Wyniki wyszukiwania - Biblioteka Nauki

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Diagnostyka techniczna uszkodzeń czterosuwowego morskiego silnika Sulzer 3AL 25/30 z wykorzystaniem zmian stosunku absolutnego ciśnienia sprężania do absolutnego ciśnienia doładowania

100%

Drewing S.

Zeszyty Naukowe Akademii Morskiej w Gdyni

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2018

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tom nr 105

32--40

PL

W artykule przedstawiono wyniki badań wpływu wprowadzanych uszkodzeń (układu wtryskowego umiejscowionego w środkowym cylindrze silnika (cylindrze nr 2) lub w obrębie układu zasilania powietrzem silnika dla wszystkich cylindrów) czterosuwowego morskiego silnika Sulzer 3AL 25/30 na zmianę stosunku absolutnego ciśnienia sprężania do absolutnego ciśnienia doładowania, nazywanego współczynnikiem βp.

EN

This paper presents research results regarding influence of damages (injection system located in the central engine cylinder (cylinder no. 2) or within the engine air supply system for all cylinders) of four-stroke marine engine Sulzer 3AL 25/30 on ratio changes in the absolute pressure of compression to absolute pressure of boost (denominated βp ratio).

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Decomposition of harmonic wavelets of torsional vibrations as basis for evaluation of combustion in compression-ignition engines

63%

Dereszewski M. , Drewing S.

Journal of KONES

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2018

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tom Vol. 25, No. 3

129--135

EN

The aim of analysis presented in the article is results of measurements of torsional deflections of a crankshaft of three-cylinder internal combustion diesel engine. The wavelets of the run of torsional twists were processed by decomposition to harmonics using FFT. In order to exactly recognize all dynamic aspects of gas forces acting during working stroke, decomposition was done in two ways: first one relaying on records encompassing one working cycle (two revolutions), the second one based at separated periods encompassing angular an interval from TDC (Top Dead Centre) of one cylinder to TDC of subsequent in firing order. For three-cylinder engine, width of the interval is 240 degrees of crank angle. In order to obtain reliable results, torsional deflection signals acquisitions were recorded numerous times including changes of outer conditions (temperature, atmospheric pressure) and different values of the engine loads. The main goal of conducted experiments was looking for an answer of a question if exist any differences between frequency spectrums of harmonics of run of full cycle ( two revolutions) and the same cycle divided by three separate intervals. Analysis was conducted in order to state any possibility of diagnostic signals acquisition caused by abnormalities of combustion process. Results were presented in form of comparison of frequency spectra taken from full cycle and divided intervals.

3

Wpływ wzrostu dawki paliwa na zmiany amplitud składowych harmonicznych drgań skrętnych wału zespołu spalinowo-elektrycznego

63%

Drewing S. , Dereszewski M.

Zeszyty Naukowe Akademii Morskiej w Gdyni

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2018

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tom nr 108

34--42

PL

Artykuł przedstawia wyniki badań wpływu zmian dawki paliwa na składowe harmoniczne drgań skrętnych wału zespołu spalinowo-elektrycznego, ze szczególnym uwzględnieniem składowej harmonicznej odzwierciedlającej wtrysk paliwa. W badaniach wykorzystano metodę pomiaru drgań skrętnych wału za pomocą zmian chwilowych prędkości kątowych.

EN

The article presents the results of research on the impact of changes in the fuel dose on the harmonic components of torsional vibrations of the shaft of the combustion-electric unit, with particular emphasis on the harmonic component responsible for fuel injection. In the tests, the method of measuring torsional vibrations of the shaft was used by means of changes of instantaneous angular velocities.

4

Diagnostic of malfunction of four stroke marine engine using harmonic components of combustion pressure waveforms

63%

Drewing S. , Dereszewski M.

Journal of KONES

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2018

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tom Vol. 25, No. 2

97--103

EN

The paper presents results of experimental measurements and analysis of combustion pressure and fuel pressure in high-pressure line before fuel valve. The aim of conducted experiments was detection of failures of high-pressure fuel system. Both pressure signals were recorded simultaneously and subsequently processed using FFT decomposition of obtained wavelets. The idea of comparison of both fuel and gas pressures came after observations of occurrence changes of wavelets form of fuel high pressure, probably caused by malfunction of injector's sprayer. The engine from test bed is very well armoured with sensors, what enable observations of fuel and combustion pressure in real time. Unfortunately, such equipment is very unlike in real objects, what created un idea to find out whether run of combustion pressure wavelet reflects fuel pressure deviations and whether is possible to detect such kind of deviations in way of decomposition of indicated pressure wavelet. Experiment was carried out in laboratory of Gdynia Maritime University, using medium speed diesel engine. Simulation of malfunctions of fuel valve was obtained by installation of specially prepared spraying nozzles. All measurements were carried out at reference load of 75% of MCR (Maximum Continuous Rating). In order to get reliable results and avoid errors due to omitting outer atmospheric conditions, registrations were repeated several times, in days characterized by different temperature and atmospheric pressure.

5

Statistical methods in the analysis of strength parameters of epoxy-glass composites modified with rubber recyclate

51%

Drewing S. , Abramczyk N. , Żuk D. , Dyl T.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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tom Vol. 117, nr 2

71--78

EN

Purpose: The article presents a statistical analysis of strength parameters of newly developed epoxy-glass composite materials modified with the addition of rubber recyclate. Design/methodology/approach: Three variants of materials with a percentage of recyclate content in the composite matrix of 3%, 5%, 7% and a reference variant without the addition of recyclate were used for the study. The samples were subjected to an impact test on a ZWICK RKP 450IR-GE impact hammer. Resilience measurement values were subjected to statistical analyses at the significance level α = 95%, such as: testing the normality of distributions with the Shapiro-Wilk test, testing differences between pairs with the Student's t-test for dependent groups, and testing ANOVA differences for independent groups. Findings: The Shapiro-Wilk test confirmed that the resilience variables for all tested samples were in normal distributions; therefore the highest power parametric tests were used to test the differences. Using the Student's t-test, it was confirmed that between pairs of variables in configurations: standard sample with the modified sample, there were significant statistical differences in the distribution of resilience values for all samples. ANOVA confirmed significant changes in impact strength in 10 comparison variants. Research limitations/implications: The obtained test results showed that in 9 compared cases, there were significant statistical differences, and in one case, there were no significant differences. Practical implications: The performed statistical analyses confirmed their significant usefulness in the process of qualification of strength parameters for materials with high anisotropy, such as composites. Originality/value: The manufactured products are innovative in terms of the method of using the addition of rubber recyclate as a filler for epoxy-glass composites. The use of static methods for their study also has practical value. It optimizes the analysis methods of the results of measurements of strength parameters of new composite materials.