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1
Content available A method of rotary engine performance prediction
EN
. The rotary engine mainly developed for the automotive industry by the NSU corporation is currently used in unmanned aircraft, transportable generators and small watercraft. In the early stage of the engine development, the simulation of the performance characteristics is advisable. The 3D CFD engine simulation is highly expensive in terms of CPU time demand and requires a high level of optimisation to provide adequate data. This method can be used later in the development and fine engine tuning. For the design of the prototype 1D, simulation is being used as a tool to compare various designs of the engine. While the current commercially available software (GT-suite, Ricardo Wave, etc.) is being improved marginally, the functionality of the software is being tested on the piston reciprocating engines. This paper explores the possibility of the algorithms of such a software to be used on the rotary engine thermodynamic simulation and provides an approach to design a simulation model that can be solved by the software to predict the performance characteristics of the engine prototype.
EN
In this paper, the results of modeling of the burning process in the piston engines whose working process is realized on the basis of various conceptual approaches are presented: in diesel with direct injection of the fuel; in a gas engine with spark ignition; and in a two-fuel engine (in the gas-diesel), where the mixture of natural gas and air ignites with the help of the fuse dose of the diesel fuel. The models of burning based on the different in-principle approaches are analyzed and used. Verification of the models is performed by a comparison of the results of modeling with the experimental diagrams. The specific values of the empirical coefficients, used in modeling of the burning proces in the engines under study, are determined. The practical recommendations on the choice of the burning model depending on the working process conception are given.
EN
The article presents an analysis of research on a series of passenger vehicles equipped with diesel and spark-ignition engines of modern generation. These studies show the attempt to determine the consistency of the measurement results presented by the electrical motor with respect to the external direct measurements determining the level ecological driving unit such as a gas analyzer. The premise of this material is to assess the suitability of the read actual parameters sent by the ECU as the data source the level of organic vehicle, for example. The test for diagnostic station with annual regular reviews. The inspiration for the material was the attempt to determine the sensitivity of the self-diagnosis system of the propulsion unit, which correctness of the diagnosis itself is one of the criteria of the positive periodic test guidelines.
EN
Internal combustion engines have to be supplied with adequate amounts of fuel and air. The required amount of fuel and air is determined by the engine controller to guarantee that the fuel reaching the cylinder is burned effectively and that the composition of exhaust gas meets standard requirements. The air supplied to an internal combustion engine has to be adequately filtered because impurities reaching the engine can accelerate the wear of engine components. The air intake system features a filtering partition which captures impurities and prevents them from reaching the engine. However, the filtering process decreases the rate at which cylinders are filled with fresh air, which can compromise engine performance. Therefore, effective solutions are needed to ensure that the flow of filtered air does not significantly decrease the volumetric efficiency of cylinders. This study presents a design concept of a device for measuring pressure in the air intake system in front of and behind the filtering partition. The proposed device can be useful for measuring filter wear. A prototype of the proposed device was built and tested on several air filters. To eliminate throttle valve impacts, the device was tested in a compression ignition engine. The results of the conducted tests demonstrated that the device correctly measured air flow. The conducted measurements also revealed that the presence of impurities in the air filter induced differences in pressure in the air intake system in front of and behind the filtering partition. The maximum air flow resistance in a clogged filter could be even 100% higher than in a brand new filter.
EN
Data of energy economy of battery electric vehicles without a range extender internal combustion engines (BEV) and with a range extender internal combustion engine (BEVx) are reviewed and integrated with simulations by models. A BEV with an on-board, high efficiency, electricity generator based on a positive ignition (PI) internal combustion engine (ICE) is then proposed as a way to improve the uptake of the BEV improving their range and performance as well as their economic and environmental impact. The small ICE, that is working continuously, stationary, fixed load and speed, and the generator similarly optimized for a single point operation, permit an efficiency fuel chemical-to-electric approaching 50%. This is much better than producing electricity centralized from combustion fuels (average efficiency with included distribution and recharging losses at about 30%), and it does not require any electric recharging infrastructure. Simple but reliable extrapolations from the production BEV and BEVx of different battery capacity on the same vehicle platform, plus the simulations, demonstrate that this BEVy may deliver miles-per-gallon (MPG) working gasoline 13% better than any present plug-in-hybrid-electric-vehicle (PHEV) currently available, and MPGe (MPG-equivalent) working electric 12% better than the existing BEV on the same platform with a larger battery pack and no range extender, or 27% better than the BEVx on the same platform with a larger battery pack and range extender. Finally, this BEVy may permit a range over 600 miles with 10 gallons of gasoline onboard, in line with the best PHEV currently available.
PL
W artykule analizowano możliwości wykorzystania wewnętrznego silnika spalinowego o dużej efektywności do ładowania akumulatora. Możliwości te analizowano dla różnych modeli samochodu. Porówanno też tego typu rozwiązanie z samochodami hybrydowymi.
6
Content available remote Diagnostic and reliability model of an internal combustion engine
EN
The article presents a diagnostic and reliability model of an internal combustion engine that allows to assess the reliability status of the engine’s systems for a two-state model of operation and maintenance: functional - failed. The proposed diagnostic model is a qualitative-quantitative probabilistic model combining the reliability states of the engine systems with the values of the vibroacoustic diagnostic signal parameters. The conducted diagnostic and reliability experiments and simulation tests showed that based on the developed diagnostic and reliability model, it is possible to determine the reliability states of the engine.
EN
To estimate the effect of the axial movement of piston rings in the piston grooves on the blow-by in the internal combustion engine (ICE) by an experiment- calculated method. This contributes to the development of practical recommendations for the further improvement of the engine ring seal designs. Abstract theorems were used when modelling the effect of the axial movement of piston rings in the piston grooves on the blow-by in an ICE. They are based on the fundamental theory of heat engines, thermodynamics and hydraulics. The ICE running was analysed using design-theoretical research methods. The effect of the axial movement of piston rings in the piston grooves on the blow-by in the ICE was established. This creates prerequisites for a more accurate assessment of their sealing capacity and for ways to further improve them. Calculated dependences for computing the blow-by depending on the positional relationship of the rings in the piston grooves were obtained. The dependences of gas escapes on the engine crankshaft speed were obtained, which is especially important for idling modes by which one can judge the dynamic stability of the ring seal and solve the problems of improving its service properties. The calculated dependences for evaluation of the blow-by depending on the positional relationship of the rings in the piston grooves and their respective possible gas flows in the ring seal were obtained for the first time. The practical method for estimating the dynamic stability of the ring seal by decencies of gas escape on the crankshaft rotation speed in ICE was proposed.
EN
The article presents the results of the investigations of turbocharger shaft bearing using different kinds of lubrication conditions (dry friction and lubrication with different kind of oils). In particular, the wear of the turbocharger shaft surface was evaluated. One of the most frequent failures is the seizure of the turbocharger shaft in the slide bearing, causing its rotation, which leads to destruction of the assembly and costly repairs. On the basis of the conducted tests, it was found that the average value of representative breaks surface on the turbocharger shaft are reduced using of a less viscous oil. Similar situation was seen using new oil instead overworked oil – it had an influence on the value of diameter of breaks.
9
Content available Cavitation defects in farm vehicle engines
EN
The article identifies and analyses selected examples of cavitation erosion occurring in farm tractor engines and their systems at different mileages. The analysis has been carried out on the basis of known theoretical rudiments of this phenomenon. The paper presents photographs from maintenance work selected by the authors, which illustrate the discussed matter graphically. There is a discussion on how to prevent cavitation phenomena occurring in coolant, which induce engine defects.
PL
W artykule poddano identyfikacji i przeanalizowano wybrane przykłady występowania erozji kawitacyjnej w silnikach ciągników rolniczych i ich układach, po różnych przebiegach. Analizę przeprowadzono na podstawie znanych podstaw teoretycznych tego zjawiska. Zamieszczono zdjęcia wybrane przez autorów z pracy serwisowej, które graficznie przedstawiają zagadnienie. Omówiono również jak zapobiegać zjawiskom kawitacji w cieczy chłodzącej powodującej uszkodzenia silników.
EN
Literature review on flow acoustic methods and materials of an automotive muffler. A car is judged comfortable also depending on the acoustic level transmitted inside, and a thorough knowledge of acoustics of ducts and mufflers is needed for the design of efficient muffler configurations. Unstable exhaust gas at high temperature flowing from internal combustion engine manifold may cause of noise and vibrations conflicting with the high standard of acoustic comfort requested by this kind of vehicle. The basic gaols are to define most important methods to identify noise occur from the motion of fluid in case of turbulent model. Materials properties like velocity, temperature, thermal conductivity and density have been technical presented in this work.
EN
The effectiveness of work of an internal combustion engine can be assessed by means of the energy efficiency: theoretical, internal and effective... In the problem regarding the efficiency of obtaining a work from the tested SI engine, the theoretical Seiliger-Sabathe cycle was adopted as a reference model for the real engine cycle. For comparison, the OTTO cycle was also analysed. The engine indicating allows direct determination only of internal work. However, determining the work of the theoretical cycle first requires solving the problem of selecting the parameters of the theoretical cycle, according to the real cycle of the engine (inverse problem). In order uniquely to determine the course of the theoretical Seiliger-Sabathe cycle, it is necessary to determine the parameters of the starting point and the heat distribution number. The selection of the theoretical cycle for the real cycle, within the scope of determining the number of heat distribution, is to some extent of a contractual nature. Therefore, the problem of determining the number of heat distribution was solved by two own original methods. A comparison of the real cycle with the theoretical cycle determined for it is presented.
PL
Technologia ORC (Organic Rankine Cycle – Organiczny obieg Rankine’a) postrzegana jest jako jedna z najlepszych metod pozwalających na przekształcenie nisko– i średniotemperaturowych zasobów ciepła odpadowego w energię elektryczną. W niniejszej pracy przedstawiono przykłady wdrożeń układów ORC w zakresie wykorzystania ciepła odpadowego w przemyśle. Przeprowadzono również szczegółową analizę współpracy układu ORC z silnikiem spalinowym zasilanym gazem z odmetanowywania kopalni. Na tym przykładzie omówiono kluczowe zagadnienia technologiczne i ekonomiczne z uwzględnieniem korzyści energetycznych i środowiskowych.
EN
The ORC (Organic Rankine Cycle) technology is perceived as one of the best methods for transforming of low– and medium-grade waste heat resources into electricity. This paper presents examples of the implementation of ORC systems in the field of waste heat utilization in industry. A detailed analysis of the cooperation of the ORC system with the combustion engine fueled with coalbed methane was also carried out. On this example, key technological and economic issues were discussed, including energy and environmental benefits.
EN
The mathematical description of combustion process in the internal combustion engines is a very difficult task, due to the variety of phenomena that occurring in the engine from the moment when the fuel-air mixture ignites up to the moment when intake and exhaust valves beginning open. Modeling of the combustion process plays an important role in the engine simulation, which allows to predict incylinder pressure during the combustion, engine performance and environmental impact with high accuracy. The toxic emissions, which appears as a result of fuels combustion, are one of the main environmental problem and as a result the air pollutant regulations are increasingly stringent, what makes the investigation of the combustion process to be a relevant task.
EN
The ecological issues and the depletion of crude oil, has led the researchers to seeking for non-petroleum based alternative fuels, along with more advanced combustion technologies, and after-treatment systems. The use of clean alternative fuels is the one of the most perspective method that aiming at resolving of the said issues. One of the promising alternative fuels that can be used as a clean high-efficiency compression ignition fuel with reduced of toxic emissions is dimethyl ether (DME). Moreover, it can be produced from various feedstocks such as natural gas, coal, biomass and others. This article describes the properties and the potential of DME application on the combustion and emission reduction characteristics of the compression ignition engines.
EN
The modification of the downsizing trend of internal combustion engines towards rightsizing is a new challenge for constructors. The change in the displacement volume of internal combustion engines accompanying the rightsizing idea may in fact mean a reduction or increase of the defining swept volume change factors and thus may affect the change in the operating characteristics as a result of changes in combustion process parameters - a research problem described in this publication. Incidents of changes in the displacement volume were considered along with the change of the compression space and at the change of the geometric degree of compression. The new form of the mathematical dependence describing the efficiency of the thermodynamic cycle makes it possible to evaluate the operation indicators of the internal combustion engine along with the implementation of the rightsizing idea. The work demonstrated the invariance of cycle efficiency with different forms of rightsizing.
EN
The aim of the work is to check the possibility of applying the Monte Carlo method to the calculation procedure of internal combustion engines. This has been accomplished by modifying existing algorithms in such a way that the variables responsible for the main parameters of the engine are selected in a random manner using Solver written in Microsoft Excel. It turns out that this method can actually be implied, however, it has some limitations related to the high complexity of calculations.
EN
The article presents CFD (Computational Fluid Dynamics) analysis of the Ferrari 348 sports car intake system for three variants of air intake speed to the system. The article contains an analysis of the distribution of velocities and static pressures. In addition, local velocity and flow in the filtration chamber were investigated. The influence of air velocity at inlet to the intake system on the abovementioned parameters was determined. The analysis is a prelude to the study of wave phenomena occurring in the intake system, affecting the fill factor of the cylinders. Ansys Fluent software was used for analysis.
PL
W artykule przedstawiono analizę CFD (obliczeniowej dynamiki płynów) układu dolotowego samochodów sportowych Ferrari 348 dla trzech wariantów prędkości wlotu powietrza do układu. Artykuł zawiera analizę rozkładu prędkości i nacisków statycznych. Ponadto zbadano lokalną prędkość i przepływ w komorze filtracyjnej. Określono wpływ prędkości powietrza na wlocie do układu dolotowego na wyżej wymienione parametry. Analiza jest wstępem do badania zjawisk falowych zachodzących w układzie dolotowym, wpływających na współczynnik wypełnienia cylindrów. Do analizy użyto oprogramowania Ansys Fluent.
18
Content available CFD analysis of the Ferrari 348 GTC intake system
EN
The article presents CFD (Computational Fluid Dynamics) analysis of the intake system of a Ferrari 348 GTC sports car. With this system, an adequate amount of air is supplied relative to the current demand for fuel combustion. The air demand of a given engine was determined, then analyzes were carried out. The article contains an analysis of the velocity distribution: total velocities, angular velocities and static pressure distribution. In addition, local velocity and flow in the filtration chamber were determined along with the flow directions and returns as well as power lines. The cycle impact on the temperature, locations of the highest speed drop, increase in turbulence, the largest pressure differences, and modulus of elasticity were determined. This information allows to assess whether there are no unwanted phenomena occurring in the system, such as flow disturbances. The Ansys Fluent software was used for analysis.
PL
W artykule przedstawiono analizę CFD (Computational Fluid Dynamics) układu dolotowego samochodu sportowego Ferrari 348 GTC. W tym systemie dostarczana jest odpowiednia ilość powietrza w stosunku do bieżącego zapotrzebowania na spalanie paliwa. Określono zapotrzebowanie na powietrze dla danego silnika, a następnie przeprowadzono analizy. Artykuł zawiera analizę rozkładu prędkości: prędkości całkowite, prędkości kątowe i rozkład ciśnienia statycznego. Dodatkowo wyznaczono lokalną prędkość i przepływ w komorze filtracyjnej wraz z kierunkami przepływu i powrotami oraz liniami energetycznymi. Oceniono wpływ cyklu na temperaturę, lokalizację największego spadku prędkości, wzrost turbulencji, największe różnice ciśnień i moduł sprężystości. Informacje te pozwalają ocenić, czy w systemie nie występują niepożądane zjawiska, takie jak zakłócenia przepływu. Do analizy wykorzystano oprogramowanie Ansys Fluent.
EN
Abstract In this article Authors present the continuation of the calculations for theoretical ACC engine cycle, considering additionally “VCR function” – changeable compression level. For this purpose the self-acting volume change, realized by ACC system, was used. The ACC system was adjusted appropriately to control the compression level. The analysis is based on three cases, representing delayed, premature and optimal reaction of ACC system. Reactions are presented in form of plots with indicated pressure in the combustion chamber. As the result of the conducted analysis and interpretation of obtained graphs, the calculation approach of compression ratio for ACC presented in previous article is being challenged. For the optimal reaction of ACC system, the theoretical operation schematics are devised and presented in the key points of the work. Based on the schematics, the values of theoretical efficiency were calculated for different cycles of theoretical ACC engine, in which regulation of compression ratio takes place. Moreover, the presented analysis includes graphs with optimal courses of indicated pressure for significantly different work parameters of ACC engine, showing its regulation possibilities. Also the time scaled graphs (with millisecond as basic time unit) are presented to show the possibilities of dynamic ACC systems, which are comparable with the combustion time (from 3 to 0,5 ms). In this paper the general discussion is started about the compression ratio in more complex kinematic systems including ACC.
EN
The paper presents the results of experimental and numerical studies of contact interaction of rubbing bodies after technological processing – discrete hardening. Experimental studies were carried out on the example of the contact pair "crankshaft of an internal combustion engine - liners". Numerical simulation was carried out using generalized parametric modeling of complex mechanical systems. To determine the stress-strain state of the elements being studied, the finite element method was chosen. Based on the results of the conducted studies, the efficiency of the proposed method of technological processing of contacting bodies – discrete hardening - was demonstrated.
PL
W pracy przedstawiono wyniki eksperymentalnych i numerycznych badań kontaktu ciał trących po obróbce technologicznej - dyskretnym utwardzaniu. Badania eksperymentalne przeprowadzono na przykładzie pary kontaktowej "wał korbowy silnika spalinowego - wkładki". Symulacja numeryczna została przeprowadzona przy użyciu uogólnionego parametrycznego modelowania złożonych układów mechanicznych. Aby określić stan naprężenie-odkształcenie badanych elementów, wybrano metodę elementów skończonych. Na podstawie wyników przeprowadzonych badań wykazano skuteczność proponowanej metody technologicznej obróbki ciał stykowych - dyskretne utwardzanie.
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