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EN
Vibration energy harvesting systems are using real ambient sources of vibration excitation. In our paper, we study the dynamical voltage response of the piezoelectric vibrational energy harvesting system (PVEHs) with a mechanical resonator possessing an amplitude limiter. The PVEHs consist of the cantilever beam with a piezoelectric patch. The proposed system was subjected to the inertial excitation from the engine suspension. Impacts of the beam resonator are useful to increase of system’s frequency transition band. The suitable simulations of the resonator and piezoelectric transducer are performed by using measured signal from the engine suspension. Voltage outputs of linear (without amplitude limiter) and nonlinear harvesters were compared indicating better efficiency of the nonlinear design.
EN
Despite the fact that more than a hundred years have passed since the first design of the compression ignition (CI) engine appeared, its optimal design has not yet been achieved. It is still the subject of constant modernisation in order to meet the new expectations of users in terms of its dynamics, economy, and, in recent months, also ecology. The most effective fulfillment of these requirements is achieved through new solutions of the fuel supply system and electronic control of injection and combustion processes. The publication includes the test results obtained on the basis of two engines. One of them is the single-cylinder CI engine AVL5402, and the other one – a threecylinder CI engine AD3.152. The first one is equipped with the Common Rail fuel supply system, electronically controlled with the selenoid injector. The second engine has a CAV distributor fuel injection pump and traditional, mechanical controlled injectors. The paper demonstrates how these two different structural systems for supplying and controlling engine parameters affect the selected indicators of the injection and combustion process. The influence of diesel fuel (DF) and rapeseed oil (RO) feeding the engine in both different injection and control systems on the unrepeatibility of the injection pressure on the maximum combustion pressures in the engine cylinder and, consequently, non-uniformity of the crankshaft rotational movement of the engine were also pointed out. The continuation of the research in this area seems to be expedient. They can be supplemented with statistical models of these phenomena. The results obtained in this way could be helpful in optimising the design of power supply systems and engine combustion chambers.
EN
The paper presents the methodology for designing the injection shaft drive for diesel engines with 2,3,4,6 and 8 cylinders as well as power from 2.5 to 52 kW per cylinder using the FEM method and experimental research. The pump is the original solution of the authors. The shaft is a basic part of the pump with a complex structure. In order to assess the state of stress in the shaft, the FEM analytical method was used and experimental tests were carried out, subjecting the shaft to torsional moment resulting from the transmitted power. Experimental studies confirmed the results of numerical calculations and the correctness of the adopted solution. The destructive tests were carried out to assess the maximum load capacity of the shaft, loading it with an increasing torque until visible plastic deformations occurred. This condition appeared at twice the moment (Ms = 602 Nm) in relation to the maximum predicted moment in operation (extreme operating conditions of the pump shaft). The theoretical studies confirmed very significant stress concentration (αk coefficient at the level of 2.63 or even 4.7), which may be the cause of fatigue cracks. It also determines the strength of the shaft and its torsional stiffness, which influences the proper functioning of the pump and ensures adequate fuel injection phases.
EN
In recent years, the opposed-piston engines have become increasingly popular in the automotive and aerospace industries. Therefore, it is necessary to conduct the research on this type of drive. The paper presents the simulation research of a two-stroke opposed-piston diesel engine designed for propulsion of light aircrafts. The influence of the change of the compression ratio on the selected engine performance was investigated (indicated mean effective pressure, peak firing temperature and pressure, specific fuel consumption, power consumed by the compressor). The AVL BOOST software was used to perform the simulation tests. A zero-dimensional engine model equipped with a mechanical compressor was developed. On the basis of the created model, a series of calculations was performed for the assumed values of the compression ratio for four engine operating points: take-off power, maximum continuous power and cruising power at two different altitudes. The obtained results were subjected to a comparative analysis and the most important conclusions connected with the influence of the change in the compression ratio on the achieved performance were presented.
EN
A combustion engine turbocharger works in most difficult conditions due to high temperatures of the fuels it is driven by, vibrations and high rotational speeds of its shaft up to 200 thousand rpm. In addition, under these conditions, there are difficulties with lubrication of the blade axes. Thus, the combustion engine turbocharger is exposed to the damages occurring during the engine operation process. The frequency of damages was determined on the basis of tests for a selected group of vehicles. The object of detailed author’s own research was the Audi 3.0 V6 TDI engine of the Audi A6 C6 car which cooperated with a Borg Warner turbocharger with a variable angle of turbine steering wheel blades. These positioners are also exposed to adverse conditions: mainly vibrations and high temperatures. They are subjected to frequent damages, which often affect the engine control parameters. An analysis of the positioner element damage as well as a group of testers to assess their technical condition was made. The evaluated testers were allowed only to determine the efficiency of the turbocharger, but without indicating its technical condition or its positioner separately. Consequently, the author’s own research methodology and the construction of a new tester for the electromechanical turbocharger adjuster was developed. The necessary tests for the vehicle mileage up to 350,000 km were carried out. The self-designed tester can also estimate the degree of electromechanical wear of the positioner in the engine supercharging system as well as the resistance of its movements resulting from the pollution of the VTG turbocharger mechanism with the turbine steering wheel positioner, with variable geometrical parameters.
EN
In this study, an experiment was conducted to examine the AVL research diesel engine using two kinds of waterdiesel (W-D) fuel microemulsions. These W-D mixtures contained 3.5 and 7.0% by volume (%, v/v) of distilled water dispersed in regular diesel fuel meeting the requirements of the EN590 standard. The engine was tested under the conditions of low, moderate and higher loads. This research was focused on the emission characteristics of nitrogen dioxide (NO2 ) and nitrogen monoxide (NO). Cumulative emission of NOx was also analyzed before being further discussed. The obtained results of this study showed that the addition of distilled water to the regular diesel fuel has a minor effect on the variation of the nitrogen oxides emission. It was confirmed that NO is the main component of NOx detected in the exhaust stream of the AVL engine fuelled with all tested fuels. It proves that the thermal mechanism of the nitrogen oxides formation was dominant in the combustion process. Moreover, it was found that the addition of water dispersed as microemulsion in diesel fuel had a minor effect on the reduction of the NOx emission.
EN
The paper reports a computer model for simulating dynamic responses in fuel rail of aircraft diesel engine. The fuel system was designed for use in a two-stroke compression-ignition engine with opposite pistons. The methodology of building a fuel system model in the AVL Hydsim program and the results of simulation studies were presented. Determination of dynamic phenomena in the fuel rail required the construction of a model of the entire supply system. It is a common rail system with a three-section positive displacement pump and electromagnetic fuel injectors. The system is also equipped with a PID regulator to maintain the present pressure in the fuel rail. For the purposes of the research, two structures of the fuel rail were developed. They differ in dimensions, spacing of the outlet ports and location of the high-pressure connection. The research allowed determining the interactions between the geometry of the fuel rail and the supply method with the fuel pressure and injector mass flow rate. This will optimise the design of the fuel rail for the three-cylinder engine power supply system.
EN
This paper investigated the impact of the exhaust gas recirculation on the concentration of selected harmful chemical compounds from the AVL 5402 research diesel engine powered with diesel fuel (DF) and compressed natural gas (CNG). The engine was operated in the dual fuel mode. It means that the engine was conventionally fuelled by regular diesel fuel and simultaneously by CNG dosed into the inlet pipe. The necessary tests were carried out for the mixtures containing 30, 50 and 70% of CNG (by energy content) in the total chemical energy delivered together with diesel fuel (DF) into the combustion chamber. The research was conducted for the stationary conditions of the engine operation at 1200 rpm and constant 1004 Joules of a fuel chemical energy delivered in each cycle into the combustion chamber. Under such conditions, the impact of the EGR rate changed in range of 0–50% on the emissions of selected unburned hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx) as well as particulate matter (PM), was evaluated. The obtained results confirmed that the EGR system is effective in the reduction of the NOx formation for all tested fuel mixtures. Nevertheless, it was found that the addition of CNG combusted in the diesel engine generates more harmful pollutants in comparison with diesel fuel. However, in some cases the concentration of NOx as well as PM was comparable or lower. It suggests that the combustion of CNG in diesels allows achieving environmental benefits. In this case, further optimization of the engine fuel supply system is necessary.
EN
The paper presents the research results of the AVL diesel engine powered with microemulsion fuels. In particular the emission of soot particles from the engine operated under stationary conditions was investigated. The necessary tests were carried out for two microemulsions containing 3.5 and 7% by volume of distilled water dispersed in diesel fuel with necessary surfactants/cosurfactants, i.e. Crillet-6/Span-20. Both tested microemulsions contained similar water micelles size distribution with average dimension of 18 nm. The results of the investigation confirmed that the combustion of tested water – fuel microemulsion in the AVL research engine reduces the emission of soot particles even by 50% in comparison with the diesel fuel.
EN
The paper presents problems of limitation the nitrogen oxides emission from marine diesel engines. The emission of noxious substances from combustion of marine fuels is restricted in respect of the atmosphere protection, International Maritime Organization (IMO) regulations and others. The IMO requirements were determined by time of being in force. The first tier started in 2000 year, the second in 2011, the third is being valid from 2016 on USA waters and in some chosen port areas (from 2021 will be obligatory on Baltic Sea, North Sea and English Channel) and it is a necessity to comply those last requirements. In case of NOx – between the first and second tier the emission was limited 20%, while the third step was limited 80% of the first one. This is a very great challenge, because in nowadays marine diesel engines and marine heavy and diesel oils generally applied, it would seem impossible comply those requirements. It was formed environmental controlled areas of NOx emission (ECA) and they will extend. Governments of some countries (USA, Norway) were introduced on own territorial waters the requirements of NOx and SOx emission. In case of exceeding the limits (or a lack of the proper certificates) it was imposed an ecological charge (a form of tax) or the interdict of entrance on regulated water zones. In the paper it was given an attention to the new challenges for engine producers and ship-owners of fulfilling tier 3 standards or search new substitute solutions. The applying solutions for nitrogen oxides emission limitations cause the decreasing of engine efficiency and increasing the fuel consumption (and carbon dioxide emission) up to ten percent. Due to regulations of marine environment protection they generate additional investment and operation cost for ship-owners and charterers.
PL
W artykule przedstawiono problemy ograniczania emisji tlenków azotu z okrętowych silników wysokoprężnych. W celu ochrony atmosfery przed emisją szkodliwych substancji z procesu spalania paliw okrętowych wprowadzono regulacje Międzynarodowej Organizacji Morskiej (IMO) i inne. Wymagania IMO określają czas wejścia w życie (obowiązywania). Pierwsze ograniczenie emisji tlenków azotu (Tier 1) obowiązuje od 2000 roku, drugie (Tier 2) od 2011, natomiast trzecie (Tier 3) obowiązuje od 2016 roku na wodach amerykańskich i wybranych obszarach portowych (od 2021 roku będzie obowiązywać na Morzu Bałtyckim i Północnym oraz Kanale La Manche) oraz zachodzi konieczność spełnienia tych wymagań. Dla tlenków azotu (NOx) – pomiędzy pierwszym a drugim limitem jest różnica 20%, podczas gdy trzeci limit jest o 80% mniejszy od pierwszego. Jest to wielkie wyzwanie, ponieważ w okrętowych silnikach wysokoprężnych stosuje się paliwa ciężkie i oleje napędowe, wydaje się niemożliwe spełnienie tych wymagań. Utworzono obszary kontroli emisji (ECA) tlenków azotu i te obszary będą się powiększać. Rządy niektórych krajów (USA, Norwegia) wprowadziły własne wymagania na ich wodach terytorialnych odnośnie emisji tlenków azotu i tlenków siarki. W artykule zwrócono uwagę na nowe wyzwania dla producentów silników i armatorów statków w celu spełnienia standardów emisji w limicie Tier 3 lub poszukiwania innych równoważnych rozwiązań. Stosowane rozwiązania ograniczenia emisji tlenków azotu zmniejszają sprawność silników oraz zwiększają zużycie paliwa (i emisji dwutlenku węgla) nawet o dziesięć procent. Z powodu wprowadzenia regulacji chroniących środowisko morskie, generują one dodatkowe koszty inwestycyjne i eksploatacyjne dla armatorów i czarterujących.
11
Content available remote Research and FEM analysis of the injection pump shaft for diesel engines
EN
The paper presents the methodology for designing the drive shaft of the injection pump for diesel engines with cylinder numbers of 2, 3, 4, 6 and power from 2,5 kW to 52 kW per cylinder using the finite element method (FEM) and experimental research. The pump is the original solution of the authors. The shaft is the basic part of the pump with a complex structure. In order to assess the state of stress in the shaft, the analytical FEM was used and experimental tests were carried out, subjecting the shaft to twisting with the design torque resulting from the transferred power. Experimental research confirmed the results of numerical calculations and the correctness of the adopted solution. In order to evaluate the maximum load capacity of the shaft, destructive tests were carried out, charging it with increasing torque until visible plastic deformations occurred. This condition occurred at a time twice as high as the maximum anticipated moment in operation.
PL
W pracy przedstawiono metodykę projektowania wału napędowego pompy wtryskowej do silników wysokoprężnych o liczbie cylindrów 2, 3, 4 i 6 oraz mocy od 7,5 do 57 kW na cylinder, z wykorzystaniem metody elementów skończonych (MES) i badań eksperymentalnych. Pompa jest oryginalnym rozwiązaniem autorów. Wał jest podstawową częścią pompy o złożonej strukturze. Do oceny stanu naprężenia w wale zastosowano metodę analityczną MES oraz przeprowadzono badania eksperymentalne, poddając wał skręcaniu momentem obliczeniowym wynikającym z przenoszonej mocy. Badania eksperymentalne potwierdziły wyniki obliczeń numerycznych i poprawność przyjętego rozwiązania. Aby ocenić maksymalną nośność wału, przeprowadzono badania niszczące, obciążając wał rosnącym momentem skręcającym do wystąpienia widocznych odkształceń plastycznych. Taki stan pojawił się przy momencie dwukrotnie większym w stosunku do maksymalnego momentu przewidywanego w eksploatacji.
12
Content available Turbocharging the aircraft two-stroke diesel engine
EN
The power and efficiency of a two-stroke engine strongly depends on the efficiency of the scavenging process which consists in removing the rest of the exhaust gases from the cylinder and filling it with a fresh charge. The quality of the charge exchange process is significantly influenced by the construction of the intake system. The paper presents a zero-dimensional model of the aircraft two-stroke opposed-piston diesel engine with two variants of the intake system: with a mechanical compressor and a turbocharger connected in series with a mechanical compressor. Simulation studies of the developed cases were carried out in the AVL BOOST software. For the defined engine operating points, its performance was compared for different designs of the intake system. It was confirmed that the use of a turbocharger with a mechanical compressor extends the range of operating at high altitudes.
EN
The measurement of combustion pressure relies on connecting a pressure sensor to a four-stroke marine engine cylinder by a channel led out from the engine cylinder. The geometry of the channel distorts the results of combustion pressure measurements. The purpose of the work is to create a model of combustion processes in engine cylinders. The model uses a mathematical description of the indicator channel on one of the engine cylinders. The input data to the model and the data necessary for its verification came from the direct measurements on the research facility. The test object was a four-stroke Sulzer 3AL25/30 engine loaded by an electric power generator. During calculations, different diameters and lengths of measurement channel were simulated. The obtained results allowed to formulate the conclusion that the geometry of the measurement channel has a significant impact on the measurement results. The increase of the length of the measuring channel as well as the diameter of the channel causes disturbances in the measurement of the maximum pressure.
EN
This publication is the next part of the article “The influence of cetane-detergent additives in diesel fuel increased to 10% of RME content on energy parameters and exhaust gas composition of a diesel engine”. The cause-effect analysis of the phenomena related to the impact of 3 additive packages used in diesel oil with RME content increased to 10% (compare to standard diesel fuel with 7% of RME) was described. The basis for the analysis of the impact of the tested fuels on energy parameters and composition of exhaust gases were the parameters of indicator diagrams and heat release parameters. It was found that the first set of additives affects the delay of auto-ignition of fuel and kinetic fuel combustion speed only at low engine loads. In this range of engine operation the NOx concentration in the exhaust gas is low and besides there is a large of EGR. The second additive package was operated at high engine loads but its impact on the lower self-ignition delay was quantitatively small. Therefore, in the third packet of additives, the amount of additives used in the second packet was doubled. Then a satisfactory shortening of the self-ignition delay and reduction of the max rate of kinematic heat release was achieved as a reason of a reduction of NOx concentration in the exhaust up to 8% (compared to the reference fuel).
EN
This paper presents the results of experimental studies of the opposed-piston diesel engine. This engine was designed during one of the stages of the research on a new-type drive unit for gyrocopter applications. In order to conduct research, a special test stand as well as control and measurement systems were developed. As part of the work on the engine, the fuel injection system, engine temperature control system and measurement systems were designed. In addition, a computer program has been developed for the fuel injection system control (injectors, valves fuel pressure regulators). The paper presents the results of the preliminary tests for a single value of engine speed (1500 rpm) and three values of load defined by torque. The measured value of the indicated pressure made it possible to calculate the maximum pressure. The results obtained from the bench tests were analyzed.
EN
The paper presents an analysis of the constructions of oil pumps for an aircraft compression ignition engine. It is a two-stroke liquid-cooled engine with a power of 100 kW. The system has 3 cylinders and 6 opposed pistons. The paper estimates the required oil pump capacity to make the engine components well-lubricated. Next, automotive oil pumps for diesel engines are analyzed to select a correct pump for aircraft diesel engine applications. Three pump constructions of different constructions and dimensions of a rotor were select-ed. A measurement bench was designed and built to test these oil pumps in the range of pump shaft speeds from 0 to 4500 rpm and volumetric flow rate up to 150 l/min. The bench also enables stabilization of oil temperature at the required level within the range from 30 to 120oC. In addition, flow resistance through engine slide bearings was simulated by changing the position of a throttling valve at the pump output to regulate pressure in the range of 0-700 kPa. The obtained capacity characteristics of individual pumps versus on oil pressure and temperature allowed us to find an appropriate oil pump to make individual engine nodes well-lubricated.
17
EN
The article presents an analysis of the design of cooling liquid pumps for a compression-ignition aircraft engine. A 100 kW twin-charged, two-stroke, liquid-cooled engine has 3 cylinders and 6 opposed-pistons. In the first part of the study, the amount of heat needed to be removed by the cooling system was estimated to obtain the required volumetric flow rate. Then, the design of automotive cooling liquid pumps for compression-ignition engines with a Common Rail power supply system and power of about 100 kW was analyzed. The aim of the analysis was to select a suitable pump for applications in the aircraft compression-ignition engine. 5 constructions of different shape, diameter and width of the working rotor were selected. The pressure and volume flow rate were determined for a given rotational speed of the pump on a specially built stand. The operation maps of individual pumps were created to select the most efficient types of pumps.
EN
The paper presents an analysis of the possibility of using a common rail pump to supply an aircraft compression-ignition engine. It is an engine with a two-stroke cycle, three cylinders, opposing pistons and 100 kW power. Its each combustion chamber is supply by one or two injectors controlled by electromagnetic valves. In order to assess the possibility of using a common rail pump, four high-pressure pumps were tested on a bench. They are piston pumps differing in the number and geometry of their pumping sections. The analysis included the pumping output, the torque on the pump drive shaft and the power needed to drive the pump. The weight and overall dimensions of the pump were also considered, including the arrangement of the pumping sections and the way the drive is transmitted. The research allowed to optimize the engine power supply system depending on fuel demand and the way the pump is mounted on the engine.
EN
In the paper researches of influence of using catalyst and polar additives on engine performance and emission of exhaust were carried out. The tests were made on diesel engine DuraTorq-TDDi/TDCi 16v with a capacity of 1998cm3 produced by Ford company. Two additives were investigated: FMAX - catalytic additive to fuel and HDOS - polar additive to lubricating oil in different proportions. The results indicated that using tested additives has a positive effect on exhaust composition (lower concentrations of nitrogen oxides, soot and carbon monoxide) and also decreased fuel consumption.
EN
This paper dals with design of optimized electronic control for diesel engines for all-terrain vehicles. In paper the detailed proposal of control algorithm, as well as procedure for turbocharger innovation is described. Designed optimization algorithm is verified on real Land Rover Defender vehicle. In last part of paper, the measurements on electrodynamic dynamometer are discussed.
PL
Niniejszy dokument przedstawia projekt zoptymalizowanego sterowania elektronicznego dla silników wysokoprężnych do pojazdów terenowych. W pracy opisano szczegółową propozycję algorytmu sterowania, a także procedurę dotyczącą innowacji turbosprężarki. Zaprojektowany algorytm optymalizacyjny jest weryfikowany na prawdziwym pojeździe Land Rover Defender. W ostatniej części artykułu omówiono pomiary elektrodynamicznego dynamometru.
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