本文使用實體元素建構模型，以模擬的方式比較市面上的現行車種超5與G5在駐車怠速時震動上的差異，兩者主要的改變在於超5為水平式吊架，而G5為非水平式吊架，水平式吊架的意思為吊架鎖車架與鎖引擎的鎖點間連線與引擎活塞運動方向平行。
　　針對駐車怠速下的情況作探討時，引擎平均轉速設定為1800rpm，而在缺少引擎爆炸壓力圖的狀況下，只能以引擎的實體模型進行定轉速的分析，得到在定轉速下的搖撼力，因此搖撼力在傅立葉分析後，最低頻率項為30Hz。而以此搖撼力作頻譜分析後，超5的振動是大於G5的震動。但由於實際引擎並非定轉數的狀態，故將搖撼力作傅立葉分析時最低頻率會出現15Hz的分量，搖撼力矩部分也會分析出15Hz的分量，接著在搖撼力及搖撼力矩的頻譜響應圖中，可以觀察到15Hz的振幅是遠大於30Hz的振幅，因此15Hz影響振動的比例會比30Hz大很多。而在頻譜響應圖中，15Hz的部分，無論是搖撼力矩或是搖撼力，都明顯看出超5是優於G5的。
　　搖撼力矩部分，經由單位力矩的簡諧分析，發現超5水平式吊架在所有頻率項的振幅平均值，僅為G5非水平吊架的61%，因此可以得知水平式吊架在搖撼力矩的影響下，比非水平式吊架更可以減少引擎傳至車架上的振動。
　　應用簡諧分析去討論有無止動橡膠在駐車怠速下對振動的影響，可以得到兩個結果。第一個為不同方向的力，對於同一個共振頻率影響程度是不同的，若力的方向與共振模態的運動方向相同，會引起非常大的振動，第二個為直交原理的設計方法是需要考慮共振頻率與共振模態的，因為在部分的共振模態下，垂直吊架的力引起的振動反而會大於平行吊架的力。

　　In this paper, we simulated two scooters, G5 and MEGA 5,by solid element to compare vibration conditions at idle speed of the two scooters. The main difference between these two scooters is the arrangement direction of engine hanger: the hanger of MEGA 5 is in horizontal direction while the hanger of G5 is not. Here, the horizontal direction hanger means that the direction of the line connected by two joints, the joint between frame and hanger and the joint between hanger and engine, is parallel to the line of the motion of piston.
　　Generally, the idle speed of scooter engine is 1800 rpm. Without an actual data of cylinder pressure of the engine, we assumed a constant angular velocity condition of the crankshaft to derive the shaking force of engine. Because of this assumption, the fundamental frequency of shaking force which is computed by Fourier Transform is 30Hz. And we found that the vibration of MEGA 5 subjected to a constant-angular-velocity-condition shaking force is larger than G5 in the same condition. But in a real case, which is not in constant angular velocity condition, the frequency of shaking force computed by Fourier Transform will have a component of 15Hz,and so as the frequency of shaking moment. According to frequency response diagrams, the amplitude of 15Hz is much larger than the amplitude of 30Hz. Thus we say that 15Hz play a more important role than 30Hz during vibration.
　　The results of harmonic response analysis of the two scooters subjected to unit load shaking moment indicated that the amplitudes related to any frequencies of MEGA 5,with horizontal engine hanger, are only 61% of the amplitudes of G5.
　　Discussing the vibration effected by stop-rubber at idle speed with harmonic analysis, we observed two results. First, the result of vibration of a frequency subjected to forces in different directions will be different. If the direction of harmonic force is the same with the direction of the modal motion, the response amplitude will be very large. Second, while applying orthogonality theory, the concepts of resonance frequencies and modes should be included. With some vibration modes, the response caused by the force perpendicular to engine hanger may be greater than by the force which is parallel to engine hanger.

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