【作者】

Matteo Imperato

【摘要】

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。The new limits for NOx emission in ECA countries for large-bore engines in effect since 2016 bring the law values close to zero. Since NOx are mainly formed in high temperature zones, the research has been oriented towards reducing the combustion temperature by low compression temperature or using gas fuels. However, exhaust gas recirculation has been adopted with success for a few decades in high-speed diesel engines. This study describes the application of exhaust gas recirculation in a single-cylinder large-bore medium-speed research engines: the system permits to cool the exhaust gas and mix them with the charge air in the intake manifold, likewise in smaller engines. Tests were carried out with exhaust gas rate up to 30% at engine load ranging from 10 to 20 bar, as indicated mean effective pressure. All the tests were run at constant speed of 900 rpm. In addition, two injection pressure levels were tested. The results showed that exhaust gas in the mixture charge reduced the combustion temperature, abating NOx up to 95%. However, this implied longer combustion duration worsening the engine fuel economy. To improve the fuel economy, Miller cycle was applied and exhaust gas rate reduced. The outcomes claimed more favorable NOx-fuel consumption trade-off to meet the law limits, which can be optimized by tuning the injection pressure and timing.

【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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