利用氧传感器诊断电控发动机故障

基金项目:

山东省交通厅资助项目 J9913

Diagnosing electron-controlled gasoline engine default by exhaust gas sensor

摘要: 介绍了氧传感器基本工作原理和检测方法，提出了用氧传感器波形诊断带有三元催化反应器的发动机故障的方法，并给出了具体诊断实例。
- 氧传感器 /
- 诊断 /
- 电控发动机
Abstract: The default of ignition system, fuel supply system, electricity system and mechanical mechanism of gasoline engine with carburetor may be diagnosed by secondary ignition wave displayed on automotive oscilloscope, but the running condition ofelectron-controlled engine with three way catalytic converter must be understood only by means of waveform of exhaust gas sensor instead of secondary ignition.If A/F deviates from its theoretical value(14.7), three way catalytic converter's capability to reduce CO, HC and NO_x emissions will rapidly drop.The exhaust gas sensor installed on exhaust gas pipe measures A/F according to oxygen concentration in exhaust gas, and sends feedback signal to ECU in order that A/F converges on its theoretical value.This paper discuses how to analyze electron-controlled engine trouble and its causes using waveform of exhaust gas sensor.
- exhaust gas sensor /
- diagnosis /
- electron-controlled gasoline engine

图 1 氧化锆型氧传感器的结构

Figure 1. The structure of Z_rO₂ oxygen sensor(O₂S)

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图 2 氧传感器在排气管中的布置

1-陶瓷体；2-铂电极；3、4-电极引线点；5-排气管；6-陶瓷防护层；7-排气；8-大气

Figure 2. The arrange of O₂S in engine exhaust pipe

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图 3 氧传感器电压特性

Figure 3. The voltage characteristic of O₂S

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图 4 氧传感器输出信号

Figure 4. The output signal of O₂S

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图 5 氧化钛型氧传感器的结构

Figure 5. The structure of TiO₂ oxygen sensor(O₂S)

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图 6 用丙烷法检测氧传感器

Figure 6. Testing O₂S by propane method

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图 7 利用氧传感器分析发动机故障流程图

Figure 7. The flow chart of analyzing engine fault by means of O₂S

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图 8 上海帕萨特（PASSAT）B5轿车发动机喷油器损坏时氧传感器波形

Figure 8. The O₂S waveform when oil spraying nozzle of Shanghai PASSAT B5 engine is damaged

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表 1 氧传感器规格

Table 1. O₂S specification

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