The so-called automobile fault diagnosis technology is mainly based on the relevant theories of automobile and internal combustion engine, combined with the diagnosis of automobile fault as a theoretical guide, and through the analysis and mastery of the structural principle and computer control technology of automobile and internal combustion engine, the working efficiency is continuously improved. Intelligent automobile diagnosis plays a very important role in the development of automobile fault diagnosis technology. It needs the help of high and new technologies such as computer technology and sensing technology, and pays attention to the accurate analysis of information and data to provide guarantee for technical development.
1 basic diagnosis technology of automobile fault
1. 1 manual detection and diagnosis technology
Judging from the current development, automobile fault monitoring and maintenance in small and medium-sized cities are mainly intuitive diagnosis made by staff with their work experience. However, the premise of its work is that skilled workers have enough knowledge to master the automobile structure and operation principle, and realize the continuous accumulation of their diagnosis experience through the improvement of fault diagnosis skills and automobile fault maintenance skills. According to the current survey, almost every automobile maintenance company will be equipped with experienced maintenance personnel for fault detection. Automobile fault detection based on manual experience is actually a primitive skill, which is in danger of being replaced by modern high-tech detection technology. In the process of automobile diagnosis, manual fault diagnosis technology is used, and experienced professionals can locate the fault parts through the feedback of the owner and the monitoring of automobile faults. Among them, the methods of manual fault monitoring mainly include: road test drive, sensory detection with the help of hearing, smell and touch, direct observation of faults, simulation experiments, sectional inspection and so on. Because of its flexibility, this detection method has a very wide range of applications. However, the manual fault detection method also has some limitations, and its detection accuracy is directly linked to the actual work experience and working ability of relevant maintenance personnel, but there is a limited number of senior maintenance personnel at present.
1.2 computer fault diagnosis technology
The so-called computer fault diagnosis technology is mainly supported by a decoder. The decoder is actually equivalent to a microcomputer, which has functions that cannot be realized by manual diagnosis and detection. By extracting the relevant information stored in EC U, the information can be sorted out and then processed by special software. Finally, through the information conveyed by words or line charts, the staff can locate according to the information summarized on the screen. If the decoder doesn't really display its fault code, or the technician can't detect its fault according to the displayed data, the technician needs to delimit the scope according to the actual situation reflected by the owner, then investigate the performance of the components, and finally determine the actual part of the fault by troubleshooting. In addition, the decoder can also use the sound quality of automobile computers for dynamic and static fault monitoring and diagnosis. Judging from the current development, computer fault diagnosis technology has been widely used in first-and second-tier cities in China, and has been recognized by professionals to a certain extent, which has a very broad development space.
1.3 instrument fault diagnosis technology
With the development in recent years, the continuous improvement of people's living standards and the continuous improvement of travel quality requirements, China's automobile industry has undergone tremendous changes. With the development of information and related electronic space technology, electronic control unit, as an important part of modern automobile structure, needs to master its internal structure to realize the difficulty of automobile fault diagnosis. In order to improve the requirements of detection technology, relevant technicians need to adopt scientific instrument fault diagnosis technology to monitor the parameter values and maintain and deal with them by judging the fault parts. Technical maintenance personnel can use multimeter, current probe and other fault diagnosis instruments to obtain data stream, and relevant technicians need to compare the obtained values with the standard values to realize the grasp of fault diagnosis position. Oscilloscope and multimeter, as commonly used important instruments, have similar functions, and can be eliminated by measuring voltage value, resistance value and signal pulse width. However, the current probe only monitors the signal values of AC and DC currents, and these fault detection instruments cannot be carried out under their existing working conditions. Because of their strong limitations, the accuracy of fault judgment is greatly affected, and the positioning is prone to deviation, which is also a major problem that hinders the instrument fault diagnosis technology.
2 Modern automobile fault diagnosis application technology
2. 1 OBDII system
The so-called O B D II system is an advanced auto fault detection system. Through the loading of O B D II fault detection system, its data network communication is based on the electronic control system. The so-called class B data network structure mainly realizes information transmission through the combination of application layer, physical layer and data link layer, and finally realizes the effective communication between O B D II system and relevant detection equipment under the vehicle, and ensures the smooth communication process through the compliance of relevant protocols.
2.2 On-board self-diagnosis technology
In modern automobile fault diagnosis, a very important part is the on-board self-diagnosis technology, which is also the mainstream fault diagnosis technology today. However, its development also has some limitations. For example, its own technical equipment can not accurately detect the value of automobile exhaust emissions, but can only play a supervisory role; In addition, the actual authenticity of the value of self-diagnosis technology is questionable, and the monitoring results are influenced by external objective environment. In a word, the on-board self-diagnosis technology can only help to monitor the fault parts of the car, but has no influence on the methods and steps of its maintenance. This requires continuous improvement of relevant diagnosis technologies, and through the continuous improvement of diagnosis methods, the most accurate information can be provided for the fault parts.
3 Conclusion
With the continuous development of diagnostic equipment, China's automobile fault diagnosis technology has developed rapidly. Compared with the development of foreign countries, there is still a big gap in China's automobile diagnosis technology. With the continuous development of high-tech industry and the continuous progress of national economy, fault detection and diagnosis technology in China has developed rapidly. Therefore, it is necessary to grasp the development of automobile fault diagnosis technology, realize the establishment of excellent diagnosis ideas through the cooperation of R&D personnel and maintenance personnel, and then form scientific, efficient and practical diagnosis equipment, and finally improve the automobile fault diagnosis technology in China.
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