外文翻译 丰田卡罗拉汽车发动机电控喷油系统故障诊断流程设计

译文：
Bhanu Sood,Michael Osterman,Michael Pecht. Tin whisker analysis of Toyota's electronic throttle controls[J]. Circuit World,2011,373.
电控发动机的自诊断系统的作用是监测和诊断发动机的控制系统的工作情况和工作中所出现的故障。

当发动机ECU 检测到来自传感器和执行器的故障信息时，立即将警告灯“CHECK ENGING”点亮，同时将故障信息以故障码的形式存在ECU 中，汽车维修人员可以通过一定的程序将发动机ECU 中的故障码读取，然后根据故障码判别故障的类别和范围。

1.自诊断系统的组成
电控发动机的自诊断系统的组成基本相同，主要有电控单元（ECU）、“CHECK ENGING”警告灯、触发器和显示器件等组成。

其中“CHECK ENGING”警告灯的功能主要是：
a. 检查功能。

当接通点火开关时，警告灯应该点亮。

起动发动机，当转速高于500 r/min 时，警告灯熄灭。

这说明发动机工作无故障。

b. 警告显示功能。

当电控单元（ECU）的任何一个输出、输入信号出现故障时警告灯点亮，告诉驾驶人员电控系统出现了故障。

c. 闪烁输出故障码。

在电控发动机上，储存在存储器中的故障码，通过一定的读取程序输出，有警告灯以闪烁的形式显示出来。

2.自诊断系统的工作原理
电控发动机的控制系统工作时，正常的输入与输出信号都在规定的范围内变化，当某一电路输出的电信号超出规定的范围或电控单元（ECU）不能识别的信号时，电控单元（ECU）就判定为有故障发生。

例如发动机冷却液温度传感器正常工作时，工作温度范围在-30~120 ℃，其输出电压值在0.3~4.7 V 范围内变化。

当水温传感器发生故障（短路或断路）时，冷却液温度传感器给电控单元（ECU）输出的信号电压就会低于0.3 V 或高于4.7 V。

检测到的电压超出了规定范围，因此判定为冷却液温度传感器电路有故障，并以代码（故障码）的形式存储在存储器中。

又如发动机在正常工作中，电控单元在1 min以上检测不到氧传感器输送的信号，或氧传感器输送的信号在1 min 以上在0.3~0.6 V 之间没有发生变化，则判定为氧传感器电路有故障，并以代码（故障码）的形式存储在存储器中。

对执行器进行故障诊断，绝大多数需要增加专用电路来监测执行器的工作情况（信息）。

例如点火系统控制电路中电子点火器的故障自诊断系统。

当点火器回路中的功率三极管不能正常工作时，点火器内的点火监视器就不能得到功率三极管的正常工作信号（不断地导通与截止），因此，点火监视器就不能为电控单元（ECU）提供正常的反馈信号。

如果点火系统发生了故障，此时电控单元（ECU）发出指令，控制喷油器停止喷油。

发动机在正常的工作中，如果偶尔出现一次不正常的信号，电控单元（ECU）自诊断系统不会判定为故障。

只有不正常的信号持续一定的时间或多次出现时，才判定为故障。

例如发动机转速在1 000 r/min时，转速信号失去3~4 个脉冲时，电控单元（ECU）不会判定为故障，“CHECK ENGING” 警告灯不会亮，转速信号不会以故障码的形式存入存储器中。

另外，电控发动机的自诊断系统的故障信号不仅与传感器与执行器的故障有关，而且还与配线电路有关。

因此，在查找故障原因时，除了查找传感器、执行器的故障以外，还要查找线束、插接器以及传感器与电控单元（ECU）之间的有关电路。

3.结束语
通过读取自诊断系统的故障码可以诊断出汽车电控系统的绝大部分故障，随着计算机控制技术的发展和在汽车上的广泛应用，汽车自诊断系统对于电子控制的汽车各大系统故障诊断十分有效，而且非常准确，这是其它任何诊断方法无可比拟的。

因此，作为现代汽车检测与维修技术人员必须掌握电控发动机自诊断系统故障码的读取与清除方法。

原文：
Bhanu Sood,Michael Osterman,Michael Pecht. Tin whisker analysis of Toyota's electronic throttle controls[J]. Circuit World,2011,373.
Self diagnosis system for electronic control engine is the role of the control system fault monitoring and diagnosis of the engine work situation and the work of. When the engine ECU detects the fault information from sensors and actuators, immediately warning lamp "CHECK ENGING" light, while the fault information in fault codes in the form of ECU, vehicle maintenance and repair personnel can be the engine of ECU fault code reading through certain procedures, then according to the category and scope of fault code discrimination fault.
1.self diagnosis system composition
A diagnostic system for electronic control engine is basically the same, mainly electronic control unit (ECU), "CHECK ENGING" warning light, trigger and display etc.. The "CHECK ENGING" warning light is the main function of the:
a. Checking function. When connected to the ignition switch, warning lamp should light up. Start the engine, when the engine speed is higher than 500 r/min, warning lights. This shows that no fault of engine.
b.Warning display function. When the electronic control unit (ECU) of any one output, the input signal failure warning lights, told the driver control system malfunction.
c. Flash output fault code. In the electronic controlled engine, is stored in a memory fault codes, through a certain reading program output, warning lights to flicker is displayed in the form of.
2.Working principle of self diagnosis system
Work of the control system of electronic control engine, input and output signals of normal changes in the specified range, electrical signal when the output of a circuit or beyond the prescribed scope of electronic control unit (ECU) signal can not be identified, the electronic control unit (ECU) is determined as a fault occurs. For example, the engine coolant temperature sensor during normal operation, the operating temperature range at -30~120 ℃, the output voltage changes in the 0.3~4.7 V range. When the water temperature sensor failure (short circuit or open circuit), coolant temperature sensor to the electronic control unit (ECU) signal output voltage will be lower than 0.3 V or greater than 4.7 V. The detected voltage exceeds the specified range, so the decision for the coolant temperature sensor circuit failure, and the code (error code) are stored in the memory. And as the engine in normal operation, the electronic control unit in the above 1 min cannot detect a signal conveying the oxygen sensor, oxygen sensor and signal transmission at 1 min above the 0.3~0.6 V did not change,
then determined for oxygen sensor circuit failure, and the code (error code) are stored in the memory.
For the fault diagnosis of actuator, the vast majority of the need to increase the special circuit to monitor the working condition of the actuator (information). For example, the ignition system control circuit of electronic ignition fault self diagnosis system. When the power transistor ignition circuit in the pipe can not work normally, ignition monitor device can not be normal signal power triode (continuous conduction and cut-off), therefore, the ignition monitor can not for the electronic control unit (ECU) provides a feedback signal to normal. If a failure occurs when the ignition system, electronic control unit (ECU) issued a directive, control fuel injector fuel injection stop.
The engine is in normal work, if occasionally an abnormal signal, the electronic control unit (ECU) for fault self diagnosis system will not judge. Only the signal is not normal for a certain time or several times, only to determine the fault. For example, the engine speed at 1000 r/min, the rotational speed signal loss of 3~4 pulses, the electronic control unit (ECU) will not be judged as fault, "CHECK ENGING" warning light does not light, speed signal not to trouble codes stored in the form of memory.
In addition, fault self diagnosis system for electronic control engine not only faults and sensor and actuator is concerned, but also with the wiring circuit. Therefore, in the cause of failure, in addition to the actuator fault
finding sensor, outside, but also find the wiring harness, connectors and sensors and electronic control unit (ECU) between the relevant circuit.
3.conclusion
By reading the self diagnosis system can diagnose the fault codes of automotive electronic control system of most of the fault, with the development of computer control technology and widely used in automobile, automobile self diagnosis system is effective for electronic control vehicle the system fault diagnosis, and very accurate, this is there is nothing comparable to this any other diagnostic methods. Therefore, as the staff Technology of modern vehicle inspection and repair must master the electronic-controlled engine fault diagnosis system code from reading and clearing method.。