Study On The Examining System Of Comprehensive Performance Of Diesel Engine Based On Virtual Instrument

Since 1970's, with the development of computer and micro-electronics technology, the fields of measurement and instrument technology has been advanced greatly. As a new developing technology, Virtual instrument is attracting more and more attentions in measurement and control field. It has broken through the traditional instruments conception to some extent. With the intervention of computer technology and micro-electronics technology into the area of measurement and instrument, measurement technique and computer technology's combination results a scene of revolution. A new instrument conception may produce a new generation of instruments. Virtual instrument becomes a focus and a promising research point. It brings the measurement technology to a new age. At the same time, diesel engine is widely used in heavy duty vehicles and machines for its huge power, economic and safety. With the using of turbocharger technology and high-pressure common rail technology, noise and exhaust standard is improved. Engine is the important part of vehicles, so it is important to find out performance of engine, so as to measure the performance of vehicle. In this paper, the application of virtual instrument technology and the sensor technology to realize engine performance parameters' rapid measure and data processing has been studied. This paper also has developed an engine examination method and enlarged the virtual instrument application area. The main research content in this paper is as following:(1) This research analyzed the diesel engine development trend in detail, and discussed the questions about the current diesel engine and the examination method. Compared with the traditional instrument, virtual instrument' merit factors include lower cost of exploitation and maintenance, shorter period of technical update, more flexibility and so on. Software plays a key role in the instrument, and it keeps synchronizing with computer technology. Taking the virtual instrument as an examination platform of the engine performance measure is an economic, flexible, and suitable choice.(2) The research has analyzed the diesel engine performance characteristic parameters and the measurement principles. Unified sensor technology, signal processing technology and virtual instrument technology, It has developed the diesel engine performance virtual instrument measurement system by using the Lab VIEW software. This is a highly integrated system, combined the data acquisition card (DAQPad-6020E), sensors and the corresponding software. It is possible to measure some parameters and to analysis the data at the same time. It has the same function as traditional performance measure instrument, and using computingpower of computer. Therefore, it is possible to realize fault analysis and intelligent diagnosis function.(3) In view of the characters of diesel engine performance examination instrument, the virtual instrument system is realized with a hierarchical structure. The measure system includes 6 modules: power measure module, high pressure injection parameter measure and the analysis module, engine starting parameter examination module, intake manifold vacuum degree test module and the exhaust analysis module. The system structure is clear, highly readable and extensible. And the software program is easy debugging.(4) The system used different sensors to examine high-pressure fuel wave, the intake manifold vacuum degree wave and the start engine current wave. By using the mathematics method of correlation analysis, Fourier transforms, power spectrum analysis and the wavelet analysis, the neural network with the calculating engine of MATLAB, the wave data provide the essential information for the engine performance evaluation and the fault diagnosis.(5) By using DataSocket and Web Server technology, measure and control based on network could be easily realized. The instrument will be more and more intelligent and standard. The combination of the network technology and the virtual instrument technology to build virtual instrument system based on network is the developing direction of virtual instrument system.