【正文】 .................................... 12 鏈輪的設(shè)計(jì) ........................................... 14 挺柱的設(shè)計(jì) ........................................... 14 氣缸蓋的設(shè)計(jì) ......................................... 15 四、結(jié) 論 .......................................................... 16 參考文獻(xiàn) ........................................................... 17 致謝 ............................................................... 18 重慶科技學(xué)院本科生畢業(yè)設(shè)計(jì) 1 緒論 1 1 緒論 近幾十年來，摩托車作為人們從事各項(xiàng)社會(huì)活動(dòng)的重 要交通工具，已經(jīng)越來越廣泛的被人們所使用。 關(guān)鍵詞： 發(fā)動(dòng)機(jī) VVT 機(jī)構(gòu) 低能耗 低污染 動(dòng)力性 重慶科技學(xué)院本科生畢業(yè)設(shè)計(jì) ABSTRACT II ABSTRACT With the development of science and technology and economy, human based on the requirement of environment protection and sustainable development of human, low energy consumption, low pollution and power performance has bee the development direction of gasoline engine. Variable distribution phase technology has bee one of new technology development direction. Based on the prehensive discussion and understanding of engine variable distribution phase technology development at home and abroad, based on the introduced variable with gas phase (VVT) technology in the application of four stroke motorcycle engine of four valves and the advantages of using. Due to the development of the motorcycle in our country and our country the influence of many factors such as roads, motorcycle engine operating under many conditions transform is more, the study of motorcycle engine, the basic principle of variable distribution phase control mode and the working principle of the actuator to discuss using the variable distribution phase technology before and after impact on engine performance are very necessary. At the same time for double overhead camshaft (DOHC) motorcycle engine designs an applicable variable with gas phase mechanism, which is mainly posed of double inlet valve, double inlet CAM, double inlet lifter and timing of switching mechanism, can make double inlet CAM and double inlet lifter according to different operating conditions by the timing to switch switching mechanism. The design of variable distribution phase (VVT) mechanism, in the low speed under low load condition, the CAM contour line speed work, can shorten the valve open time, can reduce the valve lift, can decrease into the fresh air in the cylinder, may achieve the purpose of reducing engine fuel consumption, can increase the torque. Under high load conditions, the use of CAM contour line high speed work, can prolong the valve open time, can increase the valve lift, make more fresh air into the cylinder, can achieve the purpose of increase engine power output. Its main design content includes the valve group (valve, valve guide, valve seat and valve springs and other parts) in the design and valve train group (camshaft, sprocket, lifter, etc.) design. Keywords: engine。同時(shí)針對雙頂置凸輪軸型（ DOHC）摩托車發(fā)動(dòng)機(jī)設(shè)計(jì)了一種適用的 可變配氣相位 機(jī)構(gòu) ，該機(jī)構(gòu)主要由雙進(jìn)氣氣門、雙進(jìn)氣凸輪、雙進(jìn)氣挺柱及正時(shí)切換機(jī)構(gòu)組成，可以使雙進(jìn)氣凸輪和雙進(jìn)氣挺柱根據(jù)不同運(yùn)行工況由正時(shí)切換機(jī)構(gòu)進(jìn)行切換。 畢業(yè)設(shè)計(jì)（論文）作者（簽字）： 年 月 日 重慶科技學(xué)院本科生畢業(yè)設(shè)計(jì) 摘要 I 摘 要 隨著科學(xué)技術(shù)和經(jīng)濟(jì)的發(fā)展，人類基于環(huán)境保護(hù)和人類可持續(xù)發(fā)展的要求，低能耗、低污染和動(dòng)力性已成為 汽油發(fā)動(dòng)機(jī)的發(fā)展方向。 ：任務(wù)書、開題報(bào)告、外文譯文、譯文原文（復(fù)印件） 。 、圖表要求： 1） 文字通順，語言流暢，書寫字跡工整，打印字體及大小符合要求，無錯(cuò)別字，不準(zhǔn)請他人代寫 2） 工程設(shè)計(jì)類題目的圖紙，要求部分用尺規(guī)繪制，部分用計(jì)算機(jī)繪制，所有圖紙應(yīng)符合國家技術(shù)標(biāo)準(zhǔn)規(guī)范?？勺兣錃庀辔患夹g(shù)已成為新技術(shù)發(fā)展方向之一。 本次設(shè)計(jì)的 可變配氣相位 (VVT)機(jī)構(gòu)，在低速低負(fù)荷工況下，采用低速凸輪型線工作，可縮短氣門開啟時(shí)間，可減小氣門升程，可減少進(jìn)入氣缸中的新鮮空氣，可能達(dá)到降低發(fā)動(dòng)機(jī)燃油消耗的目的，可增大了扭矩。 VVT mechanism 。隨著國民經(jīng)濟(jì)快速發(fā)展和人們生活水平的不斷提高，人們的出行頻率增多，活動(dòng)范圍不斷擴(kuò)大，對交通工具的快速性、機(jī)動(dòng)性和可靠性越來越高 [1]。目前，這些新技術(shù)和新方法，有的已在內(nèi)燃機(jī)上得到 應(yīng)用，有些正處于發(fā)展和完善階段，有可能成為未來內(nèi)燃機(jī)技術(shù)的發(fā)展方向 [2]。而可變配氣相位 (VVT)技術(shù)已成為新技術(shù)發(fā)展方向之一 [3]。普通發(fā)動(dòng)機(jī)的進(jìn)、排氣門的開、閉都由進(jìn)、排凸輪進(jìn)行驅(qū)動(dòng)，因?yàn)檫M(jìn)、排凸輪型線是固定不變的所以進(jìn)、排氣門的早開角、晚關(guān)角也固定不變，這就意味著只能在某一轉(zhuǎn)速下發(fā)動(dòng)機(jī)才處于最佳的配氣相位狀態(tài)，而在發(fā)動(dòng)機(jī)轉(zhuǎn)速很低或很高時(shí)，就會(huì)出現(xiàn)配氣相位處于不理想的狀態(tài)。使得發(fā)動(dòng)機(jī)的動(dòng)力性、經(jīng)濟(jì)性及排氣污染等都得到了一定的改善。對摩托車發(fā)動(dòng)機(jī)進(jìn)行全面的技術(shù)改造和提升成為一個(gè)緊迫的問題。 我國摩托車工業(yè)發(fā)展是快速和迅猛的。從排量上看，中國 135 家生產(chǎn)企業(yè)開發(fā)的 2417 種新產(chǎn)品主要是 250mL、 150mL、 125mL、 110mL、100mL 和 50mL 等中、小排量摩托車。通過跟蹤國內(nèi)外車用發(fā)動(dòng)機(jī)可變配氣正時(shí)的發(fā)展水平和技術(shù)現(xiàn)狀 , 借鑒現(xiàn)有的 VVT 機(jī)構(gòu)，并在此基礎(chǔ)上進(jìn)行優(yōu)化設(shè)計(jì)，制定出合理的設(shè)計(jì)方案 ,從而解決高轉(zhuǎn)速與低轉(zhuǎn)速、大負(fù)荷與小負(fù)荷發(fā)動(dòng)機(jī)動(dòng)力性與經(jīng)濟(jì)性的矛盾。例如：①重慶科技學(xué)院本科生畢業(yè)設(shè)計(jì) 1 緒論 3 Benz 公司的 500SL 型車用 V8 發(fā)動(dòng)機(jī)采用了可變氣門正時(shí)機(jī)構(gòu)，使用進(jìn)氣凸輪軸兩點(diǎn)調(diào)相法來改變氣門正時(shí)。本田最近新出臺(tái)的三段式 VTEC 發(fā)動(dòng)機(jī)，能在低、中、高三種不同狀態(tài)下讓氣門