【作者】

Panagiotis Kyrtatos

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。ABSTRACT Recent and future NOx emission legislation has placed increasing pressure on engine manufacturers to adopt additional NOx emission reduction measures. A well-established method for NOx reduction in Diesel engines is the use of cooled Exhaust Gas Recirculation (EGR), which reduces the flame temperature resulting in lower NOx formation. The adoption of EGR results in increased soot emissions due to the lower flame temperature and reduced oxygen availability, both of which hamper soot oxidation. Using water-in-fuel emulsions, past research has shown that the soot emissions can be reduced, a process which is understood to take place due to changes in spray and chemical kinetics. In this paper the combination of EGR and Fuel-Water Emulsions (FWE) is tested on a prototype two-stage turbocharged six-cylinder 1MW Wärtsilä W20 Common Rail medium speed diesel engine. The exhaust gases are recirculated to the intake using a semi-short EGR system, which directs part of the exhaust gases from the high pressure exhaust manifold, through an EGR cooler, to the intermediate pressure intake manifold before the high pressure (HP) compressor. The EGR is then compressed to the high pressure intake manifold along with the charge air using the HP compressor. The FWE is performed on-line using a prototype system which injects the water into the fuel directly before the high pressure fuel pump. This leads to no requirements of additional additives to keep the water emulsified in the fuel. The focus of this study is placed on the emission reduction potential of the combination of EGR and FWE, with focus on NOx and soot emissions. At high EGR levels and medium load, the results show a >60% reduction in exhausted particulate mass combined with a slight reduction in NOx emissions at constant fuel consumption, when using 15% water-in-fuel by mass. Compared to the non-EGR engine, NOx is reduced by >80%, while particulate mass is increased by about a factor of 3 when using 15% water, compared to a >9 times increase when using no water addition. Overall, this paper presents the advantages of combining EGR and FWE in terms of emissions. In addition, it shows the effectiveness and flexibility of the newly developed on-line FWE system, which allows instantaneous variation of water amount under all loads, while minimizing the requirements for moving parts.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

3

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