(19)
(11)EP 2 603 673 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
25.12.2019 Bulletin 2019/52

(21)Application number: 11817165.1

(22)Date of filing:  13.08.2011
(51)Int. Cl.: 
F01K 25/02  (2006.01)
F01K 19/04  (2006.01)
F01K 13/02  (2006.01)
F01K 27/02  (2006.01)
F01K 23/10  (2006.01)
F01K 23/06  (2006.01)
(86)International application number:
PCT/US2011/047700
(87)International publication number:
WO 2012/021881 (16.02.2012 Gazette  2012/07)

(54)

RANKINE CYCLE CONDENSER PRESSURE CONTROL USING AN ENERGY CONVERSION DEVICE BYPASS VALVE

RANKINE-ZYKLUS-KONDENSATORDRUCKSTEUERUNG ÜBER EIN BYPASSVENTIL EINER ENERGIEUMWANDLUNGSVORRICHTUNG

RÉGULATION DE PRESSION DE CONDENSEUR À CYCLE DE RANKINE AU MOYEN D'UNE SOUPAPE DE DÉRIVATION DE DISPOSITIF DE CONVERSION D'ÉNERGIE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 13.08.2010 US 373657 P

(43)Date of publication of application:
19.06.2013 Bulletin 2013/25

(73)Proprietor: Cummins Intellectual Properties, Inc.
Minneapolis, Minnesota 55432 (US)

(72)Inventors:
  • ERNST, Timothy, C.
    Columbus Indiana 47203 (US)
  • NELSON, Christopher, R.
    Columbus Indiana 47203 (US)
  • ZIGAN, James, A.
    Versailles Indiana 47042 (US)

(74)Representative: Ridderbusch, Oliver 
Prisma IP Patentanwaltskanzlei Landshuter Allee 10
80637 München
80637 München (DE)


(56)References cited: : 
WO-A1-2008/106774
US-A1- 2004 107 700
US-A1- 2004 255 587
US-A1- 2009 241 543
JP-A- 60 222 511
US-A1- 2004 107 700
US-A1- 2009 151 356
US-A1- 2009 277 173
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] The inventions relate to a waste heat recovery system and method, and more particularly, to a system and method in which a parameter of a Rankine cycle is regulated.

    BACKGROUND



    [0002] A Rankine cycle (RC) can capture a portion of heat energy that normally would be wasted ("waste heat") and convert a portion of that captured heat energy into energy that can perform useful work or into some other form of energy. Systems utilizing an RC are sometimes called waste heat recovery (WHR) systems. Such a system is for example disclosed in document US2009/0241543. For example, heat from an internal combustion engine system such as exhaust gas heat energy and other engine heat sources (e.g., engine oil, exhaust gas, charge gas, water jackets) can be captured and converted to useful energy (e.g., electrical or mechanical energy). In this way, a portion of the waste heat energy can be recovered to increase the efficiency of a system including one or more waste heat sources.

    [0003] FIG. 1 shows an exemplary RC system 1 including a feed pump 10, a recuperator 12, a boiler/superheater (heat exchanger) 14, an energy conversion device 16 (e.g., expander, turbine etc.), a condenser 18, and a receiver 20. The path of the RC through and between these elements contains a working fluid that the feed pump 10 moves along the path and provides as a high pressure liquid to the recuperator 12 and heat exchanger 14. The recuperator 12 is a heat exchanger that increases the thermal efficiency of the RC by transferring heat to the working fluid along a first path, and at a different point of the RC along a second path, transfers heat from the working fluid. In the first path through the recuperator 12 from the pump 10 to the boiler/superheater 14, heat stored in the recuperator is transferred to the lower temperature working fluid, and the pre-heated working fluid next enters an inlet of the boiler/superheater 14. In the boiler/superheater 14, heat from a waste heat source associated with an internal combustion engine (not shown) (e.g., exhaust gases, engine water jackets, intake air, charge air, engine oil etc.) is transferred to the high pressure working fluid, which causes the working fluid to boil and produces a high pressure vapor that exits the boiler/superheater 14 and enters an inlet of the energy conversion device. While FIG. 1 shows only a single boiler/superheater 14, more than one heat exchanger can be supplied in parallel or in series to more than one heat source associated with the engine.

    [0004] The pressure and temperature of the working fluid vapor drop as the fluid moves across the energy conversion device, such as a turbine, to produce work. For example, the RC system 1 can include turbine as the energy conversion device 16 that rotates as a result of the expanding working fluid vapor. The turbine can, in turn, cause rotation of an electric generator (not shown). The electric power generated by the generator can be fed into a driveline motor generator (DMG) via power electronics (not shown). A turbine can be configured to alternatively or additionally drive some mechanical element to produce mechanical power. The additional converted energy can be transferred to the engine crankshaft mechanically or electrically, or used to power parasitics and/or storage batteries. Alternatively, the energy conversion device can be adapted to transfer energy from the RC system 1 to another system (e.g., to transfer heat energy from the RC system 1 to a fluid for a heating system). The gases exit the outlet of the energy conversion device, for example, expanded gases exiting the outlet of the turbine 16, and are then cooled and condensed via a condenser 18, which is cooled by a low temperature source (LTS) cooling medium, for example, a liquid cooling loop (circuit) including a condenser cooler having RAM airflow and condenser cooler pump (not shown) to move the cooling medium (e.g., glycol, water etc.) in the cooling loop, although other condenser cooling schemes can be employed such as a direct air-cooled heat exchanger.

    [0005] The expanded working fluid vapors and liquid exiting the outlet of the turbine 16 is provided along the second path through the recuperator 12, where heat is transferred from the working fluid to be stored in the recuperator 12 before entering the condenser 18. The condenser 18 contains one or more passageways though which the working fluid vapors and liquid moves that are cooled by a cooling medium, such as a coolant or air, to cool and condense the working fluid vapors and liquid. The condensed working fluid is provided as a liquid to a receiver vessel 20 where it accumulates before moving to the feed pump 10 to complete the cycle.

    [0006] The RC working fluid can be a non-organic or an organic working fluid. Some examples of working fluid are Genetron ™ R-245fa from Honeywell, Therminol ™, Dowtherm J from the Dow Chemical Co., Fluorinol, Toluene, dodecane, isododecane, methylundecane, neopentane, neopentane, octane, water/methanol mixtures, or steam. US 2009/0241561 A1 describes a system for converting heat from an engine into work, including a turbine that transforms the heat into work, a condenser that transforms the working fluid into liquid, a recuperator that routes working fluid from the turbine to the condenser, and a recuperator bypass. JP S 60222511 A describes a cycle to convert energy of a heat source, wherein a bypass valve is used to bypass a turbine.

    SUMMARY



    [0007] The invention provides a waste heat recovery (WHR) system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system.

    [0008] In an embodiment, a system for recovering waste heat from an internal combustion engine using a Rankine cycle (RC) system includes a heat exchanger thermally coupled to a heat source associated with the internal combustion engine and adapted to transfer heat from the heat source to working fluid of the RC system, an energy conversion device fluidly coupled to the heat exchanger and adapted to receive the working fluid having the transferred heat and convert the energy of the transferred heat, a condenser fluidly coupled to the energy conversion device and adapted to receive the working fluid from which the energy was converted, and a pump positioned in a flow path of the working fluid between the condenser and the heat exchanger and adapted to move the working fluid through the RC system. The RC system includes a bypass valve having an inlet fluidly connected between an outlet of the heat exchanger and an inlet of the energy conversion device, and an outlet fluidly connected to an inlet of the condenser. At least one sensor is positioned in the flow path of the working fluid between the condenser and the pump and adapted to sense pressure and temperature characteristics of the working fluid and generate a signal indicative of the temperature and pressure of the working fluid. The RC system includes a controller adapted to regulate the condenser pressure in the RC system via controlling the bypass valve based on the generated signal.

    [0009] In another embodiment, a method is provided for regulating pressure of a working fluid in a Rankine cycle (RC) system that includes a working fluid path through a heat exchanger thermally coupled to a heat source of an internal combustion engine, through an energy conversion device in the working fluid path downstream of the heat exchanger, through a condenser in the working fluid path downstream of the energy conversion device, and through a pump in the working fluid path between the condenser and the heat exchanger. The method includes sensing the temperature and pressure of the working fluid in the working fluid path between the condenser and the pump, and if the sensed pressure of the working fluid is less than a saturation pressure of the working fluid at the monitored temperature, increasing the pressure of the working fluid in the condenser by diverting at least some of the working fluid in the working fluid path upstream of an inlet of the energy conversion device to an inlet of the condenser to bypass the energy conversion device.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0010] 

    FIG. 1 is a diagram of an exemplary RC system of a WHR system.

    FIG. 2 is a diagram of an exemplary RC system of a WHR system including an energy conversion device and recuperator bypass valve in accordance with an exemplary embodiment.

    FIG. 3 shows is a flow diagram of a process for regulating pressure of a working fluid in a condenser of a Rankine cycle (RC) in accordance with an exemplary embodiment.


    DETAILED DESCRIPTION



    [0011] The inventors have recognized that cavitation of the feed pump 10 must be overcome for efficient operation of the Rankine cycle, especially an ORC. Cavitation can result from rapid condenser pressure changes due to large engine transients or changes in condenser coolant temperature (or air temperature). The fluid in the receiver 20 can boil if the condenser pressure drops rapidly causing the feed pump 10 to cavitate when the working fluid is at saturated conditions.

    [0012] FIG. 2 is a diagram of an exemplary RC system 2 that includes modifications of the RC 1 shown in FIG. 1. Elements having the same reference number as shown in FIG. 1 are described above. The RC system 2 includes a bypass valve 22 that can route, or divert at least some of the RC working fluid at high pressure around energy conversion device 16, and also around recuperator 12 to place additional heat load on the condenser 18 when needed during transients. Both the energy conversion device 16 and recuperator 12 remove energy from the refrigerant vapor (i.e., the RC working fluid vapor). By bypassing the energy conversion device 16 and recuperator 12, the working fluid will enter the condenser 18 at a higher temperature, and therefore a higher energy state compared with an RC system 1 in which all vaporized working fluid flows through the turbine and recuperator prior to the condenser 18. The condenser pressure is a function of the heat rejection required from it, namely, higher heat rejection requirements cause the pressure (and therefore temperature) to increase. The higher condenser temperature results in a greater temperature difference to the cooling medium (e.g., air or coolant). Since the receiver 20 is fluidly connected to the condenser 18 at approximately the same pressure as the condenser 18, the cavitation margin for the fluid in the receiver 20 is increased as pressure is increased. This prevents the feed pump 10 from losing its prime and enables the feed pump 10 to be more capable of pumping the working fluid required for cooling. Opening the turbine/recuperator bypass valve 22 also reduces the high-side pressure which reduces the pumping requirement of the feed pump 10 by reducing a required pressure rise.

    [0013] As shown in FIG. 2, the RC system 2 includes a control module 24 adapted to control the energy conversion device/recuperator bypass valve 22 in either a proportional or binary manner to regulate the condenser pressure in the Rankine cycle. Sensor module 26, which is adapted to sense a pressure characteristic and a temperature characteristic of the working fluid, is provided in the path of the working fluid between the condenser and the feed pump 10 and generates a signal that is provided on communication path 28 (e.g., one or more wired or wireless communication channels). Although FIG. 2 shows only one module 26, it is to be understood that separate sensing devices can be utilized to sense temperature and pressure characteristics of the working fluid, and that these sensors can be provided at positions downstream of the condenser 18 other than that depicted. The control module 24 receives a pressure signal P and a temperature signal T from sensor module 26 and continuously or periodically monitors the pressure P and temperature T of the working fluid. From the monitored values of P and T, the controller determines whether a low pressure state exists (e.g., during a transient condition) and whether the bypass valve 22 should be opened. In an embodiment, a low pressure state is a state in which the working fluid is at or near a boiling point, i.e., the P when at or near the saturation pressure, PWF, saturation for a sensed T, and if the controller determines this state exists, it provides a signal on communication path 29 causing the bypass valve 22 to open.

    [0014] FIG. 3 is a process flow diagram of an exemplary method 30 that can be performed by controller 24 in an RC system 2 to determine when to open or close the bypass valve 22. With reference to FIGS. 2 and 3, in process 32 the controller 24 monitors temperature T and pressure P characteristics of the working fluid (WF) sensed downstream of the condenser 18. In decision 34, the controller 24 determines whether the sensed pressure P of the WF is greater than a saturation pressure of corresponding to the sensed T), i.e., if P > PWF, saturation. If the sensed P corresponds to a pressure value less than PWF, saturation, the "NO" path is take from decision 34 to process 36 in which the bypass valve 22 across a recuperator 12 and/or an energy conversion device (e.g., a turbine) 16 of the RC system is opened to increase WF pressure in a condenser 18 of the RC system 2. After performing process 36, method 30 returns to the process 32 to continue monitoring the temperature and pressure of the WF. If the controller 24 determines that the sensed P corresponds to a pressure value greater than PWF, saturation, the "YES" path is take from decision 34 to process decision 38, which determines the present state of the bypass valve 22. If the controller 24 determines that the present state of bypass valve 22 is open, the "YES" path is taken to process 40, which closes the bypass valve 22. If the present state determined by controller 24 in decision 38 indicates that the bypass valve 22 is closed, the "NO" path is taken from decision 38, and the bypass valve 22 remains closed. After either case (i.e., leaving the valve 22 closed or closing it), the method returns to process 32 and the controller 24 continues to monitor the pressure P and temperature T of the WF. It is to be appreciated that other embodiments can include more granular control of the extent that the bypass valve 22 is opened, for example, based on a load prediction algorithm, operating mode, sensed transient condition, and so on.

    [0015] Control of the bypass valve 22 can be accomplished using an actuator controlled by a controller, for example, controller 24 or another controller communicating with controller 24, to open the valve 22 based on the generated signal. The controller can, via communication path 29, instruct valve 22 to open entirely, or as pointed out above, to an extent based on the magnitude of the transient condition. The controller 24 can determine, for example, from a lookup table, map or mathematical relation, what minimum pressure for a monitored temperature must be maintained and then control the pressure of the working fluid in the condenser via operation of the bypass valve 22 to prevent cavitation in the feed pump 10.

    [0016] The control module 24 can be, for example, an electronic control unit (ECU) or electronic control module (ECM) that monitors the performance of the engine (not shown) and other elements of a vehicle. The control module 24 can be a single unit or plural control units that collectively perform these monitoring and control functions of the engine and condenser coolant system. The control module 24 can be provided separate from the coolant systems and communicate electrically with systems via one or more data and/or power paths. The control module 24 can also utilize sensors, such as pressure, temperature sensors in addition to the sensors 26 to monitor the system components and determine whether the these systems are functioning properly. The control module 24 can generate control signals based on information provided by sensors described herein and perhaps other information, for example, stored in a database or memory integral with or separate from the control module 24.

    [0017] The control module 24 can include a processor and modules in the form of software or routines that are stored on computer readable media such as memory (e.g., read-only memory, flash memory etc.), which is executable by the processor of the control module. For example, instructions for carrying out the processes shown in FIG. 3 can be stored with the control module 24 or stored elsewhere, but accessible by the control module 24. In alternative embodiments, modules of control module 24 can include electronic circuits (i.e., hardware) for performing some or all or part of the processing, including analog and/or digital circuitry. These modules can comprise a combination of software, electronic circuits and microprocessor based components. The control module 24 can be an application specific module or it can receive data indicative of engine performance and exhaust gas composition including, but not limited to any of engine position sensor data, speed sensor data, exhaust mass flow sensor data, fuel rate data, pressure sensor data, temperature sensor data from locations throughout the engine and an exhaust aftertreatment system, data regarding requested power, and other data. The control module can then generate control signals and output these signals to control elements of the RC, the engine, the aftertreatment system, and/or other systems and devices associated with a vehicle.

    [0018] Accordingly, a bypass valve can be controlled to bypass (or divert) hot vapor around a recuperator and/or an energy conversion device of an RC system to increase the internal energy of the fluid entering the RC system condenser, and therefore increase the pressure of the working fluid in the condenser (and receiver pressure). The increased condenser and receiver pressure is beneficial during extreme transient operation of the system because it reduces the likelihood of the feed pump losing its prime by increasing the fluid's cavitation margin. This facilitates working fluid pumping without cavitation, which facilitates achieving emission-critical cooling of EGR gases and a decrease of wear on the feed pump.

    [0019] While the above embodiment is described as including a recuperator (heat exchanger), other embodiments consistent with the disclosure can be configured across the energy conversion device without a recuperator. Additionally, an embodiment of an RC system can be configured without a receiver between the condenser and the feed pump. Furthermore, the bypass valve can be used as a load limiting device for an expander (e.g., a turbine).

    [0020] Embodiments of the disclosed RC system condenser pressure regulation using a bypass valve to bypass the recuperator and/or energy conversion device can be applied to any type of internal combustion engine (e.g., diesel or gasoline engines) and can provide a large improvement in fuel economy and aid in the operation of RC system during transient engine cycles (e.g., in mobile on-highway vehicle applications) and/or rapidly changing temperatures.


    Claims

    1. A system for recovering waste heat from an internal combustion engine using a Rankine cycle (RC) system (1), comprising:

    a heat exchanger (14) thermally coupled to a heat source associated with the internal combustion engine and adapted to transfer heat from the heat source to working fluid of the RC system (1);

    an energy conversion device (16) fluidly coupled to the heat exchanger (14) and adapted to receive the working fluid having the transferred heat and convert the energy of the transferred heat;

    a condenser (18) fluidly coupled to the energy conversion device (16) and adapted to receive the working fluid from which the energy was converted;

    a pump (10) positioned in a flow path of the working fluid between the condenser (18) and the heat exchanger (14), said pump (10) adapted to move the working fluid through the RC system (1);

    a bypass valve (22) having an inlet fluidly connected between an outlet of the heat exchanger (14) and an inlet of the energy conversion device (16), and an outlet fluidly connected to an inlet of the condenser (18);

    at least one sensor (26) in the flow path of the working fluid between the condenser (18) and the pump (10) and adapted to sense pressure and temperature characteristics of the working fluid and to generate a signal indicative of the temperature and pressure of the working fluid, the at least one sensor (26) being configured to sense a transient condition; and

    a controller (24) adapted to regulate the condenser (18) pressure in the RC system (1) via controlling the bypass valve (22) based on the generated signal and adapted to control an extent to which the bypass valve (22) is opened based on a magnitude of the sensed transient condition.


     
    2. The system of claim 1, wherein the controller (24) is adapted to determine whether the pressure of the working fluid in the flow path is greater than a saturation pressure of the working fluid for the sensed temperature.
     
    3. The system of claim 1, wherein the RC system (1) includes a recuperator (12) having an inlet fluidly coupled to the outlet of the energy conversion device (16) and an outlet fluidly coupled to said outlet of said bypass valve (22).
     
    4. The waste heat recovery system of claim 1, wherein said energy conversions device is a turbine, and said RC system (1) further comprises a recuperator (12) having a first path fluidly connected between an outlet of the pump (10) and an inlet of the heat exchanger (14), and a second path fluidly coupled between an outlet of the energy conversion device (16) and the inlet of the condenser (18), wherein the outlet of the bypass valve (22) is connected between the inlet of the condenser (18) and an outlet of the second path of the recuperator (12).
     
    5. A method of regulating pressure of a working fluid in a Rankine cycle (RC) system (1) including a working fluid path through a heat exchanger (14) thermally coupled to a heat source of an internal combustion engine, through an energy conversion device (16) in the working fluid path downstream of the heat exchanger (14), through a condenser (18) in the working fluid path downstream of the energy conversion device (16), and through a pump (10) in the working fluid path between the condenser (18) and the heat exchanger (14), the method comprising:

    sensing a transient condition, the temperature and pressure of the working fluid in the working fluid path between the condenser (18) and the pump (10),

    if the sensed pressure of the working fluid is less than a saturation pressure of the working fluid at the sensed temperature, increasing the pressure of the working fluid in the condenser (18) by diverting at least some of the working fluid in the working fluid path upstream of an inlet of the energy conversion device (16) to an inlet of the condenser (18) to bypass the energy conversion device (16), wherein an extent to which a bypass valve (22) is opened is controlled based on a magnitude of the sensed transient condition.


     
    6. The method of clam 5, wherein the RC system (1) further includes a recuperator (12) having an inlet fluidly coupled to the outlet of the energy conversion device (16) and an outlet fluidly coupled to an inlet of the condenser (18), and said diverted working fluid bypasses said recuperator (12).
     


    Ansprüche

    1. System zur Nutzung von Abwärme von einem Verbrennungsmotor unter Verwendung eines Rankine-Kreislauf- (RC) Systems (1), umfassend:

    einen Wärmetauscher (14), der thermisch mit einer Wärmequelle gekoppelt ist, die mit dem Verbrennungsmotor assoziiert und eingerichtet ist zum Übertragen von Wärme von der Wärmequelle zu Arbeitsfluid des RC-Systems (1);

    eine Energieumwandlungsvorrichtung (16), die fluidisch gekoppelt ist mit dem Wärmetauscher (14) und eingerichtet ist zum Empfangen des Arbeitsfluids, dem Wärme übertagen wurde, und Umwandeln der Energie der übertragenen Wärme;

    einen Kondensor (18), der fluidisch gekoppelt ist mit der Energieumwandlungsvorrichtung (16) und eingerichtet ist zum Empfanges des Arbeitsfluids, von dem die Energie umgewandelt wurde;

    eine Pumpe (10), die in einem Strömungspfad des Arbeitsfluids zwischen dem Kondensor (18) und dem Wärmetauscher (14) positioniert ist, wobei die besagte Pumpe (10) eingerichtet ist zum Befördern des Arbeitsfluids durch das RC-System (1);

    ein Umgehungsventil (22), das einen Einlass hat, welcher fluidisch zwischen einem Auslass des Wärmetauschers (14) und einem Einlass der Energieumwandlungsvorrichtung (16) verbunden ist, und das einen Auslass hat, welcher mit einem Einlass des Kondensors (18) fluidisch verbunden ist;

    mindestens ein Sensor (26) in dem Strömungspfad des Arbeitsfluids zwischen dem Kondensor (18) und der Pumpe (10), welcher eingerichtet ist zum Messen von Druck- und Temperaturcharakteristiken des Arbeitsfluids und zum Erzeugen eines Signals, das die Temperatur und den Druck des Arbeitsfluids angibt, wobei der mindestens eine Sensor (26) eingerichtet ist zum Messen einer transienten Bedingung; und

    ein Steuergerät (24), das eingerichtet ist zum Regulieren des Drucks des Kondensors (18) in dem RC-System (1) über Steuern des Umgehungsventils (22) basierend auf dem erzeugten Signal und das eingerichtet ist zum Steuern eines Ausmaßes, zu welchem das Umgehungsventil (22) geöffnet wird, basierend auf einer Größe der gemessenen transienten Bedingung.


     
    2. Das System nach Anspruch 1, wobei das Steuergerät (24) eingerichtet ist zum Bestimmen, ob der Druck des Arbeitsfluids in dem Strömungspfad größer ist als ein Sättigungsdruck des Arbeitsfluids für die gemessene Temperatur.
     
    3. Das System nach Anspruch 1, wobei das RC-System (1) einen Rekuperator (12) enthält, der einen Einlass hat, welcher mit dem Auslass der Energieumwandlungsvorrichtung (16) fluidisch gekoppelt ist, und der einen Auslass hat, welcher mit dem besagten Auslass des besagten Umgehungsventils (22) fluidisch gekoppelt ist.
     
    4. Das Abwärmenutzungssystem nach Anspruch 1, wobei die besagte Energieumwandlungsvorrichtung eine Turbine ist, und das besagte RC-System (1) außerdem einen Rekuperator (12) umfasst, der einen ersten Pfad hat, welcher zwischen einem Auslass der Pumpe (10) und einem Einlass des Wärmetauschers (14) fluidisch verbunden ist, und einen zweiten Pfad, der zwischen einem Auslass der Energieumwandlungsvorrichtung (16) und dem Einlass des Kondensors (18) fluidisch gekoppelt ist, wobei der Auslass des Umgehungsventils (22) zwischen dem Einlass des Kondensors (18) und einem Auslass des zweiten Pfads des Rekuperators (12) verbunden ist.
     
    5. Verfahren zum Regulieren von Druck eines Arbeitsfluids in einem Rankinekreislauf- (RC) Systems (1), umfassend einen Arbeitsfluidpfad durch einen Wärmetauscher (14), der thermisch gekoppelt ist mit einer Wärmequelle eines Verbrennungsmotors, durch eine Energieumwandlungsvorrichtung (16) in dem Arbeitsfluidpfad stromabwärts von dem Wärmetauscher (14), durch einen Kondensor (18) in dem Arbeitsfluidpfad stromabwärts von der Energieumwandlungsvorrichtung (16), und durch eine Pumpe (10) in dem Arbeitsfluidpfad zwischen dem Kondensor (18) und dem Wärmetauscher (14), wobei das Verfahren umfasst:

    Messen einer transienten Bedingung, der Temperatur und des Drucks des Arbeitsfluids in dem Arbeitsfluidpfad zwischen dem Kondensor (18) und der Pumpe (10);

    wenn der gemessene Druck des Arbeitsfluids kleiner ist als ein Sättigungsdruck des Arbeitsfluids bei der gemessenen Temperatur: Erhöhen des Drucks des Arbeitsfluids in dem Kondensor (18) durch Umlenken von mindestens einem Teil des Arbeitsfluids in dem Arbeitsfluidpfad stromaufwärts von einem Einlass der Energieumwandlungsvorrichtung (16) zu einem Einlass des Kondensors (18), um die Energieumwandlungsvorrichtung (16) zu umgehen, wobei ein Ausmaß, zu welchem ein Umgehungsventil (22) geöffnet wird, basierend auf einer Größe der gemessenen transienten Bedingung gesteuert wird.


     
    6. Das Verfahren nach Anspruch 5, wobei das RC-System (1) außerdem einen Rekuperator (12) enthält, der einen Einlass hat, welcher mit dem Auslass der Energieumwandlungsvorrichtung (16) fluidisch gekoppelt ist, und der einen Auslass hat, welcher mit einem Einlass des Kondensors (18) fluidisch gekoppelt ist, und das besagte umgelenkte Arbeitsfluid den besagten Rekuperator (12) umgeht.
     


    Revendications

    1. Un système pour la récupération de la chaleur résiduelle d'un moteur à combustion interne en utilisant un système de cycle de Rankine (RC) (1), comprenant :

    un échangeur de chaleur (14) thermiquement couplé à une source de chaleur associée au moteur à combustion interne et adaptée pour transférer de la chaleur de la source de chaleur à un fluide de travail du système RC (1),

    un dispositif de conversion d'énergie (16) couplé fluidiquement à l'échangeur de chaleur (14) et adapté pour recevoir le fluide de travail ayant reçu la chaleur transférée et convertir l'énergie de la chaleur transférée,

    un condenseur (18) fluidiquement couplé au dispositif de conversion d'énergie (16) et adapté pour recevoir le fluide de travail à partir duquel l'énergie a été convertie,

    une pompe (10) positionnée dans une voie d'écoulement du fluide de travail entre le condenseur (18) et l'échangeur de chaleur (14), ladite pompe (10) étant adaptée pour déplacer le fluide de travail au travers du système RC (1),

    une soupape de dérivation (22) ayant une entrée fluidiquement connectée entre une sortie de l'échangeur de chaleur (14) et une entrée du dispositif de conversion d'énergie (16) et ayant une sortie fluidiquement connectée à une entrée du condenseur (18),

    au moins un capteur (26) dans la voie d'écoulement du fluide de travail entre le condenseur (18) et la pompe (10), lequel est adapté pour mesurer des caractéristiques de pression et de température du fluide de travail et pour générer un signal indiquant la température et la pression du fluide de travail, le au moins un capteur (26) étant configuré pour mesurer une condition transitoire, et

    un appareil de contrôle (24) adapté pour réguler la pression du condenseur (18) dans le système RC (1) en contrôlant la soupape de dérivation (22) sur la base du signal généré et adapté pour contrôler dans quelle mesure la soupape de dérivation (22) est ouverte sur la base d'une taille de la condition transitoire mesurée.


     
    2. Le système selon la revendication 1, tandis que l'appareil de contrôle (24) est adapté pour déterminer si la pression du fluide de travail dans la voie d'écoulement est plus élevée qu'une pression de saturation du fluide de travail pour la température mesurée.
     
    3. Le système selon la revendication 1, tandis que le système RC (1) inclut un récupérateur (12) ayant une entrée fluidiquement couplée à la sortie du dispositif de conversion d'énergie (16) et une sortie fluidiquement couplée à ladite sortie de ladite soupape de dérivation (22).
     
    4. Le système de récupération de la chaleur résiduelle selon la revendication 1, ledit dispositif de conversion d'énergie étant une turbine et ledit système RC (1) comprenant également un récupérateur (12) ayant une première voie fluidiquement connectée entre une sortie de la pompe (10) et une entrée de l'échangeur de chaleur (14) ainsi qu'une deuxième voie fluidiquement couplée entre une sortie du dispositif de conversion d'énergie (16) et l'entrée du condenseur (18), tandis que la sortie de la soupape de dérivation (22) est connectée entre l'entrée du condenseur (18) et une sortie de la deuxième voie du récupérateur (12).
     
    5. Procédé pour réguler la pression d'un fluide de travail dans un système de cycle de Rankine (RC) (1) comprenant une voie de fluide de travail au travers d'un échangeur de chaleur (14) thermiquement couplé à une source de chaleur d'un moteur à combustion interne, au travers d'un dispositif de conversion d'énergie (16) dans la voie de fluide de travail en aval de l'échangeur de chaleur (14), au travers d'un condenseur (18) dans la voie de fluide de travail en aval du dispositif de conversion d'énergie (16) et au travers d'une pompe (10) dans la voie de fluide de travail entre le condenseur (18) et l'échangeur de chaleur (14), le procédé comprenant :

    la mesure d'une condition transitoire, de la température et de la pression du fluide de travail dans la voie de fluide de travail entre le condenseur (18) et la pompe (10),

    lorsque la pression mesurée du fluide de travail est inférieure à une pression de saturation du fluide de travail à la température mesurée : l'augmentation de la pression du fluide de travail dans le condenseur (18) en détournant au moins une partie du fluide de travail dans la voie de fluide de travail en amont d'une entrée du dispositif de conversion d'énergie (16) vers une entrée du condenseur (18) pour contourner le dispositif de conversion d'énergie (16), tandis que la mesure dans laquelle une soupape de dérivation (22) est ouverte est contrôlée sur la base d'une taille de la condition transitoire mesurée.


     
    6. Le procédé de la revendication 5, tandis que le système RC (1) comprend également un récupérateur (12) ayant une entrée fluidiquement couplée à la sortie du dispositif de conversion d'énergie (16) et une sortie fluidiquement couplée à une entrée du condenseur (18), et tandis que le fluide de travail détourné contourne ledit récupérateur (12).
     




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    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description