Wyniki wyszukiwania - Biblioteka Nauki

1

Cooling of removable battery pack in the electric car

100%

Mitianiec W.

Journal of KONES

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2013

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tom Vol. 20, No. 2

277--284

EN

The thermal management system is the one most important unit in the electric car which controls temperature of electric devices by obtaining a stability of their operation in different load and ambient conditions. For the other side the removable pack installed in the closed cradle for easier service during exchange of the modules should be cooled by the air. It is also better for safety during exploitation for the vehicle parts and people. The paper presents the proposal of ventilation of battery packs, assumptions of the battery pack cooling system, mathematical model of heat exchange and graphical results obtained from simulation carried out using the CFD program. During modelling it took into account two models: two-dimensional and three-dimensional for evaluation of the air flow and cooling rate of the battery modules. It was assumed four modules in one row of the cradle with total electric capacity above 4 kWh. The paper shows geometry of the whole battery unit with ventilation passages in 3D configuration. The aim of the work was determination of thermal parameters of the battery modules cooled by the air flow in the close chamber. The proposed cooling model of the cradle with air flow caused by fans in the pipe inlet shows that it is not possible to decrease temperature in the same way of each battery modules.

2

Study of stratification of CNG mixture in a high charged SI engine

100%

Mitianiec W.

Journal of KONES

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2006

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tom Vol. 13, No. 2

323-333

EN

The burning of CNG mixture can occur in very small range of the compression pressure and lean mixture composition. The increased compression pressure requires a big pressure of CNG injection Even for lean mixtures the maximum combustion pressure reaches value near 200 bars. For very lean mixtures and higher compression ratios the misfire occurs, on the other hand for rich mixtures and high compression ratios the detonation is observed. For part load the fuel is injected during the compression stroke, which should form a bigger concentration of fuel near spark plug. The timing of injection should correlate with the piston position BTDC and engine speed in order to enable the adequate stoichiometric mixture near the spark plug during the ignition. The stratification of the charge depends on the location of the injector and the angles of injection nozzles and on the shape of the piston crown. The motion of the injected gaseous fuel required the adequate profile of piston head to turn the fuel stream directly to the spark plug. The flat piston causes that small part of fuel reaches the cylinder cavities and the increase of HC is observed. The paper performs results of calculations of the work engine parameters for 3 types of the piston shapes. The calculations were carried out in the 3-dimensional space with full engine geometry for the same engine speed and injection time. The simulations of CNG injection and combustion process were carried out for motorcycle engine SUZUKI DR-Z400S

3

Optimization of the rich mixture injection system in two-stroke engines

100%

Mitianiec W.

Journal of KONES

|

2006

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tom Vol. 13, No. 3

213-224

EN

Two-stroke engines used in small applications, in order to fulfill the emission requirements, should be equipped with a direct injection system or pneumatic rich mixture injection system. The FAST system in the Piaggio engines is based on the two-throat carburetor. Till now the Piaggio company has not published the physical processes taking place in such engines. The author has carried out the deep study of the process of rich mixture injection by an additional compressor and the results of calculations are presented in the paper. The simulation was done by using of the own computer program based on the mathematical model taking into account the unsteady gas flow of semi-perfect gas, the changed parameters of engine geometry and controlled parameters. The paper includes description of the fuelling system, mathematical model, calculation algorithm, results of calculations for different controlled parameters and comparison with other systems. The FAST computer program enables to define the characteristics of the cylinder charge, engine power, fuel consumption and exhaust gas composition. The simple mechanical fuelling system without electronic participation enables to apply it for the engines driven the small vehicles. However the drive of the compressor by tooth belt from the engine crankshaft decreases the total engine power about 20%.

4

Termochemiczny model katalizatora w układzie wylotowym silnika dwusuwowego

100%

Mitianiec W.

Journal of KONES

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2000

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tom Vol. 7, No. 1-2

404-413

PL

W artykule został podany l-wymiarowy model matematyczny przepływu gazów spalinowych o znanym składzie chemicznym przez reaktor katalityczny w układzie wylotowym silnika dwusuwowego. Model uwzględnia przenikanie spalin do ścianek monolitu pokrytego warstwą materiałów szlachetnych (Pt-Rd) oraz przepływ ciepła między warstwą gazu i ściankami. Reakcje chemiczne utleniania toksycznych składników spalin zachodzą na powierzchni ścianek monolitu. Bilanse masy i energii poszczególnych składników spalin w fazie gazowej i na powierzchni katalizatora określają działanie katalizatora. W silniku dwusuwowym uwzględnia się tylko redukcję tlenku węgla i węglowodorów oraz śladowych ilości wodoru. Zawartość tlenków azotu w spalinach jest wielokrotnie mniejsza niż w silnikach 4-suwowych. Podano główne reakcje chemiczne zachodzące w reaktorze katalitycznym silnika 2-suwowego z ilością wyzwolonego ciepła. Szybkość reakcji została określona za pomocą równań Arrheniusa ze stałymi podanymi w literaturze. Model jest szczególnie przydatny do badania zachowania się katalizatora w warunkach nagrzewania i małego obciążenia w warunkach niestacjonarnych. Zbudowany model matematyczny był podstawą do opracowania programu symulacyjnego. Podano przykładowe wyniki obliczeń oraz porównano z badaniami eksperymentalnymi.

EN

One-dimensional mathematical model of exhaust gas flow with known concentration of chemical species through catalytic reactor in an outflow system of two-stroke engine was described in the paper. The model takes into consideration diffusion of gas species to the wall of catalytic monolith covered with precious metal (Pt-Rd) and heat transfer between gas and walls. Reactions of chemical oxidation of toxic exhaust gas components take place on the monolith walls. The basis of the model is balance of mass and energy of individual exhaust gas species in gas phase and on catalytic walls. In a two-stroke engine only reduction of carbon monoxide, hydrocarbons and some of hydrogen is considered. NOX concentration in exhaust gas is several times less than in four-stroke engines. Main chemical reactions taking place in catalytic reactor of two-stroke engine with amount of heat release are given in the paper. Velocity of reaction rate was determined by Arrhenius equations with constants given in literature. The model is particularly useful for investigation of catalyser in warm-up and light-of state in unsteady conditions. The work out mathematical model was the basis for preparing simulation computer program. Example results of calculation from simulation were given in the paper and they were compared with experimental test.

5

A new concept of direct injection of fuel mixture

100%

Mitianiec W.

Journal of KONES

|

2001

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tom Vol. 8, No. 1-2

84-91

EN

In order to increase time required to vaporise all injected fuel, a new concept of preparation fuel mixture is proposed. Fuel is injected to separate chamber located near the cylinder and joined by two short pipes of small diameter. Connection between the cylinder and chamber are controlled by electronic valves. Hot gases are delivered to the chamber during expansion process with pressure about 3 bar. Fuel is injected to hot gases in the chamber assuring well preparation of mixture. Outflow valve ofthe chamber opens when exhaust port is closed to reduce fuel losses and jet of rich mixture is turned into spark plug. Only fuel dose is controlled at constant pressure and constant angle ofinjection process. Paper includes a description of the new system, mathematical model of exchange charge in the chamber and cylinder, injection process, simulation results ofphysical processes which occur in the cylinder and chamber. A diagram of the fuelling system explains a principle of work and figures show variation of gas pressure, temperature and vaporisation of fuel during crankshaft rotation. The system is designed for one-cylinder two-stroke engine, but can be applied also for multi-cylinder engines. The paper describes the first stage of work sponsored by Polish Scientific Committee.

6

Comparison of performance of two-stroke engine with catalytic converter

100%

Mitianiec W.

Journal of KONES

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2001

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tom Vol. 8, No. 1-2

129-137

EN

Applying of catalytic converter in exhaust system of two-stroke engine decreases significantly emission of toxic components but also reduces working parameters. Temperature of exhaust gases in exhaust pipes takes effect on behaviour of converter monolith and reduction of CO and hydrocarbon. In paper exhaust system witb converter located in the middle of tuned motorcycle exhaust system is examined and compared witb normal system. The paper includes description of physical processes occurring in exhaust pipe, mathematical model of unsteady gas flow, which take into account increase of gas friction in tbe monolitb. Results of simulation process and research work on test stand are shown in figures. Simulation enables optimisation ofwholeexhaust system at conservation of high temperature in tbe monolitb. In paper result of simulation (torque, fuel consumption, residual gas etc.) were given in comparison to original engine. Comparison of power and fuel consumption indicates on decreasing of workparameters of two-strokeengine witb catalyst at higher rotational speed.

7

Combustion process of direct injected water-coal mixture in diesel engine

100%

Mitianiec W.

Combustion Engines

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2016

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tom R. 55, nr 1

37--43

EN

The paper describes the problem of coal-water mixture combustion process in heavy duty diesel engines in the energetic sector application. In the future due to depletion of crude oil resources we have to foreseen another fuel for application in power plants. Large deposits of coal and lignite in the world enable to utilize these fuels in different thermal machines, especially in internal combustion engines. A carbon powder containing small molecules about 10–20 micrometers dissolved in water is good fuel for applying in large capacity engines in electrical plants. Aqueous emulsion of coal has possibility of good cooling of injectors cooling and has also good lubricity. Initial experimental tests done in the world indicate a higher thermal efficiency of engine fuelled by water coal emulsion than engine fuelled by diesel oil and also gas turbine driven by gas from coal gasification technology. The increased emission of CO2 can be reduced in the plants simply by chemical reduction. The paper explains thermochemical processes taking place in the engines during combustion process. The work parameters results obtained from calculations were compared with those obtained from CI engine fuelled by diesel oil. The paper is a certain challenge for finding a new fuel sources as a competition for crude oil and allows to get acquainted with new engine fuelling technology.

8

Modelowanie i symulacja redukcji NOXx w selektywnym reaktorze katalitycznym

100%

Mitianiec W.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

|

2014

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tom z. 1/97

89--100

PL

Praca przedstawia modelowanie i wstępne obliczenia działania redukującego tlenków azotu w selektywnym reaktorze katalitycznym (SCR) z ujęciem termolizy i hydrolizy czynnika redukującego urea (AdBlue). Pokazano wirtualny schemat układu reaktora wraz z model obliczeniowym ujmującym reakcje chemiczne hydrolizy i termolizy oraz reakcje redukcji z udziałem katalizatora między amoniakiem i związkami tlenowymi azotu. W pracy pokazano wyniki obliczeń stopnia redukcji poszczególnych tlenków azotu oraz zmiany temperatury wewnątrz reaktora i na wylocie z reaktora dla przyjętych wstępnie wartości parametrów wlotowych oraz przyjętej geometrii selektywnego reaktora katalitycznego. Obliczenia wykonano za pomocą programu GT-Power ver.7.3.

EN

The work presents modelling and initial calculations of reduction activity of nitrogen oxides in a reactor with Selective Catalytic Reduction (SCR) with taking into account the hydrolysis and thermolysis reactions of reduction medium such as urea (AdBlue. The virtual scheme of the reactor system is presented with the calculation model containing the chemical reactions of hydrolysis, thermolysis and surface reduction reactions between ammonia and oxygen compounds of nitrogen with a presence of the catalyst. The calculation results of reduction ratio of the particular nitrogen oxides and variations of temperature inside the reactor and in at outflow are presented for the assumed initial parameters of the exhaust gases and assumed geometry of the SCR reactor monolith. The calculations were carried out by means of GT-Suite program ver.7.3.

9

Modeling of heat recovery system in diesel particulate filter

100%

Mitianiec W.

Archiwum Motoryzacji

|

2010

|

tom Nr 4

287-300

EN

An additional energy for soot combustion is required for regeneration of particle filters (additional fuel or electric energy) after some period of the engine work as a result of closing of substrate pores by soot. The proposed method takes into account a self-regeneration of diesel particle filter by use of special heat recovery system. The paper shows one of possible design of DPF self-regeneration. The exhaust temperature behind the turbine and catalytic converter is very low and for an increasing of gas temperature before DPF and the heat from soot combustion can be used. The preliminary studies show a possibility of using the special DPF design with a heat recovery system. The paper presents the simulation results of such system and possibility of increasing the heat recovery ratio by change of geometry of DPF. The preliminary results of calculations show the possibility of increase of exhaust gases temperature in front of DPF about 20% which enables a continuous regeneration of DPF. The method enables to recovery some part of energy which is lost in the conventional DPF.

PL

Regeneracja filtra cząstek stałych wymaga dodatkowej energii w celu spalenia sadzy po pewnym czasie pracy, kiedy następuje zatkanie porów filtra. Innowacyjna metoda uwzględnia automatyczną regenerację filtra cząstek stałych przez zastosowanie specjalnego wymiennika ciepła. Artykuł przedstawia jedno z możliwych rozwiązań automatycznej regeneracji. Temperatura gazów spalinowych za turbiną i konwerterem katalitycznym jest bardzo niska i w celu zwiększenia tej temperatury przed DPF, wykorzystuje się do tego celu ciepło ze spalania sadzy. Wstępna analiza wykazuje możliwość zastosowania specjalnego wymiennika ciepła wbudowanego w konstrukcję DPF. Artykuł przedstawia wyniki symulacji numerycznej takiego systemu i możliwości wzrostu stopnia odzysku ciepła przez zmianę geometrii filtra cząstek stałych. Wstępne wyniki obliczeń wykazują możliwość wzrostu temperatury gazów spalinowych o około 20%, co umożliwia ciągłą regenerację filtra. Metoda ta umożliwia odzysk pewnej części traconej energii w konwencjonalnych filtrach cząstek stałych.

10

Modelling and simulation of working processes in Wankel engine with direct hydrogen injection system

100%

Mitianiec W.

Combustion Engines

|

2015

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tom R. 54, nr 2

42--52

EN

Wankel engines were very attractive in automotive sector almost forty years ago because of small dimensions, compactness, simple design, smoothness of engine work and lack of vibration caused by inertia forces. The disadvantage of such engine was very high pollution, especially of hydrocarbons and carbon monoxide and high fuel consumption. These disadvantages can be eliminated by applying of direct injection of hydrogen and in the aviation sector by applying of fuel with high octane number also at a direct injection system. The main objective of the work is modelling of the thermodynamic process taking place during the scavenge process in such engine. At assumed geometry of the engine, initial and boundary conditions the change of engine parameters such as pressure, temperature, density, heat exchange and volume are calculated on the base of zero-dimensional model as a function of rotation angle of the piston. Forming of the mixture during fuel injection process in compression process gives information about the air excess ratio. The presented model is applicable for different sort of fuels. This work is introduction to a broader analysis of the processes in spatial system. Application of hydrogen reduces of toxic components emission from such engine, but decreases also engine power.

PL

Silnik Wankla byl bardzo interesujący dla przemysłu samochodowego prawie czterdzieści lat temu ze względu na małe wymiary, kompaktowość, prostą konstrukcję, równomierność pracy silnika i brak drgań wywołanych siłami bezwładności. Wadą tego silnika była duża toksyczność emitowanych spalin, szczególnie węglowodorów i tlenków azotu oraz duże zużycie paliwa. Te niedoskonałości silnika mogą być wyeliminowane dzięki zastosowaniu bezpośredniego wtrysku paliwa o dużej liczbie oktanowej lub wodoru. Głównym celem pracy jest modelowanie parametrów termodynamicznych procesów zachodzących w czasie przepłukania w tym silniku. Przy założonych parametrach geometrycznych silnika, warunkach brzegowych i początkowych obliczono zmiany parametrów takich, jak: ciśnienie, temperatura, gęstość, prędkości wlotu i wylotu za pomocą własnego programu komputerowego opartego na modelu 0-D w funkcji kąta obrotu wału korbowego. Tworzenie mieszanki podczas wtrysku paliwa daje informację o współczynniku nadmiaru powietrza. Zaprezentowany model obliczeniowy jest dostosowany do różnego rodzaju paliwa. Praca jest wstępem do szerszej analizy procesów przestrzennych w komorze spalania. Zastosowanie wodoru zmniejsza emisję szkodliwych składników spalin, lecz zmniejsza również moc silnika.

11

Ignition of CNG mixtures in spark ignition engines

100%

Mitianiec W.

Journal of KONES

|

2012

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tom Vol. 19, No. 3

297-304

EN

Nowadays in automotive industry, the applying of gaseous fuels and particularly compressed natural gas both in SI and CI engines is more frequent. Application of CNG in the spark ignition internal combustion engines is more real than never before. The paper describes a problem of ignition of CNG mixtures formed in SI engines with direct injection, which requires higher energy supplied by the ignition systems. The main topic of this problem was determined on the basis of the work in NICE project. The paper presents the mathematical model of ignition of CNG mixture and results of calculations. One presents dependencies between different thermal parameters on requiring electric energy. The paper shows also results of experimental results carried out in the caloric chamber done in Cracow University of Technology and chosen results of testing different ignition systems. It was modelled ignition process of the air-methane mixture in the part of combustion chamber with real spark plug. Simulation process was carried out for simple kinetic chemical reaction at initial pressure 20 bar and temperature 900 K. The paper presents calculation CFD model with high density tetrahedral mesh. Transient modelling enables obtaining of the flame spreading in the considered chamber by presenting temperature distribution and kinetic reaction rate for four times. Mass fractions of methane, carbon dioxide and water vapours are shown in dependence on time in the diagrams. The simple combustion model indicated high temperature above 3500 K in the ignition kernel at the beginning of sparking.

12

Aspects of combustion process in a high pressure direct fuel injection two-stroke engine

100%

Mitianiec W.

Journal of KONES

|

2011

|

tom Vol. 18, No. 4

289-298

EN

The paper presents combustion process in loop scavenging two-stroke engine with high pressure direct injection of gasoline. A new method of determination of heat release rate on the base of experimental test in a two-stroke engine with direct gasoline injection is also presented. The target of the work was achieving of information about implementation of approximated Viebe function in mathematical models and simulation computer programs of a combustion process in spark ignition two-stroke engine with direct fuel injection due to the lack of such data in the literature. The paper show propagation of the flame in the combustion chamber depending on charge flow after scavenge process. The paper presents several examples of heat release and approximate function, for which variable coefficients of Viebe function were determined for certain rotational speeds at wide opening throttle. Pressure measurements were carried out on the engine Robin EC12 wit capacity 115 cm3. Determination of heat release and burned fuel rate was calculated by means of own computer program. The paper also presents the method of determination of variable specific heat coefficients in the function of crankshaft rotation, which are also used in modelling of the engine processes.

13

Heat recovery system in a future diesel particle filter

100%

Mitianiec W.

Journal of KONES

|

2009

|

tom Vol. 16, No. 4

333-342

EN

The main problem in conventional diesel engines and HCCI diesel is reduction of solid particles emitted to atmosphere. applying of particle filters requires special methods for their regeneration after some period of the engine work in a result of closing of substrate pores by soot. These methods require additional energy for combustion of soot (additional fuel or electric energy). The new method takes into account a self-regeneration of diesel particle filter by use of special heat recovery system. The paper shows an example of DPF self-regeneration. the exhaust temperature behind the turbine and catalytic converter is very low and particularly for HCCI engine the emission of particles is low in comparison to conventional diesel engines. for that case an additional energy is required for increase of gas temperature before DPF. the preliminary studies show a possibility of using the special design of DPF with heat recovery system. the paper shows the simulation results of such system and possibility of increasing the heat recovery ratio by change of geometry of DPF. the gas heat exchange formulas between dpf and the heat exchange module are partly included in the paper. the preliminary results of calculations shows the possibility of increase of exhaust gases in front of DPF about 20%, which enables a continuous regeneration of DPF. the work is carried out as part of the european project ipsy.

14

Ignition and combustion process in high charged SI engines with direct injection of CNG

100%

Mitianiec W.

Journal of KONES

|

2005

|

tom Vol. 12, No. 1-2

247-256

EN

The paper concerns the direct injection in SI internal combustion engines by compressed natural gas in order to decrease the global CO2. The increase of the working parameters of the spark ignition engines in comparison to the diesel engines would be done by applying a high charge pressure and with direct injection of CNG for two modes with the homogenous charge and stratified charge. Decreasing of NOx emission is possible by fuelling the engine by lean mixtures ( lambda= 1.2 - 1.6). Ignition of the mixture at high compression pressure above 40 bars requires applying of a strictly defined dose of gas fuel. Sparking of the high compressed mixture can be done only by high voltage ignition system. The paper describes the total problems of injection, ignition and combustion CNG in high compressed spark ignition engines with simulation results in one-cylinder fourstroke SI engine. There are also compared the test and calculation results in the caloric chamber. The paper gives dependences of compression ratio and air-fuel ratio for lean burning of CNG.

15

Perspectives of applying of water-coal emulsion in heavy duty stationary diesel engines

100%

Mitianiec W.

Combustion Engines

|

2015

|

tom R. 54, nr 3

744--751

EN

Large deposits of coal and lignite in the world enable to utilize as fuel in different thermal machines, especially in internal combustion engines. A carbon powder containing small molecules about 5–10 micrometers dissolved in water is good fuel for applying in large capacity engines in electrical plants. Aqueous emulsion of coal has possibility of good cooling of injectors cooling and has also good lubricity. The paper gives necessary information about obtaining of water-coal emulsion, its physical properties and technical realization of fuelling system. Initial experimental tests indicate a higher thermal efficiency of engine fuelled by water coal emulsion than engine fuelled by diesel oil and also gas turbine driven by gas from coal gasification technology. The in-creased emission of CO2 can be reduced in the plants simply by chemical reduction. The paper explains thermo-chemical processes taking place in the engines during combustion process. The work parameters results obtained from calculations were compared with those obtained from CI engine fuelled by diesel oil. The paper is a certain challenge for finding a new fuel sources as a competition for crude oil and allows to get acquainted with new engine fuelling technology.

PL

Duże pokłady węgla kamiennego i brunatnego na świecie umożliwiają wykorzystanie jako paliwa w rozlicznych maszynach cieplnych, szczególnie w tłokowych silnikach spalinowych. Sproszkowany węgiel zawierający małe drobiny około 5–10 mikrometrów rozpuszczony w wodzie jest dobrym paliwem do zastosowania w silnikach Diesla o dużej pojemności w elektrowniach. Wodny roztwór węgla umożliwia dobre chłodzenie wtryskiwacza oraz wykazuje również dobrą smarność. Artykuł podaje niezbędne informacje o otrzymywaniu emulsji węglowo-wodnej, podaje jej właściwości fizyczne oraz techniczną realizację takiego systemu zasilania. Wstępne badania doświadczalne wykazały większą sprawność cieplną silników zasilanych taką emulsją niż silniki zasilane olejem napędowym oraz turbin gazowych zasilanych produktami zgazowywania węgla. Większa emisja CO2 może być zredukowana w elektrowniach przez chemiczną redukcję albo sekwestrację. Artykuł wyjaśnia procesy termochemiczne występujące w procesie spalania takich silników. Parametry robocze silnika zasilanego emulsją węglowo-wodną otrzymane z symulacji zostały porównane z parametrami silnika zasilanego olejem napędowym. Artykuł jest próbą znalezienia nowego źródła paliwa jako konkurenta w stosunku do ropy naftowej i pozwala zaznajomić się nową techniką zasilania silnika spalinowego.

16

Modelling of the mixture formation in a small SI two-stroke engine with side and top direct injection

100%

Mitianiec W.

Journal of KONES

|

1999

|

tom Vol. 6, No. 1-2

112-126

EN

In a small two-stroke engine various injection systems can be applied. In the paper the influence of injector location on the mixture formation is considered. Two locations of injector were investigated: side location - opposite to the exhaust port and top location near the spark plug. Modelling of physics process during injection was done with assumption of the same geometrical dimensions and injection parameters in both two systems. The hemisphere combustion chamber causes additional motion of gas and fuel before ignition. Forming of vapour phase in the cylinder from the beginning of injection to ignition depends on the gas flow and turbulence in combustion chamber after scavenge process. For calculation a finite elements method included in PHOENICS programs was used. Formation velocity of fuel gas phase is different and changes during crankshaft rotation for two considered systems. In the paper the following variation for various piston position were shown: distribution of liquid and gas phase of fuel, temperature, velocity vectors of charge and vapour mass ratio. Application of both systems depends on design requirements and using of commercial automotive injectors. Modelling of mixture formation during injection takes effect on the prediction of the injection time and its duration for different working loads and speeds. The combustion process have not been analysed.

17

Proposal of a piston engine with close thermal cycle of working medium

100%

Mitianiec W.

Journal of KONES

|

2013

|

tom Vol. 20, No. 1

209--217

EN

Ecological aspects and utilization of biomass as a fuel leads to applying of a closed work cycle in the piston engine. It forces usually to delivering of heat to working medium through a heat exchanger. The heat may get from any type of fuel in an external combustion chamber, which allows on precisely control of combustion process. The paper describes a new conception of the engine operating in two-stroke cycle with working medium being in the close system, the best with the perfect gas as argon or helium. The delivering process of working medium with high temperature from the heat exchanger takes place through the inlet valve during a few dozen degrees of CA rotation in piston position at TDC. Expansion stroke takes place until outlet valve opens shortly BBDC. The outlet period from the cylinder follows almost at constant pressure and at low temperature to an adiabatic chamber, from where the working medium is compressed by an adiabatic compressor to pressure near pressure being in the heat exchanger. The engine works in two-stroke cycle and enables to get low temperature and pressure as early as BDC through a long time of opening of the outlet valve. The paper presents the ideological scheme of the engine system and theoretical thermal cycle. On this basis one presents the theoretical description of the individual thermodynamic processes with determination of thermal parameters of the characteristic points of the cycle. This article determines also the thermal efficiency of such closed cycle. The presented engine may have a practical applying as a stationary engine in energetic systems, where as fuel may be biomass, which globally influences on decreasing of CO2 and NOx by temperature control of the combustion process

18

Wpływ bezpośredniego wtrysku paliwa na emisję spalin w dwusuwowym silniku spalinowym ZI

100%

Mitianiec W.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

|

2012

|

tom z. 1/87

49--58

PL

W pracy przedstawiono wyniki badań doświadczalne emisji wybranych składników spalin uzyskane na eksperymentalnym silniku dwusuwowym ZI z bezpośrednim wtryskiem benzyny. Uzyskano ponad 10-krotne zmniejszenie udziału objętościowego węglowodorów oraz znaczne zmniejszenie udziału objętościowego tlenku węgla w spalinach w porównaniu do standardowego silnika gaźnikowego. W pracy przedstawiono charakterystyki obciążeniowe emisji węglowodorów, tlenku węgla, tlenków azotu oraz jednostkowego zużycia paliwa oraz charakterystyki prędkościowe tych emisji dla silnika gaźnikowego i badawczego Zastosowanie bezpośredniego wtrysku paliwa pozwoliło również na zmniejszenie jednostkowego zużycia paliwa o ponad 30 procent.

EN

The paper presents experimental results of exhaust gas emission of chosen components obtained on modified SI two-stroke engine with direct gasoline injection. The experimental research indicated above 10-times decreasing of volumetric ratio of hydrocarbons and a considerable decrease of carbon monoxide emission in comparison to the standard carburetted engine. The work presents load characteristics of emission of hydrocarbons, carbon monoxide, nitrogen oxides and specific fuel consumption and speed characteristics those emissions for the carburetted engine and experimental engine. Application of direct fuel injection enables also decreasing of specific fuel consumption above 30 percent.

19

Self-regeneration method of diesel particulate filter

100%

Mitianiec W.

Journal of KONES

|

2010

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tom Vol. 17, No. 1

273-281

EN

Compression ignition engines have no possibility for self-regeneration of DPF and regeneration requires additional energy for soot combustion (additional fuel or electric energy) after some period of the engine work as a result of closing of substrate pores by soot. The innovation method takes into account a self-regeneration of diesel particle filter by use of special heat recovery system. The paper shows one of possible design of DPF self-regeneration. The exhaust temperature behind the turbine and catalytic converter is very low and for an increasing of gas temperature before DPF, the heat from soot combustion can be used. The preliminary studies show a possibility of using the special design of DPF with heat recovery system. The paper presents results obtained from simulations based on one-dimensional model of such system and analysis of increasing the heat recovery ratio by change of geometry of DPF. The gas heat exchange formulas between DPF and the heat exchange model are partly included in the paper. The preliminary results of calculations show the possibility of increase of exhaust gases in front of DPF about 20%, which enables a continuous regeneration of DPF. Heat recovery ratio is depends on soot combustion rate on the wall of DPF monolith. The method enables to recover some part of energy which is lost in the conventional DPF. The paper is a part of further work in European project FP6 IPSY.

20

Mixture formation at spray guided direct injection in SI two-stroke engine

63%

Mitianiec W. , Forma M.

Czasopismo Techniczne. Mechanika

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2008

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tom R. 105, z. 7-M

115-127

EN

In the paper the top direct injection on the mixture formation is considered. Modelling of physics process during injection was carried out with assumption of the exact future experimental set-up. The hemisphere combustion chamber causes additional motion of gas and fuel before ignition. A difference approximation of differential equations of the injection and combustion was used for solving the problem by KIVA program. Velocity of gas influences on the distribution of liquid and vapour phases of injected fuel. In the paper: distribution of gaseous phase of fuel, gas temperature, vectors of charge velocity and vapour mass ratio for top and side fuel injection systems were shown.

PL

W artykule rozważano proces bezpośredniego wtrysku paliwa. Modelownie procesu fizycznego wtrysku paliwa zostało przeprowadzone przy założeniu przyszłego badawczego silnika. Półkulista komora spalania powoduje dodatkowy ruch gazu i paliwa przed zapłonem. Do rozwiązania tego problemu przeprowadzono aproksymację różnicową równań różniczkowych procesu wtrysku i spalania za pomocą programu KIVA. Prędkość gazu wpływa na rozprzestrzenianie się fazy ciekłej i parowej wtryskiwanego paliwa. W artykule pokazano rozkład par paliwa, temperaturę gazu, wektory prędkości ładunku i udział masowy par paliwa przy głowicowym i bocznym wtrysku paliwa.