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The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from vegetable oils present promising “greener” substitutes for fossil fuels. Vegetable oils due to their agricultural origin are able to reduce net CO2 emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported, which are because of their higher viscosity and low volatility compared to mineral diesel. In the present research, experiments were designed to study the effect of reducing Jatropha oil's viscosity by blending with mineral diesel, thereby eliminating its effect on combustion characteristics of the engine. In the present experimental research, vegetable oil (Jatropha Curcus) was used as substitute fuel.

The Homogeneous charge compression ignition (HCCI) is the third alternative for the combustion in the reciprocating engine. HCCI a hybrid of well-known spark ignition (SI) and compression ignition (CI) engine concepts and has potential of combining the best features of both. A two cylinder, four stroke, direct injection diesel engine was modified to operate one cylinder on the compression ignition by detonation of homogeneous mixture of ethanol and air. The homogeneous mixture of the charge is prepared by port injection of ethanol in the preheated Intake air. This study presents results of experimental investigations of HCCI combustion of ethanol at intake air temperature of 120°C and at different air-fuel ratios. In this paper, the combustion parameters, pressure time history, rate of pressure rise, rate of heat release, mean temperature history in the combustion chamber is analyzed and discussed.

The methyl esters of vegetable oils, known as biodiesel are becoming increasingly popular because of their low environmental impact and potential as a green alternative fuel for diesel engine and they would not require significant modification of existing engine hardware. Methyl ester of rice bran oil (ROME) is derived through transesterification process. Previous research has shown that ROME has comparable performance, lower bsfc in comparison to diesel. There was reduction in the emissions of CO, HC, and smoke but NOx emissions increased. Experimental investigations have been carried out to examine the combustion characteristics in a direct injection transportation diesel engine running with diesel, and 20% blend of rice bran methyl ester with diesel.

This paper deals with the evaluation of steel cap pistons for up-gradation of diesel electric locomotives for Indian Railways. These engines are four stroke, medium speed compression ignition engines (CR 12.5: 1) with output of 121 kW per cylinder on series 1 and 167 kW per cylinder on series 2. The series 1 engine uses single piece aluminum pistons, with rating of 0.295 kW/cm2 of piston crown area. A higher version of the series 1 engine with higher fuel efficiency and improvement in lube oil consumption was developed. As part of this improvement program, a composite steel cap piston with forged aluminum skirt was used. The whole engine up-gradation kit including the higher capacity turbocharger, higher fuel delivery pressure fuel pump, modified cam shaft, larger after-cooler along with the steel cap piston were evaluated for performance.

This experimental study was undertaken to investigate the use of vegetable oil derivatives to substitute mineral diesel fuel. Straight vegetable oils pose some problems like injector coking, carbon deposits etc., when used as a fuel in an engine. These problems are due to high viscosity, low volatility and polyunsaturated character of vegetable oils. Transesterified vegetable oil derivative called “biodiesel” appear to be most convenient way of utilizing vegetable oil as a substitute fuel in diesel engines. In present investigation, rice bran oil (non-edible) was transesterified to methyl ester and reaction conditions for transeterifcation process for rice bran oil were optimized. Various properties like viscosity, density, flash point of the biodiesel thus prepared are comparable to diesel and found to be in acceptable range as per ASTM norms (ASTM D6751). Experimental investigations were carried out on a four stroke, four cylinders, transportation DI diesel engine.

Increased environmental awareness and depletion of fossil fuel resources are driving industry to develop alternative fuels that are environmentally more acceptable. Vegetable oils are potential alternative fuels. Vegetable oils in India are produced from numerous oil-seed crops. While all vegetable oils have high energy content, most require some processing to ensure safe usage in internal combustion engines. Most detrimental properties of oils are its high viscosity, low volatility and polyunsaturated character. The most widely used method is to convert vegetable oils into biodiesel. Biodiesel fuels are primary esters, which are produced by transesterifcation of vegetable oils. Several vegetable oil esters have been investigated so far in different parts of the world and found suitable to be used in diesel engines.