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    • 专利摘要:
    33 Abstract The invention relates to a method for controlling the temperature of a wasteheat recovery system (4) associated with a combustion engine (2), the wasteheat recovery system (4) comprising a working fluid circuit (20); at least oneevaporator (22); an expander (24); a condenser (26) and a pump (30)arranged to pump the working fluid (WF) through the circuit (20), wherein theat least one evaporator (22) is arranged for heat exchange between theworking fluid (WF) and a heat source (32) associated with the combustionengine (2), wherein the condenser (26) of the waste heat recovery system (4)is connected to a coo|ing system (6). The method comprises the steps of:determining (s101) if a combustion engine (2) associated with the waste heatrecovery system (4) is about to be shut down; and controlling (s102) thetemperature in the waste heat recovery system (4) based on whether thecombustion engine (2) is about to be shut down or not. The invention also relates to a vehicle system (4), a vehicle (1) comprising such a system (4), a computer program (P) and a computer program product. (Fig. 2)
    公开号:SE1650132A1
    申请号:SE1650132
    申请日:2016-02-04
    公开日:2017-08-05
    发明作者:Johansson Björn；Höckerdal Erik；Blom Ola
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    A method for controlling the temperature of a waste heat recoverysystem and such a waste heat recovery systemTECHNICAL FIELDThe present invention relates to a method for controlling the temperature of awaste heat recovery system associated with a combustion engine of a vehicle,a waste heat recovery system, a vehicle comprising such a waste heatrecovery system, a computer program and a computer program productaccording to the appended claims.
    BACKGROUNDVehicie irianutacturers are today striving to increase engine efficiency andreduce iuei consumption. This is speciticaiiy an issue fcr ntanufacturers ofheavy vehicies, such as trucks and huses. One way ot irnoroving engineefficiency and fuei consumption is waste heat recovery. in vehicies yirithcornoustion engines sorne oi the energy irorn the iuei is dissioated as heatthrough the exhaust pipes and the engine cooiing systern. By the use of awaste heat recovery systern the heat irorn the exhatist gases rnay instead heused for exarripie to heat various yehicie components or to producerriechanicai work. Such rnechanicai work nray for exarnpie he transierred to theoowertrain and thus he used to prooei the vehicie.
    A waste heat recovery systern typicaiiy corriorises at ieast one heat exohangertransierring heat between a heat source, such as exhaust gases, and aworking fiuid. The heat transfer between the working iiuid and the heat sourceis an exchange of energy resuiting in a change in rtentoerarttire. A waste heatrecovery systern rnay aiso he oased on a Ftankine cycie and thus cornorise aworking iiuid, a pumo for circuiating the tyorking fiuid in a circuit, at ieast oneevaoorator (heat exchanger), an expansion device and a condenser. Theworking fiuid in such waste heat recovery systern is suitaoiy in a iiotiid state tostart yvith. The pump pressurizes the tvorking tiuid which is punieed throughthe evaperater. The working tiuid is heated hy ter examoie exhaust gases iedthrough the evaeorater' ane the »working tiuid thereoy evaoorates. The vapeurmay suhseguentiy he exoanded in the expansion devioe. By means ei theexpansion device the recovered heat rnay tiierehy oe converted intemechanicai work. The vaeeur' is thereatter oeeied in the oendenser, such thatthe working tiuid is brought tiaek te its initiai iieuid state. The cendenser is thustyoieaiiy connected te a eooiing system, yvhioh couid he part et the engineoeoiing system er a separate ceoiing systern.
    The eperating tenioerattire et waste heat recovery systems is nerrnaiiy quitehigh. The therrriai iriertia ot the systern ceuid resuit in a high temperature evenatter the system has heen shut down. Tee high ternperatures ceuid damagethe working tiuid and other comoenents et the waste heat recovery systern. itis therefore important that the viraste heat reeevery system is eeoied downiaetere being shut down.Üeotinient .iifiâutišití/"Stâli A describes a method ter aveiding everheating otan engine coeiing medium usee in an exhaust heat recovery deviee in a hybridvehioie. The exhaust heat is used te heat the ceeiing niediuirr hy means et aheat exehanger. it the temeeirature et the coeiing rrieeiurri is aheve a threshoidtemperature when the vehicie is stepoing and the cernhustien engine is turnedott, the oornhustion engine is driven ey an eiectrio machine to an idiing soeed,such that the exhaust gas yvith a iewer temperature is eeoiirtg the heatexehanger and thus the ceoiing medium.
    SUMMARY OF THE INVENTIONDespite known solutions in the field, there is still a need to develop a methodfor controlling the temperature of a waste heat recovery system associatedwith a combustion engine, which optimizes engine efficiency, fuei consumptionand driver comfort.
    An object of the present invention is to achieve an advantageous method forcontrolling the temperature of a waste heat recovery system, which optimizesengine efficiency and fuei consuinpiicn.
    Another object of the present invention is to achieve an advantageous methodfor controlling the temperature of a waste heat recovery system, whichoptimizes driver comfort.
    Another object of the invention is to achieve an advantageous waste heatrecovery system, which optimizes engine efficiency and fuei consumption.
    A further object of the invention is to achieve an advantageous waste heatrecovery system, which optimizes driver comfort.
    The herein mentioned objects are achieved by a method for controlling thetemperature of a waste heat recovery system, a waste heat recovery system, avehicle, a computer program and a computer program product according to theindependent claims.
    According to an aspect of the present invention a method for controlling thetemperature of a waste heat recovery system associated with a combustionengine is provided. The waste heat recovery system comprises a working f|uidcircuit; at least one evaporator; an expander; a condenser and a pumparranged to pump the working f|uid through the circuit, wherein the at least oneevaporator is arranged for heat exchange between the working f|uid and a heatsource associated with the combustion engine, wherein the condenser of thewaste heat recovery system is connected to a cooling system. The methodcomprises the steps of:- determining if a combustion engine associated with the waste heat recoverysystem is about to be shut down; and- controlling the temperature in the waste heat recovery system based onwhether the combustion engine is about to be shut down or not.
    The waste heat recovery system may be associated with a combustion engineof a vehicle.
    The waste heat recovery system is suitabiy based on the Rankine cycie,breterabiy an organic Rankine cycie. The working iiuid is thus stiitabiy organic,such as ethanoi or Håål-åta. The waste heat recovery system is suitabiyadapted to recover yyaste heat trom the heat source and converting therecovered energy to mechanicat work. The waste heat recovery systern basedon the Rankine oycie is suitabiy contigured such that the working tiuid, suitabiyin a iiduid state, is oumoed through the evaoorator. The yyorkirig tiuid isthereby heated by the heat source connected to the evaoorator and theworking ttuid thus evaoorates. The yaoour is then exoanded in the exoanderwhereby meohahioat work is produced. The rnechanicai work may tor exarnoiebe trarisierred to the crankshatt ot the combustion engine and thus be used toorooei the yehicie or the iheohanicai work may be used to drive tor exarnoie agenerator. The vapour' is thereatter oooied in the condenser by heat exchangewith a oooiihg tiuid in the cooiing system., such that the working ftuid is broughtback to its initiai tiouid state. The evaoorator is suitabiy a heat exchangerconnected to the heat source and the yyorking tiuid circuit. The tyaste heatrecovery system rnay cornorise a oiuraiity ot evaborators, each connected to aseparate heat source.
    The waste heat recovery system is typically operating mainly when thecombustion engine is operating since the heat source is associated with thecombustion engine. Thus, the waste heat recovery system should commonlybe shut down when the combustion engine is turned off. The operatingtemperature ot the waste heat recovery system is rtormaiiy quite htgh and thethermat ihertta of the waste heat recovery system restitts iri a high temperattireeveh after the system has been shut eewh. Such high temperatures eouiddamage the werkihg ftuid and ether cempehehts ef the waste heat receverysystern. it is therefore intportaht that the waste heat recovery system is eoeieddewri before being shut devvrt. However, the efficiency of the waste heatrecovery system is increased with evaporator temperature. The temperature ofthe evaporator should therefore be maintained as high as possible duringnormal operation. The waste heat recovery system should thus not beunnecessarily cooled down. By determining if the combustion engineassociated with the system is about to be shut down and controlling thetemperature in the waste heat recovery system based on whether thecombustion engine is about to be shut down or not, the functionality of thewaste heat recovery system is ensured and engine efficiency and fuelconsumption is optimized. By determining if the combustion engine is about toshut down, the need for shutdown of the waste heat recovery system ispredicted. The temperature in the waste heat recovery system is thus suitablycontrolled further based on the prediction of whether the waste heat recoverysystem is about to be shut down or not.
    The method steps are suitably performed by means of a control unit connectedto the combustion engine, the waste heat recovery system and the coolingsystem.
    The step to determine if the combustion engine is about to be shut downsuitably comprises to receive a shutdown signal from another vehicle system.The shutdown signal thus indicates that the combustion engine is about to beshut down and no signal would indicate that the combustion engine is notabout to be shut down. The step to determine if the combustion engine isabout to be shut down may comprise to determine if the vehicle is standing still,if the vehicle parking brake is activated, if the vehicle is at its final destinationaccording to a navigation system and/or if the vehicle is at a required stopaccording to a tachograph. The step to determine if the combustion engine isabout to be shut down may be based on the topography of the vehicle route. ltmight, for example, be desirable to turn off the combustion engine when thevehicle is rolling downhill. lt may also be determined that the combustionengine is about to be shut down based on other vehicle operation factors.
    According to an aspect of the invention the step to control the temperature inthe waste heat recovery system comprises to control the heat sourceassociated with the combustion engine. The heat source associated yvith theeernbustien engine may ter example be exhaust gases trern the eembustienengine. The heat transfer bettyeen the werking ftuid and the heat seuree is anexchange sf energy resutting in a change in temperature. Thus, the heatseurce is previding the energy erttering the waste heat reeevery system andthe energy is ieaving the waste heat recovery system as rneehanicai work viathe expander and as heat via the cendenser and the eoeiing system. Thetemperature in the tfvaste heat recovery system titus depends en the antount ofenergy erttering the system and the arneurtt ef energy ieaving the system. Bycentreitiitg the heat source the temperature in the yvaste heat reeevery systemmay be increased er reduced.
    According to an aspect of the invention the step to control the temperature inthe waste heat recovery system comprises to maintain as high temperature aspossible, if the combustion engine is not about to be shut down. This way, thetemperature of the evaporator is maintained as high as possible and theefficiency of the waste heat recovery system is optimized during normaloperation. By controlling the temperature in the waste heat recovery systemsuch that it is maintained as high as possible when it is determined that thecombustion engine will not be turned off, engine efficiency is optimized. lf it isdetermined that the combustion engine is about to be shut down, it may alsobe determined how long the combustion engine is likely to be shut down. Thetemperature in the waste heat recovery system is thus suitably controlledbased on whether the combustion engine is about to be shut down or not andif so, how long it is likely to be shut down. Thus, the step to control thetemperature in the waste heat recovery system comprises to maintain as hightemperature as possible, if the combustion engine is not about to be shut downor if the combustion engine is about to be shut down for a shorter time periodthan a minimum time period. The minimum time period is suitably a time periodafter which it may be necessary to shut down the waste heat recovery system.When the vehicle is standing still, there is a possibility that the combustionengine and thus the waste heat recovery system will be turned off and it mighttherefore be advantageous to reduce the temperature in the waste heatrecovery system. However, when the vehicle is stopped at a stop sign or atraffic light the combustion engine is not necessarily turned off or it is onlyturned off for a short period of time and the waste heat recovery systemtherefore does not have to be shut down. The temperature of the waste heatrecovery system should therefore be maintained as high as possible toachieve an as efficient heat exchange as possible when the vehicle is movingagain.
    According to an aspect of the invention the step to control the temperature inthe waste heat recovery system comprises to reduce the temperature prior tocombustion engine shutdown, if the combustion engine is about to be shutdown. Suitably, the step to control the temperature in the waste heat recoverysystem comprises to reduce the temperature prior to combustion engineshutdown, if the combustion engine is about to be shut down for a time periodlonger than the minimum time period. When the combustion engine is turnedoff, the heat source no longer heats the evaporator but the thermal inertia ofthe evaporator means that the evaporator will maintain a very hightemperature for a certain time. The temperature in the waste heat recoverysystem therefore needs to be reduced before the system is shut down. lt isthus crucial that circulation of the working fluid in the waste heat recoverysystem and the cooling fluid in the cooling system is maintained until a safetemperature in the waste heat recovery system is reached. The cooling systemconnected to the condenser may be part of the combustion engine coolingsystem or a separate cooling system. The cooling fluid in the cooling system iscirculated by a cooling pump, which may be driven by the combustion engineor by an electric machine. ln the case where the cooling pump is driven by thecombustion engine it is crucial that the waste heat recovery system is cooleddown prior to engine shutdown, since the cooling pump will stop circu|ating thecooling fluid when the combustion engine is turned off. ln the case where thecooling pump is driven by an electric machine the waste heat recovery systemmay be cooled down after engine shutdown. However, the driver will then haveto wait until the waste heat recovery system has reached a sufficiently lowtemperature to be safely shut down. Also, if the waste heat recovery system iscooled down after engine shutdown, the electric machine driving the coolingpump will use energy from an energy storage such as a battery in the vehicle.This is not advantageous. By reducing the temperature in the waste heatrecovery system prior to combustion engine shutdown, the driver comfort isincreased since the waste heat recovery system may be shut down essentiallyat the same time as the combustion engine.
    The cooling system connected to the condenser suitably comprises a coolingcircuit, a cooling pump arranged to circulate a cooling fluid through the coolingcircuit and a radiator arranged for cooling the cooling fluid. The cooling systemmay further comprise a bypass circuit, a first valve unit and a second valve unit.
    The first valve unit is suitably arranged to control the flow of cooling fluidthrough the radiator and the bypass circuit respectively. The second valve unitis suitably arranged to control the flow of cooling fluid passing through thecondenser of the waste heat recovery system. By controlling the first valve unitand the second valve unit, the cooling fluid may be controlled to bypass theradiator and/or the condenser of the waste heat recovery system.
    According to an aspect of the invention the step to reduce the temperature inthe waste heat recovery system prior to engine shutdown, when thecombustion engine is about to be shut down, comprises to control the heatsource to bypass the evaporator if the temperature of the heat source is higherthan the temperature of the evaporator. This way, the heat source will nolonger heat the evaporator and the temperature of the evaporator, and thus thewaste heat recovery system, will be reduced. However, if the temperature ofthe heat source is lower than the temperature of the evaporator, the heatsource is suitably controlled to flow through the evaporator. This way, the heatsource will cool the evaporator and the temperature in the waste heat recoverysystem will thereby be reduced. ln the case where the heat source is exhaustgases from the combustion engine, the exhaust gases may be directed by athrottle to bypass the evaporator when the temperature of the exhaust gases ishigher than the temperature of the evaporator and to flow through theevaporator when the temperature of the exhaust gases is lower than theevaporator temperature. This way, the temperature in the waste heat recoverysystem is reduced prior to combustion engine shutdown, when the combustionengine is about to be shut down. The cooling of the evaporator by means ofthe exhaust gases may be accelerated by increasing the combustion engineidling speed when the vehicle is standing still. By increasing the idling speed ofthe combustion engine the amount of the heat source passing through theevaporator will be increased and the temperature of the evaporator will bereduced more quickly.
    According to an aspect of the invention the step to reduce the temperature inthe waste heat recovery system prior to engine shutdown, when thecombustion engine is about to be shut down, comprises to minimize thetemperature of the cooling fluid in the cooling system. By minimizing thetemperature of the cooling fluid, the heat exchange between the working fluidin the waste heat recovery system and the cooling fluid in the cooling systemwill be increased. The temperature of the waste heat recovery system willthereby be reduced. The temperature of the cooling fluid in the cooling systemis suitably minimized by controlling the cooling system such that the radiator isused with full capacity. This may be done by increasing the flow of cooling fluidthrough the radiator, for example by controlling the first valve unit in the coolingsystem. The flow through the radiator may also be increased by increasing thecombustion engine idling speed. When the vehicle is standing still thecombustion engine is typically running with an idling speed. The cooling pumpis suitably connected to the crankshaft of the combustion engine such that byincreasing the idling speed of the combustion engine, the cooling pump willpump an increased amount of cooling f|uid through the cooling circuit. Thisway, the flow through the radiator is increased and the temperature of thecooling f|uid is minimized.
    According to an aspect of the invention the step to reduce the temperature inthe waste heat recovery system prior to engine shutdown, when thecombustion engine is about to be shut down, comprises to increase the flow ofcooling f|uid through the condenser. By increasing the flow of cooling f|uidthrough the condenser of the waste heat recovery system, the heat exchangebetween the working f|uid and the cooling f|uid is increased and the cooling ofthe working f|uid is increased. The temperature of the waste heat recoverysystem is thereby reduced. The flow of cooling f|uid through the condenser issuitably increased by controlling the second valve unit in the cooling system.
    According to an aspect of the invention the step to reduce the temperature inthe waste heat recovery system prior to engine shutdown, when thecombustion engine is about to be shut down, comprises to increase the flow ofworking f|uid through the circuit of the waste heat recovery system. Byincreasing the flow of working f|uid through the circuit of the waste heatrecovery system, the cooling down of the evaporator may be accelerated andthe temperature in the waste heat recovery system is quickly reduced. Theflow of working f|uid is suitably increased by increasing the speed of the pumpof the waste heat recovery system.
    The various ways of reducing the temperature in the waste heat recoverysystem mentioned herein may be combined or used separately. For example,when a combustion engine shutdown has been predicted, the heat source maybe controlled to reduce the temperature of the evaporator and the coolingsystem may at the same time be controlled to reduce the temperature of the11cooling fluid. This way, an efficient way of reducing the temperature in thewaste heat recovery system, prior to combustion engine shutdown, is achieved.lf the temperature in the waste heat recovery system is not too high, there isno need to reduce the temperature further prior to combustion engineshutdown. Thus, the temperature in the waste heat recovery system should bereduced only when the current temperature in the waste heat recovery systemis above a critical temperature. The critical temperature may be between 100-150 degrees Celsius.
    According to an aspect of the invention the temperature in the waste heatrecovery system is reduced, such that a target temperature is reached. Thetarget temperature is suitably below a normal operation temperature, andsubstantially corresponds to the critical temperature defined above. Therefore,the target temperature may be between 100-150 degrees Celsius. The targettemperature is suitably a temperature desired for enabling a safe shutdown ofthe waste heat recovery system. The normal operation temperature in thewaste heat recovery system is preferably between 200-300 degrees Celsius,and depends on the type of working fluid in the waste heat recovery system.The target temperature and the normal operation temperature are suitablyassociated with the working fluid immediately downstream of the evaporator orimmediately downstream of the condenser.
    According to an aspect of the invention the method comprises the step todetermine in which vehicle performance mode the vehicle is operating. Suchvehicle performance mode may be an economy mode, a normal mode or apower mode. Depending on the vehicle performance mode different aspectsare considered when controlling the vehicle. For example, a vehicle operatingin an economy mode is controlled such that the fuel consumption is minimizedand a vehicle operating in a power mode is controlled such that the enginepower is maximized. This is suitably considered when determining how tocontrol the temperature in the waste heat recovery system. When operating in12an economy mode the fuel consumption should be minimized and thetemperature in the waste heat recovery system is therefore suitably reducedwithout increasing the combustion engine idling speed. Also, increasing thespeed of the pump in the waste heat recovery system to increase the flow ofworking fluid may affect the fuel consumption and may therefore be avoidedwhen operating in an economy mode. When operating in a power mode thecooling down of the waste heat recovery system may on the other hand beaccelerated by increasing the combustion engine idling speed. Thus, the stepto control the temperature in the waste heat recovery system is suitably furtherbased on the vehicle performance mode the vehicle is operating in.
    According to an aspect of the invention, shutdown of the combustion engine isdelayed until the temperature of the waste heat recovery system is below atarget temperature. ln the case where it has been determined that thecombustion engine is about to be shut down, the temperature in the wasteheat recovery system is suitably reduced to a target temperature prior to theengine shutdown. The target temperature is suitably a desired temperatureenabling a safe shut down of the waste heat recovery system. lf engineshutdown is requested before the temperature in the waste heat recoverysystem has been reduced to the target temperature, the combustion enginemay be controlled to maintain an idling speed until the target temperature isreached. When the target temperature has been reached the combustionengine is suitably automatically shut down. Engine shutdown may berequested by the driver of the vehicle manoeuvring an ignition key/button.Engine shutdown may alternatively be requested by a vehicle system, such asan engine control system in a hybrid vehicle. lf the combustion engine iscontrolled to maintain the idling speed even when engine shutdown isrequested, this is suitably indicated to the driver through a display or similar.
    According to an aspect of the invention the step to maintain as hightemperature as possible in the waste heat recovery system when thecombustion engine is not about to be shut down, comprises to control the heat13source to bypass the evaporator if the temperature of the heat source is lowerthan the temperature of the evaporator. lf the vehicle is standing still thecombustion engine is typically operating with an idling speed. The temperatureof the heat source associated with the combustion engine is thereby lowerthan during normal operation. By controlling the heat source to bypass theevaporator when the temperature is lower than the temperature of theevaporator, the heat source will not cool the evaporator. The temperature ofthe waste heat recovery system will thereby be maintained as high as possible.However, if the temperature of the heat source is higher than the temperatureof the evaporator, the heat source is suitably controlled to flow through theevaporator. This way, the heat source will heat the evaporator and thetemperature in the waste heat recovery system will thereby be maintained ashigh as possible.
    According to an aspect of the invention a waste heat recovery systemassociated with a combustion engine of a vehicle is provided. The waste heatrecovery system comprises a working fluid circuit; at least one evaporator; anexpander; a condenser and a pump arranged to pump the working fluidthrough the circuit, wherein the at least one evaporator is arranged for heatexchange between the working fluid and a heat source associated with thecombustion engine, wherein the condenser of the waste heat recovery systemis connected to a cooling system. The waste heat recovery system furthercomprises a control unit adapted to determine if a combustion engineassociated with the system is about to be shut down; and control thetemperature in the waste heat recovery system based on whether thecombustion engine is about to be shut down or not.
    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 in14multiple steps. Furthermore, the waste heat recovery system may compriseone or more expanders. The expander may be a turbine or a piston expander.
    The vehicle system may be arranged in a hybrid vehicle. Such hybrid vehiclecomprises an electric machine for propulsion, in addition to the combustionengine.
    The cooling system suitably comprises a cooling circuit connected to thecondenser of the waste heat recovery system, a cooling pump arranged tocirculate a cooling fluid through the cooling circuit and a radiator arranged forcooling the cooling fluid. The cooling pump is suitably driven by thecombustion engine. The cooling system may further comprise a bypass circuit,a first valve unit and a second valve unit. The first valve unit is suitablyarranged to control the flow of cooling fluid through the radiator and the bypasscircuit respectively. The second valve unit is suitably arranged to control theflow of cooling fluid passing through the condenser of the waste heat recoverysystem.
    The control unit is suitably connected to the waste heat recovery system, thecombustion engine and the cooling system. The control unit is suitablyconnected to the evaporator, the expander and the pump of the waste heatrecovery system. The control unit is suitably connected to the cooling pump,the first valve unit and the second valve unit of the cooling system. The controlunit may be the engine control unit or may comprise a plurality of differentcontrol units. A computer may be connected to the control unit.
    The control unit is suitably adapted to determine if the combustion engine isabout to be shut down based on a received shutdown signal from anothervehicle system. lf the control unit receives the shutdown signal the combustionengine is about to be shut down and if the control unit does not receive ashutdown signal the combustion engine is not about to be shut down. Thecontrol unit may be adapted to determine if the combustion engine is about tobe shut down based on if the vehicle is standing still, if the vehicle”s parkingbrake is activated, if the vehicle is at its final destination according to anavigation system and/or if the vehicle is at a required stop based on atachograph. The control unit may also be adapted to determine if thecombustion engine is about to be shut down based on other vehicle operatingfactors.
    The control unit is suitably adapted to identify that the vehicle is standing stillbased on signals from sensor devices connected to the driving wheels of thevehicle. The control unit may be adapted to determine if the vehicle is standingstill by determining the engine speed. The engine speed is suitably an idlingspeed when the vehicle stands still. The idling speed associated with thecombustion engine is suitably known and stored in the control unit.
    The control unit is suitably adapted to control the temperature in the wasteheat recovery system by controlling the heat source associated with thecombustion engine.
    The control unit is suitably adapted to determine the temperature of theevaporator, the heat source and the cooling fluid in the cooling system.
    The control unit is suitably adapted to maintain as high temperature aspossible in the waste heat recovery system, if the combustion engine is notabout to be shut down. ln order to maintain as high temperature in the wasteheat recovery system as possible the control unit is suitably adapted to controlthe heat source to bypass the evaporator if the temperature of the heat sourceis lower than the temperature of the evaporator. The control unit is alsoadapted to control the heat source to flow through the evaporator if thetemperature of the heat source is higher than the temperature of theevaporator in order to maintain as high temperature as possible.16The control unit is suitably adapted to reduce the temperature in the wasteheat recovery system prior to combustion engine shutdown, if the combustionengine is about to be shut down. ln order to reduce the temperature in thewaste heat recovery system, the control unit is suitably adapted to control theheat source to bypass the evaporator if the temperature of the heat source ishigher than the temperature of the evaporator. The control unit is also adaptedto control the heat source to pass through the evaporator if the temperature ofthe heat source is lower than the temperature of the evaporator. The controlunit is further adapted to minimize the temperature of the cooling fluid in thecooling system and/or increase the flow of cooling fluid through the condenserand/or increase the flow of working fluid through the circuit of the waste heatrecovery system in order to reduce the temperature in the waste heat recoverysystem. ln order to accelerate the temperature reduction in the waste heatrecovery system, the control unit is suitably further adapted to increase theidling speed of the combustion engine and thereby increase the flow of coolingfluid and exhaust gases.ln the case where a combustion engine shutdown has been predicted, thecontrol unit is suitably adapted to delay shutdown of the combustion engineuntil the temperature of the waste heat recovery system is below a targettempefatU FG.
    Further objects, advantages and novel features of the present invention willbecome apparent to one skilled in the art from the following details, and alsoby putting the invention into practice. Whereas the invention is describedbelow, it should be noted that it is not restricted to the specific detailsdescribed. Specialists having access to the teachings herein will recognisefurther applications, modifications and incorporations within other fields, whichare within the scope of the invention.
    BRIEF DESCRIPTION OF THE DRAWINGS17For 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 notationsdenote similar items in the various diagrams, 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 controllingthe temperature of a waste heat recovery system according to anembodiment of the invention; andFigure 4 schematically illustrates a control unit or computer according to anembodiment of the invention.
    DETAILED DESCRIPTION OF THE DRAWINGSFigure f sohenfaticafiy shows a side view of a vehicle f according to anembodiment of the invention. The vehicie f inoiudes a combustion engine 2, awaste heat recovery system 4 associated with the confbusfion engine 2 and aoooiing systern 5 connected to the waste heat recovery systern 4. The vehicie1 further coinprises a gearbox 8 ooniteotecf to the driving wheefs to of thevehioie 1. The vehicle 1 may be a heavy vehicle, e.g. a truck or a bus. Thevehicle 1 may alternatively be a passenger car. The vehicle may be a hybridvehicle comprising an electric machine (not shown) in addition to thecombustion engine 2.
    Figure 2 schematiceiiy shows a waste heat recovery system 4 associated witha combustion engine 2 of a vehicle 1 according to an embodiment of the18invention. The waste heat recovery system 4 is suitably arranged in a vehicleas described in Figure 1.
    The waste heat recovery system 4 comprises a working fluid circuit 20; anevaporator 22; an expander 24; a condenser 26; a reservoir 28 for a workingfluid WF and a pump 30 arranged to pump the working fluid WF through thecircuit 20, wherein the evaporator 22 is arranged for heat exchange betweenthe working fluid WF and a heat source 32 associated with the combustionengine 2. The condenser 26 of the waste heat recovery system 4 is connectedto a coo|ing system 6. The coo|ing system 6 may be a part of a combustionengine coo|ing system and may thus cool both the combustion engine 2 andthe condenser 26 of the waste heat recovery system 4. Alternatively, thecoo|ing system 6 is a separate coo|ing system. The waste heat recoverysystem 4 comprises a control unit 40 adapted to determine if a combustionengine 2 associated with the waste heat recovery system 4 is about to be shutdown; and control the temperature in the waste heat recovery system 4 basedon whether the combustion engine 2 is about to be shut down or not. This way,a waste heat recovery system 4 is achieved, which ensures the functionality ofthe waste heat recovery system 4 and optimizes the engine efficiency and fuelconsumption. The heat source 24 connected te the evaporator 14 rney beexhaust geses frem the eentbustiert engine 2, an exhaiist ges recircuiatiensystem (EGR), the ceoiiitg titiid of the combustion engine 2, the combustionengine 2 itseif er eny other hot eompenent associated with the cernbustienengine 2.
    The coo|ing system 6 comprises a coo|ing circuit 50 connected to thecondenser 26 of the waste heat recovery system 4, a coo|ing pump 52arranged to circulate a coo|ing fluid CF through the coo|ing circuit 50 and aradiator 54 arranged for coo|ing the coo|ing fluid CF leaving the combustionengine 2. The coo|ing pump 52 is driven by the combustion engine 2. Thecoo|ing system 6 further comprises a bypass circuit 56, a first valve unit 58 anda second valve unit 60. The first valve unit 58 is suitably arranged to control19the flow of cooling fluid CF through the radiator 54 and the bypass circuit 56respectively. The second valve unit 60 is suitably arranged to control the flowof cooling fluid CF passing through the condenser 26 of the waste heatrecovery system 4. The cooling fluid CF is herein illustrated as arrows alsoshowing the flow direction of the cooling fluid CF through the cooling circuit 50.
    The heat source 32 connected to the evaporator 22 is herein exernpiiiied asexhaust gases front the cornbustion engine 2. The exhaust gases S2 areiiiustrated as an arrow in an exhaust pipe, wherein the exhatist gases 32 inaybe controiied to pass through the evaporator 22 or to bypass the evaoorator22. The waste heat recovery systern 4 rnay cornprise a piuraiity of et/aporators22, each connected to a different heat source 32. The evaporator 22 Es suitabiya heat exchanger connected to the heat source 32 and the working fiuid circuit2ít. The heat transfer between the working fiuid WF and the heat source 32 isan exchange ot energy resuiting in a change in temperature. The tyaste heatrecovery systern 4 Es suitabiy based on an organic Rankine cycie. The workingfiuid Wi: is thus suitabiy organic, such as ethanoi or R245ta. The waste heatrecovery systern 4 Es thus configured such that the iiouid working iiuid WF ispuntped froin iow pressure to high pressure and enters the evaporator 22. Theworking fiuid WF is thereby heated by the heat source 32 connected to theevaporator 22 and the yvorking iiuid WF is thus eyaporated. The vapour Es thenexpanded in the expander 24 witereby rnechanicai work is produced and thetemperature and the pressure oi the vaoour Es decreased. The ntechanicaivtroifk rnay tor exarnpie be transferred to the crankshatt of the contbustiortengine 2 and thus be used to orobei the vehicie t or the inechanicai work rnaybe used to drive for exantpie a generator. The vapour thereafter enters thecondenser 26 where condensation through heat exchange between the vapourand the cooiing tiuid CF of the cooiing systern 6 orings the working fiuid WPback to its initiai iiouid state. Thus, the heat source 32 is providing the energyentering the waste heat recovery systern 4 and the energy is ieaving the tyasteheat recovery systern 4 as rnechanicai tyork via the expander 24 and as heatvia the cooiing systern 6 cooiing the condenser 26. The terrioerature in the»waste heat recovery system 4 thus depends en the amount of energy enteringthe system 4 and the arnount of energy leaving the system 4.lt is crucial that the waste heat recovery system 4 is cooled down before beingshut down. The thermal inertia of for example the evaporator 22 will otherwisecause a high temperature in the waste heat recovery system 4 after shutdown.A too high temperature in the waste heat recovery system 4 may damage theworking f|uid WF and other components of the waste heat recovery system 4.Since the cooling pump 52 is driven by the combustion engine 2 it is importantthat the waste heat recovery system 4 is cooled down prior to combustionengine shutdown. When the combustion engine 2 is turned off the coolingpump 52 will stop circulating the cooling f|uid CF and the cooling of thecondenser 26 will thereby stop. lt is thus difficult to reduce the temperature inthe waste heat recovery system 4 when the combustion engine 2 has beenturned off.
    Only vapour should enter the expander 24 and the waste heat recoverysystem 4 therefore comprises a bypass arrangement 25, such that in the casewhere the working f|uid WF is still in a liquid state downstream of theevaporator 22, the working f|uid WF is bypassing the expander 24 through thebypass arrangement 25.
    The pump 3G pressurizing and circulating the working fiuid WF Es stiitablyeiectrically driven.
    The waste heat recovery system 4 may comprise one or moreevaporators/heat exchangers 22. The waste heat recovery system 4 may forexample comprise a recuperator arranged to pre-heat the working f|uid WFbefore entering the evaporator 22. The waste heat recovery system 4 may alsocomprise one or more condensers 26, such that cooling down of the workingf|uid WF may be performed in multiple steps. Furthermore, the waste heat21recovery system 4 may comprise one or more expanders 24. The expander 24may be a turbine or a piston expander.
    The control unit 40 is arranged in connection with combustion engine 2, thewaste heat recovery system 4 and the cooling system 6. The control unit maybe arranged in connection with the evaporator 14, the expander 16 and thepump 22 of the waste heat recovery system 4. The control unit may bearranged in connection with the first valve unit 58 and the second valve unit 60of the cooling system 6. A computer 42 may be connected to the control unit40. The control unit 40 is further adapted to control the temperature in thewaste heat recovery system 4 by controlling the heat source 32 associatedwith the combustion engine 2. The control unit 40 is adapted to determine thetemperature of the evaporator 22, the heat source 32 and the cooling fluid CFin the cooling system 6. The control unit 40 is adapted to maintain as hightemperature as possible in the waste heat recovery system 4, if it isdetermined that the combustion engine is not about to shut down.
    The control unit 40 is adapted to reduce the temperature in the waste heatrecovery system 4 prior to combustion engine shutdown, if it is determined thatthe combustion engine is about to shut down. The control unit 40 is furtheradapted to minimize the temperature of the cooling fluid CF in the coolingsystem 6 and/or increase the flow of cooling fluid CF through the condenser 26and/or increase the flow of working fluid WF through the circuit 20 of the wasteheat recovery system 4 in order to reduce the temperature in the waste heatrecovery system 4. ln order to accelerate the temperature reduction in thewaste heat recovery system 4, the control unit 40 is further adapted toincrease the idling speed of the combustion engine 2 and thereby increase theflow of cooling fluid CF and exhaust gases 32. The control unit 40 may also beadapted to delay combustion engine shutdown until the temperature of thewaste heat recovery system 4 is below a target temperature.22Figure 3 shows a flowchart for a method for controlling the temperature of awaste heat recovery system 4 associated with a combustion engine 2 of avehicle 1. The waste heat recovery system 4 is suitably configured asdescribed in Figure 2. The method comprises the steps of; determining s101 ifa combustion engine 2 associated with the waste heat recovery system 4 isabout to be shut down; and controlling s102 the temperature in the waste heatrecovery system 4 based on whether the combustion engine 2 is about to beshut down or not.
    The eperatihg temperature of the waste heat recovery system 4 is nerntaityquite high and the therntai inertia et the waste heat recovery system 4 resuitsin a high tentperattere even after the system 4 has been shut down. Such highternperatures ceuid damage the working ftuid WF and other eeihpeheitts et thewaste heat recovery system 4. it is therefere important that the waste heatrecovery systern 4 is eeeied down hefere being shut dottrri. However, theefficiency of the waste heat recovery system 4 is increased with thetemperature of evaporator 22. The temperature of the evaporator 22 shouldtherefore be maintained as high as possible during normal operation. Thewaste heat recovery system 4 should thus not be unnecessarily cooled down.By determining if the combustion engine 2 is about to be shut down andcontrolling the temperature in the waste heat recovery system 4 based onwhether the combustion engine 2 is about to be shut down or not, thefunctionality of the waste heat recovery system 4 is ensured and engineefficiency and fuel consumption is optimized. By determining if the combustionengine 2 is about to shut down, a shutdown of the waste heat recovery system4 is predicted. The temperature in the waste heat recovery system 4 is thussuitably controlled based on whether there is a need for the waste heatrecovery system 4 to be shut down or not.
    The method steps are suitably performed by means of the control unit 40connected to the combustion engine 2, the waste heat recovery system 4 andthe cooling system 6.23The step to determine s101 if the combustion engine 2 is about to be shutdown is suitably based on a shutdown signal from another vehicle system. lfthe control unit 40 receives a shutdown signal the combustion engine 2 isabout to be shut down and if the control unit 40 does not receive a shutdownsignal the combustion engine 2 is not about to be shut down. The step todetermine s101 if the combustion engine 2 is about to be shut down maycomprise to determine if the vehicle 1 is standing still, if the vehicle parkingbrake is activated, if the vehicle 1 is at its final destination according to anavigation system and/or if the vehicle 1 is at a required stop according to atachograph. The control unit 40 may also determine if the combustion engine 2is about to be shut down based on other vehicle operation factors.
    The step to control s102 the temperature in the waste heat recovery system 4may comprise to control the heat source 32 associated with the combustionengine 2. The heat source 32 associated with the combustion engine 2 rnay torexampie be exhaust gases irom the combustion engine 2. The heat source 32is providing the energy entering the waste heat recovery system 4 and theenergy is ieaving the waste heat recovery system 4 as ntecttantcai work via tiieexpander 24 and as heat via the oooiing systern 6. The temperature in thewaste heat recovery system 4 thus deeends on the antount of energy enteringthe systern 4 and the amount ot energy ieaving the system 4. By eontroiiirtgthe heat source 32 the temperature in the waste heat recovery system 4 inayhe increased or reduced.
    The step to control s102 the temperature in the waste heat recovery system 4suitably comprises to maintain as high temperature as possible, if thecombustion engine is not about to be shut down. This way, the temperature ofthe evaporator 22 is maintained as high as possible and the efficiency of thewaste heat recovery system 4 is optimized during normal operation. Bycontrolling the temperature in the waste heat recovery system 4 such that it is24maintained as high as possible when it is determined that the combustionengine 2 will not be turned off, engine efficiency is optimized.
    The step to control s102 the temperature in the waste heat recovery system 4suitably comprises to reduce the temperature prior to combustion engineshutdown, if the combustion engine is about to be shut down. The waste heatrecovery system 4 is operating mainly when the combustion engine 2 isoperating. Thus, the waste heat recovery system 4 is commonly shut downwhen the combustion engine 2 is turned off. When the combustion engine 2 isturned off, the heat source 32 no longer heat the evaporator 22 but the thermalinertia of the evaporator 22 means that the evaporator 22 will maintain a veryhigh temperature for a certain time. The temperature of the waste heatrecovery system 4 therefore needs to be reduced before the system 4 is shutdown. lt is thus crucial that circulation of the working fluid WF and the coolingfluid CF in the cooling system 6 is maintained until a safe temperature in thewaste heat recovery system 4 is reached. When the cooling pump 52 of thecooling system 6 is driven by the combustion engine 2 it is crucial that thewaste heat recovery system 4 is cooled down prior to combustion engineshutdown, since the cooling pump 52 will stop circulating the cooling fluid CFwhen the combustion engine 2 is turned off. Also, by reducing the temperaturein the waste heat recovery system 4 prior to combustion engine shutdown, thedriver comfort is increased since the waste heat recovery system 4 may beshut down essentially at the same time as the combustion engine 2.
    The step to reduce the temperature in the waste heat recovery system 4 priorto engine shutdown, when the combustion engine is about to be shut down,suitably comprises to control the heat source 32 to bypass the evaporator 22 ifthe temperature of the heat source 32 is higher than the temperature of theevaporator 22. This way, the heat source 32 will no longer heat the evaporator22 and the temperature of the evaporator 22, and thus the waste heat recoverysystem 4, will be reduced. The control unit 40 suitably determines thetemperature of the evaporator 22 and the heat source 32. However, if thetemperature of the heat source 32 is lower than the temperature of theevaporator 22, the heat source 32 is suitably controlled to flow through theevaporator 22. This way, the heat source 32 will cool the evaporator 22 andthe temperature in the waste heat recovery system 4 will thereby be reduced.The cooling of the evaporator 22 by means of the heat source 32 may beaccelerated by increasing the combustion engine idling speed. By increasingthe idling speed of the combustion engine 2 the amount of the heat source 32passing through the evaporator 22 will be increased and the temperature ofthe evaporator 22 will be reduced more quickly.
    The step to reduce the temperature in the waste heat recovery system 4 priorto engine shutdown, when the combustion engine is about to be shut down,suitably comprises to minimize the temperature of the cooling fluid CF in thecooling system 6. By minimizing the temperature of the cooling fluid CF, theheat exchange between the working fluid WF in the waste heat recoverysystem 4 and the cooling fluid CF will be increased. The temperature of thewaste heat recovery system 4 will thereby be reduced. The temperature of thecooling fluid CF in the cooling system 6 is suitably minimized by controlling thecooling system 6 such that the radiator 54 is used with full capacity. This maybe done by increasing the flow of cooling fluid CF through the radiator 54, forexample by controlling the first valve unit 58 in the cooling system 6. The flowthrough the radiator 54 may also be increased by increasing the engine idlingspeed. When the vehicle 1 is standing still the combustion engine 2 is typicallyrunning with an idling speed. The cooling pump 52 is suitably connected to thecrankshaft of the combustion engine 2 such that by increasing the idling speedof the combustion engine 2, the cooling pump 52 will pump an increasedamount of cooling fluid CF through the cooling circuit 50. This way, the flowthrough the radiator 54 is increased and the temperature of the cooling fluidCF is minimized.
    The step to reduce the temperature in the waste heat recovery system 4 priorto engine shutdown, when the combustion engine is about to be shut down,26suitably comprises to increase the flow of cooling fluid CF through thecondenser 26. By increasing the flow of cooling fluid CF through the condenser26 of the waste heat recovery system 4, the heat exchange between theworking fluid WF and the cooling fluid CF is increased and the cooling of theworking fluid WF is increased. The temperature of the waste heat recoverysystem 4 is thereby reduced. The flow of cooling fluid CF through thecondenser 26 is suitably increased by controlling the second valve unit 60 inthe cooling system 6.
    According to an aspect of the invention the step to reduce the temperature inthe waste heat recovery system 4 prior to engine shutdown, when thecombustion engine is about to be shut down, comprises to increase the flow ofworking fluid WF through the circuit 20 of the waste heat recovery system 4.By increasing the flow of working fluid WF through the circuit 20 of the wasteheat recovery system 4, the evaporator 22 may be cooled by the working fluidWF with increased speed and the temperature of the waste heat recoverysystem 4 is quickly reduced. The flow of working fluid WF is suitably increasedby increasing the speed of the pump 30 of the waste heat recovery system 4.
    The method may comprise the step to determine in which vehicle performancemode the vehicle 1 comprising the vehicle system 10 is operating. Suchvehicle performance mode may be an economy mode, a normal mode or apower mode. Suitably, the step of controlling the temperature in the waste heatrecovery system 4 is further based on the vehicle performance mode in whichthe vehicle 1 is operating. When operating in an economy mode the fuelconsumption should be minimized and the temperature in the waste heatrecovery system 4 is therefore suitably reduced without increasing thecombustion engine idling speed. Also, increasing the speed of the pump 30 inthe waste heat recovery system 4 to increase the flow of working fluid WF mayaffect the fuel consumption and may therefore be avoided when operating inan economy mode. When operating in a power mode the cooling down of the27waste heat recovery system 4 may on the other hand be accelerated byincreasing the combustion engine idling speed.
    Suitably, shutdown of the combustion engine 2 is delayed until the temperatureof the waste heat recovery system 4 is below a target temperature. ln the casewhere it has been determined that the combustion engine 2 is about to be shutdown, the temperature in the waste heat recovery system 4 is suitably reducedto a target temperature prior to the engine shutdown. The target temperature issuitably a desired temperature for safe shut down of the waste heat recoverysystem 4. lf engine shutdown is requested before the temperature in the wasteheat recovery system 4 has been reduced to the target temperature, thecombustion engine 2 may be controlled to maintain an idling speed until thetarget temperature is reached. When the target temperature has been reachedthe combustion engine 2 is automatically shut down. Engine shutdown may berequested by the driver of the vehicle 1 manoeuvring an ignition key/button.Engine shutdown may alternatively be requested by a vehicle system, such asan engine control system in a hybrid vehicle. lf the combustion engine 2 iscontrolled to maintain the idling speed even when the engine shutdown isrequested, this is suitably indicated to the driver through a display or similar.
    The step to maintain as high temperature as possible in the waste heatrecovery system 4 when the combustion engine is not about to be shut downsuitably comprises to control the heat source 32 to bypass the evaporator 22 ifthe temperature of the heat source 32 is lower than the temperature of theevaporator 22. When the vehicle 1 is standing still the combustion engine 2 istypically operating with an idling speed. The temperature of the heat source 32associated with the combustion engine 2 is thereby lower than during normaloperation. By controlling the heat source 32 to bypass the evaporator 22 whenthe temperature is lower than the temperature of the evaporator 22 the heatsource 32 will not cool the evaporator 22. The temperature of the waste heatrecovery system 4 will thereby be maintained as high as possible. However, ifthe temperature of the heat source 32 is higher than the temperature of the28evaporator 22, the heat source 32 is suitably controlled to flow through theevaporator 22. This way, the heat source 32 will heat the evaporator 22 andthe temperature in the waste heat recovery system 4 will thereby bemaintained as high as possible.
    Figure 4 schematically illustrates a device 500. The control unit 40 and/orcomputer 42 described with reference to Figure 2 may in a version comprisethe device 500. The term “link” refers herein to a communication link whichmay be a 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 dataprocessing unit 510 and a read/write memory 550. The non-volatile memory520 has a first memory element 530 in which a computer program, e.g. anoperating system, is stored for controlling the function of the device 500. Thedevice 500 further comprises a bus controller, a serial communication port, I/Omeans, an A/D converter, a time and date input and transfer unit, an eventcounter and an interruption controller (not depicted). The non-volatile memory520 has also a second memory element 540.
    There is provided a computer program P which comprises routines for amethod for controlling the temperature of a waste heat recovery system 4according to the invention. The computer program P comprises routines foridentifying that a vehicle 1 comprising the vehicle system 10 is standing still.The computer program P comprises routines for determining if the combustionengine 2 is about to be shut down. The computer program P comprisesroutines for controlling the temperature in the waste heat recovery system 4based on whether the combustion engine 2 is about to be shut down or not.The computer program P comprises routines for controlling the temperature inthe waste heat recovery system 4 by controlling the heat source 32 associatedwith the combustion engine 2. The program P may be stored in an executableform or in a compressed form in a memory 560 and/or in a read/write memory550.29Where the data processing unit 510 is described as performing a certainfunction, it means that the data processing unit 510 effects a certain part of theprogram stored in the memory 560 or a certain part of the program stored inthe read/write memory 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 inthe second memory element 540. When input data received have beentemporarily stored, the data processing unit 510 is prepared to effect codeexecution as described 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 presentinvention is provided for i|ustrative and descriptive purposes. lt is not intendedto be exhaustive 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 explainthe principles of the invention and its practical applications and hence make itpossible for specialists to understand the invention for various embodimentsand with the various modifications appropriate to the intended use.
    权利要求:
    Claims (15)
    [1] 1. A method for controlling the temperature in a waste heat recovery system(4) associated with a combustion engine (2), the waste heat recovery system(4) comprising a working fluid circuit (20); at least one evaporator (22); anexpander (24); a condenser (26) and a pump (30) arranged to pump theworking fluid (WF) through the circuit (20), wherein the at least one evaporator(22) is arranged for heat exchange between the working fluid (WF) and a heatsource (32) associated with the combustion engine (2), wherein the condenser(26) of the waste heat recovery system (10) is connected to a coo|ing system(6) , characterized by the steps of: - determining (s101) if a combustion engine (2) associated with the waste heatrecovery system (4) is about to be shut down; and - controlling (s102) the temperature in the waste heat recovery system (4) based on whether the combustion engine (2) is about to be shut down or not.
    [2] 2. The method according to c|aim 1, wherein the step to control (s102) thetemperature in the waste heat recovery system (4) comprises to control the heat source (32) associated with the combustion engine (2).
    [3] 3. The method according to c|aim 1 or 2, wherein the step to control (s102) thetemperature in the waste heat recovery system (4) comprises to maintain ashigh temperature as possible, if the combustion engine is not about to be shut down.
    [4] 4. The method according to any of the preceding claims, wherein the step tocontrol (s102) the temperature in the waste heat recovery system (4)comprises to reduce the temperature prior to combustion engine shutdown, ifthe combustion engine is about to be shut down.
    [5] 5. The method according to c|aim 4, wherein the step to reduce the temperature in the waste heat recovery system (4) comprises to control the 31 heat source (32) to bypass the evaporator (22) if the temperature of the heat source (32) is higher than the temperature of the evaporator (22).
    [6] 6. The method according to c|aim 4 or 5, wherein the step to reduce thetemperature in the waste heat recovery system (4) comprises to control theheat source (32) to flow through the evaporator (22) if the temperature of theheat source (32) is lower than the temperature of the evaporator (22).
    [7] 7. The method according to any of c|aims 4-6, wherein the step to reduce thetemperature in the waste heat recovery system (4) comprises to increase theflow of cooling fluid (CF) in the cooling system (6) flowing through the condenser (26).
    [8] 8. The method according to any of c|aims 4-7, wherein the step to reduce thetemperature in the waste heat recovery system (4) comprises to increase theflow of working fluid (WF) through the circuit (20) of the waste heat recoverysystem (4).
    [9] 9. The method according to any of c|aims 4-8, wherein shutdown of thecombustion engine (2) is delayed until the temperature of the waste heat recovery system (4) is below a target temperature.
    [10] 10. The method according to c|aim 3, wherein the step to maintain as hightemperature as possible in the waste heat recovery system (4) comprises tocontrol the heat source (32) to bypass the evaporator (22) if the temperature of the heat source (32) is lower than the temperature of the evaporator (22).
    [11] 11. The method according to c|aim 3 or 10, wherein the step to maintain ashigh temperature as possible in the waste heat recovery system (4) comprises to control the heat source (32) to flow through the evaporator (22) if the 32 temperature of the heat source (32) is higher than the temperature of the evaporator (22).
    [12] 12. A waste heat recovery system (4) associated with a combustion engine (2),the waste heat recovery system (4) comprising a working fluid circuit (20); atleast one evaporator (22); an expander (24); a condenser (26) and a pump(30) arranged to pump the working fluid (WF) through the circuit (20), whereinthe at least one evaporator (22) is arranged for heat exchange between theworking fluid (WF) and a heat source (32) associated with the combustionengine (2), wherein the condenser (26) of the waste heat recovery system (10)is connected to a coo|ing system (6), characterized in that the waste heatrecovery system (4) comprises a control unit (40) adapted to determine if acombustion engine (2) associated with the waste heat recovery system (4) isabout to be shut down; and control the temperature in the waste heat recoverysystem (4) based on whether the combustion engine (2) is about to be shut down or not.
    [13] 13. A vehicle, characterized in that it comprises a waste heat recoverysystem (4) according claim 12.
    [14] 14. A computer program (P), wherein said computer program comprisesprogram code for causing an electronic control unit (40; 500) or a computer(42; 500) connected to the electronic control unit (40; 500) to perform the stepsaccording to any of the claims 1-11.
    [15] 15. A computer program product comprising a program code stored on acomputer-readable medium for performing the method steps according to anyof claims 1-11, when said computer program is run on an electronic control unit (40; 500) or a computer (42; 500) connected to the electronic control unit.
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    申请号 | 申请日 | 专利标题
    SE1650132A|SE539691C2|2016-02-04|2016-02-04|A method for controlling the temperature of a waste heat recovery system and such a waste heat recovery system|SE1650132A| SE539691C2|2016-02-04|2016-02-04|A method for controlling the temperature of a waste heat recovery system and such a waste heat recovery system|
    US16/072,835| US10662894B2|2016-02-04|2017-01-11|Method for controlling the temperature of a waste heat recovery system and such a waste heat recovery system|
    BR112018013898-3A| BR112018013898A2|2016-02-04|2017-01-11|method for controlling the temperature of a waste heat recovery system and a waste heat recovery system like this|
    PCT/SE2017/050018| WO2017135864A1|2016-02-04|2017-01-11|A method for controlling the temperature of a waste heat recovery system and such a waste heat recovery system|
    CN201780007901.5A| CN108495992B|2016-02-04|2017-01-11|Method for controlling the temperature of a waste heat recovery system and such a waste heat recovery system|
    KR1020187024066A| KR102116958B1|2016-02-04|2017-01-11|Method for controlling temperature of waste heat recovery system and such waste heat recovery system|
    EP17747865.8A| EP3411586B1|2016-02-04|2017-01-11|A method for controlling the temperature of a waste heat recovery system and such a waste heat recovery system|
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