An experimental study was carried out to compare the parameters—Brake Power (BP), Specific Fuel Consumption (SFC), Brake Thermal Efficiency (BTE) and Exhaust Gas Temperature (EGT)—of different compositions of biodiesel and conventional diesel. Tests were performed on a single cylinder direct injection engine operating on diesel fuel, Karanja biodiesel and blends of diesel and Karanja biodiesel in proportions of 100/0%, 80/20%, 60/40% and 40/60% (v/v). The design approach based on Taguchi's orthogonal arrays was adopted for carrying out experiments. The results show that Karanja biodiesel can be conveniently used as a diesel substitute in Compression Ignition (CI) engine. There was an increase in BTE, BP and a reduction in SFC for Karanja biodiesel blends with diesel. An Artificial Neural Network (ANN) model was also prepared by using some experimental data for training and standard back-propagation algorithm for the CI engine.

The fast depleting nature of petroleum products and pollution problems related to them force us to find suitable alternative fuels for use in CI engines. In view of this, the use of vegetable oil is one of the promising alternatives because it has several advantages—renewable, environment-friendly and produced easily in rural and remote areas, where there is a need for energy for lighting and other agricultural purposes (Harrington, 1986; Kloptenstem, 1988; and Masjuki, 1993). Therefore, in recent years, many efforts have been made by several researchers to use vegetable oils as fuel in heat engines (Masjuki and Sohif, 1991). The use of non-edible vegetable oils as compared to edible oils is most significant because of the great demand of edible oils and high cost.

In the present era of energy-environment crises, it is important to identify renewable and alternative clean combustible fuels. One of the significant ways to solve the problems related to petroleum fuels is the use of vegetable-based fuels known as biodiesel. Biodiesel is an alternative fuel obtained from vegetable oils by modifying their molecular structure through the transesterification process (Agarwal, 2005). In the transesterification process, reaction of a triglyceride and an alcohol is done in the presence of a catalyst to produce glycerol and ester. Methyl or ethyl esters obtained from vegetable oils are termed as biodiesel. They have several advantages and can be conveniently used in any existing design of a CI engine without any significant modification. The use of vegetable oils as fuel is not a recent discovery in the field of fuels. Rudolf Diesel, the German inventor, presented a diesel engine operated by peanut oil at the world exhibition in Paris in 1900. But due to compactness and abundant availability of petroleum-based fuel, vegetable oils were neglected as fuels in heat engines. Biodiesel can be produced from a wide variety of plant oils, both edible and non-edible. Biodiesel, in most of the developed countries like the US, are being produced from sunflower, peanut, palm and several other feed stocks. These feed stocks are edible in the Indian context, therefore, in the developing countries such as India, it is desirable to produce biodiesel from non-edible oils which can be extensively grown in the waste and barren lands of the country. The reported non-edible oils available in India are Karanja, Jatropha, rubber seed, Simarouba, etc. (Planning Commission, 2003). Most of the literature mainly deals with research in methyl ester (Canakci and Van Gerpen, 2003; Ramadhas et al., 2005; Meher et al., 2006; and Veljkovic et al., 2006).

Mechanical Engineering Journal, Performance Evaluation of Karanja Biodiesel, Brake Thermal Efficiency, Petroleum Products, Energy-Environment Crises, Transesterification Process, Vegetable Oils, Process Optimization, Neural Networks, Design Parameters, Taguchi Methodology.