Wyniki wyszukiwania - BazTech

1

Study of Atkinson cycle in two-stroke diesel engine with opposed pistons

Mitianiec Władysław

Combustion Engines

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2019

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R. 58, nr 3

121--128

EN

The paper presents possibilities of change working parameters of two-stroke diesel engine with opposed pistons. Obtaining of higher engine efficiency is realized by applying of Atkinson cycle. Modification of scavenging process by changing pistons' position connecting with two crankshafts enables asymmetrical scavenge timing. Decreasing of shorter time of closing exhaust ports before compression process and longer expansion process give higher engine work and with high charging ratio increases engine power. These types of engines are recently recommended for power plant stations. The paper includes full analysis of engine work with scavenge and combustion processes for different timing phases based on geometry of the CI Leyland L60 engine by using of CFD modelling and own 0D model. Simulation tests indicate a high scavenge efficiency, good penetration of injected fuel and fast combustion process. The work contains figures of pressure, temperature traces and emission of main chemical species in exhaust gases with comparison of engine works for different timing phases. Atkinson cycle in two-cycle work of engine and full combustion process enables to achieve high total efficiency. The study is an input for realization of such processes in a future of power plant engines with different fuelling systems.

2

Thermodynamic indexes of Atkinson cycle combustion engine operation under simulated traffic conditions

Cieślik W., Pielecha I.

Journal of Mechanical and Transport Engineering

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2014

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Vol. 66, No. 1

5--17

EN

This paper presents the results of indicator research of transient states of an engine operating in the Atkinson cycle. Such states are the most frequently observable ones during engine operation and are a subject of many researches and development works. The investigations were carried out using a fast varying data acquisition system using engine speed sensor and the pressure sensors fitted in the spark plug. The analysis were performed under the conditions of engine start and acceleration speed. Operating characteristics from research are described by a coefficient of variation (CoV) of indicated mean effective pressure and the heat release parameters. These parameters allow the operating characteristics of the engine. Hence they are one of the main directions of researches.

PL

W artykule przedstawiono analizę indykatorową z cyklu na cykl w warunkach nieustalonych silnika o zapłonie iskrowym pracującego w obiegu Atkinsona. Warunki te są najczęściej obserwowane podczas pracy silnika i są przedmiotem wielu badań. Badania prowadzono z wykorzystaniem aparatury do rejestracji sygnałów szybkozmiennych, czujnika prędkości obrotowej oraz czujnika ciśnienia indykowanego umieszczonego w świecy zapłonowej. Analizie poddano warunki rozruchu i akceleracji silnika. Uzyskaną w badaniach charakterystykę pracy z cyklu na cykl opisano za pomocą współczynnika zmienności (CoV) średniego ciśnienia indykowanego oraz wielkości charakteryzujących wywiązywanie się ciepła. Parametry te pozwalają na opis jednostki napędowej i są jednym z głównych kierunków badań cyklicznych zmian pracy silnika spalinowego.

3

Termodynamiczna analiza pracy silnika z cyklu na cykl z obiegiem Atkinsona

Pielecha I., Cieślik W., Borowski P.

TTS Technika Transportu Szynowego

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2013

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R. 20, nr 10

3183--3192

PL

W artykule przedstawiono analizę indykatorową z cyklu na cykl silnika o zapłonie iskrowym pracującego w obiegu Atkinsona. Charakterystyka pracy z cyklu na cykl opisywana jest najczęściej przy pomocy współczynnika zmienności (CoV) średniego ciśnienia indykowanego oraz przez wielkości charakteryzujące wywiązywanie ciepła. Parametry te pozwalają na charakterystykę jednostki napędowej i są jednym z głównych kierunków tematów badawczych dotyczących cyklicznych zmian pracy silnika spalinowego.

EN

This paper presents an analysis of indicators from cycle to cycle in spark ignition engine operating in the Atkinson cycle. Operating characteristics from cycle to cycle is described by a coefficient of variation (CoV) mean indicated pressure and the heat release parameters. These parameters allow the operating characteristics of the engine, is one of the main directions of research.

4

Increase of the total efficiency using the Atkinson cycle in the spark ignition engine

Sendyka B., Sochan A.

Journal of KONES

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2009

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Vol. 16, No. 2

407-411

EN

The paper presents the results of investigations performed on a combustion engine with Atkinson cycle included and application of variable valve timing. Investigations were carried out at constant rotational speed 2500 and 3500 RPM and at throttle opening 25% and 50%. Influence of the advance/delay angle of inlet valves closing on formation of exhaust gases toxic components such as: carbon monoxide, hydrocarbons and nitric oxides was presented. Basing on the obtained results difference of toxicity of exhaust gases before and after application of phase shifter and their concentration in places of total efficiency increments was demonstrated. Especially The Atkinson cycle comparing with conventional Otto cycle, characteristics of the electric motor applied in Toyota Prius generation, starting and work of engines (combustion engine and electric motor) during vehicle standstill, relation of specific fuel consumption in function of rotational speed for a Toyota Prius engine, generation II, in total efficiency of engines with Atkinson cycle and Mitsubishi GDI in function of rotational speed, relative increase in total efficiency as rotational speed function, influence of intake valves opening angle on concentration in exhaust gases: carbon monoxide, hydrocarbons and nitric oxides at diferrent throttle opening values are presented in the paper.

5

The description of the total efficiency of 2SZ-FE engine with the variable valve timing

Sendyka B., Sochan A., Noga M., Rodak Ł.

Journal of KONES

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2007

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Vol. 14, No. 2

401-407

EN

In this paper there were conducted tests of the combustion engine with the Atkinson cycle and with applying variable valve timing. There was described the 2SZ-FE engine characteristics and assigned the total efficiency before and after application of the phase shifter. Secondly, there was determined the thermal efficiency of the single engine work cycles and also engine 's total efficiency by using the optoelectronic pressure sensor and mathematical programme. After that, it was available to present the range of the variable valve timing. Atkinson system, phases of 2SZ-FE engine timing gear, the total efficiency distribution during 75 % of throttle opening and when inlet valves are open, the total efficiency increase during 75 % of throttle opening, the total efficiency distribution during 50 % of throttle opening and when suction valves are open, the total efficiency increase during 50 % of throttle opening, the total efficiency distribution during 25 % of throttle opening and when inlet valves are opened, the total efficiency increase during 25 % of throttle opening, the total efficiency distribution with application of phases shifter are presented in the paper.

6

Carnotization of the power cycle of internal combustion reciprocating engine

Mendera K. Z.

Journal of KONES

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2007

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Vol. 14, No. 4

257-264

EN

There are two ways to increase the thermodynamic efficiency of the engine cycle known as the carnotization of the power cycle. The first is to ensure the highest possible maximum parameters and the second is to allow the working medium to expand further than in the standard cycle. This is known generally as the over-expansion or extended expansion cycle. This paper presents theoretical and numerical investigations into the effect of extended expansion on the thermal efficiency and mean effective pressure. The performance of an air standard Atkinson cycle was considered and compared to that of the Sabathe cycle. The Miller version of extended expansion air standard cycle was analysed for both naturally aspirated and supercharged engine. Additionally, the numerical simulation of supercharged engine was also carried out. In both cases, two inlet valve closing strategies were evaluated (Early Intake Valve Closure-EIVC and Late Intake Valve Closure - LIVC). From the present investigation it is concluded that the extended expansion concept is an effective way of the carnotization of the power cycle of internal combustion reciprocating engine. The main conclusion resultanting from presented paper deals controls of closing angle of inlet valve which is to be an effective way of influence on the course of temperature changes of the working charge and what should be useful for the level emission decreasing of nitrous oxides.

PL

Karnotyzacja obiegu silnika spalinowego tj. poszukiwanie sposobu podwyższenia jego sprawności może dotyczyć zarówno źródła górnego (sposobu doprowadzania ciepła) jak i dolnej przemiany odprowadzania ciepła Karnotyzacja źródła dolnego to wszelkie próby zmierzające do przedłużenia ekspansji czynnika roboczego. W pracy przedstawiono teoretyczną i numeryczną analizę wpływu przedłużenia ekspansji na sprawność i ciśnienie średnie obiegu silnikowego. Przeprowadzono analizę teoretyczną obiegu Atkinsona, a jej wyniki porównano z klasycznym obiegiem Sabathe. Dokonano także analizy obiegu Millera zarówno dla silnika niedoładowanego jak i doładowanego oraz zrealizowano badania symulacyjne obiegu doładowanego silnika z przedłużoną ekspansją. W obu przypadkach analizę przeprowadzono zarówno dla wczesne zamknięcie zaworu dolotowego jak i późnego zamknięcie zaworu dolotowego. Przeprowadzone badania usprawiedliwiają tezę, iż koncepcja przedłużonej ekspansji może być skutecznym sposobem karnotyzacji obiegu tłokowego silnika spalinowego. Główny wniosek wynikający z prezentowanego artykułu dotyczy sterowania kątem zamknięcia zaworu dolotowego, może być efektywnym sposobem oddziaływania na przebieg zmian temperatury czynnika roboczego i co powinno być przydatne dla ograniczania poziomu emisji tlenków azotu.