The Theory And Method For Automobile Engine Fault Diagnosis

Engines are the main assembly of motor vehicles, are important power sources for vehicles. With its continuous improvement of working performance and the level of automation, vehicles'structures also becoming more and more complicated, moreover, extremely poor working conditions increase engine failure incidence, which means that, also increase the difficulty to fault diagnosis. So the probability of engine failure is also growing, that lead to more difficult of its diagnosis. This makes automotive engine to be the important object of fault diagnosis and detection. With the rapid development of computer and software technology, the degree of modern automotive electronics continues to improve greatly, not only optimized vehicle performance greatly, but also complicated the vehicle control system's structure and function. However, once the control system took place fault diagnosis and repair has become more difficult, there will be higher demand to maintenance man's knowledge and experience. With the reason that diagnosis of fault position rapidly and improve the efficiency of repair, automotive companies and research institutions which from all over the world have invested substantial funds and energy on the fault diagnosis research about electric automobile engine control system. Whilst automobile industry have just developed compared with the developed countries, automotive electronics industry lags far behind them, therefore the research about car fault diagnosis method is benefit to improve and enhance our country's automotive diagnostic techniques, as well as it has important practical significanc.Automotive engine fault diagnosis theory and method gradually improved with the continuous process of automotive technology. Set up a scientific, systematic, rational, comprehensive system for automotive fault diagnosis theory has become an inevitable requirement and an inevitable technological development trend to the car fault diagnosis. At present, however, there are many different types methods about the engine fault self-diagnosis system design, but many of them are varied and messy, there still blank in a detailed discussion at the implementation of their respective, except that general comparison of the advantages and disadvantages of different methods in this field, the purpose of this paper is to fill this blank, not only with a high theoretical value, but also easy to consult.This paper made clear and basic definition of fault diagnosis, and then leads to the concept and flow about engine fault diagnosis. Moreover, synthesize the research status at home and abroad of engine fault self-diagnosis, existing problems and future trends. Subsequently, there is an in-depth discussion about mainly testing and diagnostic methods in EFI engine fault diagnosis (based on signal processing methods, the analytical model, and knowledge-based fault diagnosis method). First and foremost, based on signal processing methods to conduct a detailed analysis, focusing on the wavelet theory and give an example of fault diagnosis to these theories. In the second place, the analytical model based on the introduction of the method, discussed in detail that the methods of their classification as well as lack of implementation and the proposed. Additionally, introduce the knowledge-based method of fault diagnosis then based on signal processing methods to conduct a detailed classification analysis, and combination of the above-mentioned theory a real example is given, which based on neural network expert system for fault diagnosis.Furthermore, the use of fault diagnosis methods and virtual instrument combining virtual instrumentation based on the introduction Engine Fault self-diagnosis systems; on the other hand, introduce the basic components of engine remote diagnosis system, analysis the structure of the remote diagnosis center, focus on the fault Reasoning System, both the two sides are based on the fault diagnosis technology and modern network technology.