Diesel Engine Lab Report

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RESEARCH ARTICLE OXYGEN ENRICHMENT FOR IMPROVING THE COMBUSTION CHARECTERISTICS OF A DIESEL ENGINE P.BASKAR*, A.SENTHIL KUMAR Faculty, School of Mechanical and Building Sciences, VIT University, Vellore, India *Corresponding Author: pbaskar@vit.ac.in Abstract An investigation on the effects of oxygen enriched air on diesel engine combustion characteristics is carried out under part load and full load conditions. The present investigation focussed on combustion characteristics such as heat release, delay period and combustion duration of a single cylinder four stroke direct injection diesel engine when the intake air is enriched with 21% , 23%,25% and 27% of oxygen by volume. The experimental tests have revealed that increasing oxygen content…show more content…
Introduction Diesel engines are always designed to operate with an excess air in the region of 15% to 40% depending upon the application to find the necessary oxygen for combustion. Therefore the engine size becomes bigger for a given output and the air-fuel mixture will be heterogeneous in nature. One of the main aims of the diesel engine designer is that air-fuel ratio should be as close to stoichiometric as possible while operating at full load at the same time giving a better thermal efficiency and mean effective pressure. To ensure complete combustion even with latest technology the engines must operate in excess air. That is, more air carrying 21% O2 by volume is passed through the intake valve than the chemically required (stoichiometric) for complete combustion and this process ensures that nearly all fuel molecules receive required oxygen for complete combustion. Excess air speeds up the mixing of fuel and air and ensures complete combustion but at the same time excess air wastes heat energy by carrying the heat in the exhaust gases. If sufficient oxygen is not provided to engine during combustion process, complete conversion of carbon and hydrogen is impossible to attain, which leads to particulates and carbon monoxide resulting in increased exhaust…show more content…
[5] studied the effect of partial pressure of oxygen on the indirect injection diesel engine combustion and their research revealed that enriching the intake air with oxygen led to decrease in ignition delay and reduced combustion noise. One of the limitations of using OEA is increased NOx emission, Sekar et al. [6] proved that NOx can be reduced by oxygen enrichment with emulsified diesel fuel with considerable decrease in smoke and particulate matters. Virk et al. [7] tried to reduce NOx emission by retarded injection timing with low levels of OEA by this method NOx levels were kept at the same value as the unenriched-air, while particulates and smoke emissions were reduced by 15 to

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