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Researches of influence kind of piston on some parameters of the S12-U Wola diesel engine

Jankowski A., Kołomecki J., Siemińska B.

Journal of KONES

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2012

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Vol. 19, No. 3

185-194

EN

Increased weight and greater requirements, regarding manoeuvring opportunities need extension of the power of combustion engines determining their powertrain units. In case of the family "W" engines, following developmental versions came into existence as a result of the modernization of the earlier version, among others thru the optimization of the combustion process, applying of the supercharging, as well as strengthening of the internal construction, which made it possible to carry greater thermal and mechanical loads. The subjects of the study were pistons made from composite materials of the small hysteresis of the alloy mounted on the S12-U combustion engine. In the novel construction of the piston, the outline of the overcoat was modified, the shape of the combustion chamber, the hole for the piston pin, grooves for the piston rings and shape of internal surfaces remained unchanged. A characteristic feature of the novel piston is the smaller hysteresis of the coefficient of thermal expansion composite alloy, alfa of which the pistons were made, whereas a so-called hysteresis is the difference of the coefficient alfa, which occurs during warming and piston cooling, and takes place during working of the piston in the combustion engine. The smaller hysteresis of the coefficient alfa makes the decreasing clearances between piston and cylinder possible, what has a beneficial influence on work parameters of the combustion engine, especially under conditions of partial loading of the engine. Basic parameters of the engine for the maximum torque characteristics and load characteristics are the object of the paper.

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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.

3

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.

4

High-quality silumin on pistons of combustion engines

Jankowski A., Pietrowski S., Sieminska B., Szymczak T.

Journal of KONES

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2009

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Vol. 16, No. 4

563-573

EN

In the paper the test results are presented for the AlSH2Cu5Ni5MgO.5CrO.05MoO.05WO.05VO.05 newly worked out silumin close to eutectic piston-silumin with the elevated content ofcopper and nickel to approx. 5% with relation to generally applied the AISH2 piston silumin. The novel silumin contains also Cr, Mo, In and V micro alloy additions in quantity approx. 0.05 percent for every element. Research of microstructure, HB hardness and coefficient of lineal thermal expansion a for the AlSil2Cu5Ni5MgO.5CrO.05MoO.05WO.05VO.05 silumin in the cast state, after the separation strengthening and additional short duration high-temperature heat-treatment were performed. Research of the microstructure of the AlSH2Cu5Ni5MgO.5CrO.05MoO.05WO.05VO.05 silumin showed the occurrence in it following constituent phases: alfa(Al), beta(Si), Al2Cu and AlMoCrWVMgNiSiCuFe. The separation strengthening brought about the coagulation of silicon emissions. The short duration high-temperature heat-treatment caused additional coagulation of silicon emissions and also its coalescence. Measurement of the HB hardness showed high hardness investigated alloy in the rough state, approx. 30% higher from the AlSi2 piston silumin. Measurement of the a coefficient of thermal expansion showed beneficial effects of novel alloy connected with the value decreasing of this coefficient as well so called hysteresis. Further studies on novel alloy will concentrate on alloy-additional and processes of the heat treatment.

5

Computer programs to model three dimensional structure of the MMC

Gawdzińska K., Szala J., Maliński M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 4

53-56

EN

This study presents two computer programs contributing to the spatial description of the composite alloy structure. In one program the structure of an alloy suspension composite is generated (reinforced with SiC particles) on the basis of the results of metallographic measurements, while the other program visualizes the model obtained in the pseudo-3D space. The work is part of research aimed at the description of quality parameters of metallic composites.