发动机结构及工作原理介绍.ppt

《发动机结构及工作原理介绍.ppt》由会员分享，可在线阅读，更多相关《发动机结构及工作原理介绍.ppt（44页珍藏版）》请在三一办公上搜索。

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 property rights.,发动机结构及工作原理介绍,2,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also r

2、egarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,1892 INVENTION-DIESEL,3,柴油机,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,dist

3、ribution,as well as in the event of applications for industrial property rights.,4,发动机分类,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 property rights.

4、,分类方式：点火方式、冲程数、缸数及排列、冷却。,点燃式发动机 压燃式发动机,点火方式,汽油自燃温度高，采用火花塞强制点火，汽油发动机为点燃式发动机。柴油自然温度低，采用高压缩比压燃，柴油发动机为压燃式发动机。,5,发动机分类,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

5、dustrial property rights.,冲程数,二冲程发动机,四冲程发动机,曲轴旋转一周完成一个工作循环。由于换气不彻底，经济性较差，但结构简单，因此在摩托车上广泛使用。,曲轴旋转二周完成一个工作循环。四冲程发动机有独立的进气和排气冲程，换气彻底，在汽车上广泛使用，并已逐渐用于摩托车。,6,发动机分类,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as

6、 well as in the event of applications for industrial property rights.,缸数及排列,L 4 2.4L,V 6 3.0L,V形排列,6缸,排气量,直列发动机,V形发动机,水平对置发动机,7,发动机分类,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

7、 applications for industrial property rights.,进气状态,按进气状态不同，活塞式内燃机还可分为增压和非增压两类。若进气是在接近大气状态下进行的，则为非增压内燃机或自然吸气式内燃机；若利用增压器将进气压力增高，进气密度增大，则为增压内燃机。增压可以提高内燃机功率。,8,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as w

8、ell as in the event of applications for industrial property rights.,工作方式,转子式发动机,活塞式发动机,发动机分类,转子发动机又称为米勒循环发动机。它采用三角转子旋转运动来控制压缩和排放，与传统的活塞往复式发动机的直线运动迥然不同。转子发动机取消了无用的直线运动，因而同样功率的转子发动机尺寸较小，重量较 轻，而且振动和噪声较低，具有较大优势。三角转子把汽缸分成三个独立空间，三个空间各自先后完成进气、压缩、做功和排 气，三角转子自转一周，发动机点火做功三次。还存在气密性、润滑和磨损等一系列技术难题。,9,工作原理,Depart

9、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 rights.,二冲程汽油机工作原理,二冲程柴油机工作原理,10,发动机工作原理,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reser

10、ved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,气缸内油气混合气燃烧产生压力，推动活塞往复运动，通过曲柄连杆机构转化为曲轴的旋转运动进行动力输出。,发动机工作循环,11,发动机示功图,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding a

11、ny disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,12,发动机常用术语,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the

12、event of applications for industrial property rights.,上止点下至点活塞行程燃烧室容积工作容积总容积压缩比=,13,发动机性能指标,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 property righ

13、ts.,发动机的性能指标用来表征发动机的性能特点，并作为评价各类发动机性能优劣的依据。同时，发动机性能指标的建立还促进了发动机结构的不断改进和创新。,一、动力性指标,1.有效转矩,记作 Te，单位为 Nm,2.有效功率,3.发动机转速,用 n 表示，单位为 r/min,4.平均有效压力,单位气缸工作容积发出的有效功称为平均有效压力，记作 Pme，单位为 MPa,14,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduct

14、ion,editing,distribution,as well as in the event of applications for industrial property rights.,二、经济性指标,1.有效热效率,燃料燃烧所产生的热量转化为有效功的百分数称为有效热效率，记作 e。显然，为获得一定数量的有效功所消耗的热量越少，有效热效率越高，发动机的经济性越好。,2.有效燃油消耗率,发动机每输出 1kW 的有效功所消耗的燃油量称为有效燃油消耗率，记作 be，单位为 g/（kWh）。,式中：B发动机在单位时间内的耗油量，kg/h；Pe发动机的有效功率，kW。,15,Department

15、|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.,三、强化指标,强化指标是指发动机承受热负荷和机械负荷能力的评价指标，一般包括升功率和强化系数等。,1.升功率,发动机在标定工况下，单位发动机排量输出的有效功率称为升功率。升功率大，表明每升气缸工作

16、容积发出的有效功率大，发动机的热负荷和机械负荷都高。,2.强化系数,平均有效压力与活塞平均速度的乘积称为强化系数。活塞平均速度是指发动机在标定转速下工作时，活塞往复运动速度的平均值。,四、紧凑性指标,1.比容积,发动机外廓体积与其标定功率的比值称为比容积。,2.比质量,发动机的干质量与其标定功率的比值称为比质量。干质量是指未加注燃油、机油和冷却液的发动机质量。,16,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduct

17、ion,editing,distribution,as well as in the event of applications for industrial property rights.,八、工艺性指标,17,发动机本体概述,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 for

18、industrial property rights.,发动机本体概述:发动机本体主要包含缸盖、缸体等零部件 发动机本体既是发动机各机构、各系统的装配基体又同时是发动机其它机构/系统的组成部分,缸体,缸盖,18,缸体概述,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 for indus

19、trial property rights.,缸体作用:是发动机的骨架以及相关零部件的安装基体 发动机燃烧室/冷却水道/润滑油道的组成部 承受发动机工作时可燃混合气产生的气体力以及发动机运动件的惯性力 承受周期性的热冲击,典型缸体结构图,19,缸体分类,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 applic

20、ations for industrial property rights.,缸体按照曲轴孔对开的位置是否与缸体下表面(OP面)同一平面可常分为以下三种:一般式:曲轴孔对开位置与缸体下表面同一平面 龙门式:曲轴孔对开位置高于缸体下表面 隧道式：曲轴孔没有对开，适用于安装滚动轴承的组合式曲轴的缸体形式,各种缸体形式简图,一般式实例,一般式实例,20,缸盖概述,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,e

21、diting,distribution,as well as in the event of applications for industrial property rights.,缸盖作用:配气机构的安装本体 密封缸孔上部，并与活塞顶部和缸孔形成燃烧室 承受发动机工作时可燃混合气产生的气体力 承受周期性的热冲击,典型缸盖结构图,21,缸盖燃烧室分类,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,edi

22、ting,distribution,as well as in the event of applications for industrial property rights.,发动机燃烧室按照缸盖部分燃烧室的形状可常分为以下三种:楔形燃烧室:结构简单、紧凑，在压缩终了时能形成挤气涡流，但对于HC排放不利盆型燃烧室:结构简单，但不紧凑半球形燃烧室：结构更加紧凑，散热面积小，有利于燃料完全燃烧，排放控制好,各种典型燃烧室简图,22,曲柄连杆机构概述,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also reg

23、arding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,曲柄连杆机构概述:曲柄连杆结构主要包含活塞连杆组和曲轴飞轮组两大部分 曲柄连杆机构的主要作用是把活塞的直线往复运动转变为旋转运动 并输出动力,23,活塞连杆组概述,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding

24、 any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,活塞连杆组概述:活塞连杆组主要包含活塞、活塞环、活塞销、连杆总成和连杆轴瓦等 活塞连杆组的主要作用是承受气缸中的气体爆发压力，并将此力传递给曲轴,活塞连杆组典型构成,24,曲轴飞轮组概述,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also reg

25、arding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,曲轴飞轮组概述:曲轴飞轮组主要包含曲轴、主轴瓦和飞轮(液力变矩器)等零件 曲轴飞轮组的主要作用是承受活塞连杆组传递来的力,并由此造成绕其 本身轴线的力矩,输出旋转运动,曲轴飞轮组典型构成,25,配气机构概述,Department|11/05/2010|Robert Bosch GmbH 2010.All rights r

26、eserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,配气机构的作用:按照发动机各缸工作循环和点火次序的要求，将曲轴的旋转传递给凸轮轴。凸轮轴上的凸轮适时地控制相应的气门打开或关闭以完成进排气动作，使 新鲜空气及燃烧后的废气及时、充分地进入及排出气缸。,26,配气相位,Department|11/05/2010|Robert Bosch Gm

27、bH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,理论上：四冲程发动机的进气门当曲拐处在上止点时开启,在曲拐转到下止点时关闭;排气门则当曲拐在下止点时开启,在上止点时关闭。进气时间和排气时间各占180曲轴转角。实际上：发动机的曲轴转速都很高，活塞每一个行程历时都很短,这样短时间的进气或排气过程,往往

28、会使发动机充气不足或排气不净,从而使发动机的功率下降。早开迟闭：现代发动机都采用延长进、排气时间的方法，即分别提前和延迟一定的曲轴转角，以改善进、排气状况，从而提高发动机的动力性。,配气相位：就是进、排气门的实际开闭时刻，通常用相对于上、下止点曲拐位置的曲轴转角的环形图来表示。不同发动机，由于结构形式、转速各不相同，因此配气相位也不相同。,27,配气机构构造,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,

29、editing,distribution,as well as in the event of applications for industrial property rights.,配气机构主要由以 下零件构成：1 气门2 气门座3 气门导管4 气门弹簧5 摇臂6 摇臂轴6 凸轮轴7 凸轮轴正时链轮/皮带8 正时链/皮带,28,气门,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,dis

30、tribution,as well as in the event of applications for industrial property rights.,气门的功能是打开和关闭进排气口和燃烧室之间的口，其由头部和杆部组成。气门头部的形状有平顶、球面顶和喇叭形顶等。气门杆呈圆柱形，其与气门导管配合保证了气门往复运动的精度，且负责把气门头部的热量传递至气门导管。,为保证气门头与气门座之间的良好配合，装配前应注意不要将气门碰伤或者错装，否则将直接导致发动机漏气，影响功率甚至无法点火。,29,气门组其他组件,Department|11/05/2010|Robert Bosch GmbH 20

31、10.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,气门弹簧由弹簧座、弹簧保持架和气门锁块固定，用来关闭气门。气门座与气门表面相连，以确保燃烧室的密封性。气门导管热压入缸盖上的气门导管孔内，起气门运动的定向作用。,30,摇臂及摇臂轴,Department|11/05/2010|Robert Bosch GmbH

32、 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,摇臂的作用是将来自凸轮的力改变方向及行程，传递给气门杆用来打开气门。摇臂轴的作用是固定摇臂，分为进气摇臂轴和排气摇臂轴。,摇臂轴,要注意调整摇臂和气门间的气门间隙，过大会导致气门不能完全打开，过小则当气门预热膨胀时气门不能正确关闭。摇臂在安装过程中要注意

33、保护其与凸轮、摇臂轴及气门的接触点/面,否则将发生漏气，发动机摇臂抱死并最终导致整机损坏等不良。,31,凸轮轴及其组件,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 property rights.,凸轮的作用是在相应的正时打开和关闭气门。凸轮轴是由各种不

34、同的凸轮构成，为了减少旋转过程的惯性力，部分凸轮轴为中空结构。,凸轮轴工作原理简图,凸轮轴及其组件,32,凸轮轴及其组件,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 property rights.,凸轮轴皮带轮与正时皮带上的齿相啮合，以便将曲轴旋转传递

35、到凸轮轴。,凸轮轴安装时要注意保护各凸轮面不被损坏，否则将影响到气门的作动精度，导致漏气。装配正时皮带轮时，必须进行调整以确保活塞位置和气门开/关正时始终相同。,33,燃油供给系统概述,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 for industrial property rig

36、hts.,柴油喷射系统的功能：使燃油达到足够高的压力；根据发动机的工况，按一定的规律，将一定量的燃油喷射进发动机燃烧室的适合的位置；从而，使发动机的燃烧过程最优。,34,电喷柴油喷射系统的构成,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 property

37、 rights.,传感器、ECU和执行机构三部分组成。装在发动机上的传感器有：（由发动机厂家提供）Ne Sensor转速传感器；(安装在飞轮壳上)G Sensor缸判别传感器；(安装在输油泵上)Coolant Temp.Sensor冷却液温度传感器；(安装在出水管上)Intake Temp.Sensor进气温度传感器；(安装在进气管上)Fuel Temp.Sensor燃油回油温度传感器；(安装在回油连接座上)Intake Press.Sensor进气压力传感器；(安装在进气管上)Rail Press.Sensor共轨压力传感器；(安装在共轨左侧)Oil Press.Sensor机油压力传感器（

38、可选装电子式机油压力传感器）；柴油水分报警传感器（安装在柴油粗滤器上）（选装）。,35,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 property rights.,36,发动机控制系统简图,Department|11/05/2010|Robert Bo

39、sch 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,进排气系统,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,repr

40、oduction,editing,distribution,as well as in the event of applications for industrial property rights.,作用：根据发动机的工作定时定量的供给新鲜清洁的空气，并排出废气。,部件：进气管 空滤 空压机 排气管 增压器,38,冷却系统,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribu

41、tion,as well as in the event of applications for industrial property rights.,作用：将发动机的热量及时传送出去，以保证发动机在最适宜的温度下工作。,部件：水泵 风扇 散热器 水箱 节温器 出水管等,39,冷却系统,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in t

42、he event of applications for industrial property rights.,分类：,发动机的冷却方式一般可分为“水冷式”和“风冷式”,“水冷式”比“风冷式”冷却效果要好车用发动机多采用“水冷式”冷却系统,40,冷却系统,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 appl

43、ications for industrial property rights.,发动机过热，机件的机械强度降低，正常的配合间隙破坏，严重时会使发动机不能正常工作,发动机过冷，会引起汽油雾化不良，油耗增加，功率下降，磨损加剧,因此发动机必须通过冷却系统来保证控制发动机在正常的温度范围内,发动机是将热能转变为机械能的动力机械，在燃烧时，瞬时温度可达2000度,41,润滑系统,Department|11/05/2010|Robert Bosch GmbH 2010.All rights reserved,also regarding any disposal,exploitation,reprod

44、uction,editing,distribution,as well as in the event of applications for industrial property rights.,润滑系统的作用:连续不断的将一定压力的机油送到相对运动的各摩擦表面，防止金属表面直接接触，减少零件间的摩擦和磨损，并起到冷却和清除磨粒的作用。,润滑系统的主要构成:1 机油控制节流孔2 机油泵3 油底壳密封垫4 集滤器5 油底壳6 放油螺栓7 机油管8 机油滤清器9 机油滤清器底座10 机油压力开关,42,机油润滑油路,Department|11/05/2010|Robert Bosch GmbH

45、 2010.All rights reserved,also regarding any disposal,exploitation,reproduction,editing,distribution,as well as in the event of applications for industrial property rights.,机油进入机油滤清器过滤后分为两路，一路进入缸体和主轴承盖连接桥的油道，通过曲轴主轴颈与连杆轴颈间的斜油道把机油引到连杆轴颈进行润滑。另一路机油上行经中间缸盖螺栓孔进入缸盖油道，对配气机构进行强制润滑，最后通过泄油孔流回油底壳。,43,起动系统,Depar

46、tment|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.,发动机由静止状态转入工作状态的全过程称之为起动过程。起动机要有足够的力矩来克服发动机内部机件的阻力。起动机作为机械动力源，通过电机轴上的齿轮与发动机曲轴后端的飞轮外缘齿圈相啮合，通电后带

47、动飞轮和曲轴转动。发动机起动后，起动机必须立即与飞轮齿圈分离，为此，在起动机上设有脱开机构。起动机的电源来自蓄电池。,44,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 property rights.,ENGINE INTRODUCTION,Thank you!,