汽车专业毕业设计外文翻译

附录：英汉对照
Automotive oxygen sensor failure and
inspection of the common
The automotive industry is currently in the international application of the sensor on one of the largest markets, and the oxygen sensor reported the number of patents, ranking the first in automotive sensors. Oxygen sensor installed in the vehicle exhaust pipe, use it to detect the oxygen content in exhaust port. Oxygen sensor and thus can be obtained in accordance with the signal, put it back to the control system to
fine-tune the fuel injection, so that A / F control at best, not only greatly reduces emissions and saves energy. At present, the practical application of the oxygen sensor has zirconia dioxide oxygen sensors and the two oxygen sensors. And common oxygen sensor and a single lead, double-lead and lead of three points; single pin for Zirconia oxygen sensor; double lead for the titanium dioxide oxygen sensor;
three-lead type for the heating oxygen zirconia sensors, in principle, lead the way on three of the oxygen sensor is not a substitute for use. Are one of the most widely used type of zirconia oxygen sensor.
First, zirconia oxygen sensor structure
In the use of three-way catalytic converters to reduce exhaust pollution on the engine, oxygen sensors are essential components. Oxygen sensor is located in the first section of the exhaust pipe, catalytic converter at the front. There is a Oxygen Sensor zirconia (a ceramic) components manufacturers, all of its outside has a layer of
thin-plated platinum. Zirconia ceramic plated body at one end with a thin layer of platinum closed. Into the protection of the latter was set, and installed in a metal body. Further protect the protection of the role of sets played and sensor can be installed on the exhaust manifold. Ceramic exhaust external exposure, and the internal atmosphere and the environment the same.
This component has a very high temperature resistance, low temperature so do not allow current through. However, when high temperature, because of the air and exhaust gas oxygen concentration difference, oxygen ions can, through this component. This raises the potential difference, platinum to enlarge. In this way,
air-fuel ratio lower than the theoretical air-fuel ratio (thick), the components in the oxygen sensor in (air) outside (the atmosphere) between the oxygen concentration has a greater bad. Thus, the sensors have a relatively strong one voltage (Johnson V). On the other hand, if the rare gas mixture, air and exhaust gas oxygen concentration difference between the very small, have a sensor, there is only one relatively weak voltage (near 0 volts).
Because once the mixture of air-fuel ratio deviation from the theoretical air-fuel ratio, ternary catalysts for CO, HC and NOX purification capacity will be a sharp decline, it is installed at the exhaust pipe oxygen sensor for detecting oxygen concentration in the exhaust, and ECU the issue of feedback signal, and then by the
ECU to control fuel injection amount of injector change, which will control the mixture at the air-fuel ratio near the theoretical value.
Two, automotive oxygen sensor working principle
Oxygen sensor installed in the exhaust manifold, it can detect the concentration of oxygen in the exhaust, air-fuel ratio calculated, and the results sent to the ECU.
For example:
1, exhaust gas oxygen concentration in the high –
When emissions are significant when the percentage of oxygen, ECU will accordingly determine the air-fuel ratio, and that is very dilute mixture.
2, exhaust gas oxygen concentration in the low –
When the percentage of oxygen in the exhaust very, ECU to determine air-fuel ratio will accordingly small, that is very strong mixture. Temperature higher than
300 ℃, the ceramic materials used for the iron conductor. Under these conditions, if the percentage of oxygen sensors on both sides of the different content will have a voltage change at both ends. Two types of environment (air-side and exhaust side) of the different measurements of the oxygen content of these changes tell ECU, exhaust at the oxygen content in the remainder of the generation of harmful emissions to ensure that combustion is not appropriate percentage. Ceramic materials at temperatures lower than 300 ℃are non-linear, and thus the sensor is not a useful signal transmission. ECU has a special function, that is, heating machine at pm (open-loop operation) to stop the adjustment of the mixture. Sensors equipped with heating elements to reach operating temperature quickly. When current flows through the heating elements, it reduces the iron to make ceramics become conductors of time, and which makes the sensor can be installed in the exhaust pipe of the site later.
In the three-way catalytic purifier Medium, ECU using data from the oxygen sensor to regulate the air-fuel ratio, but the method of standard Carburetor EFI device somewhat different.
At EFI device, EFI's ECU fuel injection through the increase or decrease from the injected fuel volume, adjusting air-fuel ratio. If the ECU from the oxygen sensor detects the mixture too thick, it will gradually reduce the amount of fuel injection, the mixture of on-thinning. Therefore the actual air-fuel ratio becomes greater than the theoretical air-fuel ratio (more dilute). When this happens, ECU through the oxygen sensor to detect the truth, it will start a gradual increase in the volume of spray. In this way, air-fuel ratio is too low, some will Luan (more dense) until the air-fuel ratio lower than the theoretical. Thus, the cycle repeated, ECU main cloud in this way, constant changes in air-fuel ratio, the actual air-fuel ratio near the theoretical air-fuel ratio.
Carburetor in the use of the device, are entered by regulating air intake air-fuel ratio of air-conditioning. Mixture theory is usually air-fuel ratio to maintain a little thick. ECU within the air-fuel ratio oxygen sensor has been the information, and manipulation, according to the actual air-fuel ratio EBCU (electronically controlled intake valve) regulator into the carburetor air intake volume. If mixture is too strong, it allows more air to enter to-thinning: If mixture is too thin, it allows less air to enter,
so that more
Third, the common automotive oxygen sensor fault
Once the oxygen sensor fails, the electronic fuel injection system will enable the computer should not be the oxygen concentration in the exhaust pipe of the information, and therefore should not be on the air-fuel ratio feedback control, the engine will increase fuel consumption and exhaust pollution, engine idle speed instability, lack of fire, such as fault-surge situation. Therefore, it is necessary to troubleshoot in a timely manner or replaced.
1, oxygen sensor poisoning
Oxygen sensor poisoning and are often more difficult to control emerging as a fault, in particular, are often the use of leaded petrol cars, even the new oxygen sensor, and can only be the work of thousands of kilometers. If only minor lead poisoning, and then use a box of unleaded petrol, will be able to eliminate the surface of oxygen sensor lead to the resumption of normal work. But often because of excessive exhaust temperature, which lead intrusion in their internal and impede the spread of oxygen ions to oxygen sensor failure can only be replaced at this time.
In addition, the oxygen sensor silicon poisoning happened is common. In general, gasoline and lubricants containing silicon compounds generated by combustion silica, silicon rubber seal gasket improper use of silicone emitting gas,
will cause the oxygen sensor failure, and therefore want to use good quality fuel and lubricants .Right to choose the repair and installation of rubber gaskets, coated on the sensor not to require the use of factory and other than the anti-solvent, etc.
2, carbon deposition
Not because of engine combustion, in the carbon deposition formed on the surface of oxygen sensor, oxygen sensor or the internal into the sediment, such as oil or dust will impede or block the external air into the oxygen sensor internal to oxygen sensor signal output inaccurate, ECU should not timely correct air-fuel ratio. Soot produced, mainly for increased fuel consumption, emission levels were significantly increased. At this point, if the sediment removal will restore normal working.
3, oxygen sensor ceramic fragments
Ceramic oxygen sensor hardware and crisp, with a hard object by knocking or washing with a strong air currents blowing all its fragmentation and possible failure. Therefore, be particularly careful when handling and found that the timely replacement of problem.
4, heater resistance wire blown
The heating-type oxygen sensor, if the resistance heater wire ablation, it is difficult to make sensors to reach normal operating temperature and the loss of role.
5, oxygen sensor breaking off the internal circuits.
Four, automotive oxygen sensor method
1, oxygen sensor heater resistance check
Unplug the oxygen sensor wiring harness plug, use a multimeter resistance measurement file in the oxygen sensor heater terminal access-chu-chu with Ground between access resistance and its resistance to 4-40Ω (refer to specific model
specification). Such as not meeting the standard, should be the replacement of oxygen sensor.
2, oxygen sensor voltage feedback measurement
Measurement of oxygen sensor feedback voltage should unplug the oxygen sensor wiring harness plug, the control circuit models, the feedback from the oxygen sensor voltage output terminal on a thin wire leads, and then plug harness plugs well, in the engine operation , measured from the pinout on the feedback voltage (some models can also be inner socket fault detection by a voltage of oxygen sensor feedback, such as the production of Toyota cars can be a series of fault detection from the socket terminal OX1 or OX2 directly measured oxygen sensor feedback voltage). Oxygen sensor feedback on the test voltage, it is best to use with low-range (typically 2V) and high impedance (resistance greater than 10MΩ) multimeter pointer type. Detection of specific methods are as follows: 1) hot cars engine to normal operating temperature (or after the start-up speed of 2500r/min running 2min); 2) will file a negative voltage multimeter table T then fault detection within the socket or the battery negative electrode E1 is fault detection table T then the socket jack OX1 or OX2, or receive oxygen sensor wiring harness plug on the No. | round; 3) to allow the engine to maintain speed around 2500r/min operation voltage meter at the same time check whether the pointer back and forth between 0-1V swing, with a note of voltage meter pointer 10s the number of swing. Under normal circumstances, with the feedback control, the oxygen sensor feedback voltage will be 0.45V at changing up and down, 10s in the number of feedback voltage changes should not be less than 8 times. If less than 8 times, then oxygen sensor feedback control system or not working properly because the surface of oxygen sensor are possible there is carbon deposition, so that lower sensitivity. In this regard, should be allowed to 2500r/min engine speed operation of about 2min, to clear the surface of the carbon deposition oxygen sensor, and then check the feedback voltage. If the removal of carbon deposition may change after the voltage meter pointer is still slow, then oxygen sensor damaged, or have computer feedback control circuit fault. 4) check whether the damaged oxygen sensor Unplug the oxygen sensor wiring harness plug, so that oxygen sensor is no longer connected with the computer, feedback control system is in a state of
open-loop control. The multimeter voltage pen table file is directly related to oxygen sensor feedback voltage output terminal connected to the negative form of good Ground pen. Measurement of engine operation at the feedback voltage, the first intake pipe was torn off and then up at the mandatory crankcase ventilation hose vacuum tube or other artificially dilute the mixture to form, at the same time watch voltage meter, the pointer should be dropped readings. Was torn off and then connected to the pipeline, and then unplug the water temperature sensor connector, a 4-8KΩ in place of the resistance temperature sensor, the formation of artificially dense mixture, at the same time watch voltage meter, the indicator reading should be increased. Can also be used, or a sudden release the accelerator pedal down approach to change the concentration of the mixture, in sudden pedal down to accelerate, the mixture变浓, feedback voltage should be increased; sudden release when the accelerator pedal,
mixed gas-thinning, feedback voltage should be decreased. If the oxygen sensor feedback voltage without the above changes show that the oxygen sensor has been damaged. In addition, the titanium dioxide-type oxygen sensor using the above method at the time, if a good oxygen sensor output voltage to 2.5V as the center should be up and down fluctuations. Otherwise, the sensor can be removed and exposed to the air, cooling the resistance value after the measurement. If a large resistance value that sensor is ok, or should replace the sensor. 5) oxygen sensor to check the color appearance Removed from the exhaust pipe on oxygen sensors, sensors to check whether the shell to plug up the vents, ceramic core whether or not broken. If damaged, replace the oxygen sensor should be. By observing the top part of the oxygen sensor can also determine the color breakdown:
①light gray top: This is the normal color of the oxygen sensor; ②white top: pollution from silicon, oxygen sensor must be replaced at this time; ③brown top: pollution by lead, if serious, we must replace the oxygen sensor; ④black top: caused by carbon deposition, carbon deposition in the exclusion of engine failure, the general oxygen sensor can automatically clear up the accumulated
carbon. Conclusion: for energy conservation and the prevention of pollution from motor vehicles, most developed countries in the West aerobic sensors installed on my car is loaded oxygen sensor must be used. China's automobile industry with foreign countries, one of the main gap, but also in automotive sensors. Therefore, we can come to promote the use of oxygen sensor is very optimistic about the prospects.
汽车氧传感器的常见故障及检查
汽车行业是目前在国际上应用传感器最大的市场之一,而氧传感器申报的专利数,居汽车传感器的首位。

氧传感器装在汽车排气管道内，用它来检测废气口的氧含量。

因而可根据氧传感器所得到的信号，把它反馈到控制系统，来微调燃料的喷射量，使A/F控制在最佳状态，既大大地降低了排污量，又节省了能源。

目前，实际应用的氧传感器有氧化锆式氧传感器和氧化钛式氧传感器两种。

而常见的氧传感器又有单引线、双引线和三根引线之分，；单引线的为氧化锆式氧传感器；双引线的为氧化钛式氧传感器；三根引线的为加热型氧化锆式氧传感器，原则上三种引线方式的氧传感器是不能替代使用的。

其中应用最多的是氧化锆式氧传感器。

一、氧化锆式氧传感器的构造
在使用三元催化转换器以减少排气污染的发动机上，氧传感器是必不可少的元件。

氧传感器位于排气管的第一节，在催化转化器的前面。

氧传感器有个二氧化锆（一种陶瓷）制造的元件，其里外都镀有一层很薄的白金。

陶瓷化锆体在一端用镀薄铂层来封闭。

后者被插到保护套中，并安装在一个金属体内。

保护套起到进一步保护作用并使传感器得以安装到排气歧管上。

陶瓷体外部暴露在排气中，而内部与环境大气相通。

这个元件低温时有很高的电阻，所以温度低时不允许电流通过。

但高温时，由于空气中和废气中氧的浓度差异，氧离子却能通过这个元件。

这就产生了电位差，白金将其放大。

这样，空燃比低于理论空燃比（较浓）时，在氧传感器元件内（废气）外（大气）之间有较大的氧气浓度差。

于是，传感器产生一相对较强的电压（约翰逊伏）。

另一方面，如果混合气稀，大气和废气之间氧浓度差很小，传感器也就只产生一相对较弱的电压（接近0伏）。

由于混合气的空燃比一旦偏离理论空燃比，三元催化剂对CO、HC和NOX的净化能力将急剧下降，故在排气管中安装氧传感器，用以检测排气中氧的浓度，并向ECU发出反馈信号，再由ECU控制喷油器喷油量的增减，从而将混合气的空燃比控制在理论值附近。

二、汽车氧传感器的工作原理
氧传感器安装在排气歧管上，它可以检测废气中的氧气浓度，据此计算空燃比，并将结果传送到ECU。

例如：
1、废气中氧气浓度高
当废气中氧气的百分比很大时，ECU将据此判定空燃比大，即混合气很稀。

2、废气中氧气浓度低
当废气中氧气的百分比很小时，ECU将据此判定空燃比小，即混合气很浓。

温度高于300℃时，所采用的陶瓷材料，用作氧化铁的导体。

在此条件下，如果传感器两侧氧的百分比含量不同，就会在两端产生电压变化。

两种环境（空气侧和排气侧）中不同含氧量的测量值的这种变化告诉ECU，在排气中剩余的氧含量，对保证燃烧有害废气生成是不合适的百分比。

陶瓷材料在低于300℃温度时是非线性的，因而传感器不输送有用信号。

ECU有一个特殊功能，即在暧机时（开环运转）停止对混合气的调整。

传感器装有加热元件以尽快达到工作温度。

当电流流过加热元件时，它缩短了使陶瓷成为铁的导体的时间，而且使得传感器可以装在排气管较后的部位。

在三元催化净化器中，ECU利用来自氧传感器的数据，调节空燃比，但其方法 EFI装置各标准化油器多少有些不同。

在EFI装置中，EFI的ECU通过增减从喷油喷入气缸的燃油量，调节空燃比。

如果ECU从氧传感器检测到混合气太浓，就会逐渐减少燃油喷射量，于是混合气就变稀了。

实际空燃比因此变得比理论空燃比大些（稀些）。

发生这种情况时，ECU通过氧传感器测出这个事实，就会开始逐渐增加喷射量。

这样，空燃比就会娈得低些（浓些）直到低于理论空燃比。

于是，这样循环反复，ECU主浊以这种方式，不断地增减空燃比，使实际空燃比接近理论空燃比。

在使用化油器的装置中，是用调节进入进气口的空气量调节空燃比。

混合气通常保持略浓理论空燃比。

ECU内氧传感器不断得到空燃比的信息，并要据实际空燃比操纵EBCU（电控进气阀）调节进入化油器进气口的空气量。

如果混合气太浓，就允许较多空气进入，使其变稀：如果混合气太稀，就允许较少空气进入，使其变浓些。

三、汽车氧传感器的常见故障
氧传感器一旦出现故障，将使电子燃油喷射系统的电脑不能得到排气管中氧浓度的信息，因而不能对空燃比进行反馈控制，会使发动机油耗和排气污染增加，发动机出现怠速不稳、缺火、喘振等故障现象。

因此，必须及时地排除故障或更换。

1、氧传感器中毒
氧传感器中毒是经常出现的且较难防治的一种故障，尤其是经常使用含铅汽油的汽车，即使是新的氧传感器，也只能工作几千公里。

如果只是轻微的铅中毒，接着使用一箱不含铅的汽油，就能消除氧传感器表面的铅，使其恢复正常工作。

但往往由于过高的排气温度，而使铅侵入其内部，阻碍了氧离子的扩散，使氧传感器失效，这时就只能更换了。

另外，氧传感器发生硅中毒也是常有的事。

一般来说，汽油和润滑油中含有的硅化合物燃烧后生成的二氧化硅，硅橡胶密封垫圈使用不当散发出的有机硅气体，都会使氧传感器失效，因而要使用质量好的燃油和润滑油。

修理时要正确选用和安装橡胶垫圈，不要在传感器上涂敷制造厂规定使用以外的溶剂和防粘剂等
2、积碳
由于发动机燃烧不好，在氧传感器表面形成积碳，或氧传感器内部进入了油污或尘埃等沉积物，会阻碍或阻塞外部空气进入氧传感器内部，使氧传感器输出的信号失准，ECU不能及时地修正空燃比。

产生积碳，主要表现为油耗上升，排放浓度明显增加。

此时，若将沉积物清除，就会恢复正常工作。

3、氧传感器陶瓷碎裂
氧传感器的陶瓷硬而脆，用硬物敲击或用强烈气流吹洗，都可能使其碎裂而失效。

因此，处理时要特别小心，发现问题及时更换。

4、加热器电阻丝烧断
对于加热型氧传感器，如果加热器电阻丝烧蚀，就很难使传感器达到正常的工作温度而失去作用。

5、氧传感器内部线路断脱。

四、汽车氧气传感器的检查方法
1、氧传感器加热器电阻的检查
拔下氧传感器线束插头，用万用表电阻档测量氧传感器接线端中加热器接柱
与搭铁接柱之间的电阻，其阻值为4-40Ω( 参考具体车型说明书)。

如不符合标准，应更换氧传感器。

2、氧传感器反馈电压的测量
测量氧传感器的反馈电压时，应拔下氧传感器的线束插头，对照车型的电路图，从氧传感器的反馈电压输出接线柱上引出一条细导线，然后插好线束插头，在发动机运转中，从引出线上测出反馈电压(有些车型也可以由故障检测插座内测得氧传感器的反馈电压，如丰田汽车公司生产的系列轿车都可以从故障检测插座内的OX1或OX2端子内直接测得氧传感器的反馈电压)。

对氧传感器的反馈电压进行检测时，最好使用具有低量程(通常为2V)和高阻抗(内阻大于10MΩ)的指针型万用表。

具体的检测方法如下：
1)将发动机热车至正常工作温度(或起动后以2500r/min的转速运转2min)；
2)将万用表电压档的负表笔接故障检测插座内的E1或蓄电池负极，正表笔接故障检测插座内的OX1或OX2插孔，或接氧传感器线束插头上的号|出线；
3)让发动机以2500r/min左右的转速保持运转，同时检查电压表指针能否在0-1V之间来回摆动，记下10s内电压表指针摆动的次数。

在正常情况下，随着反馈控制的进行，氧传感器的反馈电压将在0.45V上下不断变化，10s内反馈电压的变化次数应不少于8次。

如果少于8次，则说明氧传感器或反馈控制系统工作不正常，其原因可能是氧传感器表面有积碳，使灵敏度降低所致。

对此，应让发动机以2500r/min的转速运转约2min，以清除氧传感器表面的积碳，然后再检查反馈电压。

如果在清除积碳可后电压表指针变化依旧缓慢，则说明氧传感器损坏，或电脑反馈控制电路有故障。

4）检查氧传感器有无损坏
拔下氧传感器的线束插头，使氧传感器不再与电脑连接，反馈控制系统处于开环控制状态。

将万用表电压档的正表笔直接与氧传感器反馈电压输出接线柱连接，负表笔良好搭铁。

在发动机运转中测量反馈电压，先脱开接在进气管上的曲轴箱强制通风管或其他真空软管，人为地形成稀混合气，同时观看电压表，其指针读数应下降。

然后接上脱开的管路，再拔下水温传感器接头，用一个4-8KΩ的电阻代替水温传感器，人为地形成浓混合气，同时观看电压表，其指针读数应上升。

也可以用突然踩下或松开加速踏板的方法来改变混合气的浓度，在突然踩下加速踏板时，混合气变浓，反馈电压应上升；突然松开加速踏板时，混合气变稀，反馈电压应下降。

如果氧传感器的反馈电压无上述变化，表明氧传感器已损坏。

另外，氧化钛式氧传感器在采用上述方法检测时，若是良好的氧传感器，输出端的电压应以2.5V为中心上下波动。

否则可拆下传感器并暴露在空气中，冷却后测量其电阻值。

若电阻值很大，说明传感器是好的，否则应更换传感器。

5)氧传感器外观颜色的检查
从排气管上拆下氧传感器，检查传感器外壳上的通气孔有无堵塞，陶瓷芯有无破损。

如有破损，则应更换氧传感器。

通过观察氧传感器顶尖部位的颜色也可以判断故障：
①淡灰色顶尖：这是氧传感器的正常颜色；
②白色顶尖：由硅污染造成的，此时必须更换氧传感器；
③棕色顶尖：由铅污染造成的，如果严重，也必须更换氧传感器；
④黑色顶尖：由积碳造成的，在排除发动机积碳故障后，一般可以自动清除
氧传感器上的积碳。

结束语：为了节能和防止汽车污染，西方发达国家大都装有氧传感器，对我国来说装汽车用氧传感器势在必行。

我国汽车工业同国外的主要差距之一，也表现在汽车传感器方面。

因此，可得出氧传感器推广应用的前景十分乐观。