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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.

Thermal loading of diesel engine pistons has increased dramatically in recent years due to applications of various advanced technologies to meet low emission and high power requirements. Control of piston temperatures by cooling of pistons has become one of the determining factors in a successful engine design. The pistons are cooled by oil jets fired at the underside from the crankcase. Any undesirable piston temperature rise may lead to engine seizure because of piston warping. However, if the temperature at the underside of the piston, where oil jet strikes the piston, is above the boiling point of the oil being used, it may contribute to the mist generation. This mist significantly contribute to the non-tail pipe emissions in the form of unburnt hydrocarbons (UBHC's), which has unfortunately not been looked into so seriously, as the current stress of all the automobile manufacturers is on meeting the tail pipe emission legislative limits.

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.