Experimental Research And System Development Of Ice Working State Monitoring And Fault Diagnosis

As a widely used power source,the monitoring of its operating conditions is an important aspect to improving the economical efficiency of internal combustion engine.The traditional internal combustion engine fault diagnosis method is time-consuming and inefficient,it is difficult to diagnose complex internal combustion engines,so the condition monitoring and fault diagnosis techniques must be optimized and developed.The crankshaft of the engine is subjected to a complex alternating excitation torque and transmits the torque,which directly reflects the operation of the engine,and contains the information of the running engine,therefore,the crankshaft angular vibration signal is valuable for practical diagnosis.In order to solve the problem of applying the theory of condition monitoring and fault diagnosis based on crankshaft vibration to engineering application,a fast aberration filtering algorithm based on five-spot triple smoothing filter is proposed in this paper;The influence of monitoring threshold of engine operating condition on monitoring results is studied;A new method of calculating the output power of engine is put forward;Based on all the above,developed the Working States Monitoring and Fault Diagnosis system of internal combustion engine(Working States Monitoring and Fault Diagnosis—WSMFD).In order to eliminate the error caused by the distortion of the speed signal in the torsional vibration measurement of the internal combustion engine,a fast distorted point filtering method is proposed on the basis of the existing anomaly filtering method.According to the characteristic of five-spot triple smoothing filtering,determining the position of distorted point,the data near the distorted points are smoothed and the amplitude is replaced.This algorithm greatly reduced the computational complexity,improved the efficiency of filtering processing.Experiment and forced vibration simulation of a natural gas internal combustion engine are conducted to analysis the distribution of angular vibration characteristic harmonic amplitude of normal and abnormal condition,It is proved that the theory of state monitoring of internal combustion engine based on crankshaft angular vibration is also applicable to the natural gas engine,and the selection of threshold value of shafting is instructed,which can be used as reference for the design of state monitoring system of the same type.There are significant differences in the distribution range of the 0.5th harmonic amplitude at different rotational speeds,and the appropriate state monitoring threshold is selected according to the different speed.According to the experimental results of natural gas internal combustion engine,the curve of the third harmonic amplitude of crankshaft angular vibration is "V" type,which shows that the influence of reciprocating inertia moment can not be ignored.Taking the effect of reciprocating inertia force on the 3ed harmonic amplitude of the crankshaft angular vibration displacement into consideration,the relationship between the crankshaft angle vibration and the internal combustion engine power is consummated.The effects of the gas excitation force and the reciprocating inertia force of the diesel engine and the natural gas internal combustion engine on the angular amplitude of the angular vibration characteristics at the crankshaft are compared.Curves of the 1.5th,3ed,6th harmonic amplitude varies with powers were studied,which directed the selection of the calculation of characteristic harmonic amplitude of the output power of the internal combustion engine based on the crankshaft angular vibration response.The results of simulation and experimental verify the feasibility of the output power of the internal combustion engine by using the harmonic amplitude of crankshaft torsional vibration angle.The maximum deviation applied to the diesel engine is 3.2%,and the maximum deviation is 3.5%on the natural gas engine.Based on the above research,WSMFD software is developed to improve the efficiency of monitoring of working condition and the fault diagnosis system of internal combustion engine.The software includes a signal processing program based on the fast distortion filter method,which can filter out the abnormalities of the signal,monitoring the running state of the internal combustion engine,diagnosing the fault cylinder number and calculating the output power.The software platform is designed for internal combustion engine working condition monitoring and fault diagnosis,and the software has strong pertinence and compatibility,and can interact with the existing software;The software interface is simple and easy to use;the calculation speed of the program is fast,and it occupies less computer resources,and it's easy for users to achieve the state of internal combustion engine monitoring and fault diagnosis,so it has high engineering application value.In summary,this paper has improved the working condition monitoring and fault diagnosis method of internal combustion engine based on crankshaft angle vibration,and has carried on a lot of simulation research and experimental verification.Developed the WSMFD system,enriched the technology of monitoring and fault diagnosis.