Impact of Cold and Hot Exhaust Gas Recirculation on Diesel Engine
Today most of the transport vehicles in countries like India where cost effective is the predominant criteria utilize diesel engines rather than petrol engines. From past 5 years usage of diesel engines was rapid which can be addressed from the sales report of many automobile companies. The reason behind this could be cost of diesel fuel and efficiency of the diesel engine when compared to petrol engine. But when we look on the worse side of diesel engine, emissions from diesel engine are high especially NOx. So there is a need for a technique which could reduce the emissions without affecting the performance of engine. One such technique could be Exhaust gas recirculation. Present paper aims to find the impact of cold and hot EGR on emissions of diesel engine.
Performance and Emission Analysis of Diesel Engine with Exhaust Gas Recirculation: A Review
: The cost of diesel is lesser than gasoline and also diesel have higher efficiency that’s why now-a-days, the use of diesel engines are higher than petrol engines. The performance of diesel engine is mainly depends on compression ratio, air-fuel ratio, speed etc. With increasing compression ratio the efficiency of diesel engines increases. But the exhaust gas from diesel pollutes the environment. There is big problem associated with diesel engine that is NOx formation. NOx contribute to a wide range of environment effects including the formation of acid rain and destroy ozone layer. The main causes for NOx formation are high in-cylinder temperature and high oxygen concentration. So there is a need for a technique which could reduce the emission without affecting the performance of engine. One of such technique is EGR (exhaust gas recirculation). EGR is a common way to control in-cylinder NOx formation. A review have been made to analyze the performance and emissions characteristics of diesel engine with EGR.
The Study of Relationship between Berm Width and Debris Flow at the Slope
The purpose of this study is to estimate the behavior and the mechanism of debris flow at the end of mountain side when a berm was set on the inclined plane. The numerical model was performed by using the Finite Difference Method(FDM) based on the equation for the mass conservation and momentum conservation. In order to measure the behavior of the debris flow, the debris flow of a straight channel slope and the debris flow of channel slope with 3 types of berms were compared. First, the flow discharge and the sediment volume concentration at the downstream of the channel slope, depending on the various berm width and the different inflow discharges at the upstream of the channel were analyzed. The longer the berm width, the flow discharge at the downstream of the channel was decreased and the high flow fluctuation was reduced by a berm. And it means that a berm can effect for the delay of the debris flow. Through Root Mean Square ratio(RMS) comparison, the flow discharge of the channel slope with a berm was lower than that of a straight channel slope. The longer the berm width, for the sediment volume concentration, an inflection point did not show but mild curve. Because the low sediment concentration with water mixture by a berm continuously flow at the downstream end, it will be effect for reducing the disaster caused by debris flow. The results of this study will provide useful information in predicting and preventing disaster caused by the debris flow.