Wszystkie pola: exhaust valve - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Behaviour of the exhaust valve cladding face under the service conditions
Autorzy:: Kończewicz, W.
Smoleńska, H.
Powiązania:: https://bibliotekanauki.pl/articles/244130.pdf
Data publikacji:: 2009
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: exhaust valve
laser cladding
cobalt alloy
service wear
Opis:: During the ship engine operation one of the key problems is the exhaust valve durability. A special interest is in valve head face because this narrow part of the valve is responsible for tightness. Cobalt base laser cladding layer on the exhaust valve head face have been investigate under real service condition using the laboratory two-stroke diesel engine L22 for two years. During this time the engine was fuelling with both ordinary light fuel and biodiesel fuel. After removing from the valve head from the cylinder head the face surface were fully inspected optically. There were no damages and the surface was shining in the great deal however some dark "spots " on it. The samples made of the used valve head underwent microstructural investigation and hardness measurements. There were no observed substantial microstructural changes neither in the surface of the layer nor in the bulk of the clad. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type ofclad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases and with the present service experiment this method of valve head hard facing is suitable for practical applications.
Źródło:: Journal of KONES; 2009, 16, 1; 265-271
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Charge exchange control in a SI engine by early exhaust valve closing
Autorzy:: Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:: https://bibliotekanauki.pl/articles/248009.pdf
Data publikacji:: 2013
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: spark-ignition engine
variable valve actuation
early exhaust valve closing
open theoretical cycle
charge exchange process
exhaust gas recirculation (EGR)
Opis:: The paper tackles the problems connected with the charge exchange in internal combustion engines. The theoretical analysis of the charge exchange process in the SI engine has been presented. A system with independent, early exhaust valve closing has been analysed. The analysed system enables realization of an internal EGR and elimination of a throttling valve from an inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine. The open, theoretical cycle has been assumed as a model of processes proceeding in an engine. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle. Benefits resulting from application of the system with early exhaust valve closing have been assessed on the basis of the selected parameters: a fuel dose, a cycle work, a relative charge exchange work and a cycle efficiency. The best results within decrease of fuel consumption and increase of cycle efficiency are obtained for low engine load. The main parameters characterizing the process of the internal exhaust gas recirculation were also determined. These are the ratio and the multiplicity of the exhaust gas recirculation.
Źródło:: Journal of KONES; 2013, 20, 1; 387-394
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Hardness prediction of a cold rolled Nimonic 80A exhaust valve spindle
Autorzy:: Kang, S. W.
Heo, S. J.
Yoo, J. H.
Kang, J. H.
Powiązania:: https://bibliotekanauki.pl/articles/367227.pdf
Data publikacji:: 2019
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: Nimonic 80A
exhaust valve
stress-strain curve
hardness prediction
finite element method
zawór wylotowy
krzywa naprężenie-odkształcenie
metoda elementów skończonych
Opis:: Purpose: of this paper is to predict the hardness of cold rolled exhausts valve spindle fabricated of Nimonic 80A via axisymmetric finite element analysis, compression testing, and hardness inspection. Design/methodology/approach: The stress-strain relationship of Nimonic 80A was obtained via compression testing with deformation ratios of 10%, 20%, and 30%. Hardness changes caused by the strain hardening effect were measured in cut specimens in both the axial and circumferential directions following compression testing. The effective strain at the measurement position was calculated via finite element analysis. The regression equation for hardness changes caused by work hardening was derived from analysed strain and inspected hardness. The cold-rolling deformation of an exhaust valve spindle was analysed using axisymmetric finite element analysis. Findings: The stress-strain relationship calculated from compression testing was well expressed using the Holloman equation and the strain-hardness relationship by strain hardening was successfully regressed using the shifted power law model for Nimonic 80A, Nickel-Chromium based super alloy. Research limitations/implications: This research focused hardness prediction of spindle after ring rolling operation for generating beneficial compressive surface residual stresses for enhancing fatigue life. Further research to quantify compressive residual stress after rolling shall be followed to increase fatigue life. Practical implications: The cold rolling process is a typical incremental forming method and should be analysed under three-dimensional conditions. However, it takes lots of time to solve incremental forming analysis. To predict hardness distribution after rolling in the manufacturing field, FE analysis was performed under two-dimensional axisymmetric conditions based on the assumption of no friction generated by the rolling tool. The deformed shapes and hardness distribution from the inspection quality standard and two-dimensional FE analysis showed very similar results. Simplified finite element analysis method for ring rolling process for local area could be very effective method in the industrial field. Originality/value: The stress-strain relationship and the hardness and strain relationship were derived by compression test and hardness measurement for compressed specimen for Nimonic 80A, Nickel-Chromium based super alloy. And simplified finite element analysis method was suggested to predict deformed shape and hardness distribution of locally cold rolled region and achieved similar result between FE analysis result and Quality standard. Suggested method would be very effective method to engine spindle manufacture to predict hardness of different size of product.
Źródło:: Journal of Achievements in Materials and Manufacturing Engineering; 2019, 94, 1-2; 13-21
1734-8412
Pojawia się w:: Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Study on structures and properties of the laser cladding exhaust valve after service
Autorzy:: Kończewicz, W.
Krużycki, P.
Smoleńska, H.
Powiązania:: https://bibliotekanauki.pl/articles/244029.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: exhaust valve
laser cladding
cobalt alloy
service wear
Opis:: The cobalt base laser cladding layers which were built up on the exhaust valve head face of the heavy loaded marine diesel engine have been investigated. The valve head with cladded face were served successfully for 3000 hours in the engine of the Dar Młodzieży. After removing from the valve head from the cylinder head the face surface were fully inspected. The surface topography and roughness were evaluated. Microstructure on the cross section of the clad layer were analyzed using Scanning Electron Microscope (SEM) equipped with energy dispersive spectroscopy (EDS. Also microhardness of the clad layer was measured. The service conditions resulted with the formation of the scale which had different thickness and tended to cracking and spalling. The microstructure of the clad layers after service did not demonstrated serious degradation process. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type of clad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases, long time exposition in laboratory engine and in the end 3000 hours successfully service on the ship. After such experience laser cladding cobalt base layers may be recommended as a useful solutionfor both prolongs of the service life and a method of the regeneration of the slightly used valve heads is suitable for practical applications.
Źródło:: Journal of KONES; 2010, 17, 3; 211-216
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Utilising the resonance frequency of the engine vibration sensor in diagnostics of the exhaust valve leakage
Autorzy:: Komorska, I.
Powiązania:: https://bibliotekanauki.pl/articles/246940.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: combustion engine
valve defect
engine vibration
vibroacoustic model
Opis:: A vibroacoustic signal of an internal combustion engine contains several diagnostic information, which are -for the most part - not utilised since they require complex processing methods in order to separate useful data and to eliminate disturbances. The way of analysis ofsuch complex signal depends on the diagnostic aim. It is a rich source of information not only concerning the combustion process, but also various mechanical defects occurring in the driving system (valves, clutch, gearbox). Wear of elements as well as small mechanical defects cause the adaptation of the control system to new parameters. Thus, in many cases these adaptive systems can be masking mechanical defects. Burning out of exhaust valves or an improper valve clearance are examples of such defects. The method of diagnostics of leakages in a system: exhaust valve - cylinder, on the basis of measuring the vibration signal of the engine head is proposed in the paper. The results of the analysis of the engine vibration signal under conditions of a defected exhaust valve and an increased valve clearance are presented. The active diagnostic experiment was performed on the engine of Fiat Punto 1.2. During road tests the vibrations acceleration signal was recorded as well as certain auxiliary signals used for a synchronisation and identification of engine timing. The natural acceleration of vibrations in the resonance frequency range of the piezoelectric sensor was utilized. The vibration signal was pre-processed i.e. filtered, synchronously averaged and windowed. Satisfying diagnostic results of the valve defect or the improper valve clearance were obtained on the basis of the analysis of the engine vibration acceleration signal envelope. The signal measures explicitly indicating the valve condition were determined. The method, after certain modifications, can be applied for the on-line valve diagnostics.
Źródło:: Journal of KONES; 2010, 17, 2; 209-216
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Energy aspects of the SI engine load adjustment by early closing of inlet or exhaust valve
Autorzy:: Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:: https://bibliotekanauki.pl/articles/246087.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: spark-ignition engine
engine load
variable valve actuation
early valve closing
open theoretical cycle
Opis:: The theoretical analysis of the SI engine load adjustment has been presented. The load especially in SI engine is highly dependent on the process of charge exchange. This process has significant impact on the effectiveness of an engine work because it is connected with the necessity of overcoming the flow resistance, then with the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by throttling valve is especially high during part load operation. The open theoretical cycle has been assumed as a model of processes proceeding in the engine. Using fully variable inlet and exhaust valves timing the cycle can be realized e.g. according to two systems: system with early inlet valve closing (EIVC) and system with early exhaust valve closing (EEVC). Both systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle, which is theoretical cycle for the classical throttle governing of an engine load. Benefits resulting from application of the systems with independent inlet and exhaust valves control have been assessed on the basis of the selected parameters: a fuel dose, a cycle work, a charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of part load operation. Decrease of the charge exchange work leads to increase of the internal and effective works, which results in increase of the effective efficiency of the spark ignition engine. Additionally, the EEVC enables realization of the internal EGR.
Źródło:: Journal of KONES; 2016, 23, 4; 583-590
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Study of the periodic thermal contact between exhaust valve and its seat in an internal combustion engine
Autorzy:: Zemmouri, Amina
Azzouz, Salaheddine
Benchadli, Djillali
Ayad, Amar
Chaoui, Kamel
Powiązania:: https://bibliotekanauki.pl/articles/24200828.pdf
Data publikacji:: 2023
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:: seat thermal behavior
contact surface evolution
contact surface topography
thermal diffusivity
Opis:: The focus of internal combustion engine development for urban vehicles is shifting towards reducing materials by making them lighter. In order to maintain thermal and flow levels, a model was developed to study the thermal behavior of valve seats during periodic contact, which can also help improve engine performance and fuel efficiency. The model, composed of two cylindrical bars in periodic contact, takes into account the evolution and topography of the contact surface. The model's performance was evaluated through various experimental studies and showed a maximum difference of 5.05% with experimental values, in good agreement with previous literature. The results showed that heat flux increases with increasing contact frequency and thermal diffusivity affects conductive transfer. This model can be used by manufacturers to evaluate cylinder head temperature and by the automotive industry to improve heat transfer in engines.
Źródło:: Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 162911
1507-2711
Pojawia się w:: Eksploatacja i Niezawodność
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The modeling of the heat loads in the exhaust valve from and without regard of the carbon deposit
Autorzy:: Jędrusik, D.
Gustof, P.
Powiązania:: https://bibliotekanauki.pl/articles/243988.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: numerical techniques
analysis and modelling of heat loads
valve
carbon deposit
FEM
Opis:: This paper presents the modelling of the heat loads in the exhaust valve from and without regard of carbon deposit in initial phase of work of the turbocharged Diesel engine by using the two-zone combustion model, finite elements method (FES) and program Cosmos/M. In order to illustrate the problem the valve face is divided into two equal areas, then it was assumed that one of them is covered with a thin layer of carbon deposit. Modelling was conducted based on the boundary conditions III kind as a function of time, which describes the convective heat transfer coefficient and the temperature of the surrounding surfaces of valve. As a result of the calculations was compared obtained temperature distribution on the surfaces of the valve - with and without carbon deposit. The study also performed an analysis of the stress distribution that arises in the valve by the presence of the carbon deposit on the surface of the face valve. The analysis showed that the face valve heats up unevenly, more slowly on the side of the carbon deposit. Moreover small increase of the temperature causes the increase of the stress values. Maximum values of stresses do not appear in a valve face under a layer of carbon deposit but on the line distributing the surface covered with carbon deposit and without carbon deposit, near the valve face. These stresses cause the growth of microcracks in the area of the valve face, which finally give occasion to the defect of material, the damage of the valve and engine failure
Źródło:: Journal of KONES; 2010, 17, 3; 173-179
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Impact of Material Selection on Durability of Exhaust Valve Faces of a Ship Engine – A Case Study
Autorzy:: Smoleńska, Hanna
Kończewicz, Włodzimierz
Bazychowska, Sylwia
Powiązania:: https://bibliotekanauki.pl/articles/102904.pdf
Data publikacji:: 2020
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: cobalt alloy
laser cladding
exhaust valve
stop kobaltu
napawanie laserowe
zawór wydechowy
Opis:: Two alloys were used in order to extend the service life of marine engine exhaust valve head. Layers of cobalt base alloys were made of the powders with chemical composition as follow: the layer marked L12; C-1.55%; Si-1.21%; Cr-29.7%; W-9%; Ni-2%; Mo<0.01%; Fe-1.7%; Co-54.83% and the layer marked N; C-1.45%; Co-38.9%; Cr24.13%; Ni-10.43%; W-8.75%; Fe-7.64%; Mo-7.56%; Si-2.59%. Base metal was valve steel after heat treatment. It was consisted of: C-0,374%; Cr-9,34%; Mn-0.402%; Ni-0.344%; Si-2.46%; Mo-0.822%; P-0.0162%; S-0.001%. Layers on the valve faces were produced by laser cladding using the HPDL ROFIN DL020 laser. Grinding treatment is a very popular form of regeneration of seat and valve plug adhesions. Properly performed grinding operation ensures dimensional and shape accuracy of the surface from 7 to 5 accuracy class and surface roughness Ra not less than 0.16 μm, depending on the object and method of grinding. The 75H and 150S types are a significantly simplified form of valve plug face grinders. Finishing treatment was carried out with a Chris-Marine AB75H sander on a sanding stand equipped with a compressed air system - the stand was designed by the author. The sander has been set up to the surface of the valve stem so that the grinding angle of the valve faces is 30°+10°. A flat grinding wheel T1CRA54–K was used for machining. The plunge feed was 0.01 mm/rev. The thickness of the welded layer after grinding was 1.2 mm. Both valves were installed in the ship’s engine and were used in real life. After 2000 hours of operation, the valve marked N was damaged. The valve marked L12 showed no damage and was in operation for the next 1000 hours.
Źródło:: Advances in Science and Technology. Research Journal; 2020, 14, 3; 165-174
2299-8624
Pojawia się w:: Advances in Science and Technology. Research Journal
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Difference spectrum as a measure of the state of wear of the exhaust valve
Widmo różnicowe jako miara stanu zużycia zaworu wylotowego
Autorzy:: Górnicka, D.
Powiązania:: https://bibliotekanauki.pl/articles/328575.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:: combustion engine
exhaust valve
damage
failure diagnosis
vibroacoustic symptom
silnik spalinowy
zawór wylotowy
uszkodzenie
diagnostyka
symptom wibroakustyczny
Opis:: The article presents an algorithm of diagnosing damages to the exhaust valve of the combustion engine. The process of obtaining a symptom as a difference spectrum takes into account time selection, which allows to reduce significantly the calculations necessary to obtain a measure of malfunction. As a result, we obtain a simple measure not requiring special conditions of object work and insensitive to simultaneously occurring valve clearance which is inappropriately set. Thus, we obtain a measure easy to use in diagnostics in real time.
W artykule przedstawiono algorytm diagnozowania uszkodzeń zaworu wylotowego silnika spalinowego. Proces pozyskania symptomu w postaci widma różnicowego uwzględnia selekcję czasową, co pozwala znacznie ograniczyć obliczenia niezbędne do otrzymania miary niesprawności. W efekcie otrzymujemy miarę prostą, niewrażliwą na równolegle występujący nieprawidłowo ustawiony luz zaworowy i nie wymagającą specjalnych warunków pracy obiektu. Tym samym otrzymujemy miarę łatwą do wykorzystania w diagnostyce w czasie rzeczywistym.
Źródło:: Diagnostyka; 2016, 17, 4; 59-64
1641-6414
2449-5220
Pojawia się w:: Diagnostyka
Dostawca treści:: Biblioteka Nauki

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