Saloon Car Engine Fault Diagnosis Based On Virtual Instrument Design And Development Of Teaching System

With the constant development of auto industry, people’s requirement of automobile is becoming higher and higher. All kinds of advanced control theories and methods have been applied to design and develop the new products. Auto control system has become more and more complicated, as a result, the difficulty of failure detection and diagnosis increases. Meanwhile, the requirements of fault diagnosis equipments are increasing. On the base of the investigation in repair factories, the author considers that the traditional diagnostic equipment has a large amount of disadvantages, such as, single function, poor universality, immobility and so on. On the other hand, the pro equipment has a relatively high price, and many repair factories can’t afford it, let alone colleges and universities. The virtual diagnostic equipment could make up for the deficiency of the traditional instrument, and it has great potential. Therefore, as a practitioner in automobile industry, developing a set of the virtual diagnostic equipment has a profound significance.This paper analyzes the recent automobile development in our country firstly, and states the necessity of developing advanced diagnostic equipment and personnel training to achieve the requirements of vehicle maintenance in high-tech era. Then the paper sums up the advantages of the virtual instrument in automobile fault diagnosis and its recent development home and aboard. What’s more, it introduces the component and work principle of the engine electronic control fuel injection system, electronic ignition system control mode and idle speed control strategy, analyzes the formation mechanism of automobile engine fault. Finally the paper explains the design and development methods of car engine fault diagnosis system based on virtual instrument.The hardware design in this system includes the integrated fault test-bed design of Passat1.8T AWL engine ad the selection method of multi-function data acquisition card and PC. The principle of design and selection is to guarantee the effect of training and save the cost, so a scrapped Passat AWL engine is chosen to be the test bench engine, then a personal laptop and the multi-function data collection card NI USB-6218are adopted in the experiment. The software design in the system includes landing, offline simulation diagnosis, online real-time diagnosis and standard data query module. The user could input the correct ID and password to enter the diagnosis main interface. They can choose different ways of diagnosis and also inquire the data they need. This software system has a concise words system; a powerful graphics stereo sense and it’s easy to use. In the system test, the typical sensors and actuators are used, which could analyze the test results in details.