Engine Testing : The Design, Building, Modification and Use of Powertrain Test Facilities

572 Pages·013.321 MB·Russian

by  Анциферова И. В.

Engine Testing
The Design, Building, Modification
and Use of Powertrain Test Facilities
A. J. Martyr
M. A. Plint
AMSTERDAMlBOSTONlHEIDELBERGlLONDON
NEWYORKlOXFORDlPARISlSANDIEGO
SANFRANISCOlSINGAPORElSYDNEYlTOKYO
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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.