, the chemical composition of the novel composite silumin alloys; ATD of standard alloy – silumin Ak12 and novel composite alloy; schema of research stand and view of the measuring-head of the extension; course of the coefficient of linear thermal expansion α versus temperature during heating and cooling for the standard alloy and novel composite alloy; course of the relative piston elongation ΔL/Lo versus temperature during heating and cooling for the standard alloy and novel composite alloy; course of the derived function of the extension in relation to time dL/dt versus temperature for the standard alloy on pistons and novel composite alloy; course of the relative elongation in function of time during ageing of composite alloy at the temperature of 200°C with two-stage ageing process; course of the relative elongation in function of time during ageing of composite alloy at the temperature of 200°C for the first stage and second stage are presented in the article.

5

Numeryczna analiza procesu plastycznego kształtowania odkuwki tłoka silnika spalinowego ze stopu aluminium 2618A

Tomczak J., Maciejczak D.

Rudy i Metale Nieżelazne

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2011

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R. 56, nr 10

521-526

PL

W artykule przedstawiono wyniki analizy numerycznej procesu kucia odkuwki tłoka motocyklowego silnika spalinowego ze stopu aluminium w gatunku 2618A. Proces zamodelowano w dwóch wykrojach matrycujących zamkniętych na prasie hydraulicznej. Analiza numeryczna procesu przeprowadzono opierając się na metodzie elementów skończonych (MES), wykorzystując komercyjny pakiet oprogramowania DEFORM-3D w wersji 10.0. Symulacje prowadzono w warunkach przestrzennego stanu odkształcenia, w trakcie których wyznaczono geometrie przedkuwki i odkuwki tłoka. Określono również rozkłady odkształceń oraz przebiegi sit kształtowania. Omówiono również sposoby wytwarzania tłoków stosowanych w silnikach spalinowych oraz wpływ zastosowanej metody kształtowania na ich wytrzymałość. Opisane rezultaty badań numerycznych potwierdzają możliwość wytwarzania odkuwek tłoków stosowanych w silnikach spalinowych metodami obróbki plastycznej.

EN

This paper presents the results of numerical analysis of forging process of a part of a motorcycle combustion engine piston from aluminum alloy 2618A.This process was modeled in two close die impressions on a hydraulic press. The numerical analysis of the process was made basing on finite element method (FEM), using the commercial software DEFORM-3D in version 10.0. Simulations were made in conditions of three dimensional state of strain. During simulations the preform geometry and geometry of the piston forging were determined. Strains distributions and forming forces course were also given. The ways of manufacturing of pistons used in combustion engines and the influence of the applied forming method on their durability were discussed. At present, in majority of cases, combustion engines pistons are manufactured by means of casting, which is unfavorable for their durability. One of the ways of increasing pistons durability and decreasing their mass is appropriate forming of the inner structure, which can be obtained in the result of the semi-finished part metal forming. The discussed results of numerical research confirm the possibility of manufacturing of pistons forgings applied in combustion engines by means of metal forming methods.

6

Some problems pistons made from composite materials with small hysteresis to combustion engines

Jankowska-Sieminska B.

Journal of KONES

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2011

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Vol. 18, No. 3

123-128

EN

Novel composite ma hysteresisterials on the pistons are characterised that they occur in them multiple intermetallic phases which crystallize in the high temperature, before crystallization of the alfa+beta (Al+Si) eutectic. For forming of pre-eutectic phases, chromium and molybdenum are introduced to silumins, and for derivation of multiple increased concentration of nickel and copper and decreased concentration of magnesium are accomplished. On the basis of evaluations of mechanical and thermal loads of combustion engines pistons applying essence of composite materials of combustion engines pistons, as well requirements for combustion engines pistons, especially high loaded engines are expressed. Test results of hardness, influence of temperature of casting, test results of mechanical properties, friction coefficient and coefficient of thermal expansion are presented in the paper. The special attention devoted to so called hysteresis coefficient of thermal expansion and hysteresis of the relative elongation in function temperature and time. Courses of coefficient of thermal expansion for standard and composite material are presented. Differences of the a coefficient during heating and cooling in function temperature are relative to kind of heat treatment. Two-stage heat treatment is beneficial for the obtainment small values of the a coefficient.

7

Logistyczne zabezpieczenie seryjnego montażu tłoków silnika spalinowego

Streubel A., Kuran M., Kuprowska I.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2010

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z. 79 [273]

45-49

EN

In the paper problems concerning large series assembly of combustion engine piston and problems connected with assurance of supplies of components such as rings and piston pin are presented. Ways of suppliers classification from the point of view of delivered elements quality are described. Problems connected with stock of hand planning to assure assembly process continuity is presented too.

8

Logistyczne zabezpieczenie seryjnego montażu tłoków silnika spalinowego

Streubel A., Kuran M., Kuprowska I.

Technologia i Automatyzacja Montażu

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2010

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nr 3

41-43

EN

In the paper problems concerning large series assembly of combustion engine piston, and problems connected with assurance of supplies of components, such as rings and piston pin are presented. Ways of suppliers classification from the point of view of delivered elements quality are described. Problems connected with stock of hand are presented to assure assembly process continuity.

9

Technological applications of laser ablation in combustion engine pistons

Napadłek W.

Journal of KONES

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2008

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Vol. 15, No. 3

382-388

EN

The principles and possible applications of laser ablation technology in combustion engines pistons were described. Laser ablation removal of carbon deposits and other products of pistons using from pistons bottom was presented. The process of sequence removal of the deposits was controlled, so the pistons were not damaged. Nd: YAG laser with 10 Hz pulse work and wavelength X-- 1064 nm was applied during the process. In the laboratory experiments the deposits were removed from aluminum Akl12 and from ceramics on the basis of zirconium, sputtered on the pistons bottom as a thermal barrier (TBC). The exposition time of laser beam ranging from 10 to 20 ns was applied. Furthermore variation of such important parameters of laser treatment like energy density, beam scanning rate, impulse covering rate was applied, resulting with a set of parameters applicable for lab and even industrial scale. After deposits removal from surface layer, many micro- and macro cracks were noticed. The cracks created a net-like pattern, which was a result of cyclic heat-shock present during 400 hours long endurance test of combustion engine. The laser technique is an alternative for other methods because of its ecological reasons. It is also very precise and can be easily automated. It can be also applied in diagnosis, verification and also as a surface layer pretreatment for such a processes like thermal sputtering, or deposition of composite layers in important areas of pistons.

PL

Opisano istotę oraz możliwości zastosowań technologicznych ablacji laserowej dla tłoków silnika spalinowego. Przedstawiono wybrane wyniki badań własnych w zakresie ablacyjnego usuwania nawarstwień, głównie w postaci nagaru na denku tłoka oraz innych osadów będących produktami eksploatacji tłoków. Usuwanie sekwencyjne nawarstwień realizowane było w sposób kontrolowany, dzięki temu nie następowało uszkadzanie podłoża tłoka. Ablacyjne oczyszczanie laserowe realizowane było przy użyciu lasera Nd: YAG o pracy impulsowej 10 Hz oraz długości promieniowania laserowego X = 1064 nm. W eksperymentach laboratoryjnych usuwano ww. nawarstwienia osadzone na podłożu ze stopu aluminium Ak12 oraz ceramiki na bazie cyrkonu, natryskanej na denko tłoka jako bariera termiczna (TBC). Stosując czas ekspozycji wiązki laserowej ok. 10 -20 ns oraz różne parametry obróbki laserowej: gęstość energii, prędkość skanowania wiązki, stopień przykrycia impulsów dobrano właściwe parametry obróbki, które mogą być stosowane nie tylko w warunkach laboratoryjnych, ale również w skali przemysłowej. Po usunięciu nawarstwień w warstwie wierzchniej barierowej powłoki ceramicznej stwierdzono bardzo liczne mikro-i makro-pęknięcia, tworzące regularną siatkę spękań, powstałą w czasie cyklicznych oddziaływań szoków cieplnych w 400 - godzinnej próbie trwałościowej silnika spalinowego o ZS. Opisywana technologia laserowa stanowi alternatywę dla innych metod oczyszczania, głównie ze względów ekologicznych, dużej precyzji oraz szerokich możliwości automatyzacji procesu. Może być wykorzystywana również w procesach diagnostyki i weryfikacji, a także, jako technologia przygotowania warstwy powierzchniowej do innych procesów technologicznych, np. natryskiwania cieplnego, osadzania powłok kompozytowych w newralgicznych strefach tłoków.

10

Wybrane zagadnienia zastosowania LPG do zasilania tłokowych silników spalinowych

Boryna P., Januła J., Mieleń P.

Zeszyty Instytutu Pojazdów / Politechnika Warszawska

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2004

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z. 4/55

145-158

PL

W pracy dokonano oceny właściwości LPG jako paliwa silnikowego o zastosowaniach motoryzacyjnych i przedstawiono rozwiązanie konstrukcyjne układu zasilania z wtryskiem LPG w fazie ciekłej. W oparciu o przeprowadzone badania symulacyjne oraz porównawcze silnikowe stanowiskowe i trakcyjne dokonano analizy wpływu składu LPG na obciążenia cieplno-mechaniczne i stężenie składników gazów wylotowych jak również wpływu zasilania LPG na parametry efektywne pracy silnika i właściwości dynamiczne samochodu z silnikiem zasilanym LPG w fazie ciekłej.

EN

Rapid motorization development along with activities aiming at decrease of pollution and green house effect initiated searching for alternatively engine fuels. From among the former ones gas fuels and renewable biogas are mostly used due to their availability. LPG also belongs to this group . Engine equipped with combustion chamber working in Otto cycle can be used for combustion of this kind of gas fuels. This is economically reasonable since it does not require considerable engine modifications. In this paper, analysis of gas fuel properties and new system of injection of LPG in fluid phase is presented. Computer simulation was performed, engine bench tests and road tests were conducted. The investigation of influence of the composition of LPG on the value of thermal and mechanical loads and composition of exhaust gas was made. Moreover, effect of LPG supply on car dynamical properties and engine efficient parameters was analyzed.