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1

An impact of tensor-based data compression methods on deep neural network accuracy

Grabek Jakub, Cyganek Bogusław

Annals of Computer Science and Information Systems

|

2021

|

Vol. 26

3--11

EN

The emergence of the deep neural architectures greatly influenced the contemporary big data revolution. How-ever, requirements on large datasets even increased a necessity for efficient data storage. The storage problem is present at all stages, from the dataset creation up to the training and prediction stages. However, compression algorithms can significantly deteriorate the quality of data and in effect the classification models. In this article, an in-depth analysis of the influence of the tensor-based lossy data compression on the performance of the various deep neural architectures is presented. We show that the Tucker and the Tensor Train decomposition methods, with properly selected parameters, allow for very high compression ratios, while conveying enough information in the decompressed data to achieve only a negligible or very small drop in the accuracy. The measurements were performed on the popular deep neural architectures: AlexNet, ResNet, VGG, and MNASNet. We show that further augmentation of the tensor decompositions with the ZFP floating-point compression algorithm allows for finding optimal parameters and even higher compressions ratios at the same recognition accuracy. Our experiments show data compressions of 94%-97% that result in less than 1% accuracy drop.

2

Simulation Research of the Influence of Compression Ratio on the Performance of an Aircraft Piston Diesel Engine

Grabowski Łukasz, Karpiński Paweł, Magryta Paweł

Advances in Science and Technology. Research Journal

|

2020

|

Vol. 14, no 3

175--181

EN

In recent years, the opposed-piston engines have become increasingly popular in the automotive and aerospace industries. Therefore, it is necessary to conduct the research on this type of drive. The paper presents the simulation research of a two-stroke opposed-piston diesel engine designed for propulsion of light aircrafts. The influence of the change of the compression ratio on the selected engine performance was investigated (indicated mean effective pressure, peak firing temperature and pressure, specific fuel consumption, power consumed by the compressor). The AVL BOOST software was used to perform the simulation tests. A zero-dimensional engine model equipped with a mechanical compressor was developed. On the basis of the created model, a series of calculations was performed for the assumed values of the compression ratio for four engine operating points: take-off power, maximum continuous power and cruising power at two different altitudes. The obtained results were subjected to a comparative analysis and the most important conclusions connected with the influence of the change in the compression ratio on the achieved performance were presented.

3

Analysis of charge exchange in a single-cylinder of spark ignition engine

Drabik Dawid, Mamala Jarosław, Prażnowski Krzysztof

Combustion Engines

|

2019

|

R. 58, nr 4

274--279

EN

The article presents the results of tests carried out on a single-cylinder of spark-ignition engine. The charge exchange process in the combustion chamber is very important to determine the possibility of improving the overall efficiency of the engine. Describes of impact modifications engine on open indicator diagrams. Open indicator diagrams show that the higher compression ratio is assumed, the higher the pressure in the system is. First parts of the research describes analysis of charge exchange on not working engine. Results of research presents different open indicators diagrams. Then the pressure results were obtained on the working engine. The possibilities of improving the overall efficiency of the engine by reducing the pumping loss, associated with the replacement of the air fuel mixture, were presented. The article describes the modification of a spark-ignition engine that affects the pressure change in the combustion chamber. The use of innovative methods of regulating the compression pressure gives a lot of positive effects.

4

New teoretical cycle for active combustion chamber engine

Głogowski Michal Piotr, Kubiak Przemysław, Šarić Željko, Barta Dalibor

Archiwum Motoryzacji

|

2019

|

Vol. 83, nr 1

23--42

EN

This paper presents calculations of the theoretical cycle of engines with an active combustion chamber depending on energy delivery and dissipation. In the case of ACC engines, a different calculation approach is required to account for the possibility of additional volume change, independent of the piston-crank system. The introduction presents a schematic diagram of volume change, accomplished by two independent piston-crank systems and an active combustion chamber, as proposed by the authors. Moreover, the diagram, which is the basis for analysis in this paper, illustrates characteristic points of the cycle. In existing theoretical cycles of combustion, this issue does not present any difficulties, since the solution is exact and based on known equations. In the case of theoretical ACC engines, however, the situation is different, since this engine can perform not only in typical cycles, but also in new ones. To explain the challenges of these new cycles, authors present a few of the most probable calculation variants, taking into account the new kinematic capabilities of ACC engines. Each comment justifying the choice of a certain calculation variant is illustrated with a theoretical cycle figure and closest approximation of induced pressure course of the ACC engine. At the same time, however, the authors show that this problem can have many interpretations. It has been concluded that the solution depends on the assumptions made about the active combustion chamber, namely its principle of operation.

5

The influence of the compression ratio error and the pressure error at the beginning of compression on the heat release characteristic calculated based on indicator diagram marine diesel engine

Witkowski K.

Journal of KONES

|

2018

|

Vol. 25, No. 1

457--463

EN

In the operational diagnostic of marine engines, the analysis of indicator diagrams is important. In addition to analysing changes in the values of indicated parameters, should be aimed to oriented broader analysis, including the determination on the basis of experimental indicator diagram of heat release characteristics during the combustion process. In the diagnostics of piston engines, including marine engines, special interest arouses to use single-zone model based on indicator diagrams as a source of information. There are calculated heat release characteristics: net heat release (Q) and intensity of heat release (q). The article discusses the impact problem the characteristics of heat release calculated based on experimental indicator diagram various errors – the compression ratio error and the pressure error at the beginning of compression. Based on the results of own research we analysed the impact on the characteristics of heat release the compression ratio error and the pressure error at the beginning of compression. The effect of the errors on the course of characteristics q and Q, to the typical marine medium speed engine Sulzer A25/30 and low speed engine Sulzer RTA 76 shown.

6

Computational investigation of compression ratio and bore diameter influence on engine performance and knock intensity

Gandyk M., Haller P., Jankowski A.

Journal of KONES

|

2018

|

Vol. 25, No. 2

129--134

EN

Processes of the combustion in combustion engines depend on cylinder bore and compression ratio. Compression ratio is a ratio of in-cylinder volume when piston is in bottom dead centre to volume when piston is in top dead centre. Theoretical engine efficiency is increasing together with compression ratio. However, in the real engine there are also other phenomena affecting the efficiency of the engine, which could results in lower performance of engine with higher compression ratio. This study presents knock intensity and performance gain in engine speed function of the 0D-1D engine model with different pistons set. Knock intensity is founded by implementing in combustion process knock sub-model based on Douaud and Eyzat induction time correlation using different pistons geometry. Examined engine model is air restricted Formula Student motorcycle engine. Mounted in intake system, air restrictor decreases knock intensity. Therefore, compression ratio could be increased. It was noticed that bigger bore diameter could reduce knock intensity. Researches realized that bigger bore size could cause performance drop at high rpm when flow is chocked. With changing of compression ratio, performance characteristic changes. Growing compression ratio decrease torque on low engine speed and increase on high engine speed. Further characteristic of the engine could be tuned by matching pistons with modified bore size and compression ratio.

7

Wpływ stopnia sprężania na sprawność ogólną silnika

Drabik D.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

|

2017

|

z. 108

23--26

EN

The article shows the processes that take place in an engine. The main terms connected with the compression ratio are explained. This document is a repetition of the problems connected with the functioning of the engine. The relationship between the compression ratio and the engine efficiency is described. Variables that influence the chart about thermodynamic cycle are described as well. This paper is a repetition of issues connected with functioning of the engine.

8

Evaluation of the effect of variable compression ratios performance on opposed piston 2-stroke engine

Alqahtani A., Wyszynski M. L., Mazuro P., Xu H.

Combustion Engines

|

2017

|

R. 56, nr 4

97--106

EN

Numerous skills involving the introduction of (OP) opposed piston engine have been developed in the recent past. Indeed, novel techniques can help to improve the performance of the engine. The aim of this paper is to model and simulate a simple single-cylinder two-stroke opposed-piston engine and minimise fuel consumption and heat loss, using the software programme AVL BOOST™. AVL BOOST is an engine modelling software, which analyses the performance of a modelled single cylinder two-stroke opposed-piston engine by changing desired parameters. In order to meet this aim, experimental results from a unique engine are used to make a comparison with the results obtained from AVL BOOST model. Six combinations of compression ratios (12, 13.5, 15, 16.5, 18 and 19.5) are analysed in this study with the engine speed running at 420 rpm and 1500 rpm. In addition to the compression ratios, the effect of stroke-to-bore (S/B) ratios on OP2S performance is investigated. Various values of S/B ratios, whilst maintaining a constant swept volume, port geometry and combustion timing, and their effect on fuel consumption and heat loss are analysed in this study. A comparison between the two engine speeds with increasing combinations of compression ratios, and the S/B ratios revealed minimal differences in peak pressure, peak temperature, IMEP, ISFC, indicated efficiency and total heat loss. Detailed analyses of these parameters are highlighted in discrete sections of this paper.

9

Sposoby realizacji zmiennego stopnia sprężania

Hennek K.

Autobusy : technika, eksploatacja, systemy transportowe

|

2017

|

R. 18, nr 6

723--728, CD

PL

W artykule omówione zostały rozwiązania konstrukcyjne silników spalinowych o spalaniu wewnętrznym, wyposażonych w układy zmiennego stopnia sprężania. Założeniem, przyświecającym ich twórcom, jest głównie obniżenie zużycia paliwa oraz emisji substancji szkodliwych i jest podyktowane coraz bardziej restrykcyjnymi przepisami dotyczącymi tejże emisji. Jednostki napędowe, w których zastosowano układy zmiennego stopnia sprężania, mogą mieć zastosowanie w pojazdach z klasycznym układem napędowym, a także w pojazdach hybrydowych. W końcowej części przedstawiono nowy zamysł układu realizującego zmiany stopnia sprężania w zależności od warunków obciążeniowych silnika.

EN

This paper presents descriptions of currently used variable compression ratio systems (VCR) of two –and four stroke SI and CI engines. VCR is used to improve efficiency and reduce emissions of harmful substances in exhaust gases. In a simplified manner, it describes the impact of the compression on the engine parameters. An own patented idea for achieving VCR was also presented.

10

Effective compression ratio of combustion engine as a way of increasing efficiency

Drabik D., Mamala J.

Journal of KONES

|

2016

|

Vol. 23, No. 3

93--99

EN

The article describes the processes that take place in an engine. The main terms connected with the compression ratio are explained. Moreover, the relationship between the compression ratio and the engine efficiency is discussed. This paper is a repetition of issues connected with functioning of the engine. In this article, variables that influence the chart are described, along with some examples of the way to increase engine efficiency. This article focuses on selected methods of improving efficiency of internal combustion engines. In order to fully understand processes taking place in the combustion chamber, it is necessary to create theoretical charts of thermal cycles and, then, to compare them with actual charts obtained as a result of measurements. The structure of contemporary engines is influenced by various factors, for example preservation of natural environment or limited fuel resources. These factors are crucial for mechanical engineering and engine design. Therefore, energy consumption and environmental impact of engines are taken into consideration when researching new ways and methods of enhancing engine efficiency. One of the main aims of the researchers and engineers is to reduce the emission of carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOx) in exhaust fumes. Improved engine efficiency, lowered fuel consumption and reduced emission of toxic substances are the main advantages of internal combustion engines characterized by variable compression ratio.

11

Technical and operating problems yielded from setting up the optimum value of geometric compression ratio in piston engines

Woś P., Jaworski A., Kuszewski H., Lejda K., Ustrzycki A.

Combustion Engines

|

2016

|

R. 55, nr 1

3--12

EN

The article discusses the problem of choosing the optimal compression ratio value in internal combustion engines at their design phase, according to today's development trends toward high economy and ecology of road transportation and the divers' expectations in vehicle use and performance. Because the variable compression ratio technology VCR is not yet developed well enough to be implemented into the mass production of engines in the near future, the choice of compression ratio value is always a serious task for constructors to find a compromise between the functional engine properties, operational characteristics, engine efficiency, the powertrain design complexity, and finally the exhaust emission level. Therefore, the paper examines the impact of the compression ratio on the combustion engine parameters mentioned above and presents some innovative designs, where the settings of the compression ratio value beyond the conventional range is connected with using additional solutions in design structure and control systems, with modifications corresponding to the working process in these engines.

PL

W artykule omówiono problem wyboru optymalnej wartości stopnia sprężania przy konstruowaniu silników spalinowych, zgodnie z trendami rozwojowymi w zakresie spełnienia wskaźników ekonomiki i ekologii transportu drogowego oraz ze współczesnymi oczekiwaniami użytkowników pojazdów w zakresie ich osiągów i eksploatacji. Ponieważ technologia zmiennego stopnia sprężania VCR (ang. Variable Compression Ratio) nie jest jeszcze na tyle zaawansowana, aby można było oczekiwać w najbliższym czasie jej wdrożenia do produkcji seryjnej, wybór wartości stopnia sprężania jest dla konstruktorów zawsze zadaniem znalezienia kompromisu pomiędzy założonymi parametrami użytkowymi, cechami eksploatacyjnymi, sprawnością silnika, złożonością konstrukcji i poziomem emisji szkodliwych składników spalin. W artykule przedstawiono zatem przeanalizowany wpływ wartości stopnia sprężania na wymienione wyżej parametry silników spalinowych oraz podano przykłady innowacyjnych konstrukcji, w których ustalenie wartości stopnia sprężania poza konwencjonalnym zakresem uwarunkowane jest zastosowaniem dodatkowych rozwiązań konstrukcyjnych i systemów sterujących, odpowiednio modyfikujących przebieg procesu roboczego w tych silnikach.

12

Rozwiązania konstrukcyjne silników o zmiennym stopniu sprężania

Malewicz K., Ligus G., Wasilewski M.

Logistyka

|

2015

|

nr 4

4715--4723, CD2

PL

W artykule opisane zostały zagadnienia poprawy sprawności ogólnej spalinowego silnika z zapłonem iskrowym poprzez zastosowanie podwyższonego stopnia sprężania. Autorzy opisali znane możliwości konstrukcyjne w zakresie umożliwiającym ruch głowicy cylindrowej, zastosowania tłoków dwuelementowych, mimośrodowego łożyskowania wału korbowego, zmiany wymiaru wykorbienia lub korbowodu, zastosowania dodatkowej komory spalania czy podziału wału korbowego i zastosowania przekładni. W końcowej części artykułu przedstawiono zestawienie podsumowujące opisane rozwiązania konstrukcyjne.

EN

In the article the issues to improve the efficiency of the internal combustion spark ignition engine through with the used of high compression ratio were described. The authors construction possibilities in the area of enabling the movement of the cylinder head, use two-element pistons, the crankshaft eccentric bearing, changing the dimension of double crank or connection-rod, using an additional combustion chamber or division of the connection-rod and use of the transmission were shown. In the final part of the article summary of the described construction solutions was presented.

13

Eksperymentalne badania silnika o zwiększonym stopniu sprężania

Malewicz K., Ligus G., Wasilewski M.

Logistyka

|

2015

|

nr 4

4706--4714, CD2

PL

W artykule opisane zostały zagadnienia poprawy sprawności ogólnej spalinowego silnika z zapłonem iskrowym. Autorzy przedstawili możliwości wpływu na parametry pracy silnika przez zwiększenie jego stopnia sprężania. Główna część artykułu dotyczy koncepcji zapobiegania spalaniu stukowemu w silniku o zwiększonym stopniu sprężania. Zaproponowano przeciwdziałanie spalaniu stukowemu poprzez dawkowanie paliwa o podwyższonej liczbie oktanowej. W artykule zaprezentowano również ideę pomiarów, stanowisko pomiarowe niezbędne do przeprowadzania badań eksperymentalnych oraz uzyskane wyniki i rezultaty.

EN

In the article issues to improve the efficiency of the internal combustion spark ignition engine were described. Authors the possibility of influence the engine parameters by increasing the compression ratio were presented. In the main part of the article the concept of knock combustion prevention in engine with a higher compression ratio was referred. Knock combustion counteraction through increased octane number fuel supply was proposed. In the article idea of the measurement with necessary to experimental tests measuring station and the results and outcomes were presented.

14

Analiza wartości stopnia sprężania w silniku podczas spalania mieszanek wzbogaconych w tlen

Nemś A.

Logistyka

|

2015

|

nr 3

3446--3455, CD 1

PL

W pracy omówiono zagadnienie wzrostu mocy jednostkowej silnika samochodowego. Poruszono aspekt doładowania silnika oraz stopnia sprężania. Następnie zwrócono uwagę na fakt, że obecny stan techniki pozwala na zasilanie silnika mieszanką paliwowo-powietrzną wzbogaconą w tlen w sposób ciągły. Takie rozwiązanie pozwala na rozszerzenie parametrów kontrolujących proces spalania w silniku. Niezbędne do tego jest poznanie skutków powodowanych przez tak prowadzony proces spalania. Dlatego w pracy zaprezentowano algorytm wyznaczania adiabatycznej temperatury spalania. Pokazano możliwości jakie daje odpowiednie sterowanie spalaniem w atmosferze wzbogaconej w tlen. Zaprezentowano wybrane dwa rozwiązania sterowania procesem. Podczas spalania mieszanek wzbogaconych ze zwiększoną ilością paliwa wykazano, że niewielkie naddatki tlenu pozwalają znacznie zmniejszyć stopień sprężania w silniku, bez zmiany temperatury spalania. Dla rozwiązania, w którym wraz ze wzrastającym stężeniem tlenu nie zwiększa się ilość spalanego paliwa pokazano, że możliwe jest zwiększenie stopnia sprężania, przy znacznym wzroście ilości tlenu w spalinach.

EN

The paper discusses the problem of the increase of automobile engine unit power. The problem of the engine boost and compression ratio was raised. Then the fact that the current state of the art allows the engine to continuously supply the oxygen enriched mixture was written. This solution allows to extend the parameters for controlling the combustion process in the engine. Necessary to this is to understand the effects of so proceed the combustion process. Therefore, the paper presents an algorithm for determining the adiabatic combustion temperature. The possibilities offered by appropriate control of combustion in an oxygen enriched atmosphere was shown. Selected two process control solutions was presented. During the combustion of mixtures enriched with the increased amount of fuel was shown that small oversize of oxygen allows for greatly reducing the compression ratio of the engine without changing combustion temperature. In case wherein the amount of fuel burned does not increase with increasing oxygen concentration is shown that it is possible to increase the degree of compression with a substantial increase in the amount of oxygen in the exhaust gas.

15

Experimental investigation on performance of a spark ignition engine runs with alcoholic blend-gasoline

Ahmed H. A.

Journal of KONES

|

2015

|

Vol. 22, No. 3

249--256

EN

In this paper performance resulted from a single cylinder spark-ignition engine fuelled with 20% by volume of methanol, ethanol, and butanol was studied and compared to gasoline. The experiments were conducted at variable speed and maximum torques. The conditions of stoichiometric air–fuel ratio at wide-open throttle were used. The tests were perfumed at higher useful compression ratio of the used Iraqi gasoline. The test results show that the higher compression ratio for the tested gasoline was 7.5:1. So an Iraqi conventional gasoline has engine HUCR=7.5:1 and its OST= 19 ºBTDC, this compression ratio can be considered low. Adding 20% of alcoholic blends by volume to gasoline improved the engine performance. Within the tested speed range, alcoholic blends produced higher brake powers, volumetric efficiency and thermal efficiency. In addition, it resulted in lower exhaust gases temperatures. The brake specific fuel consumption of the tested alcoholic blend was higher than that for gasoline.

16

The impact of compression ratio’s change on thermodynamic indicators of combustion in compression ignition engine

Borowski P, Pielecha I.

Journal of Mechanical and Transport Engineering

|

2014

|

Vol. 66, No. 4

5--13

EN

The reduction of the compression ratio in Diesel engines is a common practice in the contemporary development of these engines. The result is the thermodynamic parameters change at the beginning of combustion and consequential on all combustion process. The article presents discussion on research results respecting parameters in cylinder of diesel engine with two different compression ratios. The values of pressure, Indicated Mean Effective Pressure, temperature in cylinder, heat release and fuel consumption were analyzed.

PL

W artykule przedstawiono analizę wyników badań silnika o zapłonie samoczynnym dla dwóch stopni sprężania. W badaniach uwzględniono parametry cylindra. Przedstawiono wartości ciśnienia maksymalnego, średniego ciśnienia indykowanego IMEP, temperatury w komorze spalania, wywiązywania ciepła oraz zużycia paliwa.

17

Crank and rocker piston assembly

Kozak W.

Silniki Spalinowe

|

2013

|

R. 52, nr 1

10-27

EN

The paper presents a qualitative analysis of a crank-and-rocker piston mechanism. In comparison to a conventional piston assembly the mechanism is composed of more elements necessary to convert the reciprocating motion of the pistons to rotary motion of the crankshaft. A greater complexity of the system is balanced by a greater number of advantages particularly visible in the module, composed of four cylinders coupled by the rocker with a single crank journal. A greater number of elements allow an obtainment of better functional flexibility of the mechanism, particularly in terms of the piston movement. This feature can be used to control the course of the engine torque, the heat losses to the cooling system, the reduction of the piston pressure on the cylinder liners (friction and mechanical losses) as well as variation of the compression ratio easily performed during engine operation. The natural characteristics of the four-cylinder module have been highlighted through an internal balancing of the mass forces. The analysis does not contain the elements of design. The design parameters in the analysis are random. They were selected to highlight the properties of the design and show negative and positive features. The relations and remarks included in the paper may turn out useful when designing the mechanism.

PL

W artykule przedstawiono jakościową analizę wahaczowego mechanizmu korbowego. W porównaniu do konwencjonalnego układu korbowego mechanizm zbudowany jest z większej liczby elementów, niezbędnych do zamiany ruchu posuwisto-zwrotnego tłoka na ruch obrotowy wału korbowego. Większy stopień złożoności konstrukcji równoważony jest istotnymi zaletami, szczególnie widocznymi w module konstrukcyjnym, składającym się z czterech cylindrów sprzęgniętych poprzez wahacz z jednym czopem korbowym wału korbowego. Ponadto większa liczba elementów pozwala osiągnąć znaczną elastyczność funkcjonalną mechanizmu, szczególnie w zakresie kształtowania ruchu tłoka. Cecha ta może być potencjalnie wykorzystana do kształtowania przebiegu momentu obrotowego silnika i strat ciepła do układu chłodzenia, do zmniejszenia siły nacisku tłoka na gładź (opory ruchu i straty mechaniczne), jak również zmiany stopnia sprężania silnika, dokonywanej w łatwy sposób podczas pracy silnika. Podkreślono naturalną cechę modułu czterocylindrowego, jaką jest wewnętrzne wyrównoważenie występujących w nim sił masowych. Analiza nie zawiera elementów projektowania. Pojawiające się w niej wartości parametrów konstrukcyjnych maja charakter przypadkowy. Dobierano je w celu uwypuklenia właściwości konstrukcji, pokazania cech negatywnych i pozytywnych. Natomiast przytoczone w artykule związki i uwagi mogą być wykorzystane podczas projektowania mechanizmu.

18

Wpływ stopnia sprężania na wybrane parametry procesu spalania w silniku o zapłonie samoczynnym zasilanym dwupaliwowo gazem ziemnym i olejem napędowym

Luft S., Skrzek T.

Combustion Engines

|

2013

|

R. 52, nr 3

931--935

PL

Artykuł dotyczy zagadnień wpływu stopnia sprężania dwupaliwowego silnika o zapłonie samoczynnym zasilanego gazem naturalnym CNG na wybrane parametry procesu spalania. W ramach badań dokonano rejestracji przebiegu ciśnień w komorze spalania w funkcji obrotu wału korbowego dla różnych wartości stopnia sprężania. Zarejestrowane charakterystyki pozwoliły na wyznaczenie takich parametrów procesu spalania jak: ciśnienie maksymalne Pmax, średnia szybkość narastania ciśnienia (∆p/∆α)śr,maksymalna szybkość narastania ciśnienia (dp/dα)max, w funkcji momentu obrotowego M, oraz stopnia wypalenia dawki x w funkcji obrotu wału korbowego α. Analiza uzyskanych wyników wykazuje silną ich zależność od wartości stopnia sprężania ε silnika dwupaliwowego.

EN

The present paper relates to the problem of the effect of compression ratio of a dual-fuel compression ignition engine fuelled with natural gas (CNG) on selected combustion process parameters. In the course of investigation, there were registered pressure values in the combustion chamber versus crankshaft angle for various compression ratios. The obtained characteristics enabled to determine such combustion process parameters as: maximum pressure Pmax, mean rate of pressure rise (∆p/∆α)śr, maximum rate of pressure rise (dp/dα)max, versus torque M, as well as fuel burnout ratio x versus crankshaft angle α. Analysis of the results indicates strong relationship between the above mentioned parameters and the compression ratio ε of a dual-fuel engine.

19

Wpływ stopnia sprężania na parametry pracy silnika o zapłonie samoczynnym zasilanym dwupaliwowo gazem ziemnym i olejem napędowym

Skrzek T.

Combustion Engines

|

2013

|

R. 52, nr 3

924--930

PL

Artykuł dotyczy zagadnienia wpływu stopnia sprężania w dwupaliwowym silniku o zapłonie samoczynnym zasilanym gazem ziemnym i olejem napędowym, na podstawowe parametry jego pracy. W artykule przedstawiano przyjętą koncepcję zmiany stopnia sprężania silnik, oraz zaprezentowano wybrane wyniki w formie charakterystyk: obciążeniowych jednostkowego zużycia energii, sprawności ogólnej, cieplnej, mechanicznej, zawartości składników w spalinach, a także charakterystyki prędkościowej momentu maksymalnego. Analiza wyników badań prowadzi do wniosków że stopień sprężania w dwupaliwowym silniku o ZS wpływa w sposób istotny na opisane parametry pracy dlatego też powinien być starannie dobrany.

EN

The present paper relates to the problem of the effect of compression ratio of a dual-fuel compression ignition engine fuelled with natural gas (CNG) on basic operational parameters of this engine. There is presented an established concept of the engine compression ratio variations and the obtained results are presented in the form of the following load characteristics: specific energy consumption, overal, thermal and mechanical efficiencies, harmful exhaust emissions as well as speed characteristic of the maximum torque. Analysis of the obtained results permits to conclude that the compression ratio in a dual-fuel compression ignition engine influences substantially the above mentioned parameters. Therefore, it should be set precisely.

20

Wpływ zmiany stopnia sprężania na termodynamiczne wskaźniki procesu spalania w cylindrze silnika spalinowego

Pielecha I., Czajka J., Wisłocki K., Borowski P.

TTS Technika Transportu Szynowego

|

2012

|

R. 19, nr 9

1703--1711, CD

PL

Zmniejszanie geometrycznego stopnia sprężania silników o zapłonie samoczynnym jest powszechną praktyką stosowaną we współczesnym rozwoju takich jednostek. Skutkuje to zmianą parametrów termodynamicznych w cylindrze na początku spalania, a w konsekwencji na przebieg procesów cieplnych i uzyskiwane wskaźniki operacyjne silnika. Artykuł zawiera omówienie wyników badań dotyczących parametrów panujących w cylindrze silnika o zapłonie samoczynnym podczas pracy przy dwóch różnych wartościach geometrycznego stopnia sprężania. Analizie poddano przebiegi ciśnienia w cylindrze, wartości średniego ciśnienia indykowanego, temperatury ładunku w cylindrze, wywiązywania ciepła oraz jednostkowego zużycia paliwa podczas pracy silnika.

EN

A reduction of the compression ratio in diesel engines is a common trend in the development of these sources of propulsion. The paper discusses the results of the investigations related to the parameters of a diesel engine during operation at two different values of the engine compression ratio. The author analyzes the courses of the cylinder pressure, mean indicated pressure, cylinder temperature, heat release and unit fuel consumption.