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1、The Application of Turbomachinery to Reciprocating Engines涡轮机械在往复式发动机上的应用,Chapter 6第6章Matching 4-Stroke Diesels与四冲程柴油机匹配,.,吸气线(四冲程发动机才有),转换成压气机特性曲线上的质量流量参数MFP,压气机特性曲线坐标中的吸气线,流量参数,压缩比,Breathing Lines on a Compressor Map,0,25,50,75,100,125,150,175,200,Flow Parameter kg/s*sqrt(K)/MPa,1.0,1.2,1.4,1.6,1.
2、8,2.0,2.2,2.4,2.6,2.8,3.0,3.2,3.4,3.6,3.8,Pressure Ratio,1900 rpm,1300 rpm,压气机特性曲线图上的吸气线,压缩比,流量参数,流量参数,压缩比,Compressor map too large压气机特性曲线图太大,0,25,50,75,100,125,150,175,200,Flow Parameter kg/s*sqrt(K)/MPa,1.0,1.2,1.4,1.6,1.8,2.0,2.2,2.4,2.6,2.8,3.0,3.2,3.4,3.6,3.8,Pressure Ratio,1900 rpm,1300 rpm,压缩
3、比,流量参数,流量参数,压缩比,压缩比,压气机性能曲线上的工作点,工作点的估算,功率,燃油消耗率,空燃比,燃油流量(速),空气流量(速),质量流量参数,知道了MFP，和已有的吸气线，就可得出压缩比PRc,流量参数,sqrt(Tin)/Pin,涡壳的选择对压气机特性曲线上工作点的影响,流量参数,压缩比,大的涡壳,小的涡壳,涡壳通流能力曲线,流量参数,速度参数,小的涡壳，小的涡壳，可提高膨胀比和涡轮功率,增压器转速增大的同时，涡轮流量减小,速度参数,流量参数,在涡轮性能曲线图内运行,扭矩曲线特性,压比,流量参数,发动机在压比不变时，转速从1300上升到1900,压气机质量流量和增压器转速升高,涡端
4、膨胀比增大,发动机温度上升,空燃比增大,涡轮进气温度降低,排气歧管压力增大,转子转速增大,在发动机转速沿着扭矩曲线上升时：,随着发动机转速的上升，进气歧管与排气歧管间的压比减小，泵气损失相应增大,Engine System Performance Limits发动机性能限制,质量流量小，压比又高的情况下，会引起压气机的喘振,压气机或涡轮任何一个发生阻塞时，都会导致增压器效率降低和燃油消耗量增大,空燃比，以及相应的排放问题，(例如烟度),Altitude Performance Criteria高原运行指标,The compressor outlet temperature must not e
5、xceed a set maximum value.The turbocharger rotor physical speed must not exceed a set maximum value.The compressor must not operate in surge.The air-fuel ratio must not fall below a set minimum value.The turbine inlet temperature must not exceeda set maximum value.,Air pressure decreases and also ge
6、nerally temperature decreases,压气机出口温度不能超过设定的最大值,增压器的实际转速不能超过设定的最大值,压气机不能在喘振状态下工作,空燃比不能小于设定的最小值,涡轮进气温度不能超过设定的最大值,大气压力降低,通常情况下温度也降低,HOLW 01.01.10 gives details of turbo speed and temperature limitsHOLW 01.01.10中详细给出了增压器速度和温度的限制,高海拔时的情况如何呢？,绝对压力,海平面状态,高原状态,大气压力,Altitude Means Pressure Ratio Increase压缩比
7、随着海拔高度的上升而增大,MTP,PR,1,2,3,Moving up the engine running line therefore means the Mass Flow Parameter also increases!,goes up because P goes down.,MTP,压缩比增大，工况点沿发动机运行线上升，质量流量参数增大,MTP,因为P减小了,增大,BUT!Absolute pressure goes down但是，绝对压力下降了,Absolute Pressure(bar),1 bar barom,1 bar gauge,2 bar abs,0.5,1,0,Se
8、a Level Conditions海平面状态,2:1 PR,0.5 bar barom,1 bar gauge,1.5 bar abs,3:1 PR,Altitude Conditions(5000m),1.5,2,绝对压力,海拔高度为5000m时,Engine is a VOLUMETRIC device,If absolute pressure drops,then density is lower.如果绝对压力下降，气体密度就会减小,The engine is a volumetric device,so if density is lower,then the mass of air
9、 is less.发动机是一个由容积衡量的设备，如果空气密度降低，空气质量也随之减小,At altitude,the engine has a lower air/fuel ratio,even though the pressure ratio and Mass Flow Parameter have increased.在高原状态下,尽管压比和质量流量都有所增加,但发动机的空燃比还是较小,发动机是用容积衡量的设备,流量参数又减小是因为质量流量的减小,进气管压力降低，质量流量参数增大,Predicting engine-turbocharger performance when operat
10、ing at increased altitudes,Five options:五项原则Intake manifold gauge pressure stays constant and stays on engine breathing line.(This is based upon years of observations and an example is given in text p 6-18)进气歧管表压保持不变并继续停留在发动机吸气线上，这是基于多年的观察经验，可参考第6到18页 中的实例 Holset Guideline:with no test data,assume c
11、ompressor rotor speed parameter will increase at a rate of about:Holset 的指导方针：在没有试验数据的情况下，假定压气机转速按下述比例增大 6%per 1000 metres(1.8%per 1000 feet)at rated speed在额定转速时，每升高1000米增加6%8%per 1000 metres(2.4%per 1000 feet)at torque peak speed 最大扭矩时，每1000米增加8%These numbers vary slightly,depending upon engine and
12、 application.See the calculation procedure in HOLW 01.01.09 这些数值变化甚微，取决于发动机本身及其应用，参考Holw 01.01.09中的计算过程 Run MINIMATCH-takes account of compressor efficiency changes 应用minimatch,分析压气机效率的变化Run GT Power-you will need to model the change in apparent heat release rate as the air/fuel ratio drops with inc
13、reasing altitude.在空燃比随着海拔高度的上升而降低的同时应用GT Power来模拟表面放热率的变化Run the engine in the altitude test cell.在高原试验台架上运行发动机,预测在海拔高度增加时发动机-增压器工作性能,压气机压比,总流量参数,海拔高度-英尺,压气机特性图上的高原运行工况点,Compressor Exit Gauge Pressures压气机出口表压,0,10,20,30,40,50,60,70,0,4000,8000,12000,Altitude-ft,Comp Exit Gauge Pressure,Hg,1800 rpm,1
14、600 rpm,1300 rpm,1000 rpm,压气机出口表压,海拔高度,发动机转速,每1000英尺转子转速变化,实际海拔高度每上升1000英尺时的参数变化,高原运行图,流量参数,压比,额定转速时，单流道涡壳在燃油消耗率方面有1%的优势（涡轮效率要高出3到4 个百分点）,最大扭矩时，双流道涡壳在燃油消耗率方面有1%的优势,双流道涡壳不适于旁通流量大的时候,双流道涡壳对瞬时负载增大有更好的响应能力,旁通阀增压器,旁通阀,进气歧管,中冷,排气歧管,排气管(堆栈),涡轮,压气机,Typically may need more boost here e.g.To reduce smoke at l
15、ow engine speeds,通常是通过提高增压压力来降低发动机低速运转时的烟尘,Use smaller turbine casing to give more work to the compressor hence more boost!,小的涡壳,提供更多的功给压气机从而提高增压压力,Now,because housing is smaller,boost will also increase across the speed range of the engine,现在，由于涡壳小了,在发动机转速由最低上升到最大的过程中增压压力不断升高,Small casing to suit l
16、ow flow at low engine speeds give too much boost at high flow high engine speed,thus leading to over speed,小的涡壳适宜于发动机低速、小流量的状态,但当发动机转速高、流量大时，由于压力上升过大,会导致发动机超速.,BANG!,Small casing also means that engine will have too much boost at even less than max engine speed too much boost can exceed peak cylinde
17、r pressure limits!,小的涡壳使发动机在尚未达到最大转速时，增压压力就已经很大了，甚至会超出气缸可承受的压力极限,Wastegate is set to open at a specific boost pressure to prevent over-boosting the engine.Once open,boost remains approximately constant until the wastegate port becomes choked,设定旁通阀在压比达到一定程度时打开,以防止对发动机增压过度旁通阀一旦打开,压比就近似的保持不变,直到旁通阀孔阻塞为止
18、.,Change in slope of boost vs flow curve indicates wastegate opening point,由二维坐标压比和流量参数构成的斜线的转折点就是旁通阀的开启点,片转阀，便宜，中间位置控制不够,提升阀，贵，中间位置控制较好,排气歧管或涡壳,LINKAGE WEAR POINTS联结磨损点,气体压力,负载力,运动,调节器活塞部件运动示意图,Waste Gate Controls旁通阀控制,Air Pressure Sources 空气压力来源 Compressor Cover 压壳 Intake Manifold(temperature)进气歧管
19、（温度）Brake Tank 制动箱 Exhaust Manifold 排气歧管Air Pressure Controls 空气压力控制 None(use varying pressure of source)没有（采用变化的压力资源）Electronic Valves 电子阀 4 Step 4步 PWM valve(tank air)脉宽调制阀（储存空气）Command valve(boost air)命令阀（增压空气）,增压信号,孔,阀,出口,不可控区域,传统的旁通阀,可调节旁通阀控制区域（低压缩率的弹簧）,转速,扭矩,Command VaIve Integral Modulating W
20、G命令阀-整体调节旁通阀,Command Valve Integral Modulating WG,命令阀-整体调节旁通阀,旁通阀的使用问题与修理,解决办法，轴采用材料Stellite6，420V衬套，连杆的销和衬套采用T400,弹力,调节器空气压力,废气压力,排气歧管或涡壳进气通道,WASTEGATE CLOSED,WASTEGATE OPENING,WASTEGATE CHOKED,通流能力,压比,旁通阀阻塞,旁通阀关闭,旁通阀开启,Affect of turbine control on compressor operation,FG,WG,VG,EGR,high torque,不同涡轮
21、控制方式在压气机特性图上的体现,大扭矩时,进气歧管,排气歧管,中冷,压气机,涡轮,可移动喷嘴环,固定限流板,对可变截面开启的定义,关闭，位置=Y*100/X%,喷嘴面与槽的背面齐平，位置100%,最大流量，位置=Y*100/X%,流量参数,压比,流量参数,效率,恒压比,Creating efficiency vs flow characteristics效率与流量的关系,Actual Dynamometer maps 56%to 218%nozzle gap(expressed as%of turbine wheel tip width)实际的测功图-喷嘴间隙由56%到218%，这个百分比是喷
22、嘴间隙与涡轮顶部宽度的比值,Closing逐渐关闭,Fully open全开,Creating peak efficiency vs flow data for a given expansion ratio:针对给定的膨胀比，做最大效率VS流量图For each expansion ration,select the peak efficiency value and the speed/flow value at which it occurs对于每一个膨胀比，找出最高效率值，以及对应的速度/流量值,膨胀比,总质量流量参数,效率,摆动叶片,移动喷嘴-HX40 低流量VGT,发动机在高工况运
23、行时，突然关闭油门，就会导致压气机发生喘振,ENGINEdisp.=Vd,Aftercooler+pipingvolume=Vac=2-4xVdtime const.Vac/Veng,.,Veng=rpm*Vd/2,.,Compressor,Turbine,Turbo shaft-time constant I*,Transient Surge-First Order Model瞬时喘振-第一种命令模式,Turbo shaft inertia keeps speed(and boostsupply pressure)from changing.,Aftercooler and piping v
24、olumeskeep intake system pressure from changing.,轴惯量维持增压器的转速（增压比）不发生变化,轴,时间常量,压气机,涡轮,发动机排量,中冷器+管道容积,中冷器和空气输送管道维持进气系统压力不变,转速,稳定状态运行,油门由全开状态突然关闭的瞬时现象,流量参数,压气机压比,0.15秒，司机脚部的最快反应速度,稳定状态运行,流量参数,压气机压比,不同燃油切断速度的影响,Levers to Help Reduce Transient Surge有助于减少瞬时喘振的措施,INCREASE the following:Turbocharger shaft i
25、nertia 增大增压器轴的转动惯量Compressor map width 加大压气机性能曲线图的宽度DECREASE the following:Intake manifold air density 降低进气歧管的空气密度The rate at which the fuel is shut off 减小燃油切断的速度Intake manifold volume 减小进气歧管容积,Transeng也可用来模拟瞬时负载增大效应，分析结果在下一页给出。瞬时负载增大现象不只存在于单级涡轮增压的发动机上，在二级涡轮增压系统中，有时低压级的压气机运行曲线被迫向右偏移甚远以至于发生阻塞,TRANSEN
26、 预测负载增大现象,流量参数,压气压比,稳定状态运行,油门在低负载时突然打开的瞬时现象,Effects of wastegated turbocharger efficiency upon fuel consumption旁通增压器对燃油消耗的影响,旁通阀流量百分比,平均燃油消耗率,压气机效率,涡轮效率,空燃比,平均有效制动压力,排气温度,14L发动机,基数,效率提高5%,Rudolph Diesel,In 1893 a German inventor by the name of Rudolph Diesel published a paper entitled The Theory and
27、 Construction of a Rational Heat Engine“.The paper described an engine where air is compressed by a piston to a very high pressure,causing a high temperature.Fuel is injected and ignited by the compression temperature.An engine was built based on that theory the same year and,though it worked only s
28、poradically,Diesel patented it.Within a couple of years the design became the standard for that type of engine and Diesels name was attached to it.Rudolph Diesel died under mysterious circumstances in 1913,vanishing during an overnight crossing of the English Channel on the mail steamer Dresden from
29、 Antwerp to Harwich.Rumours flew about suicide,accidents or foul play but they were all pure speculation.,1893年一个名叫Rudolph Diesel的德国发明家出版了一份标题为：热力发动机的理论与构造”的论文。这份论文描述了活塞压缩空气至高压状态，温度随之升高的发动机，燃料喷入汽缸并由高温压缩的空气点燃。同年，基于这项理论，做了这么一台发动机，尽管这台发动机偶尔才会工作，Diesel还是申请了专利。在2年的时间内这项设计已成为这种类型发动机的标准，并以Diesel的名字来命名。Roudolph Diesel在1913年神秘地去世，在从德累斯顿到安特卫普的邮政汽船穿越应英吉利海峡的那个晚上他突然就消失了。有传言说他是自杀，事故或不正当交易，但这也都只是纯粹的猜测而已。,
