Effect of Injection Pressure On Performance Parameters And Combustion Characteristics Of High Grade Low Heat Rejection Diesel Engine With Preheated Cotton Seed Biodiesel

ABSTRACT Investigations were carried out on engine with low heat rejection combustion (LHR) chamber with different operating conditions (normal temperature and preheated temperature) of the cotton seed biodiesel with varied injector opening pressure. Preheated temperature is temperature at which viscosity of biodiesel is matched to that of diesel fuel. The concept of LHR engine is to minimize the heat loss to the coolant by providing thermal resistance to heat flow to the coolant. The LHR engine consisted of air gap insulated piston with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head. Vegetable oils are important substitutes for diesel fuel, as their properties are comparable to diesel fuel and also they are renewable in nature. However, drawbacks associated with vegetable oils of high viscosity and low volatility need to be converted into biodiesel. However drawbacks associated with biodiesel of moderate viscosity and low volatility which cause combustion problems in CI engines, call for engine with hot combustion chamber. Performance of brake thermal efficiency, exhaust gas temperature, brake specific energy consumption, coolant load and volumetric efficiency were evaluated at full load operation of the engine. Combustion characteristics of peak pressure, maximum rate of pressure rise and time of occurrence of peak pressure were determined by Piezo electric pressure transducer, TDC (top dead center) and special pressure- crank angle software package at full load operation of the engine. Comparative studies were made for engine with LHR combustion chamber and CE at manufacturer's recommended injection timing (27o bTDC) with biodiesel operation. Engine with LHR combustion chamber with biodiesel showed improved performance and combustion characteristics cat 27o bTDC over CE.