【作者】

Gerhard Pirker

【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。To obtain NOx emissions that fall below the increasingly lower NOx limits with prechamber gas engines, it is not enough to merely increase the excess air ratio in the main combustion chamber; this would result in significant losses in engine efficiency. Instead, it is necessary to focus on the NOx emissions created in the prechamber in particular since these greatly contribute to the total amount of NOx emissions. Thus when developing combustion concepts for prechamber gas engines, attention must be paid to finding ways to reduce NOx in the prechamber without compromising the effectiveness of flame torches in initiating combustion in the main combustion chamber. This article will make use of engine measurements to show what challenges arise as a result of high prechamber NOx emissions. The main emphasis is placed on a methodology that is capable of characterizing the origin of NOx emissions. Next, the causes of NOx formation in the scavenged prechamber are investigated by conducting detailed analyses of test bed measurements. Advanced analytical tools that rely mainly on 0D models and analysis methods are applied to perform calculations of the thermodynamic conditions in the prechamber in order to calculate prechamber NOx. These tools are also capable of calculating the charge composition in the prechamber at ignition timing which is relevant information for ignition and flame propagation. The flow of nitric oxides between prechamber and main combustion chamber is considered as well. Thorough knowledge of parameters related to the prechamber such as prechamber pressure curve and prechamber gas amount, composition of the scavenging gas and timing of the admission is imperative. The described methodology is used for developing combustion concepts for highest efficiencies that are able to accomplish also future low NOx emissions levels prescribed by law. In addition, it is shown what impact various prechamber parameters (amount of prechamber gas, prechamber geometry, etc.) and different types of scavenging gases such as hydrogen and reformer gas have on prechamber NOx formation. The interaction between the prechamber and the main combustion chamber will be analyzed in detail.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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