SE1950709A1

SE1950709A1 - Thermal Management System, Method of Cooling a Condenser of a Waste Heat Recovery System, and Related Devices

Info

Publication number: SE1950709A1
Application number: SE1950709A
Authority: SE
Inventors: Ola Hall; Zoltan Kardos
Original assignee: Scania Cv Ab
Priority date: 2019-06-13
Filing date: 2019-06-13
Publication date: 2020-12-14
Also published as: SE543454C2; DE102020002880A1

Abstract

A thermal management system (1) for a vehicle (50) is disclosed. The system (1) comprises a waste heat recovery system (3) comprising an expander (5) and a condenser (7), and a power source cooling circuit (11) configured to cool a power source (9) of the vehicle (50). The power source cooling circuit (11) comprises a first coolant branch (17), a first bypass line (19) bypassing the first coolant branch (17), and a coolant reservoir (15) arranged in the first coolant branch (17). The system (1) comprises a condenser cooling circuit (21) configured to cool the condenser (7) using coolant from the coolant reservoir (15). The present disclosure further relates to a vehicle powertrain (40), a vehicle (50), a method (100) of cooling a condenser (7) of a waste heat recovery system (3), a computer program, a computerreadable medium (200), and a control arrangement (30).

Description

1 Thermal Management System, Method of Cooling a Condenser of aWaste Heat Recovery System, and Related Devices TECHNICAL FIELD The present disclosure relates to a thermal management system for a vehicle, wherein thesystem comprises a waste heat recovery system and a power source cooling circuitconfigured to cool a power source of the vehicle. The present disclosure further relates to avehicle powertrain, a vehicle, a method of cooling a condenser of a waste heat recoverysystem of a vehicle, a computer program, a computer-readable medium, and a control arrangement.

BACKGROUND Some vehicles are equipped with a waste heat recovery system utilizing waste heat of apower source of the vehicle for generating useful work. A waste heat recovery systemusually comprises an evaporator arranged to evaporate working media using waste heat andan expander arranged to provide useful work from evaporated working media. Moreover, awaste heat recovery system usually comprises a condenser arranged downstream of theexpander arranged to condense the working media before the working media is pumped tothe evaporator. ln order to condense the working media, the condenser must be cooled.

The expander may be connected to a driving shaft of the vehicle to provide the useful work inthe form of a driving torque to the driving shaft or may be arranged to power another device.ln this manner, the total energy efficiency of the vehicle is improved.

Waste heat recovery systems provide several advantages regarding the energy efficiency ofvehicles, but many challenges exist when it comes to converting waste heat into useful workin vehicles without significantly adding weight, cost, and complexity to the vehicle. Theefficiency of a waste heat recovery system partly depends on the temperature differencebetween the evaporator and the condenser. That is, if the condenser can be efficientlycooled, the efficiency of the waste heat recovery system can be improved.

However, during normal operation of a vehicle comprising a waste heat recovery system, theheat collected by the evaporator and the cooling demand of the condenser vary to a greatextent. That is, in high load situations, such as when the vehicle is driving uphill, or isperforming an overtake, a lot of heat can be generated in a short time and the heat collectedby the evaporator and the cooling demand of the condenser are significantly higher than during low load situations. l\/loreover, power source cooling circuits of modern vehicles face 2 challenges due to transient load conditions. As an example, some vehicles are equipped witha retarder arrangement used to augment or replace some of the functions of primary brakingarrangements, such as friction-based braking arrangements. Such retarder arrangementsare usually cooled by the power source cooling circuit of the vehicle. A lot of heat isgenerated in a short time when such a retarder arrangement is used which poses challengeson the design of the power source cooling circuit.

Furthermore, generally, on today"s consumer market, it is an advantage if products, such asvehicle systems and their associated components, have conditions and/or characteristicssuitable for being manufactured and assembled in a cost-efficient manner.

SUMMARYlt is an object of the present invention to overcome, or at least alleviate, at least some of theabove-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by a thermal managementsystem for a vehicle, wherein the system comprises a waste heat recovery systemcomprising an expander and a condenser, and a power source cooling circuit configured tocool a power source of the vehicle. The power source cooling circuit comprises a first coolantbranch, a first bypass line bypassing the first coolant branch, and a coolant reservoirarranged in the first coolant branch. The system comprises a condenser cooling circuit configured to cool the condenser using coolant from the coolant reservoir.

Since the system comprises a condenser cooling circuit configured to cool the condenserusing coolant from the coolant reservoir, a system is provided capable of obtaining a highdegree of cooling of the condenser also in transient load conditions. That is, in cases of asudden increase in cooling demand of the condenser, the coolant in the coolant reservoir canensure a sufficient condensation temperature in the condenser. As a further result of thesefeatures, more time is available for controlling the waste heat recovery system to a newcontrol cycle in cases where the cooling demand of the condenser suddenly increases.

Moreover, since the power source cooling circuit comprises a first bypass line bypassing thefirst coolant branch, conditions are provided for directing coolant to the coolant reservoir in amanner ensuring a low temperature of coolant in the coolant reservoir. This because incases where the temperature of coolant is high upstream the first coolant branch, such as forexample when a retarder arrangement is used, more coolant can be directed to first bypass line so as to not increase the temperature of coolant in the coolant reservoir.

Furthermore, since the system can obtain a high degree of cooling of the condenser also intransient load conditions, the system provides conditions for a more efficient utilization ofenergy in a vehicle.

Moreover, since the system comprises a condenser cooling circuit configured to cool thecondenser using coolant from the coolant reservoir, a simple and efficient system is providedhaving conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Accordingly, a thermal management system is provided overcoming, or at least alleviating, atleast some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the power source cooling circuit comprises a flow control assembly configuredcontrol flow of coolant directed to the first coolant branch and/or to the first bypass line.Thereby, conditions are provided for directing coolant to the coolant reservoir in a manner ensuring a low temperature of coolant in the coolant reservoir.

Optionally, the flow control assembly comprises a first valve. Thereby, a simple, reliable, andefficient arrangement is provided for directing coolant to the coolant reservoir in a manner ensuring a low temperature of coolant in the coolant reservoir.

Optionally, the system comprises a control arrangement configured to control the flow controlassembly. Thereby, an efficient arrangement is provided for controlling flow of coolantdirected to the first coolant branch and/or to the first bypass line.

Optionally, the power source cooling circuit comprises a heat exchanger, and wherein thefirst coolant branch comprises a branch inlet arranged downstream of the heat exchanger.Thereby, it is ensured that coolant having a low temperature is directed to the coolant reservoir.

Optionally, the power source cooling circuit comprises a second bypass line bypassing theheat exchanger and a second valve configured to direct coolant to the heat exchanger and/orto the second bypass line, and wherein the second bypass line comprises an outlet arrangeddownstream of the branch inlet in the power source cooling circuit. Thereby, it is ensured thatcoolant having a low temperature is directed to the coolant reservoir.

Optionally, the control arrangement is further configured to control the second valve.Thereby, a more flexible thermal management system is provided having conditions forsupplying coolant having a further lower temperature to the coolant reservoir. This becausethe control arrangement may control the second valve to direct more coolant to the heatexchanger than what is needed given a current cooling demand of the power source so as tosupply coolant having a further lower temperature to the coolant reservoir.

Optionally, the control arrangement is configured to control the second valve and the flowcontrol assembly to obtain a low temperature of coolant in the coolant reservoir. Thereby, asystem is provided having conditions for a more efficient utilization of energy in a vehicle.

Optionally, the coolant reservoir comprises a first outlet and a first inlet each connected tothe condenser cooling circuit, and wherein the condenser cooling circuit comprises a coolantpump configured to pump coolant through the condenser cooling circuit. Thereby, a simple,reliable, and efficient arrangement is provided for cooling the condenser in an efficientmanner also in transient load conditions. Moreover, conditions are provided for controllingthe cooling of the condenser, and thus also the condensation rate thereof, simply bycontrolling the pumping rate of the coolant pump.

Optionally, the system comprises a control arrangement configured to control a pumping rateof the coolant pump based on the temperature of coolant in the coolant reservoir and acooling demand of the condenser. Thereby, a simple, reliable, and efficient system isprovided capable of obtaining a high degree of cooling of the condenser also in transient loadconditions.

Optionally, the coolant accommodating capacity of the coolant reservoir is at least 15 % ofthe total coolant accommodating capacity of the power source cooling circuit. Thereby, it isensured that the coolant in the coolant reservoir can obtain a sufficient condensationtemperature in the condenser in cases of a sudden increase in cooling demand of thecondenser. Furthermore, it is ensured that sufficient time is available for controlling the wasteheat recovery system to a new control cycle in cases of sudden increases in the coolingdemand of the condenser.

Optionally, the coolant accommodating capacity of the coolant reservoir is at least 5 litres, orat least 7 litres. Thereby, it is ensured that the coolant in the coolant reservoir can obtain a sufficient condensation temperature in the condenser in cases of a sudden increase in cooling demand of the condenser. Furthermore, it is ensured that sufficient time is availablefor controlling the waste heat recovery system to a new control cycle in cases of suddenincreases in the cooling demand of the condenser.

According to a second aspect of the invention, the object is achieved by a vehicle powertraincomprising a power source configured to provide motive power to a vehicle comprising thepowertrain, wherein the powertrain comprises a thermal management system according to some embodiments of the present disclosure.

Since the vehicle powertrain comprises a thermal management system according to someembodiments, a simple and efficient powertrain is provided capable of converting waste heatinto useful work also in case of transient load conditions.

Accordingly, a vehicle powertrain is provided overcoming, or at least alleviating, at leastsome of the above-mentioned problems and drawbacks. As a result, the above-mentionedobject is achieved.

According to a third aspect of the invention, the object is achieved by a vehicle comprising apowertrain according to some embodiments of the present disclosure.

Since the vehicle comprises a powertrain according to some embodiments, a vehicle isprovided having a powertrain capable of converting waste heat into useful work also in caseof transient load conditions.

Accordingly, a vehicle is provided overcoming, or at least alleviating, at least some of theabove-mentioned problems and drawbacks. As a result, the above-mentioned object isachieved.

According to a fourth aspect of the invention, the object is achieved by a method of cooling acondenser of a waste heat recovery system of a vehicle, wherein the vehicle comprises athermal management system comprising: - the waste heat recovery system comprising the condenser and an expander, and - a power source cooling circuit configured to cool a power source of the vehicle,wherein the power source cooling circuit comprises: - a first coolant branch, - a first bypass line bypassing the first coolant branch, and 6 - a coolant reservoir arranged in the first coolant branch, and wherein the method comprises: - selectively directing at least a portion of coolant flow to the first coolant branch,and - cooling the condenser using coolant from the coolant reservoir.

Since the method comprises the steps of selectively directing at least a portion of coolantflow to the first coolant branch, and cooling the condenser using coolant from the coolantreservoir, a method is provided capable of obtaining a high degree of cooling of thecondenser also in transient load conditions. That is, in cases of a sudden increase in coolingdemand of the condenser, the coolant in the coolant reservoir can ensure a sufficientcondensation temperature in the condenser. As a further of these features, more time isavailable for controlling the waste heat recovery system to a new control cycle in cases ofsudden increases in the cooling demand of the condenser.

Moreover, since the power source cooling circuit comprises a first bypass line bypassing thefirst coolant branch, conditions are provided for directing coolant to the coolant reservoir in a manner ensuring a low temperature of coolant in the coolant reservoir.

Furthermore, since the method can obtain a high degree of cooling of the condenser also intransient load conditions, the method provides conditions for a more efficient utilization ofenergy in a vehicle.

Accordingly, a method is provided overcoming, or at least alleviating, at least some of theabove-mentioned problems and drawbacks. As a result, the above-mentioned object isachieved.

Optionally, the method comprises the step of:- selectively directing at least a portion of coolant flow to the first coolant branch to obtain a low temperature of coolant in the coolant reservoir.

Thereby, a method is provided having conditions for further improving the utilization ofenergy in a vehicle.

Optionally, the coolant reservoir comprises a first outlet and a first inlet each connected tothe condenser cooling circuit, and wherein the step of cooling the condenser comprises thestep of: 7 - pumping coolant through the condenser cooling circuit.

Thereby, a simple, reliable, and efficient method is provided for cooling the condenser in anefficient manner also in transient load conditions. l\/loreover, conditions are provided forcontrolling the cooling of the condenser, and thus also the condensation rate thereof, simplyby controlling the pumping rate of the coolant pump.

Optionally, the step of pumping coolant comprises the step of: - pumping coolant through the condenser cooling circuit with a pumping ratebased on the temperature of coolant in the coolant reservoir and a coolingdemand of the condenser.

Thereby, a simple, reliable, and efficient method is provided capable of obtaining a highdegree of cooling of the condenser also in transient load conditions.

According to a fifth aspect of the invention, the object is achieved by a computer programcomprising instructions which, when the program is executed by a computer, cause thecomputer to carry out the method according to some embodiments of the present disclosure.Since the computer program comprises instructions which, when the program is executed bya computer, cause the computer to carry out the method according to some embodiments, acomputer program is provided which provides conditions for overcoming, or at leastalleviating, at least some of the above-mentioned drawbacks.

According to a sixth aspect of the invention, the object is achieved by a computer-readablemedium comprising instructions which, when executed by a computer, cause the computer tocarry out the method according to some embodiments of the present disclosure. Since thecomputer-readable medium comprises instructions which, when the program is executed bya computer, cause the computer to carry out the method according to some embodiments, acomputer-readable medium is provided which provides conditions for overcoming, or at leastalleviating, at least some of the above-mentioned drawbacks.

According to a seventh aspect of the invention, the object is achieved by a controlarrangement configured to carry out the method according to some embodiments of thepresent disclosure. Since the control arrangement is configured to carry out the methodaccording to some embodiments, a control arrangement is provided which providesconditions for overcoming, or at least alleviating, at least some of the above-mentioneddrawbacks.

Further features of, and advantages with, the present invention will become apparent whenstudying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of the invention, including its particular features and advantages, will bereadily understood from the example embodiments discussed in the following detaileddescription and the accompanying drawings, in which: Fig. 1 schematically illustrates a powertrain, according to some embodiments, Fig. 2 illustrates a vehicle, according to some embodiments, Fig. 3 illustrates a method of cooling a condenser of a waste heat recovery system of avehicle, and Fig. 4 illustrates computer-readable medium, according to some embodiments.

DETAILED DESCRIPTION Aspects of the present invention will now be described more fully. Like numbers refer to likeelements throughout. Well-known functions or constructions will not necessarily be describedin detail for brevity and/or clarity.

Fig. 1 schematically illustrates a powertrain 40, according to some embodiments. Thepowertrain 40 comprises a power source 9 configured to provide motive power to a vehiclecomprising the powertrain 40. According to the illustrated embodiments, the power source 9is an internal combustion engine, and may be for example a compression ignition engine,such as a diesel engine, or an Otto engine with a spark-ignition device, wherein the Ottoengine may be configured to run on gas, petrol, alcohol, similar fuels, or combinationsthereof. According to further embodiments, the power source 9, as referred to herein, may beanother type of power source, such as an electric propulsion system, a fuel cell, or the like.

The powertrain 40 comprises a thermal management system 1, according to someembodiments. As is further explained herein, the thermal management system 1 isconfigured to manage heat in the powertrain 40. For the reason of brevity and clarity, thethermal management system 1 is in some places herein referred to as the system 1. Thethermal management system 1 comprises a waste heat recovery system 3. The waste heatrecovery system 3 comprises an expander 5 and a condenser 7. As is further explainedherein, according to the illustrated embodiments, the expander 5 is arranged to provideuseful work from heat generated by the power source 9.

According to the illustrated embodiments, the waste heat recovery system 3 comprises anexpansion tank 83, a working media pump 85, and a heat collector 81. The heat collector 81may also be referred to as a boiler or an evaporator. The working media pump 85 isarranged to pump working media through the waste heat recovery system 3. The heatcollector 81 may be in heat exchanging contact with a portion, or subsystem, of the powersource 9, and may be arranged to transfer heat from the portion or subsystem to the workingmedia of the waste heat recovery system 3.

As an example, the heat collector 81 may be arranged in an exhaust pipe of the powersource 9 to transfer heat from exhaust gasses to the working media of the waste heatrecovery system 3. ln the heat collector 81, the working media is heated to a temperature inwhich the working media evaporates from liquid phase into gaseous phase. The gaseousworking media is transferred to the expander 5. ln the expander 5, the temperature and thepressure of the working media is partially converted into useful work. According to theillustrated embodiments, a rotor of the expander 5 is mechanically connected to a shaft of thepower source 9, via a transmission 87. According to further embodiments, the expander 5may provide useful work in another manner, such as for example by driving an alternator producing electricity and/or by powering a secondary device.

The working media of the waste heat recovery system 3 flows out from the expander 5 andinto the condenser 7. ln the condenser 7, the temperature of the working media is furtherreduced, and gaseous working media is condensed back into liquid phase. From thecondenser 7, the working media is pumped to the heat collector 81 by the working mediapump 85. The expansion tank 83 acts as a reservoir holding working media and acts as apressure reservoir for the working media in the waste heat recovery system 3.

The thermal management system 1 further comprises a power source cooling circuit 11. Thepower source coolant circuit 11 is configured to cool the power source 9. The power sourcecooling circuit 11 comprises a heat exchanger 13, in the form of a radiator, and a coolantpump 49 arranged to pump coolant through the power source coolant circuit 11 so as to coolthe power source 9. l\/loreover, the power source cooling circuit 11 comprises an expansiontank reservoir 51. The expansion tank reservoir 51 is configured to allow the coolant and airin the power source cooling circuit 11 to expand with rising temperature and pressure. Theexpansion tank reservoir 51 may prevent venting and loss of coolant, by allowing coolant tobe sucked back into the power source cooling circuit 11 as the coolant in the power source cooling circuit 11 cools down. Moreover, the expansion tank reservoir 51 is arranged to vent the power source cooling circuit 11, is arranged to provide a less varying pressure to thecoolant pump 49, and is arranged to limit the maximum pressure in the power source cooling circuit 11.

The power source cooling circuit 11 further comprises a first coolant branch 17 and a firstbypass line 19 bypassing the first coolant branch 17. Moreover the power source coolantcircuit 11 comprises a coolant reservoir 15 arranged in the first coolant branch 17. Thecoolant reservoir 15 is a tank for holding coolant thereby acting as a reservoir, as is furtherexplained herein. The power source cooling circuit 11 comprises a flow control assembly 27.The flow control assembly 27 is configured control flow of coolant directed to the first coolantbranch 17 and to the first bypass line 19. The first coolant branch 17 comprises a branchinlet 17" arranged downstream of the heat exchanger 13.

According to the illustrated embodiments, the flow control assembly 27 comprises a firstvalve 27 arranged downstream of the branch inlet 17" of the first coolant branch 17. Whenthe first valve 27 is controlled towards a closed position, more coolant is directed to the firstcoolant branch 17, and when first valve 27 is controlled towards an open position, morecoolant is directed to the first bypass line 19. The power source cooling circuit 11 and the firstcoolant branch 17 may be arranged such that substantially no coolant is directed to the firstcoolant branch 17 when the first valve 27 is controlled to a fully open position, for examplecaused by a flow resistance through the first coolant branch 17.

According to further embodiments, the flow control assembly 27, as referred to herein, maycomprise another type of valve or arrangement, such as a three-way valve, configuredcontrol flow of coolant directed to the first coolant branch 17 and to the first bypass line 19, ora coolant pump arranged to control flow of coolant directed to the first coolant branch 17 andto the first bypass line 19. Such a coolant pump may for example be arranged in the firstcoolant branch 17, wherein the pumping rate of the coolant pump controls the flow of coolantdirected to the first coolant branch 17 and to the first bypass line 19.

The power source cooling circuit 11 comprises a second bypass line 23 bypassing the heatexchanger 13 and a second valve 25 configured to direct coolant to the heat exchanger 13and to the second bypass line 23. According to the illustrated embodiments, the secondvalve 25 is a three-way valve. According to further embodiments, the second valve maycomprise another type of valve or arrangement configured to direct coolant to the heatexchanger 13 and to the second bypass line 23. The second bypass line 23 comprises anoutlet 23" arranged downstream of the branch inlet 17" in the power source cooling circuit 11. 11 Thereby, it is ensured that coolant having a low temperature is directed to the coolantreservoir 15, as is further explained herein.

According to the illustrated embodiments, the first valve 27 of the flow control assembly 27and the second valve 25 are actively controllable valves. The thermal management system 1comprises a control arrangement 30 configured to control the flow control assembly 27 andthe second valve 25. As is further explained herein, the control arrangement 30 is configuredto control the second valve 25 and the flow control assembly 27 to obtain a low temperatureof coolant in the coolant reservoir 15. The control arrangement 30 may be configured tocontrol the second valve 25 based on a cooling demand of the power source 9 and on acooling demand of the condenser 7. Moreover, according to the embodiments illustrated inFig. 1, the powertrain 40 comprises a retarder oil cooler 48 configured to be cooled by thepower source cooling circuit 11 at a location upstream of the second valve 25. Therefore,according to these embodiments, the control arrangement 30 may also be configured tocontrol the second valve 25 based on a cooling demand of the retarder oil cooler 48.

When the cooling demand of one or more of these components 9, 15, 48 is high, the controlarrangement 30 may control the second valve 25 to direct more coolant to the heatexchanger 13 than what is directed to the second bypass line 23. ln this state, the controlarrangement 30 may control the flow control arrangement 27 based on a temperaturedifference between coolant flowing from the heat exchanger 13 and coolant in the coolantreservoir 15. lf the temperature of the coolant flowing from the heat exchanger 13 issignificantly higher than the temperature of coolant in the coolant reservoir 15, the controlarrangement may control the flow control assembly 27 to direct more coolant to the firstbypass line 19 than what is directed to the first coolant branch 17. lf the temperature of thecoolant flowing from the heat exchanger 13 is lower than the temperature of coolant in thecoolant reservoir 15, the control arrangement may control the flow control assembly 27 todirect more coolant to the first coolant branch 17 than what is directed to the first bypass line19.

When the cooling demand of all these components 9, 15, 48 is low, the control arrangement30 may control the second valve 25 to direct more coolant to the second bypass line 23 thanwhat is directed to the heat exchanger 13. However, in this state, the control arrangement 30may control the second valve 25 to direct a small flow of coolant to the heat exchanger 13and may control the flow control assembly 27 to direct the small flow of coolant from the heatexchanger 13 to the first coolant branch 17. ln this manner, coolant having a very lowtemperature is directed to the coolant reservoir 15. This because the small flow of coolant 12 through the heat exchanger 13 ensures an efficient cooling of the coolant. The coolanthaving a very low temperature stored in the coolant reservoir 15 can subsequently be usedto cool the condenser 7 if the cooling demand of the condenser 7 suddenly rises and/or if theflow demand through the heat exchanger 13 rises.

Furthermore, the arrangement 30 may be configured to control the flow control assembly 27to direct more coolant to the first coolant branch 17 when the cooling demand of thecondenser 7 is high, than when the cooling demand of the condenser 7 is low.

The thermal management system 1 comprises a condenser cooling circuit 21 configured tocool the condenser 7 using coolant from the coolant reservoir 15. Thereby, a high degree ofcooling of the condenser 7 can be obtained also in transient load conditions, as is furtherexplained herein.

The coolant reservoir 15 comprises a first outlet 21 " and a first inlet 21' each connected tothe condenser cooling circuit 21. That is, the coolant reservoir 15 is arranged in thecondenser cooling circuit 21, and the condenser cooling circuit 21 extends through the innervolume of the coolant reservoir 15. The condenser cooling circuit 21 comprises a coolantpump 29 configured to pump coolant through the condenser cooling circuit 21, and thus alsothrough the inner volume of the coolant reservoir 15.

According to the illustrated embodiments, the coolant reservoir 15 comprises a second inlet22' and a second outlet 22" each connected to the first coolant branch 17. That is, thecoolant reservoir 15 is also arranged in the first coolant branch 17, and the first coolantbranch 17 accordingly extends through the inner volume of the coolant reservoir 15.

Thus, according to the illustrated embodiments, the coolant reservoir 15 comprises two inlets21 ', 22' and two outlets 21 22" each connected the inner volume of the coolant reservoir15. Thereby, coolant flowing into the coolant reservoir 15 via the first and second inlets 21 ',22' can be mixed in the coolant reservoir 15 and can be pumped from the coolant reservoir15 via the first and second outlets 21 22" by the coolant pump 29, 49 of the respectivecircuit21,11.

The control arrangement 30 is configured to control a pumping rate of the coolant pump 29 ofthe condenser cooling circuit 21 based on the temperature of coolant in the coolant reservoir15 and a cooling demand of the condenser 7. The control arrangement 30 may input thecooling demand of the condenser 7 from the waste heat recovery system 3, and/or from a 13 control unit of the power source 9. The control arrangement 30 may input the temperature ofcoolant in the coolant reservoir 15 from a temperature sensor 53 arranged to sense the temperature of coolant in the coolant reservoir 15.

The coolant accommodating capacity of the coolant reservoir 15 may be at least 15 %, or atleast 22 % of the total coolant accommodating capacity of the power source cooling circuit11. As an alternative, or in addition, the coolant accommodating capacity of the coolantreservoir 15 may be at least 5 litres, or at least 7 litres.

Fig. 2 illustrates a vehicle 50, according to some embodiments. The vehicle 50 comprises apowertrain 40 comprising a power source 9 and a thermal management system 1 accordingto the embodiments illustrated in Fig. 1. The power source 9 is configured to provide motivepower to the vehicle 50, via wheels 57 of the vehicle 50. According to the illustratedembodiments, the vehicle 50 is a truck. However, according to further embodiments, thevehicle 50, as referred to herein, may be another type of manned or unmanned vehicle forland based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, or thelike.

Fig. 3 illustrates a method 100 of cooling a condenser of a waste heat recovery system of avehicle, wherein the vehicle comprises a thermal management system. The waste heatrecovery system and the thermal management system may be a waste heat recovery system3 and a thermal management system 1 according to the embodiments illustrated in Fig. 1.Moreover, the vehicle may be a vehicle 50 according to the embodiments illustrated in Fig. 2.Therefore, simultaneous reference is made to Fig. 1 - Fig. 3 below. The method 100 in Fig. 3is a method 100 of cooling a condenser 7 of a waste heat recovery system 3 of a vehicle 50,wherein the vehicle 50 comprises a thermal management system 1 comprising: - the waste heat recovery system 3 comprising the condenser 7 and an expander , and- a power source cooling circuit 11 configured to cool a power source 9 of thevehicle 50, wherein the power source cooling circuit 11 comprises: - a first coolant branch 17, - a first bypass line 19 bypassing the first coolant branch 17, and - a coolant reservoir 15 arranged in the first coolant branch 17, and wherein the method 100 comprises: - selectively directing 110 at least a portion of coolant flow to the first coolant branch 17, and 14 - cooling 120 the condenser 7 using coolant from the coolant reservoir 15.

As illustrated in Fig. 3, the method 100 may comprise the step of:- selectively directing 112 at least a portion of coolant flow to the first coolantbranch 17 to obtain a low temperature of coolant in the coolant reservoir 15.

According to some embodiments, the condenser cooling circuit 21 comprises a first inlet 21 "and a first outlet 21' each connected to the coolant reservoir 15, and wherein the step ofcooling 120 the condenser 7 comprises the step of: - pumping 122 coolant through the condenser cooling circuit 21.

As illustrated in Fig. 3, the step of pumping 122 coolant may comprise the step of: - pumping 124 coolant through the condenser cooling circuit 21 with a pumpingrate based on the temperature of coolant in the coolant reservoir 15 and acooling demand of the condenser 7. lt will be appreciated that the various embodiments described for the method 100 are allcombinable with the control arrangement 30 as described herein. That is, the controlarrangement 30 may be configured to perform any one of the method steps 110, 112, 120,122, 124 of the method 100.

Fig. 4 illustrates computer-readable medium 200 comprising instructions which, whenexecuted by a computer, cause the computer to carry out the method 100 according to someembodiments of the present disclosure.

According to some embodiments, the computer-readable medium 200 comprises a computerprogram comprising instructions which, when the program is executed by a computer, causethe computer to carry out the method 100 according to some embodiments.

One skilled in the art will appreciate that the method 100 of cooling a condenser of a wasteheat recovery system of a vehicle may be implemented by programmed instructions. Theseprogrammed instructions are typically constituted by a computer program, which, when it isexecuted in the control arrangement 30, ensures that the control arrangement 30 carries outthe desired control, such as the method steps 110, 112, 120, 122, 124 described herein. Thecomputer program is usually part of a computer program product 200 which comprises asuitable digital storage medium on which the computer program is stored.

The control arrangement 30 may comprise a calculation unit which may take the form ofsubstantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digitalsignal processing (digital signal processor, DSP), a Central Processing Unit (CPU), aprocessing unit, a processing circuit, a processor, an Application Specific Integrated Circuit(ASIC), a microprocessor, or other processing logic that may interpret and executeinstructions. The herein utilised expression "calculation unit" may represent a processingcircuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

The control arrangement 30 may further comprise a memory unit, wherein the calculationunit may be connected to the memory unit, which may provide the calculation unit with, forexample, stored program code and/or stored data which the calculation unit may need toenable it to do calculations. The calculation unit may also be adapted to store partial or finalresults of calculations in the memory unit. The memory unit may comprise a physical deviceutilised to store data or programs, i.e., sequences of instructions, on a temporary orpermanent basis. According to some embodiments, the memory unit may compriseintegrated circuits comprising silicon-based transistors. The memory unit may comprise e.g.a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile ornon-volatile storage unit for storing data such as e.g. ROIVI (Read-Only l\/lemory), PROIVI(Programmable Read-Only Memory), EPROIVI (Erasable PROIVI), EEPROIVI (ElectricallyErasable PROIVI), etc. in different embodiments.

The control arrangement 30 is connected to components of the vehicle 50 for receivingand/or sending input and output signals. These input and output signals may comprisewaveforms, pulses or other attributes which the input signal receiving devices can detect asinformation and which can be converted to signals processable by the control arrangement30. These signals may then be supplied to the calculation unit. One or more output signalsending devices may be arranged to convert calculation results from the calculation unit tooutput signals for conveying to other parts of the vehicle's control system and/or thecomponent or components for which the signals are intended. Each of the connections to therespective components of the vehicle 50 for receiving and sending input and output signalsmay take the form of one or more from among a cable, a data bus, e.g. a CAN (controllerarea network) bus, a l\/IOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection. 16 ln the embodiments illustrated, the thermal management system 1 comprises a controlarrangement 30 but might alternatively be implemented wholly or partly in two or more control arrangements or two or more control units.

Control systems in modern vehicles generally comprise a communication bus systemconsisting of one or more communication buses for connecting a number of electronic controlunits (ECUs), or controllers, to various components on board the vehicle. Such a controlsystem may comprise a large number of control units and taking care of a specific functionmay be shared between two or more of them. Vehicles of the type here concerned aretherefore often provided with significantly more control arrangements than depicted in Fig. 1,as one skilled in the art will surely appreciate.

The computer program product 200 may be provided for instance in the form of a data carriercarrying computer program code for performing at least some of the method steps 110, 112,120, 122, 124 according to some embodiments when being loaded into one or morecalculation units of the control arrangement 30. The data carrier may be, e.g. a CD ROIVIdisc, as is illustrated in Fig. 4, or a ROIVI (read-only memory), a PROIVI (programable read-only memory), an EPROIVI (erasable PROIVI), a flash memory, an EEPROIVI (electricallyerasable PROIVI), a hard disc, a memory stick, an optical storage device, a magnetic storagedevice or any other appropriate medium such as a disk or tape that may hold machinereadable data in a non-transitory manner. The computer program product may furthermorebe provided as computer program code on a server and may be downloaded to the controlarrangement 30 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems. lt is to be understood that the foregoing is illustrative of various example embodiments andthat the invention is defined only by the appended claims. A person skilled in the art willrealize that the example embodiments may be modified, and that different features of theexample embodiments may be combined to create embodiments other than those describedherein, without departing from the scope of the present invention, as defined by theappended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one ormore stated features, elements, steps, components, or functions but does not preclude thepresence or addition of one or more other features, elements, steps, components, functions,or groups thereof.

Claims

1. .

2. A thermal management system (1) for a vehicle (50), wherein the system (1) comprises:- a waste heat recovery system (3) comprising an expander (5) and a condenser (7),and- a power source cooling circuit (11) configured to cool a power source (9) of thevehicle (50),wherein the power source cooling circuit (11) comprises:- a first coolant branch (17),- a first bypass line (19) bypassing the first coolant branch (17), and- a coolant reservoir (15) arranged in thefirst coolant branch (17),and wherein the system (1) comprises a condenser cooling circuit (21)configured to cool the condenser (7) using coolant from the coolant reservoir (15).

3. . The system (1) according to claim 1, wherein the power source cooling circuit (11)

4. comprises a flow control assembly (27) configured control flow of coolant directed to thefirst coolant branch (17) and/or to the first bypass line (19).

5. The system (1) according to claim 2, wherein the flow control assembly (27) comprises afirst valve (27).

6. The system (1) according to claim 2 or 3, wherein the system (1) comprises a controlarrangement (30) configured to control the flow control assembly (27).

7. The system (1) according to any one of the preceding claims, wherein the power sourcecooling circuit (11) comprises a heat exchanger (13), and wherein the first coolantbranch (17) comprises a branch inlet (17') arranged downstream of the heat exchanger(13).

8. The system (1) according to claim 5, wherein the power source cooling circuit (11)comprises a second bypass line (23) bypassing the heat exchanger (13) and a secondvalve (25) configured to direct coolant to the heat exchanger (13) and/or to the secondbypass line (23), and wherein the second bypass line (23) comprises an outlet (23”)arranged downstream of the branch inlet (17') in the power source cooling circuit (11).

9. The system (1) according to claim 4 and 6, wherein the control arrangement (30) isfurther configured to control the second valve (25). 15. 18 The system (1) according to claim 7, wherein the control arrangement (30) is configuredto control the second valve (25) and the flow control assembly (27) to obtain a lowtemperature of coolant in the coolant reservoir (15). The system (1) according to any one of the preceding claims, wherein the coolantreservoir (15) comprises a first outlet (21 ”) and a first inlet (21”) each connected to thecondenser cooling circuit (21), and wherein the condenser cooling circuit (21) comprisesa coolant pump (29) configured to pump coolant through the condenser cooling circuit(21). The system (1) according to claim 9, wherein the system (1) comprises a controlarrangement (30) configured to control a pumping rate of the coolant pump (29) basedon the temperature of coolant in the coolant reservoir (15) and a cooling demand of thecondenser (7). The system (1) according to any one of the preceding claims, wherein the coolantaccommodating capacity of the coolant reservoir (15) is at least 15 % of the total coolantaccommodating capacity of the power source cooling circuit (11). The system (1) according to any one of the preceding claims, wherein the coolantaccommodating capacity of the coolant reservoir (15) is at least 5 litres, or at least 7litres. A vehicle powertrain (40) comprising a power source (9) configured to provide motivepower to a vehicle (50) comprising the powertrain (40), wherein the powertrain (40)comprises athermal management system (1) according to any one of the preceding claims. A vehicle (50) comprising a powertrain (40) according to claim 13. A method (100) of cooling a condenser (7) of a waste heat recovery system (3) of a vehicle (50), wherein the vehicle (50) comprises a thermal management system (1) comprising: - the waste heat recovery system (3) comprising the condenser (7) and an expander(5), and - a power source cooling circuit (11) configured to cool a power source (9) of thevehicle (50), 21. 19 wherein the power source cooling circuit (11) comprises:- a first coolant branch (17),- a first bypass line (19) bypassing the first coolant branch (17), and- a coolant reservoir (15) arranged in thefirst coolant branch (17),and wherein the method (100) comprises:- selectively directing (110) at least a portion of coolant flow to the first coolantbranch (17), and- cooling (120) the condenser (7) using coolant from the coolant reservoir (15). The method (100) according to claim 15, wherein the method (100) comprises the stepof:- selectively directing (112) at least a portion of coolant flow to the first coolantbranch (17) to obtain a low temperature of coolant in the coolant reservoir (15). The method (100) according to claim 15 or 16, wherein the coolant reservoir (15)comprises a first outlet (21 ”) and a first inlet (21') each connected to the condensercooling circuit (21), and wherein the step of cooling (120) the condenser (7) comprisesthe step of: - pumping (122) coolant through the condenser cooling circuit (21). The method (100) according to claim 17, wherein the step of pumping (122) coolant comprises the step of: - pumping (124) coolant through the condenser cooling circuit (21) with a pumping ratebased on the temperature of coolant in the coolant reservoir (15) and a coolingdemand of the condenser (7). A computer program comprising instructions which, when the program is executed by acomputer, cause the computer to carry out the method (100) according to any one of theclaims 15 -18. A computer-readable medium (200) comprising instructions which, when executed by acomputer, cause the computer to carry out the method (100) according to any one of theclaims 15 -18. A control arrangement (30) configured to carry out the method (100) according to anyone of the claims 15 -18.