【作者】

Takahiro Kuge

【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 In this day and age, emission regulations such as GHG and NOx become gradually strict for marine engines. Premixed gas engine is in spotlight because of the advantage of its reduction on GHG and NOx emissions. In particular, lean premixed combustion technology has great potential to reduce NOx emission without an exhaust gas after treatment system, and it has been mostly developed in 4-stroke medium speed gas engines. On the other hand, to satisfy lean pre-mixture in 2-stroke low speed gas engines, there are the following technical difficulties to overcome because of its gas injection during scavenging period. (1) Gaseous fuel slipping through exhaust valve (2) Unexpected ignition due to contact with hot residual gas and gas mixture (3) Quick gas mixing is needed to inhibit abnormal combustion (pre-ignition, rapid combustion and end gas autoignition). Therefore, the technology concerning mixture formation is a key point for developing 2-stroke premixed gas fueled engines. This paper describes the mixture formation process and feasibility in 2-stroke lean premixed combustion gas engine by using CFD analysis and elementary test. Gaseous fuel is injected from the injectors mounted on the cylinder liner between the scavenging port and exhaust valve. The mixture formation process is investigated by CFD simulation and visualization experiment using 200 mm diameter acrylic cylinder. The CFD result shows that gaseous fuel jets in crossed swirl flow reach the cylinder center and mix with fresh air. The jet trajectory of CFD has good agreement with the visualization result. Optimization of injection timing can almost control non-contact with hot residual gas, and also minimize gaseous fuel slipping through exhaust valve. Furthermore, the effect of injection system on mixing process is studied by CFD simulation. The result shows that the scavenging port injection system, which gas nozzles are mounted on each scavenging port, improves mixing and in addition, optimizing swirl flow provides further mixing.

【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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