Engine And Control System Based On Virtual Instrument Development

The engine is the heart of all power equipment, and the working condition of the device depends on the stability of the engine. So monitoring the engine is very necessary. In this paper, the author analyzed the status of development about engine testing system at home and abroad, and recognizes that with the development of computer technology, the engine testing and controlling system become more and more roboticized, intelligent and functional. And it will become an important development direction that Virtual Instrument use in engine testing. This issue designed engine testing and controlling system by using NI's Lab VIEW (graphical programming software), which is based on the Engine-Electric Eddy Current Dynamometer, and accompanied by a variety of sensors and intelligent instruments. The system is highly automated and has the better scalability and stability.The design idea of this system is that the overall structure was designed in distribute conception, and the software was designed in structured and modular conception. This paper mainly describes the design of hardware and software of engine testing and controlling system, as follow:Firstly, general parameters testing of engine is introduced. This paper discuss the test methods of every parameters and hardware devices (including sensors, instrumentations, etc.), and present speed, power and torque measurements in detail. The interface of the system designed by Lab VIEW, which has functions of data processing, parameter display, data storage, rendering curves and so on.Secondly, the engine vibration testing system is introduced in details. Analyzing vibration source of engine, describing the signal processing, the system analyzed vibration signal in time domain analysis, frequency domain analysis and time-frequency analysis by using the Advanced Analyze Library of LabVIEW. Designed vibration testing software can save the test image analysis.Thirdly, the design for hardware and software of serial port expansion by using microcomputer is introduced. The design used SP3739 serial port expansion chip, and use time division multiplex access technology expanding a full-duplex serial port into seven fully independent full-duplex serial port, thus solving simultaneous control problem of smoke meter, noise meter, NO analyzer monitoring in this system.Finally, the engine control model is studied. The author analyzes the existing two-loop PID control; and then design a fuzzy PID controller, built simulation model in the Simulink environment, and complete simulation engine speed control.When system design accomplished, the author conducted various parameters test and vibration test, and achieved satisfactory results, which further proved that the design of the whole system is successful.