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1

Pulse powered turbine engine concept – numerical analysis of influence of different valve timing concepts on thermodynamic performance

Tarnawski P., Ostapski W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2018

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Vol. 66, nr 3

373--382

EN

The present work is an attempt to create the concept of an engine that will combine the benefits of a pulse powered piston engine and continuously powered turbine engine. The paper focuses on the subject of pressure gain combustion (PGC). A turbine engine concept with stationary constant volume combustors, working according the Humphrey cycle, is presented. Its work has to be controlled by valve timing system. Four different valve timing concepts were analyzed. Their influence on thermodynamic performance of engine was evaluated. Different valve constructions were researched by means of 3D numerical computational fluid dynamics (CFD) simulation.

2

Tendencje rozwojowe okrętowych silników spalinowych

Kowalski J.

Przegląd Mechaniczny

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2016

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nr 12

19--24

PL

W ostatnim 10-leciu nastąpił gwałtowny rozwój konstrukcji tłokowych silników spalinowych. Był on spowodowany m.in. zaostrzeniem przepisów dotyczących ochrony środowiska, w tym emisji związków toksycznych do atmosfery. W pracy zaprezentowano nowe rozwiązania techniczne stosowane w silnikach okrętowych, prowadzące do ograniczenia emisji tlenków azotu i tlenków siarki przy jednoczesnym ograniczeniu zużycia paliwa. Prezentowana analiza ma na celu przedstawienie i ocenę dostępnych rozwiązań konstrukcyjnych oraz próbę oceny dalszych kierunków rozwoju silników stosowanych w okrętownictwie. Skupiono się przy tym na tych rozwiązaniach konstrukcyjnych, które wpływają na przebieg procesu spalania w cylindrach silnika. Przedstawione zostały również koncepcje, które jak dotychczas nie znalazły szerszego zastosowania w okrętownictwie, ale mogą stanowić obiecującą alternatywę w przyszłych rozwiązaniach konstrukcyjnych silników spalinowych.

EN

Rapid development of the construction of internal combustion engines occurs in the past 10 years. It was caused by, i.e. the growth of environmental legislation, including toxic emissions into the atmosphere. The paper presents new technical solutions, used in marine engines, leading to the reduction of emissions of nitrogen oxides and sulfur oxides while reducing fuel consumption. Mentioned analysis is to present and evaluate the available design solutions and attempt to assess further development directions of marine engines constructions. The special attention was paid on construction solutions which influence on the combustion process in the engine cylinders. Paper includes concepts that so far have not found wider application in shipbuilding also, but it may be a promising alternative for future construction solutions for combustion engines.

3

Influence of intake valve closure angle on IC engine indicated parameters

Grab-Rogaliński K., Szwaja S.

Journal of KONES

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2015

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Vol. 22, No. 3

29--35

EN

The paper presents results of modelling study of influence of an intake valve closure angle on IC engine indicated parameters. The modelled engine was Andoria S231, which was working on methane. At first, optimizations of the model were done by comparison of the indicated mean effective pressure for real engine and modelled engine. Next, modelling was done for early intake valve closure angle in comparison to original closure angle. The engine was simulated as a naturally aspirated one and for the cases such indicated; parameters as indicated efficiency, mean indicated pressure, fuel consumption were calculated. During the modelling ignition, timing and air-fuel ratio were fixed. For better comparison for two cases of early intake valve closure angle the engine was modelled as super-charged one where mean indicated pressure was fixed at the same level as for the naturally aspirated engine working with original valve timing and indicated parameters were calculated and compared with in parameters determined from this naturally aspirated engine. Because of the calculations, characteristics of indicated parameters vs. intake valve closure angle were computed. As a result of this research, both the decrease in indicated efficiency, indicated mean effective pressure were shown, temperature of fresh charge, end of compression stroke and maximum in-cylinder temperature were observed for naturally aspirated engine with early intake valve closure angle.

4

Decreasing of movable masses in valve timing using roller tappet

Warda B., Siczek K.

Journal of KONES

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2012

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Vol. 19, No. 1

473-481

EN

The method for reduction of valve timing movable masses, by the use of composite cams for camshaft, which mate with roller tappet, is presented. It has been carried out an analysis of stresses under the surface of the cam using the methodology and computer programs allowing the synthesis and analysis of the cam mechanism, and to estimate the fatigue life, as well as using the finite element method. Mating roller tappets with a light camshaft, forged from TiAl alloy, can be done if the camshaft has steel caps set under the pressure on the surfaces their cams. The problem, however, is the formation of high stress in the Bielaiev point, when a roller tappet mates with segment cam. Because of the certainty for the cap fixing, it is assumed that the depth for the Bielaiev point should not exceed half the thickness of the cap. The stress analysis shows, that exceeding of the material yield strength is controlled by the interference value between the cam and its cap and by the apex radius of the cam. Effect of contact stress is at least an order of magnitude smaller. The maximum depth of the Bielaiev point does not exceed 0.09 mm, which is about half the thickness of the proposed cap. There is a need not for too small radii between the cam and the apical cap. Optimal selection of proper geometry of the cam will be easier after a proper modification of the program used for the synthesis and analysis of the cam mechanism, such that it is possible to ask any operational surface of the cam profile.

5

Mathematical model of the hydraulic valve timing system

Mitianiec W., Bac J.

Journal of KONES

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2011

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Vol. 18, No. 2

311-321

EN

The paper presents a conception and mathematical model of the hydraulic valve timing system. It describes the complex physical phenomena that occur between system components and the hydraulic liquid. Basing on postulates and initial conditions model, one was simulated the movement of elements system resulting from the flow of pressured liquid. The model was simulated in Matlab/Simulink program for different geometrical parameters of the hydraulic system and electric control parameters in order to obtain required lift and timing of valves in YARIS SI 1.3 l engine. The paper presents structure of Simulink model and results of calculation in Simulink. One represented the influence of various parameters and dimensions system on the character of valve lift. The relationship between the diameter of the rod and the liquid significantly affects the valve time-area parameter. The feeding liquid pressure in the system and the re-steering time have the biggest influence on course of valve lift. After preliminary tests the guidelines for the hydraulic valve timing system have been developed. The determined simulation results in Simulink were used to calculate of the device work in the engine computer model created in GT-Power program. The proposed solution was compared with the cam valve timing systems. On the basis of the simulations tests show a big superiority of the hydraulic valve timing system at higher rotational speeds.

6

Tribological properties of the seat insert - valve - guide assembly for valve driven magnetoelectrically

Siczek K., Siczek K.

Journal of KONES

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2010

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Vol. 17, No. 4

439-445

EN

The researches have been carried out, where the object has been the set of two friction couples: valve stem - valve guide and valve seat - seat insert. The camless driven valve has been common for each of such cases. The analyzed valve has been driven by magnetoelectrical drive. The speciał research stand has been elaborated and its scheme has been presented in the article. It has been measured the valve lift and valve acceleration, the impact force, the friction force, temperature values for valve guide and for seat insert, sound level during impacting on the stand. The aim of researches has been to determine the dynamic parameters, the friction force between valve stem and valve guide, the impact force for valve impacting seat insert vs. frequency and valve lift. The analyzed valves have mated with seat inserts and valve guides made of cast iron, in oil absence. The valves have been made of TiAl6Zr4Sn2Mo2 alloy. The researched friction couples have operated in temperature equal 293 K. The increase of frequency has resulted in small changes for values of lift and in greater changes of acceleration, during valve impact into its seat insert. The greatest values of impact force and acceleration have been for the small, middle and high values of valve lift, either. The ratio of impact force and valve acceleration has changed in thin bands. The friction force has decreased slightly with frequency increase and has decreased with valve lift increase. The sound level has increased with the frequency increase, and has not been dependent upon valve lift.

7

The simulation researches on the wear for elements of the seat insert-valve-valve guide assembly

Siczek K., Kuchar M.

Journal of KONES

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2010

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Vol. 17, No. 4

431-438

EN

The researches have been carried out, where the object has been the elements of valve trains in the different combustion engines. Those elements have been valve, valve guide and seat insert. The analysed valves have been driven by special camshaft, with the cams of trapezoid shape. The special research stand has been elaborated and its scheme has been presented in the article. The mentioned research stand has been driven by electric motor. The rotational velocity of the camshaft has been controlled and measured. The aim of the researches has been to obtain values of wear for valve, seat insert, valve guide vs. valve lift, and rpm of camshaft. The dynamic parameters have been analyzed for the seat insert - valve - valve guide assembly, experimentally and by simulation either. During researches the values of valve lift, of valve acceleration, of temperature for seat insert and additionally sound level have been measured. The wear of valve, seat insert and valve guide has been measured, basing on their initial and post-research geometry. The results of experimental researches obtained for different materials for valve, valve guide and seat insert have been presented in the article. The simulation model of the analyzed seat insert - valve - valve guide assembly has been elaborated and presented in the article. Such model has been needed to calculate the values o f the settle velocityfor the analyzed valve. The wear of titanium valve has been a little greater than of the steel valve, the wear of cast iron seat insert mating with steel valve has been much greater than for titanium valve case. The wear of valve guides, made of bronze has been several times less than those of cast iron.

8

The researches on the tribological properties of elements of the seat insert-valve-valve guide assembly

Siczek K.

Journal of KONES

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2010

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Vol. 17, No. 4

423-430

EN

The researches have been carried out, where the object has been the elements of valve trains in the different combustion engines. Those elements have been valve, valve guide and seat insert. The analysed valves have been driven by special camshaft, with the cams of trapezoid shape. The special research stand has been elaborated and its scheme has been presented in the article. The mentioned research stand has been driven by electric motor. The rotational velocity of the camshaft has been controlled and measured. The aim of the researches has been to obtain values of wear for valve, seat insert, valve guide vs. valve lift, and rpm of camshaft. The dynamic parameters have been analyzed for the seat insert - valve - valve guide assembly, experimentally and by simulation either. During researches the values of valve lift, of valve acceleration, of temperature for seat insert and additionally sound level have been measured. The wear of valve, seat insert and valve guide has been measured, basing on their initial and post-research geometry. The results of experimental researches obtained for different materials for valve, valve guide and seat insert have been presented in the article. The simulation model of the analyzed seat insert - valve - valve guide assembly has been elaborated and presented in the article. Such model has been needed to calculate the values o f the settle velocityfor the analyzed valve. The wear of titanium valve has been a little greater than of the steel valve, the wear of cast iron seat insert mating with steel valve has been much greater than for titanium valve case. The wear of valve guides, made of bronze has been several times less than those of cast iron.

9

The analysis of operating conditions for valves actuated by camless coupled drive

Siczek K.

Silniki Spalinowe

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2009

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R. 48, nr 2

93-108

EN

The operating conditions for the pair of inlet or exhaust valves in a single engine cylinder has been analyzed. The differences for the phase angle position of cams, due to manufacturing faults, vibration and wear, result in differences in valve lifts for such a pair. The use of a single camless drive for the pair of valves cannot eliminate such differences in the valve lifts. When individual drive for each valve is used, the differences can be greater. The aim of the analysis is to determine the needed stiffness of the element connecting the pair of valves with the drive and permissible differences for geometrical and material properties of an individual drive, allowing to obtain the differences for the valve lifts smaller than those for the camshaft case. The analysis has been made using the elaborated FEM model, for two configurations of the camless drive. The paper also presents the dynamic parameters of the valves - drive assembly, stresses in such assembly and recommendations for stiffness of the element connecting the pair of valves with the drive.

PL

Analizowano pracę pary zaworów ssących lub wydechowych w pojedynczym cylindrze silnika. Zmiany położenia krzywek, wynikające z błędów wykonania, drgań i zużycia, skutkują różnicami w przebiegach wzniosów takiej pary zaworów. Zastosowanie pojedynczego bezkrzywkowego napędu dla takiej pary nie eliminuje różnic w przebiegach wzniosów tych zaworów. Przy indywidualnym napędzie każdego zaworu różnice te mogą być większe. Celem analizy jest ustalenie wymaganej sztywności elementu łączącego parę zaworów z bezkrzywkowym napędem oraz dopuszczalnych różnic parametrów geometrycznych i materiałowych indywidualnych napędów pozwalających uzyskiwać różnice w przebiegu wzniosów tych zaworów, nie większych niż dla napędu krzywkowego. Analizę wykonano w modelu MES dla dwóch konfiguracji bezkrzywkowego napędu. Zamieszczono wykresy parametrów dynamicznych układu zawory-napęd bezkrzywkowy, naprężenia w układzie i zalecenia co do sztywności elementu łączącego zawory z napędem.

10

Ocena możliwości zastosowania magnetoelektrycznego napędu zaworów w silniku pracującym w systemie 2/4 suwowym

Siczek K., Kuchar M.

Silniki Spalinowe

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2009

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R. 48, SC2

34--41

PL

Na świecie trwają prace nad stworzeniem silnika, który może pracować w cyklu 2/4 suwowym. Najbardziej zaawansowane badania prowadzone są przez firmę Ricardo. W swoim silnikach badawczych wykorzystywała ona elektrohydrauliczny napęd zaworów lub napęd krzywkowy, o specjalnej, chronionej patentem konstrukcji. W obecnym artykule dokonano oceny przydatności napędu magnetoelektrycznego do realizacji sterowania zaworami dla silnika o podobnej konstrukcji. W oparciu o założony przebieg wymiany ładunku wygenerowano wymaganą geometrię krzywek dla krzywkowego napędu zaworów i na tej podstawie, dla zadanej konfiguracji napędu magnetoelektrycznego zaproponowano algorytm generowania siły napędowej w magnetoelektrycznym napędzie. Analizę dynamiki zaworów, napędzanych według tego algorytmu, przeprowadzono w specjalnie opracowanym modelu, z wykorzystaniem MES. W artykule zamieszczono obliczone parametry dynamiczne zaworów dla różnych prędkości silnika spalinowego i wzniosów zaworów.

EN

The researches on creating of combustion engine running in 2/4 stroke system are made in many laboratories in the world. The most advanced results are obtained by Ricardo concern. In their research engines they used electrohydraulic valve actuators or camshafts of special patented construction. The evaluation of usefulness of magnetoelectric actuator for realization of valve timing in engine of similar construction has been made in the article. Basing on the assumed gas exchange course the needed geometry of cams has been generated and than, basing on it, the algorithm of force generation in magnetoelectric actuator has been proposed, for assumed magnetoelectric valve configuration. The analysis of dynamics of valves, actuated according to the algorithm, for elaborated FEM model has been made. The dynamic parameters of valves have been presented in the article, for different engine speeds and for different valve lifts.

11

A new approach in development of two-stroke engines

Mitaniec W., Buczek K.

Silniki Spalinowe

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2009

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R. 48, SC2

99--104

EN

The paper describes the work of high speed charged spark ignition overhead poppet valve twostroke engine, which enables to achieve higher total efficiency and exhaust gas emission comparable to four stroke engines. The outflow of exhaust gases in this type of engine is partially forced by pressure of inlet air. This publication presents the engine, which has to be equipped with direct fuel injection system enabling lower emission of pollutants. The work is based on theoretical consideration and engine parameters are determined on the simulation process by use of GT-Power program for different engine configurations. The obtained results included in the paper show influence of valve timing on engine work parameters such as BMEP and BSFC. The conclusion points out the possibility of applying two-stroke poppet valve engine as a power unit for transportation means with higher total efficiency as traditional engines.

PL

Artykuł zawiera opis pracy szybkoobrotowego dwusuwowego silnika o zapłonie iskrowym wyposażonego w zawory grzybkowe umieszczone w głowicy, umożliwiającego uzyskanie wysokiej sprawności ogólnej silnika oraz emisji gazów wylotowych porównywalnej z silnikiem czterosuwowym. Wypływ gazów spalinowych tego typu silnika spowodowany jest częściowo przez ciśnienie gazów w układzie dolotowym. Zaprezentowany silnik, ze względu na obniżenie emisji toksycznych gazów, musi być wyposażony we wtrysk bezpośredni. Praca została oparta na rozważaniach teoretycznych, gdzie parametry pracy silnika zostały wyznaczone w programie GT-Power dla różnych konfiguracji silnika. Otrzymane wyniki zawarte w pracy pokazują wpływ czasów otwarcia zaworów na takie wielkości jak średnie ciśnienie efektywne czy jednostkowe zużycie paliwa. Uzyskane wnioski wskazują na możliwość zastosowania tego typu dwusuwowego silnika jako jednostki napędowej środków transportu o wyższej sprawności ogólnej silnika.

12

A valved two stroke engine as a new power source

Mitianiec W., Buczek K.

Journal of KONES

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2009

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Vol. 16, No. 3

259-268

EN

The present work defines main conception of modern, efficient and ecologic two-stroke engine. It indicates the scope of necessary modifications that have to be made in typical four-stroke engine to prepare it to work in two-stroke mode. Taking into account some limitations (especially in valve train design) authors performed several analyzes in order to check the possibility of proper scavenging process and obtain main engine characteristics. The paper contains description of simulation approach and selected mathematical models that was applied in carried over analyzes. The results of foregoing simulations, which were obtain taking advantage of GT-Power software should be considered as preliminary since several parameters have to be defined during research and 3D simulations. In order to expose advantages of modern two-stroke engine a simple comparison of it and its predecessor was performed taking into consideration BSFC maps. The objects of simulation were fluid flow, scavenging and combustion. This comparison indicates that proposed two-stroke engine achieve significantly less break specific fuel consumption (up to 27 g/kWh drop). Paper presents diagram of new type two-stroke engine with poppet valves, which is probably the most feasible layout of two-stroke engine, and GT-Power model of simulated single-cylinder engine based on four-stroke single cylinder engine.

13

The analysis of dynamics for actuator - valve assembly in camless engine

Siczek K.

Journal of KONES

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2008

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Vol. 15, No. 4

501-508

EN

Nowadays camless inner combustion engines have become an interesting alternative for classic engines with valve timing included the camshafts. The operating conditions for such valve timing differ from analogous conditions for classic valve timing. Some of manufactures provide intensive research on different prototypes of camless engine, i.e. BMW, Valeo. The academic institutions have researched such camless engine either. There are different solutions for actuators of valves in camless engine. They could be electromagnetic, electrohydraulic or even electropneumatic actuators. One of the important problems in such valve timing is controlling of valve actuators. The actuators are controlled by electronic system, which use the signal of actual position of valve from i.e. hallotronic sensors to control the currents in actuator coils. It is critical to know relation between the actual position of valve and the actual position of coil for proper controlling values of current in coil. Values of the electrodynamic forces generated in the actuator are practically linearly proportional to current values in actuator coil. These forces decide of dynamic parameters of valve motion. One of the prototypes of camless engine have been investigated by K. Zbierski in Technical University of Lodz in Poland. The assembly of electromagnetic actuator and valve, used in the mentioned prototype, has been the research object, which has been analysed in this paper. The influence of modification of material for the coil form in actuator upon dynamic parameters, such as: displacement, velocity and acceleration, for elements of assembly has been analysed. The influence of such modification upon stresses and strains in the coil form has been analysed, either. The calculations have been made using the model elaborated with Finite Element Method. The obtained results have shown that influence of elasticity of assembly elements upon relative displacement, velocity and acceleration of valve and coil can be very important for control algorithm for actuator — valve assembly. The resulted stress and strain gradients and the courses of dynamic parameters have been presented in the paper.

14

Identification of service failures of cylinder valves of ship piston combustion engines

Korczewski Z.

Polish Maritime Research

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2007

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nr 2

19-26

EN

This paper presents selected diagnostic problems of charge exchange system of ship piston combustion engines. Theoretical background of wear process of cylinder valves was highlighted in the aspect of identification and sources of known and identifiable states of unserviceability. The presented results of endoscopic examinations concern failures of cylinder valves of the engines installed on Polish Navy ships.