Study On The Key Technologies Of The Environmental Durability Testing System For Automotive Engine ECU

Automotive engine electronic control unit (ECU) is automobile's nerve centre. It precisely controls the engine's ignition timing and fuel injection signals. ECU can greatly enhance automobile's dynamic power, fuel economy and lower tail gas emission. ECU's operation environment is very harsh, and its failure will not only impact the engine's performance, but also endanger the vehicle and drivers'security. So its reliability is very crucial. ECU needs a series of tests to measure and evaluate its environmental durability and reliability during its process of designing and manufacturing, and to provide basis for design improvement and product approval. Presently the domestic and foreign automotive engine ECU testing devices have the defecencies of poor compatibility and extensibility, few testing programs, inconvenient testing strategy establishment, low intelligentization, poor user interface, and so on. And this paper studies the key technologies of automotive engine ECU environmental durability testing system aiming at solving these defecenties.In this paper, the technologies of ECU's reliability and the characteristics of ECU's inputs and outputs are detailedly studied, and the specification of ECU's environmental durability test is established. And the key technologies of generating simulating signals, simulating ECU executors'load, monitoring ECU's operating status, designing the ECU durability testing and managing software, developing the testing system's compatibility and extensibility are also studied in details. On the basis of these, an automotive engine ECU environmental durability testing system is developed successfully. The embedded computer technology and virtual instrument technology are applied in this system. The signal generating subsystem is designed by appling the DDS technology, and it can generate any simulating waves whose frequency, amplitude and phase can be controlled; the status monitoring subsystem can monitor the timing and phase of every ECU's output signals, and judge the ECU's operating status; field bus communication subsystem applies the multiple-layer CAN bus net communication technology, and is compatible with other buses such as K-LINE, GPIB, RS485, and so on. With the SQL Sever as its background, system's testing and managing software manages all the devices in models, establishes ECU reliability testing program combination strategy, and has the functions of scheduling testing programs, diagnosing ECU's failures intellectually, managing the testing data and displaying information, and so on. The key technologies and testing system developed in this paper can simulate an automotive dynamic operating environment, provide all kinds of ECU testing operating modes, collect and record all kinds of ECU's statuses, and record and analyze the failures occurring during the process of testing, at last accomplish the enhancement and evaluation of ECU's reliability level. A type of domestic automotive engine ECU was tested by applying the system and the internal failures and design defects of the ECU were detected. Finally, by improving the design and some other measures, the ECU's reliability level was enhanced significantly and reached the relative standards.