SE542594C2 - Waste heat recovery system comprising receiver tank heatable by coolant fluid - Google Patents

Waste heat recovery system comprising receiver tank heatable by coolant fluid

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Publication number
SE542594C2
SE542594C2 SE1851320A SE1851320A SE542594C2 SE 542594 C2 SE542594 C2 SE 542594C2 SE 1851320 A SE1851320 A SE 1851320A SE 1851320 A SE1851320 A SE 1851320A SE 542594 C2 SE542594 C2 SE 542594C2
Authority
SE
Sweden
Prior art keywords
heater
line
working fluid
channel
outlet
Prior art date
Application number
SE1851320A
Other languages
Swedish (sv)
Other versions
SE1851320A1 (en
Inventor
Ola Hall
Thomas Sederholm
Zoltan Kardos
Original Assignee
Scania Cv Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to SE1851320A priority Critical patent/SE542594C2/en
Priority to DE112019004542.3T priority patent/DE112019004542T5/en
Priority to PCT/SE2019/050931 priority patent/WO2020085968A1/en
Publication of SE1851320A1 publication Critical patent/SE1851320A1/en
Publication of SE542594C2 publication Critical patent/SE542594C2/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting from exhaust energy
    • F01N5/02—Exhaust or silencing apparatus combined or associated with devices profiting from exhaust energy the devices using heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
    • F02G5/02—Profiting from waste heat of exhaust gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K15/00—Adaptations of plants for special use
    • F01K15/02—Adaptations of plants for special use for driving vehicles, e.g. locomotives
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/065—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/12—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engines being mechanically coupled
    • F01K23/14—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engines being mechanically coupled including at least one combustion engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K9/00—Plants characterised by condensers arranged or modified to co-operate with the engines
    • F01K9/003—Plants characterised by condensers arranged or modified to co-operate with the engines condenser cooling circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D3/00—Accumulators for preheated water
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D5/00—Controlling water feed or water level; Automatic water feeding or water-level regulators
    • F22D5/26—Automatic feed-control systems
    • F22D5/36—Automatic feed-control systems for feeding a number of steam boilers designed for different ranges of temperature and pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K13/00—General layout or general methods of operation of complete plants
    • F01K13/02—Controlling, e.g. stopping or starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/22—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a condensation chamber
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Abstract

The present disclosure relates to a waste heat recovery (WHR) system (9) for a vehicle (1). The WHR system comprises a receiver tank (27) having a substantially constant inner volume and being equipped with a heater (41) having a heater inlet (43) adapted to be fluidly connectable with an engine cooling system (71), and wherein the heater is arranged to facilitate heat transfer from coolant fluid in the heater to working fluid in the receiver tank.The present disclosure also relates to an integrated system comprising a WHR system and an engine cooling system. The disclosure further relates to methods for controlling and shutting down such a WHR system, as well as a vehicle comprising such a WHR system.

Description

1 Waste heat recovery system comprising receiver tank heatable by coolant fluid TECHNICAL FIELD The present invention relates to a waste heat recovery system, methods for controlling such a system, and a vehicle comprising such a waste heat recovery system.
BACKGROUND ART Vehicle manufacturers are today striving to increase engine efficiency and reduce fuelconsumption. This is especially an issue for manufacturers of heavy vehicles, such as trucksand buses. One way of improving engine efficiency and fuel consumption is waste heatrecovery. ln vehicles with combustion engines most ofthe energy from the fuel does notproduce useful work, but instead is dissipated as heat through the exhaust pipes and theengine cooling system. By the use of a waste heat recovery system the waste heat may insteadbe used to heat various vehicle components or to produce electricity or mechanical work.Such mechanical work may for example be transferred to the driveline and thus be used to propel the vehicle.
A waste heat recovery (WHR) system typically comprises at least one heat exchangertransferring heat between a heat source, such as exhaust gases, and a working fluid. The heattransfer between the working fluid and the heat source is an exchange of energy resulting in achange in temperature of both the working fluid and heat source. A waste heat recoverysystem may for example be based on a Rankine cycle, or an organic Rankine cycle for lowtemperature heat recovery. Such systems typically comprise a working fluid, a pump forcirculating the working fluid in a circuit, at least one evaporator (heat exchanger), anexpansion device (expander), a condenser and an expansion tank for receiving excess workingliquid. The working fluid in such waste heat recovery system is suitably in a liquid state to startwith. The pump pressurizes the working fluid which is pumped through the evaporator. ln theevaporator, the working fluid is heated by heat exchange with a heat source, for example exhaust gases, led through the evaporator. This causes the working fluid to evaporate. The 2 resulting vapour is subsequently expanded in the expansion device, e.g. a turbine. By means ofthe expansion device the recovered heat may thereby be converted into mechanical work orelectrical energy. The vapour is thereafter coo|ed in the condenser, such that the working fluidis brought back to its initial liquid state. The condenser is thus typically connected to a coolingsystem, which may be part ofthe engine cooling system or a separate cooling system. Aftercondensing back to the liquid state, the working fluid may be received in the expansion tank.The working fluid received in the expansion tank is thus ready for further pumping around the WHR circuit. lt is essential that the working fluid after the on the low-pressure side ofthe WHR circuit, i.e.between the condenser and the pump inlet, is sub-coo|ed, i.e. coo|ed to a temperature belowthe boiling point at the pressure prevailing in the low-pressure side ofthe WHR circuit. Theboiling point may also be referred to as the saturation temperature or condensationtemperature of the working fluid. lf the working fluid is not sufficiently sub-coo|ed, transientincreases in temperature or decreases in pressure may cause undesired boiling or flashing ofthe liquid. This may for example result in cavitation in the working fluid pump, potentiallyleading to damage of pump components. ln order to avoid such problems, the working fluidentering the pump must be sufficiently subcooled, i.e. held under conditions sufficiently removed from saturation.
DE 102009050068 A1 describes an internal combustion engine with a cooling circuit and aClausius-Rankine cycle for waste heat recovery. ln the Clausius-Rankine cycle a surge tank isprovided to compensate for volume and/or pressure fluctuations. ln an embodiment, thesurge tank comprises a primary chamber and a secondary chamber, which are divided by amembrane. The primary chamber is in communication with the Clausius-Rankine cycle and thesecondary chamber is in communication with a pressure regulator. This makes it possible tocontrol or regulate a condensing pressure and thus a condensation temperature ofthe Clausius-Rankine cycle working fluid.
There remains a need for improved means for controlling a waste heat recovery system.
SUMMARY OF THE INVENTION The inventors of the present invention have identified a number of shortcomings in prior artwaste heat recovery systems. Expansion tanks comprising a membrane or bladder capable ofbeing actively pressure regulated are complex in design, require a source of pressurizing f|uidsuch as compressed air (which is not readily available in all vehicles), and, most importantly,are prone to premature failure. A potential factor in the premature failure of the expansiontank is the constant mechanical stress the membrane or bladder material undergoes due toexpansion and contraction of the expansion tank volume. Another potential factor is the oftenpoor compatibility between the material ofthe membrane/bladder, which is often rubber or a synthetic elastomer, and the working f|uid, which is often an organic solvent. lt would be advantageous to achieve a waste heat recovery system overcoming, or at leastalleviating, at least some of the above mentioned shortcomings. ln particular, it would bedesirable to provide a waste heat recovery system that has an improved longevity, especially with regard to the tank for storing working f|uid. ln order to better address one or more of these concerns, a waste heat recovery system for avehicle is provided, the waste heat recovery system having the features defined in the independent claims.The waste heat recovery system comprises: - a working f|uid pump; - an evaporator; - an expander; - a condenser; - a pump outlet line arranged to channel working f|uid from the working f|uid pump to theevaporator; - an evaporator outlet line arranged to channel working f|uid from the evaporator to theexpander; - an expander outlet line arranged to channel working f|uid from the expander to the condenser; 4 - a condenser outlet line arranged to channel working fluid from the condenser to the workingfluid pump; - a receiver tank comprising a tank inlet and a tank outlet; - a tank inlet line arranged to channel working fluid from a first junction in the condenseroutlet line to the tank inlet; and - a tank outlet line arranged to channel working fluid from the tank outlet to a second junctionin the condenser outlet line, wherein the second junction is arranged between the first junction and the working fluid pump.
The receiver tank has substantially constant inner volume or a constant inner volume and isequipped with a heater having a heater inlet adapted to be fluidly connectable with an enginecooling system, and wherein the heater is arranged to facilitate heat transfer from a coolant fluid in the heater to a working fluid in the receiver tank.
By utilizing a receiver tank having a constant or during operation substantially constant innervolume, the receiver tank volume is no longer required to contract and expand in order toregulate the WHR system, and the receiver tank may therefore be constructed of robust,relatively inelastic materials that tolerate prolonged contact with working fluid. The receivertank may for example be constructed from metal, such as stainless steel. Due to the receivertank being equipped with a heater utilizing coolant fluid from the cooling system as heatingmedium, working fluid contained in the receiver tank may be vaporized using the heater.Vaporizing working fluid in this manner leads to an increase in pressure in the receiver tankand its environs, including within the condenser. This increase in condensation pressure leadsto a corresponding increase in condensation temperature, and means that the degree of sub-cooling achieved by the condenser may be controlled by the heater. Note that the heatcontained in the coolant fluid would otherwise be lost in the radiator, so the present inventioneffectively utilizes heat that otherwise would be discarded in order to control the WHR system.
According to another aspect of the present invention, an integrated system for a vehicle isprovided, in accordance with the appended claims. The integrated system comprises a waste heat recovery system and an engine cooling system. the waste heat recovery system for the integrated system comprises: - a working fluid pump; - an evaporator; - an expander; - a condenser; - a pump outlet line arranged to channel working fluid from the working fluid pump to theevaporator; - an evaporator outlet line arranged to channel working fluid from the evaporator to theexpander; - an expander outlet line arranged to channel working fluid from the expander to thecondenser; - a condenser outlet line arranged to channel working fluid from the condenser to the workingfluid pump; - a receiver tank comprising a tank inlet and a tank outlet; - a tank inlet line arranged to channel working fluid from a first junction in the condenseroutlet line to the tank inlet; and - a tank outlet line arranged to channel working fluid from the tank outlet to a second junctionin the condenser outlet line, wherein the second junction is arranged between the first junction and the working fluid pump.
The engine cooling system for the integrated system comprises: - a radiator; - an engine outlet channel arranged to collect coolant fluid exiting an engine; and - a radiator return line arranged to channel coolant fluid from the engine outlet channel to the radiator. ln the integrated system the receiver tank is equipped with a heater having a heater inletarranged in fluid connection with the engine outlet channel via a heater feed line. The heaterfeed line is arranged to channel coolant fluid from the engine outlet channel to the heaterinlet. The heater is arranged to facilitate heat transfer from coolant fluid in the heater to working fluid in the receiver tank. 6The temperature of the coolant fluid in the engine outlet channel is relatively consistent and ishot enough to provide for vaporization of the working fluid in the receiver tank when fedthrough the heater. Such an integrated system therefore readily permits control ofthe condensation temperature of the working fluid in the condenser.
A heater return line may be arranged to channel coolant fluid from an outlet ofthe heater tothe engine outlet channel or radiator return line. The heater return line may form a junctionwith the engine outlet channel at a point in closerflow proximity to the radiator return line than a junction of the heater feed line with the engine outlet channel.
A recuperator may be arranged to facilitate heat transfer from coolant fluid in the heaterreturn line to working fluid in the pump outlet line. This allows recovery of heat that otherwise would be lost in the radiator, and thus increases the overall efficiency ofthe WHR system.
A heater by-pass line may be arranged to channel coolant fluid from the heater feed line tothe heater return line, wherein the heater by-pass line forms a junction with the heater returnline at a point between the heater and the recuperator. ln such a case, a heater by-pass valvemay be arranged at a junction ofthe heater by-pass line and the heater feed line, wherein theheater by-pass valve is arranged to controllably redirect a flow of coolant fluid from the heaterfeed line to the heater by-pass line. Such an arrangement allows coolant fluid to be directedthrough the recuperator even when coolant fluid flow though the heater is not desired. Thisfurther increase the proportion of waste heat from the engine that may be converted to useful work in the WHR system.
A heater feed valve may be arranged at a junction of the heater feed line and the engineoutlet channel, wherein the heater feed valve is arranged to controllably redirect a flow ofcoolant fluid from the engine outlet channel to the heater feed line. This allows the flow ofcoolant fluid passing through the heater to be readily controlled without altering the coolantfluid flow to other components in the cooling circuit, such as the engine and/or condenser.
Thus, overall control of the WHR is facilitated.
A heater feed pump may be arranged in the heater feed line or the heater return line, whereinthe heater feed pump is arranged to controllably direct a flow of coolant fluid from the engine outlet channel to the heater feed line. This allows the flow of coolant fluid through the heater 7to be controlled independently of the coolant pump and permits a flow of coolant fluid in the heater even when the coolant pump is not circulating coolant fluid in the main cooling circuit.
A recuperator may be arranged to facilitate heat transfer from coolant fluid in the engineoutlet channel to working fluid in the pump outlet line. This allows a flow of coolant fluid tobe directed through the recuperator independently of any coolant fluid flow though theheater. This further increase the proportion of waste heat from the engine that may be converted to useful work in the WHR system.
A recuperator feed line may be arranged to channel coolant fluid from the engine outletchannel to the recuperator. ln such a case, a recuperator return line may be arranged tochannel coolant fluid from the recuperator to the engine outlet channel or radiator returnline. The recuperator feed line may be arranged to junction with the engine outlet channel ata point downstream ofthe junction with the heater return line, i.e. in closer flow proximity tothe radiator return line than the heater return line. The recuperator return line may bearranged to junction with the engine outlet channel at a point downstream ofthe junctionwith the recuperator feed line return line. A recuperator feed pump may be arranged in therecuperator feed line or recuperator return line, wherein the recuperator feed pump isarranged to controllably direct a flow of coolant fluid from the engine outlet channel to therecuperator feed line. Such an arrangement allows a flow of coolant fluid to be directedthrough the recuperator independently of any coolant fluid flow through the heater or in themain cooling circuit. For example, this permits a flow of coolant fluid through the recuperator even when the coolant pump is not circulating coolant fluid in the main cooling circuit.
A first controllable flow regulating means may be arranged in the tank inlet line, and a secondcontrollable flow regulating means may be arranged in the tank outlet line. Such flowregulating means allow the receiver tank to be isolated. For example, during shutdown oftheWHR system, the WHR system may be controlled to ensure that vaporized working fluid ispresent only in the receiver tank and the rest of the system is filled with liquid working fluid.Once such a state is achieved, the receiver tank may be isolated by closure of the first andsecond flow regulating means, and the working fluid pump may then be switched off to stopworking fluid circulating in the WHR system. Upon further cooling ofthe working fluid, the vaporized working fluid condenses and sub-atmospheric pressures are generated in the 8receiver tank. However, the receiver tank is easily designed to withstand such low pressures.Other WHR system components which are more difficult to seal against sub-atmospheric pressures, such as the expander, are therefore protected from exposure to such conditions.
A third controllable flow regulating means may be arranged in the condenser outlet linebetween the first junction and the second junction. This allows the flow of working fluid to be directed via the receiver tank or directly through the condenser outlet line as desired.
The receiver tank may be arranged to separate gaseous working fluid from liquid workingfluid. The receiver tank may be arranged to channel liquid working fluid to the tank outlet.Such an arrangement ensures that the working fluid channelled to the working fluid pump is always in liquid form and prevents damage to the pump by, for example, cavitation.
A desiccator medium may be contained in the receiver tank. This allows the removal ofmoisture from the working fluid and ensures predictable and reliable behaviour ofthe working fluid.
The waste heat recovery system of the integrated system may be a subcooler free system. The ability to regulate condensation pressure using the heater renders a sub-cooler unnecessary.
According to another aspect of the invention, a method for controlling an integrated system asdescribed herein is provided, the method being in accordance with the appended claims. Themethod comprises a step of increasing condensation pressure in the condenser by controllablydirecting a flow of coolant fluid from the engine outlet channel through the heater. Bydirecting a flow of coolant fluid from the engine outlet channel through the heater, workingfluid contained in the receiver tank is vaporized and the condensation pressure is increased.This provides a corresponding increase in the condensation temperature and allows thecondensation temperature of the working fluid to be controlled without resorting to the useof working fluid tanks having a variable volume that can be regulated, as known in the prior art.
According to a further aspect of the invention, a method for shutting down an integratedsystem as described herein is provided, the method being in accordance with the appendedclaims. The method comprises a step of, during a shutdown phase of the waste heat recovery system, isolating the receiver tank by closing the first controllable flow regulating means and 9second controllable flow regulating means, such that working fluid contained in a remainderof the waste heat recovery system has a temperature below a condensation temperature ofthe working fluid at ambient pressure. This allows the sub-atmospheric pressures generatedupon shutdown ofthe WHR system to be localised to the receiver tank, where such pressurescan be easily accommodated. Thus, WHR system components which are much more difficultto engineer to withstand negative pressures, such as the expander, are therefore not required to withstand such pressures.
According to yet another aspect of the invention, a vehicle comprising a waste heat recovery system or integrated system as described herein is provided.
Further objects, advantages and novel features of the present invention will become apparent to one skilled in the art from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the present invention and further objects and advantages of it,the detailed description set out below should be read together with the accompanyingdrawings, in which the same reference notations denote similar items in the various diagrams, and in which: Fig. 1 schematically illustrates a vehicle according to the invention; Fig. 2 schematically illustrates a WHR system and integrated system according to anembodiment ofthe invention; Fig. 3 schematically illustrates a WHR system and integrated system according toanother embodiment of the invention; Fig. 4 schematically illustrates a WHR system and integrated system according to afurther embodiment of the invention; Fig. 5 is a flowchart schematically illustrating a method for controlling the WHR system according to the invention; and Fig. 6 is a flowchart schematically illustrating a method for shutting down the WHR system according to the invention.
DETAILED DESCRIPTION The present invention is based upon the insight that a waste heat recovery system comprisinga receiver tank may be controlled to obtain appropriate subcooling in the condenser byequipping the receiver tank with a heater and using the heater to vaporize working fluid in thereceiver tank, thus controlling the condensation pressure at the condenser. The heater operates using hot coo|ant fluid from the engine coo|ing system as the heating medium.
The waste heat recovery system may be based on a Rankine cycle or organic Rankine cycle. Thewaste heat recovery system comprises a working fluid pump; an evaporator; an expander; acondenser; and a receiver tank equipped with a heater. The working fluid is compressed andpumped as a liquid by the pump to the evaporator. ln the evaporator, the working liquid isheated and vaporised by heat exchange from a heat source passing through the evaporator. Theworking fluid, now in the gaseous phase, flows to the expander where it is allowed to expand,doing mechanical work. The expanded vapour is then cooled back to liquid again by thecondenser. ln this application, the term ”downstream” as applied to the WHR system is definedas the typical direction of flow of the working fluid in the WHR circuit from the working fluid pump via the evaporator, expander and condenser to the receiver tank.
A variety of working fluids may be chosen for use in the waste heat recovery system, dependingon the quality of the heat source(s) to be utilised. The working fluid may be water, or may be an organic liquid such as for example ethanol or R-245fa.
The working fluid pump ofthe waste heat recovery system may be of any type known in the art, and may, for example, suitably be electrically driven or mechanically driven. ln the evaporator, the working liquid is heated and vaporised by heat exchange from a heatsource. The evaporator may be ofany type known in the art, for example a plate heat exchanger.The heat source may be any available source of waste heat in a vehicle, such as the vehicle exhaust gases, hot oil from a retarder or hot liquids from the vehicle coo|ing system. The waste 11heat recovery system may have a number of evaporators, each for a separate source of waste heat.
The working fluid is vaporised in the evaporator, and therefore the working fluid arriving at theexpander should be in gaseous form. A channel bypassing the expander, equipped with a valve,may be provided in the working fluid circuit in order to direct non-evaporated fluid past theexpander without passing through the expander. This may for example be useful during start up and initial operation ofthe vehicle, or if no mechanical work is needed from the WHR system.
The expander can be of any type known in the art, including but not limited to turbine, screw,scroll, or piston expanders. The mechanical work produced in the expander may be provided toa generator for electricity production, or may be transferred to the vehicle powertrain, e.g. the crankshaft, using for example a clutch or freewheel.
The condenser may be of any type known in the art. The condenser condenses the working fluidback to the liquid phase. lt may be connected to a cooling circuit, which may for example be thestandard engine cooling system, or may be provided with a dedicated cooling system. Thecooling power of the condenser may be regulated in order to ensure that an appropriate degreeof subcooling at an advantageous temperature is obtained. This may be performed by regulatingthe temperature of a coolant fluid passing through the condenser, or by regulating the flow ofcoolant fluid through the condenser. However, the condenser may not be able to providesufficient cooling in all circumstances, such as for example during full load conditions. Thepresent invention provides a further means of regulating subcooling by regulating pressure inthe low-pressure side of the waste heat recovery system by heating working fluid contained in the receiver tank.
The condensed working fluid is collected in a receiver tank. The receiver tank has a fixed innervolume, i.e. it does not possess a membrane capable of varying the inner volume ofthe tank asknown in prior art solutions. Since the receiver tank is not required to vary in volume, it may bemanufactured from strong and stable materials, for example from metals such as stainless steel.This considerably increases the service life of the tank as compared to tanks having for example rubber bladders or membranes. 12The receiver tank may be configured as commonly known in the art in order to facilitategravitational phase separation of working fluid into a vapour phase and a liquid phase. This maybe achieved by having the receiver tank outlet located at the bottom ofthe tank (as orientatedwhen mounted on the vehicle). This ensures that working fluid in the vapour phase is trappedin the receiver tank and is not conveyed through the WHR system towards e.g. the pump. Thereceiver tank inlets may be located high up in the receiver tank (as orientated when mountedon the vehicle). Liquid working fluid entering the tank thus falls to the bottom of the tank andvaporized working fluid forms a vapour column above the pooled liquid working fluid. Thereceiver tank may contain a desiccant material in order to remove any water entering the wasteheat recovery system. The receiver tank may further comprise a filter arranged to prevent circulation of solids or particulates in the WHR system.
The receiver tank inlet and outlet are connected to the condenser outlet line, i.e. the conduitchannelling working fluid between the condenser and the working fluid pump. The tank inlet isconnected by a receiver inlet line and the tank outlet is connected by a receiver outlet linearranged downstream ofthe receiver inlet line. Flow regulating means, such as controllable stopvalves, may be arranged in the receiver inlet line and receiver outlet line. This allows the receivertank to be isolated when required. For example, during shutdown of the WHR system, thesystem may be controlled to ensure that only the receiver tank is subjected to sub-atmosphericpressures and that the rest of the system is filled with liquid working fluid and thus not subjectto sub-atmospheric pressures. This facilitates design and construction of the WHR system sinceit means that only the seals of the receiver must be designed to withstand sub-atmosphericpressure, and that other seals in the system must only protect against leakage outwards from the system due to elevated pressures.
A flow regulating means, such as a controllable stop valve, may be arranged in the section ofthe condenser outlet line between the junction with the receiver inlet line and the junction withthe receiver outlet line. This allow flow of working fluid to be directed to the receiver tank or to bypass the receiver tank as desired.
During normal operation of the waste heat recovery system the receiver tank typically containsa volume of liquid working fluid, and may for example normally be approximately half-full with liquid working fluid. This is because the volume of working fluid required to fill the circuit is 13greater at lower temperatures than at higher temperatures, and the volume of working fluidshould be dimensioned to be capable of always filling the circuit. However, the receiver tank harbours the excess working fluid, thus preventing overfilling of the system.
The present invention utilizes vaporization ofthe working fluid contained in the receiver tank inorder to control subcooling ofthe working fluid from the condenser. By vaporizing working fluidin the receiver tank, the pressure and/or volume occupied in the receiver tank by vaporizedworking fluid is increased. Assuming that the receiver tank has a constant volume, this increasein volume of the vapour phase is compensated by lowering the liquid level in the receiver tank,thus forcing working fluid into the condenser and resulting in a greater degree of subcooling ofworking fluid in the condenser. This effect may be utlilized for example in situations where thecondenser is incapable of providing sufficient cooling power to subcool the working fluid. Onthe contrary, if the condenser is providing excessive subcooling, the pressure prevailing in thereceiver tank should be decreased. This may for example be achieved by directing a flow ofcooled working fluid from the condenser through the receiver tank in order to lower the temperature in the receiver tank. ln order to provide for vaporization of the working fluid contained in the receiver tank, thereceiver tank is equipped with a heater. Heating medium passing through the heater providesheat transfer to the working fluid contained in the receiver, thus acting to vaporize the workingfluid in the receiver and increase the condensation pressure. Thus, the receiver tank mayresemble a shell and tube heat exchanger with the receiver tank corresponding to the shell and the heater corresponding to the tube. ln the present invention the heating medium passing through the heater is coolant fluidredirected from the engine outlet channel in the engine cooling system. Coolant fluid redirectedfrom this line typically has a relatively consistent temperature and is usually sufficiently hot inorder to provide vaporization of the working fluid in the receiver tank. For example, the coolantfluid exiting the engine is typically approximately 95 °C, and the boiling point of ethanol, whichis a commonly utilized working fluid in organic Rankine systems, is approximately 78 °C atatmospheric pressure. The engine outlet channel may have a relatively large volume and thusact as a reservoir for hot coolant fluid, from which flows of coolant may be drawn off and returned without adversely impacting upon the fluid dynamics of the cooling system. 14The engine cooling system may suitably comprise a coolant pump arranged to circulate acoolant fluid, an engine outlet channel arranged to collect hot coolant fluid exiting the engine,a radiator arranged for cooling the coolant fluid, and one or more valve units for controlling theflow of the coolant fluid through the cooling system. The term ”downstream” as applied to theengine coolant system is defined as the typical direction of flow of the coolant fluid in the enginecooling circuit from the coolant pump via the engine, engine outlet channel and radiator returnline to the radiator. A heater feed line and return line channels coolant fluid to and from theheater. lf the condenser is also cooled from the engine cooling system, it may for example becooled using a dedicated condenser feed loop branching off from the main cooling circuit andcontrolled by one or more valves or pumps. This condenser fed loop may preferably be suppliedwith cold coolant fluid, for example coolant fluid having exited the radiator and not having yet passed through the engine.
The WHR system may comprise a recuperator that utilises the heat of the coolant fluid leavingthe heater in order to preheat the working liquid prior to entering the evaporator. This reducesheat loss in the radiator and improves the overall conversion of waste engine heat into usefulmechanical work. The recuperator may be any type of recuperator known in the art, such as acounter-current heat exchanger utilizing tuber or plates. The recuperator may be arranged inseries with the heater such that coolant fluid flowing through the recuperator has necessarilypreviously passed through the heater. However, the recuperator and heater may be arrangedsuch that hot coolant fluid may always flow through the recuperator, regardless of whether ithas previously passed through the heater or not. This may be achieved by providing the enginecooling system with a heater by-pass arrangement (line and valve) allowing the heater to be by-passed. This may alternatively be achieved by having separate heater and recuperator feedloops (feed line and return line) running from the engine outlet channel to the heater andrecuperator respectively. These feed loops may be equipped with dedicated pumps (heater feedpump and/or recuperator feed pump), thus allowing a flow of coolant fluid through the feed loop even when the coolant pump is not pumping.
The waste heat recovery system and/or engine cooling system may be configured in analternative manner or may comprise further components as known in the art. For example, theWHR and/or engine cooling systems may comprise sensors, such as temperature and pressure sensors. The WHR and/or engine cooling systems may comprise further valves. The WHR system may comprise further condensers in order to cool the working fluid in several stages, or furtherexpanders in order to expand the working fluid in several stages. However, the presentinvention results in a lesser need for a dedicated subcooler in the waste heat recovery system and therefore such a component may not be required.
The waste heat recovery system and/or engine cooling system may suitably be controlled usinga control unit. The control unit may suitably be connected to the waste heat recovery systemand/or the cooling system. The control unit may suitably be connected to the evaporator, theexpander and the pump of the waste heat recovery system. The control unit may suitably beconnected to the coolant pump and any further means of regulating the cooling system, suchas further pumps or control valves. The control unit may suitably be connected to any valvescontrolling the flow of heat source through the evaporator. The control unit may be the enginecontrol unit or may comprise a plurality ofdifferent control units. A computer may be connected to the control unit.
The temperature of the working liquid leaving the condenser may be measured directly or itmay be determined virtually. For example, if the temperature and flow of vapour entering thecondenser is known, and the cooling characteristics of the condenser are known, the temperature of the working fluid leaving the condenser may be readily determined.
The invention will now be described in more detail with reference to certain exemplifyingembodiments and the drawings. However, the invention is not limited to the exemplifyingembodiments discussed herein and/or shown in the drawings, but may be varied within thescope of the appended claims. Furthermore, the drawings shall not be considered drawn to scale as some features may be exaggerated in order to more clearly illustrate certain features.
Figure 1 schematically illustrates a side view of a vehicle 1 comprising an internal combustionengine 3, and a waste heat recovery system 9 associated with the internal combustion engine3. The vehicle furthermore comprises a cooling system 71 associated with the internalcombustion engine 3 and connected to the waste heat recovery system 9. The vehicle mayfurther comprise a transmission 5 connected to the driving wheels 7 ofthe vehicle 1. The vehicle1 may be a heavy vehicle, e.g. a truck as herein illustrated or a bus. The vehicle may alternatively be a passenger car. Furthermore, the vehicle may be a hybrid vehicle comprising an electric 16machine (not shown) in addition to the combustion engine 3. The vehicle may alternatively be a marine vessel, such as a ship.
Figure 2 schematically shows an integrated system comprising a waste heat recovery system 9and cooling system 71 associated with a combustion engine 3 of a vehicle 1 according to an embodiment ofthe invention.
The waste heat recovery system 9 comprises a working fluid pump 11; an evaporator 13; anexpander 15, here shown as a turbine; a condenser 17; and a receiver tank 27 for working fluid.Pump out|et line 19 connects the pump 11 to the evaporator 13. Evaporator out|et line 21connects the evaporator 13 to the expander 15. Expander out|et line 23 connects the expander15 to the condenser 17. Condenser out|et line 25 connects the condenser to the working fluidpump 11, and thus completes the working fluid circuit. The receiver tank has an inlet 29connected to the condenser out|et line 25 by receiver inlet line 33, and an out|et 31 connectedto the condenser out|et line 25 by receiver out|et line 37. The junction 39 of the receiver out|etline 37 with the condenser out|et line 25 is arranged downstream of the junction 35 of thereceiver inlet line 37 with the condenser out|et line 25. Flow regulating means 57 and 59 arearranged in the receiver inlet line 33 and receiver out|et line 37 respectively. A further flow regulating means 61 is arranged in the condenser out|et line 25 between junctions 35 and 39.
The evaporator 13 is arranged for heat exchange between the working fluid and a heat source(not shown) associated with the combustion engine. The condenser 17 of the waste heatrecovery system 9 is connected to the engine cooling system 71. Here the condenser coolingsystem is illustrated as a dedicated condenser cooling loop comprising condenser inlet line 107and condenser return line 105, but alternative arrangements are possible. Alternatively, thecondenser cooling system may be a cooling system entirely separate to the engine cooling system 71.
During routine operation the working fluid in the waste heat recovery system is pumped fromlow pressure to high pressure by the working fluid pump 11 and enters the evaporator 13. Theworking fluid is thereby heated by the heat source (not shown) connected to the evaporator 13and the working fluid is evaporated. The working fluid vapour is then expanded in the expander15 whereby mechanical work is produced and the temperature and the pressure of the vapour is decreased. The mechanical work may for example be transferred to the transmission 5 of the 17vehicle as illustrated, and may thus be used to propel the vehicle. The working fluid vapourthereafter enters the condenser 17 where condensation through heat exchange between thevapour and the coolant fluid of the cooling system 71 brings the working fluid back to its initialliquid state. The working fluid is then transported to receiver tank 27 via tank inlet 29, orconveyed directly to working fluid pump 11, depending on the status of flow regulating means57, 59 and 61. The receiver tank 27 allows liquid working fluid to separate from working fluidvapour, and the liquid working fluid harboured in the receiver tank is thus stored in a form readyfor further pumping around the WHR circuit. Overall, the heat source (e.g. exhaust gas) providesthe energy entering the waste heat recovery system 9 and the energy leaves the waste heatrecovery system 9 as mechanical work via the expander 15 and as heat via the cooling system 71. ln some circumstances the condenser 17 is unable to provide sufficient cooling power in orderto sufficiently subcool the working fluid leaving the condenser. The present invention addressesthis problem by allowing working fluid harboured in receiver tank 27 to be vaporized, thusincreasing the condensation pressure and condensation temperature at the outlet of the condenser 17.
To this end, the receiver tank 27 is equipped with a heater 41, and the heater 41 is heated using a flow of hot coolant fluid from the engine cooling system 71.
The engine cooling system 71 comprises a coolant pump 95 arranged to circulate a coolant fluidthrough the cooling system, an engine outlet channel 74 arranged to collect hot coolant fluidhaving passed through the combustion engine 3, a radiator 73 arranged for cooling the coolantfluid having passed through the combustion engine 3, and a radiator return line 75 forchannelling coolant fluid from the engine outlet channel 74 to the radiator 73. The coolant pump95 may be driven mechanically by the combustion engine 3, but it may also be electricallydriven, or at least controllable. The engine cooling system 71 further comprises a radiatorbypass line 101, a first valve unit 97 and a second valve unit 99. The first valve unit 97 is suitablyarranged to control the flow of coolant fluid through the radiator 73 and the bypass line 101respectively. The second valve unit 99 is suitably arranged to control the flow of coolant fluid passing through the condenser 17 of the waste heat recovery system 9. 18ln order to supply hot coolant fluid to the heater 41, a heater feed line 49 is arranged to channelcoolant fluid from the engine outlet channel 74 to an inlet 43 of the heater 41. A heater returnline 77 is arranged to channel working fluid having passed through the heater 41 back to theradiator return line 75. A heater feed valve 85 is arranged to controllably redirect coolant fluidflow from the engine outlet channel 74 to the heater feed line 49 as desired. lf coolant fluid isredirected through heater 41, working fluid contained in the receiving tank 27 will beevaporated, and the condensation pressure at the outlet of condenser 17 will be raised. Thisleads to a higher condensation temperature and a lesser need of cooling power in condenser17 in order to achieve subcooling, thereby ensuring that sufficient subcooling is provided by the condenser.
Figure 3 schematically illustrates another embodiment of the present invention. ln thisembodiment heater return line 77 is routed via a recuperator 55 arranged in the pump outletline 19 in order to pre-heat working fluid prior to entering evaporator 13. After passing throughthe recuperator 55, the working fluid is routed onwards towards the radiator return line 75 aspreviously. This embodiment allows the recovery of heat from the coolant fluid passing through the heater 41 and thus increases the potential output of the waste heat recovery system.
Another feature of this embodiment is the ability to channel coolant fluid between the heaterfeed line 49 and heater return line 77 without passing through the heater 41. This is achievedby arranging a heater by-pass line 79 between the heater feed line 49 and heater return line 77.A controllable heater by-pass valve 83 directs the flow of coolant fluid through the heater 41 orbypass line 79. Such an arrangement permits the passage of coolant fluid through the recuperator 55 without it necessarily having previously passed through the heater 41. lt can further be seen in this embodiment that instead of a heater feed valve to direct flow tothe heater inlet line 49, a heater feed pump 87 is used instead. Having a dedicated pump toprovide a flow of coolant fluid through the heater 41 and/or recuperator 55 allows a flow ofcoolant through the heater and/or recuperator even whenever the coolant pump 95 is switched off.
Figure 4 schematically illustrates a further embodiment of the present invention. ln thisembodiment, the heater 41 and recuperator 55 are arranged in separate feed loops. The heater 41 is arranged in a heater feed loop comprising a heater feed line 49, heater 41, and heater 19return line 77. The heater feed loop draws coolant fluid from the engine outlet channel 74 andreturns the coolant to the engine outlet channel 74 after having passed through the heater 41.A heater feed pump 87 is arranged in the heater return line 77 to be able to drive the flow ofcoolant fluid through the heater 41, even if coolant is not circulating in the main coolant loop.The recuperator 55 is arranged in a recuperator feed loop comprising a recuperator feed line89, recuperator 55, and recuperator return line 91. The recuperator feed loop draws coolantfluid from the engine outlet channel 74 and returns the coolant to the radiator return line 75after hanving passed through the recuperator 55. A recuperator feed pump 93 is arranged inthe recuperatorfeed line 93 to be able to drive the flow of coolant fluid through the recuperator55, even if coolant is not circulating in the main coolant loop. By arranging the heater 41 andrecuperator 55 each in a separate loop with a dedicated pump, each ofthese components may be controlled independently of each other and the main cooling circuit.
Figure 5 is a flowchart schematically illustrating a method for controlling a waste heat recoverysystem according to the invention. Step s601 denotes the start of the method. ln step s603 thewaste heat recovery system is operated routinely, as described herein; i.e. working fluid is notrouted via the heater 41. Step s605 denotes a decision: is the condenser providing sufficientsubcooling of the working fluid? This may for example be determined using pressure and/ortemperature sensors located in the waste heat recovery system, or by determining the coolingpower of the condenser. lf the answer is YES, the method returns to step s603. lf the answer isNO the method proceeds to step s607. ln step s607 condensation pressure is increased in thecondenser by controllably directing a flow of coolant fluid from the engine outlet channel 74through the heater 41. This has the effect of increasing the condensation temperature of theworking fluid and ensuring that the condenser may provide sufficient subcooling. Step s609 denotes the end ofthe method.
On the contrary, if the condenser 17 is providing excessive subcooling, the temperatureprevailing in the receiver tank 27 should be decreased. This may for example be achieved bydirecting a flow of cooled working fluid from the condenser 17 through the receiver tank 27 in order to lower the temperature in the receiver tank 27.
Figure 6 is a flowchart schematically illustrating a method for shutting down a waste heat recovery system according to the invention. The method is performed during a shutdown phase of the waste heat recovery system in order to ensure that gaseous working liquid is isolated inthe receiver tank 27 and that the rest of the system is filled with liquid working fluid. Liquidgathers in the cooler parts ofthe WHR system and vapour gathers in the hotter parts. Therefore,in order to localize vaporized working fluid to the receiver tank 27, working fluid should becirculated and the receiver tank 27 should be heated until it is the hottest part of the WHRsystem. Step s701 denotes the start of the method. ln step s703 working fluid is circulatedaround the waste heat recovery system via heater 41 in order to heat receiver tank 27. Steps705 denotes a decision: does vaporized working fluid remain in the main waste heat recoverycircuit, that is to say all waste heat recovery components with the exception of the receivertank? lf the answer is YES, the method returns to step s703. lf the answer is NO the methodproceeds to step s707. ln step s707 the receiver tank is isolated by closing the first controllableflow regulating means 57 and second controllable flow regulating means 59, such that workingfluid contained in the main waste heat recovery circuit has a temperature below a condensationtemperature of the working fluid at ambient pressure, i.e. is liquid. The working fluid nowisolated in the receiver tank will gradually cool, leading to the generation of sub-atmosphericpressures in the receiver tank. However, the receiver tank may easily be provided with sealsable to withstand such low pressures. Other WHR components are much more difficult to sealeffectively against sub-atmospheric pressures, especially the expander, so by limiting theoccurrence of such pressures to the receiver tank, the design and construction of the WHRsystem is simplified. ln step s709 the working fluid pump is shut off. Step s711 denotes the end of the method.

Claims (15)

CLAll\/IS
1. A waste heat recovery system (9) for a vehicle (1), the waste heat recovery systemcomprising: a working fluid pump (11); an evaporator (13); an expander (15); a condenser (17); a pump outlet line (19) arranged to channel working fluid from the working fluid pump tothe evaporator; an evaporator outlet line (21) arranged to channel working fluid from the evaporator tothe expander; an expander outlet line (23) arranged to channel working fluid from the expander to thecondenser; a condenser outlet line (25) arranged to channel working fluid from the condenser to theworking fluid pump; a receiver tank (27) comprising a tank inlet (29) and a tank outlet (31), a tank inlet line (33) arranged to channel working fluid from a first junction (35) in thecondenser outlet line to the tank inlet; and a tank outlet line (37) arranged to channel working fluid from the tank outlet to a secondjunction (39) in the condenser outlet line, wherein the second junction is arrangedbetween the first junction and the working fluid pump; wäereiwcharacteršzecš in that the receiver tank (ggähas a substantially constant inner volume and is equipped with a heater (41) having a heater inlet (43) adapted to be fluidly connectable with an engine cooling system (71), and wherein the heater (41) is arranged to 'r “' 'r transfer teeat from a coolant fluid in the heater (lift) to a working fluid in the receiver tank (27).
2. An integrated system for a vehicle, the integrated system comprising a waste heatrecovery system and an engine cooling system, whereinthe waste heat recovery system comprises: a working fluid pump (11); an evaporator (13); an expander (15); a condenser (17); a pump outlet line (19) arranged to channel working fluid from the working fluid pump tothe evaporator; an evaporator outlet line (21) arranged to channel working fluid from the evaporator tothe expander; an expander outlet line (23) arranged to channel working fluid from the expander to thecondenser; a condenser outlet line (25) arranged to channel working fluid from the condenser to theworking fluid pump; a receiver tank (27) comprising a tank inlet (29) and a tank outlet (31); a tank inlet line (33) arranged to channel working fluid from a first junction (35) in thecondenser outlet line to the tank inlet; and a tank outlet line (37) arranged to channel working fluid from the tank outlet to a secondjunction (39) in the condenser outlet line, wherein the second junction is arrangedbetween the first junction and the working fluid pump; wherein the engine cooling system (71) comprises: a radiator (73); an engine outlet channel (74) arranged to collect coolant fluid exiting an engine; and a radiator return line (75) arranged to channel coolant fluid from the engine outletchannel to the radiatorjjåj; ttlwarattterízetå in that the receiver tank (27) Ewas a suåëstarttâalšv constanï' inner volurne arifi is equipped with a heater (41) having a heater inlet (43) arranged in fluid connection with the engine outletchannel via a heater feed line (49), wherein the heater feed line is arranged tochannel coolant fluid from the engine outlet channel to the heater inletjíljfi, and whereinthe heater gßgílis arranged to transfer hggifrom coolant fluid in the heater (41) to working fluid in the receiver tank (27).
3. The integrated system according to claim 2, wherein it comprises 3a heater return line (77) which is arranged to channel coolant fluid from an outlet of the heater to the engine outlet channel or radiator return line.
4. The integrated system according to claim 3, wherein it comprisesa recuperator (55) which is arranged to facilitate heat transfer from coolant fluid in the heater return line to working fluid in the pump outlet line.
5. The integrated system according to any claim 4, wherein it comprises a heater by-pass line (79) which is arranged to channel coolant fluid from the heater feedline to the heater return line, wherein the heater by-pass line forms a junction (81) withthe heater return line at a point between the heater and the recuperator; and a heater by-pass valve (83) which is arranged at a junction of the heater by-pass line andthe heater feed line, and is which arranged to controllably redirect a flow of coolant fluid from the heater feed line to the heater by-pass line.
6. The integrated system according to any one of claims 2-5, wherein it comprisesa heater feed valve (85) which is arranged at a junction of the heater feed line and theengine outlet channel, and which is arranged to controllably redirect a flow of coolant fluid from the engine outlet channel to the heater feed line.
7. The integrated system according to any one of claims 2-5, wherein it comprisesa heater feed pump (87) which is arranged in the heater feed line or the heater returnline, and which is arranged to controllably direct a flow of coolant fluid from the engine outlet channel to the heater feed line.
8. The integrated system according to any one of claims 2-7, wherein it comprisesa recuperator (55) which is arranged to facilitate heat transfer from coolant fluid in the engine outlet channel to working fluid in the pump outlet line.
9. The integrated system according to claim 8, wherein it comprises a recuperator feed line (89) which is arranged to channel coolant fluid from the engineoutlet channel to the recuperator; a recuperator return line (91) which is arranged to channel coolant fluid from the recuperator to the engine outlet channel or radiator return line; and
10.5 _
11.10
12.
13.
14.
15. 4a recuperator feed pump (93) which is arranged in the recuperator feed line orrecuperator return line, and which is arranged to controllably direct a flow of coolant fluid from the engine outlet channel to the recuperator feed line. The integrated system according to any one of claims 2-9, wherein it comprisesa first controllable flow restricting means (57) which is arranged in the tank inlet line; and a second controllable flow restricting means (59) which is arranged in the tank outlet line. The integrated system according to any one of claims 2-10, wherein it comprisesa third controllable flow restricting means (61) which is arranged in the condenser outlet line between the first junction and the second junction. The integrated system according to any one of claims 2-11, wherein the waste heat recovery system is a subcooler-free system. A method for controlling an integrated system according to any one of claims 2-12, themethod comprising a step of increasing condensation pressure in the condenser (17) bycontrollably directing a flow of coolant fluid from the engine outlet channel (74) through the heater (41). A method for shutting down an integrated system according to claim 10, the methodcomprising a step of, during a shutdown phase of the waste heat recovery system,isolating the receiver tank (27) by closing the first controllable flow restricting means (57)and second controllable flow restricting means (59), such that working fluid contained ina remainder of the waste heat recovery system has a temperature below a condensation temperature of the working fluid at ambient pressure. A vehicle (1) comprising a waste heat recovery system (9) according to claim 1, or an integrated system according to any one of claims 2-12.
SE1851320A 2018-10-25 2018-10-25 Waste heat recovery system comprising receiver tank heatable by coolant fluid SE542594C2 (en)

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DE112019004542.3T DE112019004542T5 (en) 2018-10-25 2019-09-27 Heat recovery system with a collecting tank heated by a coolant fluid
PCT/SE2019/050931 WO2020085968A1 (en) 2018-10-25 2019-09-27 Waste heat recovery system comprising receiver tank heatable by coolant fluid

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US11434810B2 (en) * 2021-02-04 2022-09-06 GM Global Technology Operations LLC Vehicle thermal management system including mechanically driven pump, rotary valve(s), bypass line allowing engine outlet coolant to bypass heat exchanger(s), or combinations thereof

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