Development Of Portable Cylinder Pressure Acquisition System On Marine Diesel Engine

The diesel engine parameter acquisition system can monitor the running status of the diesel engine in real time.By collecting parameters such as cylinder pressure,information about the combustion and heat release process of the diesel engine can be obtained,so as to realize the fault diagnosis of the diesel engine,which is of great significance to ensure the stable operation of the diesel engine.Among them,the surveying and mapping indicator diagram is the main way to evaluate the working status of the diesel engine cylinder.In this paper,a four-stroke diesel engine is used as a test prototype,and hardware circuits such as signal conditioning,data storage,and serial communication are built.A portable marine diesel cylinder pressure acquisition system based on a single-chip microcomputer system is designed,and the upper computer data processing and analysis software is designed through the Lab VIEW platform..The system can be separated from the upper computer and use the single-chip microcomputer to realize the functions of data collection,storage and display.It can also transmit the data to the upper computer to realize two kinds of indicator diagram conversion,further filter processing of the indicator diagram,heat release rate calculation and other functions.In order to realize data processing and image noise reduction,the MCU is used to process the data in offline mode,including removing,replacing singular points,averaging and filtering noise reduction.The noise reduction effects of arithmetic average filtering,limiting filtering and median filtering are compared,and the results show that the arithmetic average filtering has a better inhibitory effect on the channel effect of the indicator diagram and other power frequency interference,and can achieve the effect of noise reduction.In the online mode,the upper computer data processing and analysis software performs further smoothing processing on the data,comparing the smoothing effect of the five-point three-fold smoothing method,LMS adaptive filtering,etc.,and finally shows the latter method The smoothing effect of the work map is more ideal.The system is convenient and flexible to operate,and the working mode can be switched autonomously by pressing the buttons,which can realize offline collection,improve portability,and realize online work to improve data processing and display accuracy.Simulation experiments and bench tests have verified the feasibility of the marine diesel cylinder pressure acquisition system.At the same time,it is very convenient in operation,which can fully meet the needs of the collection of cylinder pressure and other information,as well as the corresponding analysis.