有鑑於凸輪機構一向廣泛地運用於引擎的閥門控制,在國內尋求自行製造汽車引擎的同時,如果能發展出確實可靠的技術以檢測閥桿的動態,則將有利於提昇引擎的品質。因此,本研究的目標即在於發展凸輪傳動機構的數位檢測技術,並運用來檢測引擎的閥門機構。為了達成研究的目標,我們製作一個具有直壓式從動件的凸輪機構。同時建立感測系統以進行機構測試。在感測器的配置上,我們使用旋轉編碼器來檢測凸輪軸的旋轉,並以光學尺來檢測從動件的線性位移。在訊號擷取方面,我們選用研華公司的PCL833介面卡執行數位解碼。同時製作一個計時/計速介面卡以計量機構的瞬間速度。因此我們不僅可以量測從動件的位移曲線與瞬間速度,甚至可以精確地計算出閥門開啓的時間。研究過程中,我們分別以低、中、高三種轉速平動凸輪機構。從實驗結果發現,從動件在升程與降程中極易產生振動,尤其當凸輪軸在高速運轉時,從動件的跳動更將影響到閥門的開啓與關閉。因此,本量測技術可以協助設計者瞭解其引擎閥門機構的動態是否達到頂期的性能。
The purpose of this project is to apply the digital sensoring and signal processing technique to develop an automatic inspection technique for a cam mechanism. As cam mechanism has been widely used in the valve system of engine, how to measure the performance of the valve system has interested the manufacturers. Thus, this project is to develop a useful method that is able to measure the motion of the valve. In the development of this project, we used digital sensoring instruments to detect the (angular) displacement and the (angular) velocity of the cam mechanism. Since the digital technique is noise-free, and is faster than the analog methods, we are able to measure the high speed cam mechanism. During the past year, we built a cam mechanism that is similar to the valve system of the car engine. We also installed a high speed data acquisition system to measure the motion of the cam mechanism. Based on the technique developed in this project, we are able to detect the opening period of the valve. We found that when the speed of the cam shaft is increased, the opening period of the valve becomes longer than the normal design, which may influence the performance of the engine.