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.
Effect of Exhaust Gas Recirculation on Performance and Emission Characteristics of a Diesel Engine
The exhaust system of a single cylinder, four stroke Direct Injection Compression Ignition (DICI) engine was modified to allow for exhaust gas recirculation (EGR) in order to investigate its effect on performance and emission characteristics of the engine. The EGR system was developed and tested with EGR rates of 0%, 10%, 20% and 30%. The effect on performance parameters of brake specific fuel consumption, brake power and brake thermal efficiency was studied. Emissions of carbon monoxide, unburned hydrocarbon and carbon dioxide were also recorded. The performance and emission characteristics of the engine under EGR were compared with those of the engine operation without EGR. The results showed that EGR leads to a decrease in specific fuel consumption and increase in brake thermal efficiency. With increase in percent (%) of EGR, the BSFC decreased by up to 10.71% at quarter load and decreased by up to 6.76% at full load. The percentage increase in brake thermal efficiency was up to 12.01% at quarter load and up to 14.52% at full load. On the other hand, the brake power decreased by up to 6.13%. Exhaust emissions of HC and CO, both increased with EGR by up to 26.57% and 30.48% respectively. Emission of CO 2 however, decreased with EGR.
Chip scale packaging using chip-on-flex technology
An increasing number of electronic designers, fabricators and users see Chip Scale Packaging (CSP) as a way to obtain the benefits foreseen in multichip packaging and Chip-on-Board (COB) without the problems and limitations currently associated with each. The Chip-on-Flex (COF) multichip packaging technology has been demonstrated to be applicable to single chip packages that meet chip scale packaging goals. This paper looks at the Chip-on-Flex Chip Scale technology and addresses issues including the process, structure, assembly, yields and reliability.