EXPERIMENTAL ANALYSIS OF OPTIMAL GEOMETRY FOR EXHAUST MANIFOLD OF MULTI-CYLINDER SI ENGINE FOR OPTIMUM PERFORMANCE

摘要

In internal combustion engines, Brake specific fuel consumption is direct measure of fuel economy of engine whereas volumetric efficiency is one of the prime factors in determining how much power output an engine can generate as compared to its capacity. Exhaust velocity & back pressure are the parameters on which emissions from the engines would depend. The purpose of this research work is to investigate which can be the best geometry for exhaust manifold of the multi-cylinder SI engine. The research work is concentrated on the experimental investigation of 4 different models of exhaust manifold and conclude on best possible design of exhaust of the manifold. Physical models of the two systems were manufactured exhaustive experiments were carried out on them. The analysis has been carried out on two designs an existing one and a modified one. It was observed that the volumetric efficiency improved drastically upon modification in exhaust geometry. Later on both these models were modified by attaching a reducer at its outlet and similar experiments were carried upon them. Attachment of reducer leads to drastic reduction in BSFC. The scope of the research of this work has been stretched to investigate whether all the design modifications which were considered has any impact on the other factors like exhaust velocity, back pressure, exhaust temperature, mechanical efficiency etc.