汽油车前氧传感器响应性能主动诊断策略研究

本文提出一种基于频率和振幅的汽油车前氧传感器电压信号响应性能主动诊断策略。通过在特定工况下主动快速调整闭环燃油调节因子的波动幅度,以快速改变排气系统废气成分,并在合理的采样区间内计算氧传感器电压跳变频率与跳变振幅,测试氧传感器电压信号响应性能。以氧电压跳变频率对主动燃油调节过程进行监控,以氧电压跳变振幅作为故障诊断指标。实车试验验证的结果表明,所提出的诊断方法能有效诊断氧传感器从浓到稀迟滞、从稀到浓迟滞和双向迟滞等典型响应故障,具有良好的实用性。     

宽带型氧传感器故障探析

氧传感器用于检测排气中氧的含量,发动机电脑依据排气中氧的含量判断混合气的浓度,及时地修正喷油量。传统的氧传感器在混合气浓时,输出一个约0．6～0．9V的电压,当混合气稀时,输出一个约0．1～0．3V的电压,ECU依据氧传感器输出电压值判断混合气浓或稀,因为在反复的修正喷油量,所以氧传感器的电压在0．1～0．9V之间波动。     

英国凯旋摩托车E-OBD技术简介（2）

（上接2010年第1期） e）模式5：请求氧传感器检测测试结果 氧传感器是凯旋E-OBD摩托车上非常重要的排放控制部件，ECU根据氧传感器的测量信号判断混合气的稀、浓，适时调整喷油量，使混合比入始终收敛于理论空燃比14．7附近，以保持三元催化转化器的最高转化效率。因此，氧传感器的性能指标是非常重要的。由于氧传感器处于高温状态下工作，易于受油气污染而损坏。因此系统必须时刻检测氧传感器的特性参数，以确保E-OBD可靠监测，全程控制摩托车排放达标。     

宽带型氧传感器

氧化锆型氧传感器的工作范围是在λ=1附近产生一个跳跃性的输出电压变化,一旦超出此范围,其反应性能便降低。当发动机需要作稀混合或浓混合控制时,这一类型的氧传感器便无法胜任了,使得发动机的燃油控制不能十分精确,所以才有宽带氧传感器的产生。新型的宽带氧传感器被用在宝来车的三元催化器     

闭环电喷系统中的氧传感器波形分析(2)

<正>(上接2014年第8期)正常情况下氧传感器的电压波形能够直观的反映各种工况下空燃比的实际变化量,图7为加/减速状态下的氧传感器波形。在减速断油状态,氧传感器输出低电压;而在加速状态,氧传感器输出高电压。加速开始与加速进行一段时间时的氧传感器电压值也不相同,这是因为加速开始时ECM执行的是加速加浓控制,短时间内延长喷油脉宽满足加速时的空燃比需要。随着加速后转速的上升,再逐渐缩短喷油     

浅析Lexus车系λ传感器工作原理及空燃比控制策略(三)

六、Lexus车系平面型空燃比传感器闭环反馈PID控制及自适应学习修正控制鉴于杯型阶跃式氧传感器的物理特性,信号输出电压在0.45V处会发生阶跃,近似于开关,因此其只可作为区分空燃混合汽是浓还是稀的两种状态,却不能确切地反映空燃混合汽浓/稀的具体程度,例如,当空燃混合汽稍浓时,信号反馈电压突变为0.6~0.9V;当空燃混合汽稍稀时,信号反馈电压突变为0.1~0.3V;倘若空燃混合汽进一步变浓或变稀,其信号反馈的输出电压依然处在上述两个区间范围,故对于过浓或过稀的空燃混合汽,借助杯型阶跃式氧传感器仅可作定性分析,不可作定量测量。这样一来,基于此类型氧传感器的空燃比闭环反馈修正及空燃比自适应学习修正在针对与目标空燃比的偏差控制上,速度、精度势必有所降低。     

日产风度A33发动机电控系统故障检测(二)

6.氧传感器的检测 该车发动机电控系统有前、后加热式氧传感器,均为陶瓷氧化锆制成,氧化锆在混合气浓时可以产生大约1V电压,在混合气稀时电压变为0。前加热式氧传感器位于前排气歧管上,用于检测排气中与外界空气相比氧气的含量;后加热式氧传感器位于三元催化装置后面,监测两侧排气管中的氧气含量。 (1).前加热式氧传感器的检测 故障现象: 来自传感器的电压持续为0.3V。 故障原因: ①.线束或连接器故障,传感器电路     

空燃比氧传感器(二)

图4表示的是全范围平板型空燃比传感器在实际空燃比数值小、浓混合气工况下的工作原理。实际空燃比数值小、浓混合气工况时,由于缺氧造成可燃混合气不能完全燃烧,从而产生了大量的未燃烧气体(碳氢化合物和一氧化碳)。实际空燃比数值越小、可燃混合气越浓,产生的碳氢化合物和一氧化碳越多。在此实际空燃比数值小、混合气浓的工况下,发动机电脑在两个空燃比传感器铂电极间施加电压,空燃比传感器空气腔内的氧气在空气腔侧铂电极得到电子后被电离变成氧离子,氧离子从空气腔侧铂电极流到尾气侧铂电极。在尾气侧铂电极,它同穿过空燃比传感器扩散阻…     

夏利汽车传感器的故障分析与检测

在电子汽油喷射式发动机上进行反馈控制的传感器是氧传感器。它安装在发动机的排气管上位于三元催化转化器前。它的作用是通过检测排放气体中氧的含量来获得混合气的空燃比稀浓信号．并将检测结果转变成电压信号输入ECU，ECU根据氧传感器输入的信号．不断地对喷油脉宽进行修正，使混合气浓度保持在理想范围内．实现空燃比的反馈控制，即闭环控制。     

95款别克传感器参数

r~-一~一~~----一~~-一~----一~-进气温度传感器电阻值温度(℃)电阻(O)loo17790241名0332704676066750973451 1884014593518023022382冬279620352015445Ql056705728009420一512300一1016180一152 1450一2028680一3052700一4010070()氧传感器电压值状态V稀0 .1浓l,0节气门位笠传     

基于变压差稳流气道试验台数据采集与处理系统的设计

基于变压差试验方法，在稳流气道试验台上，测量涡流动量矩、气门升程、气道压差、温度及流量等参数，上述各参数可用相应的传感器及放大器转变为电信号，再经A／D转换由计算机进行处理和分析，从而得出流量系数、涡流比等参数，改变了以往的手工记录和传统测试方法。     

SiC泡沫陶瓷用作柴油机尾气净化催化剂载体的研究

将具有三维连通网状结构的碳化硅(SiC)泡沫陶瓷作为柴油机尾气净化中HC和CO的催化剂载体,研究了SiC泡沫陶瓷的性能和电加热效果。结果表明:S iC泡沫陶瓷具有合适的电导率和良好的抗热震性能,适于用作电加热催化剂载体;可提高柴油机低温排气时HC和CO的转化效率。     

Numerical Analysis of the Mixture Formation in a Two-Stroke Wall-Guided LPG DI Engine for Extended-Range Electric Vehicle

The use of automotive LPG characteristics which are easy to evaporate vaporization and carry. The paper presents a design of extended-range electric vehicle for wall-guided two stroke LPG engine with direct injection combustion system. Based on the modified vehicle LPG spray model, a database describing the characteristics of vehicle LPG fuel was built and imported into the CFD software. And the accuracy of the model is verified by the Schlieren experimental results. The concentration and velocity field of the mixture in the cylinder under different load conditions are numerically analyzed. The analyzed result indicated that the start injection time θ = 60°–70°CA BTDC under part load condition, the plug electrode near the gathering of a richer mixture is easy to be fired at spark ignition time, the obvious formation of mixture in cylinder is formed and the overall air-fuel ratio is above 40: 1. The start-transition working condition and large load conditions in the piston moves upward before closing the exhaust port to start injection LPG. The optimized LPG injection start time θ ensures that the fresh gas is locked in the cylinder when the exhaust port is closed (63°CA ABDC). In the ignition time of the spark plug, an ideal homogeneous mixture in the cylinder is realized.     

电动汽车 CO2热泵空调制热性能分析

为提升电动汽车CO2热泵空调的系统性能及扩宽热泵空调的使用温区，构建了回热器+补气增焓的跨临界CO2系统，通过建立数值模型对该系统的制热性能进行了仿真分析。研究结果表明，气体冷却器压力对制冷系数 （Coefficient of Performance，COP） 影响较大，且存在最优气体冷却器压力和中间补气压力使COP达到最大值；中间补气过程能有效提升COP和制热量，且能有效降低压缩机排气温度；回热器过热度对COP和制热量影响较小，但会导致压缩机排气温度上升。     

索纳塔轿车电喷系统的检修

介绍了索纳塔轿车故障码的读取和清除方法，以及怠速、尾气排放的调整，洋细沦述了空气流量传感器、冷却液温度传感器、进气温度传感器、节气门位置传感器氧传感器、上止点／曲轴位置(TDC／CKP)传感器、喷油器、控制继电器和功率三极管的检测。     

车用柴油机EGR瞬态响应特性

应用自行开发的柴油机瞬态测试系统和电控EGR系统进行了EGR瞬态响应特性研究。结果表明:瞬态工况下由于EGR压差的增加和进气量的减小造成EGR率大幅度超调,增加幅值随瞬变率增加而增加;EGR本身会造成柴油机排气烟度增加,瞬态工况下EGR率的超调更加剧了这种恶化;与稳态工况相比,1600 r/min、5 s增负荷工况EGR率最大超调幅度达到43%,排气烟度增加6倍;2000 r/min增负荷工况EGR瞬态响应特性具有大致相同的规律。在发动机瞬变过程中需要制定相应的EGR瞬态控制策略,以降低瞬态排气烟度。     

Thermal load in D.I. diesel engine under EGR operation— measurements of steady state temperature of combustion chamber wall surface and intake gas temperature

The combustion temperature drops with exhaust gas recirculation (EGR), but the mean gas temperature in the combustion chamber may rise due to the rise of intake gas temperature and the drop of excess air ratio. For the verification of these effects, narrow J-type thermocouples were embedded in the piston and cylinder liner of an automobile D.I. diesel engine, and accurate measurements were conducted accordingly.In addition, the authors developed a measuring method of the intake gas temperature flowing between the intake valve and the seat to study the effect on the thermal loads on the combustion chamber wall.     

Measurement of hydrocarbon and carbon monoxide emissions during the starting of automotive DI Diesel engines

Most of hydrocarbon (HC) and carbon monoxide (CO) emissions from automotive DI Diesel engines are produced during the engine warm-up period and are primarily caused by difficulties in obtaining stable and efficient combustion under these conditions. Furthermore, the contribution of engine starting to these emissions is not negligible; since this operating condition is highly unfavorable for the combustion progress. Additionally, the catalytic converter is ineffective due to the low engine temperature. In conjunction with adequate engine settings (fuel injection and fresh air control), either the glow plugs or the intake air heater are activated during a portion of the engine warm-up period, so that a nominal engine temperatures is reached faster, and the impact of these difficulties is minimized. Measurement of gaseous pollutants during engine warm-up is currently possible with detectors used in standard exhaust gas analyzers (EGA), which have response times well-suited for sampling at such transient conditions. However, these devices are not suitable for the measurement of exhaust emissions produced during extremely short time intervals, such as engine starting. Herein, we present a methodology for the measurement of the cumulative pollutant emissions during the starting phase of passenger car DI Diesel engines, with the goal of overcoming this limitation by taking advantage of standard detectors. In the proposed method, a warm canister is filled with an exhaust gas sample at constant volumetric flow, during a time period that depends on the engine starting time; the gas concentration in the canister is later evaluated with a standard EGA. When compared with direct pollutant measurements performed with a state-of-art EGA, the proposed procedure was found to be more sensitive to combustion changes and provided more reliable data.     

隧道路面温拌硅藻土-SBS复合改性沥青路用性能试验研究

为克服热拌沥青混合料在隧道路面铺筑过程中存在的耗能高、有害气体排放量大的问题,对SBS改性沥青采用降黏剂,降低沥青混合料的拌和、施工温度,然后掺入适量硅藻土.依据正交原理,以针入度、135℃黏度、软化点、延度为评价指标,通过室内试验选择两种性能较优的温拌硅藻土-SBS复合改性沥青,并依据黏温曲线确定加热温度.同时,与S...     

基于无机复合材料的排气管路保温性能研究

重型商用车后处理系统排气管路的保温性能对整车排放性性能有着重要的影响,减小排气管路沿程热损失,提高后处理器内部反应温度和污染物转化效率,是整车实现排放性能升级的重要途径.应用新型无机复合材料包覆排气管路,降低排气管路的热损失,提高后处理器内部化学反应温度,能够有效提升后处理器内部载体的转化能力.在不同的环境温度条件下,...