宽域废气氧传感器控制方法研究及实现

发布时间：2018-05-21 09:33

本文选题：宽域废气氧传感器 + 空燃比　；参考：《合肥工业大学》2017年硕士论文

【摘要】：宽域废气氧(Universal Exhaust Gas Oxygen,简称UEGO)传感器具有较宽的空燃比测量范围,广泛地应用于稀燃发动机空燃比控制系统,能够为汽车电子控制单元(Electronic Control Unit,简称ECU)提供更加准确的空燃比信号,保持发动机气缸内混合气在理论空燃比附近,减少汽车尾气对空气产生的污染。UEGO传感器需配以相应的控制器才能正常工作,控制器的优劣直接决定传感器的性能。本文主要研究UEGO传感器的控制方法和控制系统软件。通过空气环境中的开环实验,建立温度模块的数学模型,针对温度的非线性和冷启动加热限制,提出斜坡加热与模糊PI相结合的分段控制策略。在混合气配气平台上进行泵电流模块的开环实验,建立不同工况下被控对象的数学模型,针对模型参数存在摄动,提出采用模糊PID控制方法。研制了UEGO控制器的系统软件,由初始化、看门狗、人机接口、上位机通讯、温度控制、泵电流控制、空燃比计算等模块组成,实现温度和泵电流模块的信号采集及控制、测量计算、人机交互等功能。使用LabVIEW开发上位机监控软件,实现控制参数设置、状态监控、结果记录和显示等功能。在空气环境中的实验结果表明:常温下传感器冷启动时间少于20s,温度控制精度较高;泵电流控制的调节时间为191ms,具有调节时间短,抗干扰能力强等优点。在混合气配气平台上进行动态实验,结果表明:所研制的UEGO控制器能够快速响应外界工况的变化,具有良好的动态性能。
[Abstract]:The wide range Universal Exhaust Gas Oxygen (UEGO) sensor has a wide air fuel ratio measurement range, which is widely used in the air fuel ratio control system of the lean burn engine. It can provide more accurate air fuel ratio signal for the electronic control unit of the automobile (Electronic Control Unit, abbreviated ECU), and keep the mixture gas in the engine cylinder. In the vicinity of the theoretical air fuel ratio (air fuel ratio), the.UEGO sensor that reduces the pollution of the automobile exhaust to the air needs to be matched with the corresponding controller to work normally. The controller's advantages and disadvantages directly determine the performance of the sensor. In this paper, the control method and the control system software of the UEGO sensor are mainly studied. The mathematical model, aiming at the nonlinearity of temperature and the limitation of cold start heating, proposes a piecewise control strategy combining slope heating with fuzzy PI. The open loop experiment of the pump current module is carried out on the mixture gas distribution platform, and the mathematical model of the controlled object under different working conditions is set up. The fuzzy PID control method is proposed in view of the perturbation of the model parameters. The system software of UEGO controller is developed, which consists of initialization, watchdog, man-machine interface, upper computer communication, temperature control, pump current control, air fuel ratio calculation and so on. It realizes the signal acquisition and control of the temperature and pump current module, measurement calculation and human-computer interaction. The control software is developed by using LabVIEW to realize the control parameter. The experimental results in the air environment show that the cold start time of the sensor at normal temperature is less than 20s, the temperature control precision is higher, the control time of the pump current is 191ms, the adjusting time is short, and the anti-interference ability is strong. The dynamic experiment on the mixture gas distribution platform is carried out. The results show that the developed UEGO controller can respond to changes in external conditions quickly and has good dynamic performance.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TP273

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