本研究針對新型雙搖臂式氣門機構的推頂面曲線與凸輪輪廓作設計及動態分析,先制定推頂面曲線及凸輪輪廓產生法則,並以MATLAB撰寫相關程式,所得之曲線數據轉匯入到Solidworks電腦輔助設計軟體加以繪製,接著利用機構分析軟體ADAMS,作動態模擬分析。此新型機構是將傳統氣門機構之單搖臂,改良成兩組搖臂,第一組搖臂具有固定搖臂、可調整搖臂與可變控制軸,其中固定搖臂與凸輪相接,可變控制軸控制著固定搖臂與調整搖臂的夾角。調整搖臂會以滾輪與第二搖臂之推頂面靠接,並藉以推動第二搖臂,第二搖臂則與氣門閥相接,藉以產生相對應之升程變化。藉由改變固定搖臂與調整搖臂的角度,可以達到連續可變氣門升程與正時。設計的重點乃依據現有氣門升程曲線為基底,並基於提出之產生法則,計算出推頂面曲線及凸輪輪廓,接著比較和檢視各主要設計參數對機構特性之影響,找出適當的曲線並據以建模。接著再進行機構模擬分析並與傳統氣門機構作比較,結果可作為發展出實體機構之重要參考。
This study aims at computer-aided design and dynamic simulation analysis on a push camber and cam for the new double-rocker variable timing and lift valve mechanism. MATLAB software will be used to compute the curve of Push Camber and Cam that are imported into the computer-aided design software Solidworks to create solid models. Then using the simulation software ADAMS is used to do dynamic simulation analysis. The new mechanism is intended to modify the conventional single rocker arm into a set of two rocker arms, called the first and second rocker arms respectively. The first rocker arm consists of a fixed rocker arm, adjustable rocker arm and variable control shaft. The fixed rocker arm is connected against the cam, and the variable control shaft control the angel between the fixed rocker arm and adjustable rocker. The adjustable rocker pushes the second rocker arm. The second rocker arm serves to lift the valve. The axial movement of the control shaft is varied to achieve variable lift. The design is focused on computing the camber and cam. By comparing the results, the most appropriate curve cam be found and used to perform simulation and comparison with the conventional mechanism. The results can serve as an important reference for future development and realization of the proposed new mechanism.