基于内部残余废气的汽油HCCI燃烧过程离子电流特性

Ion Current Characteristics of Gasoline HCCI Combustion Process Based on Internal EGR

燃烧相位和燃烧状态在HCCI燃烧控制中至关重要．为了控制该过程，需要一个来自某种燃烧传感器的反馈信号来确定实际燃烧过程的状态．通过对动态工况下火花塞离子电流与HCCI燃烧相位和燃烧状态的相关性进行研究，分析了离子电流的影响因素，提取出与燃烧相关的离子电流特征参数．结果表明，离子电流拐点相位、峰值相位与HCCI燃烧相位有很好的线性相关性，其相关系数在0．95以上，可以用于燃烧相位在线检测；离子电流峰值、积分面积和拐点值与燃烧负荷的相关系数都在0．65～0．73之间，可以在一定程度上反映燃烧负荷情况．通过检测离子电流信号用于HCCI燃烧指示并用于燃烧过程闭环控制．

Sensing of combustion phase and combustion state is very important for gasoline HCCI engine control. This paper studies the correlation of spark plug ion current and state of HCCI combustion in several dynamic operations in a gasoline HCCI engine based on internal EGR. Characteristics of the ion current detected by spark plug from HCCI combustion are defined as a set of parameters. Results show there is a good correlation between HCCI combus- tion phasing and maximal value phasing as well as curve inflexion phasing, and the correlation coefficient is more than 0.95, which can be used to detect the HCCI combustion phasing. The correlation coefficients between combustion load and maximal value, integration value and inflexion value of ion current curve are 0.65--0.73, which can be used to reflect HCCI combustion load rather than detect it.