Wyniki wyszukiwania - BazTech

1

Analysis of the tribology processes of control valves of medium speed marine internal combustion engines

Monieta J.

Tribologia

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2017

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nr 4

55--63

EN

The article presents an analysis of phenomena of selected elements of piston internal combustion engines cooperating with the combustion chamber and issues related to tribological aspects. It shows an attempt to assess the state of the tribological nodes: the valve stem – valve guide and valve head – valve seat in random natural conditions. Passive and passive-active experiments were conducted in the conditions of the operation of sea ships. The effects of complex and changeable inputs were examined on the value of the normal and pathological wear in the operation of medium-speed engines. Images of wear and damaged items of tribological nodes were studied. Analysis was conducted of digital images of real objects and using an optical microscope and measurements of macro- and micro-geometry. An identification of basic processes of wear was taken.

PL

Artykuł prezentuje analizę zjawisk wybranych elementów tłokowych silników spalinowych współpracujących z komorą spalania oraz zagadnienia tribologiczne. Przedstawiono próbę oceny stanu węzłów tribologicznych: trzon – prowadnica i grzybek – gniazdo zaworu w losowych warunkach naturalnej eksploatacji. Prowadzono bierny i bierno-czynny eksperyment w warunkach eksploatacji statków morskich. Badano skutki złożonych i zmiennych wymuszeń na wartości normalnego i patologicznego zużycia w eksploatacji silników średnioobrotowych. Badano obrazy zużycia i uszkodzonych elementów węzłów tribologicznych. Wykonano analizy obrazów cyfrowych rzeczywistych obiektów i z zastosowaniem mikroskopu optycznego oraz pomiary makro- i mikrogeometrii. Podjęto identyfikację elementarnych procesów zużycia.

2

A model of fuel combustion process in the marine reciprocating engine work space taking into account load and wear of crankshaft-piston assembly and the theory of semi-Markov processes

Girtler J.

Polish Maritime Research

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2016

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nr 3

50--57

EN

The article analyses the operation of reciprocal internal combustion engines, with marine engines used as an example. The analysis takes into account types of energy conversion in the work spaces (cylinders) of these engines, loads of their crankshaft-piston assemblies, and types of fuel combustion which can take place in these spaces during engine operation. It is highlighted that the analysed time-dependent loads of marine internal combustion engine crankshaftpiston assemblies are random processes. It is also indicated that the wear of elements of those assemblies resulting from their load should also be considered a random process. A hypothesis is formulated which explains random nature of load and the absence of the theoretically expected detonation combustion in engines supplied with such fuels as Diesel Oil, Marine Diesel Oil, and Heavy Fuel Oil. A model is proposed for fuel combustion in an arbitrary work space of a marine Diesel engine, which has the form of a stochastic four-state process, discrete in states and continuous in time. The model is based on the theory of semi-Markov processes.

3

Identification of damages of tribological associations in crankshaft and piston systems of two-stroke internal combustion engines used as main propulsion in sea-going vessels and proposal of probabilistic description of loads as causes of these damages

Girtler J.

Polish Maritime Research

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2015

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nr 2

44--54

EN

The article discusses damages of essential tribological associations in crankshaft and piston systems of large power two-stroke engines used as main engines, which take place during transport tasks performed by those ships. Difficulties are named which make preventing those damages impossible, despite the fact that the technical state of engines of this type is identified with the aid of complex diagnostic systems making use of advanced computer technology. It is demonstrated that one of causes of the damages is the lack of research activities oriented on recognising random properties of the loads leading to those damages. A proposal is made for the loads acting at a given time ton tribological associations in crankshaft and piston systems of internal combustion engines used as main engines to be considered as random variables Qt. At the same time the loads examined within a given time interval tr ≤ t ≤ tz would be considered stochastic processes {Q(t): t ≥ 0}. Essential properties of the loads of the abovementioned tribological associations are named and explained by formulating hypotheses which need empirical verification. Interval estimation is proposed for estimating the expected value E(Qt) of the load Qt acting at time t. A relation is indicated between the mechanical load and the thermal load acting on tribological associations in the ship main engine crankshaft and piston system. A suggestion is formulated that a stochastic form of the relation between these types of load is to be searched for, rather than statistic relation, and a proposal is made to measure the intensity (strength) of the stochastic relation using the Czuprow’s convergence coefficient.

4

Badania wstępne zespołu prądotwórczego elektrowni okrętowej w aspekcie diagnozowania wybranych elementów jego struktury konstrukcyjnej

Zacharewicz M., Cwalina A.

Silniki Spalinowe

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2011

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R. 50, nr 3

PL

W referacie przedstawiono program oraz wyniki badań wstępnych, których celem jest opracowanie bezinwazyjnej metody oceny stanu technicznego wytypowanych elementów struktury konstrukcyjnej tłokowego silnika spalinowego niedoładowanego, nie wyposażonego przez producenta w zawory indykatorowe. Opracowywana metoda polega na jednoczesnych pomiarach ciśnienia spalin w kanale wylotowym oraz napięć międzyfazowych prądnicy synchronicznej współpracującej z silnikiem. Mierzone parametry energetyczne zostały zsynchronizowane z cyklem roboczym silnika za pomocą sygnału drganiowego pozyskanego z wtryskiwacza. Stwierdzono, że stan techniczny silnika ma znaczący wpływ na jakość wytwarzanej energii elektrycznej.

EN

In the paper the research problem and some results of preliminary investigations of a generating set of the ship's power plant are presented. The main purpose of the examinations was to develop a non-invasive method of evaluation technical conditions of selected structural elements of an undercharged diesel engine that was not equipped with indicator valves. The developed method is based on measurements of diesel engine exhaust gas pressure in exhaust manifold and phase-to-phase voltage of the synchronous generator driven by the engine, at the same time. Measured energetic parameters were synchronized with the cycle of the engine operation by means of a vibration signal coming from one of its injectors. It was found out that diesel engine technical condition exerts significant influence on generated electric power quality.