• 专利附录
  • 专利说明
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    • 专利摘要:
    The invention relates to a method for controlling a vehicle (1) in connection with a downhill slope, the vehicle (1) comprising a powertrain (3) with a combustion engine (2); and a waste heat recovery system (10) associated with the combustion engine (2), the waste heat recovery system (10) comprising a working fluid circuit (12); an evaporator (14); an expander (16); a condenser (18); a reservoir (20) for a working fluid (WF) and a pump (22) arranged to pump the working fluid (WF) through the circuit (12), wherein the evaporator (14) is arranged for heat exchange between the working fluid (WF) and at least one heat source (24), wherein the waste heat recovery system (10) further comprises a cooling circuit (26) arranged in connection to the condenser (18), and wherein the expander (16) is mechanically connected to the powertrain (3). The method comprises the steps of: predicting (s101 ) a downhill slope and determining if the predicted downhill slope fulfils a predetermined requirement; determining (s102) the amount of energy that will be recovered by the waste heat recovery system (10) during the downhill slope; and controlling (s103) the vehicle (1 ) based on the determined amount of energy that will be recovered by the waste heat recovery system (10).The invention also relates to a vehicle (1), a computer program (Pr) and a computer program product.(Fig. 2)
    公开号:SE1651038A1
    申请号:SE1651038
    申请日:2016-07-12
    公开日:2018-01-13
    发明作者:Johansson Bjoern；Hoeckerdal Erik；Timren Thomas
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    A method for controlling a vehicle in connection with a downhill slopeand such a vehicle TECHNICAL FIELD The present invention relates to a method for controlling a vehicle in connectionwith a downhill slope, a vehicle, a computer program and a computer programproduct according to the appended claims.
    BACKGROUND Vehicie rrienutecturers ere todey striving te increese engine eftioiency andreduce tuei consumption. "i"his is speciticeiiy en issue tor rrienutecturers oi heevyvehicies, such es trucks end ouses. in vehioies ifvith oorrihustion engines sorneet the energy trorn the tuei is dissipeted es heet through the exheust pioes endthe engine eooiing systent. By the use ei e Weste heet recevery systern sorne otthe dissipeted heet niey instead he used te produce ntechenicei Work. "i"hentechenicei Work rney tor exenipie he trensierred to the ooWertrein end thus heused te prepei the vehicie. "i"his vvey the engine etticiency end the tuei consumption een tue irnoroved.
    Weste heet reeevery systems ere tyeieeiiy hesed en the Ftenkine cycie end thusceniprise e vverking iiuid, e ounip ter cireuieting the Working fiuid in e circuit, etieest ene evepereter. en exeensien device end ei ieest ene eendenser. "theWorking iiuid is suiteoiy in e iiquid stete to stert With. "the purnp pressurizes theWorking tiuid Which is purnped through the eveeoreter, "i"he Werking tiuid isheeted hy the heet sourceis) ieed through the eveeoreter end the Working tiuidihereey eveperetes. The veeour is suhseeueniiy expended in the expansiondevice. By rneens et the exoensien device the recevered heet is converted internechenieei vvork. The veeour is thereeiier coeied in the eendenser, such thetthe Working tiuid is brought oeck te its initiei iieuid stete. "the condenser is thus typicaiiy cenneeted te a eeeiing Circuit, Which eeeid he part et the engine ceeiingsystern er a separate eeeiing eircuit.
    The itieehanieai vverir generated hy the expansien device rnay iee transterred tethe pevvertrain et the vehieie it the expansien device is ineehanieaiiy eennectedte the petvertrain. Ûeeentent Liåâeüaët t253 At diseieses a vvaste heatrecevery systern where a shatt et a turhine (expansien device) is ceiipied te theengine crankshatt. "the rneehanieai werir; generated ey the expansien deviee isthus terdee used te prepei the vehieie. The extra tereee provided iey such Wasteheat recevery systerns ntay net aivvays ee desired. When a vehieie is drivingiiphiii high iead en the eernhestien engine vviii reseit in higher teihperattire et theexhaest gases and theretny rnere energy transterred via the evaeerater te thewaste heat recevery systern. This rneans that rnere tereee can he provided hythe expansien device. tfitriving uphiii, this is typicaiiy an advantage. iiewever,iivhen the vehieie starts driving devvnhiii the extra tergee previded ey the wasteheat recevery systern rnay net he desired ter preptiisien et the vehicie. in a iengdevvnhiii siepe the vehieie speed vviii increase dee te the mass et the vehicie(petentiai energy) and there is a risk that the vehicie speed eecenaes tee high.Depending en the iength et the devvnhiii siepe, extra teretie trern the vvaste heatrecevery systern rnay thus net he tisetui. Document DEEtGEGGSGttZtE Atdiseieses a vvaste heat recevery systern where the rnechanieai vverk trern theexpander is used te prepei a vehieie. When the vehieie is eraking er drivingdevvnhiii the centeiistien engine centinues te ren tntit the tiiei seppiy is steppedand the ieraking energy is stered thennaiiy.
    SUMMARY OF THE INVENTION Despite known solutions in the field, there is still a need to develop a method forcontrolling a vehicle in connection with a downhill slope, which enables energyoptimal operation of the vehicle.
    An object of the present invention is to achieve an advantageous method forcontrolling a vehicle in connection with a downhill slope, which reduces fuelconsumption and enables energy optimal operation of the vehicle.
    The herein mentioned objects are achieved by a method for controlling a vehicle,a vehicle, a computer program and a computer program product according tothe independent claims.
    According to an aspect of the present invention a method for controlling a vehiclein connection with a downhill slope is provided. The vehicle comprising apowertrain with a combustion engine, wherein the vehicle comprises a wasteheat recovery system associated with the combustion engine, the waste heatrecovery system comprising a working fluid circuit; an evaporator; an expander;a condenser; a reservoir for a working fluid and a pump arranged to pump theworking fluid through the circuit, wherein the evaporator is arranged for heatexchange between the working fluid and at least one heat source, wherein thewaste heat recovery system further comprises a cooling circuit arranged inconnection to the condenser, and wherein the expander is mechanicallyconnected to the powertrain. The method comprises the steps of: - predicting a downhill slope and determining if the predicted downhill slope fulfilsa predetermined requirement; - determining the amount of energy that will be recovered by the waste heatrecovery system during the predicted downhill slope; and - controlling the vehicle based on the determined amount of energy that will be recovered by the waste heat recovery system.
    The predetermined requirement is suitably that the gradient of the downhill slopeis such that braking of the vehicle will not be required. The predeterminedrequirement may be that the gradient of the downhill slope is such that brakingof the vehicle will not be required in order to maintain the vehicle speed below apredetermined vehicle speed (not exceed a predetermined vehicle speed) whiledriving down the predicted downhill slope.
    The method may comprise the steps of: - predicting a downhill slope which will not require braking of the vehicle; - determining the amount of energy that will be recovered by the waste heatrecovery system during the downhill slope; and - controlling the vehicle based on the determined amount of energy.
    The method may comprise the steps of: - predicting a downhill slope which will not require braking of the vehicle tomaintain the vehicle speed below a predetermined vehicle speed; - determining the amount of energy that will be recovered by the waste heatrecovery system during the predicted downhill slope; and - controlling the vehicle based on the determined amount of energy that will berecovered by the waste heat recovery system.
    The waste heat recovery system of the vehicle is sultably based on the Ftankinecycle, prefetably an organic Ftankine cycle. The working tiuid is thus sultahlyorganic, such as ethanoi or acetone. The waste heat recovery system based onthe Rankine cycle is sultably ccnfigured such that the Working fluld, suitabiy ln aliquid state, is purnped through the evaporator. The working fluid is therebyheated by the at least one heat source connected to the evaporator and thetyorking tluid thus evaporates. The vapout is then expanded ln the exoanderwhereby itiechanicai work is produced. The rnechanicai work is transferred frornthe expandet as totdue to the powettraln. The ntechanicai work inay for examplehe transferred to the orankshaft of the oornhustlon engine cr the geathox andthus be used to propei the vehicle. The vapour is thereatter cocied in thecondenser by heat exchange yyith the cooilng tluld in the cooilng clrcuit, suchthat the working tiuid is brought back to lts initial liquid state. The at least oneheat source in the vehicle cornprising the yvaste heat recovery system rnay heexhaust gases ironi the cornbustion engine, an exhaust gas recirculation system, the coeiing iiuid of the corrihustien engine, the cornhustion engine itseifer any ether hot cemhenent in the vehieie. The at ieast ene heat source ispreferahiy associated with the comhustien engine. The evaperator is suitahiy aheat exehanger connected te the at ieast ene heat source and the working fiuidcirouit. The heat transfer hetween the working fiuid and the heat source is enexchange oi energy resuiting in a change in temperature. Thes, the heat sourceis providing the energy entering the waste heat recovery systern and the energyis ieaving the vvaste heat recovery systern as rnechanicai work via the exeanderand as heat via the ceeiing eircuit. The temperature in the waste heat recoverysystern thus deeends en the amount ef energy entering the system and theamount ef energy ieaving the systern.
    The terdue provided hy the exeander heies ereeeiiing the vehicie hut there mighthe situatiens where the additionai tereue is net needed. in e iong dewnhiii siepethe vehicie speed wiii increase et itseif due to the mass ef the vehicie (eetentiaienergy). This often resuits in e need te hraite the vehicie somewhere aieng thedewnhiii sieoe in order net to exceed a predetermined vehieie speed. in order tesave fuei vehieies are usuaiiy eraited hy eeasting with a gear engaged whendriving dewn a iong stone. When the vehicie is coasting with a gear engaged,the engine is running and the ftiei stieeiy is cut off, such that the engine is drivenhy the driving wheeis et the vehicie. in such cases, the additienai tereueprovided hy the exeander et the waste heat recovery system is net needed erwanted. ifiiuring short dewnhiii sieoes however, the additienai tereue provided hythe exeander may he esefui. it is thereiere important to consider the energy thatcan he recovered hy the waste heat recovery system, and thus the rnechanicaiwork that can he provided hy the expander, when eianning the operation ef avehicie., iššy predicting a downhill slope and determining if the predicted downhillslope fulfils a predetermined requirement; determining the amount of energy thatwill be recovered by the waste heat recovery system during the downhill slope;and controlling the vehicle based on the determined amount of energy, thevehicle may be operated in an energy optimal way in connection with thepredicted downhill slope.
    The step of predicting a downhill slope which will not require braking of thevehicle suitably comprises to predict a downhill slope where the gradient is suchthat braking of the vehicle is not required in order to not exceed a predeterminedvehicle speed. Such predetermined vehicle speed may be a desired speedrequested by the operator of the vehicle, it may be a speed set by a controlsystem (e.g. a cruise control or a downhill speed control) or it may be a speedlimit. A downhill slope which will not require braking of the vehicle is typically ashort downhill slope. A downhill slope which will not require braking of the vehicleis typically a downhill slope where the change in potential energy is such thatthe predetermined vehicle speed can be maintained without braking the vehicle.A downhill slope which will not require braking of the vehicle is suitably predictedbased on road inclination, friction, length of the slope or similar. Such road datais available in the vehicle control system and may be determined according to conventional methods by means of navigation systems, sensors and/or cameras.
    Whether braking of the vehicle is necessary or not also depends on the vehiclecharacteristics, such as vehicle speed prior to the downhill slope and theweight/load of the vehicle. By predicting a downhill slope which will not requirebraking of the vehicle, a driving situation is predicted where mechanical workprovided by the waste heat recovery system may be useful.
    The step of determining the amount of energy that will be recovered by the wasteheat recovery system during the downhill slope suitably involves determining theadditional torque that the waste heat recovery system can provide during thedownhill slope. The torque provided by the waste heat recovery system ismechanical work converted from the recovered energy in the waste heatrecovery system and by determining the amount of energy recovered by thesystem the torque provided by the system is also determined. The method maycomprise the step of determining the amount of energy that will be recovered bythe waste heat recovery system during a predetermined period of time ahead.By determining the energy that can be recovered by the waste heat recoverysystem during the downhill slope the operation of the vehicle in connection with the downhill slope can be planned in an energy optimal way. The amount ofenergy that will be recovered by the waste heat recovery system during thedownhill slope is suitably determined based on estimated stored heat associatedwith the at least one heat source and a predicted mass flow of the at least oneheat source. The stored heat associated with the at least one heat source andthe mass flow will determine the amount of energy entering the waste heatrecovery system and thus the amount of energy that will be recovered by thewaste heat recovery system. The stored heat associated with the at least oneheat source will affect the temperature of the at least one heat source. Theamount of energy that will be recovered by the waste heat recovery systemduring the downhill slope is thus an estimate. The at least one heat source issuitably exhaust gases in an exhaust system of the vehicle and the energyrecovered by the waste heat recovery system is suitably determined based onthe estimated stored heat in the exhaust system upstream of the evaporator andthe predicted exhaust gas mass flow. The temperature of the exhaust gasesentering the evaporator thus depends on the stored heat in the exhaust systemupstream of the evaporator. The exhaust system may comprise an exhaust gasaftertreatment system which typically stores a lot of heat.
    The step of controlling the vehicle based on the determined amount of energythat will be recovered from the waste heat recovery system suitably comprisesto control the vehicle in connection to the predicted downhill slope based on thedetermined amount of energy. The step of controlling the vehicle may compriseto control the vehicle speed based on the amount of energy that can berecovered in the system. Vehicles today typically comprise various cruise controlsystems for controlling the speed of the vehicle. Different aspects, such as fuelconsumption, comfort and time are considered when controlling the vehicle anddifferent systems use different strategies for controlling the vehicle. When thevehicle comprises a waste heat recovery system which provides mechanicalwork to the powertrain, it is therefore important that these systems also considerthe waste heat recovery system when planning the operation of the vehicle. This way, the vehicle can be operated with optimal energy utilization.
    According to an aspect of the invention the step of controlling the vehicle speedcomprises to decrease the vehicle speed prior to the downhi| slope, wherein thedecrease depends on the determined amount of energy that can be recoveredby the waste heat recovery system during the downhi| slope. One strategy ofoperating a vehicle in a short downhi| slope is to keep the combustion engineconnected to the powertrain with a gear engaged and the fuel supply cut off,such that the combustion engine is driven by the driving wheels of the vehicle.This strategy improves the fuel consumption and braking of the vehicle isavoided. With a waste heat recovery system according to the invention,additional torque will be provided to the powertrain. This additional torque mustbe considered when controlling the vehicle speed if braking of the vehicle is tobe avoided. Since the expander of the waste heat recovery system is connectedto the powertrain the additional torque will act on the driving wheels and therebyhelp propelling the vehicle. By decreasing the vehicle speed prior to the downhi|slope braking of the vehicle can be avoided despite the additional torqueprovided by the waste heat recovery system. The vehicle speed at the crest ofthe downhi| slope is suitably decreased. The decrease depends on thedetermined amount of energy that will be recovered by the waste heat recoverysystem during the downhi| slope. The more energy that will be recovered by the waste heat recovery system the more additional torque will act on the powertrain.
    Thus, the more energy that will be recovered by the waste heat recovery systemthe more should the vehicle speed be decreased prior to the downhi| slope.
    According to an aspect of the invention the step of controlling the vehiclecomprises to, when driving down the slope, disconnect the combustion enginefrom the rest of the powertrain and ensure that the combustion engine isoperated with an engine speed which does not exceed a standard idling speedby means of the energy recovered by the waste heat recovery system. The stepof controlling the vehicle suitably comprises to, when driving down the slope,disconnect the combustion engine from the rest of the powertrain and ensurethat the combustion engine is operated with a standard idling speed at least partly by means of the energy recovered by the waste heat recovery system.One strategy of operating a vehicle in a short downhill slope is to disconnect thecombustion engine from the rest of the powertrain and control the combustionengine to a standard id|ing speed. With a waste heat recovery system accordingto the invention, additional torque will be provided to the powertrain. Thisadditional torque must be considered when controlling the engine speed. Theexpander of the waste heat recovery system is suitably connected to thecombustion engine, such that the additional torque will act on the crankshaft ofthe combustion engine. This way, the additional torque will help the combustionengine maintaining the id|ing speed. By operating the vehicle with thecombustion engine id|ing during the downhill slope, the waste heat recoverysystem will add energy to the combustion engine and less fuel is needed toachieve the id|ing speed of the combustion engine. The fuel injection to thecombustion engine can be controlled so that the energy provided by the injectedfuel, together with the energy from the waste heat recovery system, results in astandard id|ing speed of the combustion engine. By disconnecting thecombustion engine from the rest of the powertrain and ensuring that thecombustion engine is operated with a standard id|ing speed at least by meansof the energy recovered from the waste heat recovery system, the fuelconsumption is reduced and the vehicle is operated in an energy optimal way.
    The step of controlling the vehicle may alternatively comprise to, when drivingdown the slope, disconnect the combustion engine from the rest of thepowertrain, control the combustion engine to an engine speed lower than thestandard id|ing speed and ensure that the waste heat recovery system providesadditional torque to the powertrain. Since the id|ing speed of the combustionengine is achieved partly by means of the torque provided by the waste heatrecovery system, the engine speed of the combustion engine can be decreasedto a speed lower than the standard id|ing speed. Normally, a too low id|ing speedof a combustion engine will result in vibrations caused by excited resonantfrequencies from the combustion engine. Such vibrations affect the comfort inthe vehicle and should be avoided. However, the waste heat recovery system according to the invention is vibration-free and since the waste heat recoverysystem provides torque to the combustion engine, less torque is needed fromcombustion in the combustion engine for achieving the engine speed. Theexcitation amplitude from the combustion engine is thereby decreased and theengine speed can be decreased below the standard id|ing speed withmaintained comfort. This way, the fuel consumption is decreased further.
    According to an aspect of the invention the step of contro|ing the vehiclecomprises to, when driving down the slope, turn off the combustion engine andcontrol the working fluid in the waste heat recovery system to bypass theexpander. One strategy of operating a vehicle in a short downhill slope is to turnof the combustion engine. Normally when the combustion engine is turned off,the waste heat recovery system is turned off since the at least one heat sourceis associated with the combustion engine. However, if the combustion engine isturned off in a short downhill slope where braking of the vehicle is not required,there is no need to turn off the waste heat recovery system. lnstead the wasteheat recovery system is kept active but the torque provided by the expander willnot be needed since the combustion engine is turned off. The torque providedby the waste heat recovery system is not enough to alone rotate the crankshaftof the combustion engine. By contro|ing the working fluid in the waste heatrecovery system such that it is bypassed the expander, no mechanical work isgenerated by the expander. The waste heat recovery system is thus kept activein a safe state with low risk of overheating or damaging the system, while storingthe available heat/energy for later utilization. This way, the waste heat recovery is ready to produce useful work directly when it is needed again.
    The method steps are suitably performed by means of a control unit connectedto the waste heat recovery system. The predetermined vehicle speed is suitably stored in the control unit.
    According to an aspect of the present invention a vehicle comprising apowertrain with a combustion engine is provided. The vehicle further comprises 11 a waste heat recovery system associated with the combustion engine, the wasteheat recovery system comprising a working fluid circuit; an evaporator; anexpander; a condenser; a reservoir for a working fluid and a pump arranged topump the working fluid through the circuit, wherein the evaporator is arrangedfor heat exchange between the working fluid and at least one heat source, andwherein the waste heat recovery system further comprises a coo|ing circuitarranged in connection to the condenser, and wherein the expander ismechanically connected to the powertrain. The vehicle further comprises acontrol unit adapted to predict a downhill slope and determine if the predicteddownhill slope fulfils a predetermined requirement; determine the amount ofenergy that will be recovered by the waste heat recovery system during thedownhill slope; and to control the vehicle based on the determined amount ofenergy. By predicting a downhill slope and determine if it fulfils a predeterminedrequirement; determining the amount of energy that will be recovered by thewaste heat recovery system during the downhill slope; and controlling thevehicle based on the determined amount of energy, the vehicle may be operated in an energy optimal way in connection with the predicted downhill slope.
    The predetermined requirement is suitably that the gradient of the downhill slopeis such that braking of the vehicle will not be required. The predeterminedrequirement may be that the gradient of the downhill slope is such that brakingof the vehicle will not be required in order to maintain the vehicle speed below apredetermined vehicle speed (not exceed a predetermined vehicle speed) whiledriving down the predicted downhill slope. The control unit may be adapted topredict a downhill slope which will not require braking of the vehicle; determinethe amount of energy that will be recovered by the waste heat recovery systemduring the downhill slope; and control the vehicle based on the determinedamount of energy. The control unit may be adapted to predict a downhill slopewhich will not require braking of the vehicle to maintain the vehicle speed belowa predetermined vehicle speed; determine the amount of energy that will berecovered by the waste heat recovery system during the predicted downhillslope; and control the vehicle based on the determined amount of energy that 12 will be recovered by the waste heat recovery system. The predetermined vehiclespeed may be a desired speed requested by the operator of the vehicle, it maybe a speed set by a control system or it may be a speed limit. The control unit issuitably adapted to predict a downhill slope which will not require braking of thevehicle based on road inclination, friction, length of the slope or similar. Suchroad data is available for the control unit and may be determined according toconventional methods by means of navigation systems, sensors and/or camerasarranged on the vehicle. The control unit may be adapted to predict a downhillslope which will not require braking of the vehicle based on vehiclecharacteristics, such as vehicle speed and the weight/load of the vehicle.
    The control unit is suitably connected to the components of the waste heat recovery system such as the evaporator, the expander, the condenser and thepump.
    The control unit may be adapted to determine the additional torque that thewaste heat recovery system will provide during the downhill slope. The torqueprovided by the waste heat recovery system is mechanical work converted fromthe recovered energy in the waste heat recovery system and by determining theamount of energy recovered by the system the torque provided by the system isalso determined.
    According to an aspect of the invention the control unit is adapted to determinethe amount of energy that will be recovered by the waste heat recovery systembased on estimated stored heat associated with the at least one heat sourceand a predicted mass flow of the at least one heat source. The stored heatassociated with the at least one heat source will affect the temperature of the atleast one heat source. The stored heat associated with the at least one heatsource and the mass flow will thus determine the amount of energy entering the waste heat recovery system and thus the amount of energy that will be 13 recovered by the waste heat recovery system. The control unit is thus adaptedto estimate the amount of energy that will be recovered by the waste heatrecovery system during the downhi| slope. The at least one heat source issuitably exhaust gases in an exhaust system and the control unit is thus suitablyadapted to determine the amount of energy that will be recovered by the wasteheat recovery system based on estimated stored heat in the exhaust systemupstream of the evaporator and the predicted exhaust gas mass flow. Theexhaust system of the vehicle may comprise exhaust pipes and conduits leadingthe exhaust gases from the combustion engine via an exhaust gasaftertreatment system and the waste heat recovery system to the environment.
    The control unit is suitably adapted to control the vehicle speed based on theamount of energy that can be recovered from the system. The vehicle suitablycomprises various cruise control systems for controlling the vehicle speed.Different aspects, such as fuel consumption, comfort and time are consideredwhen controlling the vehicle and different systems use different strategies forcontrolling the vehicle. When the vehicle comprises a waste heat recoverysystem which provides mechanical work to the powertrain, it is thereforeimportant that the waste heat recovery system is considered when planning theoperation of the vehicle. This way, the vehicle can be operated with optimal energy utilization.
    According to an aspect of the invention the control unit is adapted to decreasethe vehicle speed prior to the predicted downhi| slope, wherein the decreasedepends on the determined amount of energy that can be recovered from thewaste heat recovery system during the downhi| slope. The control unit is suitablyadapted to decrease the vehicle speed at the crest of the predicted downhi|slope. The control unit may be adapted to ensure that the combustion engine isconnected to the rest of the powertrain, ensure that a gear is engaged and cutoff the fuel supply. This way, the combustion engine is driven by the drivingwheels of the vehicle. Since the expander of the waste heat recovery system is connected to the powertrain of the vehicle the additional torque provided by the 14 expander will act on the driving wheels and thereby help propelling the vehicle.By decreasing the vehicle speed prior to the downhill slope braking of the vehiclecan be avoided despite the additional torque provided by the waste heat recovery system.
    According to an aspect of the invention the control unit is adapted to, when thevehicle is driving down the slope, disconnect the combustion engine from therest of the powertrain and ensure that the combustion engine is operated withan engine speed not exceeding a standard idling speed by means of the energyrecovered by the waste heat recovery system. The control unit is suitablyadapted to, when the vehicle is driving down the slope, disconnect thecombustion engine from the rest of the powertrain and ensure that thecombustion engine is operated with a standard idling speed by means of at leastpartly, the energy recovered by the waste heat recovery system. With a vehiclecomprising a waste heat recovery system according to the invention, additionaltorque will be provided to the powertrain when the waste heat recovery systemis active. Additional torque means torque in addition to the torque provided bycombustion in the combustion engine. This additional torque must be consideredwhen controlling the vehicle speed. The expander of the waste heat recoverysystem is suitably connected to the combustion engine, such that the additionaltorque will act on the crankshaft of the combustion engine. This way, theadditional torque will help maintaining the idling speed of the combustion engine.By disconnecting the combustion engine from the rest of the powertrain andensuring that the combustion engine is operated with a standard idling speed bymeans of the energy recovered from the waste heat recovery system, the fuelconsumption is reduced and the vehicle is operated in an energy optimal way.
    According to an aspect of the invention the control unit is adapted to, when thevehicle is driving down the slope, disconnect the combustion engine from therest of the powertrain, control the combustion engine to an engine speed lowerthan the standard idling speed and ensure that the waste heat recovery systemprovides additional torque to the powertrain. Since the control unit is adapted to ensure that torque is provided by the waste heat recovery system, the enginespeed of the combustion engine can be decreased to a speed lower than thestandard idling speed. Normally, a too low idling speed of a combustion enginewill result in vibrations caused by excited resonant frequencies from thecombustion engine. However, since the waste heat recovery system providestorque to the combustion engine, less torque is needed from combustion in thecombustion engine for achieving the engine speed. The excitation amplitudefrom the combustion engine is thereby decreased and the engine speed can be decreased below the standard idling speed with maintained comfort.
    According to an aspect of the invention the control unit is adapted to turn off thecombustion engine and control the working fluid in the waste heat recovery system to bypass the expander, when the vehicle is driving down the slope.
    The cooling circuit connected to the condenser may be part of the combustionengine cooling system or a separate cooling system. The cooling fluid coolingthe condenser may thereby be circulated in the cooling circuit by a cooling pump,driven by the combustion engine or by an electric machine.
    The waste heat recovery system may comprise one or more evaporators/ heatexchangers. The waste heat recovery system may for example comprise arecuperator arranged to pre-heat the working fluid before entering theevaporator. The waste heat recovery system may also comprise one or morecondensers, such that cooling of the working fluid may be performed in multiplesteps. Furthermore, the system may comprise one or more expanders. Theexpander is suitably a fixed displacement expander, or turbine. The expandermay be mechanically connected directly to the combustion engine or it may bemechanically connected to the gearbox or other components of the powertrain.
    The vehicle may be a hybrid vehicle. Such hybrid vehicle comprises an electricmachine for propulsion, in addition to the combustion engine. The control unitmay be the engine control unit or may comprise a plurality of different control 16 units. The control unit may be a part of a cruise control system or a vehiclecontrol system. A computer may be connected to the control unit.
    Further objects, advantages and novel features of the present invention willbecome apparent to one skilled in the art from the following details, and also byputting the invention into practice. Whereas the invention is described below, itshould be noted that it is not restricted to the specific details described.Specialists having access to the teachings herein will recognise furtherapplications, modifications and incorporations within other fields, which arewithin the scope of the invention.
    BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and further objects andadvantages of it, the detailed description set out below should be read togetherwith the accompanying drawings, in which the same reference notations denote similar items in the various drawings, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment ofthe invention; Figure 2 schematically illustrates a waste heat recovery system accordingto an embodiment of the invention; Figure 3 schematically illustrates a flow chart for a method for controlling avehicle according to an embodiment of the invention; and Figure 4 schematically illustrates a control unit or computer according to an embodiment of the invention.
    DETAILED DESCRIPTION OF THE DRAWINGS 17 Figure 'i seherriatieaiiy shows a side view of a vehicie i according to anernhodirnent of the invention. The vehicie i has a powertrain 3 cornprising acorriioustion engine 2 and a gearbox 4 connected to the contbustion engine 2and the driving wheeis 6 ot the vehicie i. The vehicie t further cornprises awaste heat recovery system til) associated with the powertrain 3. The vehicle 1may be a heavy vehicle, e.g. a truck or a bus. The vehicle 1 may alternativelybe a passenger car. The vehicle may be a hybrid vehicle comprising an electricmachine (not shown) in addition to the combustion engine 2. The waste heat recovery system 10 in the vehicle 1 will be further described in Figure 2.
    Figure 2 schenfiaticaiiy shows a waste heat recovery system 10 associated witha powertrain 3 of the vehicle 1 according to an embodiment of the invention. Thevehicle 1 is suitably configured as described in Figure 1. The waste heatrecovery system 10 comprises a working fluid circuit 12; an evaporator 14; anexpander 16; a condenser 18; a reservoir 20 for a working fluid WF and a pump22 arranged to pump the working fluid WF through the circuit 12, wherein theevaporator 14 is arranged for heat exchange between the working fluid WF andat least one heat source 24, wherein the waste heat recovery system 10 furthercomprises a cooling circuit 26 arranged in connection to the condenser 18 andwherein the expander 16 is mechanically connected to the powertrain 3.
    The waste heat recovery system 10 is suitahiy based on an organic Ftankinecycie. The working iiuid WF is thus suitabiy organic, such as ethanoi or acetone.The vvaste heat recovery system ti) is configured such that the iiduid tvorkingfiuid WF is purnped ironi ipw pressure to high pressure and enters theevaporator 14. The working fiuid WF is titerehy heated hy the at ieast one heatsource 24 connected to the evaporator ta and the working fiuid WF is thusevaporated, The vapour is then expanded in the expander 16 wherebyrnechanicai tfvork is produced and transterred to the powertrain 3, wherepy thetemperature and the pressure of the vapour is decreased. The vapour thereafterenters the condenser 18 vvhere condensation through heat exchange betweenthe vapour and the cooiing fiuid of the cooiing circuit 26 brings the working fiuid 18 WP hack to its initiai iiotiid state. Thtis, the heat source 24 is providing the energyentering the waste heat recovery system 10 and the energy is ieaving the wasteheat recovery system ti) as mechanicai work via the expander 16 and as heatvia the cooiing circuit 26 cooiihg the condenser tå., The vehicle 1 comprises a control unit 30 arranged in communication with thewaste heat recovery system 10. The control unit 30 is adapted to predict adownhill slope which will not require braking of the vehicle 1; determine theamount of energy that will be recovered by the waste heat recovery system 10during the downhill slope; and to control the vehicle 1 based on the determinedamount of energy that will be recovered by the waste heat recovery system 10.A computer 32 may be connected to the control unit 30.
    Only vapour should enter the expander 16 and the waste heat recovery system10 therefore comprises a bypass arrangement 34, such that the working fluidWF can be controlled to bypass the expander 16 through the bypassarrangement 34. The control unit 30 may be adapted to control the bypassarrangement 34 such that the working fluid WF is bypassing the expander 16.
    The expander 16 is suitably a fixed displacement expander, such as a pistonexpander, or a turbine. The expander 16 may be mechanically connecteddirectly to the combustion engine 2 or to the gearbox 4. The at ieast one heatsource 24 connected to the evaporator 14 rnay be exhaust gases from thecombustion engine 2, an exhatist gas recirctiiation system (EGR), the cooiingfiuid of the combustion engine 2, the cornhtistioh engine 2 itseif or any other hotcomponent: associated with the combustion engine 2. The at ieast one heatsource 24 is herein iiitistrated as a medium passing through the evaporator t-fi.The ai; ieast one heat source 24 is hereiri iiiostratted as arrows and may heexhatist gases originating from the combustion engine 2. The at ieast one heatsource 24 is soitabiy part of an exhaost system 36 oi the vehicie t. The exhaostsystern 36 is here iiitistrated as exhaust pipes/dticts bot may aiso cornprise anexhaust gas aftertreatrnent system (not shown), an exhatist gas recirctiiation 19 system etc. The waste heat reeevery system ti) may eemerise a eiuraiity ef heatseurees 24. The evaporator 14 is suitabiy a heat exchanger eehnected te the atieast ene heat source 24 and the werking fiuid czireuit 12. The waste heatrecovery system 10 may comprise one or more heat exchangers 14. The wasteheat recovery system 10 may for example comprise a recuperator arranged topre-heat the working fluid before entering the evaporator 14. The waste heatrecovery system 10 may also comprise one or more condensers 18, such thatcooling down of the working fluid WF may be performed in multiple steps.
    Furthermore, the system 10 may comprise one or more expanders 16.
    The pump 22 pressurizing and cireuiating the werking fiuid WF through theeireuit 12 may be damaged if the working fiuid WF entering the pump 22 is netin a Eiguid state. Thus in the case where the temperature dewnstream ef theeendenser 18 is tee high, such that the working iiuid WF is net in a iiquid state,the pressure in the reservoir 20 may be increased. This way, the working ttuidWF is breught te a iiquid state and may be pumped by the pump 22. The pump 22 is suitapiy eieetrieaiiy driven.
    The cooling circuit 26 connected to the condenser 18 may be part of thecombustion engine cooling system or a separate cooling system. The cooling fluid in the cooling circuit 26 may thereby be pumped by a cooling pump (not shown) driven by the combustion engine 2 or by an electric machine (not shown).
    Figure 3 shows a flowchart for a method for controlling a vehicle 1 in connectionwith a downhill slope. The vehicle 1 is configured as described in Figure 1 and2. The vehicle 1 comprises a powertrain 3 with a combustion engine 2 and awaste heat recovery system 10 associated with the combustion engine 2, thewaste heat recovery system 10 comprising a working fluid circuit 12; anevaporator 14; an expander 16; a condenser 18; a reservoir 20 for a workingfluid WF and a pump 22 arranged to pump the working fluid WF through thecircuit 12, wherein the evaporator 14 is arranged for heat exchange between theworking fluid WF and at least one heat source 24, wherein the waste heat recovery system 10 further comprises a cooling circuit 26 arranged in connectionto the condenser 18, and wherein the expander 16 is mechanically connectedto the powertrain 3. The method comprises the steps of predicting s101 adownhi| slope and determining if the predicted downhi| slope fulfils apredetermined requirement; determining s102 the amount of energy that will berecovered by the waste heat recovery system 10 during the downhi| slope; andcontrolling the vehicle 1 based on the determined amount of energy.
    The predetermined requirement is suitably that the gradient of the downhi| slopeis such that braking of the vehicle 1 will not be required in order to maintain thevehicle speed below a predetermined vehicle speed (not exceed apredetermined vehicle speed) while driving down the predicted downhi| slope.The predetermined vehicle speed may be a desired speed requested by theoperator of the vehicle, it may be a speed set by a control system or it may be a speed limit.
    The step of predicting s101 a downhi| slope suitably comprises to predict adownhi| slope which will not require braking of the vehicle 1. The step ofpredicting s101 a downhi| slope suitably comprises to predict a downhi| slopewhich will not require braking of the vehicle 1 to maintain the vehicle speed below a predetermined vehicle speed.
    The step of predicting s101 a downhi| slope suitably comprises to predict adownhi| slope where the gradient is such that braking of the vehicle 1 is notSuchpredetermined vehicle speed may be a desired speed requested by the operator required in order to not exceed a predetermined vehicle speed. of the vehicle, it may be a speed set by a control system or it may be a speed limit.
    A downhi| slope which will not require braking of the vehicle 1 may be predictedbased on road inclination, friction, length of the slope or similar. Such road datais available in the vehicle 1 and may be determined according to conventional 21 methods by means of navigation systems, sensors and/or cameras arranged inthe vehicle 1. The step of predicting s101 a downhill slope which will not requirebraking of the vehicle 1 may further be based on vehicle characteristics, suchas vehicle speed and the weight/load of the vehicle 1.
    The step of determining s102 the amount of energy that will be recovered by thewaste heat recovery system 10 during the downhill slope suitably involvesdetermining the additional torque that the waste heat recovery system 10 willprovide during the downhill slope. The method may comprise the step ofdetermining the amount of energy that will be recovered by the waste heatrecovery system 10 during a predetermined period of time ahead. Bydetermining the energy that can be recovered by the waste heat recoverysystem 10 during the downhill slope the operation of the vehicle in connectionwith the downhill slope can be planned in an energy optimal way.
    The amount of energy that will be recovered by the waste heat recovery system10 during the downhill slope is suitably determined based on estimated storedheat associated with the at least one heat source 24 and a predicted mass flowof the at least one heat source 24. The stored heat associated with the at leastone heat source 24 and the mass flow will determine the amount of energyentering the waste heat recovery system 10 and thus the amount of energy thatwill be recovered by the waste heat recovery system 10. The stored heatassociated with the at least one heat source 24 will affect the temperature of theat least one heat source 24. The at least one heat source 24 is suitably exhaustgases in an exhaust system 36 of the vehicle 1 and the energy recovered by thewaste heat recovery system 10 is suitably determined based on the estimatedstored heat in the exhaust system 36 upstream of the evaporator 14 and thepredicted exhaust gas mass flow. The temperature of the exhaust gases 24entering the evaporator 14 thus depends on the stored heat in the exhaustsystem 36 upstream of the evaporator 14. The exhaust system 36 may comprisean exhaust gas aftertreatment system which typically stores a lot of heat. 22 The step of controlling s103 the vehicle 1 based on the determined amount ofenergy that will be recovered by the waste heat recovery system 10 suitablycomprises to control the vehicle 1 in connection to the predicted downhill slopebased on the determined amount of energy. The step of controlling s103 thevehicle 1 may comprise to control the vehicle speed based on the amount ofenergy that can be recovered by the waste heat recovery system 10.
    The step of controlling s103 the vehicle speed may comprise to decrease thevehicle speed prior to the downhill slope, wherein the decrease depends on thedetermined amount of energy that can be recovered by the waste heat recoverysystem 10 during the downhill slope. One strategy of operating a vehicle 1 in ashort downhill slope is to keep the combustion engine 2 connected to thepowertrain 3 with a gear engaged and the fuel supply cut off, such that thecombustion engine 2 is driven by the driving wheels 6 of the vehicle 1. Thisstrategy improves the fuel consumption and braking of the vehicle 1 is avoided.With a waste heat recovery system 10 according to the invention, additionaltorque will be provided to the powertrain 3. This additional torque must beconsidered when controlling the vehicle speed if braking of the vehicle 1 is to beavoided. Since the expander 16 of the waste heat recovery system 10 isconnected to the powertrain 3 the additional torque will act on the driving wheels6 and thereby help propelling the vehicle 1. By decreasing the vehicle speedprior to the downhill slope braking of the vehicle 1 can be avoided despite theadditional torque provided by the waste heat recovery system 10. The decreasedepends on the determined amount of energy that will be recovered by the wasteheat recovery system 10 during the downhill slope. The more energy that will berecovered by the waste heat recovery system 10 the more should the vehiclespeed be decreased prior to the downhill slope.
    The step of controlling s103 the vehicle 1 may comprise to, when driving downthe slope, disconnect the combustion engine 2 from the rest of the powertrain 3and ensure that the combustion engine 2 is operated with an engine speedwhich does not exceed a standard idling speed by means of the energy 23 recovered by the waste heat recovery system 10. The step of controlling s103the vehicle 1 may comprise to, when driving down the slope, disconnect thecombustion engine 2 from the rest of the powertrain 3 and ensure that thecombustion engine 2 is operated with a standard idling speed by means of theenergy recovered by the waste heat recovery system 10. One strategy ofoperating a vehicle 1 in a short downhi| slope is to disconnect the combustionengine 2 from the rest of the powertrain 3 and control the combustion engine 2to a standard idling speed. With a waste heat recovery system 10 according tothe invention, additional torque will be provided to the powertrain 3. Theexpander 16 of the waste heat recovery system 10 is suitably connected to thecombustion engine 2, such that the additional torque will act on the crankshaftof the combustion engine 2. This way, the additional torque will help thecombustion engine 2 maintaining the idling speed. By operating the vehicle 1with the combustion engine 2 idling during the downhi| slope, the waste heatrecovery system 10 will add energy to the combustion engine 2 and less fuel isneeded to achieve the idling speed of the combustion engine 2. Bydisconnecting the combustion engine 2 from the rest of the powertrain 3 andensuring that the combustion engine 2 is operated with a standard idling speedby means of the energy recovered from the waste heat recovery system 10, thefuel consumption is reduced and the vehicle 1 is operated in an energy optimal way.
    The step of controlling s103 the vehicle 1 may comprise to, when driving downthe slope, disconnect the combustion engine 2 from the rest of the powertrain 3,control the combustion engine 2 to an engine speed lower than the standardidling speed and ensure that the waste heat recovery system 10 providesadditional torque to the powertrain 3. Since torque is provided by the waste heatrecovery system 10, less torque is needed from combustion and the enginespeed of the combustion engine 2 can be decreased to a speed lower than thestandard idling speed. Normally, a too low idling speed of a combustion engine2 will result in vibrations caused by excited resonant frequencies from thecombustion engine 2. However, since the waste heat recovery system 10 24 provides torque to the combustion engine 2, less torque is needed fromcombustion in the combustion engine 2 for achieving the engine speed. Theexcitation amplitude from the combustion engine 2 is thereby decreased and theengine speed can be decreased below the standard id|ing speed with maintained comfort. This way, the fuel consumption is decreased further.
    The step of controlling s103 the vehicle 1 may comprise to, when driving downthe slope, turn off the combustion engine 2 and control the working fluid WF inthe waste heat recovery system 10 to bypass the expander 16. The workingfluid WF is suitably controlled to bypass the expander 16 via the bypassarrangement 34. One strategy of operating a vehicle 1 in a short downhill slopeis to turn of the combustion engine 2. Normally when the combustion engine 2is turned off, the waste heat recovery system 10 is turned off since the at leastone heat source 24 is associated with the combustion engine 2. However, if thecombustion engine 2 is turned off in a short downhill slope where braking of thevehicle 1 is not required, there is no need to turn off the waste heat recoverysystem 10. lnstead the waste heat recovery system 10 is kept active but thetorque provided by the expander 16 will not be needed since the combustionengine 2 is turned off. By controlling the working fluid WF in the waste heatrecovery system 10 such that it is bypassed the expander 16, no mechanical work is generated by the expander 16.
    The method steps are suitably performed by means of a control unit 30connected to the waste heat recovery system 10. The predetermined vehicle speed is suitably stored in the control unit 30.
    Figure 4 schematically illustrates a device 500. The control unit 30 and/orcomputer 32 described with reference to Figure 2 may in a version comprise thedevice 500. The term “link” refers herein to a communication link which may bea physical connection such as an optoelectronic communication line, or a non-physical connection such as a wireless connection, e.g. a radio link ormicrowave link. The device 500 comprises a non-volatile memory 520, a data processing unit 510 and a read/write memory 550. The non-volatile memory 520has a first memory element 530 in which a computer program, e.g. an operatingsystem, is stored for controlling the function of the device 500. The device 500further comprises a bus controller, a serial communication port, I/O means, anA/D converter, a time and date input and transfer unit, an event counter and aninterruption controller (not depicted). The non-volatile memory 520 has also asecond memory element 540.
    There is provided a computer program P which comprises routines for a methodfor controlling a waste heat recovery system 10 associated with a combustionengine 2 of a vehicle 1 according to the invention. The computer program Pcomprises routines for predicting a downhill slope and determining if thepredicted downhill slope fulfils a predetermined requirement. The computerprogram P comprises routines for predicting a downhill slope which will notrequire braking of the vehicle. The computer program P comprises routines fordetermining the amount of energy that will be recovered from the waste heatrecovery system during the downhill slope. The computer program P comprisesroutines for controlling the vehicle based on the determined amount of energythat will be recovered from the waste heat recovery system. The computerprogram P comprises routines for controlling the vehicle speed based on theamount of energy that can be recovered by the waste heat recovery system.The computer program P comprises routines for decreasing the vehicle speedprior to the downhill slope, wherein the decrease depends on the determinedamount of energy that can be recovered from the waste heat recovery systemduring the downhill slope. The computer program P comprises routines fordisconnecting the combustion engine from the rest of the powertrain andensuring that the combustion engine is operated with a standard idling speed bymeans of the energy recovered from the waste heat recovery system. Thecomputer program P comprises routines for controlling the combustion engineto an engine speed lower than the standard idling speed. The computer programP comprises routines for turning off the combustion engine and controlling theworking fluid in the waste heat recovery system to bypass the expander. The 26 program P may be stored in an executable form or in a compressed form in a memory 560 and/or in a read/write memory 550.
    Where the data processing unit 510 is described as performing a certain function,it means that the data processing unit 510 effects a certain part of the programstored in the memory 560 or a certain part of the program stored in the read/writememory 550.
    The data processing device 510 can communicate with a data port 599 via adata bus 515. The non-volatile memory 520 is intended for communication withthe data processing unit 510 via a data bus 512. The separate memory 560 isintended to communicate with the data processing unit 510 via a data bus 511.The read/write memory 550 is adapted to communicating with the dataprocessing unit 510 via a data bus 514.
    When data are received on the data port 599, they are stored temporarily in thesecond memory element 540. When input data received have been temporarilystored, the data processing unit 510 is prepared to effect code execution asdescribed above.
    Parts of the methods herein described may be effected by the device 500 bymeans of the data processing unit 510 which runs the program stored in thememory 560 or the read/write memory 550. When the device 500 runs theprogram, methods herein described are executed.
    The foregoing description of the preferred embodiments of the present inventionis provided for i|ustrative and descriptive purposes. lt is not intended to beexhaustive or to restrict the invention to the variants described. l/lanymodifications and variations will obviously be apparent to one ski|ed in the art.The embodiments have been chosen and described in order best to explain theprinciples of the invention and its practical applications and hence make it 27 possible for specialists to understand the invention for various embodiments andwith the various modifications appropriate to the intended use.
    权利要求:
    Claims (16)
    [1] 1. A method for controlling a vehicle (1) in connection with a downhill slope, thevehicle (1) comprising a powertrain (3) with a combustion engine (2); and awaste heat recovery system (10) associated with the combustion engine (2), thewaste heat recovery system (10) comprising a working fluid circuit (12); anevaporator (14); an expander (16); a condenser (18); a reservoir (20) for aworking fluid (WF) and a pump (22) arranged to pump the working fluid (WF)through the circuit (12), wherein the evaporator (14) is arranged for heatexchange between the working fluid (WF) and at least one heat source (24),wherein the waste heat recovery system (10) further comprises a cooling circuit(26) arranged in connection to the condenser (18), and wherein the expander(16) is mechanically connected to the powertrain (3), characterized by thesteps of: - predicting (s101) a downhill slope and determining if the predicted downhillslope fulfils a predetermined requirement; - determining (s102) the amount of energy that will be recovered by the wasteheat recovery system (10) during the downhill slope; and - controlling (s103) the vehicle (1) based on the determined amount of energythat will be recovered by the waste heat recovery system (10).
    [2] 2. The method according to claim 1, wherein the predetermined requirement isthat the gradient of the downhill slope is such that braking of the vehicle 1 willnot be required.
    [3] 3. The method according to claim 1 or 2, wherein the amount of energy that willbe recovered by the waste heat recovery system (10) is determined based onestimated stored heat associated with the at least one heat source (24) and apredicted mass flow of the at least one heat source (24).
    [4] 4. The method according to any of claims 1-3, wherein the step of controlling(s103) the vehicle comprises to control the vehicle speed based on the amountof energy that can be recovered by the system (10). 29
    [5] 5. The method according to claim 4, wherein the step of controlling (s103) thevehicle speed comprises to decrease the vehicle speed prior to the downhillslope, wherein the decrease depends on the determined amount of energy thatwill be recovered by the waste heat recovery system (10) during the downhill s|ope _
    [6] 6. The method according to any of claims 1-3, wherein the step of controlling(s103) the vehicle (1) comprises to, when driving down the slope, disconnect thecombustion engine (2) from the rest of the powertrain (3) and ensure that thecombustion engine (2) is operated with an engine speed which does not exceeda standard idling speed by means of the energy recovered by the waste heat recovery system (10).
    [7] 7. The method according to any of claims 1-3, wherein the step of controlling(s103) the vehicle (1) comprises to, when driving down the slope, turn off thecombustion engine (2) and control the working fluid (WF) in the waste heat recovery system (10) to bypass the expander (16).
    [8] 8. A vehicle (1), comprising a powertrain (3) with a combustion engine (2); anda waste heat recovery system (10) associated with the combustion engine (2),the waste heat recovery system (10) comprising a working fluid circuit (12); anevaporator (14); an expander (16); a condenser (18); a reservoir (20) for aworking fluid (WF) and a pump (22) arranged to pump the working fluid (WF)through the circuit (12), wherein the evaporator (14) is arranged for heatexchange between the working fluid (WF) and at least one heat source (24), andwherein the waste heat recovery system (10) further comprises a cooling circuit(26) arranged in connection to the condenser (18), and wherein the expander(16) is mechanically connected to the powertrain (3), characterized in that thevehicle (1) comprises a control unit (30) adapted to predict a downhill s|ope and determine if the predicted downhill s|ope fulfils a predetermined requirement; determine the amount of energy that will be recovered by the waste heatrecovery system (10) during the downhill slope; and to control the vehicle based on the determined amount of energy.
    [9] 9. The vehicle according to claim 8, wherein the predetermined requirement isthat the gradient of the downhill slope is such that braking of the vehicle 1 will not be required.
    [10] 10. The vehicle according to claim 8 or 9, wherein the control unit (30) isadapted to determine the amount of energy that will be recovered by the wasteheat recovery system (10) based on estimated stored heat associated with theat least one heat source (24) and a predicted mass flow of the at least one heat source (24).
    [11] 11. The vehicle according to any of claims 8 - 10, wherein the control unit (30)is adapted to control the vehicle speed based on the amount of energy that will be recovered by the waste heat recovery system (10).
    [12] 12. The vehicle according to claim 11, wherein the control unit (30) is adaptedto decrease the vehicle speed prior to the predicted downhill slope, wherein thedecrease depends on the determined amount of energy that will be recoveredby the waste heat recovery system (10) during the downhill slope.
    [13] 13. The vehicle according to any of claims 8-10, wherein, when the vehicle (1)is driving down the slope, the control unit (30) is adapted to disconnect thecombustion engine (2) from the rest of the powertrain (3) and ensure that thecombustion engine (2) is operated with an engine speed which does not exceeda standard idling speed by means of the energy recovered by the waste heat recovery system (10). 31
    [14] 14. The vehicle according to any of claims 8 - 10, wherein, when the vehicle (1)is driving down the slope, the control unit (30) is adapted to turn off thecombustion engine (2) and control the working fluid (WF) in the waste heat recovery system (10) to bypass the expander (16).
    [15] 15. A computer program (P), wherein said computer program comprisesprogram code for causing an electronic control unit (30; 500) or a computer (32;500) connected to the electronic control unit (30; 500) to perform the steps according to any of the claims 1-7.
    [16] 16. A computer program product comprising a program code stored on acomputer-readable medium for performing the method steps according to anyof claims 1-7, when said computer program is run on an electronic control unit(30; 500) or a computer (32; 500) connected to the electronic control unit (30;500).
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN101243243A|2005-06-16|2008-08-13|Utc电力公司|Organic rankine cycle mechanically and thermally coupled to an engine driving a common load|
    DE102008011213A1|2008-02-26|2009-09-10|Gümüs, Cem|Device for usage of braking energy in motor vehicles, has exhaust gas-generating drive motor for driving motor vehicle and unit for usage of energy contained in exhaust gas|
    法律状态:
    优先权:
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    SE1651038A|SE541172C2|2016-07-12|2016-07-12|A method and a vehicle for controlling a WHR-system in response to a determined recoverable energy of a downhill slope|SE1651038A| SE541172C2|2016-07-12|2016-07-12|A method and a vehicle for controlling a WHR-system in response to a determined recoverable energy of a downhill slope|
    DE102017006371.0A| DE102017006371A1|2016-07-12|2017-07-05|A method of controlling a vehicle in conjunction with a downhill slope and such a vehicle|
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