论文部分内容阅读
3.3 氧传感器波形配合喷油脉宽检查分析图5所示为发动机在2 500 r/min时的氧传感器波形和喷油波形。氧传感器波形为不正常的持续浓混合气信号(上边波形),而ECU能正确地发出较短的喷油脉宽指令(下边波形,正常应为5 ms)试图使混合气变稀。两个波形的关系是正确的负反馈关系,这说明故障不在空燃比反馈控制系统,可能是燃油压力过高或喷油器存在泄漏等。若氧传感器波形为不正常的持续稀混合气信号(低电压),而ECU能发出较长的喷油脉
3.3 Oxygen sensor waveform with injection pulse width check analysis Figure 5 shows the oxygen sensor waveform and injection waveform of the engine at 2 500 r / min. The oxygen sensor waveform is an abnormally continuous rich gas signal (upper waveform), and the ECU can correctly issue a shorter injection pulse width command (lower waveform, normally 5 ms) in an attempt to dilute the mixture. The relationship between the two waveforms is the correct negative feedback relationship, indicating that the fault is not in the air-fuel ratio feedback control system, which may be excessive fuel pressure or injector leakage. If the oxygen sensor waveform is abnormal, the continuous lean mixture signal (low voltage), and the ECU can emit a longer fuel injection pulse