基于UEGO信号电平检测汽油机异常燃烧的研究

Study on the abnormal combustion of gasoline engines by the signal of universal exhaust gas oxygen sensor

【目的】为了研究汽油机异常燃烧状况,利用IBIM综合测试盒实时测定BMW N20四缸汽油机宽域氧传感器(UEGO)的信号电平突变值,以此识别和判断异常燃烧的原因.【方法】试验分析了稳态燃烧、急加减速、喷油脉宽异常、间歇性失火、进气真空泄露及自身故障引起的氧传感器信号电平波形变化.【结果】喷油脉宽异常(窄)时波形为电平持续偏低浓混合气异常信号;间隙性失火时波形出现系列电压尖峰杂波;真空泄露时波形为电平持续偏高稀混合气异常信号;氧传感器损坏时波形为恒定电压值异常信号.【结论】气缸内混合气燃烧不正常将导致氧传感器信号波形异常;不同原因引起的氧传感器信号杂波,其形态会有区别;利用波形分析方法可以区分不同杂波所对应的异常燃烧原因.

【Objective】To research the state of abnormal combustion,experiments were conducted on an N20 BMW four cylinder gasoline engines to measure the signal mutation value of universal exhaust gas oxygen sensor（UEGO）and identify the reason for in-cylinder abnormal combustion.【Method】Experiments analyzed signal waveform of UEGO under the conditions of normal combustion,rapid acceleration and deceleration,abnormal fuel injection pulse width,intermittent misfire,intake-air leakage and its own faults.【Result】The waveform was an abnormal signal with continuous low voltage value when the fuel injection pulse width was narrowed.The waveform showed a series of abnormal voltage spikes when the engine was interstitial misfire.The waveform was an abnormal signal with high voltage value when a vacuum leak occurred in the intake duct.The waveform was an abnormal constant voltage value when the UEGO was damaged.【Conclusion】In-cylinder abnormal combustion would cause abnormal signal waveform of oxygen sensor,the types of signal clutters caused by different reasons were different,and waveform analysis method could be used to distinguish the reasons for the abnormal combustion corresponding to clutters.