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A Study On Diagnosing The Power Distribution Of Each Cylinder According To Angular Vibration

Posted on:2003-02-23Degree:DoctorType:Dissertation
Country:ChinaCandidate:D W DongFull Text:PDF
GTID:1102360065464293Subject:Vehicle Engineering
Abstract/Summary:PDF Full Text Request
Along with the development of our country transportation and the demand for advanced maintain systems,to explore an advanced,simple and effective technology for the condition monitoring and fault diagnosis of I. C. engine has become the tasks extensively attended by many domestic and foreign experts. Because a lot of information about the power condition of I.C. engine is contained in the angular vibrating curves of crankshaft,many scholars do research on the fault cylinder diagnosis by use of the transient speed curves of I.C. engine,and some progresses are acquired,but there are some problems such as the poor diagnosis accuracy in some cases and the limited application range. Based on the theory analysis,computer simulations and experiment researches,the problem according to any angular vibration curve of crankshaft to diagnose the power of each cylinder of I. C. engine,are completely solved and the concerned equipment is developed in this paper.The effect of uneven power and compression condition of each cylinder of diesel engine on the crankshaft instantaneous rotation (velocity and acceleration) curves and their interrelationship in different cylinder numbers and rotation speeds have been thoroughly analyzed by means of the crankshaft instantaneous rotation curves simulated by computer. Several characteristic parameters are extracted from the angular velocity curve and the acceleration curve of crankshaft instantaneous rotation,and the quality of them is evaluated by use of the gray relation analysis method and the method for inspecting the consistency of the extremum cylinder number. It is discovered that the fluctuating increment of the instantaneous angular acceleration curve of crankshaft ( Ay method) put forward in this paper can be used to diagnose the power and compression condition of multi-cylinder engine in the state of shorter,more rigid crankshaft and lighter torsional vibration and in the rapidly diagnosed situation,and the Ay method is better than the fluctuating increment of the instantaneous rotation speed curve of crankshaft (n method) which is used widely now.To adapt the circumstance in which the crankshaft torsional vibration generallyexists,the new method (TVRS method) in which the cylinder power is inversely solved according to the torsional vibration curve is put forward and deduced in this paper,that is,the average effective pressure of each cylinder i.e. power condition of each cylinder is estimated based on a crankshaft torsional vibration curve according to the elasticity model of the actual shafting of engine and by use of the I. C. engine dynamics,the numerical calculations and the signal theory etc. Although the computing workload is more,the method makes full use of the now available data of the torsional vibration of the I. C. engine,and can be used to all kinds of I. C. engine on any kind of operating condition,so it has higher application value.In order not only in theoretics but also in practice to completely resolve the power diagnosis of each cylinder of I.C. engine according to the angular vibration curve of crankshaft,the PC instruments - crankshaft angular vibration measurement and analysis system (TVM system) and the electrical calibrator (TVCI system),in which the soft and hardware resources of computer are sufficiently utilized,are developed by author. The application on 6 large enterprises indicates that TVM system is an instrument with advanced technology,reasonable design,convenient operation,perfect function and high accuracy.The measure errors of the instantaneous rotation speed,which is measured by non-contact and magnetoelectricity sensor,have been completely investigated in this paper also. To eliminate the errors,the parallel double-sensor scheme which can eliminate the influence of the tooth space error of the measurement tooth-wheel and the contraposition double-sensor scheme which can reduce the influence of the installing eccentric error of the measurement tooth-wheel are demonstrated in detail and realized in this paper. The test-bed...
Keywords/Search Tags:I.C.engine, fault diagnosis, PC instrument, angular vibration
PDF Full Text Request
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