• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates an arrangement for recovering heat energy in exhaust gases from a combustion engine (2). The arrangement comprises a WHR system comprising a WHR circuit (18) with a circulating working medium, a first heat exchanger (20) in the form of an evaporator arranged at the high pressure side (18a) of the WHR circuit (18) in which the working medium is heated by exhaust gases from the combustion engine (2), and an expander (22) generating mechanical energy from the working medium. The WHR system comprises a second heat exchanger (21) arranged on the high pressure side (18a) of the WHR circuit (18) having at least twice the heat storage capacity as the first heat exchanger (20) and a valve device (24-27, 19) configured to direct exhaust gases and working medium to the heat exchangers (20, 21) in a manner such that the working medium is evaporated and superheated in at least one of said heat exchanger (20, 21) before it is directed to the expander (2).
    公开号:SE1651010A1
    申请号:SE1651010
    申请日:2016-07-07
    公开日:2018-01-08
    发明作者:Kardos Zoltan；Hall Ola
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    An arrangement for recovering heat energy in exhaust gases from a combustion engine BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to an arrangement for recovering heat energy in exhaust gases from a combustion engine according to the preamble of claim l.
    A WHR system (Waste Heat Recovery System) can be used for recovering Wastethermal energy and convert it to mechanical energy or electric energy. A WHR systemincludes a pump Which pressurizes and circulates a Working medium in a closedcircuit. The circuit comprises an evaporator Where the Working medium is heated andevaporated by a heat source such as, for example, eXhaust gases. The pressurized andheated gaseous Working medium expands in an expander. The expander generatesmechanical energy Which can be used to support the engine and/or apparatuses in avehicle. Alternatively, the expander is connected to a generator generating electricenergy. The fuel consumption of a combustion engine can be reduced by means of aWHR-system. However, the Waste heat energy can generally only be used at the time itis generated in case the WHR system does not comprise expensive equipmentconverting the heat energy to electrical energy. During certain operating conditions,there is more heat energy in the exhaust gases than can be utilized by the WHR system.During other operating conditions, there is substantially no heat energy in the eXhaustgases that can be utilized by the WHR system.
    WO 2014/096892 shows an engine arrangement comprising an internal combustionengine, a Waste heat recovery system in Which a Working fluid is successively pumpedby a pump, heated in a heat exchanger by means of a heat source produced by theengine operation, and expanded in an expander. The Waste heat recovery systemfurther comprises a heat storage device Which is arranged outside from the heatexchanger, downstream from the pump and upstream from the expander, said heatstorage device comprising a heat storage material Which is in thermal contact With theWorking fluid through a partition Wall and being arranged so as to be capable of storingheat from the heat source and of releasing previously stored heat in order to heat the Working fluid.
    SUMMARY OF THE INVENTION The object of the present invention is to provide an arrangement Which is substantiallyalways able to recover heat energy from eXhaust gases to mechanical energy When there is a power demand.
    The above mentioned object is achieved by the control system according to thecharacterizing part of claim l. The arrangement comprises a WHR system designedWith a first heat eXchanger and a second heat exchanger having a considerably higherheat storage capacity than the first heat eXchanger on its high pressure side. Preferably,the second heat eXchanger have a heat storage capacity of at least five times or tentimes the heat storing capacity of the first heat exchanger. The amount of heat energyin the eXhaust gases is related to the load of the combustion engine. Advantageously,the WHR system is designed to make use of all heat energy in the eXhaust gases atnormal load of the combustion engine. ln this case, the valve device directs the entireeXhaust gas floW and the Working medium to the first heat eXchanger for evaporation and superheating of the Working medium before it is directed to the eXpander.
    At a high load of the combustion engine, the WHR system is not able to recover allheat energy in the eXhaust gases to mechanical energy. ln this case and When there is apoWer demand of the WHR system, the valve device directs eXhaust gases andWorking medium to the first heat exchanger and the second heat eXchanger in a mannersuch that the WHR system recovers a part of the heat energy in the eXhaust gases tomechanical energy in accordance With its capacity at the same time as an eXceeded partof the heat energy in the eXhaust gases is used to heat the second heat eXchanger. At aloW load of the combustion engine, the valve device may directs the entire eXhaust gasfloW and the Working medium to the second heat eXchanger for evaporation andsuperheating of the Working medium. At a load of the combustion engine When there isno poWer demand, the valve device may directs the entire eXhaust gas floW to the second heat eXchanger in order to heat it to a higher temperature.
    Consequently, the above mentioned arrangement makes it possible to recover at least apart of the heat energy in the eXhaust gases to mechanical energy and to store anexceeded part of the heat energy in the second heat eXchanger. The heat energy storedin the second heat eXchanger can be used When the load on the combustion engine is loW at the same time as it is a poWer demand. Since the heat energy is stored in a heat exchanger, it is easy to utilize the stored heat energy. Furthermore, the WHR systemcan be given smaller dimensions than a corresponding conventional WHR system due to its ability to store heat energy in the second heat exchanger.
    According to an embodiment of the invention, the second heat exchanger has a largermass than the first heat exchanger. The capacity of a material body to store heat energyis related to the mass of the body. Thus, it is suitable that the second heat exchangerhas a considerably larger mass than the first heat exchanger. The second heatexchanger may comprises a solid material heated by the exhaust gases. Such a solidmaterial may, for example, be a ceramic material. Altematively or in combination.The second heat exchanger comprises a phase changing material. A lot of heat energycan be transferred between the exhaust gases and such a material during a phasechanging process. A second heat exchanger including a phase changing material doesnot need to be considerably heavier than the first heat exchanger. Furthermore, asecond heat exchanger provided with a phase changing material has a substantiallyconstant temperature during the phase changing process of the material. The phasechanging material, for example, be tin or zinc. According to a further altemative, thesecond heat exchanger may comprises a rr1ix of two phase changing materials. In thiscase, the second heat exchanger can be defined as a heat energy storage having two different temperature levels.
    According to an embodiment of the invention, the first heat exchanger and the secondheat exchanger are arranged in parallel in the WHR system and that the valve devicecomprises a valve directing the working medium flow to the first heat exchanger or thesecond heat exchanger. The valve may be configured to direct the working medium tothe first heat exchanger at normal and high load of the combustion engine when thereis a power demand of the WHR system. The valve may be configured to direct theworking medium to the second heat exchanger at low load when there is a powerdemand of the WHR system.
    According to an embodiment of the invention, the first heat exchanger and the secondheat exchanger are arranged in series in WHR system and that the valve devicecomprises a valve arranged in a downstream position of the first heat exchanger and anupstream position of the second heat exchanger. In case the first heat exchanger andthe second heat exchanger are arranged in an exhaust line of the combustion engine, the valve is configured to direct the working medium from the first heat exchanger past the second heat eXchanger at normal and high load of the combustion engine whenthere is a power demand of the WHR system. The valve is configured to direct theworking medium from the first heat exchanger to the second heat eXchanger at low load when there is a power demand of the WHR system.
    On the other hand, in case the first heat eXchanger is arranged in an eXhaust line of thecombustion engine and the second heat eXchanger are arranged outside the eXhaust lineof the combustion engine, the valve is configured to direct the working medium fromthe first heat eXchanger past the second heat exchanger at normal load of thecombustion engine when there is a power demand of the WHR system. The valve isconfigured to direct the working medium from the first heat eXchanger to the secondheat eXchanger at low load and at high load when there is a power demand of the WHRsystem. When there is a high load on the combustion engine, the working medium issuperheated to a too high temperature in the first heat eXchanger. ln this case, theworking medium is de- superheated in the second heat eXchanger. When there is a lowload on the combustion engine, the working medium may be evaporated and superheated in the second heat eXchanger.
    According to an embodiment of the invention, the arrangement comprises first heateXchanger bypass line and the valve device comprises at least one valve controlling theeXhaust gas flow through the first heat eXchanger and the first heat eXchanger bypassline. ln this case, it is possible to provide a reduced exhaust gas flow to the first heateXchanger during operating conditions when there is a high load on the combustionengine in order to provide a too high superheating of the working medium in the firstheat eXchanger. The exhaust gases in the bypass line can be used to heat the secondheat eXchanger. Furthermore, it is possible to direct the entire eXhaust gas flow via thefirst eXchanger bypass line when there is no heat transfer in the first heat exchanger in order to reduce the flow resistance for the eXhaust gases in the eXhaust line.
    According to an embodiment of the invention, the arrangement comprises a secondheat eXchanger bypass line and the valve device comprises at least one valvecontrolling the eXhaust gas flow through the second heat eXchanger and the secondheat eXchanger bypass line. The valve makes it possible to direct the eXhaust gas flowto the second heat eXchanger when it has a temperature high enough to heat the secondheat eXchanger and to the second eXchanger bypass line when it has a too low temperature to heat the second heat eXchanger.
    According to an embodiment of the invention, it comprises a control unit configured tocontrol the Valve device by means of information from at least one operatingparameter. Said operating parameter may be related to at least one of the followingparameters the temperature of the eXhaust gases, the temperature of the second heateXchanger, the load of the combustion engine and the power demand of the WHRsystem. The temperature difference between the eXhaust gases and the second heateXchanger, can be used to determine if it is possible to heat the second heat eXchangerby means of the eXhaust gases. The load of the combustion engine is related to theexhaust gas flow and the temperature of the eXhaust gases which define the heat energy in the eXhaust gases.
    BRIEF DESCRIPTION OF THE DRAVVINGS In the following preferred embodiments of the invention are described, as examples, with reference to the attached drawings, in which: Fig. l shows an arrangement according to a first embodiment of the invention, Fig. 2 shows an arrangement according to a second embodiment of theinvention and Fig. 3 shows an arrangement according to a third embodiment of the invention, DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THEINVENTION Fig. l shows a schematically disclosed vehicle l powered by a superchargedcombustion engine 2. The combustion engine 2 may be a diesel engine. The vehicle lmay be a heavy vehicle. The vehicle l comprises an eXhaust line 3 receiving eXhaustgases from the combustion engine 2. The eXhaust line 3 comprises a turbine 4a of aturbo aggregate 4. The turbine 4a drives a compressor 4b of the turbo charger 4. Thecompressor 4b compresses air which is led, via a charged air line 5 to the combustionengine 2. The charged air line 5 comprises a charge air cooler 6 arranged at a front portion of the vehicle l.
    The vehicle l comprises a cooling system comprising an engine inlet line 7 directing coolant to the combustion engine 2. The engine inlet line 7 is provided with a pump 8 circulating a coolant in the Cooling system. The coolant leaving the combustion engine2 is received in an engine outlet line 9. A first valve member 10 in the form of a threeWay valve 10 is arranged at an end of the engine outlet line 9. The cooling systemcomprises a radiator bypass line 11 and a radiator 12. The first valve member 10 isable to receive coolant from the engine outlet line 9 and distribute a part of it to theradiator bypass line 11 and a remaining part of it to the radiator 12. The cooling systemcomprises a second valve member 14 in the form of a three Way valve. The secondvalve member 14 may receive coolant from the radiator bypass line lland direct it tothe engine inlet line 7 or to a condenser circuit 15 in Which the coolant cools a Workingmedium in a condenser 16 of a WHR system. ln the latter case, coolant from theradiator bypass line 11 and possible coolant from the radiator 12 are mixed anddirected to the condenser circuit 15. Altematively, the second valve member14receives coolant from the radiator 12 and directs it to the engine inlet line 7. Thecondenser circuit 15 comprises a condenser inlet line 15a directing coolant to thecondenser 16 and a condenser outlet line 15b directing coolant from the condenser 16 to the engine inlet line 7.
    Consequently, the vehicle is provided With a WHR- system (Waste Heat Recoverysystem). The WHR system comprises a pump 17 Which pressurizes and circulates aWorking medium in a WHR circuit 18. The Working medium may be ethanol, R245faor other kind of Working medium. The Working medium leaving the pump 17 enters athree Way valve 19. The three Way valve 19 can direct the Working medium to a firstheat exchanger 20 or a second heat exchanger 21. ln this case, the first heat exchanger20 and the second heat exchanger is arranged in parallel. The first heat exchanger 20 isconfigured to be used as evaporator and the second heat exchanger 21 is configured tobe used as a heat storage and evaporator. The second heat exchanger 21 has aconsiderably higher heat storage capacity than the first heat exchanger 20. The secondheat exchanger 21 may have a considerably higher mass than the first heat exchanger20. The second heat exchanger 21 may comprise a solid material heated by theexhaust gases, for example a ceran1ic material. Altematively or in combination, it cancomprise a phase changing material, for example tin Which melts at approximately230°C or zinc Which melts at approximately 430°C. A mix of two phase changing materials can also be used in the second heat exchanger 21.
    The Working medium is heated in at least one of the heat exchangers 20, 21 such that it is evaporated and superheated to a suitable temperature. The gaseous Working mediums leaving the heat eXchangers 20, 2l are received in a common line of theWHR circuit 18 directing the working medium to an eXpander 22. The workingmedium eXpands in the eXpander 22. The eXpander 22 generates a rotary motion whichmay be transmitted, via a suitable mechanical transmission, to a shaft of the drive trainof the vehicle l. After the working medium has passed through the eXpander 22, it isdirected to the condenser l6. The working medium is cooled in the condenser l6 bythe coolant in the condenser circuit l5 to a temperature at which it is condensed. Theliquid working medium is directed from the condenser l6, to a receiver 23. Workingmedium is sucked from the receiver 23 to the pump l7. The part of the WHR circuit 18located downstream of the pump l7 and upstream of the eXpander 22 comprises a highpressure side l8a of the WHR circuit 18. The part of the WHR circuit 18 locateddownstream of the eXpander 22 and upstream of the pump l7 comprises a low pressureside l8a of the WHR circuit l8.
    The eXhaust line 3 comprises a first heat eXchanger bypass line 3a and a second heateXchanger bypass line 3b. The exhaust line 3 comprises a first valve 24 controlling theeXhaust gas flow through the first heat eXchanger 20, a second valve 25 controlling theeXhaust gas flow through the first heat eXchanger bypass line 3a, a third valve 26controlling the eXhaust gas flow through the second heat eXchanger 2l and a fourthvalve 27 controlling the eXhaust gas flow through the second heat eXchanger bypassline 3b. The valves 24-27 are adjustable in a stepless manner. The valve 24-27 may bebutterfly valves. A control unit 28 controls the valves 24-27 and the three way valvel9. A first temperature sensor 29 sense the temperature of the eXhaust gases in aposition upstream of the second heat eXchanger 2l. A second temperature sensor 30senses the temperature of the second heat eXchanger 2l. The control unit 28 alsoreceives information about other operating parameters such as the load 3l of thecombustion engine 2 and the power demand 32 of the WHR system. The load 3l of thecombustion engine 2 is related to the amount of heat energy in the eXhaust gases. Inthis case, the WHR system is designed to have capacity to recover all heat energy in the eXhaust gases at a normal load of the combustion engine 2.
    When there is a normal load on the combustion engine 2 and a power demand of theWHR system, the control unit 28 controls the valve device l9 such that it directs theentire working medium flow to the first heat eXchanger 20. Furthermore, the controlunit 28 opens the first valve 24 and closes the second valve 25 such that the entire eXhaust gas flow is directed through the first heat eXchanger 20. ln this case, the Working medium is heated by the eXhaust gases in the first heat eXchanger 20 such it isevaporated and superheated to a suitable temperature before it is directed to theeXpander 22. In order to avoid unnecessary pressure drops in the eXhaust line 3, thecontrol unit 28 closes the third valve 26 and opens the fourth valve 27 such that the eXhaust gas floW is directed past the second heat eXchanger 2l.
    When there is a very high load on the combustion engine 2, the WHR system has notcapacity to utilize all heat energy in the eXhaust gases. ln this case, the control unit 28controls the valve device l9 such that it directs the Working medium floW to the firstheat eXchanger 20. The control unit 28 estimates the part of the eXhaust gases to bedirected to the first heat eXchanger 20 Without excessive superheating of the Workingmedium in the first heat eXchanger 20. The control unit 28 regulates the first valve 24and the second valve 25 such that the estimated eXhaust gas floW is directed throughthe first heat eXchanger 2l and the remaining part of the eXhaust gas floW is directedthrough the first valve bypass line 3a. The control unit 28 receives information aboutthe temperature of the eXhaust gases in a position upstream of the second heateXchanger 20 from the first temperature sensor 29 and about the temperature of thesecond heat eXchanger 2l from the second temperature sensor 30. ln view of thisinformation, the control unit 28 estimates if it is possible to heat the second heateXchanger 2l and if it results in a larger gain than the penalty caused by addedbackpressure in the eXhaust gas line 3. lf this is the case, the control unit 28 opens thethird valve 25 and closes the fourth valve 27 such that the eXhaust gases floW throughthe second heat eXchanger 2land heat it to a higher temperature. If it is not the case,the control unit 28 closes the third valve 25 and opens the fourth valve 27 such that theeXhaust gas floW is directed past the second heat eXchanger 2l. ln this case, the eWHR system recovers a part of the heat energy in the eXhaust gases and transform it tomechanical energy. An eXcess part of heat energy in the eXhaust gases is stored in the second heat eXchanger 2l.
    When there is no or a low load on the combustion engine 2 and a power demand of theWHR system, the control unit 28 determines if the temperature of the second heateXchanger 2l is necessary high to provide an efficient evaporation and superheating ofthe Working medium in the second heat eXchanger 2l. lf this is the case, the controlunit 28 controls the valve device l9 such that it directs the Working medium floW tothe second heat eXchanger 2l. In order to avoid unnecessary pressure drops in the eXhaust line 3, the control unit 28 closes the first valve 24 and opens the second valve 25 such that the entire eXhaust gas flow is directed past the first heat eXchanger 20. Thecontrol unit 28 opens the third valve 26 and closes the fourth valve 27 such that theentire eXhaust gas flow is directed through the second heat eXchanger 21. lf it is notpossible or suitable to heat the second heat eXchanger 2l, the control unit 28 shuts offthe WHR system.
    When there is a load on the combustion engine 2 and no power demand of the WHRsystem, the control unit 28 shuts off the pump l7 such that the circulation of theworking medium in the WHR circuit 18 is ceased. ln view of information about theload on the combustion engine 2, the temperature of the eXhaust gases and thetemperature of the second heat eXchanger 2l, the control unit 28 estimates if it ispossible to heat the second heat exchanger by the eXhaust gases and if it results in alarger gain than the penalty caused by added backpressure in the eXhaust gas line 3. lfthis is the case, the control unit 28 closes the first valve 24 and opens the second valve25 such that the entire eXhaust gas flow is directed past the first heat eXchanger 20.Furthermore, the control unit 28 opens the third valve 25 and closes the fourth valve 27such that the entire eXhaust gas flow is directed through the second heat eXchanger 2l.lf it is not possible or suitable to store heat energy in the second heat exchanger 2l, thecontrol unit 28 closes the third valve 26 and opens the fourth valve 27 such that the entire eXhaust gas flow is also directed past the second heat eXchanger 2l.
    Figs 2 shows an altemative embodiment of the WHR system. In this case, the first heateXchanger 20 and the second heat eXchanger 2l are arranged in series in the WHRcircuit l8. The first heat eXchanger 20 is arranged in a position upstream of the secondheat eXchanger 2l. A three way valve l9 is arranged in a position downstream of thefirst heat eXchanger 20 and upstream of the second heat eXchanger 2l. As aconsequence, the Working medium is always directed through the first heat eXchanger20. By means of the valve device l9, it is possible to direct the working mediumleaving the first heat eXchanger 20 to the second heat eXchanger 2lor past the second heat eXchanger 2l before it enters the eXpander 22.
    When there is a normal load on the combustion engine 2 and a power demand of theWHR system, the control unit 28 controls the valve device l9 such that the workingmedium flow from the first heat eXchanger 20 is directed past the second heateXchanger 2l and to the eXpander 22. Furthermore, the control unit 28 opens the first valve 24 and closes the second valve 25 such that the entire eXhaust gas flow is directed through the first heat eXchanger 20. The Working medium is heated by theeXhaust gases in the first heat eXchanger 20 such it is evaporated and superheated to asuitable temperature. ln order to avoid pressure drops in the eXhaust line 3, the controlunit 28 closes the third valve 26 and opens the fourth valve 27 such that the entire eXhaust gas floW is directed past the second heat eXchanger 21.
    When there is a very high load on the combustion engine, the WHR system has notcapacity to utilize all heat energy in the eXhaust gases. ln this case, the control unit 28controls the three Way valve l9 such that the Working medium floW from the first heateXchanger 20 is directed past the second heat eXchanger 2l and to the eXpander 22.The control unit 28 estimates the part of the eXhaust gas floW to be directed to the firstheat eXchanger 20 Without eXcessive superheating of the Working medium. The controlunit 28 regulates the first valve 24 and the second valve 25 such that such that theestimated eXhaust gases floW is directed to the first heat eXchanger 2l and a remainingpart of the eXhaust gas floW is directed to the first valve bypass line 3a. As aconsequence, the Working medium is evaporated and superheated to a suitabletemperature in the first heat eXchanger 20 before it is directed to the eXpander 22. Thecontrol unit 28 receives information about the temperature of the eXhaust gases in aposition upstream of the second heat eXchanger 20 from the first temperature sensor 29and about the temperature of the second heat eXchanger 2l from the secondtemperature sensor 30. ln vieW of this information, the control unit 28 estimates if it ispossible to heat the second heat exchanger 2l by the eXhaust gases and if it results in alarger gain than the penalty caused by added backpressure in the eXhaust gas line 3. lfthis is the case, the control unit 28 opens the third valve 25 and closes the fourth valve27 such that the eXhaust gas floW is directed through the second heat eXchanger 2l. lfit is not possible to heat the second heat eXchanger 2l, the control unit 28 closes thethird valve 25 and opens the fourth valve 27 such that the eXhaust gas floW is directedpast the second heat eXchanger 2l. ln this case, the WHR system recovers a maximumamount of heat energy in the eXhaust gases to mechanical energy. An eXcess part of the heat energy in the eXhaust gases is stored in the second heat eXchanger 2l.
    When there is no or a loW load on the combustion engine and a power demand of theWHR system, the control unit 28 determines if the temperature of the second heateXchanger 2l is necessary high enough to provide an efficient evaporation andsuperheating of the Working medium in the second heat exchanger 2l. lf this is the case, the control unit 28 controls the valve device l9 such that it directs the Working 11 medium flow from the first heat eXchanger 20 to the second heat eXchanger 2l. Inorder to avoid pressure drops in the eXhaust line 3, the control unit 28 closes the firstvalve 24 and opens the second valve 25 such that the entire eXhaust gas flow isdirected past the first heat eXchanger 20. The control unit 28 opens the third valve 26and closes the fourth valve 27 such that the entire eXhaust gas flow is directed throughthe second heat eXchanger 21. lf it is not possible or suitable to heat the second heateXchanger 2l, the WHR system is shut off.
    When there is a load on combustion engine and no power demand of the WHR system,the control unit 28 shuts off the pump l7 such that the circulation of the workingmedium in the WHR circuit 18 is ceased. In view of information about the load on thecombustion engine 2, the temperature of the eXhaust gases and the temperature of thesecond heat eXchanger 2l, the control unit 28 estimates if it is possible to heat thesecond heat eXchanger 2l by the eXhaust gases and if it results in a larger gain than thepenalty caused by added backpressure in the eXhaust gas line 3. If this is the case, thecontrol unit 28 closes the first valve 24 and opens the second valve 25 such that theentire eXhaust gas flow is directed past the first heat eXchanger 20. Furthermore, thecontrol unit 28 opens the third valve 25 and closes the fourth valve 27 such that theentire eXhaust gas flow is directed through the second heat eXchanger. If it is notpossible or suitable to store heat energy in the second heat eXchanger 2l, the controlunit 28 closes the third valve 26 and opens the fourth valve 27 such that the eXhaust gases flow also is directed past the second heat eXchanger 2l.
    Figs 3 shows a further alternative embodiment of the WHR system. ln this case, thefirst heat eXchanger 20 and the second heat eXchanger 2l is arranged in series in theWHR circuit l8 but the second heat eXchanger 2l is not arranged in the exhaust line 3.A three way valve l9 is arranged in a position downstream of the first heat eXchanger20 and upstream of the second heat eXchanger 2l. Also in this case, the Workingmedium is always directed through the first heat eXchanger 20. By means of the valvedevice l9, it is possible to direct the working medium flow leaving the first heateXchanger 20 to the second heat eXchanger 2l or past the second heat eXchanger 2l before it is directed to the eXpander 22.
    When there is a normal load on the combustion engine 2 and a power demand of theWHR system, the superheating of the working medium in the first heat eXchanger 20 is usually within a suitable temperature range. The control unit 28 controls the three way 12 Valve 19 such that the Working medium floW from the first heat eXchanger 20 isdirected past then second heat exchanger 2l and to the eXpander 22. Furthermore, thecontrol unit 28 opens the first valve 24 and closes the second valve 25 such that the entire eXhaust gas floW is directed through the first heat eXchanger 20.
    When there is a very high load on the combustion engine 2, the amount of heat energyin the eXhaust gases is high. As a consequence, the Working medium receives a toohigh superheating in the first heat eXchanger 20. The control unit 28 receivesinformation about the temperature of the second heat eXchanger 2l and determine if itis possible to de-superheat the Working medium in the second heat eXchanger 2l. Ifthis is the case, the control unit 28 controls the first valve 24 and the second valve 25such that the entire eXhaust gas floW is directed through the first heat eXchanger 20.Furthermore, the control unit 28 controls the three Way valve l9 such that it directs theWorking medium floW leaving the first heat eXchanger 20 to the second heat eXchanger2l. The Working medium is cooled in the second heat eXchanger 2l such that it has asuitable superheating When it leaves the second heat eXchanger 2l and enters theeXpander 22. At the same time the second heat eXchanger 2l is heated by thesuperheated Working medium. If it is not possible to de-superheat the Working mediumin the second heat eXchanger 2l, the control unit 28 controls the first valve 24 and thesecond valve 25 such that a part of the eXhaust gas floW is directed through the firstheat eXchanger 2l such that the Working medium receives a suitable superheating inthe first heat eXchanger 20.
    When there is no or a loW load on the combustion engine and a poWer demand of theWHR system, the control unit 28 determines if the temperature of the second heateXchanger 2l is necessary high to provide an efficient evaporation and superheating ofthe Working medium. If this is the case, the control unit 28 controls the valve device 19such that it directs the Working medium from the first heat eXchanger 20 to the secondheat eXchanger 2l. In order to avoid pressure drops in the eXhaust line 3, the controlunit 28 closes the first valve 24 and opens the second valve 25 such that the entireeXhaust gas floW is directed past the first heat eXchanger 20. If it is not possible orsuitable to heat the second heat eXchanger 2l, the WHR system is shut off.
    When there is a load on combustion engine and no poWer demand of the WHR system,the circulation of the Working medium in the WHR circuit l8 is to continue. In vieW of information about the load on the combustion engine 2, the temperature of the eXhaust 13 gases and the temperature of the second heat exchanger 2l, the control unit 28estimates if it is possible to evaporate and superheat the Working medium in the secondheat exchanger 2l lf this is the case, the control unit 28 opens the first Valve 24 andcloses the second Valve 25 such that the entire eXhaust gas floW is directed through thefirst heat exchanger 20. Furthermore, the control unit 28 controls the Valve device l9such that it directs the Working medium floW from the first heat exchanger 20 to thesecond heat exchanger 2l. lf it is not possible or suitable to heat the second heatexchanger 2l, the WHR system is shut off.
    The invention is not restricted to the described embodiment but may be Varied freely Within the scope of the claims.
    权利要求:
    Claims (13)
    [1] 1. An arrangement for recovering heat energy in eXhaust gases from a combustionengine (2), Wherein the arrangement comprises a WHR system comprising a WHRcircuit (18) With a circulating Working medium, a first heat eXchanger (20) in the formof an evaporator arranged at a high pressure side (l8a) of the WHR circuit (18) inWhich the Working medium is heated by eXhaust gases from the combustion engine (2),and an eXpander (22) generating mechanical energy from the Working medium,characterized in that the WHR system comprises a second heat eXchanger (21)arranged on the high pressure side (l8a) of the WHR circuit (18) having at least twicethe heat storage capacity as the first heat eXchanger (20) and a valve device (24-27, 19)configured to direct eXhaust gases and Working medium to the heat eXchangers (20,21) in a manner such that the Working medium is evaporated and superheated in at least one of said heat eXchanger (20, 21) before it is directed to the eXpander (2).
    [2] 2. An arrangement according to claim 1, characterized in that the second heat eXchanger (21) has a larger mass than the first heat eXchanger (20).
    [3] 3. An arrangement according to claim 1 or 2, characterized in that the second heat eXchanger (21) comprises a solid material to be heated by the eXhaust gases.
    [4] 4. An arrangement according to any one of the preceding claims, characterized in thatthe second heat eXchanger (21) comprises a phase changing material to be heated by the eXhaust gases.
    [5] 5. An arrangement according to any one of the preceding claims, characterized in thatthe second heat eXchanger (21) comprises a mix of tWo phase changing materials to be heated by the eXhaust gases.
    [6] 6. An arrangement according to any one of the preceding claims, characterized in thatthe first heat eXchanger (20) and the second heat eXchanger (21) are arranged inparallel in the WHR circuit (18) and that the valve device comprises a valve (19)directing the Working medium to the first heat eXchanger (29) or the second heat eXchanger (21).
    [7] 7. An arrangement according to any one of the preceding c1aims 1 to 5, characterizedi_n that the first heat eXchanger (20) and the second heat eXchanger (21) are arranged inseries in the WHR circuit (18), and that the va1ve device comprises a va1ve (19)arranged in a position doWnstream of the first heat eXchanger and upstream of thesecond heat eXchanger between said heat eXchangers (20, 21) directing the Workingmedium 1eaving the first heat eXchanger (20) to the second heat eXchanger (21) or past the second heat eXchanger (21).
    [8] 8. An arrangement according to any one of the preceding c1aims, characterized in thatthe first heat eXchanger (20) and the second heat eXchanger (21) are arranged in an eXhaust1ine (3) of the combustion engine (2).
    [9] 9. An arrangement according to any one of the preceding c1aims 1 to 5 and 7,characterized in that the first heat eXchanger (20) is arranged in an eXhaust 1ine (3) ofthe combustion engine (2) and the second heat exchanger (21) is arranged outside the eXhaust1ine (3) of the combustion engine (2).
    [10] 10. An arrangement according to any one of the preceding c1aims, characterized in thatthe it comprises a first heat eXchanger bypass 1ine (3a) and that the va1ve devicecomprises at 1east one va1ve (24, 25) contro11ing the eXhaust gas floW through the firstheat eXchanger (20) and the first heat eXchanger bypass 1ine (3a).
    [11] 11. An arrangement according to any one of the preceding c1aims 1-8 and 10,characterized in that it comprises second heat eXchanger bypass 1ine (3b) and that theva1ve device comprises at 1east one va1ve (26, 27) contro11ing the eXhaust gas floWthrough the second heat eXchanger (21) and the second heat eXchanger bypass 1ine(3b).
    [12] 12. An arrangement according to any one of the preceding c1aims, characterized in thatit comprises a contro1 unit (28) configured to contro1 the va1ve device (19) by means of information from at 1east one operating parameter.
    [13] 13. An arrangement according to c1aim 12, characterized in that said operatingparameter is re1ated to at 1east one of the fo11oWing parameters the temperature of theeXhaust gases, the temperature of the second heat eXchanger, the 1oad (31) of thecombustion engine (2) and the power demand (32) of the WHR system.
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    同族专利:
    公开号 | 公开日
    SE540362C2|2018-08-07|
    DE102017006171A1|2018-01-11|
    DE102017006171B4|2021-10-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE102010042401A1|2010-10-13|2012-04-19|Robert Bosch Gmbh|Device and method for waste heat utilization of an internal combustion engine|
    AT512921B1|2012-07-31|2013-12-15|Man Truck & Bus Oesterreich Ag|Method for controlling a heat recovery system in a motor vehicle|
    WO2014096892A1|2012-12-19|2014-06-26|Renault Trucks|Engine arrangement comprising a separate heat storage device|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1651010A|SE540362C2|2016-07-07|2016-07-07|An arrangement for recovering heat energy in exhaust gases from a combustion engine|SE1651010A| SE540362C2|2016-07-07|2016-07-07|An arrangement for recovering heat energy in exhaust gases from a combustion engine|
    DE102017006171.8A| DE102017006171B4|2016-07-07|2017-06-29|Arrangement for the recovery of thermal energy in exhaust gases from an internal combustion engine|
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