基于缸盖振动的燃油喷射系统故障诊断

Fuel Injection System Fault Diagnosis Based on Cylinder Head Vibration Signal

对V型12缸柴油机缸盖振动燃烧段信号与缸内压力进行了时域对比,分析了失火时的缸盖振动响应,研究了供油规律随转速变化情况。分析表明缸盖振动中包含喷油器针阀落座的振动响应,研究了基于短时能量动态双阈值端点检测提取针阀落座响应时间特征的方法,利用振动信号的峰值加速度来表征针阀落座的强度。在不同工况及不同状态下提取了针阀落座时间及强度的振动特征,结果表明：振动特征能够有效反映针阀的工作情况,可以用于燃油喷射系统故障的诊断。

This work focuses on combustion stage signal of 12-cylinder diesel engine cylinder head vibration.There is the vibratory response signal of fuel injector needle valve crash which is proved by the time domain analysis between cylinder head vibration and in-cylinder combustion pressure,analysis for cylinder head vibration of misfire and analysis of fuel feeding law change with engine rotating speed.The dynamic dual threshold values end point detection method can get the start time of the fuel injector needle valve crash vibratory response signal which can describe the fuel injector needle valve closing timing.The acceleration peak of fuel injector needle valve crash vibratory response signal can describe crash strength.The characteristics extracted from vibratory response signal of injector needle valve crash under different work conditions and faulty conditions are analyzed.From the results it is revealed that these characteristics can accurately describe injection information and can be used for fuel injection system fault diagnosis.