Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
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Item Fault diagnosis of internal combustion engine gearbox using vibration signals based on signal processing techniques(Emerald Group Holdings Ltd., 2020) Kn, R.; Kumar, H.; Gn, K.; Kv, G.Purpose: The purpose of this paper is to study the fault diagnosis of internal combustion (IC) engine gearbox using vibration signals with signal processing and machine learning (ML) techniques. Design/methodology/approach: Vibration signals from the gearbox are acquired for healthy and induced faulty conditions of the gear. In this study, 50% tooth fault and 100% tooth fault are chosen as gear faults in the driver gear. The acquired signals are processed and analyzed using signal processing and ML techniques. Findings: The obtained results show that variation in the amplitude of the crankshaft rotational frequency (CRF) and gear mesh frequency (GMF) for different conditions of the gearbox with various load conditions. ML techniques were also employed in developing the fault diagnosis system using statistical features. J48 decision tree provides better classification accuracy about 85.1852% in identifying gearbox conditions. Practical implications: The proposed approach can be used effectively for fault diagnosis of IC engine gearbox. Spectrum and continuous wavelet transform (CWT) provide better information about gear fault conditions using time–frequency characteristics. Originality/value: In this paper, experiments are conducted on real-time running condition of IC engine gearbox while considering combustion. Eddy current dynamometer is attached to output shaft of the engine for applying load. Spectrum, cepstrum, short-time Fourier transform (STFT) and wavelet analysis are performed. Spectrum, cepstrum and CWT provide better information about gear fault conditions using time–frequency characteristics. ML techniques were used in analyzing classification accuracy of the experimental data to detect the gearbox conditions using various classifiers. Hence, these techniques can be used for detection of faults in the IC engine gearbox and other reciprocating/rotating machineries. © 2020, Emerald Publishing Limited.Item Studying the effects of manifold pressure boosting and EGR on combustion and NOx emission of hydrogen-fueled SI engine(SAGE Publications Ltd, 2023) Pandey, J.K.; Gn, K.Aiming to the global energy insecurity due to extensive dependence on fossil fuels, hydrogen is supposed to provide relief by researchers. However, employed to combustion engines, this green fuel leaves hazardous NOx and limits output due to low volumetric energy content. Hence, improving operating parameters like compression ratio and manifold pressure, and NOx mitigating technique like EGR may prove a boon. Therefore, in the present study, combustion and NOx emission behavior of the SI-engine is studied under variable manifold air pressure (MAP) (up to 130 kPa) and EGR (up to 15%) at compression ratio 14:1. The outcomes shows the flame development increased by 1.24%, while flame propagation is increased by 1.63% by MAP boosting due to increased air and fuel supply. Cylinder pressure and heat-release rate (HRR) are also surged due to the increased fuel supply to maintain excess-air ratio (λ). However, peak cylinder pressure is retarded due to elongated combustion. The exhaust gas temperature (EGT) is increased by 19.4%, while elevated Tmax is observed to shoot up NOx by 40%. Combustion in improved at low EGR due to reduced λ, and also the specific NOx. At higher EGR rate deteriorated combustion due to increased heterogeneity by high dilution, increasing combustion duration, cooling losses and reducing cylinder pressure, Tmax and EGT. A 9.33% and 5.67% increase in CA10 and CA10–90 respectively is observed for 130 kPa at 15% EGR than no EGR. The rapid reduction in oxygen and higher heterogeneity reducing residence time, resulted in rapid drop (33% at N/A to 42.68% at 130 kPa for 15% EGR) in NOx by EGR. The coefficient variation is reduced by boosting MAP but increased severely at higher EGR, which restricts operating EGR rate. © IMechE 2023.