Investigation On Dynamic Exciting Force Identification Of Motorcycle Engine

As requirement of people in rider's comfort of motorcycle is heightened, vibration and noise of motorcycle engine have become focus, vibration and noise decrease of engine have become important topic in correlative field. It is necessary to identify dynamic exciting force of motorcycle engine in operation, in order to avoid blindness in vibration decrease and noise reduction engineering of motorcycle. Based on identification of rigid body inertia parameters, test engineering investigation on dynamic exciting force identification of engine is carried out. It is possible to determine vibration source and load transfer path of engine, and theoretical basis to optimize load transfer path is put forward.Firstly, theory basis to identify rigid body inertia parameters using massline of frequency response function is expatiated on, mechanism of engine exciting force is analyzed, and three methods of exciting force identification of engine are introduced. Secondly, The engine of motorcycle is considered as investigation object,error analysis of rigid-body inertia parameter identification is carried out, based on rigid-body inertia parameters identification using massline theory. It is pointed out that the choices of response and excitation points are the key factors of identification's precision. By means of matrix analysis, some methods of improving identification's precision are proposed. The results are validated by engineering example. The groundwork of accurate rigid-body inertia parameters identification is built up. The test of measuring frequency response function is carried through, based on massline theory of acceleration frequency response function, software package to identify rigid body inertia parameter is gotten by MATLAB.The test bench of engine's exciting force is built, test bench of engine exciting force is installed exactly on base of test bench of engine, dynamic force of four measuring points is tested respectively in ignition condition and load condition. The exciting force of bench connecting rigidly with engine is measured, to obtain the exciting force of engine. Dynamic force of four measuring points is transformed into force at gravity center of engine, exciting force of engine is obtained.Identification of motorcycle engine's dynamic force can aided to settle basis for suspension design of engine(suspension arrangement and suspension rigidity), engine design and fault diagnosis, and groundwork of big displacement engine's design and application is built up.