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1

An example of adoption of the model-based design (MBD) methodology in the development process of an LPG fuelling system

Sidorowicz Maciej

Combustion Engines

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2023

|

R. 62, nr 3

104--108

EN

The research aims to recognize the potential of adopting the model-based design methodology to the development process of an LPG (liquefied petroleum gas) fuelling system. Changing regulations often force the modern development of internal combustion engines (Euro 7, CO2 reduction measures, etc.). With the definitive ban on new registrations of vehicles powered by internal combustion engines in Europe (planned for 2035), there is still ongoing development of the adaptation of the fuelling system to LPG. There is still market potential in adapting new internal combustion engines, usually equipped with direct injection systems, to reduce customers’ cost of ownership of a vehicle. As the engineering process should be accelerated in the face of the variety of direct injection systems offered by OEMs (original equipment manufacturers), the model-based design methodology is proposed to make the development more effective. The article presents the SWOT analysis of this approach in the engineering process and the potential of the method in an LPG system development is concluded.

2

The impact of alcohol admixture with gasoline on carbon build-up and fuel injectors performance

Stępień Zbigniew, Pielecha Ireneusz, Cieslik Wojciech, Szwajca Filip

Eksploatacja i Niezawodność

|

2022

|

Vol. 24, no. 2

226--236

EN

The operating conditions of injectors in spark ignition engines with direct fuel injection make them susceptible to coking, which leads to a reduced quality of fuel atomization. This can be observed by a drop in performance and an increase in exhaust emissions, especially particulate matter. One effective method of reducing injector coking is by using detergentdispersing gasoline additives. The article describes the effect of using an admixture with a varied alcohol content on the quantitative and qualitative fuel atomization indicators. The research consisted of a 48-hour engine test, done in accordance with the CEC F-113-KC procedure (CEC-F-113 test). After each test cycle, the injectors underwent optical tests with the use of an isochoric chamber. The spray penetration and surface area were analyzed at a set of different fuel injection parameter values. The research performed resulted in determining the influence of each tested admixture on the change of injection time and on the geometric indicators of the fuel spray. The obtained characteristics of the engine in operation and conducted stationary tests enabled the operational evaluation of the impact an alcohol admixture with gasoline fuels had on key engine parameters.

3

Investigation of a new concept of hydrogen supply for a spark-ignition engine

Brzeżański Marek, Rodak Łukasz

Combustion Engines

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2019

|

R. 58, nr 3

140--143

EN

The article presents the results of conceptual and research works of an internal combustion engine adapted for hydrogen supply. The engine was equipped with a direct injection of hydrogen into the combustion chamber, allowing the control of the heat release rate. The developed concept of the power supply system and the fuel injection strategy were presented. Initial results of bench tests were also presented.

4

Influence of the method of creating a hydrogen-air mixture on the emission of nitrogen oxides in a spark-ignition engine

Brzeżański Marek, Rodak Łukasz

Combustion Engines

|

2019

|

R. 58, nr 3

224--227

EN

The article presents an analysis of phenomena affecting the formation of nitrogen oxides during the combustion of a hydrogen-air mixture in a spark-ignition engine. Studies have been carried out to determine the strategy of creating and burning a hydrogen-air mixture that guarantees a low concentration of nitrogen oxides. This strategy limits the synthesis of nitrogen with atmospheric oxygen during engine operation.

5

Harmful exhaust components and particles mass and number emission during the actual drive of a passenger car in accordance with the RDE procedure

Sokolnicka Barbara, Fuć Paweł, Szymlet Natalia, Siedlecki Maciej, Grzeszczyk Rafał

Combustion Engines

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2019

|

R. 58, nr 3

198--202

EN

The article presents toxic exhaust components emission measurement results as well as solid particles mass and number. The test involved a direct gasoline injection engine, in which special attention should be paid to the particulates number emission. Small diameters of nanoparticles make them particularly dangerous to human health. Nowadays, vehicle engines are constantly improved and modernized as a result of the need to meet existing exhaust gas emission standards. One of the few ways to determine the actual content of toxic and harmful compounds in the exhaust gases is the RDE (Real Driving Emissions) procedure, the requirements of which apply from 2016 for new vehicles, and from 2019 will apply to all registered passenger cars. The RDE procedure does not replace the WLTP (World Light-Duty Vehicle Test Procedure), but complements it. The tests on the dynamometer are separated from external conditions such as traffic volume or congestion and are not a sufficient indicator of emissions in real traffic conditions.

6

A new fuel-injection mechatronic control method for direct-injection internal combustion engines

Tutaj J., Fijałkowski B.

Acta Mechanica et Automatica

|

2018

|

Vol. 12, no. 4

276--280

EN

In this paper, a novel fuel-injection mechatronic control method and system for direct injection (DI) internal combustion engines (ICE) is proposed. This method and system is based on the energy saving in a capacitance using DC-DC converter, giving a very fast ON state of the fuel injectors’ electro-magnetic fluidical valves without an application of the initial load current. A fuel-injection controller for the DI ICEs that provides a very short rising time of an electromagnet-winding current in an initial ON state of the fuel-injector’s electromagnetic fluidical valves, which improves a fuel-injection controller reliability and simplify its construction, is presented. Due to a number of advantages of afore -mentioned fuel-injection mechatronic control method and system, it may be utilised for the DI ICEs with fuel injectors dedicated to all types of liquid and/or gas fuels, for example, gasoline, diesel-oil, alkohol, LPG and NPG.

7

Optical tests as the basis for formulating mathematical models of the opening delay of CIDI injectors

Skowron M., Wisłocki K., Pielecha I.

Combustion Engines

|

2017

|

R. 56, nr 4

185--192

EN

The main objective of this research was an attempt to evaluate the delay times of the actual needle opening of the diesel injectors in relation to the time of triggering the current control signals opening the solenoid and piezoelectric high-pressure injectors of diesel engines. The conducted tests take into account the variability of fuel injection pressure and backpressure prevailing in the operational chamber of the engine. To determine accurately the time of actual injection start, the optical tests analysing the image of the injector tip were used. Such high resolution images were obtained by high-speed recording with a frequency of 250 kHz (Dt = 0.004 ms). Based on a comparison of the results obtained, it was found that the maximum delay time of fuel injection for a piezoelectric diesel injector is about 12% shorter than for a solenoid injector. Experimentally obtained results of the injection time delay were used as a basis to formulate mathematical models describing the delay of the real fuel injection in relation to the signal controlling the opening of the diesel injectors. These models take into account the dependence of the injector reaction from the injection pressure and the backpressure in the operational chamber of the engine. The correctness of the obtained models is confirmed by acceptable values of the determination coefficient (for solenoid injector – 0.6, for piezoelectric injector – above 0.8 – for correlation of injection delay and backpressure).

8

Numerical investigation into the effect of direct fuel injection on thermal stratification in HCCI engine

Gęca M., Hunicz J., Jaworski P.

Combustion Engines

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2017

|

R. 56, nr 2

137--140

EN

Despite the fact that HCCI engines are distinguished by mixture homogeneity, some degree of stratification always appears inside a combustion chamber. It is especially applied to residual effect engines utilizing negative valve overlap. Mixture stratification is a result of the imperfect mixing of fresh air with trapped residuals. Direct fuel injection introduces stratification as well, due to fuel vaporization. As a consequence, the temperature within the combustion chamber is uneven. Thermal stratification affects auto-ignition timing and combustion evolution in a high extent. The purpose of this study was to evaluate a degree of thermal stratification in HCCI engine utilizing negative valve overlap. Investigations were performed using three-dimensional CFD model of the combustion system, made by using AVL FIRE software. Simulations were realized for various timings of fuel injection into the cylinder. It was found that fuel injection timing had a significant effect on the thermal stratification and resulting auto-ignition timing.

9

Blends of ethanol, n-butanol and isobutanol with 5% oxygen in ordinary engines: effects on exhaust emissions over the Artemis cycle

Beranek V., Vojtisek-Lom M., Stolcpartova J., Mikuska P., Krumal K.

Prace Naukowe Instytutu Nafty i Gazu

|

2015

|

nr 204

186--198

EN

In the EU, alcohol fuels are used mostly in the form of ethanol, sold either as E85, or mixed in less than 10% concentrations into gasoline for the general fleet. This work examines the effects of extending the ethanol share to 15%. Additionally, considering the high hygroscopicity and corrosivity of ethanol, two isomers of butanol, n-butanol and isobutanol, were blended with gasoline at 25% by volume, all blends corresponding to approximately 5% oxygen by weight. These four fuels were examined in two typical spark ingition automobile engines, a Ford Focus car with a Euro 6 EcoBoost direct injection (DISI) engine, and a Skoda Fabia car with a Euro 5 multipoint injection (MPI) engine. Both cars were tested on chassis dynamometer using the Artemis driving cycle. There were no measurable effects on the emissions of hydrocarbon and carbon monoxide. The alcohol fuels increased the emissions of nitrogen oxides on the MPI engine. On the DISI engine over the Artemis cycle, the number of emitted solid particles and the emissions of elemental carbon and polyaromatic hydrocarbons were reduced relative to gasoline, by about one half for both butanol isomers, while ethanol did not yield observable effects. Particle emissions of the MPI engine were generally smaller. The results suggest that both n-butanol and isobutanol are viable fuels, which could be considered as an alternative to ethanol.

10

Wykorzystanie mikro czytnika diagnostycznego w badaniach eksperymentalnych jednostek napędowych na hamowni podwoziow

Szlachetka M., Siadkowska K., Czyż Z.

Logistyka

|

2015

|

nr 3

4722--4730, CD 1

PL

W artykule przedstawiono badania pojazdu z silnikiem o zapłonie samoczynnym na hamowni podwoziowej Celem badań była weryfikacja poprawności działania opracowanego systemu wtrysku gazu CNG do komory spalania. Badania przeprowadzono realizując na hamowni test jezdny ECE dla różnych wariantów składu paliwa. Zastąpiono kolejno 25, 50 i 60% oleju napędowego poprzez wtrysk bezpośredni gazu ziemnego. Obiektem badawczym był samochód dostawczy GAZ Gazelle wyposażony w silnik ANDORIA ADCR spełniający normę czystości spalin EURO-4. Podczas badań do rejestracji podstawowych parametrów pracy silnika wykorzystano bezprzewodowy mikroczytnik OBD Log firmy Texa montowany w złączu diagnostycznym pojazdu. W artykule przedstawiono przykładowe wyniki pomiarów wykonanych podczas realizacji testu jezdnego ECE.

EN

The paper presents the results of chassis dynamometer experiments on a vehicle with a diesel engine to verify the operation of our system to inject CNG into a combustion chamber. The experiments are based on chassis dynamometer ECE driving tests for varied fuel compositions, i.e. direct injection by natural gas is applied instead of 25, 50 and 60% of diesel fuel. The research object is the GAZ Gazelle van fitted with the ANDORIA ADCR engine that meets the Euro 4 standard. The basic operating parameters of the engine are recorded with the Texa wireless OBD Log micro diagnostic tool plugged directly into a vehicle's diagnostic socket. The paper presents the sample ECE driving test measurements.

11

Analiza porównawcza rozpylenia paliwa przez wybrane typy wtryskiwaczy paliw ciekłych

Skowron M., Pielecha I.

Logistyka

|

2015

|

nr 3

4439--4448, CD 1

PL

W artykule omówiono zagadnienie rozpylenia paliwa w układach bezpośredniego wtrysku zarówno dla silników ZS jak i ZI. Przeprowadzono analizę porównawczą wtryskiwaczy ze względu na ich budowę. Celem artykułu było wskazanie tendencji rozwoju konstrukcji wtryskiwaczy i idących za tym zmian dotyczących rozpylenia i zasięgu strugi. Do tego celu przygotowano przegląd literaturowy zagadnienia dotyczący najnowszych rozwiązań oraz uzupełniono go o badania własne rozpylenia paliwa. Prace te wykonano dla wybranych konstrukcji wtryskiwaczy, a zarejestrowane obrazy poddano obróbce w celu ekspozycji charakterystycznych cech strugi paliwa z wtryskiwacza przystosowanego do konkretnego systemu spalania.

EN

In this paper was discussed fuel spray issue in DI both for SI and CI engines. There was conducted comparative analysis of injectors in aspect of their construction. The main aim of article was to mention development trend in injection system construction and binding to them atomization improvement and relative stream range. To reach that aim literature review of issue was given and supplemented by own fuel atomization research. Those operations was performed for selected injector constructions and recorded images were treated image processing in aim to expose characteristic fuel stream attributes causing by adaptation for concrete combustion system.

12

Environmental emissions and efficiency of a direct injection diesel engine fueled with various fatty acid methyl esters

Sairam K., Gopinath A., Velraj R.

Environment Protection Engineering

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2015

|

Vol. 41, nr 1

125--135

EN

Environmental emissions and efficiency of a direct injection diesel engine fueled with fatty acid methyl esters (FAMEs) have been experimentally investigated and compared with petro-diesel. Rubber seed oil methyl ester, cotton seed oil methyl ester, neem oil methyl ester, and mahua oil methyl ester were used as fuels. The brake specific fuel consumption, brake thermal efficiency, and exhaust gas temperature, nitrogen oxides, carbon monoxide, hydrocarbons, and smoke emissions were investigated. Mahua oil methyl ester exhibits higher brake thermal efficiency compared to other FAMEs. The NOx was found to be higher, while CO, HC, and smoke emissions of rubber seed oil methyl ester were lower than the other fuels at all loads.

13

Stanowiskowe badania wtryskiwacza bezpośredniego wtrysku CNG

Sochaczewski R., Wendeker M., Barański G., Majczak A.

Combustion Engines

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2015

|

R. 54, nr 3

442--448

PL

Artykuł zawiera wyniki badań stanowiskowych wtryskiwacza sprężonego gazu ziemnego (CNG). Badania wykonano na stanowisku badawczym w warunkach ustalonych. W trakcie badań mierzono napięcie i natężenie prądu w obwodzie cewki elektromagnetycznej, ciśnienie gazu za wtryskiwaczem oraz jego wydatek. Na podstawie otrzymanych wartości wyznaczono parametry pracy wtryskiwacza w zależności od wzniosu iglicy i ciśnienia wtrysku. Badania pozwoliły zdefiniować różnice między teoretycznym (elektrycznym) a rzeczywistym czasem wtrysku. W efekcie wyznaczono opóźnienia otwierania i zamykania wtryskiwacza oraz niepowtarzalności tych wartości w kolejnych cyklach wtrysku gazu. Wykazano większy wpływ wzniosu iglicy w porównaniu do ciśnienia wtrysku na badane parametry pracy wtryskiwacza. Wraz ze zwiększaniem ciśnienia wtrysku wzrasta siła domykając zawór wtryskowy co niekorzystnie wpływa na niepowtarzalność pracy wtryskiwacza. W artykule przedstawiono również koncepcję wtryskiwacza przeznaczonego do bezpośredniego wtrysku gazu CNG do komory spalania silnika dwupaliwowego. Opracowana konstrukcja wtryskiwacza zapewni zastąpienie do 80% oleju napędowego w silniku dwupaliwowym o mocy maksymalnej 85 kW. Minimalne ciśnienie wtrysku wynosi 1,4 MPa. Jednocześnie wyznaczono charakterystykę wtryskiwacza dla różnych wzniosów iglicy i nieliniowe punkty pracy wtryskiwacza.

EN

This paper presents the bench research results on a CNG injector at steady state. The quantities measured included voltage and current in a solenoid, pressure of gas behind an injector and injector’s flow rate. Accordingly, injector’s operation parameters were determined according to needle’s lift and injection pressure. The discrepancies between the theoretical (electric) and actual time of injection were defined to specify injector’s opening and closing lag times and the uniqueness of these values in successive cycles of gas injection. It has been demonstrated that needle’s lift has got a stronger impact on injector’s operating parameters than injection pressure. With increasing injection pressure, the force increases and closes an injection valve, which adversely affects uniqueness of injector’s operation. The paper also describes the concept of an injector dedicated to direct CNG injection into a combustion chamber in a dual-fuel engine. The injector’s design enables us to replace 80% of diesel fuel in a dual-fuel engine with a maximum power of 85 kW. Minimum injection pressure is 1,4 MPa then. Simultaneously, injector’s characteristics for varied needle’s lifts and injector’s nonlinear operating points were developed.

14

Numerical simulations of dual fuel combustion in a heavy duty compression ignition engine

Kapusta Ł. J., Teodorczyk A.

Combustion Engines

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2015

|

R. 54, nr 4

47--56

EN

In this study dual fuel direct injection was studied in terms of utilizing in compression ignition engines gaseous fuels with high octane number which are stored in liquid form, specifically liquid propane. Due to the fact that propane is not as much knock-resistant as natural gas, instead of conventional dual fuel system a system based on simultaneous direct injection of two fuel was selected as the most promissing one. Dual fuel operation was compared with pure diesel operation. The performed simulations showed huge potential of dual fuel system for burning light hydrocarbons in heavy duty compression ignition engines. However, further secondary fuel injection system optimization is required in order to improve atomization and lower the emissions.

PL

W niniejszej pracy przeanalizowano dwupaliwowy układ zasilania oparty na bezpośrednim wtrysku dwóch paliw w kontekście wykorzystania gazowych paliw o dużej liczbie oktanowej, mianowicie propanu, w silnikach o zapłonie samoczynnym. Z uwagi na to, iż propan nie jest tak odporny na spalanie stukowe jak metan, zamiast konwencjonalnego układu dwupaliwowego łączącego wtrysk bezpośredni i pośredni zdecydowano się na zastosowanie koncepcji zasilania opartej na bezpośrednim wtrysku dwóch paliw. Praca silnika w trybie dwupaliwowym została porównana z pracą silnika wyłącznie na oleju napędowym. Przeprowadzone symulacje pokazały duży potencjał układów dwupaliwowych w kontekście wykorzystania lekkich węglowodorów w silnikach o zapłonie samoczynnym dużej mocy. Jednak, dalsza optymalizacja układu paliwowego jest niezbędna, aby poprawić proces rozpylenia paliwa i obniżyć emisję.

15

Analiza wytrzymałościowa wtryskiwacza CNG do systemu bezpośredniego zasilania silnika Diesla

Magryta P., Wendeker M., Sochaczewski R., Majczak A.

Combustion Engines

|

2015

|

R. 54, nr 3

425--431

PL

W artykule przedstawiono wyniki symulacyjnych badań wytrzymałościowych innowacyjnej konstrukcji wtryskiwacza CNG do bezpośredniego zasilania silnika Diesla. Wtryskiwacz został opracowany do zastosowania w silniku Andoria ADCR. Badania te wykonano w oparciu o Metodę Elementów Skończonych z wykorzystaniem oprogramowania Abaqus. Opracowany model geometryczny odzwierciedlał rzeczywistą budowę wtryskiwacza. Przeprowadzone badania symulacyjne miały na celu określenie miejsc podatnych na wystąpienie spiętrzeń naprężeń elementów wtryskiwacza pracujących w warunkach odpowiadających warunkom pracy w komorze spalania silnika Diesla. Celem odzwierciedlenie tych warunków w modelu uwzględniono wpływ siły pochodzącej od sprężyny wtryskiwacza oraz siły gazowej pochodzącej od ciśnienia gazów w cylindrze. Wpływ siły pochodzącej od ciśnienia w komorze spalania został wprowadzony do modelu na podstawie przebiegu wartości ciśnienia gazów w funkcji kąta obrotu wału korbowego z uprzednio prowadzonych obliczeń modelowych silnika w oprogramowaniu AVL Boost. Badania modelowe przeprowadzono dla warunków pełnego obciążenia silnika, dla jednego cyklu roboczego. Czas symulacji odpowiadał dwóm pełnym obrotom wału korbowego silnika, co w przeliczaniu dla prędkości obrotowej silnika 3500 obr/min odpowiadało czasowi symulacji równemu 0,03428 s. Na podstawie przeprowadzonych badań opracowano zoptymalizowaną konstrukcję wtryskiwacza, który wykorzystany został do przeprowadzenia badań stanowiskowych i hamowanianych systemu bezpośredniego wtrysku sprężonego gazu ziemnego do silnika Diesla.

EN

The article presents the results of strength simulation studies of innovative design of CNG injector for direct supply of the Diesel engine. The injector has been developed for use in Andoria ADCR engine. These studies were performed based on the Finite Element Method using Abaqus software. The geometric model reflects the actual structure of the injector. The conducted simulation studies aimed at determining the locations prone to the occurrence of stress concentrations in injector elements working in conditions equivalent to those in the combustion chamber of the Diesel engine. The objectives of these conditions are reflected in the model, that takes into account the influence of the spring force from the injector and the gas force from gas pressure in the cylinder. The influence of the gas force from the pressure in the combustion chamber was introduced into the model on the basis of the course of the gas pressure as a function of crank angle degree with a predetermined engine model calculations carried out in AVL Boost software. Simulation studies were carried out for engine full load conditions, for one combustion cycle. Simulation time corresponded to two full revolutions of the engine crankshaft, which in the conversion of the engine speed of 3500 rpm corresponds to the simulation time equal to 0.03428 s. On the basis of the simulation studies an optimized design of the injector, which was used for real bench tests of direct injection system supply of compressed natural gas into Diesel engine.

16

Badania symulacyjne obciążeń tłoków silników spalinowych o zapłonie samoczynnym z wtryskiem bezpośrednim

Kordos P., Sarnowski C., Wrona R.

Logistyka

|

2014

|

nr 3

3075--3082

PL

Warunki pracy tłoka w cylindrze są bardzo niekorzystne, ze względu na wysokie ciśnienie, temperaturę oraz prędkości i przyspieszenia. Są to jedne z najbardziej obciążonych mechanicznie i cieplnie elementów silnika spalinowego. Stawiane są im wysokie wymagania dotyczące stabilności wymiarowej, wytrzymałości i trwałości. Konstrukcjom wykonanym z klasycznych materiałów, coraz trudniej jest sprostać tym wymaganiom. Obszarem szczególnie narażonym na bardzo duże obciążenia cieplne w tym znaczne gradienty temperatury związane cyklicznością procesu roboczego jest korona tłoka. Wysokie temperatury pogarszają właściwości mechaniczne materiału, z którego wykonany jest tłok, a gradienty temperatur poszczególnych elementów lub obszarów tłoka (zwłaszcza w dużych silnikach) powodują dodatkowo powstawanie wewnętrznych naprężeń termicznych. W referacie przedstawiono wyniki badań symulacyjnych tłoków do silników o zapłonie samoczynnym z wtryskiem bezpośrednim różnych generacji. Badania miały na celu określenie wpływu konstrukcji tłoka na poziom obciążenia cieplnego. Badania numeryczne tłoka przeprowadzone zostały metodą elementów skończonych. Obciążenie tłoka zdefiniowane zostało poprzez zadanie warunków brzegowych wymiany ciepła oraz średnie ciśnienie użyteczne odpowiadające maksymalnemu obciążeniu silnika. Analizie poddawano temperatury poszczególnych obszarów a także odkształcenia i naprężenia wynikające z obciążenia cieplnego i mechanicznego.

EN

The engine piston working condition are very disadvantageous. Pistons belong to the most mechanically and thermally loaded components of the internal combustion engines and at the same time they have to fulfill very demanding requirements in terms of dimensional stability, strength and durability. For pistons made of classic materials it is increasingly difficult to meet these requirements. The area of piston crown is particularly under hazard of very high thermal loads and temperature gradients related to the cyclic variations of the engine working process. High temperature impair mechanical properties of engine piston material. High temperature gradient of piston elements or regions (especially in high load engines) bring to arise internal thermal stresses. The paper presents results of simulational calculations of the direct injection diesel engines different generations piston models. Research was aimed at determination of the influence of the construction (shape of the piston, material, manufacture technology) on the level of piston’s thermal load. Numerical analysis of the piston was made using finite elements method. Thermal load of the piston was defined by giving boundary conditions of the heat exchange and mean effective pressure corresponding to the maximum engine load. Paper presents analysis temperatures, deformation, stresses different pistons areas as result of thermal and mechanical load.

17

Development of a two stroke direct injection jet ignition compressed natural gas engine

Boretti A., Jiang S.

Journal of Power Technologies

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2014

|

Vol. 94, nr 3

145–-152

EN

A traditional two stroke engine with crankcase scavenging also adopting an exhaust reed valve and lamellar intake is modified to accommodate a high pressure Compressed Natural Gas (CNG) direct injector and has the traditional spark plug replaced by a jet ignition device of the same thread. The jet ignition device is a pre-chamber accommodating a Gasoline Direct Injection (GDI) injector operated with CNG and an 8 mm racing spark plug. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices. The CNG is injected after the exhaust post closes. The GDI injector operated with CNG introduces a slightly rich amount of fuel in the pre-chamber. The spark plug discharge initiates the pre-chamber combustion that then propagates to the main chamber though multiple jets of high energy partially burned hot combustion products that quickly ignite the main chamber mixtures. The Computer Aided Design (CAD) model of the engine including the jet ignition device is discussed in detail. The Computer Aided Engineering (CAE) model of the engine is shown to produce efficiencies well in excess of 35% in the area of best operation. The load is controlled by fine tuning the injection and ignition events and increasing the overall air-fuel ratio. The solution offers an opportunity to produce an efficient alternative to four stroke engines with improved power density, running on alternative fuel having larger availability and better combustion properties and reduced pollution than traditional diesel and gasoline fuels.

18

CFD model of the CNG direct injection engine

Czyż Z., Pietrykowski K.

Advances in Science and Technology. Research Journal

|

2014

|

Vol. 8, nr 23

45--52

EN

The paper presents CFD analysis of fuel flow in the CNG injector. The issues such a pressure drop along an injector channel, mass flow through the key sections of the injector geometry, flow rates, the impact of the needle shape on the deflection of the sprayed gas cone and the impact of the wall head are analyzed in the article. The simulation was made in the transient states conditions for full injection process, including the opening and closing of the injector. An injection time of 6 ms, velocity of 0.33 mm/ms and a lift of 0.5 mm were selected for opening and closing of injector based on experimental test. The simulation shows that the volume inside the injector is a kind of fuel accumulator, and the opening process of the needle influence the flow parameters in an inlet cross-section after a certain time, depending on a channel cross section. The calculations allowed to select the ratio of an injector duct cross sectional area to the aperture area of the injection capable of the reducing pressure loss. The unusual location of the injector in the socket of a glow plug in the Andoria ADCR engine makes a stream be impaired by a part of the head. This research result would be useful in developing an injector construction which will be used for an investigation of CNG addition into diesel engine.

19

A LES numerical approach for investigating the cycle-to-cycle combustion pressure variability in a direct injection gasoline engine

Teodorczyk A., Jaworski P., Priesching P., Tatschl R.

Combustion Engines

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2013

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R. 52, nr 3

794--799

EN

The Large Eddy Simulation method (LES) has become a powerful computational tool for the application to turbulent flows. It links the classical Reynolds Averaged Navier–Stokes (RANS) approach and Direct Numerical Simulation (DNS). This means that the large eddies are computed explicitly in a time-dependent simulation using the filtered Navier-Stokes equations. The LES resolves the large flow scales that depend directly on the geometry where the small scales are modelled by the subgrid-scale models. LES is expected to improve the description of the aerodynamic and combustion processes in Internal Combustion Engines. This paper addresses the topic of developing the combustion model GCM (Gradient Combustion model) for the Large Eddy Simulation (LES) method. Another part of this paper presents numerical investigations of cycle-to-cycle combustion pressure variability with comparison to experimental data. The Gradient Combustion model (GCM) based on the Turbulent Flame Speed Closure Model (TFSCM) is validated against the experimental data for a multi-cycle gasoline direct injection research engine (SCRE). It is shown that the introduced combustion model is stable and capable of proper representation of the experimental results which is one of the assets of the LES method.

PL

Metoda LES jest obecnie zaawansowanym narzędziem numerycznym do analizy przepływów turbulentnych. Metoda LES opiera się na połączeniu klasyczej metody uśredniania równań Naviera-Stokes (RANS) z bezpośrednią analizą numeryczną (DNS). Oznacza to, że duże struktury wirowe są rozwiązywane niejawnie poprzez filtrowanie równań Naviera-Stokesa. W metodzie LES oznacza to obliczanie przepływu dużej skali, który zależy od geometrii, podczas gdy przepływ w małej skali jest modelowany modelem podsiatkowym (ang. Sub-grid-scale models, SGS). Uważa się, że metoda LES pozwoli na poprawienie numerycznego opisu aerodynamiki i procesów spalania w silnikach tłokowych. Artykuł przedstawia wyniki prac rozwojowych nad modelem spalania w metodzie LES. Model GCM (model spalania oparty na metodzie gradientu) został zastosowany do obliczeń wielocyklicznych i ich weryfikacji z wynikami eksperymentalnymi. Wyniki eksperymentalne pozyskano z badań na jednocylindrowym silniku badawczym (SCRE) o wtrysku bezpośrednim. W pracy pokazano, że model spalania jest stabilny numerycznie oraz otrzymane wyniki są zgodne z wynikami eksperymentalnymi, co jest jedną z ważniejszych zalet metody LES.

20

Numerical Simulations of a Simultaneous Direct Injection of Liquid And Gaseous Fuels Into a Constant Volume Chamber

Kapusta Ł. J., Teodorczyk A.

Journal of Power Technologies

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2012

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Vol. 92, nr 1

12-19

EN

Numerical simulations of the dual fuelling process by simultaneous direct injection of liquid and gaseous fuels into a combustion chamber were performed. Diesel fuel and CH4 were injected into a constant volume vessel through separate nozzles. Injection started for both fuels at the same time. The presented simulations were done using the AVL Fire code - the CFD software dedicated to engine simulations. This work was the first step in a process of modeling the full engine cycle, including combustion. The aim of the study was to validate the spray model before applying it to more complex simulations. One major simplification was made to speed up the calculation process: instead of full chamber geometry only a 60 deg sector of the cylindrical chamber containing only two nozzles, one for gaseous fuel and one for liquid was investigated. The simulation results were compared with literature data [12]. The images from the numerical solution presenting spray droplets and CH4 concentration were compared with images made by the shadowgraph technique [12].