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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.

2

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).

3

Research of engine pistons form point of view of thermal shocks

Sieminska B., Slawinski Z.

Journal of KONES

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2010

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Vol. 17, No. 1

411-420

EN

Experimental test results of thermal shocks for heavy duty pistons of combustion engines are presented in the paper. The range and the level of thermal loads were diverse and dependent from working engine conditions as well as the temperature ranges were adapted for real conditions in which pistons of the combustion engine work. temperature measurement results on crown and skirt of a piston during an engine operating under different conditions are presented in the paper. Measured temperature differences during engine operating were greatest in areas, where appeared greatest piston temperatures. Researches of thermal shocks were realized on the special testing device. The device this is automatic, controlled a computer, makes possible the realization of the cycle of research of thermal shocks in the necessary range of the temperature. Test results showed that in following cycles of thermal shocks took place stable changes ofdimensions ofthe piston too. Mainfactors effecting on the resistance of piston materials on thermal shocks are presented in the paper, at this essential parameters influent on the resistance of materials on thermal shocks are coefficients of thermal expansion and Young's modules. In particular thermal shock resistance of the different piston alloys, dependence of dimensional thermal tensions versus the undimensional heat flux, Basic parameters of the composite material AK12 +20%Al2O3 and standard, values of heat conductivity coefficient the and temperature on the composite piston surface, values of stresses due with the temperature field in piston, values strains in the composite piston due the temperature field, the example of the influence of the number of thermal shocks on the deformation of the piston sample are presented in the paper.