Study And Development Of Engine And Transmission Testing-Control Experimental & Teaching System

Based on the previous automotive testing-control experimental and teaching system, this thesis, has introduced the engine-transmission testing-control experimental and teaching system through the design and development of software and hardware. The system is based on the Nissan Maxima VG30E electronic controlled engine and the RE4F02 automatic transmission. It aims to complete rebuilding its electronic control system, at last designed a set of the experimental, teaching, researching and fault detecting bench without affecting all the electronic controlled engine and automatic transmission performances.Through the signal display and measuring board, signal simulating bench, faults setting bench, and the software platform which is based on the virtual instrumental technology, this system can realize the display and check of the signals from the electronic controlled engine and automatic transmission, the simulation of master signals, the settlement of some usual faults, the display, store, analysis, and reappearance of the waveform and parameter of the signals, the comparison with the standard waveform and the analytical functions of the data stream. And hence, it offers a diagnosing function on the faults. The thesis includes 4 parts, which are as follows:1) Design of the engine and transmission bench. Carefully place the engine, transmission, gear shift lever, accelerator pedal, brake pedal, fuel tank, battery and other instruments into a movable bench in a sequential manner. Be familiar with the system circuit and rewires it.. The designed bench owns great advantages: suitable layout, beautiful sight, flexibility, good dependability, easy ways to operate, effective in experiment and teaching; moreover, it has good independence for it can run alone when disengaging other parts of the system.2) Design of testing-control bench. Design a signal process circuit which can transform the voltage, isolate the signals, shape the form of the signals, magnify the transmitted signals, limit and stabilize the voltage, and switch the circuit; by optimizing the circuitry of the engine and the transmission, it designs a circuit of signal display and check, which realizes the dynamic display and check of the signals; making use of the switch of single-pole double throw switch and the regulation of the potentiometer, it can simulate 4 master signals; designing the modular circuit of the settlement of faults and using AT89C51 SCM, 74LS154 and 74LS249 chip to scan the state of the keystroke of the settlement of faults, it can control the relay of terminal operation, so realizes the settlement of 36 usual faults;3) Design of software which is based on the virtual instrumental technology. Selecting appropriate computer and data acquisition card according to the testing requirement and choosing LabVIEW in reference to the features of the platform of software development, it designs main control module, parameter setting, virtual instruments, start testing, waveform testing, transmission testing, and data processing etc, and realizes the functions of the log-in of the system, the setting of the parameter, virtual instruments, test of the waveforms and the changing trends of the signals from the engine and the transmission in different kinds of working conditions, the comparison between the testing waveform and the standard waveform, the analyses of the data stream, the print of the waveform, the store of the waveform, the process of data after testing and assistance from the system;4) Debugging of the system and the analysis of the tests. Debug each module of software and hardware of the system on the spot which indicates that it has fulfilled the demand of the designed system. Carry on the test of the normal test, the test of simulating signals, the test of settling the faults in the working condition of start, idle speed and acceleration respectively, using the Fluke98 car oscilloscope, the multimeter and related module of the software platform to test data and the waveforms and compare the results of the real instrument and the virtual instrument. The analysis of the result indicates that the system truly reflects the working parameter and the signal waveforms. It fully realizes the dynamic display and check of the signals, the simulation of the signals, the settlement of the faults. The use of the software platform can help a lot in gathering the signals, testing the parameter and the waveforms, and storing and processing of data and the waveforms. Thus, the system fulfills its designed objectives.The result of the trial in the laboratory proves that the system owns great advantages: friendly man-machine interface, easy ways to operate and good dependability, etc. Being able to be applied on different occasions, like experiment, teaching, researching and diagnosing, it turns out to have wide practical value and prospects.