a r X i v :h e p -t h /9111019v 1 8 N o v 1991HUTP-91/A057
Physics Focus and Fiscal Forces
Sheldon L.Glashow Lyman Laboratory of Physics Harvard University Cambridge,MA 02138Two items are reproduced herein:my ‘Outlook’talk,an amended version of which was presented at the 1991joint Lepton–Photon and EPS Conference in Geneva,and an Open Letter addressed to HEPAP.One is addressed primarily to the European high–energy physics community,the other to the American.A common theme of these presentations is a plea for the rational allocation of the limited funds society provides for high–energy physics research.If my ‘loose cannon’remarks may seem irresponsible to some of my colleagues,my silence would be more so.
11/91
1.OUTLOOK
Just a few months after CERN’s triumphant observations of Z0and W±bosons, Harvard celebrated the centenary of its Je?erson Physical Laboratory.Carlo Rubbia,then one of our most illustrious faculty members,described these discoveries and more:he spoke with gusto of certain curious events—monojets—which could not be explained with the standard model of particle physics.We have learned a great deal since then.There are no inexplicable monojets and there has not been one demonstrable failure of the standard model.QCD and the electroweak theory reign supreme.They o?er a complete,correct and consistent description of all known elementary–particle phenomena.Rubbia is now the director–general of a laboratory that seems forever destined to con?rm the predictions of what we must now call the standard theory.His punishment is?t as a modern–day myth.
Some physicists look upon the current situation as a triumph of human ingenuity, since many of the most puzzling problems of the past are solved.The rich and complex spectroscopy of hadrons is‘understood’at last in terms of the energy levels of a system of two or three interacting quarks,much as the spectroscopy of nuclei is understood in terms of constituent nucleons and that of atoms in terms of electrons.(The quotes are needed since we cannot as yet perform as precise calculations with QCD as we might wish to do.)Similarly,all of the wealth of weak–interaction phenomena is resolved in terms of the gauge interactions of three intermediate vector bosons,whose properties have been found to agree with the predictions of the electroweak theory.
Many questions lie beyond the ken of the standard theory.They remain to be answered and suggest the existence of a more powerful theory.Why are there three fermion families? Why do particles have the masses and mixings they do?Why did nature choose the gauge group SU(3)×SU(2)×U(1)?Look to history,say the optimists.The secrets of the outer atom were exposed at energies of a few eV.Those of the inner atom by X ray studies at energies of a few KeV.The nucleus was explored at MeV energies and evidence for quarks appeared at some GeV.Each great breakthrough required a leap in energy by a factor of 1000.Thus,the next great discovery to be made—the nature of electroweak symmetry breaking and the origin of mass—will be revealed in the multi–TeV domain:at the next great hadron collider.
Other physicists interpret the manifold empirical successes of the standard theory as a tragedy marking the end of an era of exciting discovery.Aside from one missing quark and
the Higgs boson,nothing is left to discover at the high–energy frontier.All that remains is the measurement of the next decimal place.Although we have heard this refrain before, the pessimists also consult the history of our discipline.They point to the great surprising discoveries of the past century,which until recently have sprung upon us every few years: 1890s X rays,rare gases,radioactivity and the electron.
1900s Planck’s h,half–lives,photoelectric e?ect,special relativity.
1910s Cosmic rays,nuclei,the Bohr atom and the bending of starlight.
1920s Hubble shift,quantum theory,spin and the Pauli principle.
1930s Positrons,muons,neutrons,?ssion,continuous beta spectra.
1940s Pions,strange particles,the Lamb shift and the atomic bomb.
1950s Parity violation,pion–nucleon resonance,neutrinos,V?A.
1960s Muon neutrinos,scaling behavior,CP violation,hadrons aplenty.
1970s J/Ψ,neutral currents,tau leptons,charm and beauty quarks.
1980s SN1987a,voids and walls of the universe.
While new and wonderful things are being found out about the universe,there hasn’t been a big surprise in our discipline since the establishment of the third family of quarks and leptons in1977.True,W and Z were?rst produced and detected in the1980s,but their reality came as no surprise.Not for well over a century has there been such an insipid interregnum.So be it.While optimists glory in the success of the standard theory and pessimists bemoan their fate,there remains much to be done:
?Let us not be hasty in assuming its absolute validity:the standard theory must be tested as best we can.With a million Z0events in hand,the theory works just?ne.Will agreement persist when we have ten times that number?Will the deduced value of the muon’s g?2survive the next experimental onslaught?Is the Kobayashi–Maskawa matrix truly unitary?And so on.
?We must learn to exploit the standard model better.Theorists and experimenters must work together to devise more and better ways to extract the consequences of a recalcitrant theory and confront them with experiment.
?We must hope for more surprises and search for them.Nature is not the enemy; complacency is.No physicist should be so arrogant as to believe that her bag of tricks is exhausted,lest the great desert of particle physics become a self–ful?lling prophecy.
?We must worry the weak points of the standard theory.CP violation is surely among them.Another generation of experiments is needed to pin down the fundamental
CP–violation parameters in K0decay.The search for a neutron electric dipole moment must go on.Most importantly,the world needs one(and only one!)B factory powerful enough to explore the question of CP violation in B decay.
?We must extend the burgeoning non–accelerator frontier and not forget that much of what we know about elementary particles once came,and will come again,from disciplines far removed from accelerator–based high–energy physics:
(a)The existence of an alleged17KeV neutrino is?atly inconsistent with the standard
theory.Does it exist or does it not?Discussions at this meeting were inconclusive.
Many experiments,some of them solid,see evidence for it.Many experiments,some of them solid,claim to exclude it.Here is an exciting dilemma!
(b)Does resolution of the solar–neutrino problem demand the existence of mixed and
massive neutrinos?These e?ects lie beyond the minimal17–parameter standard the-ory.However,the case for MSW oscillations as a cure to the problem is far from iron clad.Morrison,for example,is led to conclude that there is no solar neutrino problem.Decisive results from the gallium experiments are awaited with fervor,as are those from future experiments now being planned.
(c)Astronomers have come to the dreadful conclusion that they cannot detect anything
beyond the gravitational in?uences of the dominant form of matter in the universe.
The dark matter may be non–baryonic and unconventional.If so,its identi?cation and investigation lies within the realm of high–energy physics.
The near–term future of elementary–particle physics,largely if not exclusively,de-pends on those large accelerators that are now or soon operating:the?xed target facilities at Fermilab,Brookhaven’s kaon beam,the Tevatron collider,LEP,HERA and the mini B factory at Cornell.I have not the gall to write a guide for the experimenter.Our discipline is open–ended,in the sense that the new and pro?table directions are almost certainly not those that we anticipate.Surprises may lie in wait for experimenters at all of these facilities.
For the long term,our community is almost unanimous in its belief that the next great accelerator must be a hadron collider.SSC is approved and partially funded while an LHC proposal is soon to be put to the CERN council.At the risk of alienating many friends and colleagues,let me consider this issue.?
Giant accelerators,their enormous detectors,and their continuing operations are enor-mously expensive enterprises.We all agree that the world needs one great hadron collider, but two such machines makes no sense at all.The world’s governments,if they knew what we know,should not fund the construction and instrumentation of both machines.There are too many other interesting and important things to do!Although well–intentioned ar-guments have been presented for each accelerator from each side of the Atlantic,the course that is set seems bound for disaster.
Should we prove ingenious(and irresponsible)enough to convince our governments to begin building the two comparable behemoths,these endeavors are likely to starve ongoing research programs in all of physics,and especially in high–energy physics.Money is more–or–less conserved:CERN needs extra support(from member or non–member)nations to build LHC expeditiously,and SSC may not be built without substantial external support. The majority of our colleagues—those who do physics in real time and choose not to live at the very fringe of the high–energy frontier—will need and deserve funds that are almost certainly to be pre¨e mpted by our preoccupation with bigness.
If and when the twin supercolliders begin to do real physics research—which may not happen until the next millenium—there may no longer exist enough of a community of experienced and dedicated high–energy physicists to use them.It is not for reasons of national pride that I believe that SSC is the preferred machine if we have the vision,the scienti?c integrity,and especially,the?scal responsibility to build only one.
?There are technical obstacles in the path of the construction and exploitation of LHC. It requires novel two–in–one magnets operating at nearly ten tesla.Can reliable and ade-quate magnets can be industrially produced at reasonable cost?The physics reach of the LHC is extended by exchanging a compromised collision energy for an intense luminosity, but can appropriate detectors be designed and built to make use of such luminosities?
?There are operational di?culties associated with the construction of LHC.LEP has made a glorious start in its ambitious and exciting program.It has both a higher–luminosity and a higher–energy phase to look forward to.It would be tragic for physics if LHC deployment would hamper,delay or constrain these essential projects.
?There is a serious scienti?c risk associated with the exploitation of LHC.Its collision energy is severely constrained by its need to?t within the LEP tunnel.What if the new physics is accessible at40TeV but not at20TeV?
My dream is of a‘new world order’of cooperation rather than competition for which high–energy physics can lead the way.Let SSC evolve into a truly international project: in funding,instrumentation and administration.CERN is an enormously successful and enviable model.Let SSC?y the?ags of all interested and committed nations and be administered by a representative council much as CERN is.Let it be a machine in America but of the world.My dream is certainly naive,unrealistic and all but impossible to realize. Until recently,the DOE has insisted that SSC be an essentially American enterprise.CERN needs a new initiative to ensure its continued vitality.Nonetheless,I cherish the hope—for the sake of our discipline—that my dream may come true.
Much has been said at this conference about grand uni?cation.Strong,weak and electromagnetic forces are each mediated by gauge bosons.The hypothesis that there is a simple underlying gauge group is irresistably attractive.In minimal SU(5),the curi-ous charges of quarks and leptons are forced upon us and each family corresponds to an anomaly–free representation.Neutrinos are automatically massless and neutral.The ob-served disparity in strength between strong and electric forces sets the symmetry–breaking scale,makes protons practically stable,and evaluates the weak mixing angle.The trouble is in the details:protons are not stable enough and sin2θcomes out a bit too small.
There are many ways in which minimal SU(5)may be modi?ed so as to patch up the problems,?t the data,and save the notion of grand uni?cation.The First Fix:A decade ago,several theorists pointed out that supersymmetrized SU(5)could do the trick[1]. The Second Fix:Both empirical problems could be dealt with by adding to the standard theory one or more split SU(5)fermion multiplets[2].The Third Fix:Perhaps there is an intermediate stage of symmetry breaking involving a semisimple gauge group lying between the unifying group and the group of the standard theory.An intersesting example of such a hierarchy is:
O(10)→SU(3)×SU(2)×SU(2)→SU(3)×SU(2)×U(1).
The intermediate mass scale can be chosen to?t the low–energy values ofα,αs and cosθ[3].For this case,the uni?cation scale is comparable to the Planck energy(neat,but no observable proton decay),and left–right symmetry is restored at roughly a million TeV (useful to generate sensible neutrino masses,but not for new phenomena at LHC or SSC).
Now that LEP data has provided us with an accurate determination ofαs,many workers have refocussed on the rescue of grand uni?cation and the intriguing possibility
that lots of new particles lie almost within reach[4].The results of their analyses are remarkable(and have received lots of attention in the semi–popular press).
Although the failure of minimal SU(5)is now established beyond any possible doubt, its supersymmetrized version is still very much alive.Furthermore,the super–partners of known particles may lie～1TeV and be accessible to the next great hadron collider; and proton decay may be detectable at super–Kamioka.A careful and current analysis of the data[5]is dramatically summarized in?gure(1).?However,the second?x(which does not please supersymmetry fans,but involves many fewer hypothetical and perhaps accessible particles)is also in the running,as?gure(2)demonstrates.The?rst and second ?xes suggest—the input data are not precise enough as yet to use a stronger verb—the possible existence of new physics at soon–to–be accessible energies.However,the third ?x also preserves grand uni?cation with an intermediate mass scale lying well beyond experimental reach.And,there may be other?xes as well.We shall learn more about the various possibilities as data improve,and we cannot emphasize too strongly the importance of those‘pedestrian’experiments,at LEP or HERA,that serve to measure the value of the strong coupling constant.
In summary,let me quote a countryman,‘The game ain’t over’til it’s over.Particle physics is very much alive,both at and away from the highest energies,both at and away from accelerators.Our colleagues who lean toward astrophysics and cosmology have given us a solar neutrino headache and various costly medicines to cure it,gravitational lenses,an indirect con?rmation of gravitational radiation and a hoped–for(but unfunded) search for such waves,supernova neutrinos,a weird large–scale structure to the universe coupled with a perfectly smooth era of recombination,inexplicable burster phenomena, the possibility of unconventional dark matter,and many more surprises and dilemmas to come.Our low–energy colleagues give us monopole constraints,axion searches,an alleged 17KeV neutrino,an exorcism of the?fth force,a precision test of the electroweak theory, and again,more to come.
At the accelerator frontier,there are many important experiments to do and surprises to uncover.Indeed,there is far more to do than we can easily a?ord,especially with the burden of building and instrumenting supercolliders in two continents.The Fermilab collider must be upgraded so that it may do its best to?nd the top,which will be a
primary background to experiments at larger hadron colliders.Fixed–target experiments are needed to measure?′and to search for rare decays and neutrino oscillations.HERA may?nd leptoquarks,but it will certainly lead to precision tests of QCD.LEP,in its present and future avatars,may yield wonderfully inexplicable events,but it o?ers the best tests of the electroweak theory and the best constraints on its variations.A B factory is essential if we are to clarify our understanding of quark mixing and CP violation,while smaller factories which are dedicated to physics at1GeV and at3GeV have important r?o les to play as well.Finally,and in my view most importantly,we must learn how to build a powerful linear electron–positron collider with which to study the TeV domain in a relatively clean environment.
Many of our best theorists are all wrapped up in strings and conformal?eld theory. They believe that a new mathematical framework is needed that lies beyond tried and trusted quantum?eld theory.They are almost certainly right in their belief:the most puzzling‘why questions’cannot even be posed in the standard theory or any of its con-ventional modi?cations.However,their early optimism is gone:most string theorists no longer believe that a theory of everything lurks around the corner.They should not be discouraged.The new theory will come in its time,and today’s theorists may lead us to it kicking and screaming.In the meanwhile,particle physics remains,as it traditionally has been,primarily an exciting and rewarding experimental science.
2.AN OPEN LETTER TO HEPAP
Esteemed colleagues:Some years ago,I became a member of HEPAP.For all I know,I may yet be.I attended the?rst two meetings during my tenure,and no others. The reasons include time pressure and my own irresponsibility,but the primary cause for my delinquency is a strong impression that HEPAP(unlike the CERN Science Policy Committee,in which I served honorably for six years)does not adequately address the needs of the community.Due to the open nature of its meetings,a constituency that re?ects the con?icting self–interests of our several national laboratories,the obligation to follow a?rmly orchestrated agenda,the absence of prior discussions and the lack of executive sessions,di?cult issues are rarely faced and sad truths are withheld or sloughed over.I am led to write this letter—rather than play–act at HEPAP—because of my love for and concern about the discipline of accelerator–based high–energy experimental physics in the United States.
I apologize for this hurried and distraught communication,but I am alarmed by the precipitous decline of a discipline that Americans created and,until recently,dominated. There is not reason nor sense for continuing American domination of the?eld,but we should at least remain as major players.We spend a lot of money on HE physics,but seem to get too little physics done per dollar spent.If we are to argue,as I think we should,for more funding—or even for continuing funding at present levels—we must demonstrate more of a sense of?scal responsibility than we have in the past.At the price of alienating many colleagues and friends,let me say the unsayable:
?The SLD detector at SLAC has been a sink–hole for funds that could have been spent productively:it is a second detector for a machine that will probably never do useful physics.(CERN has analyzed a million,going on ten million,Z0events.SLC has got a few hundred,and won’t do all that better,polarization or no.Face it chums:it’s a brilliant demonstration of a new accelerator technology,but will never be much of a research tool.)Years ago,when the SLD project was initiated,its proponents may have had sound arguments for it.Very soon,however,it became clear to much of the community that the device was pointless.However,once the great bureaucratic ship sets its sails,no agent on Earth can correct its course.Physicists lucky enough to be on board cling blindly to to their challenging tasks no matter that the cruise is to nowhere.For all I know,money is being spent on this useless toy even as I write.
?When the Soudan proton decay detector was?rst proposed,it seemed a good idea. If the larger IMB and Kamioka could detect proton decay,a smaller but more highly instrumented device would have been an invaluable facility.As it turned out many years ago,there was no such signal.It became clear that the Soudan initiative was pointless,as far as its original primary goal is concerned.No matter.The ship plows on.
?Although PEP was in many ways a better instrument than PETRA,its timing was a disaster.Aside from a few physics gems,it came on line far too late to succeed as a forefront accelerator.As my father taught me,if a job’s worth doing,it’s worth doing right...and when it needs doing!
?Years ago,it seemed a good idea to provide the Fermilab collider with a better and bigger(and very expensive)new detector.But a second detector is useful only when there is the potential to exploit the accelerator at which it is to be used.However,we have hardly begun to exploit the CDF detector.With collider runs as far apart as they are, who needs another detector?It’s just one more uncontrollable spigot or useless ship.All
that money could have been used to shore up the decaying university–based infrastructure upon which all of physics research depends.
Enough spilt milk and rotten eggs!High–energy physics in America is threatened by dilution(too many sacred laboratories),by dispersion(too many directions,with little foresight and no corrective capacity)and by the reluctance of our community and its sponsors to perform di?cult but necessary triage.In the future,we must focus more tightly and painfully,or abandon ship.
For sound scienti?c and technical reasons,we all agree that a proton super–collider is our?rst priority.However,SSC will not come on line for physics for a decade.If things continue as they are,there aren’t going to be any American experimenters around who are ready,willing and able to use it.All other priorities are irrelevant and immaterial unless we properly attend to numero uno!
As I talk to my experimentalist friends,I?nd that almost all groups–from the brilliant to the merely sound—are being squeezed out of the business of high–energy physics.Hardly any American graduate students care to board our sinking ships.Yet,if we are to build SSC,we must keep HE physics,especially hadron–collider physics,healthy in the meantime—and there’s lots of good physics remaining to do at the World’s Highest Energy but Rarely Running Accelerator.The training ground for a large hadron collider is a large hadron collider,and we’ve got the only one.We’ve got to‘?nd the top’because it’s likely to be the background to really interesting SSC events.Can anyone doubt that part and parcel of the SSC initiative must be the maximum exploitation of the Fermilab collider.This means that we must have more collider runs sooner and a Main Injector too!
One last word about the SSC,whose balance sheet I’ve never quite understood.It seems that we are depending on massive foreign support for the construction of both the machine and its enormous detectors.We don’t have committments for such support,and we may never do if Europe commits to the LHC and Japan joins their action.Furthermore, it is international lunacy to build and instrument both behemoths.Arguments based on physics goals and technical obstacles convince me that SSC is the better machine to build: LHC is just too small,too hard to build and too hard to instrument.Is the federal govern-ment?nally reaching the sensible conclusion that SSC must be truly internationalized,not only in funding but in management,so that it becomes a facility in America but of and for the World?The search for the secrets of matter and the universe is both glorious and costly.Surely,we must cooperate rather than compete—it’s the way to go,and perhaps the only way.
Acknowledgements
We gratefully acknowledge communications with P.Frampton and U.Amaldi.This work was supported in part by NSF grant PHY-87-14654and by TNRLC grant RGFY9106.
References
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福克斯维修保养使用手 册 集团标准化小组：[VVOPPT-JOPP28-JPPTL98-LOPPNN]
福克斯维修保养使用手册 福克斯上市以来一直受到喜爱驾驶的车主的追捧。不过再好的车也会有瑕疵，好车也要好好保养，对于福克斯的一些常见问题和故障，我们有必要做到知根知底，方便大家更好的用好开好自己的爱车。 故障解读发动机故障指示灯亮福克斯汽车发动机故障指示灯点亮，组合仪表的信息显示中心显示Engine System Fault（发动机系统故障）和Brake light Fault（制动灯故障）。 此故障一般来源于福克斯汽车的制动踏板上安装的两个开关（制动灯开关和制动踏板位置开关），当轻踩制动踏板时，特别是道路交通堵塞时，驾驶员将脚轻踩制动踏板时，可能会出现以下两种情况。 1、制动灯开关起作用，而制动踏板位置开关没有起作用，在经过251这种情况出现后，组合仪表信息显示中心将显示发动机系统故障和制动灯故障。 2、如果制动踏板位置开关起作用，而制动灯开关不起作用，在发动机不熄火连续经过26次这种情况后，组合仪表信息显示中心将显示发动机系统故障和制动灯故障。 PATS（被动防盗）系统福克斯的PATS（被动防盗）系统是目前全球比较先进的车辆防盗系统。此系统设计旨在使TATS设定更复杂，从而使车辆更安全。 PATS是由发动机点火钥匙、防盗警示灯和线圈接收器组成。此系统至少需要2只编程的钥匙，才能启动发动机，并且无法取消PATS系统。一辆福克斯最多可以设定8只钥匙（根据客户需求）。 车主需要注意的是，由于该钥匙内含有晶片，任何磁性物体、其它含晶片的钥匙、信用卡或者其它具有磁性的物体接近钥匙头部都可能导致系统工作失常。 使用解读电子液压动力转向系统福克斯的方向助力系统是电子液压动力转向，无电刷直流电马达。电子液压动力转向系统使用一组电子式驱动液压泵及一组传统齿条与小齿轮转向系统。 控制模块利用内置方向盘内的转向角度传感器来持续的监控转动速度并且估计车速输入的讯号，透过默认值来调整泵的输出率。车主需要特别注意的是方向的角度是受发动机的转速和行驶的车速来控制的，所以请车主在高速驾驶车辆时注意控制好打方向的尺度。
413-13-1 驻车辅助—车辆配备：后驻车辅助413-13-1 章节413-13 驻车辅助—车辆配备：后驻车辅助 适用车辆：2005 Focus 目录页数说明与操作 驻车辅助—车辆配备：后驻车辅助 ................................................................................... 413-13-2 驻车辅助控制模块 ............................................................................................................ 413-13-2诊断与测试 驻车辅助............................................................................................................................ 413-13-3 操作原理........................................................................................................................... 413-13-3检查与确认....................................................................................................................... 413-13-3诊断故障代码(DTC) 索引 ............................................................................................... 413-13-3症状表.............................................................................................................................. 413-13-5定点测试........................................................................................................................... 413-13-5一般程序 方位角度系统检查.............................................................................................................. 413-13-15 后驻车辅助....................................................................................................................... 413-13-15高度系统检查..................................................................................................................... 413-13-17 后驻车辅助....................................................................................................................... 413-13-17拆卸与安装 驻车辅助模块..................................................................................................................... 413-13-19 驻车辅助扬声器— 5-门 .................................................................................................... 413-13-20
章节 412-02 暖气与通风 适用车辆：2005 Focus 目录页数 规格 规格................................................................................................................................... 412-02-2 说明与操作 暖气与通风 ........................................................................................................................ 412-02-3 暖气芯与蒸发器芯风箱 ..................................................................................................... 412-02-3 诊断与测试 暖气与通风 ........................................................................................................................ 412-02-8 拆卸与安装 鼓风机马达 ........................................................................................................................ 412-02-9 暖气芯与蒸发器芯风箱....................................................................................................... 412-02-15 暖气芯— LHD................................................................................................................... 412-02-29 分解与组装 暖气芯与蒸发器芯风箱—车辆配备：手动温度控制........................................................... 412-02-33 暖气芯与蒸发器芯风箱—车辆配备：自动温度控制........................................................... 412-02-38 08/2005 2005 Focus
项目： 正时齿带的检查和更换 一、学习目标 1.能目视检查正时齿带的裂纹、齿面损坏等情况. 2.能正确查找维修手册；拆卸前能认真观察正时记号并将记号对正；能正确拆下和安装正时齿带. 二、场景设计 有AJR 发动机台架、工具台、零件车、木槌、扭力扳手、飞扳、14号开口扳、卡簧钳、短接杆、10号长套筒、19、24号套筒，教学场景如图20-1所示 AJR 发动机台架 工具及工具台 零件车
图20-1正时齿带的检查与更换教学场景 三、知识链接 正时齿带破裂时，如果齿带被咬住，那么气门停在打开状态，同时发动机停止运转；破裂时如果发动机是空转，就意味着在行程顶部的活塞与张开的气门之间存有空隙。这两种情况下的破裂，损坏的只是正时齿带本身。但是，如果发动机是“过盈配合”设计，活塞和气门占据着相同空间，它们之间没有间隙，那么很快就会损坏其他部件，如气门被弯曲，活塞受冲压等。因此，应该了解定期检查、及时更换正时齿带的重要性. 步骤、作业内容及技术要求图解 1、逆时针方向转动机油加 注口盖，并取下机油加注口 盖，放入零件车内。 注意：零件车里无杂物，清 洁干净。发动机表面无灰尘。 图20-2转动机油加注口盖 图20-3取下机油加注口盖
图20-4 机油加注口盖2、用10号加长套筒+短接杆 +小飞扳，按照从外向内 对角线的方法拆下发动 机罩盖螺栓(8个)，并取 下发动机罩盖，放入零件 车内。 图20-5 发动机罩盖 图20-6发动机罩盖2、向上取下机油反射罩， 并放入零件车内。 注意：机油反射罩有机油应 擦拭干净。
4、向外打开正时齿轮上防护 罩上的两个弹簧钢片卡， 并取下正时齿轮上防护 罩，放入零件车内。 图20-8 弹簧钢片卡 图20-9正时齿轮上防护罩。 5、用5号内六角接头+中飞 扳依次取下正时齿轮中 防护罩上的螺栓（3个）， 并取下正时齿轮中防护 罩，放入零件车内。 图20-10 拧松正时齿轮中防护罩上的螺栓
目录 目录 (1) 1.2自动变速器 (2) 1.2.1 4F27E变速器简介 (2) 1.2.2 4F27E变速器内部结构 (2) 1.2.3 4F27E变速器执行元件工作表 (13) 1.2.4 4F27E变速器电子控制系统 (15) 1.2.5 检查与调整 (18)
福克斯自动变速器的控制原理与常见故障 作者：李超年级：2013级汽车检测与维修技术地址：昆明工业职业技术学院 1.2.1 4F27E变速器简介 4F27E自动变速驱动桥，是一种设计用于前轮驱动车辆的电子控制4速变速驱动桥，目前此款变速器装配在1.8L和2.0L排量的福克斯上。 4F27E代表的是： 4 – 4个前进驱动档位 F –前轮驱动 27 –最大输入扭力365 Nm (270 lb-ft) E –全电子控制。 变速器基本参数 1.2.2 4F27E变速器内部结构 4F27E变速箱的机械传动系统的内部结构为：
一组行星齿轮组—复合式行星齿轮组 一组制动器—低/倒档制动器 一组制动带—2/4档制动带 一组单向离合器—低档单向离合器 三组摩擦片式离合器—前进档离合器/倒档离合器/直接档离合器 输出轴差速装置 复合式行星齿轮组 4F27E采用了一组复合式行星齿轮组，该类型的行星齿轮组的特点是前行星轮架与后齿圈一体运转，而后行星轮架与前齿圈一体运转。前后的行星轮和太阳轮则是互相独立的。基本结构如下图所示。
低倒档制动器/单向离合器/行星齿轮组
编号名称编号名称 1 低/倒档制动器活塞11 低档单向离合器 2 低/倒档制动器回位弹簧12 卡环 3 低档单向离合器内座圈13 前齿圈 4 低档单向离合器固定环14 前行星齿轮/后齿圈总成 5 低/倒档制动器波形片15 前行星托架推力轴承 6 低/倒档制动器钢片16 卡环 7 低/倒档制动器摩擦片17 前太阳齿轮 8 低/倒档制动器压片18 前太阳齿轮推力轴承 9 低/倒档制动器卡环19 后行星齿轮总成 10 低档单向离合器固定器20 卡环 前进离合器
关于更换正时皮带的几点看法（姐夫） 车友问： 6W公里(2.5年)保养的时候换了机油,机滤,空气滤,火花塞. 本来想连皮带和汽油滤清器一起换的,但汽滤4S当天正好没货了,就打算下次换了. 皮带报价2000多(包括涨紧轮和惰轮),觉得太贵,就没换,但心里没底,也不知道开到什么时候比较安全. 查资料说老款的2066W公里换皮带,新款的9W公里换 刹车片还挺好,至少还能跑2-3W公里,电瓶也没有问题,都不管了. 答： 正时皮带和刹车片一样，这类东西都是六万公里开始每次保养要检查，并建议更换的。因为他们的价钱都不便宜，更换后使用周期也很长。所以怎么换，何时换，不仅仅要看用车情况，还要结合自已的换车计划来看。 一、用车情况： 正时皮带的正常使用寿命，受三个因素影响：橡胶件的自然老化、转速强烈变化带来的冲击力损伤、长期匀速使用的张力松驰。 （1）橡胶件的自然老化—— 这个，就算你的车放那不开，它也会自然老化的。所以无论你公里数开得再少，也不应该超过五年。 当然，对小六来说，目前还不存在五年的用户 （2）转速强烈变化带来的冲击力损伤—— 这是到一定公里数换皮带的最主要原因。 假设你是出租车，每天在市里不停的停车起步加速减速，那样转速强烈变化的冲击损伤积累的必然就比较多。那样到六万公里，换正时皮带是应该的。 但是，目前我们很多车友大部份路程都是跑的高速公路，车基本上都是匀速行驶的。所以转速强烈变化的冲击损伤积累就很少。 所以，这样的车友，正时皮带用到八万公里左右是没有任何问题的。如果平时在市内也没有急加速、急刹车的飙车习惯，那正时皮带用到九万公里也是没问题。 再看1.4和1.6的发动机比，由于动力上的差距，转速变化的速度会比1.6的慢许多，这样转速强烈变化的冲击损伤积累就更少。
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413-01-1 仪表413-01-1 章节413-01 仪表 适用车辆：2005 Focus 目录页数诊断与测试 仪表................................................................................................................................... 413-01-2 检查与确认....................................................................................................................... 413-01-2自我诊断模式，配备基本等级仪表车辆........................................................................... 413-01-2自我诊断模式，配备中或高等级仪表车辆 ......................................................................... 413-01-5仪表的配置....................................................................................................................... 413-01-7拆卸与安装 仪表................................................................................................................................... 413-01-9
如何判断汽车正时皮带是否需要更换 汽车正时皮带作为汽车运转的重要部件，皮带连接着各种部件。一旦出现断裂或者打滑等情况，与之相关的空调压缩机、动力转向油泵、交流发电机等都将停止工作。因此掌握如何判断汽车正时皮带是否需要更换尤为重要。 如何判断汽车正时皮带是否需要更换，且看 汽车发动机工作过程中，在汽缸内不断发生进气、压缩、爆炸、排气四个过程，并且，每个步骤的时机都要与活塞的运动状态和位置相配合，使进气与排气及活塞升降相互协调起来，正时皮带在发动机里面扮演了一个“桥梁”的作用，在曲轴的带动下将力量传递给相应机件。有许多高档车为保证正时系统工作稳定，采用金属链条来替代皮带。由于车辆正时齿形皮带断裂后会造成发动机内部气门损坏，危害较大，故一般厂家都对正时皮带规定有更换周期。 由于正时皮带的重要性，厂家通常会根据设计以及实际情况来确定一个推荐的使用寿命，并且建议在推荐使用寿命周期到达的时候更换正时皮带。这个更换周期都会在汽车的使用手册和维修手册中清楚地标明。汽车正时皮带的更换周期一般都是在6万英里到12万英里之间。当然，通常为了安全，厂家给出的推荐更换周期都有一定的余量，皮带的实际使用寿命往往长于厂家的推荐值很多。所以有些用户会推迟更换甚至不更换正时皮带，这是要冒风险的，对于非干涉型发动机，正时皮带断裂一般不会引起其他部件的扩大损失，但是在高速上发动机突然停止工作也是有很大的危险，而对于干涉型的发动机
来说，风险就更大了，发动机几乎肯定会报废。所以按照厂家的建议及时更换正时皮带是非常重要的。 今天的讲座就先进行到这里，如果大家还有什么不明白的地方，可以随时来查询，我们下期为大家准备的车辆保养小知识是讲一讲汽车保养包括哪些项目，希望在这里可以再次看到您的身影。
一）拆卸 注意：记录正时皮带盖螺栓的不同长度。 1．支撑住发动机。 2．拆卸： 发动机辅助传动皮带 ?水泵皮带轮?曲轴皮带轮螺栓 ?曲轴皮带轮 ?正时皮带盖 3．转动曲轴到1号气缸的上止点。确保曲轴链轮、凸轮轴链轮、机油泵链轮和平衡轴链轮正时标记4、5、6、7对齐。 注意：凸轮轴链轮上的定位销8应面朝上。 拧松张紧器螺栓9。将张紧器移离皮带并稍稍拧紧螺栓。 5．拆卸： ?自动张紧装置螺栓 ?自动张紧装置11 ?正时皮带 ?曲轴中心螺栓12 ?曲轴链轮13 ?曲轴导向垫圈14 拧松平衡轴皮带张紧器螺栓15。将张紧器移离皮带并稍稍拧紧螺栓。 7．拆下平衡轴正时皮带 （二）安装 ．确保正时标记5、6、7、22对齐。 注意：凸轮轴链轮上的正时标记应与上气缸盖表面对齐-5。排气链轮标记在凹槽上，但进气链轮标记在齿上。 注意：为检查机油泵链轮是否正确定位：从气缸体拆下塞子23。在孔内插入一个8mm十字螺丝刀。确保螺丝刀从气缸体表面插入60mm。如果螺丝刀只能插入20mm：转动机油泵链轮360°。再次插入螺丝刀。 ．拧松平衡轴皮带张紧器螺栓15。顺时针转动张紧器以张紧皮带。拧紧螺栓到15-22N?m。．用手压皮带▼处。皮带应挠曲5-7mm。 ．如果不是：重复操作2-5。 ．安装： ?曲轴链轮导向垫圈14 ?曲轴链轮13 ．将曲轴中心螺栓12拧紧至110-130N?m。 注意：确保曲轴链轮导向垫圈装配正确。装配以前用油涂抹曲轴螺栓螺纹和表面。 ．检查张紧器体11是否泄漏或损坏。如有必要，进行更换。 9．检查推杆突出部分16是否为12mm。如果不是：更换自动张紧装置。 10．慢慢将推杆压入张紧器体11，直到孔对齐。应感觉到有阻力。 注意：在张紧器体下放置平垫圈，以免损坏张紧器体端部螺塞。 11．用合适的销子穿过张紧器体内的孔来固定推杆17。 12．将自动张紧装置安装到气缸体。拧紧螺栓到22-27N?m。 13．从张紧轮开始，按逆时针方向装配正时皮带。 14．拧松张紧轮螺栓9。顺时针转动张紧轮以暂时张紧皮带，拧紧螺栓到43-45N?m。