论述汽车齿轮动力换档变速器新的控制理念外文献文翻译、中英文翻译
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论述汽车齿轮动力换档变速器新的控制理念外文献文翻译、中英文翻译,外文翻译文献,外文翻译汽车变速器,汽车变速器外文翻译文献,文献中英文翻译,齿轮外文文献翻译,外文文献翻译,中英文翻译,外文文献翻译,中英文翻译外文文献翻译,速器外文文献翻译
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613Outline of a new control concept for power shifting of?xed step ratio automotive transmissionsB JacobsonMachine and Vehicle Design, Chalmers University of Technology, SE-412 96 Go teborg, SwedenAbstract:Power shifting transmissions, e.g. automatic transmissions, are traditionally shifted fromgear A to B by disengaging a clutch belonging to gear A and engaging a clutch belonging to gear B.This paper tries out the idea of employing a third clutch. In practice, such a third clutch can be oneof the clutches which is traditionally used only for other gears. This means that the new concept canbe used with only a control software update in an ordinary gearbox. The trade-oV between comfortand wear, which is experienced in the traditional control concept, becomes less troublesome. Thewear, or the discomfort, can be reduced to roughly half of that corresponding to a traditionallycontrolled upshift. The work ?nds the largest potential in using an extra clutch which belongs to agear higher than the high gear in an upshift. The theoretical study is carried out with a general andsimple model, but a simulation example is added using a more detailed model of an existing gearbox.Keywords:power shift, automatic transmission, control, shift quality, comfort, wearNOTATIONtrad, newtraditional and new control conceptsrespectively0dimensionless quantity (not used for W)A, Bconstants in driving resistance expression1peak value, e.g. cH01in Fig. 3ccapacity of clutch, i.e. a quantityproportional to applied external force ina clutch1BACKGROUNDDdiscomfort, de?ned as time derivative of(dimensionless) torquePower shifting transmissions have the great advantageJmoment of mass inertiaof being able to shift gear without interruption ofmmassmechanical power ?ow. The concept has been in auto-Ppowermotive use since the beginning of the 20th century. Thesspan, i.e. ratio between ratio of twomajority of power shifting transmissions have beengearsimplemented as traditional automatic transmissions withTtorquehydraulic torque converters and hydraulically actuatedWwear in clutch, de?ned as energyclutches and brakes mounted on a gear transmission ofdissipation (dimensionless)planetary type.small positive valueThe mechanical phenomena of power shifting are wellrotational speed (angle/time)described in, for example, references 1 and 2. Howto design the control of gear shifts has been studied in,for example, references 3 to 6. However, none ofSubscriptsthese re?ects on the idea of using more clutches thanclutches A and B, de?ned as the clutch belonging to theeenginegear before the shift and after the shift respectively.in, outinput and output shafts of gearboxrespectivelyip, tpinertia and torque phase respectively2DRIVING FORCES AND AIMS OF THIS WORKL, H, Xclutches for lower and higher gear andextra clutch respectivelyAprobabledevelopmentofautomaticgearboxesThe MS was received on 18 April 2000 and was accepted after revisioninvolves:for publication on 18 December 2000.D04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D614B JACOBSON(a) eliminating the converter, in order to improve fuelthe trade-oV between comfort and wear and ?nd a wayto quantify it in a diagram (see Fig. 4).economy and to reduce weight and cost;For an upshift, a clutch for the lower gear is released(b) introducing more gears, in order to improve fueland a clutch for the higher gear is engaged. Since trans-economy, emission and drivability.missions are often designed with planetary gears, it isThis development is supported by more complex controlnot very obvious which clutch refers to each gear.of the clutches, i.e. control and computer engineeringHowever, reference 1 shows a way to write the equa-and actuator technology. Also sensor technology, e.g.tions in a dimensionless form. Then, the equations canfor estimation of sliding speed in the clutches is of inter-be interpreted as the more simple system shown in Fig. 2.est, even if this has the drawback of implying more cost.Then it is more intuitively clear that the shift is, princi-The present work aims to investigate the potential ofpally, just a matter of switching branches for the powerusing more of the gearbox clutches in a shift than just?ow and that it can be done by operating the twothe clutch for lower gear and clutch for higher gear. Thisclutches involved. Assume constant chassis speed,out=is an example of how improved control possibilities areconstant andout0=1, which is almost the case duringused for exploiting a potential of the mechanical partmost shifts. Also, assume constant engine torque, Te=involved.constant and Te0=1, which is a more serious simpli?-This work is conceptual and it has the followingcation, but it does not change the principal controllimitations:diYculties in the shift. The bottom version in Fig. 2 maytherefore seem to be a special case, but reference 11. No practical veri?cation is made.shows that it covers all reasonable gearbox layouts,2. The clutch for the lower gear is assumed to be con-except for situations with reversed power ?ow, i.e. enginetrolled with perfect timing. This could be consideredbraking, on the lower gear. This engine braking case isas using a one-way clutch, which eliminates the needcovered by dimensionless equations in reference 1 butfor external control.it cannot be given the straightforward physical interpret-3. Only upshifts with clearly positive power ?ow, i.e. noation in Fig. 2. However, the present work does notengine braking, are carefully analysed. Downshiftsclaim to cover the engine braking case.are discussed qualitatively in Appendix 1.In an upshift, clutch L should be released and clutch H4. The theoretical discussion uses a generalized andshould be engaged. Clutch L is supposed to be perfectlysimple system model, i.e. constant engine torquecontrolled, i.e. it is released when starting to take torque(engine torque does not vary with engine speed andload in the wrong direction. This can be designed inis not reduced during gear shift), constant chassispractice with clutch L as a one-way clutch, which elimin-speed, no converter and no elasticity. (The simulationates the need for controlling it. If clutch L is not a one-example is more realistic; see Section 6.)way clutch, there will be practical problems in disengag-The principal idea is that the two control aims (comforting it with appropriate timing, which will lead to eitherand low wear) cannot be ful?lled using only one controltie-up or ?are. These phenomena are discussed in(cH), but adding one more control (cX) could decouplereferences 1 and 2 but they are not considered in thethe aims and thereby reduce the trade-oV. This ispresent work. Tie-up is when too many clutches arevisualized in Fig. 1.engaged, which forces the engine down in speed. Flareis the other way around.The overall control aim is to takeinand Toutfrom3TRADITIONAL SHIFT CONCEPT AND ITSpoint A to point B in Fig. 3. First, the control systemTRADE-OFFincreases cH0and eventually reaches cH0=1. During thisphase, the torque phase, clutch L is unloaded byIn this section, how power shifts are carried out tra-clutch H, which eventually carries the whole load.ditionally will be described. The presentation will onlyHowever, the speeds of the transmission still remain asat the lower gear. In order to change the speeds also,go into as much detail as is needed to be convincing ofFig. 1Visualization of the principal idea for the present workD04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D615OUTLINE OF A NEW CONTROL CONCEPT FOR POWER SHIFTINGFig. 2Generalization and simpli?cation. Upper: possible layout of a gearbox with planetary gear mesh.Lower: interpretation as ordinary gear meshes, based on dimensionless version of equations fromreference 1Fig. 3Reference shift based on traditionalcontrol concept using only clutches L and H. Clutch L is assumedto be controlledwith perfect timing.Clutch H is controlledto avoid steps in Toutand to keep a certainabsolute magnitude, D, of dTout/dt in order to have only one measure of comfortD04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D616B JACOBSONclutch H is further engaged, to a value cH01. Then theSince the shift is described with a single parameter, D,a certain W will be found for each value of D. Since thetorque on the right-hand side of the engine ?ywheel, Tin0,becomes 1, which makes the engine ?ywheel deceler-model is simple and the control of cH0is assumed to bepiecewise linear in time, the following analyticexpressionate. This phase is called the inertia phase, and it endswhen clutch H reaches zero sliding speed.can be found:As seen in Fig. 3, it is assumed that clutch H is con-trolled in such a way that the absolute magnitude of theW=Wtp+Wip=(11/s)22D+J02A11sB2 cH01+1cH01+1derivative of Toutis kept constant at D during the shift.(3)This reduces the number of parameters needed to de?nethe shift fully. The slope D will be used as the measurewhereof discomfort. In practice it is diYcult to ?nd the timingof cH0which makes it exactly 1 when the inertia phaseD=(cH011)2J0(s1)ends. Instead one has to make sure that cH0is slightlyabove 1, i.e. cH0=1+, when this happens, which resultsThis means that a diagram like Fig. 4 can be plotted.in a discontinuous change of Toutfrom cH0/s=(1+)/sHere, in the trade-oV between comfort and wear,increas-to 1/s when the inertia phase ends. This sudden drop ining one increases the other and vice versa. An expressionToutcontributes to the discomfort, but, since it can befor the total shift time can also be found:eliminated through good timing, it is not included in thestudy. It is also a phenomenon that cannot be dealt withttp+tip=11/sD+2J(11/s)cH011(4)using the new control concept. In the more realistic simu-lation example in Section 6, perfect timing is assumed inThe total shift time is also plotted in Fig. 4. Since athe end of the torque phase.normal shift, considering a passenger car during a similarThe two measures discomfort and wear can beshift operation, takes approximately 0.5 s, practicallyidenti?ed in Fig. 3. It is debatable exactly how to quan-reasonable values of D and W are, very roughly, D=tify discomfort, but most should agree that rapid5.5 and W=0.2, which should be noted for comparisonchanges or large steps in traction torque result in badwith the new shift concept in Section 5.comfort. Therefore, discomfort is de?ned as the magni-It should be mentioned that using a conventionaltude of torque change:clutch L instead of a one-way clutch L opens up newpossibilities, in that Toutdoes not have to be reduced allD=KdToutdtK(1)the way to 1/s in the torque phase. However, this involvesa diYcult control problem, where the engine inertia hasSimilarly, the wear phenomena are very complex, but,to be balanced under ?are conditions, i.e. a situationfor this type of clutch, it is more or less accepted thatwhere both clutches slip in the positive direction. Thesethe heat release in the clutch lining is the main problem.solutions are not treated in this paper.For a certain gearbox at a certain shift operation, it isfound practically that wear increases with sliding time,i.e. the heat energy, and not the heat power, is a good4CONTROL DESIGN FOR NEW CONCEPTmeasure of wear. From this reasoning, the followingde?nition of wear is used:In Fig. 5, an extra clutch is drawn, clutch X. In thissection, it will be found that gear X is needed if clutch XW=PTH0relH0dt(2)Fig. 4Trade-oV between discomfort and wear for an upshift using the traditional control concept. Plottedfor span s=1.75 and dimensionless inertia J0=1D04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D617OUTLINE OF A NEW CONTROL CONCEPT FOR POWER SHIFTINGFig. 5Generalization and simpli?cation as in Fig. 2 but also using an extra clutch Xis to be useful during the shift and also how it can bebetween gear L and gear H. The same demands appliedto the case with sXs, whichcontrolled to be comparable with the traditional shift.is contradictory to sX1/s. Accepting the same loss energy, theunloading to zero torque. Equations from reference 1,torque phase could be extended in time, i.e. the comfortextended with the clutch X, givecould be improved. An additional positive eVect is thatthe energy loss would be shared between clutch H andclutch X, which makes it possible to extend the torqueTL0=1cH0sgnA11sXBcX0(5)phase further without reaching some critical value ofenergy loss in either of the clutches H and X.Tout0=1A11sBcH0K11sXKcX0(6)However, this work will not study further the use ofan extra clutch in the torque phase, since the main prob-lem to be solved is found in the inertia phase. Then it isIt is to be investigated whether a clutch X can help inconcluded that WH,tpis identical to the traditional shift,unloading the clutch L. From equation (5), it is cleari.e. the ?rst term in equation (3): WH,tp=(11/s)2/2Dthat such unloading requires sX1 (gear X higher thanand WX,tp=0.gear L) or sX1/s forbeen decreased to 1/s. During the inertia phase, clutch Hthe case with sX1 leads to a new demand: sXs whichis brought in to stick, which means reducing the enginespeed fromin0=1 to 1/s. At the very end of the inertiabinds sXto the interval 1sXin01/s,it would be inconvenient if 1sXs, since the signumwhich eliminates a discontinuity in Tout, which is thesame assumption as for the traditional shift.term would then change sign during the inertia phase.Consider only the two cases:In order to decelerate the engine, it is required thatdin0/dt=(Te0Tin0)/J0Te0,(a) sXs (gear X refers to a gear higher than gear H).Tin0=cH0+sgn(in01/sX) cX01=Te0(7)The diagrams in Fig. 6 can now be drawn. In order toThe output torque will follow the equationhave a shift that is comparable with the traditional shift,a shift principally like that in Fig. 7 is assumed.Tout0=cH0/s+sgn(in01/sX) cX0/sX(8)Fig. 6Plots for ?xed comfort (D=1) and the case where the extra clutch belongs to a higher gear thangear H (sXs). Upper: wear of both involved clutches. Lower: combinations of cH01and cX01. Thesmall circle marks the optimum point, i.e. where the wear, W=min(WH, WX), is minimizedFig. 7Plots for ?xed comfort (D=1) and the case where the extra clutch belongs to a lower gear thangear L (sX1). Upper: wear of both involved clutches. Lower: combinations of cH01and cX01. Thesmall circle marks the optimum point, i.e. where the wear, W=min(WH, WX), is minimizedD04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D619OUTLINE OF A NEW CONTROL CONCEPT FOR POWER SHIFTINGIt can be shown, using equations (1) and (2) and3. Output:corresponding equations for clutch X, that(a) datapointsforthegraphsWH(cX01)andWX(cX01), under the restriction of a certain D(two examples are shown in Figs 8 and 9);WH,ip=J0(11/s)22cH01+1cH01+cX011(9)(b) optimal choice of cH01and cX01, i.e. the choicewhich gives the lowest max(WH, WX) (suchWX,ip=J0(11/s)+(11/sX)(11/s)/22curves are shown in Fig. 10).The analysis behind the plot in Fig. 10 assumes that the6cX01cH01+cX011(10)clutches have a limit for how much they can be appliedin the case sX1. It is formulated as cX015. ItD=AcH01s+cX01sX1sBcH01+cX011J0(11/s)(11)indirectly limits cH01to approximately 13 or 14. Withhigher set limits, better results could be achieved in thewhere the upper of signs and + refers to sXs.The typical shift from Fig. 4 is marked as point A inFig. 10. If it is assumed that this sets an acceptableamount of discomfort (D=5.5), the possible reduction5TRADE-OFFS IN THE NEW CONTROLof wear can be found as point B. Wear is then reducedCONCEPTfrom W=0.2 to approximately W=0.12. On the otherhand, if point A sets an acceptable amount of wear (W=So far, W and D can be calculated, given values of cH010.2), one can ?nd the potential to reduce discomfort toand cX01. However, it is desired to ?nd the limits of whatpoint C. Then the discomfort is reduced from D=5.5is possible in the WD plane, i.e. the trade-oV curve forto D=1.4. These improvements must be consideredcomparison with Fig. 4. Therefore, the algorithm belowsubstantial.is outlined. It is assumed that both clutches involved areFrom Fig. 10, it is clear that the case sXs is the mostequally sensitive to heat dissipation, which means thatpromising one. In broad description, this case uses twothe measure of wear is W=max(WH, WX):principles for reducing the con?ict between wear anddiscomfort:1. Input: a value of D.2. Loop over diVerent values for cX01:1. The heat energy is shared between two clutches, which(a) for each cX01, a cH01can be found, since D isautomatically reduces the wear. This should be intuit-?xed;ively reasonable even without any kinematic analysis.(b) for each cX01, WHand WXcan then also be2. The torque of the extra clutch helps clutch H indetermined;retarding the engine ?ywheel but with less in?uenceChoose the cX01value which gives the lowest W=max(WH, WX).on output torque than clutch H, i.e. less discomfort.Fig. 8Points A mark how to satisfy the requirement Tout0=1/s. Points B mark the situation with thetraditional control concept with the same din/dt. Numerical values used for plots are s=1.75,sX=0.75 and 2.5 respectivelyD04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D620B JACOBSONFig. 9Shift layout for upshift employing an extra clutch, XFig. 10Trade-oV between discomfort and wear for an upshift (s=1.75 and J0=1) using the new controlconcept. Plotted for sX=0.75 and 2.5 respectivelyThis requires a kinematic analysis in order to be fullyof the gearbox. In such a case, clutch X will not supportclutch H in retarding the engine, but it will still reduceunderstood. A simple form of analysis, without anyequations, is shown in Fig. 11.the discomfort in that output torque peaks can bereduced. The other extreme case, when sX=0, corre-sponds to when clutch X works as a brake mounted onThe extreme case when sX= 2 corresponds to whenclutch X works as a brake mounted on the output sidethe input side of the gearbox, which only helps clutch HD04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D621OUTLINE OF A NEW CONTROL CONCEPT FOR POWER SHIFTINGFig. 11Simple example of how clutch X helps clutch H when sXis large, i.e. extreme version of sXsFig. 12Realistic model. System level and brief component description. In the equations, subscripts 1 and 2denote left and right sides of component respectivelyto retard the engine and does not in?uence output7CONCLUSIONStorque. Even these extreme cases have potential toThere is potential bene?t in using an extra clutch duringimprove the trade-oV between discomfort and wear.an upshift in a power shifting transmission. This isshown for a general gearbox, using a dimensionlessmodel and analytical calculations. A more detailed6MORE REALISTIC SIMULATION EXAMPLEmodel veri?es the conclusion for a realistic case, usingdynamic simulation. The control for the new conceptThis section shows fully dynamic simulations with adoes not need to be much more complex than for arealistic vehicle model, including torque converter, drivetraditional shift. Automatic gearboxes contain typicallyshaft elasticities and tyre slip damping. The engine is?ve or six clutches, but only two of these are traditionallymodelled as following a curve of torque versus speed,used in each shift. The idea is to use the extra clutcheswhich is a steady state engine model for a constantonly by introducing new software for control. Thisthrottle position. The control algorithm is implementedshould be a fully realistic modi?cation in the case ofaccording to Appendix 2.modern transmissions with solenoid-actuated clutches.Figure 12 shows a top level diagram of the modelIn the torque phase, use can be made of an extra clutchand Fig. 13 shows the gearbox model. Models arebelonging to a gear between lower gear (gear L) andimplemented in the modelling and simulation softwarehigher gear (gear H). Comfort can be improved byDymola 7. Simulation results are plotted in Fig. 14.extending the torque phase in time. This is possible with-The new shift shows less variation of torque (whichout reaching the critical value for thermal wear of themeans better comfort) and lower maximum energy dissi-clutches. However, in practice, there are seldom thesepation in clutches (less wear). The con?ict between com-kinds of extra clutches available in a gearbox, whichfort and life of clutches is thereby made less seriousmakes the practical potential in the torque phase lessinteresting.through the use of the new shift control.D04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D622B JACOBSONFig. 13Gearbox subsystem of the realistic model in Fig. 12Fig. 14Simulation results from the realistic modelD04300 IMechE 2001Proc Instn Mech Engrs Vol 215 Part D623OUTLINE OF A NEW CONTROL CONCEPT FOR POWER SHIFTING7 Elmqvist, H. Dymola Users Guide, 1999 (Dynasim AB, Lud,For the inertia phase one should consider the diVer-Sweden). Web site: http:/www.dynasim.se.ence between using an extra clutch belonging to a geareither lower than gear L or higher than gear H. Thelatter case is most promising. The potential in increasingAPPENDIX 1comfort and/or decreasing wear is of practical interest,even if there are limitations set by the fact that theConsiderationsfor downshiftsclutches have lower and upper limits of engagement.A patent application is pending for the new controlThis appendix aims to discuss the potential of using anconcept explained in this work.extra clutch during downshifts. A downshift is shown inFig. 15. Similar simpli?cations to the upshift case aremade. These are, ?rstly, that the timing is considered toREFERENCESbe perfect, as in a shift with a one-way clutch on thelower gear, and, secondly, that the clutch control results1 Jacobson, B. Gear shifting with retained power transfer.in only one value of output torque slope, D. A similarDissertation,ChalmersUniversityof Technology,Go teborg,trade-oV between comfort and wear to that in the upshiftSweden, 1993.case applies also to downshifts. If the torque dip in the2 Fo rster,H.J.Getriebeschaltung ohneZugkraftunter-inertia phase is made less deep, it helps comfort. On thebrechnung. Automobil Industrie, October 1962, 6076.other hand, such action would of necessity increase the3 Ibamoto, M., et al. Transitional control of gear shift usingestimation methods of drive torque without a turbine speedshift time and thereby the wear through energy loss insens
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