Effect of Vegetable De Oiled Cake-Diesel Blends on Diesel Engine

Abstract

Alternative sources for petroleum fuels have been the prime concern of most of the environmentalists. It is also a concern for economists due to the depletable nature of the fossil fuel. Vegetable oils are considered as good alternatives to diesel as their properties are close to diesel. At present biodiesel is commercially produced from the vegetable oils by esterification processes. Since most of these oils are edible, its cost restricts the usage. The de oiled cakes after crushing the seeds contains around 2% of oil with less fatty materials is aimed in this study. The fuel is prepared by adding various dry de oiled cake powders (coconut, neem, ground nut and gingili) at different proportions ranging from 3 to 25% by weight with diesel. Experimental results reveal that, the fuel has the potential to reduce smoke, CO emissions simultaneously along with marginal increase in brake thermal efficiency. The combustion characteristic of each fuel is analysed and recorded. The petroleum based diesel fuel needs to be substituted with alternate fuel to meet the energy demands in the future for developing countries. The fossil fuels are depleting drastically which increases the demand in the international market that affects the economy of the developing countries like India. Thus an alternate energy source has to be identified to overcome the problems with the petroleum based diesel fuel. One such energy source is fuel derived from vegetable oil that is bio diesel. Many bio diesels in the form of esters are being experimented to suit the diesel engine without any major engine modification. Pure coconut oil usage in diesel engine shows lesser smoke, carbon monoxide (CO), hydrocarbon (HC) emissions compared to diesel fuel since it has oxygen molecules which results in enhanced oxidation (1). With pure coconut oil and diesel fuel blends in an automotive DI diesel engine increase in brake power and net heat release rate with a reduction in emissions such as HC, CO, NOx, smoke are reported for coconut oil in the fuel blend. The increase in brake power is expected due to larger fuel droplets and oxygen content in coconut oil, which contribute to better combustion. When the coconut oil in the fuel is increased above 20 % decrease in performance was reported which is attributed to lower calorific value, with a reduction in emissions (2). Coconut oil methyl ester COME was investigated by a couple of authors in a variable speed DI diesel engine and their results show that COME gives maximum torque occurs at lower speed compared to diesel and the emissions are lowest for COME compared to diesel and pure coconut oil (3,4). COME was compared with palm and rapeseed oil biodiesel and the results show that the