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1

Harmonic Analysis in the Power Supply System of a Selected Single-Phase Industrial Robot

Ziółkowski Eugeniusz

Journal of Casting & Materials Engineering

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2025

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Vol. 9, no. 3

45--49

EN

The selection of industrial robots in technological lines is primarily based on their technical characteristics, such as the type of construction, the number of axis, reach, maximum load, and power supply parameters (power consumption in single-phase or three-phase systems). In the overall energy balance, the transient states and the harmonics of voltages and currents in the power supply system of the selected industrial robot are also operationally significant. The article presents the results of harmonic analysis of voltage and current in the power supply system of a chosen industrial single-phase robot.

2

Experimental Results of Diver Detection in Harbor Environments Using Single Acoustic Vector Sensor

Mahmoud Saier, Saleh Louay, Chouaib Ibrahim

Archives of Acoustics

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2025

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Vol. 50, nr 2

173--185

EN

This paper addresses the detection of divers with an open-circuit scuba. An acoustic vector sensor (AVS), which contains four channels, one for the pressure component, and three for orthogonal particle velocity components is proposed to be used. A novel covariance matrix analysis (CMA) method is presented for estimating the signal power using AVS in three-dimensional measurements. This method is based on solving a quartic equation that relates the determinant and trace of the AVS covariance matrix to the reciprocal of the signalto-noise ratio (SNR) in a three-dimensional isotropic acoustic field with spherical isotropic noise. This method is compared with two traditional methods: the AVS pressure channel power, and the minimum variance distortionless response (MVDR) beamformer, in estimating the acoustic power associated with the diver’s breathing. Experimental data from sea trials demonstrate the capability of all three methods to reconstruct the waveform of the acoustic diver signal and highlight the periodic breathing patterns. The diver’s breathing rate and corresponding power are estimated using the fast Fourier transform (FFT) of the power signal, therefore serving as a key signature for diver detection. The experiment demonstrates that the CMA method gives better diver detection index compared to the other two methods.

3

Subzero temperatures and low-frequency impact on MFC piezoelectric transducers for wireless sensor applications

Płaczek Marek Łukasz, Degefa Tolera G., Kokot Grzegorz

Eksploatacja i Niezawodność

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2024

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Vol. 26, no. 2

art. no. 183316

EN

This research paper is a continuation of a prior study [12]that focused on the positive temperature range. The current work investigates the behavior of a laminated Macro Fiber Composite (MFC) piezoelectric transducer when exposed to negative temperatures. The study aims to understand the sensitivity of the transducer under varying ambient temperatures and frequencies, particularly for applications in wireless sensor networks. The integrated Macro Fiber Composite piezoelectric transducer is both theoretically modeled and empirically verified. Experimental tests involve subjecting the laminated MFC piezoelectric transducer to sinusoidal forces generated by an electro-pulse waveform generator, while a thermal chamber is used for temperature control. Controlled displacement is applied to the transducer at low-frequency (5 to 25 Hz) ranges and different moderate temperatures (0 to -40 degrees Celsius). The results highlight the significant influence of temperature and excitation frequency on the generated voltage by the MFC transducer.

4

Wykrywanie zdarzeń awaryjnych w silnikach indukcyjnych na podstawie analizy danych z rejestratorów zakłóceń

Sajewicz Dariusz, Łaguna Wojciech, Chmielak Waldemar

Przegląd Elektrotechniczny

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2023

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R. 99, nr 1

207--210

PL

Celem artykułu jest wykazanie skuteczności nowo opracowanych metod detekcji uszkodzeń opartych na analizie danych z rejestratorów zakłóceń. W trakcie prac badawczych wyekstrahowano najbardziej istotne cechy sygnałów prądów w dziedzinie częstotliwości. Pozyskane cechy stanowiły podstawę budowy probabilistycznego klasyfikatora zdarzeń awaryjnych. Detekcja uszkodzeń dotyczy wykrywania: pękniętych prętów wirnika i stopnia jego degradacji oraz awarii łożysk na wale silnika. Przeprowadzone badania potwierdzają wysoką skuteczność wykrywania uszkodzeń we wszystkich rozpatrywanych obszarach.

EN

The aim of this paper is to demonstrate the effectiveness of developed fault detection methods based on the analysis of data from fault recorders. During the research work, the most significant features of current signals in the frequency domain were extracted. The extracted features provided the base for building a probabilistic classifier of fault incidents. The fault detection concerned the detection of cracked rotor cages and the degree of its degradation as well as the failure of bearings on the motor shaft. The conducted research confirms the high efficiency of detection faults in all areas concerned.

5

High impedance fault detection in low voltage overhead distribution based wavelet and harmonic indices

Albanna Enaam, Al-Rifaie Alya Hamid, Al-Karakchi Ahmed A. Abdullah

Przegląd Elektrotechniczny

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2023

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R. 99, nr 7

243--246

EN

High-impedance fault HIF occurs when an energized conductor makes contact with a surface with a high impedance. Conventional overcurrent protection cannot detect this fault due to the low fault current, and there is no effective protection for HIFs. This paper introduces a novel method for detecting HIFs in low voltage distribution systems by decomposing neutral current using Wavelet and FFT. Modeling HIF fault data in Matlab to analyze the proposed scheme. Simulations demonstrate that the proposed method can accurately detect HIF and distinguish it.

PL

Błąd wysokiej impedancji HIF występuje, gdy przewodnik pod napięciem styka się z powierzchnią o wysokiej impedancji. Konwencjonalne zabezpieczenie nadprądowe nie jest w stanie wykryć tej usterki z powodu niskiego prądu zwarciowego i nie ma skutecznej ochrony dla HIF. W artykule przedstawiono nowatorską metodę wykrywania HIF w systemach dystrybucji niskiego napięcia poprzez dekompozycję prądu neutralnego za pomocą funkcji Wavelet i FFT. Modelowanie danych o błędach HIF w Matlabie w celu analizy proponowanego schematu. Symulacje pokazują, że proponowana metoda może dokładnie wykrywać i rozróżniać HIF.

6

Efficient and robust medical image watermarking based on optimal subband tree structuring and discrete fractional fourier transform

Chacko Anusha, Chacko Shanty

Computer Assisted Methods in Engineering and Science

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2023

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Vol. 30, no. 4

557--581

EN

In order to solve the security problems associated with medical information and improve the robustness of watermarking algorithms for medical images, a unique approach to watermarking based on block operations is presented. This study considers the medical images as the cover image, with the watermark logo considered secret information that needs to be protected over the wireless transmission in telemedicine. In the embedding phase, input with the discrete fractional Fourier transform is first applied to the input, and then level 2 wavelet decomposition is carried out to determine the optimal sub-band tree. For each tree node on level 2, the approximated and detailed coefficient is determined through the feature analysis perspective. The novelty of the adopted methodology is its simplified transformation and embedding process. Upon receiving a complex matrix, it separates the real part from imaginary part where block transformation is carried out for embedding the watermark pixels. In the extraction phase, just a reverse operation is performed. The watermarking evaluation is performed by simulating various image processing attacks on watermarked medical images. The simulation outcome demonstrates the effectiveness of that proposed watermarking scheme against various attacks. The proposed watermarking technique is robust under various attacks based on image statistics such as PSNR, BER, and the correlation coefficient.

7

PCG signal classification using a hybrid multi round transfer learning classifier

Ismail Shahid, Ismail Basit

Biocybernetics and Biomedical Engineering

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2023

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Vol. 43, no. 1

313--334

EN

Diagnosis of cardiovascular diseases using Phonocardiography(PCG) is a challenging task as signal itself is cyclo-stationary. It has spectral contents which are overlapped by multiple sources having similar spectral contents but acting as noise. Moreover, length variation in the signals and sampling using different equipment also make analysis of these signal a testing task. In this research, authors have introduced a hybrid technique to counter the variations just mentioned. Our technique is composed of high resolution spectrum generation, conversion of spectral contents to Spectrogram and multi round training. Use of fixed length spectral contents makes system independent of signal length. By using Spectrogram, the deep features can be extracted from spectrum which are used as an input to Pre-trained networks (PTNs). Finally, transfer learning is applied with multiple rounds of training. The introduced methodology is validated using multiple datasets having different PCG signals, sampling frequency, signals length and signal quality. From the reported results, it is evident that Chirplet Z transform (CZT) based Spectrogram can be utilized for mutlticlass classification. If CZT based Spectrograms are passed through multi rounds of training, then accuracy can be further increased. The reported results are accurate to 99% in the case of testing for best case scenarios and even in worst case, the results dont fall below 85%. However, an important observation is that they are consistent across the experimental protocols. The computational cost associated with the introduced technique is low which makes it suitable for hardware implementation.

8

Application of the Acoustic Emission Technique for Damage Identification in the Fiber Reinforced Polymer Composites

Samborski Sylwester, Korzec Izabela

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no. 1

210--221

EN

A set of experiments having in target determination of fracture resistance was performed on the Fiber Reinforced Polymer (FRP) composites specimens with an additional monitoring of damage onset and evolution with a so-called Acoustic Emission (AE) technique. The AE technique is a non-destructive material testing method, which enables registering the phenomena usually not audible with a human ear - the frequency bands lay between 100 and 1000kHz. For the FRP composites this enables monitoring various damage phenomena - matrix cracking, delamination, fiber cracking etc. by acquisition and subsequent analysis of several AE parameters: number of hits, number of counts, amplitude or energy of the signal. In the paper advantages of a deeper analysis of the raw AE signal was presented with an application of the Fast Fourier Transform (FFT), leading to a more detailed damage identification along the whole loading procedure. The study proved the usability of the AE method in damage monitoring of the FRPs; a bundle of illustrative examples of chosen acoustic emission parameters’ evolution displayed on the background of the load applied to composite specimens was presented and interpreted.

9

Fault diagnosis of induction motors rotor using current signature with different signal processing techniques

Guezam Abdelhak, Bessedik Sid Ahmed, Djekidel Rabah

Diagnostyka

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2022

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Vol. 23, No. 2

art. no. 2022201

EN

The popularity of asynchronous machines, particularly squirrel cage machines, stems from their inexpensive production costs, resilience, and low maintenance requirements. Unfortunately, potential flaws in these devices might have a negative impact on the facility's profitability and service quality. As a result, diagnostic tools for detecting flaws in these types of devices must be developed. Asynchronous machine problems can be diagnosed using a variety of methods. Signal processing techniques based on extracting information from characteristic quantities of electrical machine operation can provide highly useful information about flaws. The purpose of this research is to develop efficient algorithms based on numerous signal processing approaches for correctly detecting asynchronous cage machine rotor defects (rotor bar ruptures).

10

Analysis of the backlash in the single stage cycloidal gearbox

Król Roman

Archive of Mechanical Engineering

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2022

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LXIX, nr 4

693--711

EN

In this paper the analysis of backlash influence on the spectrum of torque at the output shaft of a cycloidal gearbox has been performed. The model of the single stage cycloidal gearbox was designed in the MSC Adams. The analysis for the excitation with the torque and the analysis with constant angular velocity of the input shaft were performed. For these analyses, the amplitude spectrums of the output torque for different backlashes was solved using FFT algorithm. The amplitude spectrums of the combined sine functions composed of the impact to impact times between the cycloidal wheel and the external sleeves were computed for verification. The performed studies show, that the backlash has significant influence on the output torque amplitude spectrum. Unfortunately the dependencies between the components of the spectrum and the backlash could not be expressed by linear equations, when vibrations of the output torque in the range of (350 Hz – 600 Hz) are considered. The gradual dependence can be found in the spectrum determined for the combined sine functions with half-periods equal impact-to-impact times. The spectrum is narrower for high values of backlash.

11

Introduction to Fourier analysis using IT tools of Laboratory of Technical Aids of Teaching IF UJ

Wietecha Tomasz, Kurzydło Piotr M., Bogacz Bogdan F.

Science, Technology and Innovation

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2021

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Vol. 12, no. 1

10--15

EN

The general aim of this article is to present didactic aspects of familiarizing students with the Fourier analysis. This didactic process issues through the use of IT tools of Laboratory of Technical Aids of Teaching is discussed. There are four separate computer stations, differing in software, where students learn step by step: composing signals from single harmonics, visualization through images of rotating vectors of harmonic signal composition, operation of a virtual generator of a given number of harmonics and elements of the CMA Coach system in the context of signal analysis. The applied didactic methods are aimed at students of biophysics for whom the Fourier analysis is of practical importance.

12

FFT-based simulation using a reduced set of frequencies adapted to the underlying microstructure

Gierden Christian, Waimann Johanna, Svendsen Bob, Reese Stefanie

Computer Methods in Materials Science

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2021

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Vol. 21, No. 1

51--58

EN

Instead of the classical finite element (FE) based microstructure simulation, a Fast Fourier transform (FFT) based microstructure simulation, introduced by Moulinec and Suquet (1994, 1998), also enables the computation of highly resolved microstructural fields. In this context, the microscopic boundary value problem is captured by the Lippmann-Schwinger equation and solved by using Fast Fourier transforms (FFT) and fixed-point iterations. To decrease the computational effort of the fixed-point solver, Kochmann et al. (2019) introduced a model order reduction (MOR) technique based on solving the Lippmann-Schwinger equation in Fourier space with a reduced set of frequencies. Thereby, the accuracy of this MOR technique depends on the number of used frequencies and the choice of frequencies that are considered within the simulation. Instead of the earlier proposed fixed (Kochmann et al., 2019) or geometrically adapted (Gierden et al., 2021b) sampling patterns, we propose a sampling pattern which is updated after each load step based on the current strain. To show the precision of such a strain-based sampling pattern, an elasto-plastic two-phase composite microstructure is investigated.

13

Fault Analysis of Worm Gear Box Using Symlets Wavelet

Thamba Narendiranath Babu, Thatikonda Venkata Kiran Kamesh, Nutakki Sathvik, Duraiswamy Rama Prabha, Mohammed Noor, Wahab Razia Sultana, Mangalaraja Ramalinga Viswanathan, Manivannan Ajay Vannan

Archives of Acoustics

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2020

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Vol. 45, No. 3

521--540

EN

This research highlights the vibration analysis on worm gears at various conditions of oil using the experimental set up. An experimental rig was developed to facilitate the collection of the vibration signals which consisted of a worm gear box coupled to an AC motor. The four faults were induced in the gear box and the vibration data were collected under full, half and quarter oil conditions. An accelerometer was used to collect the signals and for further analysis of the vibration signals, MATLAB software was used to process the data. Symlet wavelet transform was applied to the raw FFT to compare the features of the data. ANN was implemented to classify various faults and the accuracy is 93.3%.

14

Diagnostics of Transient States in Hydraulic Pump System with Short Time Fourier Transform

Przystupa Krzysztof, Ambrożkiewicz Bartłomiej, Litak Grzegorz

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no. 1

178--183

EN

In hydraulic pump system various states can occur caused by mechanical and physical phenomena. To detect them, the Short Time Fourier Transform (STFT) is applied. This paper will consider an application of STFT to monitor and evaluate hydraulic pump system operation in different states of operation. For measurements of pressure and flow changes in pump, hydraulic tester and Data AcQuisition (DAQ) card was used for evaluation of qualitative and quantitative changes in the system. Results of hydraulic pump’s operation will be shown on Fast Fourier Transform (FFT) charts and STFT spectrograms plots.

15

Problem „przecieku widma” w procesie oceny jakości energii elektrycznej

Kuwałek Piotr

Poznan University of Technology Academic Journals. Electrical Engineering

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2019

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No. 97

63--73

PL

W artykule przedstawiono wyniki symulacji związane ze zjawiskiem „przecieku widma” w procesie oceny jakości energii elektrycznej. Na wstępie artykuł omawia zagadnienia związane z problematyką potrzeby analizy jakości energii elektrycznej oraz związanego z tą analizą zjawiska „przecieku widma”. Kolejno przedstawione zostały analizowane sygnały wraz z ich opisem funkcyjnym. Dla omówionych przebiegów przeprowadzono analizę widmową FFT z wykorzystaniem programu MATLAB. Podczas symulacji zmieniano częstotliwość sygnału badanego w zakresie dopuszczalnych odchyleń częstotliwości napięcia sieci określonych odpowiednią normą. Przy zmianie wspomnianego parametru monitorowano błędy pomiaru zawartości wyższych harmonicznych przy zastosowaniu wybranych okien czasowych. Artykuł kończy się zebraniem wniosków z przeprowadzonej analizy oraz podsumowaniem.

EN

The article presents simulation results related to the phenomenon “spectrum leak” in the process of assessing the quality of electricity. At the beginning, the article discusses issues related to the problem of the need to analyze the quality of electric energy and the phenomenon of "spectrum leakage" associated with this analysis. Subsequently, the analyzed signals were presented along with their functional description. For the discussed runs, FFT spectral analysis was performed using the MATLAB program. During the simulation, the frequency of the tested signal was changed in the range of acceptable voltage deviations of the network defined by the appropriate standard. When changing the frequency, the error of measuring the content of higher harmonics was tested using window function. The article ends with the collection of conclusions from the analysis and the summary.

16

The effect of fuel mixture on engine vibrations

Wróbel Radosław, Łoza Łukasz, Haller Piotr, Włostowski Radosław

Combustion Engines

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2019

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R. 58, nr 2

136--138

EN

In the article, the authors analyze the effect of a fuel mixture (iso-octane, butanol and ethanol) on the generation of engine vibrations. The paper presents the results in the form of frequency response (using the Fast Fourier Transform - FFT) for three mixtures of different proportions. The measurements were made with the use of accelerometers and data acquisition cards, conditioning the received signal. The vibration component, in the form of acceleration, will be subjected to a FFT and presented in graphical form (periodogram). The authors put a special emphasis on a comparative analysis, indicating changes in harmonics, which may be a potential cause of engine degradation.

17

Analiza ograniczania wyższych harmonicznych nieliniowych odbiorników przy wykorzystaniu filtru aktywnego

Kołodziej K.

Zeszyty Naukowe Politechniki Rzeszowskiej. Elektrotechnika

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2018

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z. 37 [297], nr 1

49--62

PL

W artykule przedstawiono wyniki pomiarów związane z ograniczaniem wyższych harmonicznych nieliniowych odbiorników energii elektrycznej przy wykorzystaniu filtru aktywnego. Na wstępie artykuł omawia zagadnienia związane z problematyką filtracji wyższych harmonicznych przy wykorzystaniu filtrów pasywnych i aktywnych w sieciach 0,4 kV. W punkcie tym dokonane zostało krótkie porównanie możliwych typów filtrów oraz ich charakterystycznych cech. Kolejno przedstawione zostały analityczne rozważania dotyczące filtracji wyższych harmonicznych w sieci trójfazowej, czteroprzewodowej przy wykorzystaniu filtru aktywnego, które mają na celu przedstawienie zasady generowania napięć przez filtr aktywny oraz ukazanie złożoności procesu filtracji wyższych harmonicznych. Przy tym przedstawiony i omówiony został schemat wydzielonej części instalacji przemysłowej, która poddana została analizie przy wykorzystaniu analizatorów sieci PM870 a także oscyloskopu cyfrowego z możliwością analizy FFT. W celu zbierania danych z analizatorów wykorzystany został zainstalowany na obiekcie system BMS, który pozwolił na zebranie dużej liczby wartości pomiarowych. Dzięki zebranym danym możliwe było określenie poziomów wartości asymetrii napięć oraz prądów, a także zawartości THD w przebiegach prądów przed oraz za filtrem wyższych harmonicznych. Pozwoliło to na ukazanie realnego oddziaływanie filtru. Poza tym dokonano analizy FFT, na podstawie której można zaobserwować oraz określić udział poszczególnych harmonicznych w tych przebiegach. Analiza ta pozwoliła również na określenie wpływu odzysku energii przy wykorzystaniu prądnic asynchronicznych z układami przekształtnikowymi na jakość energii elektrycznej. Dzięki uzyskanym wynikom pomiarów możliwe było określenie wpływu filtracji aktywnej na daną część sieci, a także udzielenie odpowiedzi na pytanie czy stosowanie tego typu filtracji jest potrzebne, a może wręcz niezbędne. Artykuł kończy się zebraniem wniosków z przeprowadzonej analizy oraz podsumowaniem.

EN

The article presents results of measurements related to the limitation of higher harmonics of a non-linear loads using an active filter. At the beginning the article discusses issues related to the problem of higher harmonics filtration using passive and active filters in 0.4 kV networks. Next, analytical considerations regarding filtration of higher harmonics in a three-phase, four-wire network using an active filter are presented to demonstrate the principle of generating voltage by an active filter and showing the complexity of higher harmonics filtration process. A diagram of a separate part of the industrial installation, which was analyzed using PM870 network analyzers as well as a digital oscilloscope with the function of FFT analysis, was presented and discussed. In order to collect data from the analyzers, the BMS system installed on the site was used, which allowed to collect a large number of measured values. Thanks to the collected data it was possible to determine the levels of voltages and current asymmetry, as well as the THD content in the current waveforms before and after the higher harmonic filter. This allowed to show the real impact of the filter. In addition, FFT analysis was performed, on the basis of which one can observe and determine the contribution of individual harmonics in these runs. This analysis also allowed to determine the outflow of energy recovery using asynchronous generators on the quality of electricity. Thanks to the results obtained, it was possible to determine the impact of active filtration on a given part of the network, as well as to answer the question whether the use of this type of filtration is needed or perhaps even necessary. The article ends with the collection of conclusions from the analysis and the summary.

18

Adaptive technique based on Fast Fourier Transform for selecting the modelled harmonics' orders in Kalman filter

Alshawawreh J.

Przegląd Elektrotechniczny

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2018

|

R. 94, nr 8

95--100

EN

Kalman filter is used widely in harmonics detection in power system, where, the quality of the Kalman filter depends on having accurate predicting values based on a mathematical model of the harmonics in power system. It required an exact knowledge of the harmonics’ orders, and this is difficult especially that in some of power system apparatus the order of harmonics may change during their operation. For that reason an adaptive Kalman filter combined with Fast Fourier Transform FFT is proposed to determine the orders of harmonics that should be modelled in Kalman filter, in order to reduce the error in the estimated signal.

PL

Filtr Kalmana może być wykorzystywany do określania harmonicznych w systemie energetycznym. Dokładność określania harmonicznych zależy od dokładności predykcji. W celu poprawy dokładności adaptacyjny filtr Kalmana jest wspomagany szybką transformatą Fouriera.

19

The influence of the adhesive path width on selected parameters of amplitude-frequency spectrum of ultrasonic surface wave

Kowalczyk J., Ulbrich D., Stępak D.

Journal of Research and Applications in Agricultural Engineering

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2018

|

Vol. 63, nr 4

85--88

EN

During exploitation motor vehicles require a number of maintenance, repair and diagnostic activities. Among all road vehicles, buses deserve special attention. These vehicles are designed to transport more than 9 people with the driver. Contemporary buses are characterized by a significant number of inseparable - adhesive joints. At the production stage the assessment of the quality of adhesive joints can be carried out using destructive and non-destructive methods. The assessment of the quality of adhesive joints of new vehicles can only be carried out using non-destructive methods. Adhesive joints of steel profile-plywood used in modern buses, is a combination difficult to test joints. Such combination can not be examined using classical control techniques. The article proposes not only the use of a surface ultrasonic wave, but also the possibility of analysis of the obtained signals in the frequency domain using the Fast Fourier Transform (FFT). The tests confirmed that within a certain range, this approach allows the assessment of the width of the adhesive path in adhesive joint.

PL

Eksploatowane pojazdy samochodowe wymagają szeregu czynności obsługowych, naprawczych i diagnostycznych. Spośród wszystkich pojazdów drogowych, na szczególną uwagę zasługują autobusy, czyli pojazdy, które są przeznaczone do przewozu więcej niż 9 osób wraz z kierowcą. Współcześnie produkowane autobusy cechują się znaczną liczbą połączeń nierozłącznych – klejowych. Na etapie produkcji, ocena jakości połączeń klejowych może być prowadzona z wykorzystaniem metod niszczących oraz nieniszczących. Ocena jakości połączeń klejowych pojazdów eksploatowanych może być prowadzona jedynie przy wykorzystaniu metod nieniszczących. Połączenie klejowe profil stalowy – sklejka, stosowane w we współczesnych autobusach, to połączenie o niskiej podatności defektoskopowe. Połączenia takiego nie można badać z wykorzystaniem klasycznych technik kontrolnych. W pracy zaproponowano nie tylko wykorzystanie powierzchniowej fali ultradźwiękowej, ale również zaproponowane przeprowadzenie analizy uzyskanych sygnałów w dziedzinie częstotliwości z wykorzystaniem szybkiej transformaty Fouriera (FFT). Przeprowadzone badania potwierdziły, że w określonym zakresie, takie podejście umożliwia ocenę szerokości ścieżki kleju w połączeniu.

20

Diagnostic of malfunction of four stroke marine engine using harmonic components of combustion pressure waveforms

Drewing S., Dereszewski M.

Journal of KONES

|

2018

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Vol. 25, No. 2

97--103

EN

The paper presents results of experimental measurements and analysis of combustion pressure and fuel pressure in high-pressure line before fuel valve. The aim of conducted experiments was detection of failures of high-pressure fuel system. Both pressure signals were recorded simultaneously and subsequently processed using FFT decomposition of obtained wavelets. The idea of comparison of both fuel and gas pressures came after observations of occurrence changes of wavelets form of fuel high pressure, probably caused by malfunction of injector's sprayer. The engine from test bed is very well armoured with sensors, what enable observations of fuel and combustion pressure in real time. Unfortunately, such equipment is very unlike in real objects, what created un idea to find out whether run of combustion pressure wavelet reflects fuel pressure deviations and whether is possible to detect such kind of deviations in way of decomposition of indicated pressure wavelet. Experiment was carried out in laboratory of Gdynia Maritime University, using medium speed diesel engine. Simulation of malfunctions of fuel valve was obtained by installation of specially prepared spraying nozzles. All measurements were carried out at reference load of 75% of MCR (Maximum Continuous Rating). In order to get reliable results and avoid errors due to omitting outer atmospheric conditions, registrations were repeated several times, in days characterized by different temperature and atmospheric pressure.