HCCI燃烧离子电流特性试验研究

An Experimental Study on the Ion Current Characteristics in HCCI Combustion

在一台单缸试验机上通过改变进气温度、燃空当量比和压缩比等燃烧边界条件,对离子电流信号的波形变化进行了研究。结果表明,离子电流信号受到上述条件的强烈影响,其根本原因在于缸内峰值温度对自由离子浓度变化的作用。温度升高,燃烧较好时,自由离子浓度增加,离子电流信号增强,相位提前;温度降低,燃烧变弱时,自由离子生成受到抑制,信号减弱,且相对燃烧的相位滞后趋于增加。

A study on the wave pattern variation of ion current signal is conducted on a single cylinder test engine by changing combustion boundary conditions such as inlet temperature, fuel-air equivalence ratio and compression ratio etc. The results indicate that ion current signal can be strongly influenced by combustion boundary conditions, and its root cause is the effects of in-cylinder temperature peak on the concentration of free ion. When temperature rises, resulting in better combustion, the concentration of free ion increases and the ion current signal becomes stronger; while the fall in temperature weakens the combustion and suppresses the generation of free ion, leading to weak signal and its phase lag relative to combustion tends to increase.