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The influence of the ignition system characteristic on the two-stroke engine operating conditions

Fiedkiewicz Ł., Cieślik W., Pielecha I.

Journal of Mechanical and Transport Engineering

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2016

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Vol. 68, No. 4

5--15

EN

This paper presents an indicator analysis of the impact of the characteristics of an electronic ignition system on the operating conditions of a two-stroke spark ignition engine. The tests were carried out on a single-cylinder two-stroke engine equipped with a combustion pressure sensor using the apparatus for recording fast-varying signals. The influence of changes of the ignition angle of advance at constant engine speeds on the engine operating indicators was analysed. The assessment of the impact of the changes to the settings of the ignition system was analysed in terms of thermodynamic conditions: combustion pressure and average effective pressure. It was found that the ignition angle of advance has positive influence on engine operating conditions and uniformity of engine operation. As a measure of non-uniformity of engine operation were accepted the coefficient of variation of the engine speed and the mean indicated pressure. It was indicated that, along with the ignition angle of advance, the indicators of two-stroke engine operation also increase with simulta-neous increase in the non-uniformity of engine operation.

PL

W artykule przedstawiono analizę indykatorową wpływu charakterystyki elektronicznego układu zapłonowego na warunki pracy silnika dwusuwowego o zapłonie iskrowym. Badania prowadzono na jednocylindrowym silniku dwusuwowym wyposażonym w czujnik ciśnienia spalania z wykorzystaniem aparatury do rejestracji sygnałów szybkozmiennych. Analizie poddano wpływ zmiany kąta wyprzedzenia zapłonu przy ustalonych prędkościach obrotowych silnika na wskaźniki jego pracy. Ocenę wpływu zmian nastaw układu zapłonowego analizowano w aspekcie warunków termodynamicznych: ciśnienia spalania oraz średniego ciśnienia użytecznego. Stwierdzono pozytywny wpływ wyprzedzenia zapłonu na warunki pracy silnika oraz na jego równomierność pracy. Jako miarę nierównomierności jego pracy przyjęto współczynnik zmienności prędkości obrotowej i średniego ciśnienia indykowanego. Wykazano, że wraz z wyprzedzeniem zapłonu zwiększają się wskaźniki pracy silnika dwusuwowego z jednoczesnym zwiększeniem nierównomierności jego pracy.

2

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

Mitianiec W.

Combustion Engines

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2016

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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.

3

Badania doświadczalne a dokładność opracowanego modelu

Szkarowski A., Janta-Lipińska S.

Rocznik Ochrona Środowiska

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2015

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Tom 17, cz. 1

576--584

EN

For an extensive range of experimental studies one is constantly looking for the way which would shorten our worktime as well as decrease the amount of measurements and at the same time not worsen the credibility of set research assumptions. One way is the method of planning experiments or elaborating a theoretical physico-mathematical model. The authors’ team decided to elaborate a new physico-mathematical model, as a work line, which determined the range of optimal values for efficiency and ecology ratio of fuel combustion. While conducting the experimental research the authors’ team dealt mainly with the modernization of industrial boilers and heaters to improve their operation ratio in respect of efficiency and ecology. Thanks to the created model the assessment of combustion optimality was performed from the viewpoint of both efficiency and ecology made on the basis of energo-ecological criteria elaborated by the authors. The use of model allowed the authors to considerably decrease the amount of required work mode change of boilers and conducted measurements on real industrial-heating objects. The studies were performed on the real objects of URAN SPB and TERA companies. During the experimental works one examined the influence of quantitive and qualitive ratio of distributing the air into combustion zone as well as boiler power on the emission of CO and NOx. The studies were conducted on identical steam boilers DKVR-20-13 equipped with various fan burners: GMGB-5,6, GMGm-5 and GMG-7. The achieved results of experimental research were set with the previously elaborated mathematical model in order to determine the adequacy rate of achieved results (fig. 1–2). The credible approximating dependence that determined the experimental data was made up by the function including the determination coefficient above 0.95. The values of approximating factors for the particular measurements were set in the table (1–4).