`
`.13th CONTROL
`
`1233
`
`3 Advance 15.11515
`
`
`
`. speed; accelerator position;engine coolantfuel. and inlét aii' temperatures, turbOLharger,
`bopstpressuxev5hiql5 311555,control rack(Ir control collar positron Ifo(controloffuélqu‘an-:
`
`(5111 (I(1 311 111-11115 (115551 f1151 1135511011pump apphcahon
`
`. Fuel Quantity and Timing. The. fu51 quantity alone controls a comptassmn ignition.
`éhgihe5 speedand load Th5 intakeairis not throttled as in (1Sparkignition engine.Thequan-
`. (icy of fuel to be deliveredischanged by"mamasmg oi decreming (115lengthof (1151 d5IiV5r‘y:
`(1115per 1561;111:5011 the injection pump, the deliyery timeis confroll5d 15511115 poSitiou’ of the
`control rack on in—line pumps and (heposition of the control(1511111:on distfibutor—-typ5 pumps'
`A11 ECU~50htrolled actuator15 used to1110115the: control rack or 1115 collar to increase or
`decrease the fuel (1511115111 (11115 Th5 ECU determines the correct1511gtl1 of delivery (im‘e
`
`
`(5xpr5ssedas :1 (1111011011 ofcontrolrackor collar posmon) using p5 '
`' " 51155 mapsbasedon
`
`555115 speed and calculated £1151 quantity. Corrections andJorlinfit 5115 as functions of
`
`1701
`
`1701
`
`

`

`‘1 2.34
`
`CONTROL SYSTEMS
`
`
`
`engine speed temperatureand turbocharger boost pressme are used to modify the delivery
`time. In addition the control 139k:or Collar aetu‘ato‘t Contains a position sensor that provides
`feedback tothe ECU on controller position If the requested position differs from the com-
`manded position,the ECU continues to move the controller via‘the actuator until the com-
`mended and actual position are the same
`The start of injection time ofthe fuel at the cylinde1'1sa function of thewave prepagation
`speed (i.6., the speed of sound) of the fuel from thefuel injection pump to the injector
`Because this time remains a eefista11t3at tncreasmg engine speed thedelivery of fuel at the
`cylindel would be delayedwith reference to crankshaft angle. Therefore, the timing at the:
`injaction pumpmust be advancedrwlthIncreasmg ehgine Speedso that thestart ofinjection
`
`Therefore, precise conti01 of the start 0'11"
`
`Althouahmah‘ysystemsusemechanical
`
`spring-loaded timing device plunger,Theplungertotatesthepump’5. collar ring(for distribu—
`tor typepumps)in the oppositedirectionofthe pumpSrotatio'n which advances the timing
`
`1 702
`
`1702
`
`

`

`111121.11,111111.51
`
`, ENGINE CONTROL
`
`123315
`
`Speed Control. As was mentioned previous1y, for3 CI engine fuel quantity 310ne cont1ols
`the engine‘s speed and load. Therefore presunnng adequate injected fuel quantity, an
`unloaded Cl engine (:33 speed up Out of control and dostroy itself Because ofthis, 3 governor 1
`_is required to 11111111111: engine’smaximum speedI11 addrtron governorsare also used 10115111
`idle and 'cruiSe Control, to 11131111211111 3constant engine or Vehicle, speed 3nd meter the correct
`fuel for cold-starting Fuel15 alsocontrolled as a function of speed and boost pre5sure to limit
`- smoke leVels engine torque3nd exhaustg ' " temperatures011 anclectromcallycontrolledCI
`
`' engine the governor5 functions 3re controlled by the fuel delivery system descnbed p L
`bus-1y Engine speed15 provided by an RPM sensor that monitors theperiod5ofangular seg-
`ments between the reference marks on theengine’5 flywheel or inthe111-line injection pump
`
`‘EGR Control. Rerouting of:eXhaustgase5intothe intake air streamis knownas exhaust gas"
`:reurculatioa (EGR) EGR:reduces the 31111011111 ofo 'ygen in the fresh intakeCharge while
`
`‘ increasmg115 5pecific heat.This lowers combustion
`' peratures 3nd resu1t5111 lower NOx
`f emissions.- However, excessive amounts ofEGR resultin higher emiséion5 of soot (particuv
`5131155), CDand HCS,‘ all due to insufficient 311 Also; the introduction of EGR can 113% an
`, adverse affect:on driveabihty duringCold-engine operationfull-load operation, and atidle It
`:is best,therefore to ControllheEGR ValVe with the ECU Both pneumatically controlled 3nd:
`solenord-controlled EGR Valves 3re inuse The ECU determines whenand how 1111151113611,
`will occur based on engine temperature and accelerator position
`
`Titrboch'arger Boost Pressure ContraL Engines. that have turbochargers benefit signifi- ,
`' cantly from electronic boostpressure control. If only a pneumatavmechanical wastegate15,,
`'i used,onlyone booSt pressure135151fortheentire operatingrange15usedtodiVert the exhaust
`condi‘uons because all the exhaust gases 111115111358 the turbineThe135111,,
`,,cicasedemaust
`
`- backpressure, more turbocharger 1110115111011: residual eXhaustgas inthecylinders, and higher
`chargeairtemperatures
`By conn011mgthe wastegate witha pulse-Width-modulated solenonivalvethe wastegate
`, can be opened at, different pressures depending onthe engine operating conditions There-1 1
`1 fore onlythe level of air charge pressure required15deVe‘lopcd TheeleCtronic.central unit,
`uses information on engine speed and accelerator positionto, reference: 3 data: table and the
` ;:pr; [61 boost pressure (actually, duty cycle of the control valve)is 11616113
`111 On systems
`3 usingintake manifold pressure sensors, 3 5105311loop controlsystem can be deVeloped to
`”compare the specified value with the Incasured value
`
`GIothuaControli Electronic control ofthe glowplugduration.can be handledbVtheECU
`oraseparate control Unit.Input for determining gIOWtime15110111 anengine coolant ternper~
`attire sensor. At. the end of the specified glOW period,thecont
`ller turns out the start indicar
`
`tor light to signalthe driverthat theengine can be started He glow plugs remainenergized
`While the starter isengagedAnengine load monitor is use toswitchoff the glowprocess after
`5131-13111 limit theloads On thebatteryandthe glow, plugs, asafetyoVerride15 also used.
`
`1121.312, Fuel ‘DeIiv‘ery‘SVstems‘
`
`‘ The diesel fuel deliVery systemcomprises a low— and, highrprcssure side On the low-pressure
`side15 the feel tank, fuel filter, fuel supply pump1 overflow ValVe, and fuel 51111pr lines The
`. highpressure side15 initiatedin the plungerand barrelassembly and continues through the
`‘ delivery valVe, high-111135511115, injectionlines, and11115011011 nozzle
`The fuelinjectionpump must, dcliVe1 fuel at a pressure between350 and 1200 bardepend
`ing on the engine5 combustion configuration The quantity and tuning of injection must be‘
`I precisely controlled toachiEVe good mixture quality and to minimizeexhaust ennssmns
`
`1 703
`
`1703
`
`

`

`12.35
`
`CONTROL SYSTEMS
`
`FhellnjectiaanceSs An engine-drivencamshaft (in—line pump)orcam-plate (distributor
`.purhp) drives the injectirm pump3 plunger in the supply directionmeeting pressure in the
`high-pressure gallery. The delivery ValVeresponds to theIncrease inpressure byopening This
`sends a pressure waveto the 1njectron nozzle:at the speedof sound The needle ValVe1n the
`nozzle overcomes the Springforce of:flie injectinnnozzle spring and lifts from itsseat when
`the opening pressure is reached FuelIS the!)injected frém‘ the sprayorifices into theengines
`combustion chamber The injectiOH process ends with the opening oi the spill portin the
`plungerand barrelassemblyThis causesthemeasure in the pump chamber to collapSCwhich
`then causes the delivery Valve to close Due to the,action of thedeliVery valve:relief collar the
`pressurein the injection line:15reduced to the “stand—by pressure.” Thestandéby pressure is:
`determined to ensurethattheinjector nozzle Closesquickly to eliminate fueldribble,and the
`residual pressure VJeVes' in the lines prevent the heights fromreopening.
`
`ABOUT THE AUTHORS
`
`GARY C HIRSCHLIEB is chief engineer, engine management systems, for the Rebert: Bosch
`Corp. HepreViouslyheld VariOUSengineering andsalesresponmbflmcs with BoschIn his ear—
`lier career he Worked as a senior engineer in powertrain deVelopment‘ forFind tractoropera—x
`lions,and asasales engineer- withGTE and asanengineer in plantengineeringfor GMT‘ruck
`and Coach
`»
`-
`~-
`
`‘Robert Bosch Corp Prior t0 lllat she had been an engmeenng projeet
`
`C1351; a self—employed technicalwriter,butnntiI1993,she‘was a senior appli-
`
`1 704
`
`1704
`
`

`

`
`
`CHAPTER 13
`TRANSMISSIONCONTROL
`
`KUrt Neuffer, Wolfgang Bullmer anCl Werner Brehm
`R9be‘rtB95911 GmbH
`
`
`131 INTRODUCTION?
`,
`.
`
`InNoithAmenca and Tapan,80 to 9.0percent ofall passengercat'ssold haVe;automatic trans-
`missions (ATS) butin Europe only 10 to 15percent ofpassengerearssold have ATs There
`are: two main reasons EOr the difference. In Europe dtheis tend to ViesVi ATs, compared to
`manual transmissmns as detrimental to driveab tyand responsiblefor. a somewhat higher
`fuelconsumption. But implementation ofelectroniccomer Conceptshas 1nvahdatcd bothof
`thosearguments.
`Sihte theintroduction of electronic transrmssron confiols unit‘s (TCUs)111 the cal1V 1980s
`by Renault and BMW (together with a ton speed transmisswn from Zahnradfabnk
`
`:Fhednchshafen01 ZF), the acceptance of;the A, rose steeply, even inEurope
`,
`son all newATs are designed With electronic Control. Themarket for.A’1's lSaCllVIdEDd 1th
`stepped:and contmuously vanabletransmissrohs (CVTs) For both types the d11ve1 gets11131131.
`» advantages I11steppedtransnussmns thesmooth shifts can be optimized by the reductmn of
`engine torque(1111ngneat shift, combinedWith the (591160th matched oil pressurefoI the 11:11.2
`tion elements (clutches brakebands). Thereduction of shift shocksto a Very low or eVen to
`an unnotlceable levelhas allowed the deswn of [iVespeedATS where 3 Slightly higher num—
`berofgearShifts occur In today'sstandardsystems, the dIiVer(3311‘ choose betweenbspoi‘tand
`econommdliVeprograms by operating a selector switch In highly soph1shcated neWer syS—
`' terns, the selection can be replaced by the self-adaptation of shift strategiesThis leads not
`, only to better driveabrhty but 3130 toasignificant 1eduction1n the] consumption. Addition-
`ally, awell-matched electronic control of the 1‘91que converter lockup helps toimprOve the
`‘ yield oft‘e ‘verallsystem.Bothautomotiveand t1ansn11851on manufacturers benefitfrom the
`ent sh1ftcharacteristics are easyto implement in software and finish adaptation can be
`achieved 11 datachange leaVing‘the t1‘-ansmlss1onhardwareandTCU unchangedThe r'eduC‘—,
`
`1 lossesin friction elements 1ncreases the life expectancy and enables the opti~-
`' 1mzahon of transmiSSion hardware design
`With the C.VT one of the biggest obstacles to the potential reduction111 fuel consumption
`byoperating the. engine at its Optimal Workingpointis the powe1 loSsitemthe transmission5 -
`
`oil pump 0anWith electronic controlis it possuble toachievethe mom
`”('1 yield by matching
`the oil 111ass~st1eamand oil pressure foI the pulleys to theactual workmgconditions,
`To guarantee the overall economic solutionfo1 an electronically (emailed tIansrnissio‘n
`eithersteppedor CVT the availability ofprec151on electrohydrauhc aetUatOIs1s imperative,
`
`'
`
`13.1
`
`1 705
`
`1705
`
`

`

`13.2,
`
`comaorlsrrsrnms
`
`'
`
`4
`
`
`
`1szrsverMCOMP0NENrs ;
`
`The Componentsof an electronic ttansmiSSiOn controlsystem are a transmission which is:
`adapted to the electronic centrol requirements and an electionic control unit With conic!
`spending;inputsandoutputs and attachedSensor elements.
`‘
`
`13.2.1 TransmiSSion
`
`Ihe greatest share of electronically Controlled transmissions-currently on fire marketconsists
`of four— or fi¥c~speed units With a torque cenVerter lockupclutch,cc‘1mmanded by the Control
`unit Market share for fine—speedtransmissionsis continuously'Increasing-With electronically
`controlled transmisfions: there are numerous possibilities to substitute meChanical and
`hydraulic compenents With electromechanical or electrohydrauhc cornponents One basic
`method15' tosubstitute only theshift point control. In aconventional purehydraulic AT,the
`gear shifts are carried outby mechanical and hydrauliccomponentsThese are controlled by;
`a Centrifugal governor that detents the Vehicle speed, and a wire cable connected to the throt-
`tle plate lever.With an electronic shift point control On the other hand anelectronic.control
`unit detects and controls the 1eleVa‘11t components In the transmissmns hydraulic control
`unit, mechanical and hydraulic components arereplacedby electrohydrauhc controlling elca
`.ments, usuallyin the form of electrohydraulic on/off solenoids This way the number of
`solenoidsas Well asthe control logic, canbe:varied over a Widerange Ferexample, for each
`gear one specific: solenoid canoperate the 1eleVant (111111111 for this gear shift Alternatively,
`i there can be one solenoid for each gear change which15 switched corresponding to the shift
`"command In thisWay, only threesolenoidsare required'in a four~speed transmiSsion In some
`'cutrent designs, the gears are controlled by a logical combination of Solenoidstates. This.
`designneeds onlytWogeai-controllingsolenOids for a tour—Speed nansmission For five-speed
`applications,accordingly, three solenmdsare:required(Table 13 1}
`'
`
`1 TABLE 13.1 Example ofa Gear—Solenoid Combinationfor a FiVe-Speed
`TransmissionApplication
`
`Solenoid 17
`I
`V Solenoidz
`7
`15011311011153
`
`on-
`on:
`on
`off:
`
`off‘
`7
`
`”
`
`‘
`
`1st: gear
`2nd gem
`3111 geai v
`4111 gear
`Sthgear
`
`'
`
`'
`
`"
`
`7
`
`741311
`on;
`0ij
`1111
`(611
`
`'
`
`on;
`off
`off
`oft
`Off
`
`The linraullc pressureis controllcdin this basicapplication by a hydraulic proportional
`
`;
`7
`, ontrolle'd by aWireCableconnected to the throttle plate leiVer. With
`this des1gn,the shiftpoints can be deternnnedby the lectromcTCU resultingin a Wide range
`of freely selectable driving behaviors regarding the shift points It15 also posSible to use dif-J
`ferent shiftmapsactsor‘ding to switch 01sensor signals The mtluence on driving comfort dur-
`,ing gear shiftingin this electronictransmission control application has important lestrictions.
`The only possible an to control shift smoothnessIS withan interface to the electronicengine,
`'nianagement’lhisway, the engine Output torque'is influenced during gear shifting Asystem-
`aticwide-rangecontrol of: the hydraulicpressure during and after the gearshift necessitates
`the replacement of the hydraulic pres‘s’ure governor With an electronically controlled
`hydraulic solenoid. This design allows the use of either a pulseomdth—modulated (PWM)
`solenoid or a pressure regulator The choice of which type of pressure contfol solenoid to
`use results from the requirements concerning Shift comfort under all driving conditions For
`
`1706
`
`1706
`
`

`

`msmIssrcn 6011mm,
`
`1343 .
`
`present—day designs With high requirementsfor shift comfort during the entire life of the
`transmission,at all temperatures and with varying as quality, the analog pressure control
`
`
`
`stdlen‘oidls superiorto the usual PWM solenoid prowling there1s no pressure sensor?
`‘ ‘
`
`ation as a guideline for pressure regulation II1
`apphcation usuallyuses one central control-
`lingelement111the transmission fOr the preSsure regulation to control the;shiftquality
`"
`Inother transmission developments, theshift quality18 further moreased using electroni—
`
`callycontrollablebrake elemenis (brake bands) fer some spetii gar.changes In this case,
`the flywheel effect of the revolvmg elements is limited by an electroniccontrol ofa brake
`. hand according to an algorithmor special timing conditions,
`The most sophisticatedtransmission application to date is so dengned that overrunning
`
`
`clutches are eliminated and gear changesare exclusivelycontrolled by theelectronic control
`
`
`IIith pressure regulator scienoids1This applic on is characterized by extremely high
`deman s on the electronicTCU concerningreal1 [tie belt no: and data handling. The rela—
`tionship: between weight transmissidn outline and transferrable torque has reached a high
`level. Compared to transmissions with overnin cluicht-is5 the necessary fitting dimenSiOnsare
`reduced.
`
`' " catty controlled ATsusually have an electronically commanded torque
`Present elect
`chyerter clutch, WlfiChcan lock up the torqueconverter betvveen theengine output and the
`transnussmninputThe torque converterclutchis activated under certain drivingconditions
`
`requirements oITCC functions and shit ”comfortcaneitherbean on/off solenord a P M
`
`solenoIII 191' a- pressure regulator: Lockmgup thetorque converterelunmates heslip of the
`converter and theefficiencyof the transmission system isincreased Tbs reSults111 an even
`lower fuel consumption forcarsequippedWith AT
`
`' 1322 Electronic Control Unit
`
`Another important componentin electronic transmission control istheelectronic control
`Unitwhichis designed accordingto the requtrements ofthe transnnsswn and thecar envi-
`ronments The electronic control unit can be divided into two main parts; the hardware and
`thecorresponding software.
`
`Hardware The hardware of the electronic controlunit COI‘ISISLSofthe housing,the plug, the
`carrier for the electronic devices, and the devices themselvesThehousing, according to the
`rcqunements, is available as an Unsealed design to; applications inside the passenger com-
`pertinent" (311 within the luggage compartment '1 - sals'o possible to have sealed variants for
`11101111th (renditions inside the engine compartmentor at the bulkhead.The materials for the
`housing can be either various plastics or metals There are many different nonstandardized
`housingson themarket The various outlines and plug configurations differ, depending upon
`the manufacturerofthe electronlcunit. Theplug configuration,1‘e., the number of pins and
`
`The number ofpins:isusuallyless than: 1130. Some centrol unitmanufacturers try tostandard
`ize.theirplugs andhousings throughout all their eleCt‘ronic controlunits stich‘ asengineman-
`This1s important to Slmpilfy and to standardize
`agement ABS tractron control, and oth
`
`the unit production and the tests durin'
`I
`‘ _'
`The carrierfor theelectronic device isusually aconventional printed circuit board(PCB3.
`The number of layerson the PCB depe (ison the application.Fer units with a ComplexdeVI‘Ce
`structure and high demands for elee omagnenc compatibility,multilayer applications are in
`use. Inspecial caries;itis posstbleto useceramicsas a Carrier There are usually some parts of
`theelectronic circuit,resistors forexahrpledesigned asa‘ thickfilm circuit on the hybrid. In
`this case the electronicunit15manufactured as a Solder hybrid or as abond hybridwith direct—
`bended integrated circuit deVices Some single applications exist with aflex—foil as a carrier
`forthe electronic dev1ces Theseapplicationsare limitedtoveryspecralrequirements
`
`1707
`
`1707
`
`

`

`'13 .4
`
`CONTROL SYSTEMS
`
`The 'tizzinsmission control. area; requires genie specially designed eiec’trenie devices, in par-
`ticular, the output stages iorthe actuaitors of pressurefregulationrand'tetqne converter clutch
`cOntrol These actuators? for pressure (30111101 have extremely high demands regarding aden—
`racy ofthe aetnaioif eurfent over the whole temperature range and 1111er all conditionsinde-
`pendentof battery voltage and oveithe enDIe 111131111111.htm are somekneWn applicationsof
`customer-spemfic Integrated circuits or devices. Here, special attention paid to quality and
`reliabilitymien the entire lifetime is necessary to meet the continu0usly increasing quality
`re‘qni eme‘nts of the automotive market. Currentiy, thereis an increasingspread ofDsurface-
`111011171th devices111 transrmssmn control applications This:'is why- the unit si2e;iscontinuously
`decreasing despite an increasmg number 91111111211an
`On the. functional Side the hardware configuratiOn‘ean‘bedivided intopower sappiy, input
`signal transfer circints, ontpnf stages, and microcontroller including peripheral components
`and monitoringandSafety circuits(Fig. 131)Thepower snpply converts the Vehicle battery
`voltage: into a constant voltage required by the electronic devices inside the control unit
`Accordingly; specialattention must bepaid to the piotection of the internal devices against,
`destruction by Dansients from the vehicle electrical system such as load dump, reverse battery
`poiaeity,and voltage peaks; PartiCulaI Attention is 3130 necessary in the design of the elec-
`
`ignition L Vilmemal supply :-
`
`ViBa'tt voltage
`
`
`
`2&9“an
`rf‘dlgital‘s‘ignais:
`inbute' ‘~
`‘
`interfaces
`
`
`
`1.
`
`thematdtfig
`
`actuator
`‘
`output
`stages 1
`
`
`
` mism-
`; 901111111191
`
`'
`
`
`‘lnlerfacefii‘; 2
`
`7
`: Pulse signal
`‘
`l
`i
`'
`
`iinfaflialceysif
`:speed ,
`
`'
`'
`1.191111
`
`T
`gATF
`
`
`
`» 31131095191111
`177 W
`'exle'r‘nal
`,
`““3699
`
`
`Watchdog
`'
`
`
`
`diaQantics
`
`
`'régnél’
`interfacejbr’ ;‘
`
`
`diagnosties
`
`
`
`“(73011311311 "Overview of harszife parts:
`
`1708
`
`V ‘
`
`
`
`
`
`slgha|s
`output
`
`.
`
`.
`
`PEOU:
`1
`
`.1
`
`1708
`
`

`

`
`
`1
`1
`i
`3l
`
`l
`
`l l
`
`L
`
`_
`
`1'
`1
`
`-
`
`
`
`
`
`1
`
`L
`
`L
`if:
`
`1
`
`,TRANSMTSSIONCONTROL
`
`13.5
`
`'
`
`
`
`tronicgtound concept for the control unitespecially where the electromagnefic compatibil— ,
`fly andRFmterteienceis chcer‘n‘eLdThis is very 1111porta‘11t to prevent undesiredgear Shift»
`
`" f L116 troublesomefor (11111615. 0116 partof theinputcircuit is the preparation of the
`
`dig at signalssuch aspositionswitch program selection,11161 11161161011711 switch. A second part.
`
` , transfer ofthe a Lalog signals like ATF temperature and voltages according to poten—
`11011165161 states The third partis the interface to other electronic control units, espLeCially to ‘
`the. engme managementsystem.Here the single signal lines 11611116611 the control units W111 be
`increasingly substituted by 1111ssystems111:6 CAN.-The fourth part 151L116 pieparation of 1:116
`transnnssron—specdicsignals fromthe‘sp edsensorsinside the ;'Etiansmissron
`Th6 calculators hiside‘ 1116central 11 its are usually niicrocontrollersTh6r6al-time require—
`meme and t116 directly addressable pro 6111 storage sir of the sel6ct‘6'd microwntrollers are
`
`determined by. thefunctions ofthe 11L L' missi
`L
`and the car enVironment In present
`
`applications either 8—bit or 16b1t.mlCJGCDDLTLLL
`1 1‘6 11‘ use There are sysle L
`L LL'
`i
`111161ocontrollersin development for new,highly sophisticated control systemswithincreasing
`functional and 6111161116 realtime requirements orgmanng from the transmission concept
`The memory deV1ces fer program and data are usuallyEPROMS Their storageca acity16', T1];
`present applications 1111 to 64 Kbytes Future applications will necesSitate storage 13137163 Up to
`
`128 KbytesThe failure storagesfor diagnostics and the sterageLfoi adaptive data are inson—
`Ventioiiala
`. Latinos,battery voltagesuppliedRAMsThese61611161665111eg beingi‘eplaced
`
`by LEFROMs
`
`Thereare usually watchdogwoods in Varibus configurationsin useregarding safety and
`:Lmonitonng These can be either La second log/performance 1111‘ 660111101161, 21 customer—s
`specific circuitor a circuitwithcommon aVail‘zible devices The output stages can be divided
`into thh-power stages forthe transmmsmn actuator control andlowxpowierstages like lamp
`driversorinterfaces to other electronic controlunits. The low——power ontpn’t stages 2116mostly
`couventionaloutput drivers 6111161111singleor inmultiple applications,WTITC1 are mainlypro-
`tectedagainstshort circuitsand Voltage overloads.
`For the transmission solenoid control specialoutput stages are necessary, and they are,
`.L spemalwed for operation withinductive actuators.The pressure regulationduring shiftingin
`Igsonie applications requireshi h‘LLaccuracy aird currentrcgulated output stages ate needed;
`
`"Thesis aremainly designedascustomenspeerficdevicesThe typeandnumberofsolenord out-
`phi: stages depend onthe control philosophy ofthetransmisswn theyare generallyof a spe-
`
`161111 design for specifictransmission applications During th'f" '
`'
`'
`'
`’
` ility and radiofrequencyinter-
`"Signalsattentionmust bepaid tothe electromagnetic comp
`. feren'ce conditions
`'
`Sofmare. Thesoftware Within theelectronic transnnssron eontml system is gamma 11161665-
`"111g importancedueto theincreaSingnumber offunctionsW 611 111 turn, requires increasnig
`
`L'softWaILevolume. The software for the controlunitcan be 111111 6dinto two parts: the program
`and the data;Theptogiam Stiuctureis defined by thefunctions. The data are specific for the '2
`
`, releyant program palts and have to befixed duringthe calibration stage Themost diffic‘iilt
`
`asoitware " quiremenls19111 from the 1661time conditions 6 mmg from the transmlsaon
`
`design Thisisalso the 1116111 Criterion for the selectionof themm rocontroller (Fig132)
`The programis generallymade up in several parts:
`,
`
`' TZQ preparationand filter’’1-Softwareaccordingto the specmlmicrocontroller hardwarew ‘ ;
`
`
`
`
`101 the controllerperipheial1161111165,andinternal softwareseiiuceslike operating systems
`5- Software 60111111V119111 the defined functions Originatingfrom spemhctransmissmn and ear
`functions.
`. -: Parts conceinnigsafetyfunctions like output switCh-off,snbst1111te Values for theinput Sig
`nals, and safetyStates of:themicrocontroller environment in case offailures. Depending on
`the requn‘ei‘nents,there can be a software watchdogora hardiVarepconfigured watchdog
`Circuitin11361116 watchdoginstructionisalso part of the security softwaie
`
`1709
`
`1709
`
`

`

`136
`
`CONTROLASXSTEMS
`
`initialization:
`'ofm‘ie10conirolle _
`
`and controlunit
`
`
`
`‘ifipfitsignals
` '
`Preparation V
`
`
`
`'
`
`‘—
`
`,
`
`
`
`function's:
`
`,
`
`_ caleniation
`
`
`
` - ont‘pnti
`
`Signal,
`Bittanslatign,
`
`fFIGUR'Eim:
`sanwams‘tmcturemexyiew;
`
`.- Diagnostic and eominunication software1111: theself—test ofthecontrol unit and also thetest
`of the control unit environment
`Thesefunctionsarerelated tothe defined functlons of the electronic control systemParts"
`
`
`
`
`
`number of powerful cost-effeetive microcontrollers'
`ity of memory Components with larger1'51 7
`1
`makingitPossibleto use a higherprogr '
`
`an 1ngen1ons structure of sofiware mode
`1
`,
`_.
`-
`
`j
`1 gear shifting with
`> be followed by an effective distribution of f
`
`related time requirementsand event manage;
`"*‘ tructure 1111proves
`
`
`the function 01 the electronic TCU beCause of 1'11
`_‘me—cntical fime—i
`3
`~ ~ ~
`,
`tions during gearshifting.
`1
`
`1710
`
`1710
`
`

`

`TRANSWSSIGWCONTROL
`
`13.7
`
`The second software part data, can he? diVided11110 fixed data whichis related to fixed
`attributes of the system; e.g., thenumber of actuators,and calibration data for system tuning
`The calibration datacan be adapted tochanging parame 1. rs of the ,y tern such asthe engine,
`vehicleand nansmission characteristics The fixing or calibration data takes place during the
`tunmustage ofthe Vehicle and has to be redetennmed foreach typeofvehicle and transmissmn_
`With some applications the calibration data are added to 3 1121516 program duringthe vehicle-
`ptoauctionaccordingto different types of cars bythe so——called end“—ofI111 programrmng This
`meansthatthe units canbe programmed withthe calibration data with dosed rinsingsby a spe: -
`cial interface. The share :1
`'ot'tWare developmentin relation to the totaldevelopmenttime is
`mcrcasmb continuouslyThe ,
`'
`’ uncments for1eel-time behaViorandmemorysize arensmgm.
`
`accordance With the congrderablvmoreasing demands for shittcemtoiit and Selt——learning func-
`tions This requires an ingeniousStructure of thesoftware and an event—related distribution of".
`SoftWare‘models, especrallyduringgearshittingThe rismgsettWare complexity withsimultane—
`'O'uslyIncreasing qualityrequirementscaussshigher; dsnrands1er spfmare quality centre!
`
`13:21.3 ActUatOrs
`
`Electrohydrauhc actuators are impert‘antcomponents otthe electronic transurissioncontrol
`systems2 Continuouslycpeiatirig actuatorsare used to modulatepressiire while switching
`actuators function as supply and discharge VaIVcs tor shift-point controlFigure 133 proVide‘s '
`1 abasic overview of tthetypesof Solenoids.
`.
`,
`Important qualities for the use of actuatorsin ATS are 10w hydratilicresistance to achieve
`highflow rates operation temperature range from —40 to +150 °C, small power loss mini—
`:mizedheat (113811)
`o
`titheECU5outputstages, smallsize andIoW weight, highest rehabil-
`
`
`, A Very nnportantaspectISthat thehardware andsoftware ofthe ECU be developed, tak—
`inginto accounttheelectrical spec1t1c ' ‘e‘ns of thesolenoid to obtain an optimized complete
`syStem'concerning performance and cost“VFor furtherdetailsin design and applicationrefer
`to sec.10.35
`
`It should be meted thatthese characteristi '
`'nbevari" ' dOVeji ‘a widerangeandthatmanyother
`typesofSolenoids existorrareredevelopmer
`.or' thespeciaIrequirementsotnew applications
`
`
`13.1 ,SYSTEM::EUNQTIQNSI
`.
`
`Functions can be designated at- systems functions it the nidiwdualcomponents of the total
`' electronictransmission control System cooperate ethorently to piov1dea desired behavior of
`the transmission and the Vehicle There aredifferentstages0 7 on tronality Which havediffer".
`
`ent‘ effects on (11wing behavior and shift characteristics ( pig7 3.4; n gCneraI thereIS an
`moreasmg COmpICXlty of the System 1elatingto all components to improvethe translation of
`{clriV'e‘r behavrorinto transmrssmn action. That means thatthe expense 0 actuators sensors,
`and links to othercontrol unitsis increasing, as is the expenseofthe TCUsoftware and hard—'
`were in the case of high—level requirements regarding drrveahihty andShift comfort. Figure
`13.4 shows threemain areas These will be discussedin detailin the followingmaterial
`
`13.3.13 Basic Functions
`
`The ‘basmtunctionsof thetranSmissit‘m centrolare the shift pointcontrol the Iockup control,
`engine torquecontrol duringshitting,- related safetyfunctions, and diagnostic fnnCtions tor-'
`
`1711
`
`1711
`
`

`

`Switching actuamrs‘
`
`Cantinuons operation actuators
`
`I;
`
`
`
`
`
`{Yigri’afie FEESSuFC
`1 Solenoid
`
`1"
`
`karma";
`
`Em
`
`
`
`
` ‘Eérlmnifli 7
`high
`
`pr'moxav (lawns/min, mom):
`
`
`High Fluw‘-(fi000cmsimin,‘4noxpa) '
`
`
`
`
`FIGURE 13.3 ‘Electrdhydrafilicxactuzifogs‘fbi automaticitransmissions;
`
`. V'Func‘t'ional contents
`
`
`"Acptan
`
`
`
`
`
`
`
`
`
`
`
`
`
`: Sexfiéaming adaptatl’gh '
`N 7 W
`
`Vlgf shift; strategy to driving 7
`
`
`
`' .eravjbfa
`
`
`
`
`
`
`
`
`: ‘Selfilési'rhfifi adap’té‘tiefi'or’ 7
`
`: shift characteristic aghgrding
`
`
`"to‘VatiatggeVJquacndvltidljg ‘
`
`
`
`
` Bééicfuhaionsv 7 7
`
`‘
`jt fo’r'excellent‘gearchange
`
`
`
`
`FIGUREJBA Reliafipnsfiiplbetween‘dfivixigtcharactefisfic and fungfien CumpleXity.
`
`13.8,
`
`1712
`
`1712
`
`

`

`TRANSMISSIGNCONTRQL
`
`13.9»
`
`
`
`
`
`'i‘gn'lfion ‘ 1"
`Viaaui
`
`
`
`7
`
`1.
`
`'pOSihbfi
`5““th
`
`1
`
`V
`
`l
`digltél‘slgnalsl'
`
`
`‘
`lntenacesz
`
`
`s
`
`
`
`7;",
`
`:EMS
`interface
`
`i
`
`'
`
`m‘icr‘o-
`7
`
`controller
`:
`
`
`
`I
`
`
`
`5159765
`
`'
`
`.
`
`,Sdiema :
`
`7 ..
`
`TSO‘lenQidsl?
`
`
`
`
`
`
`
`
`TATF
`
`,
`
`K4111:
`b11111
`
`7
`
`.1
`
`1‘
`.
`
`analog Signals:
`T ’
`.
`I
`1
`
`interfaces
`1
`
`..
`7
`‘
`:,'Esertar'f
`
`
`
`"
`;
`lhtéiifaéeifgrj‘
`diagnostics
`
`"FIGURE 13.5“ Struo‘ture‘ofa bas‘ictfansmissioxireleutréfiictééntfol unit.
`
`
`external
`watchdog
`
`
`’
`
`“"113 1191119"
`
`érjgi‘lner
`itorq'ue
`regucgtlon
`
`
`
`veh1cle service The pressure control111transm1s51on syr' ems, With- clcctncal operatlng possi-
`,,
`7
`1
`.
`1‘
`and Outside shiftingca 731150 be cons1deredas abasicfunction.
`
`7,
`-5 shows the116cc
`y inputs and outputs as wel1asthe block diagram ofan elec-
`’
`
`trochCU suitable for 1he basic functions
`
`‘
`.
`
`SluftPomt Control Thebasic shift point. Control uses shift mapswhichare defined " ‘ data
`‘inthe unit memory.Theseshiftmapsare: selectable War a Widerange. Theshiftpom mita-
`eed foreach application.
`tionsare made,.1)
`th one hand by the highest adrmsmble engin
`
`
`for duvmg comfort ‘afid.
`
`and, on the» other. hand by the lowest engm ' ”
`'
`‘is practica
`
`.11" se emissionThejnputs ofthe 5111111501111de rmina
`gaze thethrottle pos1t10ntheaccel—
`erator pedalposition,and 1he vehxclespeed (determined bythe transm1ss1on output speed)1
`IFigum‘ 136 shoWs21 types]shiftmap pphcatlonof ‘a fourrspeed transm1ss1on
`' To prevent overly fiequent shlftmg between :tWQ gears 21 hystereSIS betwéen the upshift
`
`
`2111111111: downshiftcharactens 10
`incorporaed Th hysteres1s18 (1111121111111
`11
`1e‘des1redi
`shifting habit of the transmissmn andalternativelyhej ca1' behavior, In theevent that thepar-:
`
`‘
`"
`‘
`1
`'
`'
`'
`'
`alves,t116 electronic
`ECU releases the sh1;t byactivating the related actuators. This can be a direct shiftinto the"
`
`1713
`
`1713
`
`

`

`13110
`
`CONTROL'SYSTEMS
`
`E-ProgramtEcommy)
`
`
`
`load,
`
` Engine
`
`:Outputs‘peed nab-X 1000,
`
`FIGURE 1316' Shift characteristics of a fomLSpeed'applibatiOn.
`
`target gear or by aserial actiyatiOn of specific. aetuators111 a fiXed sequence to the target?Dnear,
`depending on the transrmssmn hardwaredesign
`
`Backup Control/Torque Converter Clutch 3 The torque conVerter Clutch connects both
`functional components ofthe hydraulic converter, the pump and theturbine. The lookup of
`the clutch reduces the power losses coming£10m the torquecenverte'r- shpThis is a perma-
`nent slipbecause it is necessary in principle to have 11 slip betWeen- the pumpwheel and the
`turbine to translate torque from the engine outputto. thetran3niission input Toincrease the
`efhmencyof the: lockup, itis necessary to close the clutchas often