[學習]發(fā)動機結構及工作原理介紹

1、1,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial prop

2、erty rights.,,,,發(fā)動機結構及工作原理介紹,,,,,http://www.docin.com/sundae_meng,2,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distrib

3、ution, as well as in the event of applications for industrial property rights.,,,,1892 INVENTION-DIESEL,3,柴油機,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, ex

4、ploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,,4,發(fā)動機分類,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also reg

5、arding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,分類方式：點火方式、沖程數、缸數及排列、冷卻。,點燃式發(fā)動機 壓燃式發(fā)動機,點火方式,●汽油自燃溫度

6、高，采用火花塞強制點火，汽油發(fā)動機為點燃式發(fā)動機?！癫裼妥匀粶囟鹊停捎酶邏嚎s比壓燃，柴油發(fā)動機為壓燃式發(fā)動機。,5,發(fā)動機分類,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribut

7、ion, as well as in the event of applications for industrial property rights.,,,,沖程數,二沖程發(fā)動機,四沖程發(fā)動機,曲軸旋轉一周完成一個工作循環(huán)。由于換氣不徹底，經濟性較差，但結構簡單，因此在摩托車上廣泛使用。,曲軸旋轉二周完成一個工作循環(huán)。四沖程發(fā)動機有獨立的進氣和排氣沖程，換氣徹底，在汽車上廣泛使用，并已逐漸用于摩托車。,6,發(fā)動機分類,Depart

8、ment | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rig

9、hts.,,,,缸數及排列,L 4 2.4L,V 6 3.0L,,,,V形排列,6缸,排氣量,,,,直列發(fā)動機,V形發(fā)動機,水平對置發(fā)動機,7,發(fā)動機分類,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, edit

10、ing, distribution, as well as in the event of applications for industrial property rights.,,,,進氣狀態(tài),按進氣狀態(tài)不同，活塞式內燃機還可分為增壓和非增壓兩類。若進氣是在接近大氣狀態(tài)下進行的，則為非增壓內燃機或自然吸氣式內燃機；若利用增壓器將進氣壓力增高，進氣密度增大，則為增壓內燃機。增壓可以提高內燃機功率。,8,Department | 1

11、1/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,工

12、作方式,轉子式發(fā)動機,活塞式發(fā)動機,發(fā)動機分類,●轉子發(fā)動機又稱為米勒循環(huán)發(fā)動機。它采用三角轉子旋轉運動來控制壓縮和排放， 與傳統(tǒng)的活塞往復式發(fā)動機的直線運動迥然不同 ?！褶D子發(fā)動機取消了無用的直線運動，因而同樣功率的轉子發(fā)動機尺寸較小，重量較 輕，而且振動和噪聲較低，具有較大優(yōu)勢?！袢寝D子把汽缸分成三個獨立空間，三個空間各自先后完成進氣、壓縮、做功和排 氣，三角轉子自轉一周，發(fā)動機點火做功三次。●還存在氣密性、

13、潤滑和磨損等一系列技術難題。,9,工作原理,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications

14、 for industrial property rights.,,,,,二沖程汽油機工作原理,二沖程柴油機工作原理,10,發(fā)動機工作原理,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distr

15、ibution, as well as in the event of applications for industrial property rights.,,,,氣缸內油氣混合氣燃燒產生壓力，推動活塞往復運動，通過曲柄連桿機構轉化為曲軸的旋轉運動進行動力輸出。,☆ 發(fā)動機工作循環(huán),11,發(fā)動機示功圖,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All righ

16、ts reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,12,發(fā)動機常用術語,Department | 11/05/2010 | © Robert

17、Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,①上止點②下至點③活塞行程④燃燒室容積

18、⑤工作容積⑥總容積⑦壓縮比ε=,13,發(fā)動機性能指標,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of a

19、pplications for industrial property rights.,,,,,發(fā)動機的性能指標用來表征發(fā)動機的性能特點，并作為評價各類發(fā)動機性能優(yōu)劣的依據。同時，發(fā)動機性能指標的建立還促進了發(fā)動機結構的不斷改進和創(chuàng)新。,一、動力性指標,1.有效轉矩,記作 Te，單位為 N·m,2.有效功率,3.發(fā)動機轉速,用 n 表示，單位為 r/min,4.平均有效壓力,單位氣缸工作容積發(fā)出的有效功稱為平均有效壓力，記作

20、Pme，單位為 MPa,14,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for in

21、dustrial property rights.,,,,,二、 經濟性指標,1.有效熱效率,燃料燃燒所產生的熱量轉化為有效功的百分數稱為有效熱效率，記作 ηe。顯然，為獲得一定數量的有效功所消耗的熱量越少，有效熱效率越高，發(fā)動機的經濟性越好。,2.有效燃油消耗率,發(fā)動機每輸出 1kW 的有效功所消耗的燃油量稱為有效燃油消耗率，記作 be，單位為 g/（kW·h）。,式中：B—發(fā)動機在單位時間內的耗油量，kg/h；　　　P

22、e—發(fā)動機的有效功率，kW。,15,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for

23、 industrial property rights.,,,,,三、強化指標,強化指標是指發(fā)動機承受熱負荷和機械負荷能力的評價指標，一般包括升功率和強化系數等。,1.升功率,發(fā)動機在標定工況下，單位發(fā)動機排量輸出的有效功率稱為升功率。升功率大，表明每升氣缸工作容積發(fā)出的有效功率大，發(fā)動機的熱負荷和機械負荷都高。,2.強化系數,平均有效壓力與活塞平均速度的乘積稱為強化系數。活塞平均速度是指發(fā)動機在標定轉速下工作時，活塞往復運動速度的平均

24、值。,四、緊湊性指標,1.比容積,發(fā)動機外廓體積與其標定功率的比值稱為比容積。,2.比質量,發(fā)動機的干質量與其標定功率的比值稱為比質量。干質量是指未加注燃油、機油和冷卻液的發(fā)動機質量。,16,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, re

25、production, editing, distribution, as well as in the event of applications for industrial property rights.,,,,,八、工藝性指標,17,發(fā)動機本體概述,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regard

26、ing any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,發(fā)動機本體概述: ★ 發(fā)動機本體主要包含缸蓋、缸體等零部件 ★ 發(fā)動機本體既是發(fā)動機各機構、各系統(tǒng)的裝配基體又同時是發(fā)動機其它機構/系統(tǒng)的

27、組成部分,缸體,缸蓋,18,缸體概述,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications fo

28、r industrial property rights.,,,,缸體作用: ★ 是發(fā)動機的骨架以及相關零部件的安裝基體 ★ 發(fā)動機燃燒室/冷卻水道/潤滑油道的組成部 ★ 承受發(fā)動機工作時可燃混合氣產生的氣體力以及發(fā)動機運動件的慣性力 ★ 承受周期性的熱沖擊,典型缸體結構圖,19,缸體分類,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All

29、rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,缸體按照曲軸孔對開的位置是否與缸體下表面(OP面)同一平面可常分為以下三種:一般式: 曲軸孔

30、對開位置與缸體下表面同一平面 龍門式: 曲軸孔對開位置高于缸體下表面 隧道式：曲軸孔沒有對開，適用于安裝滾動軸承的組合式曲軸的缸體形式,各種缸體形式簡圖,,,一般式實例,一般式實例,20,缸蓋概述,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitati

31、on, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,缸蓋作用: ★ 配氣機構的安裝本體 ★ 密封缸孔上部，并與活塞頂部和缸孔形成燃燒室 ★ 承受發(fā)動機工作時可燃混合氣產生的氣體力 ★ 承受周期性的熱沖擊,典型缸

32、蓋結構圖,21,缸蓋燃燒室分類,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for i

33、ndustrial property rights.,,,,發(fā)動機燃燒室按照缸蓋部分燃燒室的形狀可常分為以下三種:楔形燃燒室: 結構簡單、緊湊，在壓縮終了時能形成擠氣渦流，但對于HC排放不利盆型燃燒室: 結構簡單，但不緊湊半球形燃燒室：結構更加緊湊，散熱面積小，有利于燃料完全燃燒，排放控制好,各種典型燃燒室簡圖,22,曲柄連桿機構概述,Department | 11/05/2010 | © Robert Bosch G

34、mbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,曲柄連桿機構概述: ★ 曲柄連桿結構主要包含活塞連桿組和曲

35、軸飛輪組兩大部分 ★ 曲柄連桿機構的主要作用是把活塞的直線往復運動轉變?yōu)樾D運動 并輸出動力,23,活塞連桿組概述,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, dist

36、ribution, as well as in the event of applications for industrial property rights.,,,,活塞連桿組概述: ★ 活塞連桿組主要包含活塞、活塞環(huán)、活塞銷、連桿總成和連桿軸瓦等 ★ 活塞連桿組的主要作用是承受氣缸中的氣體爆發(fā)壓力，并將此力傳遞給曲軸,活塞連桿組典型構成,24,曲軸飛輪組概述,Department | 11/05/2010 |

37、69; Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,曲軸飛輪組概述: ★ 曲軸飛

38、輪組主要包含曲軸、主軸瓦和飛輪(液力變矩器)等零件 ★ 曲軸飛輪組的主要作用是承受活塞連桿組傳遞來的力,并由此造成繞其 本身軸線的力矩,輸出旋轉運動,曲軸飛輪組典型構成,25,配氣機構概述,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitati

39、on, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,配氣機構的作用: ★按照發(fā)動機各缸工作循環(huán)和點火次序的要求，將曲軸的旋轉傳遞給凸輪軸。 ★凸輪軸上的凸輪適時地控制相應的氣門打開或關閉以完成進排氣動作，使 新鮮空氣及燃燒后的廢氣及時、充分地

40、進入及排出氣缸。,26,配氣相位,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for

41、industrial property rights.,,,,理論上：四沖程發(fā)動機的進氣門當曲拐處在上止點時開啟,在曲拐轉到下止點時關閉;排氣門則當曲拐在下止點時開啟,在上止點時關閉。進氣時間和排氣時間各占180°曲軸轉角。實際上：發(fā)動機的曲軸轉速都很高，活塞每一個行程歷時都很短,這樣短時間的進氣或排氣過程,往往會使發(fā)動機充氣不足或排氣不凈,從而使發(fā)動機的功率下降。早開遲閉：現代發(fā)動機都采用延長進、排氣時間的方法，即分別提

42、前和延遲一定的曲軸轉角，以改善進、排氣狀況，從而提高發(fā)動機的動力性。,配氣相位：就是進、排氣門的實際開閉時刻，通常用相對于上、下止點曲拐位置的曲軸轉角的環(huán)形圖來表示。不同發(fā)動機，由于結構形式、轉速各不相同，因此配氣相位也不相同。,27,配氣機構構造,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding

43、any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,★配氣機構主要由以 下零件構成：1 氣門2 氣門座3 氣門導管4 氣門彈簧5 搖臂6 搖臂軸6 凸輪軸7 凸輪軸正時鏈輪/ 皮帶8 正時

44、鏈/皮帶,28,氣門,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for indust

45、rial property rights.,,,,★氣門的功能是打開和關閉進排氣口和燃燒室之間的口，其由頭部和桿部組成?！餁忾T頭部的形狀有平頂、球面頂和喇叭形頂等?！餁忾T桿呈圓柱形，其與氣門導管配合保證了氣門往復運動的精度，且負責把氣門頭部的熱量傳遞至氣門導管。,★為保證氣門頭與氣門座之間的良好配合，裝配前應注意不要將氣門碰傷或者錯裝，否則將直接導致發(fā)動機漏氣，影響功率甚至無法點火。,29,氣門組其他組件,Department |

46、 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,

47、★氣門彈簧由彈簧座、彈簧保持架和氣門鎖塊固定，用來關閉氣門?！餁忾T座與氣門表面相連，以確保燃燒室的密封性?！餁忾T導管熱壓入缸蓋上的氣門導管孔內，起氣門運動的定向作用。,30,搖臂及搖臂軸,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, re

48、production, editing, distribution, as well as in the event of applications for industrial property rights.,,,,★搖臂的作用是將來自凸輪的力改變方向及行程，傳遞給氣門桿用來打開氣門?！飺u臂軸的作用是固定搖臂，分為進氣搖臂軸和排氣搖臂軸。,搖臂軸,★要注意調整搖臂和氣門間的氣門間隙，過大會導致氣門不能完全打開，過小則當氣門預熱膨脹

49、時氣門不能正確關閉。★搖臂在安裝過程中要注意保護其與凸輪、搖臂軸及氣門的接觸點/面,否則將發(fā)生漏氣，發(fā)動機搖臂抱死并最終導致整機損壞等不良。,31,凸輪軸及其組件,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, e

50、diting, distribution, as well as in the event of applications for industrial property rights.,,,,,★凸輪的作用是在相應的正時打開和關閉氣門。凸輪軸是由各種不同的凸輪構成，為了減少旋轉過程的慣性力，部分凸輪軸為中空結構。,凸輪軸工作原理簡圖,,凸輪軸及其組件,32,凸輪軸及其組件,Department | 11/05/2010 | 

51、9; Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,,★凸輪軸皮帶輪與正時皮帶上的齒相

52、嚙合，以便將曲軸旋轉傳遞到凸輪軸。,★凸輪軸安裝時要注意保護各凸輪面不被損壞，否則將影響到氣門的作動精度，導致漏氣?！镅b配正時皮帶輪時，必須進行調整以確?；钊恢煤蜌忾T開/關正時始終相同。,33,燃油供給系統(tǒng)概述,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exp

53、loitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,,柴油噴射系統(tǒng)的功能：使燃油達到足夠高的壓力；根據發(fā)動機的工況，按一定的規(guī)律，將一定量的燃油噴射進發(fā)動機燃燒室的適合的位置；從而，使發(fā)動機的燃燒過程最優(yōu)。,34,電噴柴油噴射系統(tǒng)的構成,Depa

54、rtment | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property r

55、ights.,,,,傳感器、ECU和執(zhí)行機構三部分組成。裝在發(fā)動機上的傳感器有：（由發(fā)動機廠家提供）⑴ Ne Sensor轉速傳感器；(安裝在飛輪殼上)⑵ G Sensor缸判別傳感器；(安裝在輸油泵上)⑶ Coolant Temp. Sensor冷卻液溫度傳感器；(安裝在出水管上)⑷ Intake Temp.Sensor進氣溫度傳感器；(安裝在進氣管上)⑸ Fuel Temp.Sensor燃油回油溫度傳感器；(安裝在回油連

56、接座上)⑹ Intake Press. Sensor進氣壓力傳感器；(安裝在進氣管上)⑺ Rail Press. Sensor共軌壓力傳感器；(安裝在共軌左側)⑻ Oil Press. Sensor機油壓力傳感器（可選裝電子式機油壓力傳感器）；⑼ 柴油水分報警傳感器（安裝在柴油粗濾器上）（選裝）。,35,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All r

57、ights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,,36,發(fā)動機控制系統(tǒng)簡圖,Department | 11/05/2010 | © R

58、obert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,37,進排氣系統(tǒng),Department

59、| 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,

60、,,作用：根據發(fā)動機的工作定時定量的供給新鮮清潔的空氣，并排出廢氣。,部件： 進氣管 空濾 空壓機 排氣管 增壓器,38,冷卻系統(tǒng),Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, edi

61、ting, distribution, as well as in the event of applications for industrial property rights.,,,,作用：將發(fā)動機的熱量及時傳送出去，以保證發(fā)動機在最適宜的溫度下工作。,部件： 水泵 風扇 散熱器 水箱 節(jié)溫器 出水管等,39,冷卻系統(tǒng),Department | 11/05/2010 | ©

62、; Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,分類：,發(fā)動機的冷卻方式一般可分為

63、“水冷式”和“風冷式”,“水冷式”比“風冷式”冷卻效果要好車用發(fā)動機多采用“水冷式”冷卻系統(tǒng),40,冷卻系統(tǒng),Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as we

64、ll as in the event of applications for industrial property rights.,,,,發(fā)動機過熱，機件的機械強度降低，正常的配合間隙破壞，嚴重時會使發(fā)動機不能正常工作,發(fā)動機過冷，會引起汽油霧化不良，油耗增加，功率下降，磨損加劇,因此發(fā)動機必須通過冷卻系統(tǒng)來保證控制發(fā)動機在正常的溫度范圍內,發(fā)動機是將熱能轉變?yōu)闄C械能的動力機械，在燃燒時，瞬時溫度可達2000度,41,潤滑系統(tǒng)

65、,Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial prope

66、rty rights.,,,,★潤滑系統(tǒng)的作用: 連續(xù)不斷的將一定壓力的機油送到相對運動的各摩擦表面，防止金屬表面直接接觸，減少零件間的摩擦和磨損，并起到冷卻和清除磨粒的作用。,★潤滑系統(tǒng)的主要構成:1 機油控制節(jié)流孔2 機油泵3 油底殼密封墊4 集濾器5 油底殼6 放油螺栓7 機油管8 機油濾清器9 機油濾清器底座10 機油壓力開關,,42,機油潤滑油路,Departme

67、nt | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property right

68、s.,,,,,★機油進入機油濾清器過濾后分為兩路，一路進入缸體和主軸承蓋連接橋的油道，通過曲軸主軸頸與連桿軸頸間的斜油道把機油引到連桿軸頸進行潤滑。 ★另一路機油上行經中間缸蓋螺栓孔進入缸蓋油道，對配氣機構進行強制潤滑，最后通過泄油孔流回油底殼。,,43,起動系統(tǒng),Department | 11/05/2010 | © Robert Bosch GmbH 2010. All rights reserved, also

69、regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.,,,,,發(fā)動機由靜止狀態(tài)轉入工作狀態(tài)的全過程稱之為起動過程。起動機要有足夠的力矩來克服發(fā)動機內部機件的阻力。起動機作為機械動力源，通過電機軸上的