Wyniki wyszukiwania - BazTech

1

Simulation research of the hydraulic drive for valves of internal combustion engine

Szydłowski T., Smoczyński M.

Journal of KONES

|

2013

|

Vol. 20, No. 2

385--391

EN

This paper describes simulation research of single-acting hydraulic drive for valves of internal combustion engines. The proposed drive was composed of commercial servovalve and typical hydraulic single-acting actuator. Research was performed for the prepared and verified model of this drive. In the paper mainly analysed was the impact of control signals on course of valve lift and its characteristic parameters like: delay of start of valve movement in opposition to the start of the control signal, the time of opening and closing of the valve, the valve lifting time, the course of valve lift, fill factor of the area under the valve lift curve and velocity of the valve subsidence. Special attention was given to the closing movement of the valve. Drive control was limited to step control signal. In the final phase of closing the valve, the control method had to slow down and stop the valve, but without a significant influence on the valve closing phase. During research the fill factor of the area under the valve lift curve was calculated and compared with values obtained for the classic drive with cam. A number of simulations allowed to determine the optimal control signal for the course with deceleration of the valve. Based on simulation studies it was found that comparable fill factors of the area under the valve lift curve for cam drive and analyzed electrohydraulic drive were obtained up to over 4000 rpm speed. Above this speed the factor was significantly smaller for hydraulic drive. For low engine speeds the values of factor were acceptable and amounted to about 0.7. Unfortunately for the valve opening times for engine speed 6000 rpm, tested drive did not provide the full opening of the valve and the fill factor of the area under the valve lift curve was unsatisfactory. In this research, the frequency characteristics of the servovalve published by their manufacturers were used. It demonstrated that because of the delay and response speed of the valve is necessary to use units generating a control signal ahead in relation to the desired moment of opening the valve.

2

Experimental research of properties of hydraulic drive for valves of internal combustion engines

Szydłowski T., Smoczyński M.

Journal of KONES

|

2013

|

Vol. 20, No. 1

351--358

EN

This paper describes a research stand and results of experimental research of single-acting hydraulic drive for valves of internal combustion engines. The research stand of the hydraulic valve drive was consisted of: typical valve drive for high-speed internal combustion engine, commercial hydraulic actuator, commercial hydraulic accumulator and electrically controlled hydraulic distributor, which controlled the flow of oil supply to the hydraulic actuator. Rexroth commercial servovalve was used as hydraulic distributor for this valve drive. Components of hydraulic valve drive were mounted to specially designed research sleeve. On this sleeve complete drive, which consisted of a hydraulic cylinder and servovalve, was mounted. Drive control was performed in an open loop with a use of rectangular control signal. Displacement of the valve was measured by an optical displacement sensor. Tests were performed for constant lift of the valve, supply pressure set in the range of 6 to 10 MPa and at fixed temperature of the working medium and different initial deflections of valve spring. The behaviour of the drive was researched for bipolar and a rectangular control signals. Such range of measurements was to determine inter alia: the impact of the supply pressure and the control signals values on the drive work. Obtained results were used to verify the simulation model in a wide range of variation of the characteristic parameters of the electro-hydraulic actuator. The results of experimental measurements like valve movement and pressures in the drive were shown and analysed in this paper. With a reference to the valve movement, a detailed calculations of the valve kinematics were performed. Special attention was given to the opening and closing velocities of the valve, depending on the servo control signal. Subsidence valve velocity during its return movement was calculated. This subsidence valve velocity is an important parameter in terms of the applicability of this drive for the internal combustion engines. Valve opening time delay in opposition to the current control signal was also specified and discussed. Obtained results allowed to conclude that the proposed drive provides acceptable kinematic parameters for high-speed engines at supply pressures of at least 8 to 10 MPa. During the measurements acceptable valve subsidence speeds were obtained. It was found that there is a possibility of adjustment of this parameter by setting the slider servovalve negative overlap. Results became the basis of development of the model of this type of the drive. Further simulation studies will allow to evaluate the applicability of such valve drive for internal combustion engines. Further simulation studies allow to compare the proposed solution with known literature hydraulic valve drives.

3

Wpływ klasy czystości cieczy na zjawisko erozji krawędzi sterujących suwaka serwozaworu

Minorowicz B., Stefański F.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

|

2012

|

nr 3

28-31

PL

Autorzy artykułu postanowili przedstawić zagadnienie czystości cieczy hydraulicznych oraz jej wpływ na niezawodną pracę serwozaworów. Zanieczyszczenia zostały sklasyfikowane względem źródeł ich pochodzenia oraz wywoływanych skutków. Spośród występujących w serwozaworach procesów zużyciowych, teoretycznej analizie poddano zużycie erozyjne. Dla serwozaworu Vickers SM 4-20-10 wyznaczono maksymalne prędkości przepływu i na tej podstawie określono energię uderzających w krawędzie cząsteczek.

EN

Authors decided to present a hydraulic fluids contamination issue and its influence on the reliable operation of the servovalves. Contaminations were classified relative to their sources, and its effects. Among wear processes occurring in the servovalves, theoretical analysis of erosive wear was performed. For Vickers SM 4-20-10 servovalve set the maximum flow velocity and on this basis the energy of particles hilling the edges.

4

Experimental verification of the model of electrohydraulic drive for internal combustion engine valves

Szydłowski T.

Journal of KONES

|

2009

|

Vol. 16, No. 3

401-408

EN

The paper presents experimental electrohydraulic valve drive for internal combustion engine. The design is asingle-acting hydraulic actuator with spring return controlled by servovalve. Such solution shouldgive free control of valve lift, valve open and valve close time. In the article the principles of the operation of the drive are described. The paper focuses on exploring the dynamic of experimental electrohydraulic engine valve actuation system working in open-loop. For investigations the mathematical and simulation models were elaborated. The values of unknown coefficients of the models were intercepted on two test stands. First of them served to servovalve research. Second was built on the basis of the prototype drive and let on the research of the dynamics of the all drive. Chosen results of these investigations are placed in the article. The drive was explored for different oil supply pressures, control signals and spring mounting lifts. Experimental dates let to verified dynamic mathematical model. Comparisons of valve lift proceedings obtained from experiments and simulations are presented in the article. Verified model let to execute the analysis of the features of such drive and point necessary modifications for the correct realization of the process of the gas exchange in internal combustion engine.

5

Model of hydraulic double-acting drive for valves of internal combustion engine

Szydłowski T., Smoczyński M.

Journal of KONES

|

2009

|

Vol. 16, No. 1

487-494

EN

The article presents the idea and the model of electrohydraulic double-acting valve drive for internal combustion engine. In this solution to control the position of the engine valve used Rexroth's servovalve and the double-acting actuator. This drive should give free control of valve lift, valve open andvalve close time. In the article the principles of the operation and the mathematical model of the drive are described. Submitted model gives bases to the initial value definition of the main parameters of the hydraulic drive. It lets execute the analysis of the features of such drive and point necessary modifications for the correct realization of the process of the gas exchange in internal combustion engine. The first results from the simulation showed that proposed solution allows obtaining desirable run of lift of valve in the wide range of engine speed. Comparisons of valve lift proceedings driven hydraulically and mechanically by the use of harmonic cam, for two engine speeds, obtained from simulations are presented in the article. These comparisons show that at greatest engine speeds it is indispensable the use of pressures of the working liquid exceeding 10 MPa to obtain nearing results to the classical mechanical timing gear. Preliminary simulation test results indicate that it may ensure desired run of lift of valve in the wide range of engine speed

6

Modelling of the electrohydraulic full active vehicle suspension

Konieczny J.

Engineering Transactions

|

2008

|

Vol. 56, iss. 3

247-268

EN

The study investigates various models of vehicle suspensions. A quarter-vehicle full active suspension is chosen for further analysis. A mathematical model, governed by nonlinear differential equations, is proposed that takes into account dynamic properties of an electrohydraulic actuator. The mathematical model being implemented, it was expressed in terms of the state variables. In part two, the physical model was implemented and parametric identification procedure was applied. Phenomenological model simulation data are compared with results of experimental testing of a full, active vehicle suspension. The final section is focused on static and dynamic properties of an openloop system (without a controller) determined on the basis of obtained models.

7

Badanie elektropneumatycznego układu wibroizolacji z adaptacyjnym układem stabilizacji wibroizolacyjnej masy

Korzeniowski R.

Czasopismo Techniczne. Mechanika

|

2008

|

R. 105, z. 1-M

137-149

PL

W artykule opisano układ dwukomorowej sprężyny pneumatycznej z serworozdzielaczem elektropneumatycznym i układem sterowania realizującym adaptacyjny algorytm stabilizacji wibroizolowanej masy. Projekt zrealizowano w Laboratorium Układów i Struktur Dynamicznych AGH. Połączenie tradycyjnych technik wibroizolacji z nowoczesnym układem sterowania przepływem gazu do i z komór sprężyny pneumatycznej korzystnie wpłynęło na właściwości użytkowe badanego układu wibroizolacji. Układ posiada m.in. zdolność adaptacji do zmieniających się warunków obciążenia. Zastosowany algorytm sterowania nie wpływa na kształt charakterystyki przenoszenia drgań dla częstotliwości powyżej 3 Hz. Dla częstotliwości niższych obserwowane jest wyraźne spłaszczenie szczytu rezonansowego. Przeprowadzone badania symulacyjne i laboratoryjne potwierdzają możliwość zastosowania opracowanego rozwiązania w konstrukcji nowoczesnych zawieszeń pojazdów osobowych, zawieszeń kabin pojazdów ciężarowych, jak również siedzisk maszyn roboczych.

EN

In the paper has been described double chamber air spring with electropneumatic servovalve and adaptive control system witch realize sprung mass stabilisation. Project has been realized in Laboratory of Dynamic Systems and Structures of AGH-University of Science and Technology. Connection between traditional technique and modern system controlling air flow to and out of air spring chamber has beneficial influence on the vibroisolation system exploitation parameters. Among others system has additional ability of adaptation to load changes. Developed algorithm do not influence into shape of transmissibility characteristic for frequencies grater than 3 Hz. Below that frequency significant resonant pick suppression has been observed. Mathematical modelling and laboratory tests have been carried out and they proof that designed system can be used in of modern suspension of cars, track cabs and seats of heavy duty machines construction as well.

8

Modelowanie serwozaworu z piezoelementem belkowym w stopniu sterującym i z elektrycznym sprzężeniem zwrotnym

Sędziak D., Pelic M.

Archiwum Technologii Maszyn i Automatyzacji

|

2008

|

Vol. 28, nr 4

79-88

PL

Obecnie jedną z obiecujących koncepcji jest wykorzystanie piezoelementów, takich jak stosy piezoelektryczne i piezoelementy belkowe, jako napędów. W artykule przedstawiono budowę serwozaworu elektrohydraulicznego z piezoelementem belkowym w stopniu sterującym. Zaproponowano model zaworu z takim stopniem sterującym oraz przedstawiono porównanie wyników badań symulacyjnych z badaniami doświadczalnymi.

EN

One of today promising idea is using piezoelements like piezo stack or piezo benders as control elements. In the paper piezo control stage concept and experimental construction were described and shown. Matlab Simulink model of piezo-actuated servovalve was shown. Results of model simulation and servovalve experimental researches were compared and discussed. As shown simulation results of prepared model well correspond to experimental results. Piezobender can be used with good success as control element in modern servovalves.

9

Poprawa histerezy w serwozaworze z piezoelementem belkowym w stopniu sterującym

Sędziak D.

Archiwum Technologii Maszyn i Automatyzacji

|

2007

|

Vol. 27, nr 2

137-142

PL

W artykule przedstawiono wyniki badań doświadczalnych nad zastosowaniem piezoelektrycznego elementu belkowego jako elementu sterującego pracą zaworu. Piezoelement umieszczony jest w stopniu sterującym i pracuje w zaworze jako przysłona dysz. Porównano charakterystyki piezoelenientu zasilanego za pomocą wzmacniacza napięciowego i wzmacniacza ładunku oraz odpowiedzi serwonapędu dla tych przypadków sterowania elementu piezo.

EN

In the paper electrohydraulic servovalve controlled by single piezobender element was presented and investigated. The control stage design concept and experimental construction was described and shown. Results of hysteresis experimental investigation for voltage and charge control method for piezo bender was shown and discussed. Some comparison of experimental results of response hysteresis of servodrive with piezovalve was presented. As shown, charge control for piezoelement can reduce response hysteresis of piezo bender and servodrive. Experimental results shown that piezo-bender can be used with good success as control clement for servo valves.

10

Basic investigations of electrohydraulic servovalve with piezo-bender element

Sędziak D.

Archiwum Technologii Maszyn i Automatyzacji

|

2006

|

Vol. 26, nr 2

185-190

EN

One of promising today idea is usage of piezoelements like piezo stack or piezo-benders as control elements for hydraulic and pneumatic valves. In the paper basic research of electrohydrau-lic servovalve with piezo-bender was presented and investigated. The main design concept of control stage was shown. Results of investigations from first stage of research were presented and discussed.

PL

W publikacji przedstawiono koncepcję stopnia sterującego do serwozaworu elektrohydraulicznego, w którym przysłonę dysz stanowi piezoelektryczny element belkowy. Przedstawiono konstrukcję zmodyfikowanego stopnia sterującego do wybranego zaworu. Omówiono wstępne wyniki badań doświadczalnych serwozaworu z takim stopniem.

11

Model serwozaworu elektrohydraulicznego z elektrycznym sprzężeniem zwrotnym

Milecki A.

Archiwum Technologii Maszyn i Automatyzacji

|

2000

|

Vol. 20, Nr 2

105-112

PL

W artykule przedstawiono zależności opisujące dynamikę poszczególnych elementów serwo-zaworów z elektrycznym sprzężeniem zwrotnym oraz określono zakresy zmienności występujących w nich współczynników. Scharakteryzowano podstawowe nieliniowości i wprowadzono je do modelu symulacyjnego. Przedstawiono schemat blokowy modelu komputerowego serwozawo-ru zbudowany z wykorzystaniem pakietu Matlab-Simulink. Uzyskane w wyniku symulacji krzywe przebiegu odpowiedzi skokowych porównano z krzywymi zamieszczonymi w katalogu.

EN

In the paper the servovalve with electrical feedback linkage is described. The equation and the gain coefficients values characterised the dynamic properties of such servovalve are given. The main nonlinearities are described and included into a model. The simulation model made in Matlab-Simulink program is presented. Step responses of the model made by simulations are shown and compared with step responses given in catalogues.