汽车用氧传感器de研究与进展

汽车尾气中的有害物主要有CO、HC、NOx、SOx以及一些微粒物质,给人类赖以生存的大气环境带来了严重的危害.用氧传感器对汽车发动机的空燃比进行调节,控制发动机中的燃烧过程,可以达到减少污染和节约能源的双重目的.目前适用于汽车空燃比控制的传感器主要有三种:氧化物半导体型(TiO2传感器)、浓差电池型(ZrO2氧传感器)、极限电流型.本文在介绍了这三种汽车用氧传感器的原理、结构的基础上,重点介绍了一种新型极限电流型氧传感器一致密扩散障碍层极限电流型氧传感器,并简要分析了其发展趋势.     

基于氧化锆电解质的NOx传感器的检测系统设计

设计了一套用于测量汽车尾气排放的氮氧化物（NO与NO2）的车用传感器的检测装置。该装置能真实模拟汽车尾气的环境,测试了尾气温度、尾气流量、尾气中的O2浓度、NO浓度、NO2浓度等因素列代表NOx实际浓度的传感器极限电流IP2的影响,并对响应曲线进行了分析。该测试系统对所制作的NOx传感器内部结构及各电极的成分的改进具有重要的意义。     

薄膜型氧传感器特性及应用

本文介绍一种薄膜型氧传感器,该传感器主要用于汽车尾气排放监测,具有较好的特性与结构,对汽车工业向环保型方向发展有积极意义。     

氧气对NOx传感器气敏特性的影响

实验采用丝网印刷技术制作了以钇稳定氧化锆固体电解质(YSZ)为固体电解质、NiO为敏感电极和Pt为参考电极的混合电位型NOx传感器,并在高温(450～750 ℃)含NO和O2气氛中测试其气敏性能.测试结果显示该传感器在450～500 ℃和550～750 ℃时分别表现为电势幅值随温度升高而减小的正电势和负电势;同一NO浓度下,电势和半圆弧型阻抗谱只是随着O2含量在一定范围内的增大而分别增大和缩小.考虑到O2会把NO氧化成NO2,同时结合对传感器的理化性能、响应电势和阻抗谱及工作机理的的分析,研究了O2对NOx传感器气敏性能的影响.     

混合位型NOx传感器的研究与进展

混合位型NOx传感器是新近发展起来的一种NOx传感器。主要介绍了混合位型NOx传感器的研究情况及固体电解质材料（ZrO2）的工作机理。简要分析了传感器研究的发展方向。     

氧化锆基片式NO_x气体传感器的研制

采用具有自主知识产权的制备工艺流程,制备了氧化锆基NOx气体传感器。首先配制了性能良好的5mol%-ZrO2浆料,流延成型得到了氧化锆陶瓷素坯基片,经过剪裁、冲孔、开槽、丝网印刷等工艺,制备了传感器素坯,经过1450℃2h烧结得到了氧化锆基NOx传感器。应用线性伏安法初步测试了该NOx气体传感器的性能。制备的NOx气体传感器具有良好的NOx气体响应性能。初步性能测试结果表明,传感器的电流值和NO2气体浓度之间存在着强的线性相关性,线性相关系数99.27%,电流值在0.136A~0.142A之间,传感器的线性范围为:200ppm~2000ppm。     

电流型氮氧化物传感器输出特性分析及控制策略的优化

为提高基于钇稳定氧化锆固体电解质的电流型氮氧化物（NOx）传感器的测量精度,本文设计了基于LabVIEW模块化软件的NOx传感器全开放测试系统。本文对传感器工作原理进行分析并优化了氮氧化物传感器的控制策略。在研究过程中,作者首先对NOx传感器的各个功能模块进行独立测试,得到传感器的最佳工作温度及主泵、辅助泵、测量泵的极限电流输出特性曲线。分析的结果表明：传感器具有良好的饱和电流平台,并且随着传感器工作温度的升高极限电流不断增大;随后,作者在对传感器的气敏特性的进一步测试中发现：传感器在定电压控制策略和含氧环境下,传感器的极限电流与NOx浓度存在优良的线性关系;最后,作者提出了一种适用于含氧气环境的NOx传感器定电压控制策略。     

平板式二氧化锆氧传感器的研究进展

由于日益严格的排放法规,平板式二氧化锆氧传感器将成为汽车尾气控制应用的主流传感器。介绍了平板式氧传感器的制备工艺、结构和三种平板式氧传感器的工作原理并进行了对比。最后,展望了平板式氧传感器的发展前景。     

PPB级锆基安培型NO气体传感器性能的研究

采用丝网印刷技术制备了以In2O3为敏感电极的锆基安培型三电极NO传感器用以探测10-9级NO气体。用X射线衍射仪（XRD）和扫描电镜（SEM）对该传感器进行了理化分析;通过测量其在不同温度和不同NO浓度的气氛中的伏安特性曲线和时间响应曲线,研究了传感器的电流输出信号和NO浓度的关系以及时间响应特性。实验表明：在350℃~500℃测试温度范围内,极化电压为-60 mV,NO浓度变化为0~900×10-9时传感器响应电流的变化值Δcurrent和NO浓度之间存在较好的线性关系并且传感器在400℃时响应值最大。在被测气体总流量为100 cm3/min时,传感器信号90%的响应和恢复时间分别为18 s和12 s。传感器信号不受CO2浓度变化的影响,传感器的响应信号在测试时间里具有较好短期稳定性,但长期稳定性有待进一步提高。本文还采用阻抗谱分析方法对传感器的响应机理进行了初步的探索。     

汽车智能传感器自动测试系统的设计和建立

NOx传感器的开发是出于对环境的保护,它用于检测汽车尾气排放的氮氧化物浓度。在传感器的开发过程中,传感器输出信号的自动测试是一个重要的步骤。设计了一种基于LabVIEW的友好的用户测试软件,用于传感器数据的实时测试、评估和错误检测,该数据通过CAN总线传输。CAN总线是汽车领域中应用最广泛的通信协议之一。基于LabVIEW建立的自动测试系统具有配置功能、CAN总线数据帧的显示和解码、CAN总线错误的检查、解码信息的测试和评估、报表的生成、信号的设置和验证等功能。     

Titania NOx sensors for exhaust monitoring

Oxide semiconductors have been examined to develop NO_x sensors for exhaust monitoring. Titania doped with trivalent elements, such as Al³⁺, Sc³⁺, Ga³⁺ or In³⁺, has a good sensitivity and selectivity to NO between 450 and 550 °C, and shows rapid response. A sensor probe for monitoring exhaust NO_x has been fabricated. Many kinds of interference gases, such as C₃H₆, CO and SO₂, have been found to have only a slight influence on the sensor response to NO. The influence of O₂ and H₂O is also negligible, except for the cases of 0% H₂O and fuel-rich conditions. In accordance with these results, the sensor probe operates satisfactority in the exhaust gas of various combustion conditions without interference from the various kinds of gas species in the exhaust gases.     

Deep UV based DOAS system for the monitoring of nitric oxide using ratiometric separation techniques

The investigation of an ultra violet DOAS (differential optical absorption spectroscopy) sensor based on fibre-optic technology for the monitoring of nitric oxide gas in an exhaust environment is described. Cross-sensitivity issues with other gases present in the environment were realised and ratiometric separation techniques were developed in order to reduce the sensor's susceptibility to these interferences. Experimental results describing the calibration of the sensor against a commercial analyser and tests documenting the sensor's operating capabilities within the exhaust of an engine are presented. The lower limit of detection for the sensor was found to be 5 ppm with response times of 3.4 s.     

气敏元件的环境温度特性

研究了γ—Ｆｅ２Ｏ３、ＺｎＯ、ＷＯ３、Ｌａ１－ｘＳｒｘＦｅＯ３气敏元件的环境温度特性。环境温度改变时（－４０～４０℃）元件的阻值Ｒ０的变化依基体材料及检测气体而异，Ｌａ１－ｘＳｒｘＦｅＯ３乙醇元件最为稳定，ＺｎＯ和ＷＯ３的Ｈ２Ｓ元件的Ｒ０有明显漂移，但在一定浓度Ｈ２Ｓ中的Ｒｇ比较稳定。这几种元件均适于在ＶＨ＝５Ｖ下工作。     

用铈锆固溶体制备新型氧浓差型氧传感器

利用氧化铈—氧化锆固溶体储氧材料的储氧特性,使其作为固态氧分压参考层,制备了一种新型的用于监测汽车尾气排放的氧浓差型氧传感器,克服了传统浓差型氧传感器制作工艺复杂、成本高、不便于微型化的缺点。该传感器结构由钇稳定的氧化锆电解质、氧化铈—氧化锆固溶体氧分压固态参考层和铂电极组成。利用N2和O2的混合气体来模拟尾气对其分别在工作温度350,400,450℃进行测试,发现在空燃比为1附近电势发生突变,突变电势范围为520~-100mV。     

Comparative study on directional sensitivity of patch‐antenna‐based strain sensors

In this article, we present a comparative study into the directional sensitivity of patch‐antenna‐based strain sensors. Two linearly‐polarized (LP) patch sensors vs a circularly‐polarized (CP) patch sensor with identical configurations are demonstrated. The strain occurred in real structures is commonly uncertain, the usefulness of LP‐patch sensor becomes limited. Like the conventional strain gauges, it can only be used if the strain direction is known beforehand. Therefore, a nearly‐square CP‐patch sensor for multi‐directional strain monitoring is proposed here. In order to obtain high sensitivity, three novel strain sensing methods are proposed for strain monitoring. Multi‐directional strain sensing is achieved by a proof‐of‐concept prototype. The simulated results verified by experimental results show that high sensitivities of these three methods were achieved.     

CuO—ZnO异质结气体传感器的敏感性能

ＣｕＯ—ＺｎＯ异质结气体传感器是一种新型的气体传感器,它有成本低、工艺简单、检测方便等诸多优点。主要研究了ＣｕＯ和ＺｎＯ不同比例情况下,该传感器的气敏性能。测试了它的阻温特性,及在不同温度、不同气氛条件下的灵敏度和响应特性,并从理论上对测试结果进行了分析和讨论。     

Optimal refractive index design for an optical fibre-based evanescent field sensor

Optical fibre-based evanescent field sensors are proving to be viable and useful in the detection of chemicals, toxins, gases and other species. Such fibre sensors rely on weak interactions between the surrounding environment and the external “evanescent” field associated with bound modes of electromagnetic radiation propagating through an optical fibre. Of fundamental importance in the design of such sensors is the fraction of the total guided field power that propagates as the evanescent field. By increasing this relative evanescent field power, sensor gain can be improved. As the evanescent field is determined by the refractive index profile (RIP) of the sensor and the surrounding environment, design of the sensor RIP is critical. This paper presents a rigorous approach to this RIP design problem, formulated in terms of an optimization problem with the normalized evanescent field power as the payoff, RIP as the input, and a simple electric field model as the constraint. An RIP design procedure utilizing dynamic programming is then presented, along with an example that illustrates the improvement obtainable over existing designs.     

固态混合电势气体传感器的原理和应用

由于日益严格的排放法规,固态混合电势传感器将成为汽车尾气控制和环境气体检测必不可少的传感器.本文介绍了此类传感器结构和混合电势传感器的工作原理和应用.     

基于电化学的固态CO2传感器研究进展

用于检测环境中气体的电位传感器已经在传感器技术领域发展为一个成熟的方向。由于在各个行业有着广泛的应用,可靠廉价的CO2传感器有着巨大的市场潜力。总结了基于电化学的固态CO2传感器类型,分析了它们的检测过程,提供关于其传感原理和特性研发的广泛概述,并描绘了基于电化学的固态CO2传感器在未来各种应用的可能性。     

A mid-infrared optical fibre sensor for the detection of carbon monoxide exhaust emissions

An optical fibre presented is capable of monitoring the presence of carbon dioxide and carbon monoxide in the exhaust system of petrol engines. At present there exists no commercial sensor, which is capable of providing online measurements of these exhaust gases as required by European legislation. The design of this sensor using low cost and compact mid-infrared components, which make it suitable for insertion into a vehicle, is presented. Results are presented for 200 ppm step changes in concentration of carbon monoxide supplied from a laboratory controlled supply is presented.