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Early fault detection and diagnosis for medium-speed diesel engines are important to ensure reliable operation throughout the course of their service. This work presents an investigation of the diesel engine combustion-related fault detection capability of crankshaft torsional vibrations. Proposed methodology state the way of early fault detection in the operating six-cylinder diesel engine. The model of six cylinders DI Diesel engine is developed appropriately. As per the earlier work by the same author the torsional vibration amplitudes are used to superimpose the mass and gas torque. Further mass and gas torque analysis is used to detect fault in the operating engine. The DFT of the measured crankshaft's speed, under steady-state operating conditions at constant load shows significant variation of the amplitude of the lowest major harmonic order. This is valid both for uniform operating and faulty conditions and the lowest harmonic orders may be used to correlate its amplitude to the gas pressure torque and mass torque for a given engine. The amplitudes of the lowest harmonic orders (0.5, 1, and 1.5) of the gas pressure torque and mass torque are used to map the fault. A method capable to detect faulty cylinder of operating Kirloskar diesel engine of SL90 Engine-SL8800TA type is developed, based on the phases of the lowest three harmonic orders.

Non-traditional process like wire electro-discharge machining (WEDM) is found to show a promise for machining metal matrix composites (MMCs). However, the machining information for the difficult-to-machine particle-reinforced material is inadequate. This paper is focused on experimental investigation to examine the effect of electrical as well as non-electrical machining parameters on performance in wire electro-discharge machining of metal matrix composites (Al/SiCp). Taguchi orthogonal arrays were employed to study the effects of combinations of voltage, current, pulse on-time, off-time, and wire speed and wire tension on kerf width and cutting speed. Voltage, current, and on-time were found to have significant effect on cutting speed and kerf width. The optimum machining parameter combinations were obtained for cutting speed and kerf width separately. Further, multi-objective optimization was done using Taguchi-Grey relational analysis. The process has been improved with the aid of Grey relational analysis and Taguchi orthogonal array. The results have been verified with confirmation experiments.

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In this study, wire electrical discharge machining of aluminium matrix composites has been experimentally investigated. A metal matrix composite Al/Al2O3p/10% has been machined at various combinations of machining parameters such as pulse on-time, off-time, wire speed and wire tension. Empirical models have been developed to predict the cutting rate, surface roughness and kerf width of the machined composite material. The models were developed by using the technique of response surface methodology. The experiments were conducted by using carefully planned response surface design matrix (central composite design). The model predictions are in good agreement with the experimental results. The R2 values of the proposed cutting rate, and kerf width models are above 0.99 and 0.98 respectively, where as it is 0.95 for the surface roughness model. The pulse on-time was found to influence cutting rate and surface finish significantly. Kerf width was significantly affected by pulse on-time, off-time, wire speed, and wire tension. In addition, a model was developed to correlate the multiple performance characteristic called as grey relational grade and the process parameters. Thus, a new combination of response surface method and grey relational analysis is proposed. The grey relational grade was significantly affected by pulse on-time and off-time time. The R2 value for the grey relational grade model was 0.94. Optimal parameter setting was determined for the multiple performance characteristic. The improvement in cutting rate was more than 100% compared to the ‘0’ level experiments, with reasonably smooth surfaces and narrow kerf width.