Fault Detection and Diagnosis in Diesel Engine Using Acoustic Emission (AE)

• Diesel engines are a kind of power source widely used in many fields. • One of the biggest problems facing machinery today is the high cost of maintenance of diesel engine because the downtime of the engine is expensive. • Not only does a fault reduce the performance of the engine but also causes secondary damage to other parts of the engine. • The use of acoustic emission offers non-intrusive tool for engine monitorin

Diesel Engine Injector Faults Detection Using Acoustic Emissions Technique

This study focuses on investigation of the method of identifying injector faults in a JCB 444T2 diesel engine using acoustic emission (AE) technique. Different kinds of injector faults were seeded in the four-cylinder, four-stroke, and turbo-engine. Then, faulty injectors are tested to evaluate AE based injection fault detection. The AE signals recorded from the tests were processed in the angular, frequency and joint angular-frequency domain. The results from joint angular-frequency analysis have shown that AE can clearly monitor the changes in the combustion process due to its high signal to noise ratio, where other vibro-acoustic sources have little influence. Using features in the AE signal, faults of injector can be identified during the operation of the engine

Fault Detection and Diagnosis in Heavy Duty Diesel Engines Using Acoustic Emission

A condition monitoring program applied to diesel engines, improves safety, productivity, increases serviceability and reduces maintenance costs. Investigation of a novel condition monitoring systems for diesel engine is attracting considerable attention due to both the increasing demands placed upon engine components and the limitations of conventional techniques. This thesis documents research conducted to assess the monitoring capabilities used acoustic emission (AE) analysis. It focuses on the possibility of using AE signals to monitor the fuel injector and oil condition. A series of experiments were performed on a JCB, four-stroke diesel engine. Tests under healthy operating conditions developed a detailed understanding of typical acoustic emission generation in terms of both the source mechanisms and the characteristics of the resulting activity. This was supplemented by specific tests to investigate possible acoustic emission generation due to the piston slap and friction. The effect of faults on the injector waveform was investigated using the injection system and at one sensor location. To overcome the reflections and injection system configuration effects the method of acoustic emission impedance was used. This enabled the injector signal to be successfully extracted and clearly shows its capability for detecting even minor combustion deviations between engine cylinders. Comparison between signals and measurement of the oil condition showed both provided useful information about the lubrication processes. Simulation and experimental work have demonstrated the capability of this technique to detect lubrication related faults and irregular lubrication variability between the engine's cylinders. A review of the AE sources in diesel engines and how to represent the AE signals generated is presented. Three analysis methods were used: time-domain analysis using parameters such as Root Mean Square (RMS), variance, mean and kurtosis; frequency-domain analysis which relied on the amplitudes of the frequency components of the measured signals; and time-frequency domain analysis extracting features so that the energy content of the signals and the frequency components were localized simultaneously. In this work, data has been obtained from tests on a diesel engine, where the engine load, speed, temperature and the oil lubrication type were changed. The monitored signal and its difference from that obtained for normal engine conditions was noted as a fault signature that could be used for fault detection and diagnosis

Detection of diesel engine valve clearance by acoustic emission.

This paper investigated, using experimental method, the suitability of acoustic emission (AE) technique for the condition monitoring of diesel engine valve faults. The clearance fault was adjusted experimentally in an exhaust valve and successfully detected and diagnosed in a Ford FSD 425 four-cylinder, four-stroke, in-line OHV, direct injection diesel engine. The effect of faulty exhaust valve clearance on engine performance was monitored and the difference between the healthy and faulty engine was observed from the recorded AE signals. The measured results from this technique show that using only time domain and frequency domain analysis of acoustic emission signals can give a superior measure of engine condition. This concludes that acoustic emission is a powerful and reliable method of detection and diagnosis of the faults in diesel engines and this is considered to be a unique approach to condition monitoring of valve performance

Detection of Diesel Engine Injector Faults Using Acoustic Emissions

This study investigated the method of identifying injector faults in a JCB 444T2 diesel engine using acoustic emission (AE) technique. Different kinds of injector faults were seeded in the four-cylinder, four-stroke, and turbo-engine. The AE signals recorded from the tests were processed in the angular domain, frequency and joint angular-frequency domain. The results showed that AE could clearly monitor the combustion process of diesel engine because high frequency AE signal measured from engine cylinder head has very high signal-to-noise ratio. Using features in the AE signal, faults of injector can be identified during the operation of the engine

The Analysis of Acoustic Emission Signals from the Cylinder Head of a Diesel Engine for Fault Detection

There are many acoustic emission (AE) sources in a diesel engine. During an engine cycle, fuel injection, onset of combustion, valve impacts and piston slaps all produce AE effects. Because these events happen around the top dead centre, it is difficult to separate them for the purpose of combustion monitoring. This study focuses on characterising AE signals measured on the cylinder head of a diesel engine for injection fault diagnosis. Firstly, AE signals are analysed to understand AE signals in association with engine operating conditions and sensor placement. Then, faulty injectors are tested to evaluate AE based injection fault detection. The results from joint angular and frequency analysis has shown that AE can clearly monitor the changes in the combustion process due to its high signal to noise ratio in the high frequency range from 10kHz to 45kHz where other vibro-acoustic sources have little influence

Diesel Engine Valve Clearance Detection Using Acoustic Emission

This paper investigated, using experimental method, the suitability of acoustic emission (AE) technique for the condition monitoring of diesel engine valve faults. The clearance fault was adjusted experimentally in an exhaust valve and successfully detected and diagnosed in a Ford FSD 425 four-cylinder, four-stroke, in-line OHV, direct injection diesel engine. The effect of faulty exhaust valve clearance on engine performance was monitored and the difference between the healthy and faulty engine was observed from the recorded AE signals. The measured results fromthis technique show that using only time domain and frequency domain analysis of acoustic emission signals can give a superior measure of engine condition. This concludes that acoustic emission is a powerful and reliable method of detection and diagnosis of the faults in diesel engines and this is considered to be a unique approach to condition monitoring of valve performance

Online Monitoring of Engine Oil Quality Based on AE Signal Analysis

This paper studies online condition monitoring of engine oil by analysing the acoustic emission (AE) signals. The AE signals were measured using an AE sensor mounted on the thrust side between second and third cylinders in a four cylinder diesel engine. The signals were then filtered and transformed to the frequency domain, where the amplitudes of the different frequency components of the AE waveforms were analysed and compared to the AE baseline signatures. The mean amplitudes of the spectral components in the frequency band 10kHz to 50kHz were found linearly proportional to the engine speed and load. It was also found that the RMS values of this frequency band were affected by the oil viscosity. These results show that it is possible to use AE measurement to predict the quality of lubrication

Lubricating Oil Condition Monitoring Using Acoustic Emission

This study has been conducted aiming at engine oil condition monitoring and quality evaluation by analyzing the engine acoustic emission signals. The acoustic emission signals were measured using an acoustic emission sensor mounted on the engine block

Detection of Diesel Engine Injector Faults Using Acoustic Emissions

Early detection of diesel engine faults is essential in order to take early correction actions and avoid costly repair. Injection faults due to defects in a fuel pump, fuel lines and injectors affect the power of the engine, increase the polluting particles in the exhausted gas and reduce the life cycle of the engine. High frequency AE signal measured from engine cylinder head has a very high signal-to-noise ratio and can be used to monitor the condition of engines. Three injection faults were seeded (injector pressure decrease, increase and injector blocked) in a four-stroke, four-cylinder diesel engine in the experimental study to investigate the potential of AE diagnostic technology