This paper focuses on the experimental investigation of machining parameters such as cutting speed, feed rate and depth of cut influence over surface roughness parameters (Ra, Ry and Rt) during turning AISI 4340 steel. Further, in order to achieve smaller surface roughness parameter values, the machining parameters are optimized using Taguchi's technique Signal-to-Noise ratio (S/N ratio). Analysis of Variance (ANOVA) is performed to determine the most contributing factor that influences the surface roughness parameters. It is observed that the feed rate is the most significant factor contributing by 70.50%, depth of cut by 18.54% and cutting speed by 9.15%. From the optimum condition obtained, a confirmation experiment is performed and the results obtained shows that the surface roughness parameter values are reduced by 31.63% than the designed experimental values.

Exhaust gas re-circulation is a method used in compression ignition engines to control and reduce NOx emission. These emissions are controlled by reducing the oxygen concentration inside the cylinder and thereby reducing the flame temperature of the charge mixture inside the combustion chamber. In the present investigation, experiments were performed to study the effect of exhaust gas re-circulation on performance and emission characteristics in a four stroke single cylinder, water cooled and constant speed diesel engine. The experiments were performed to study the performance and emissions for different exhaust gas re-circulation ratios of the engine. Performance parameters such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, total fuel consumption and emission parameters such as oxides of nitrogen, unburned hydrocarbons, carbon monoxide, carbon dioxide and smoke opacity were measured. Reductions in NOx and CO2 were observed but other emissions like HC, CO, and smoke opacity were found to have increased with the usage of exhaust gas re-circulation. The 15% exhaust gas re-circulation was found optimum for the engine in the aspects of performance and emission.

In this study, the performance and exhaust emissions of a biodiesel fuelled low heat rejection (LHR) direct injection Diesel engine have been investigated experimentally and compared with the results of standard diesel engine without any coatings. Piston, cylinder head, exhaust and inlet valve of test engine were coated with 0.5 mm thickness of zirconia through plasma spray method. Biodiesel used in the testing was prepared from rice bran oil through transesterification process.

In recent times, increased consumption of fossil fuels due to overpopulation, increasing energy demand have resulted in global warming and climate changes due to the emission of greenhouse gases from these fuels. To compensate for the requirement of fossil fuel, renewable biofuels especially, biodiesel are preferred for satisfying the energy demand. Since biodiesel from edible feedstocks is deemed against "food vs. fuel" policies, first-generation biofuels are not regarded as suitable and sustainable, inspite of growing energy demand. Following this, Second generation biodiesel production from lingo-cellulosic-based feedstocks is the least recommended because of their meticulous procedures and high capital investments. Considering these setbacks, edible feedstocks have been replaced with microbial feedstocks, which are later on used for extracting oil and then transesterified into biodiesel. Even though biodiesel from microbes have their setbacks, they are widely appreciated due to their merits which include short life span, ability to grow on multiple environments and ability to remediate different polluted environmental conditions. Presently, this paper focuses on summarizing the production of biodiesel from various microbial species.

Fossil fuel resources are decreasing daily and attracted researchers to focus on alternative fuels. Biofuels (renewable fuels) are attracting attention worldwide as blending components or direct replacements for petroleum based fuel in vehicle engines. Moreover, Biofuel will also provide rich biomass and nutrients to the soil. This paper presents the results of performance and emission analysis carried out in a naturally aspirated unmodified diesel engine fuelled with preheated crude palm oil (PCPO) and its blends with diesel. It was observed that preheated CPO reduces exhaust emissions such as CO and HC as compared to ordinary diesel (OD). This is mainly attributed to the fact that preheating of crude palm oil reduces its viscosity to the level of ordinary diesel fuel, which improves the fuel spray and atomization characteristics and produces better combustion.