Engine Testing : The Design, Building, Modification and Use of Powertrain Test Facilities PDF
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Engine Testing The Design, Building, Modification and Use of Powertrain Test Facilities A. J. Martyr M. A. Plint AMSTERDAMlBOSTONlHEIDELBERGlLONDON NEWYORKlOXFORDlPARISlSANDIEGO SANFRANISCOlSINGAPORElSYDNEYlTOKYO Butterworth-HeinemannisanimprintofElsevier Butterworth-HeinemannisanimprintofElsevier TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UK 225WymanStreet,Waltham,MA02451,USA 525BStreet,Suite1900,SanDiego,CA92101-4495,USA Firstedition1995 Secondedition1999 Thirdedition2007 Fourthedition2012 Copyright(cid:1)2012ElsevierLtd.Allrightsreserved. Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmittedin anyformorbyanymeanselectronic,mechanical,photocopying,recordingorotherwise withoutthepriorwrittenpermissionofthepublisher PermissionsmaybesoughtdirectlyfromElsevier’sScience&TechnologyRights DepartmentinOxford,UK:phone(+44)(0)1865843830;fax(+44)(0)1865853333;email: permissions@elsevier.com.Alternativelyyoucansubmityourrequestonlinebyvisitingthe Elsevierwebsiteathttp://elsevier.com/locate/permissions,andselectingObtainingpermis- siontouseElseviermaterial Notice Noresponsibilityisassumedbythepublisherforanyinjuryand/ordamagetopersonsor propertyasamatterofproductsliability,negligenceorotherwise,orfromanyuseoroper- ationofanymethods,products,instructionsorideascontainedinthematerialherein.Because ofrapidadvancesinthemedicalsciences,inparticular,independentverificationofdiagnoses anddrugdosagesshouldbemade BritishLibraryCataloguinginPublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailabefromtheLibraryofCongress ISBN–13:978-0-08-096949-7 ForinformationonallButterworth-Heinemannpublications visitourwebsiteatbooks.elsevier.com PrintedandboundintheUS 1213141516 10987654321 Foreword to the Fourth Edition Theoriginalintentionofmyselfandmylateco-authorofthefirsttwoeditions, Mike Plint, was to pass on to younger engineers our wide, but nonspecialist, knowledge of powertrain testing and the construction of the cells in which it takesplace. I am a product of what is probably the last generation of mechanical engineers tohavebenefitted from afive-yearapprenticeshipwith a UK-based engineeringcompanywhowasabletogiveitstraineeshands-onexperienceof almosteveryengineeringtrade,fromhand-forgingandpatternmaking,through machine-shop practice and fitting, to running and testing of steam and gas turbines andmedium-speed diesel engines. After50yearsofinvolvementinthetestingandcommissioningenginesand transmissions, of designing and project managing the construction of the test equipment and facilities required, this will be the last edition of this book in which I play apart. Thespecialistengineeroftodayissurroundedbysourcesofinformationon every subject he or she may be required to learn in the course of their career. Should they be asked to carry out, or report on the task, for example, of con- verting a diesel engine test cell to also run gasoline engines, the immediate reactionofmanywillbetositinfrontofacomputerandtypetheprobleminto asearchengine.Inlessthanonesecondtheywillbeconfrontedwithoverfour millionsearchresults,themajorityofwhichwillbeirrelevanttotheirproblem andafewwillbedangerouslymisleading.Itismyhopethatoccasionallythose searchesmightfindthisbookandthatnotonlythesectionrelatedtoaproblem will be read. My own research and reader feedback has led me to define three general typesof readership. The first, and for any author the most rewarding, is the student engineers whohavebeengiventhebookbytheiremployersatthestartoftheircareerand whohavereadmostofit,fromstarttofinish,asitwaswritten.Tothosereaders Iapologizeforrepeatingmyselfoncertainsubjects;suchrepetitionistobenefit those who only look at the book to gain specific, rather than general, knowl- edge. The least rewarding is those specialist engineers who, as an exercise in self-reassurance, read only those sections in which they have more expertise thanmyselfandwhomighthavefoundbenefitinreadingsectionsoutsidetheir specialization. Of the remaining readership the most irritating are those who obtainthebookinordertoresolvesomeoperationalorconstructionalproblem xix xx ForewordtotheFourthEdition within a test facility, that would have been avoided had the relevant section beenreadbeforetheworkwasdone.Themostfrequentproblemsfacedbythe latter group, much to my irritation and their expense, are those dealing with someformofcellventilationproblemorthosewho“havealwaysusedthistype of shaft and neverhadanyproblemsbefore”. We all face the problems of working in an increasingly risk-averse world where many officials, representing some responsible authority, seem to consider the operation of an engine test cell to be a risk akin to some experi- mentalexplosivesresearchinstitute,anopinionconfirmediftheyareallowedto witness a modern motor-sport engine running at full power before they drive away,safely, intheir owncars. The subjects covered in this book now exceed the expertise of any one engineer and I have benefitted greatly from the knowledge and experience of manytalentedcolleagues. Becauseoftheriskofunforgivablyforgettingsomeone,Ihesitatetoname all those who have unstintingly answered my questions and commented on someaspectofmywork.However,Iwanttorecordmyparticularthankstothe following: To Stuart Brown, Craig Andrews, Colin Freeman, DavidMoore, and John Holden,withwhomIhavehadthehonorofworkingforsomeyearsandwhose supporthasbeeninvaluable,notonlyintheproductionofthisbookbutinmy working life. To Hugh Freeman for his cheerfully given help concerning modern automotive transmission testing and Ken Barnes for his guidance on theAmericanviewonthesubjectscovered.ToGeorgeGillespieandhisteamat MIRA,andtoengineersfromspecialistcompanies(mentionedintherelevant chapters) who have responded to my requests for information or the use of graphics. MycolleaguesattheSchoolofEngineeringattheUniversityofBradford, ProfessorEbrahimiandByronMason,haveallowedmetokeepuptodatewith engine research and the operation of the latest instrumentation. Of my past colleaguesbasedinGrazspecialmentionmustbemadeofelectricalengineer Gerhard Mu¨eller. Finally, particular thanks to Antonios Pezouvanis of the University ofBradford, who hassupplied both assistance and illustrations. Writingabookisanactofarrogance,forwhichtheauthorpaysdearlyby hours and hours of lonely typing. Thanks must be given to my neighbor and friend David Ballard for proofreading those chapters that had become so agonized over that I was incapable of judging their syntax. Finally, Hayley SalterandCharlotteKentofElsevier,whohavebeenmy“helpoflastresort”, andtomyfamilyfortheirtoleranceconcerningthehoursspentlockedawayon “the bloodybook”. Tony Martyr Inkberrow July 2011 About the Authors A. J. Martyr has held senior technical positions with several of the majortestplantmanufacturersandconsultancyfirmsoverthelast45years.He is now Honorary Visiting Professor of Powertrain Engineering at Bradford University. M.A.PlintdiedinNovember1998,fourdaysafterthepublicationofthe second edition and after a long and distinguished career in engineering and authorship. xxi Introduction This book is not intended to be exclusively of interest to automotive engi- neers, either in training or in post, although they have formed the majority of the readership of previous editions. It is intended to be of assistance to those involved not only with the actual testing of engines, powertrains and vehicles, but also with all aspects of projects that involve the design, planning, building, and major modernization of engine and powertrain test facilities. We are today (2011) at a significant break in the continuity of automotive engine and powertrain development. Such is the degree of system integration withinthemodernvehicle,marine,andgeneratingmachineryinstallationsthat theword “engine” is now frequently replaced in the automotive industries by the moregeneral term “powertrain”. So,whilemuchofthisbookisconcernedwiththedesign,construction,and use of facilities that test internal combustion engines, the boundaries of what exactly constitutes the primary automotive IC power source is becoming increasinglyindistinctashybridization,integrationofelectricaldrives,andfuel cellsystemsare developed. Theunitundertest(UUT)inmostcellstoday,runningautomotiveengines, has to either include actual or simulated vehicle parts and controllers, not previouslythoughtofasenginecomponents.Thisvolumecoversthetestingof theseevolvingpowertraintechnologies,includingtransmissionmodules,inso far as they affect the design and useofautomotivetest facilities. Drivers’perceptionoftheirvehicle’sperformanceanditsdrivabilityisnow determinedlessbyitsmechanicalpropertiesandmorebythevarioussoftware models residing in control systems interposed between the driver and the vehicle’sactuatinghardware.Mostdriversareunawareofthedegreetowhich theirvehicleshavebecome“drivebywire”,makingthem,thedriver,moreof a vehicle commander than a controller. In the latter role the human uses the vehicle controls, including the accelerator pedal, to communicate his or her intention,butitistheenginecontrolunit(ECU),calibratedandmappedinthe testcell,thatdetermineshowandiftheintentioniscarriedout.Inthelifetime of this volume this trend will develop to the point, perhaps, where driver behaviorisregionallyconstrained. Twentyyearsagodrivabilityattributeswerelargelythedirectresultofthe mechanical configuration of the powertrain and vehicle. Drivability and performancewouldbetunedbychangingthatconfiguration,buttodayitisthe testengineersandsoftwaredevelopersthatselectandenforce,throughcontrol “maps”, the powertrain and vehiclecharacteristics. xxiii xxiv Introduction In all but motor sport applications the primary criteria for the selected performance maps are those of meeting the requirements of legislative tests, and only secondarily the needs ofuser profileswithin their targetmarket. BothUSandEuropeanlegislationisnowrequiringtheinstallation,innew light vehicles, of vehicle stability systems that, in a predetermined set of circumstances,judgethatthedriverisabouttolosecontrolor,inconditionsthat areoutsideapre-programmednorm,intervenesand,dependingonone’sview, either takes over powertrain control and attempts to “correct” the driver’s actions, orassists the drivertokeep a conventionalmodelofvehiclecontrol. A potential problem with these manufacturer-specific, driver assistance systems is their performance in abnormal conditions, such as deep snow or corrugatedsand,whendrivers,fewofwhomeverreadthevehicleusermanual, may be unawareofhow orif the systems should beswitched on or off. Similarly, on-board diagnostic (OBD) systems are becoming mandatory worldwide but their capabilities and roles are far exceeding the legislatively required OBD-11 monitoring of the performance of the exhaust emission controlsystem.Suchsystemshavethepotentialtocauseconsiderableproblems tothetestengineerriggingandrunninganypartofanautomotivepowertrainin the test cell (see Chapter11). The task of powertrain and vehicle control system optimization known as powertrainandvehiclecalibrationhasledtothedevelopmentofakeynewrole of the engine test cell, a generation of specially trained engineers, test tech- niques,and specializedsoftware tools. The task of the automotive calibration engineer is to optimize the perfor- mance of the engine and its transmission for a range of vehicle models and drivers, within the constraints of a range of legislation. While engines can be optimizedagainstlegislationinthetestcell,providedtheyarefittedwiththeir vehicle exhaust systems, vehicle optimization is not such a precise process. Vehicle optimization requires both human and terrain interfaces, which intro- ducesanotherlayerofintegrationtothepowertrainengineer.Thesame“world engine” may need to satisfy the quite different requirements of, for example, a German in Bavaria and an American in Denver, which means much power- traincalibrationworkisspecifictoavehiclemodeldefinedbychosennational terrain and driverprofiles. This raises the subject of drivability, how it is specified and tested. In this book the authorhas, rather toowordily, defined drivabilityasfollows: Foravehicletohavegooddrivabilityrequiresthatanydriverandpassengers,providing theyarewithintheusergroupforwhichthevehiclewasdesigned,shouldfeelsafeand confident, through all their physical senses, that the vehicle’s reactions to any driver input, during all driving situations, are commensurate to that input, immediate, yet sufficientlydampedand,aboveall,predictable. Testing this drivability requirement in an engine or powertrain test bed is difficult,yetthedevelopmentworkdonethereincangreatlyaffectthecharacter Introduction xxv oftheresultingvehicle(s);therefore,theenginetestengineermustnotworkin organizational ordevelopmental isolation fromthe usergroups. AproxyfordrivabilityofICengine-poweredvehiclesthatiscurrentlyused isasetofconstraintsontherateofchangeofstateofengineactuators.Thus, within the vehicle’s regions of operation covered by emission legislation, “smoothness”ofpowertrainactuatoroperationmaybeequatedwithacceptable drivability. The coming generation of electric vehicles will have drivability charac- teristics almost entirely determined by their control systems and the storage capacity of their batteries. The whole responsibility for specification, devel- opment, and testing this “artificial” control and drivability model, for every combinationofvehicleanddrivertype,willfallupontheautomotiveengineer. Most drivability testing known to the author is based on a combination of subjective judgment and/or statistically compiled software models based on data from instrumented vehicles; this area of modeling and testing will be an interesting anddemanding area ofdevelopmentinthe comingyears. Fortunately for both the author and readers of this book, those laws of chemistryandthermodynamicsrelevanttotheinternalcombustionengineand itsassociatedplanthavenotbeensubjecttochangesincethepublicationofthe first edition over 17 years ago. This means that, with the exception of clarifi- cations based on reader feedback, the text within chapters dealing with the basicphysicsoftestfacilitydesignhasremainedlittlechangedsincethethird edition. Unfortunately for us all, the laws made by man have not remained unchangingoverthelifetimeofanyoneofthepreviouseditions.Theevolution of these laws continues to modify both the physical layout of automotive test cellsandtheworkinglifeofmanyautomotivetestengineers.Wherepossible, this volume gives references or links to sources of up-to-date information concerning worldwide legislation. Legislation both drives and distorts development. This is as true of tax legislationasitisforsafetyorexhaustemissionlegislation.Aconcentrationon CO emission,enforcedviataxintheUK,hasdistortedboththedevelopment 2 of engines and their test regimes. Legislation avoidance strategies tend to be developed, such as those that allow vehicles to meet “drive-by” noise tests at legislative dictated accelerations but to automatically bypass some silencing (muffling) componentsat higheraccelerations. Frommanysitevisitsanddiscussionswithmanagersandengineers,ithas been noticeable to the author that the latest generation of both test facility users and the commissioning staff of the test instrumentation tend to be specialists, trained and highly competent in the digital technologies. In this increasingly software-dependent world of automotive engineering, this expertise is vital, but it can be lacking in an appreciation of the mechanics, physics,andestablishedbestpracticesofpowertraintestprocessesandfacility requirements. Narrowing specialization, in the author’s recent experience, xxvi Introduction has led to operational problems in both specification and operation of test facilities, so no apology is offered for repeating in this edition some funda- mental advice based on experience. Many of the recommendations based on experience within this book have stories behind them worthy of a quite different type of volume. All test engineers livein aworld that is increasingly dominated by digital technology and legal, objective, audited “box-ticking” requirements, yet the outcomeofmostautomotivetestingremainsstubbornlyanalogandsubjective. Atypical requirement placed upon apowertrain test department couldbe: Carryoutsuchtestingthatallowsustoguaranteethattheunitorcomponentwillwork withoutfailurefor150,000miles(240,000km). Suchataskmaybeformalizedthroughtheuseofa“developmentsign-off form”. If and when the prescribed test stages are concluded and without failure, suchaprocedureallowsthattherequiredboxbetickedtoacknowledgethatthe specified requirementcan beguaranteed. Butthetrueresponseisthatwehavesimplyincreasedourconfidenceinthe unit being sufficiently durable tosurviveits design life. Thisnotsosubtledifferenceinapproachtotestresultsappearstotheauthor tobeoneofthedefiningdifferencesbetweenthepresentgeneration,broughtup in a world dominated by digital states and numbers, and a, usually older, generationwhoseworldviewismuchmoreanalogdsuccessfultestoperations will have awell-managed mixture ofboth approaches. Indesigningandrunningtestsitisafundamentalrequirementtoensurethat the test life so far asispossible represents real life. Powertrain test cells had to become physically larger in order to accom- modatethevariousfullvehicleexhaustsystems,withoutwhichthetotalengine performancecannotbetested.Similarly,cellroofandcorridorspacehashadto beexpandedtohouseexhaustgasemissionanalyzersandtheirsupportsystems (Chapter16),combustionairtreatmentequipment,largeelectricaldrives,and batterysimulator cabinets (Chapter 5). Completelynewtypesoftestfacilitieshavebeendeveloped,inparallelwith the development of legislative requirements, to test the electromagnetic emissionandvulnerabilityofwholevehicles,theirembeddedmodules,wiring harnesses, andtransducers (Chapter 18). The testers of medium-speed and large diesels have not been entirely forgotteninthiseditionandinformationcoveringtheirspecialareaofworkis referenced in the index. The final testers of a powertrain, and the vehicle system in which it is installed, are the drivers, the operators, and the owners. The commercial success of the engine manufacturer depends on meeting the range of expec- tationsofthisusergroupwhilerunningahugevarietyofjourneys;therefore,it has always been, and still remains, a fundamental part of the engine test Introduction xxvii engineer’s role to anticipate, find, and ensure correction of any performance faults before the usergroup findsthem. Theowner/driverofthelatestgenerationofvehiclesmayconsiderthatthe majorityofthenewadditionstothepowertrainandvehiclearesecondarytoits prime function as a reliable means of locomotion. It can be argued that the increased complexity may reduce vehicle reliability and increase the cost of fault-findingandafter-marketrepair;OBDsystemsneedtobecomeagreatdeal smarter and more akin to “expert systems”. The author cannot be alone in wondering about the long-term viability of this new generation of vehicles in the developing world, where rugged simplicity and tolerance to every sort of abuseisthe true test of suitability. Thus, new problems related to the function, interaction, reliability, vulnerability,andpredictabilityofanincreasinglycomplex“sumoftheparts” arise totest the automotivetest engineer and developer. Unfortunatelyitisoftentheenduserthatdiscoversthevulnerabilityofthe technologies embedded in the latest, legislatively approved, vehicles to “misuse”. Thismay be because the test engineer may, consciously or unconsciously, avoidtestconditionsthatcouldcausemalfunction;indeed,thefirstindication of such conditions represent the operational boundaries in a device’s control map during itsdevelopment. The ever increasing time pressure on vehicle development has for many years forced testing of powertrain and vehicle modules to be done in parallel ratherthaninseries.Inmodernsystemsthishasnecessitatedincreasedmodule testing using hardware-in-the-loop (HIL) and software-in-the-loop (SIL) techniques,allofwhichrelyontheuseofsoftware-basedmodelsofthemissing components. Using modeling when the device being modeled is available, cheaper and easier to calibrate than the model generator is just one of the developmentsthatraisesomefundamentalquestionsabouttheroleofthetest engineer, the test sequences used, and the criteria used to judge good results from poor ones.
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