Combustion of Jatropha curcas Oil, Methyl Esters and Blends with Diesel or Ethanol in a CI Engine

Abstract

Renewable fuels have advantages in terms of energy recycling, biodegradability, energy security, environmental concerns, foreign exchange savings and socio-economic issues compared to fossil fuels. The high viscosity of vegetable oils leads to problem in pumping and spraying characteristics. The inefficient mixing of vegetable oils with air contributes to incomplete combustion. The best way to use vegetable oils as fuel in compression ignition engines is to convert them into biodiesel. Biodiesel is a methyl or ethyl ester of fatty acids made from vegetable oils (both edible and non-edible) and animal fat. The main resources for biodiesel production can be non-edible oils obtained from plant species, such as Pongamia pinnata (Honge oil), Jatropha curcas (Ratanjyot), Oryza sativa (Rice bran oil) and Calophyllum inophyllum (Nagchampa). Biodiesel can be used in its pure form or can be blended with diesel to form different blends. It can be used in compression ignition (CI) engines with very little or no engine modification as it has properties similar to mineral diesel. This paper presents comprehensive results of investigations carried out by us on the use of Jatropha oil, Jatropha oil methyl ester and blends with diesel or ethanol in a single-cylinder, four stroke, direct-injection, CI engines. Comparative measures of brake thermal efficiency, smoke opacity, HC, CO, NOX, ignition delay, combustion duration and heat release rates with diesel fuel have also been presented and discussed.