Wyniki wyszukiwania - Biblioteka Nauki

1

Description of a three-phase, four-wire system with a nonlinear receiver and an asymmetric voltage source using CPC power theory

100%

Zajkowski K. , Woźniak M.

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tom Vol. 5, No. 3

47--66

EN

This article mathematically describes a three-phase, four-wire circuit in the case of a nonlinear, unbalanced load, asymmetry of the power source with a periodic, non-sinusoidal waveform. This description uses Currents' Physical Components (CPC) power theory for threephase circuits. Determining the energy flow between the source and the load is possible by decomposing the phase current into components depending on the physical nature of the phenomena in this circuit. Mathematical relationships were determined enabling decomposition into components depending on the direction of energy flow and the causes of their creation. A calculation example using the determined relationships and calculation results has been presented. The presented computational concept is important for mathematical analyzes in circuits with nonlinear three-phase receivers. Knowing the nature of physical phenomena, it is possible to perform measures that limit the value of the current supplying the load.

2

Problems with glow plug - a review

80%

Woźniak M. , Ozuna G. , Siczek K.

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tom R. 60, nr 3

11--30

EN

Despite the development of hybrid and electric vehicles, a many-million population of cars with combustion engines, and particularly CI engines occurs on the roads. Also, many stationary CI engines are still utilized. Despite their improved technologies and characteristics the modern CI engines negatively affect an environment due to cold starting problems. Below 0°C, engine starts are problematic due to the decreased battery performance and the spray characteristics, the increased ignition delay time, and the engine oil viscosity. Therefore, various glow plugs are applied to facilitate this process. Types, features, and applications of glow plugs in various engines have been discussed in the paper. One case of failure of glow plug has been presented in the article, including the cause of it.

3

Study on selected parameters of engine with the active combustion chamber

80%

Głogowski M. , Woźniak M. , Szydłowski T. , Siczek K.

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tom R. 62, nr 3

3--12

EN

The present study was focused on the combustion engine with a variable compression ratio (VCR), namely the four-stroke air-cooled engine with the active combustion chamber (ACC). An indicated pressure, torque, power, and specific fuel consumption of that engine were investigated experimentally as a goal of the present study. Experiments were conducted using two versions of an engine. Two parameters particularly influencing the ACC engine performance including the maximum compression ratio CRmax and the indicator γfm determining the correct operation of the ACC system, were described. It was found that the ACC engine allowed avoiding detonation combustion without changing the amount and composition of the combustible mixture, and even without delaying the ignition advance angle. In addition, the possible range of control of the combustion process allowed the ACC engine to operate with different types of hydrocarbon fuels, for example, in the form of petrol with various alcohol admixtures. The very intense flow of the combustible mixture inside the cylinder of the ACC engine allowed describing the combustion in the ACC engine with zero-dimensional mathematical models with the dual Vibe function providing the proper characterization of the heat release process. The use of very high maximum compression ratios allows the ACC engine to operate to a certain extent as a Homogeneous Charge Compression Ignition (HCCI) engine with high lambda coefficients.

4

Analysis and assessment of the reliability of the operation process of a complex, diagnosed technical facility in 5-value logic

61%

Duer S. , Woźniak M. , Stawowy M. , Harničárová M. , Zajkowski K. , Duer R.

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tom Nr 4

60--70

EN

What the article talks about are the difficulties of figuring out how reliable the workings of a complicated technological object are, especially when using a five-valued logic-based diagnostic method. The foundation for conducting dependability studies on technological objects is the utilization of prepared models that depict operational processes. The present study aims to build and provide a comprehensive description of a five-state model that characterizes the operational process of the diagnosed facility. The operational states that hold significance are the states of the object being tested, as diagnosed within the framework of 5VL-value logic. The model of the exploitation process that was constructed was further validated using simulated experiments. The outcomes of these comparative tests yield the calculated probabilities of the tested thing existing in its distinct conditions. The estimated time frames of occurrence of the recognized states in the object were determined based on the probability of occurrence of the diagnostic states, which were derived from the reliability features of the tested object.