Study On Parameter Identification System Of I.C. Engine Based On Genetic Algorithm

As I. C. engine is in operation, the crankshaft produces forced torsional vibration because of tangential force and normal force which value and direction change periodically. The crankshaft system installed with component which has enormous moment of inertia that leads to lower frequence of forced torsional vibration for crankshaft. Usually syntony happens within operating rev that has great effect on the reliability and stability of the I.C. engine.Theoretical Calculation of shafting has achieved quite development for decades and a complete theory has been set up about calculating free vibration and forced vibration of shafting. Although calculation of torsional vibration is almost ideal, many external factors affect the calculating result. Calculating equation of torsional vibration base on the parameters of inertia, stiffness and damp. The difference exists between theoretical result and actual result is leaded by error of the parameters, which can not get the expecting purpose.In addition, with the development of calculating torsional vibration and measuring technique, the parameter of calculating torsional vibration has been applied in the diagnosis of the condition for power of I. C. engine such as TVRS method . Since TVRS method is a diagnosis method based on the modern theoretical calculation of torsional vibration and measurement, it needs take full advantage of data about shafting inertia, stiffness and damp. The error of all kinds of structural parameters has the decisive influence on the diagnosis precision.Combining genetic algorithm with calculating method for torsional vibration to identify the structural parameter of shafting is the first put forward in the system. It has such benefits that it can overcome the disadvantage of manual adjusting structural parameter by experts and multi-parameter identifying at the same time. The paper on the basis of TVCA develops a parameter identification system of shafting based on the genetic algorithm and tries to identify the parameter of shafting of I.C. engine. The primary fruit has been achieved.Preliminary research has undergoing according to the conception of shafting sensitivity. Also the rule of granting error for the inertial and stiffness has been presented. Judging rules adopted in the research of simulation are put forward.