Research On The Integrated Measuring System Of Marine Diesel Engine Based On Virtual Instruments

Because the ship diesel engine complicated structure, poor working conditions, it is the key to the operation of the ship monitoring systems. With the high development of microelectronic technology, computer technology, software technology and network technology, combining the test technology and computer technology , it is causing a revolution in the field of testing instrument, virtual instrument based on computer software technology as the core is a new development direction of measurement and control field. The virtual instrument technology and the diesel engine testing combined,monitoring and analysis of the comprehensive performance of the diesel engine parameters is realized in the platform of virtual instrument technology. In this paper,virtual instrument technology is applied in the testing and monitoring of marine diesel engine. This paper mainly studied the following aspects.Based on the study of diesel engine feature parameters and measuring principle, combined with sensor technology and signal processing technology, the integrated monitoring system of diesel engine designed by using virtual instrument technology. In terms of hardware,according to various parameters of the signal of diesel engine running in, designed the signal measurement and processing method. This paper gives a signal conditioning and acquisition circuit principle diagram, and their working principles are described in this paper.In the design of software of testing system, develop advantages and characteristics of virtual instrument software program, using the modular design method, improves the running performance and function test system software program on the scalability. The system can real-time monitor the parameters of the diesel engine ,temperature, pressure, speed, vibration parameters, the parameters of limit to alarm, and can simultaneously store operation data under various conditions, convenient for later processing.The virtual instrument test system can map the diesel engine indicator diagram. Design the signal shaping circuit and signal frequency circuit on the upper dead point signal and the crankshaft rotation signal, the cylinder pressure signal sample according to the crankshaft angle. The indicator diagram were processed and analyzed, compared with different noise reduction processing method for indicator diagram, and according to the diesel engine indicator diagram, the method is given for calculating the thermodynamic performance parameters of diesel engine, compared with foreign similar test system, it can meet the precision requirement. Experiments show that the application of virtual instrument technology to the diesel engine test is feasible, convenient and effective.