| This thesis has developed a testing-control experimental and teaching system of SOFIM8140.43S3common rail diesel engine based on the virtual instrument technology. Be familiar with the electronic control system of SOFIM8140.43S3common rail diesel engine, It aimed to complete rebuilding its electronic control system, at last designed a set of the experimental, teaching, researching and fault detecting bench without affecting the engine performances.Through the monitoring and control board, signal simulation module, faults setting board and the software platform which is based on the virtual instrumental technology, this system can realize display and check of signals from the common rail diesel engine, simulation of the master signals, settlement of some usual faults, display, store, analysis, and reappearance of the waveform and parameters of signals and data flow analysis. Besides, it offers fault detection capabilities. The main content of this thesis are shown as follow:1) Design of the engine bench. Carefully place the engine, intercooler, accelerator pedal and other instruments into a movable bench in a sequential manner. Be familiar with the engine circuits and rewired it. The designed bench owns great advantages:suitable layout, beautiful sight, flexibility, good dependability, easy to operate, effective in experiment and teaching.2) Design of monitoring and control board. Signal processing circuit has been designed, its functions includes voltage conversion, signal isolation, signal shaping, signal amplification and pressure limitation and so on. Engine circuits had been optimized, dynamic display and check of signals had been realized. Faults setting board has been designed, and the common faults setting had been realized by using a group of switches to control27wires directly.3) Development of software based on the virtual instrumental technology. Selecting appropriate computer and data acquisition card according to the testing requirement and choosing Lab VIEW in reference to the features of the platform of software development. Login module, main control module, virtual instruments, start testing, waveform testing, data processing and signal simulating etc. have been designed and functions such as log-in of the system, virtual instruments, test of the waveforms and its changing trends of signals from the engine in different kinds of working conditions, signal simulation, analyses of the data stream, print of the waveform, store of the waveform, the process of data after testing and system assistance had been realized.4) Debugging of the system and test analysis. Each module of software and hardware of the system had been debugged on the spot and it indicates that the system operates normally and reliably and can meet the design requirements. Normal test, test of simulating signals, test of settling faults in the working condition of start, idle speed and acceleration had been carried on respectively. Signal data and waveforms can be tested through using oscilloscope, multimeter and the related module of the software platform. Comparing the results of the real instrument and the virtual instrument, the results indicated that system can truly reflects the working parameter and the signal waveforms and fully realizes the dynamic display and check of the signals, the simulation of the signals and faults setting. The software platform can realize collection of signals, test and display of parameter and waveforms, store of data and waveforms, print and process etc. Thus, the system fulfills its design objectives both in software and hardware. |
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