The Synthetical Balance Study Of Motorcycle Engine Based On Mechanical System Dynamics

The motorcycle industry has developed for more than 20 years in China. Since 2002, our country has become the biggest producer of motorcycles in the world. However, our country is not a powerful motorcycle producer. Compared with motorcycles made in the world-known enterprise, our motorcycle isn't satisfying in comfort and performance. Especially motorcycle vibration hasn't been well solved in motorcycle design and manufacture.It is valid to adopt balanced shaft to solve the motorcycle vibration currently, but the balanced shaft will greatly increase the manufacturing cost. The vibration of motorcycle often occurs in the single-cylinder engine without balancer shaft, which has the biggest market share. So, it is valuable to probe into the vibration of the engine without balanced shaft to direct the engine design and transform the existing production.The article, based on the theory of mechanical system dynamics, begins with the through vibration source—motor engine, combining the combustion process of motorcycle engine. And the study of synthetical balance of motorcycle engine is carried out. The method to solve the motorcycle vibration is put forward for the first time. At last the engineering application proves effective in solving the vibration problem. The study mainly includes the following work.①Aim to solve the motorcycle vibration problem in engineering fulfillment, and find out the reason for causing vibration. According to the data the factory provides, the dynamometer card analysis is carried out on the motorcycle engine, to discover the abnormal variation of cylinder gas pressure, and the abnormal combustion of motorcycle engine, so the motorcycle has the abnormal combustion vibration.②Do the thorough research on the abnormal combustion vibration, and built up a set of analysis method and means of it.1)Based on the theory of mechanical system dynamics, the study analyzes the motion variation of engine under the abnormal combustion. The fluctuation of cylinder gas pressure under the abnormal combustion makes the motion of crankshaft connecting rod system change. The article, based on the theory of mechanical system dynamics and the combustion force as input excitations, analyzes the motion variation of the engine under the abnormal combustion.2)Based on the real motion law of engine, the research is done on the equilibrium characteristics in the case of abnormal combustion. As the engine combusts abnormally, because of the change of the motion law of crankshaft connecting rod system, the inertia force changes correspondingly. This research, based on the real motion law of engine, is done on the inertia force of engine to educe the curve of equilibrium characteristics of the motorcycle engine under the abnormal combustion.3)Do research on the variations of overturning moment of motorcycle engine in the case of abnormal combustion. As the engine combusts abnormally, the abnormal change of cylinder gas pressure causes the obvious change of overturning moment of motorcycle. This article analyzes the overturning moment of the abnormal combustion, and educes the changing law of the overturning moment under the abnormal combustion.③The analysis of abnormal combustion on the engine vibration is done to compare equilibrium characteristics and the overturning moment under normal and abnormal combustion. The result shows the abnormal combustion has an influence on engine vibration.④Based on the hereinbefore research, this article, aiming at the influence on motorcycle engine vibration under the abnormal combustion, puts forward the synthetical balance method to solve the vibration problem for the first time. That is, make the motorcycle engine combust normally by adjusting the ignition advance angle and compression ratio, and combine frame characteristic making balance to the crankshaft connecting rod system. Thus the problem of motorcycle engine vibration can be well solved.⑤Based on the above research, the analysis software is explored in this article, that is, the Synthetical Balance Study of Motorcycle Engine Based on Mechanical System Dynamics.⑥Put the theory and method in the article to solve the YG150 motorcycle vibration. By adjusting the ignition advance angle and compression ratio, and combine good frame characteristic. The application proves effective in solving the problem.