Wyniki wyszukiwania - Biblioteka Nauki

1

Theoretical and real working cycle of four stroke piston engine

100%

Ambrozik A. , Jankowski A. , Slezak M.

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tom Vol. 14, No. 2

9-18

EN

The most important problems concerning analyses of generalized computational thermodynamical working cycle of the four-stroke combustion engine are result of the identification of real indicating diagram. The analysis of working cycle of the four-stroke combustion engine is realized from point of view heat efficiency, the average theoretical cycle pressure, as well as of the influence of the organization working cycle on the value of the maximum pressure in the cylinder of a combustion engine. A novel mathematical model reflecting elementary processes occurring in the cylinder of a combustion engine and connected with it intake and exhaust systems of engine were proposed. Thermodynamical working cycles of four-stroke piston engines, theoretical working cycle of a four-stroke piston engine, thermal efficiency of the theoretical thermodynamic generalised engine work cycle, mean theoretical pressure of the generalised thermodynamic work cycle of a combustion engine, maximum pressure of the theoretical thermodynamic work cycle of a combustion engine, comparative working cycles of piston engines, real working cycle of four-stroke piston engines are presented In het paper. The methods of analyses and calculations referring these engines work cycles were presented. These method show advisability and needs of using them to theoretical calculations and analyses of real work cycles. Generalized engine work cycle was proposed.

2

The identification of model parameters for a semi-empirical model of working process in the compression-ignition engine

100%

Brzozowski K. , Nowakowski J.

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tom Vol. 17, No. 3

41-48

EN

The paper concerns the identification process applied for a semi-empirical model of working process in the CI engine. The identification is based on pressure courses in the cylinder recorded during the experimental measurements on the test stand and is performed for estimation of values of the model parameters. Appropriate estimated values of the model parameters ensure minimization of the difference between measured and modelled pressure courses in the cylinder. The identification process can be divided into two stages. The first stage concerns identification of discrete values of the model parameters for a set of discrete engine operating conditions. The task of discrete identification is formulated as a dynamic optimisation task which is sohed using a genetic algorithm. The accuracy of the identification process is evaluated by comparison of measured and calculated values of main parameters which characterize the working cycle such as: the mean indicated pressure, thermal efficiency, the mean indicated pressure in working part of the cycle, maximal pressure of the cycle, the mass of the medium in the cylinder and the crankshaft angle for which the maximal pressure occurred. The second stage concerns generalization of the results for any technically possible engine operating conditions which is sohed by means of approximation. Feed-forward multilayer artificial neural networks are usedfor the approximation. The accuracy of the identification and some examples of verification of the model predictions are presented as well.

3

Novel method appointing of the effective heat release coefficient during combustion process based on real indicator diagram

88%

Jankowski A. , Ambrozik A. , Jankowska-Sieminska B. , Ślęzak M.

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tom Vol. 14, No. 4

133-142

EN

An object of the paper is a novel method of effective heat release coefficient appointing during combustion process of the based on the real indicator diagram. The process quality of the heat release during process of combustion is evaluated by value of the effective heat release coefficient. Accepted assumptions at appointing effective coefficient of heat release refer to acceptable that thermodynamical parameters of the working charge according to points of the real indicator diagram and the computational diagram are such the same, the maximum pressure of real working cycle of the engine is equal to the pressure of the computational cycle, work of the working charge performed in period from point of closing of the inlet valve to point of the beginning of the exhaust process are for both considered working cycles equal, heat values of the carried to the real and computational cycle are such the same. The method of appointing of the self-ignition delay period is presented in the paper, using to this end intersection point of two graphs of temperature course of the working charge prepared for the first phase of combustion process. Other methods appointing characteristics is suggested in paper basing on the real indicator diagram. The graphic illustration of the preparing method of characteristics of the relative quantity of the heat release during combustion process is illustrated in paper.

4

Analiza cyklu roboczego manipulatora o czterech stopniach swobody

63%

Cekus D. , Skrobek D.

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tom T. 27, nr 58

13--17

PL

Niniejsza praca przybliża zagadnienia związane z modelowaniem manipulatora o czterech stopniach swobody i wyznaczaniem obciążeń jego napędów podczas cyklu roboczego. Zaproponowany algorytm obliczeń pozwala zweryfikować poprawność dobranych napędów poszczególnych członów analizowanego obiektu. Praca została uzupełniona wynikami z przeprowadzonych przykładowych badań symulacyjnych dla zadanych wymuszeń kinematycznych.

EN

This paper introduces problems of the modelling of four degrees of freedom manipulator and the determination of loads of its drives during the working cycle. The proposed computational algorithm makes it possible to verify the correctness of selected drives of individual members of the analyzed object. The results of simulation studies carried out for given sample kinematic excitations have been presented.

5

The cascade exchange pressure supercharger of transport diesel with deep cooling cycle air

63%

Krajniuk A. , Krajniuk A.

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tom T. 6, z. 3

67-76

EN

The new principle of the organisation of working process of the combined supercharging system of transport diesel with the Cascade Pressure Exchanger (CPE) has been described. It allows considerably to raise level of forcing of the engine by supercharging at the expense of expansion of effective air supply area and coolings of supercharging air to temperature below an ambient. Substantive postulates of imitating model of work of combined engine(CICE) have been stated. Some results of calculation-experimental investigations of supercharging system of the engine 6×Í12/14 have been given. It confirms the possibility of the essential improvement tractive and fuel-economic factors of the transport installations in broad range of the working conditions.

6

The new devices of gas-turbine engines of ground transport on the basis cascade pressure exchanger of krajniuk

51%

Krajniuk A.

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tom T. 6, z. 2

107-119

EN

Main trends of perfection of gas-turbine engines (GTE) of transport plants by application of principles of the cascade pressure exchange (CPE) for air compression in the working cycle of gas-turbine plant have been analyzed. The principle of action and performances of work of heat compressor CPE realizing compression of working body on the whole at the expense straight convert inputting heat in disposing work of torrent with insignificant distraction mechanics work from shaft selection of power has been described. The results of computational investigation of four variants of the GTE working process organization on the basis of the two-staged compression assembly with intermediate cooling and heating of air-gas medium have been adduced. Application of units CPE in the capacity of compressing stage GTE opens the prospect of adaptations GTE performance by conditions of work in the capacity of forcing units of overland transport.

7

Thermal compressor of cascade exchange by pressure

51%

Krajniuk A.

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tom T. 5, z. 1

15-22

EN

A new method of organization of working cycle of device of direct transformation of heat in the located work of compression of air, based on principle of cascade exchange by pressure, is exposed; the results of pre-selection of basic dimensional and structural parameters of thermal compressor of cascade exchange by pressure are adduced; some special features of its working process are considered; main directions of perfection of working cycle of thermal compressors of cascade exchange of pressure are shown.