Effect of EGR on Performance of CI Engine with Diesel and Cotton Seed Oil as Fuels

Automobile emission is one of the major problems in the environment. Engine emits the carbon monoxide (CO), unburnt hydrocarbon (HC) and smoke density, etc and causing a variety of health and environmental problems at the locations far from their emissions source. These problems include ground level ozone and smog, which are created in the atmosphere. Motor vehicle emissions contributes to air pollution and are a major source in the creation of smog in some large cities. The health risks of air pollution are extremely serious. In general, an exhaust gas is a gas emitted through a combustion process. The exhaust gas is actually a combination of many different gases; N2 , CO2 , H2O and O2 . One of the most dangerous is CO, carbon monoxide. This gas has the potential to kill people and animals if concentrations are high enough. Hydrocarbons come from unburned fuel. NOx are released through the combustion process and have been linked to acid rain and ozone. One of the ways to reduce the emission from the exhaust gas is Exhaust Gas Re-Circulation (EGR), where certain amount of exhaust gas released out from the exhaust manifold is cooled and directed into the inlet manifold. Complete combustion of fuel leads to minimum emissions. A double pipe, counter flow heat exchanger was designed for this purpose. The present work deals with the effect of EGR on performance characteristics like specific fuel consumption, brake thermal efficiency and exhaust gas temperature. The high consumption of diesel fuel not only in agriculture section but also in transport sector compels for the substitution of diesel fuel with suitable alternate fuel. Hence, performance characteristics with diesel and cotton seed oil as fuel in a conventional, unmodified diesel engine with and without EGR are compared in the work. Experiments were conducted on vertical, 4 stroke, single cylinder (with electric generator) diesel engine with various EGR percentages and without EGR. It was observed that, at 15% EGR with diesel as fuel, engine performance improved and there is very minute effect of varying EGR percentage of cotton seed oil though the performance is relatively good.