Diagnosis of Diesel engines

Abstract. Acknowledgements. List of contents. List of figures. List of tables. Chapter one. Introduction. Performance of Diesel Engine. Overview of Diesel Engine Faults. Overall Aim and Objectives. Aim. Objectives. Research Outline. Chapter two. Literature review. Background. Failure Investigation. Condition Monitoring. Vibration Technique. In Cylinder Pressure. Instantaneous Angular Speed. Acoustics (Air-Born Noise). Signal Processing Techniques. Time-domain. Frequency Domain. Time-Frequency Domain. Chapter three. Test rig facility and set up measurement. Diesel Engine Specification. AC Dynamometer. Optical Encoder. Vibration Accelerometer. Pressure Transducer. Condense Microphone. Dynamic Data Acquisition System. Test Rig Set-Up. Chapter four. Characterisation of cylinder pressure signals wthin diesel engine. Introduction. Analysis of Recorder Data. Features in Angular Domain. Load Variation. Speed Variation. Chapter five. Characterisation of vibration waveforms wthin diesel engine. Introduction. Analysis of Recorder Data. Features in Angle Domain. Load Variation. Speed Variation. Features in Frequency Domain. Load Variation. Speed Variation. Chapter six. Characterisation of acoustic waveforms wthin diesel engine. Introduction. Analysis of Recorder Data. Features in Angle Domain. Load Variation. Speed Variation. Futures in Frequency Domain. Load Variation. Speed Variation. Chapter seven. Conclusions and future work. Conclusion. Future Work. Reference.

Because of its high relative efficiency the diesel engine is widely used as a prime power driver for stationary machines such as generators, pumps, compressors, etc, and most types of land and sea vehicles. However, they contribute a significant portion of air pollution and often operate under faulty conditions.

A great deal of condition monitoring research has been conducted recently to attempt to resolve the problems of diesel engines and diagnose faulty operation at an early stage by means of such measurement of engine generated vibration and airborne sound. Such techniques are promising because they need not be intrusive and can provide much information.

This research has been a study of the vibro-acoustics of a diesel engine with the aim of identifying whether such techniques could be used to monitor the fuel quality and hence engine pollutions.

Firstly it investigates the characteristics of vibration in the time, angle and frequency domain under different operating conditions. Then the characteristics of acoustics are also studied under the same conditions. Finally in-cylinder pressures measured using a pressure sensor is examined to connect the analysis results of vibro-acoustics to the engine combustion processes.

Figure 4‎ -1: Raw Cylinder Pressure Signal from a Running Engine at Zero Load Speed 1000 rpm .... 36

Figure 5‎ -1: Raw vibration Signal from a Running Engine at Zero and 350Nm Load Speed 1000rpm 42

This chapter presents the introduction for diesel engine performance, its overview fuel combustion and research outline.

The diesel engine is used almost everywhere on the planet: in transport where it powers most large trucks and buses, for powering industrial and construction equipment, as a generator supplying electricity, as the motor force behind many pumping systems, and so on. Diesel engines used for automotive applications pull well in top gear because the torque they generate does not vary greatly with engine speed [8]. The diesel engine is favoured for boats, ships and marine work generally because it does not use spark ignition which means it does not need a HT electrical supply which is easily damaged by water.

As the performance and characteristics of the engine improve the expectation is that use of the diesel engine will increase. The diesel engine generates the necessary power by burning fuel and converting the energy to mechanical motion [8]. Each cycle of a diesel engine involves intake of air, compression, injection of fuel, combustion, expansion, and the exhausting of the spent fuel-air mixture. The thermal efficiency of the diesel engine is relatively high compared to engines of comparable size, and so it is generally more cost effective to operate.

Modern diesel engines have been developed in parallel with available fuels, and changes in fuel specifications will demand development in engine design. Because the most important economic aspect of operating a diesel power plant is the cost of the fuel, so the higher the price of fuel, the less profitable any power plant is likely to be. Unfortunately the costs of alternative‎fuels‎such‎as‎‘bio-fuels’‎(rapeseed‎oil,‎coconut oil, etc.) is prohibitive. This cost factor far outweighs any positive features such as lower emissions or even zero, impact on global warming.

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Diagnosis of Diesel engines. (2017 m. Kovo 12 d.). https://www.mokslobaze.lt/diagnosis-of-diesel-engines.html Peržiūrėta 2018 m. Kovo 20 d. 23:42