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Energy analysis of propulsion shaft fatigue process in rotating mechanical system Part I Testing significance of influence of shaft material fatigue excitation parameters

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Korczewski Z. , Marszałkowski K.

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tom S 1

211--217

EN

The article discusses the problem of mathematical modelling of energy conversion processes in a rotating mechanical system for the purpose of identifying fatigue states of propulsion shafts in this system. A simplified physical model of the analysed system, constructed in an appropriate scale, has made the basis for the experimental research. The research programme took into consideration mechanical fatigue excitation of the model propulsion shaft to find the correlation between the dynamic system load generated by a bending moment and the energy state of a specified shaft segment. A physical model of the analysed process was proposed, for which the plan of static randomised block experiment was worked out. The recorded experimental results were used for statistical analysis of the significance of influence of the quantities exciting the propeller shaft fatigue process and the adequacy of the developed mathematical model describing shaft’s durability. The analysis made use of the F-Snedecor test. The article describes the general concept of the research, the constructed laboratory test rig, and the methodology of statistical inference concerning the significance of influence of input (exciting) parameters of the physical model on the recorded output parameters. The results of the performed statistical tests confirm the absence of the significance of influence of the rotational speed of the propulsion shaft on the selected types of rotating operation of the mechanical system. As a consequence, only one exciting parameter, which is the loading mass, is going to be taken into account in the functional description of fatigue life of the propulsion shaft.

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The oil film parameters of the wankel engine apex seal in aspects of durability of mating elements

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Iskra A. , Babiak M. , Kałużny J. , Marszałkowski K.

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tom Vol. 17, No. 4

199-206

EN

The Wankel engine is one of only few alternatives to the reciprocating engines. The advantages such as good value of maximum engine power to its mass ratio are still present and can have great sense in selected fields of application, for example General Aviation. Nevertheless the disadvantages of the Wankel engine design have never lost its importance and still pose an obstacle to wider use of the Wankel engine. One of the main drawbacks is the rotor sealing system design, especially the apex seal where single siat has to fulfil a purpose of conventional engine piston rings pack. Moreover the unfavourable changes of the apex seal angle of attack causes that optimal shape of the apex seal sliding surface, in aspects of the oil film parameters, can not be achieved. These results in worsening of apex seal elements mating conditions, reducing its effectiveness and durability. In the paper authors present results of simulation researches where oil film parameters, for example oil film thickness, which determines apex seal durability, were obtained for different engine operating conditions and various shapes of apex seal sliding surface geometry. The results indicate possible directions during apex seal designing process which should provide oil film continuity in whole rotor angle position range and for wide engine operation conditions range.

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Innowacyjna konstrukcja utleniającego reaktora katalitycznego uwzględniająca udział węglowodorów w spalinach

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Iskra A. , Kałużny J. , Babiak M. , Marszałkowski K.

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tom R. 53 nr 2 (189)

55-61

PL

Obserwowany wzrost świadomości ekologicznej leży u podstaw inicjatyw mających na celu prawne zagwarantowanie ograniczenia uciążliwości dla środowiska wszelkich pojazdów z silnikami spalinowymi. Zaostrzenie norm emisji spalin wymusza poszukiwanie nowych rozwiązań technicznych, szczególnie w zakresie układów oczyszczania spalin. W artykule przedstawiono koncepcję utleniającego reaktora katalitycznego z użyciem nanomateriałów. Naniesienie nanorurek węglowych na standardowy nośnik ceramiczny umożliwia zwiększenie powierzchni kontaktu warstwy katalitycznej ze spalinami przy ograniczeniu ilości kosztownego metalu szlachetnego zastosowanego do produkcji reaktora. Przedstawione w artykule wyniki badań emisji spalin przeprowadzonych na nowoczesnym silniku pojazdu użytkowego o zapłonie samoczynnym, z zastosowaniem opisanego innowacyjnego reaktora katalitycznego, potwierdzają możliwość uzyskania wymienionych wyżej, teoretycznie przewidzianych korzyści.

EN

The rise in ecological awareness underlines the initiatives which aim at providing legal guarantee for limitation of negative effect of all internal combustion engine vehicles on the natural environment. More restrictive emissions standards require a search for new technological solutions and designs especially in the field of exhaust gas purifying systems. The paper presents a concept of new oxidizing catalytic converter based on nanomaterials. The carbon nanotubes coating of the standard ceramic carrier allows increasing the contact area of exhaust gas with catalytic layer while reduction of the noble metals used to build a reactor. The results of experimental investigations, presented in the paper, which were carried out on modern vehicle CI engine with the innovative catalytic converter confirm the possibility of obtaining the theoretical benefits mentioned above.