Abstract

In dealing with car repairs and troubleshooting, mechanics are those who can help to fix it. But most of the time, we would not have enough time to get the mechanic and therefore we need instant help and solution. So it is believed that the use of expert system can be beneficial in this situation by giving instant guidance. An expert system is a structure that employs human knowledge captured in a computer to solve problem that ordinarily require human expertise. Expert system seeks and utilizes relevant information from their human users and from available knowledge base in order to make recommendations. In this paper we have introduced the frame work for developing Expert System for Car Maintenance and Troubleshooting, which is based on the methodology that has been adopted from several existing methodologies for different applications especially in the field of computer science, software engineering, knowledge engineering and multimedia, since this expert system will be an integration of these technologies.

Abstract

On-line tool wear estimation in turning is essential for on-line cutting process optimization. In this work, cutting force measurement is used for a reliable on-line flank wear estimation and tool life monitoring. Models for flank wear will be obtained as a function of machining parameters and dynamic cutting forces. The coefficients for flank wear models are obtained by using the experimental results. Then the non-linear dynamic models obtained are calibrated with the actual conditions. These developed models will be used for the simulation of flank wear and using control variable such as cutting speed; the flank wear will be controlled. For model validation, the flank wear is estimated using a non-linear model. In the present work, an attempt has been made to control the flank wear during turning of on-line cutting process using the Neural network based on self-tuning of PID controller approaches. This approach treats the material as dynamic system and involves developing state space models from available material behavior model.

The evaluation of performance criteria can be compared for both approaches of PI controller and Neural network based on self-tuning of PID controller. Simulation studies are carried-out for the non-linear system using MATLAB software.

Abstract

Diesel engines are the best prime movers with substantial inherent energy transfer to the coolant. To minimize this heat transfer to the coolant, low heat rejection (LHR) concept was developed. At the same time, drawbacks were also encountered because of the very high combustion chamber temperatures in LHR engines. Heavy exhaust blow-down energy and high Oxides of Nitrogen (NOx) emissions were two among them, which has lead to decrease in thermal efficiency and inability to achieve legislative emission levels. To realize the advantages of LHR diesel engine, the cycle calculations were formulated and developed under numerical simulation. The parametric studies were carried out with closer duration of each crank angle degree. In the engine cycle calculations the internal Exhaust Gas Recirculation (iEGR) and extended expansion processes were coupled to minimize the drawbacks of LHR engine. The iEGR is accomplished with the secondary exhaust valve opening during suction stroke and the extended expansion by incorporating the Miller cycle by delaying the IVC timing.  The heat release is calculated using preparation rate and reaction rate, considering two-zone combustion.  The total heat transfer is calculated using Annand’s combined heat transfer model.  During combustion, chemical equilibrium of oxygen and nitrogen were determined to calculate the nitric oxide formation rate, assuming ZELDOVICH mechanism. The results of the numerical simulation were validated by conducting experiments in a Conventional and as well as LHR turbocharged four cylinder DI diesel engine.  Modification of gas exchange has resulted in decrease in nitric oxide emissions along with a considerable improvement in thermal efficiency under LHR condition.

Abstract

Effect of adding oxygenates on the performance, emission and combustion characteristics on a direct injection diesel engine fuelled with cotton seed oil (CSO) was investigated. Diethyl ether (DEE) was used as oxygenate. A single cylinder water-cooled direct injection diesel engine developing a power output of 5.2kW at 1500 rev/min was used. Quantity of oxygenate was varied from 10 % to 30 % to find the optimum blend performance. Brake thermal efficiency improves from 28 % with neat CSO to a maximum of 29.5 % with 30 % of DEE. Smoke value is 3.9 BSU with neat CSO, 3.6 BSU with 30 % of DEE and 3.4 BSU with diesel. Hydrocarbon and carbon monoxide emissions are also less with DEE. Peak pressure and maximum rate of pressure are found to be higher with DEE and CSO than neat CSO. On the whole, it is concluded that adding small quantities of oxygenates (DEE) can significantly improve the performance of a cottonseed oil fuelled diesel engine.

Abstract

In direct injection (DI) diesel engines the fuel spray characteristics have high influence on engine performance as well as exhaust gas emissions. The fuel spray orientation plays very important role in fuel air mixing. A single cylinder four stroke DI diesel engine with fuel injector having multi-hole nozzle injector is considered for the analysis and a computational fluid dynamics (CFD) code, STAR-CD is used for the simulation. In the present study, various fuel spray orientations are considered for the analysis. It is shown that there is an optimal orientation for the fuel spray and the wall wetting area influences on the emission formations.  Results are reported for distribution of fuel spray for different spray orientations and discussions are made with the profiles of pressure, temperature, number of droplet parcels, turbulent kinetic energy (TKE)., and exhaust gas emissions.

Abstract

This work has the objective of quantifying the influence of the friction stir welding (FSW) technique on the mechanical properties and microstructure of an aluminium alloy 6082. FSW is a solid-state welding process developed and patented by the TWI in 1991. It emerged as a welding technique to be used for various alloys that are difficult to join with conventional techniques. The process was developed initially for aluminium alloys, but since then FSW was found suitable for joining a large number of materials catering to wide range of applications.

In the present work, sheets of aluminium alloys were friction stir-welded under various combinations of rotational and translational speeds. Investigation of the FSW parameters was carried out through varying the revolutions per minute at which the tool rotates and the feed rate at which the work piece proceeds. This work reports the results of various tests such as Vickers micro-hardness and tensile tests. And also the influence of weld parameters was discussed. The results indicate that the weld strength and the microstructure evolved during FSW are sensitive to the rotational and translational speeds. It was observed that the grain refinement is influenced by rotational speed and also by translational speed. Thus the choice of process parameters especially the rotational speed has a significant effect on the control and optimization of the process.

Abstract

Jatropha oil is one of the vegetable oils that haves potential for use as fuels for diesel engines. But at room temperature (30—320C) Jatropha has a viscosity about 10 times higher than that of diesel. To lower viscosity to the level of diesel’s viscosity, a heating temperature of at least 1800C is needed. At this temperature, there is a concern that the close-fitting parts of the injection system might be affected. This study focused on finding out the effects of preheating of fuel on the performance and emissions of a DI diesel engine.  Results show that preheating of Jatropha oil lowered emissions compared to Jatropha oil. However, heating is necessary for smooth flow and to avoid fuel filter clogging. Both can be achieved by heating Jatropha oil to 1800C. Over  the  entire  load  range,  preheated Jatropha oil combustion  produced  lower  CO  and  HC  emissions  that were  30 %  and  25 %   compared  to Jatropha oil. NOX emission is higher about 5 % in the case of preheated oil compared to Jatropha oil.