时域缸压信号爆震识别及强度评价的动态窗口域方法

针对时基缸压信号的爆震检测,引入爆震能量相对标识参数ΔE_I表征高通爆震信号在爆震窗口和参考窗口内的累积积分能量之差.随机选取若干爆震事件和非爆震事件,计算各事件的ΔE_I和爆震因子K_F随窗口宽度的变化.计算结果表明:爆震事件的ΔE_I随窗口宽度的增加而逐渐增大,但当窗口宽度增加到一定程度时,ΔE_I会达到最大并基本保持恒定;据此现象进行爆震窗口域的动态判定,可准确识别爆震发生和合理评价不同工况下的爆震强度.分别采用西门子VDO角基算法和时基动态窗口域方法对表征各种爆震倾向的154FMI、156FMI和171FMI小型高速汽油机进行了爆震检测.测试结果表明:基于两种方法的爆震识别和强度评价具有良好的一致性.

Dynamical Identification of Signal Window Width for Knock Detection Based on Time-Domain Cylinder Pressure Signals

Knock detection based on cylinder pressure signals in time-domain was investigated. The identification parameter ΔE_I was introduced to characterize the accumulative energy difference between high-pass cylinder pressure signal in a knock window and in a reference window. The identification parameter ΔE_I and the knock factor K_F of knock and non-knock cases were calculated for different signal window width. It was found that the identification parameter ΔE_I would increase to maximum and then remain constant as the signal window width increased to a certain value, which can be used to identify the knock occurrence and knock strength under various engine operating conditions. Knock detection of Model 154FMI, 156FMI and 171FMI small high speed gasoline engine was carried out by using the angle-domain method of Siemens VDO and the time-domain method of dynamical signal window width, and the detected results of both methods agreed well.