Ecology, Environment and Conservation Paper

CONTROL OF POLLUTION LEVELS IN INSULATED DIESEL ENGINE

K. Laxmi, K.N.V. Sree Devi and M.V.S. Murali Krishna

Abstract

Vegetable oils and alcohols are important substitutes for diesel fuel as they are renewable in nature. However drawbacks associated with vegetable oils (high viscosity and low volatility) and alcohols (low cetane number) call for engine with hot combustion chamber with its significant characteristics of higher operating temperature, maximum heat release, higher brake thermal efficiency (BTE) and ability to handle the lower calorific value fuel. Butanol was inducted into the engine through a variable jet carburetor, installed at the inlet manifold of the engine at different percentages of crude vegetable oil (tamarind oil blended with 15% diethyl ether (DEE)) at full load operation on mass basis. The control of pollution levels was achieved by change of engine configuration and fuel composition. Crude vegetable oil was injected at near end of compression stroke. Exhaust emissions of particulate emissions, nitrogen oxide levels and aldehyde levels were determined with insulated engine, consisting of ceramic coated (thickness 500 microns) cylinder head and ceramic coated cylinder liner with mixture of carbureted butanol and crude vegetable oil with varied injector opening pressure and at recommended injection timing of 27obTDC (before top dead centre). Comparative studies were made with data of neat diesel/neat vegetable oil operation at similar operating conditions. Particulate emissions and nitrogen oxide (NOx) levels were measured at full load operation with sophisticated analyzers. Aldehydes were measured by the 2,4, dinitrophenyl hydrazine (DNPH) method. The maximum induction of butanol was 55% at recommended injection timing With maximum induction of butanol, at an injector opening pressure of 190 bar, at recommended injection timing, insulted engine decreased particulate emissions by 32%, nitrogen oxide (NOx) emissions by 18%, increased formaldehyde emissions and acetaldehyde emissions drastically, when compared with neat diesel operation on conventional engine.