SE1950710A1

SE1950710A1 - Method of Controlling Flow of Coolant, Vehicle Cooling System, and Related Devices

Info

Publication number: SE1950710A1
Application number: SE1950710A
Authority: SE
Inventors: Martin Mohlin; Ola Hall
Original assignee: Scania Cv Ab
Priority date: 2019-06-13
Filing date: 2019-06-13
Publication date: 2020-12-14
Also published as: BR102020011245A8; SE543426C2; DE102020002879A1; BR102020011245A2

Abstract

A method (100) of controlling flow of coolant through a heat exchanger (5) of a vehicle cooling system (6) is disclosed, wherein the vehicle cooling system (6) comprises the heat exchanger (5), a high temperature coolant circuit (7), a low temperature coolant circuit (9), and a flow control arrangement (1, 2, 3, 4, 21, 22). The method (100) comprises, in a switching procedure from a first cooling mode to a second cooling mode, restricting (110) the flowrate of coolant flowing through the heat exchanger (5) to obtain a temperature decrease of coolant flowing from the heat exchanger (5), and then allowing (120) full flow of coolant through the heat exchanger (5) into the low temperature coolant circuit (9). The present disclosure further relates to a computer program, a computer-readable medium (200), a control arrangement (30), a vehicle cooling system (6), and a vehicle (50).

Description

1 Method of Controlling Flow of Coolant, Vehicle Cooling System, and Related Devices TECHNICAL FIELD The present disclosure relates to a method of controlling flow of coolant through a heatexchanger of a vehicle cooling system. The present disclosure further relates to a computerprogram, a computer-readable medium, a control arrangement, a vehicle cooling system, and a vehicle.

BACKGROUND Vehicles comprise numerous components and systems which require cooling and theintroduction of electric propulsion systems in vehicles has increased this number ofcomponents and systems significantly. Each of these components and systems usually has aspecific optimal operational temperature. Moreover, some components and systems may betemperature sensitive and may become damaged if subjected to too high temperatures.Furthermore, some components and systems usually operate intermittently with periods ofinactivity and periods of high power operation. Obviously, during periods of inactivity there isno need for cooling and during periods of high power operation there is a high need forcooﬁng.

All these aspects pose problems on the design of vehicle cooling systems. A way to handlethese problems is to arrange one cooling system per system or component, or one coolingsystem per group of systems or components. However, such solutions add cost, complexity,and weight to the vehicle due to the large number of cooling systems.

Moreover, in general, on today's market, it is an advantage if products such as vehicles andtheir associated components and systems comprise different features and functions while theproducts have conditions and/or characteristics suitable for being manufactured andassembled 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 method of controllingflow of coolant through a heat exchanger of a vehicle cooling system, wherein the vehiclecooling system comprises the heat exchanger, a high temperature coolant circuit, a low 2 temperature coolant circuit, and a flow control arrangement configured to switch between afirst cooling mode, in which coolant of the high temperature coolant circuit is flowing throughthe heat exchanger, to a second cooling mode, in which coolant of the low temperaturecoolant circuit is flowing through the heat exchanger. The method comprises, in a switchingprocedure from the first cooling mode to the second cooling mode: - restricting the flowrate of coolant flowing through the heat exchanger to obtain a temperature decrease of coolant flowing from the heat exchanger, and then- allowing full flow of coolant through the heat exchanger into the low temperature coolant circuit.

Thereby, a simple and efficient method is provided which provides conditions for cooling twodifferent components or systems operating at different temperature levels using one heatexchanger without transferring heat energy from the high temperature coolant circuit to thelow temperature coolant circuit when switching from the from the high temperature coolantcircuit to the low temperature coolant circuit. This because the temperature decreaseobtained during the restriction of the flowrate of coolant flowing through the heat exchangerensures that a colder coolant is flowing into the low temperature coolant circuit when the full flow of coolant is allowed into the low temperature coolant circuit.

As a further result thereof, the method provides conditions for cooling two differentcomponents or systems operating at different temperature levels using one heat exchangerwithout damaging components or systems being cooled by the low temperature coolant circuit.

Moreover, since the method provides conditions for cooling two different components orsystems operating at different temperature levels using one heat exchanger, the methodprovides conditions for lowering manufacturing and assembling costs of vehicle coolingsystems.

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:- sensing or estimating the temperature of coolant flowing from the heatexchanger. 3 Thereby, conditions are provided for a more precise control of coolant through the heatexchanger so as to obtain a desired temperature decrease of coolant flowing from the heatexchanger.

Optionally, the step of restricting the flowrate comprises the step of:- restricting the flowrate of coolant based on the sensed or estimatedtemperature of coolant flowing from the heat exchanger.

Thereby, it can be ensured that a desired temperature decrease is obtained before allowingfull flow of coolant through the heat exchanger into the low temperature coolant circuit. As afurther result thereof, it can be ensured that components or systems cooled by the lowtemperature coolant circuit are not damaged when switching to the second cooling mode.

Optionally, the step of allowing full flow of coolant through the heat exchanger comprises the step of: - allowing full flow of coolant through the heat exchanger into the lowtemperature coolant circuit when the temperature of the coolant flowing from the heat exchanger is lower than a first threshold temperature.

Thereby, it can be ensured that components or systems cooled by the low temperaturecoolant circuit are not damaged when switching to the second cooling mode.

Optionally, the second coolant circuit is configured to cool a second vehicle component, andwherein the first threshold temperature is lower than a maximum coolant temperature of thesecond vehicle component. Thereby, it is ensured that the second vehicle component is notdamaged when switching to the second cooling mode.

Optionally, the step of allowing full flow of coolant through the heat exchanger comprises the step of: - allowing full flow of coolant through the heat exchanger into the lowtemperature coolant circuit when a temperature of the coolant flowing from theheat exchanger is substantially equal to the temperature of coolant in the low temperature coolant circuit.

Thereby, is ensured that substantially no heat energy is transferred from the hightemperature coolant circuit to the low temperature coolant circuit when switching from the first coolant mode to the second cooling mode. As a further result thereof, it can be ensured 4 that components or systems cooled by the low temperature coolant circuit are not damagedwhen switching to the second cooling mode.

Optionally, the vehicle cooling system comprises a fan configured to generate an airflow through the heat exchanger when activated, and wherein the method further comprises the step of: - activating the fan in the switching procedure from the first cooling mode to thesecond cooling mode.

Thereby, a quicker decrease in temperature is obtained of coolant flowing from the heatexchanger. As a result, a quicker switch from the first coolant mode to the second coolantmode can be obtained without damaging components cooled by the low temperature coolantcircuit and/or without transferring heat energy from the high temperature coolant circuit to thelow temperature coolant circuit upon switching from the first cooling mode to the secondcooling mode.

Optionally, the flow control arrangement comprises a number of valves, and wherein the stepof restricting the flowrate comprises the step of:- restricting the flowrate of coolant flowing through the heat exchanger using one or more valves of the number of valves.

Thereby, a simple, reliable, and efficient method is provided.

According to a second 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 third 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, a computer-readable medium is provided which provides conditions for overcoming, or at leastalleviating, at least some of the above-mentioned drawbacks.

According to a fourth aspect of the invention, the object is achieved by a control arrangementconfigured to control flow of coo|ant through a heat exchanger of a vehicle cooling system,wherein the vehicle cooling system comprises the heat exchanger, a high temperaturecoo|ant circuit, a low temperature coo|ant circuit, and a flow control arrangement configuredto switch between a first cooling mode, in which coo|ant of the high temperature coo|antcircuit is flowing through the heat exchanger, to a second cooling mode, in which coo|ant ofthe low temperature coo|ant circuit is flowing through the heat exchanger. The controlarrangement is configured to, in a switching procedure from the first cooling mode to thesecond cooling mode: - restrict the flowrate of coo|ant flowing through the heat exchanger to obtain a temperature decrease of coo|ant flowing from the heat exchanger, and then- allow full flow of coo|ant through the heat exchanger into the low temperature coo|ant circuit.

Thereby, a control arrangement is provided which provides conditions for cooling twodifferent components or systems operating at different temperature levels using one heatexchanger without transferring heat energy from the high temperature coo|ant circuit to thelow temperature coo|ant circuit when switching from the from the high temperature coo|antcircuit to the low temperature coo|ant circuit. This because the temperature decreaseobtained during the restriction of the flowrate of coo|ant flowing through the heat exchangerensures that a colder coo|ant is flowing into the low temperature coo|ant circuit when the full flow of coo|ant is allowed into the low temperature coo|ant circuit.

As a further result thereof, the control arrangement provides conditions for cooling twodifferent components or systems operating at different temperature levels using one heatexchanger without damaging components or systems being cooled by the low temperature coo|ant circuit.

Moreover, since the control arrangement provides conditions for cooling two differentcomponents or systems operating at different temperature levels using one heat exchanger,the control arrangement provides conditions for lowering manufacturing and assembling costs of vehicle cooling systems. 6 Accordingly, a control arrangement 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 fifth aspect of the invention, the object is achieved by a vehicle cooling systemcomprising a heat exchanger, a high temperature coolant circuit, a low temperature coolantcircuit, and a flow control arrangement configured to switch between a first cooling mode, inwhich coolant of the high temperature coolant circuit is flowing through the heat exchanger,to a second cooling mode, in which coolant of the low temperature coolant circuit is flowingthrough the heat exchanger. The vehicle cooling system further comprises a controlarrangement configured to control a flow of coolant through the heat exchanger. The controlarrangement is configured to, in a switching procedure from the first cooling mode to thesecond cooling mode: - restrict the flowrate of coolant flowing through the heat exchanger to obtain a temperature decrease of coolant flowing from the heat exchanger, and then- allow full flow of coolant through the heat exchanger into the low temperature coolant circuit.

Thereby, a vehicle cooling system is provided which provides conditions for cooling twodifferent components or systems operating at different temperature levels using one heatexchanger without transferring heat energy from the high temperature coolant circuit to thelow temperature coolant circuit when switching from the from the high temperature coolantcircuit to the low temperature coolant circuit. This because the temperature decreaseobtained during the restriction of the flowrate of coolant flowing through the heat exchangerensures that a colder coolant is flowing into the low temperature coolant circuit when the full flow of coolant is allowed into the low temperature coolant circuit.

As a further result thereof, the vehicle cooling system provides conditions for cooling twodifferent components or systems operating at different temperature levels using one heatexchanger without damaging components or systems being cooled by the low temperature coolant circuit.

Moreover, since the vehicle cooling system provides conditions for cooling two differentcomponents or systems operating at different temperature levels using one heat exchanger,a control arrangement is provided having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. 7 Accordingly, a vehicle cooling system 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 sixth aspect of the invention, the object is achieved by a vehicle comprising avehicle cooling system according to some embodiments of the present disclosure.

Since the vehicle comprises a vehicle cooling system according to some embodiments, avehicle is provided which provides conditions for overcoming, or at least alleviating, at leastsome of the above-mentioned drawbacks.

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.

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 vehicle cooling system, according to some embodiments,Fig. 2 illustrates a vehicle, according to some embodiments, Fig. 3 illustrates a method of controlling flow of coolant through a heat exchanger of a vehiclecooling system, and Fig. 4 illustrates a 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 vehicle cooling system 6, according to some embodiments.The vehicle cooling system 6 comprises a heat exchanger 5, a high temperature coolantcircuit 7, and a low temperature coolant circuit 9. The high temperature coolant circuit 7 is 8 configured to cool a first vehicle component 11 at a first temperature level and the lowtemperature coolant circuit 9 is configured to cool a second vehicle component 12 at asecond temperature level, wherein the second temperature level is lower than the first temperature level.

Purely as examples, according to some embodiments of the present disclosure, the firstvehicle component 11 may comprise an inverter of an electric propulsion system and thesecond vehicle component 12 may comprise a battery of the electric propulsion system.According to further embodiments, the first vehicle component 11 may comprise an electricmachine of an electric propulsion system and the second vehicle component 12 maycomprise an inverter of the electric propulsion system. According to still further embodiments,the first vehicle component 11 may comprise a combustion engine and the second vehiclecomponent 12 may comprise a condenser of a waste heat recovery system. According to stillfurther embodiments, the first vehicle component 11 may comprise a combustion engine andthe second vehicle component 12 may comprise a battery of an electric propulsion system.

Thus, according to embodiments of the present disclosure, during normal operation, the firstvehicle component 11 is cooled at a higher temperature level than the second vehiclecomponent 12. Moreover, according to some embodiments, the second vehicle component12 may be sensitive to too high coolant temperatures.

The vehicle cooling system 6 is capable of operating in a first cooling mode, in which coolantof the high temperature coolant circuit 7 is flowing through the heat exchanger 5 to cool thefirst vehicle component 11, and a second cooling mode, in which coolant of the lowtemperature coolant circuit 9 is flowing through the heat exchanger 5 to cool the secondvehicle component 12. ln the first cooling mode, no coolant is flowing from the lowtemperature coolant circuit 9 through the heat exchanger 5. Likewise, in the second coolingmode, no coolant is flowing from the high temperature coolant circuit 7 through the heatexchanger 5.

The vehicle cooling system 6 comprises a flow control arrangement 1, 2, 3, 4, 21, 22configured to switch between the first and second cooling modes. According to the illustratedembodiments, the flow control arrangement 1, 2, 3, 4, 21, 22 comprises a first valve 1, asecond valve 2, a third valve 3, a fourth valve 4, a first coolant pump 21 arranged to pumpcoolant through the high temperature coolant circuit 7, and a second coolant pump 22arranged to pump coolant through the low temperature coolant circuit 9. Moreover, thevehicle cooling system 6 comprises a control arrangement 30 configured to control the flow 9 control arrangement 1, 2, 3, 4, 21, 22, i.e. control the components 1, 2, 3, 4, 21, 22 of theflow control arrangement 1, 2, 3, 4, 21, 22.

According to the illustrated embodiments, the first valve 1 is located in the high temperaturecoolant circuit 7 and comprises one inlet 1a connected to the first coolant pump 21, a firstoutiet 1b connected to a bypass line 7' of the high temperature coolant circuit 7 bypassingthe heat exchanger 5, and a second outiet 1c connected to the heat exchanger 5. Thesecond valve 2 is located in the low temperature coolant circuit 9 and comprises one inlet 2aconnected to the second coolant pump 22, a first outiet 2b connected to a bypass line 9' ofthe low temperature coolant circuit 9 bypassing the heat exchanger 5, and a second outiet 2cconnected to the heat exchanger 5.

Moreover, according to the illustrated embodiments, as mentioned above, the vehicle coolingsystem 6 comprises a third valve 3. The third valve 3 comprises a first inlet 3a connected tothe second outiet 1c of the first valve 1 and a second inlet 3b connected to the second outiet2c of the second valve 2. l\/loreover, as mentioned above, according to the illustratedembodiments, the vehicle cooling system 6 comprises a fourth valve 4. The fourth valve 4comprises an inlet 4a connected to an outiet 5' of the heat exchanger 5, a first outiet 4bconnected to the high temperature coolant circuit 7, and a second outiet 4c connected to the low temperature coolant circuit 9.

According to the illustrated embodiments, when the vehicle cooling system 6 is operating inthe first cooling mode, the control arrangement 30 controls the first valve 1 such that aconnection is open between the inlet 1a and the second outiet 1c of the first valve 1, andcontrols the third valve 3 such a connection is open between the first inlet 3a and the outiet3c of the third valve 3. l\/loreover, in the first cooling mode, the control arrangement 30controls the fourth valve 4 such that a connection is open between the inlet 4a and the firstoutiet 4b of the fourth valve 4. Furthermore, in the in the first cooling mode, the controlarrangement 30 may operate the first coolant pump 21 and may control the second valve 2such that a connection is open between the inlet 2a and the first outiet 2b of the secondvalve 2. As an alternative, or in addition, in the second cooling mode, the controlarrangement 30 may cancel operation of the second coolant pump 22.

According to some embodiments of the present disclosure, the flow control arrangement 1, 2,3, 4, 21, 22 may comprise another number of valves 1, 2, 3, 4, and/or another types of valves1, 2, 3, 4 than depicted in Fig. 1. As an example, the third valve 3 may be omitted andwherein the control of flow from the high and low temperature circuits 7, 9 through the heat exchanger 5 is controlled by controlling the first and second valves 1, 2, and/or the fourthvalve 4. As another example, the fourth valve 4 may be omitted and may be replaced by oneor more flow restricting arrangements, such as a fixed restriction, one or more non returnvalves, or an arrangement, such as a loop or similar, that utilizes the density differencesbetween warm and cold coolant to avoid mixing of coolant having different temperatures.Moreover, the one or more of the first, second, third and fourth valve 1, 2, 3, 4 as describedherein may comprise another type of valve than a three-way valve, which valve may belocated at another position in the respective circuit 7, 9 than depicted in Fig. 1. Moreover,according to some embodiments of the present disclosure, the flow control arrangement 1, 2,3, 4, 21, 22 may comprise no valves. According to such embodiments, the flow from the highand low temperature circuits 7, 9 through the heat exchanger 5 may be controlled simply bycontrolling coolant pumps 21, 22 of the high and low temperature circuits 7, 9.

According to embodiments of the present disclosure, the control arrangement 30 isconfigured to, in a switching procedure from the first cooling mode to the second coolingmode, restrict the flowrate of coolant flowing through the heat exchanger 5 to obtain atemperature decrease of coolant flowing from the heat exchanger 5, and then allow full flowof coolant through the heat exchanger 5 into the low temperature coolant circuit 9. ln thismanner, it is ensured that the low temperature coolant circuit 9 is not supplied with coolanthaving too high temperature. The control arrangement 30 may be configured to perform a fullrestriction of the flowrate in which no coolant can flow through the heat exchanger 5, and/ormay be configured to perform a partial restriction of the flowrate in which some coolant canflow through the heat exchanger 5. ln this manner, the coolant in the heat exchanger 5 willhave a decreasing flow and this will thus give an increasing temperature drop. As is furtherexplained herein, the arrangement 30 may be configured to perform the restriction of theflowrate through the heat exchanger 5 based on a temperature difference between coolant inthe high temperature coolant circuit 7 and coolant in the low temperature coolant circuit 9.Moreover, according to some embodiments, the control arrangement 30 may be configuredto restrict the flow rate of coolant flowing through the heat exchanger 5 during a time-period.

According to some embodiments, in the switching procedure from the first cooling mode tothe second cooling mode, the control arrangement 30 may restrict the flow of coolant flowingfrom the high temperature coolant circuit 7 through the heat exchanger 5 using one or moreof the first valve 1, the third valve 3, and the fourth valve 4. As an alternative, or in addition,the control arrangement 30 may restrict the flow of coolant flowing from the high temperaturecoolant circuit 7 through the heat exchanger 5 by restricting the pumping rate of the firstcoolant pump 21. By restricting the flowrate of coolant flowing through the heat exchanger 5, 11 the coolant in the heat exchanger 5 will have time to cool down. Then, the controlarrangement 30 can allow full flow of coolant from the low temperature circuit 9 through theheat exchanger 5 by controlling the third valve 3 such a connection is open between thesecond inlet 3b and the outlet 3c of the third valve 3, controlling the fourth valve 4 such that aconnection is open between the inlet 4a and the second outlet 4c of the fourth valve 4, andcontrolling the second valve 2 such that a connection is open between the inlet 2a and thesecond outlet 2c of the second valve 2. The wording "allowing full flow", as used herein,means that the flow through the heat exchanger 5 is not intentionally restricted by the flowcontrol arrangement 1, 2, 3, 4, 21, 22 and that the pumping rate through the heat exchangeris set by the pumping rate of the second coolant pump 22, and/or the opening state of thesecond valve 2. Therefore, throughout this disclosure, the wording "allowing full flow" may bereplaced by the wording "cancelling the restriction of the flow rate".

According to some further embodiments of the present disclosure, the control arrangement30 may initiate the switch from the first cooling mode to the second cooling mode by allowingsome flow of coolant from the low temperature circuit 9 through the heat exchanger 5 butrestricting the flow of coolant from the low temperature circuit 9 through the heat exchanger 5such that a temperature decrease of coolant flowing from the heat exchanger 5 is obtained,and then allow full flow of coolant through the heat exchanger 5 into the low temperaturecircuit 9. ln such embodiments, the control arrangement 30 may thus initiate the switch fromthe first cooling mode to the second cooling mode by controlling the third valve 3 such that aconnection is open between the second inlet 3b and the outlet 3c of the third valve 3, controlthe fourth valve 4 such that a connection is open between the inlet 4a and the second outlet4c of the fourth valve 4, and control the second valve 2 such that a connection is openbetween the inlet 2a and the second outlet 2c of the second valve 2. As an alternative, or inaddition, the control arrangement 30 may initiate the switch from the first cooling mode to thesecond cooling mode by initiating operation of the second coolant pump 22. According tothese embodiments, the control arrangement 30 may restrict the flow of coolant from the lowtemperature circuit 9 through the heat exchanger 5 using one ore more of the third valve 3,the fourth valve 4a, and the second valve 2. As an alternative, or in addition, the controlarrangement 30 may restrict the flow of coolant flowing from the low temperature coolantcircuit 9 through the heat exchanger 5 by restricting the pumping rate of the second coolantpump 22.

According to the illustrated embodiments, the vehicle cooling system 6 comprises atemperature sensor 25 configured to sense the temperature of coolant flowing from the heatexchanger 5. The temperature sensor 25 may be arranged in an outlet line of the heat 12 exchanger 5, as is illustrated in Fig. 1, or may be arranged in the heat exchanger 5 to sensethe temperature of coolant in the heat exchanger 5. Moreover, as an alternative, or inaddition, the control arrangement 30 may be configured to estimate the temperature ofcoolant flowing from the heat exchanger 5.

According to embodiments of the present disciosure, the control arrangement 30 may restrictthe flowrate of coolant based on the sensed or estimated temperature of coolant flowing fromthe heat exchanger 5. As an example, the control arrangement 30 may allow full flow ofcoolant through the heat exchanger 5 into the low temperature coolant circuit 9 when thetemperature of the coolant flowing from the heat exchanger 5 is lower than a first thresholdtemperature. Thus, according to such embodiments, the control arrangement 30 may restrictflowrate of coolant through the heat exchanger 5 until the temperature of the coolant flowingfrom the heat exchanger 5 is lower than a first threshold temperature, and then allow full flowof coolant through the heat exchanger 5 into the low temperature coolant circuit 9. Thearrangement 30 may be configured to perform a full restriction of the flowrate through theheat exchanger 5 if the sensed or estimated temperature of coolant flowing from the heatexchanger 5 is significantly higher than the first threshold temperature, and may perform apartial restriction of the flowrate through the heat exchanger 5 if the sensed or estimatedtemperature of coolant flowing from the heat exchanger 5 is slightly higher than the firstthreshold temperature a temperature. According to these embodiments, the first thresholdtemperature may be lower than a maximum coolant temperature required by the second vehicle component 12.

According to some further embodiments of the present disciosure, the control arrangement30 may allow full flow of coolant through the heat exchanger 5 into the low temperaturecoolant circuit 9 when the sensed or estimated temperature of the coolant flowing from theheat exchanger 5 is substantially equal to the temperature of coolant in the low temperaturecoolant circuit 9. Thus, according to such embodiments, the control arrangement 30 mayrestrict flowrate of coolant through the heat exchanger 5 until the sensed or estimatedtemperature of the coolant flowing from the heat exchanger 5 is substantially equal to thetemperature of coolant in the low temperature coolant circuit 9, and then allow full flow ofcoolant through the heat exchanger 5 into the low temperature coolant circuit 9. According tothese embodiments, the control arrangement 30 may sense or estimate the temperature ofcoolant in the low temperature coolant circuit 9. Moreover, according to these embodiments,the control arrangement 30 may be configured to perform a full or partial restriction of theflowrate of coolant through the heat exchanger 5 until the sensed or estimated temperatureof the coolant flowing from the heat exchanger 5 is substantially equal to the temperature of 13 coolant in the low temperature coolant circuit 9, and then allow full flow of coolant through theheat exchanger 5 into the low temperature coolant circuit 9.

According to some embodiments of the present disclosure, the control arrangement 30 mayallow full flow of coolant through the heat exchanger 5 into the low temperature coolantcircuit 9 when it is estimated that substantially all coolant in heat exchanger 5 has beenreplaced with coolant from the low temperature coolant circuit 9.

According to the illustrated embodiments, vehicle cooling system 6 comprises a fan 15. Thefan 15 is configured to generate an airflow through the heat exchanger 5 when activated.According to some embodiments, the control arrangement 30 may be configured to activatethe fan 15 in the switching procedure from the first cooling mode to the second cooling mode.ln this manner, a quicker decrease in temperature is obtained of the coolant flowing from theheat exchanger 5. According to these embodiments, the control arrangement 30 may beconfigured to activate the fan 15 based on a temperature difference between coolant in thehigh temperature coolant circuit 7 and coolant in the low temperature coolant circuit 9.According to such embodiments, the control arrangement 30 may be configured to activatethe fan 15 in the switching procedure from the first cooling mode to the second cooling modeif the temperature difference between coolant in the high temperature coolant circuit 7 andcoolant in the low temperature coolant circuit 9 is above a threshold value. ln the first cooling mode, i.e. when the first vehicle component 11 is cooled by the heatexchanger 5, the second vehicle component 12 may be inactive, may operate at a powerlevel not requiring cooling, or may be cooled by a second heat exchanger (not shown).Likewise, in the second cooling mode, i.e. when the second vehicle component 12 is cooledby the heat exchanger 5, the first vehicle component 11 may be inactive, may operate at apower level not requiring cooling, or may be cooled by a third heat exchanger (not shown).

Fig. 2 illustrates a vehicle 50 according to some embodiments. The vehicle 50 comprises afirst vehicle component 11, a second vehicle component 12, and a vehicle cooling system 6according to the embodiments illustrated in Fig. 1. According to the illustrated embodiments,the first and second vehicle components 11, 12 form part of an electric propulsion system ofthe vehicle 50, wherein the electric propulsion system is configured to provide motive powerto the vehicle 50 via wheels 52 of the vehicle 50. According to the illustrated embodiments,the vehicle 50 is a truck. However, according to further embodiments, the vehicle 50, as referred to herein, may be another type of manned or unmanned vehicle for land or water 14 based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a ship, aboat, or the like.

Fig. 3 illustrates a method 100 of controlling flow of coolant through a heat exchanger of avehicle cooling system. The vehicle cooling system may be a vehicle cooling system 6according to the embodiments illustrated in Fig. 1. Therefore, below, simultaneous referenceis made to Fig. 1 and Fig. 3. The method 100 is a method 100 of controlling flow of coolantthrough a heat exchanger 5 of a vehicle cooling system 6,wherein the vehicle cooling system 6 comprises:- the heat exchanger 5,- a high temperature coolant circuit 7,- a low temperature coolant circuit 9, and- a flow control arrangement 1, 2, 3, 4, 21, 22 configured to switch between a firstcooling mode, in which coolant of the high temperature coolant circuit 7 is flowingthrough the heat exchanger 5, to a second cooling mode, in which coolant of the lowtemperature coolant circuit 9 is flowing through the heat exchanger 5,wherein the method 100 comprises, in a switching procedure from the first cooling mode tothe second cooling mode:- restricting 110 the flowrate of coolant flowing through the heat exchanger 5 to obtaina temperature decrease of coolant flowing from the heat exchanger 5, and then- allowing 120 full flow of coolant through the heat exchanger 5 into the low temperature coolant circuit 9.

As illustrated in Fig. 3, the method 100 may comprise:- sensing 105 or estimating 106 the temperature of coolant flowing from the heatexchanger 5. l\/loreover, as illustrated in Fig. 3, the step of restricting 110 the flowrate may comprise thestep of:- restricting 112 the flowrate of coolant based on the sensed or estimated temperatureof coolant flowing from the heat exchanger 5.

As illustrated in Fig. 3, the step of allowing 120 full flow of coolant through the heatexchanger 5 may comprise the step of:- allowing 122 full flow of coolant through the heat exchanger 5 into the lowtemperature coolant circuit 9 when the temperature of the coolant flowing from theheat exchanger 5 is lower than a first threshold temperature.

As illustrated in Fig. 3, the step of allowing 122 full flow of coolant through the heatexchanger 5 may comprise the step of:- allowing 123 full flow of coolant through the heat exchanger 5 into the lowtemperature coolant circuit 9 when the sensed or estimated temperature of thecoolant flowing from the heat exchanger 5 is lower than a first threshold temperature.

According to some embodiments, the second coolant circuit 9 is configured to cool a secondvehicle component 12. According to these embodiments, the first threshold temperature may be lower than a maximum coolant temperature of the second vehicle component 12.

As illustrated in Fig. 3, the step of allowing 120 full flow of coolant through the heatexchanger 5 may comprise the step of: - allowing 124 full flow of coolant through the heat exchanger 5 into the lowtemperature coolant circuit 9 when a temperature of the coolant flowing from the heatexchanger 5 is substantially equal to the temperature of coolant in the lowtemperature coolant circuit 9.

As illustrated in Fig. 3, the step of allowing 124 full flow of coolant through the heatexchanger 5 may comprise the step of: - allowing 125 full flow of coolant through the heat exchanger 5 into the lowtemperature coolant circuit 9 when the sensed or estimated temperature of thecoolant flowing from the heat exchanger 5 is substantially equal to the temperature ofcoolant in the low temperature coolant circuit 9.

As illustrated in Fig. 3, the method may comprise the step of:- sensing 126 or estimating 127 the temperature of coolant in the low temperaturecoolant circuit 9.

According to some embodiments, the vehicle cooling system 6 comprises a fan 15configured to generate an airflow through the heat exchanger 5 when activated, and whereinthe method 100 further comprises the step of:- activating 114 the fan 15 in the switching procedure from the first cooling mode to thesecond cooling mode. 16 According to some embodiments, the flow control arrangement 1, 2, 3, 4, 21, 22 comprises anumber of valves 1, 2, 3, 4, and wherein the step of restricting 110 the flowrate comprisesthe step of:- restricting 116 the flowrate of coolant flowing through the heat exchanger 5 using oneor more valves 1, 2, 3, 4 of the number of valves 1, 2, 3, 4. 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 105, 106, 110,112,114,116,120,122,123,124,125,126,and127 of the method 100.

Fig. 4 illustrates a 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 control|ing flow of coolant througha heat exchanger 5 of a vehicle cooling system 6 may be implemented by programmedinstructions. These programmed instructions are typically constituted by a computer program,which, when it is executed in the control arrangement 30, ensures that the controlarrangement 30 carries out the desired control, such as the method steps 105, 106, 110,112, 114, 116, 120, 122, 123, 124, 125, 126, 127 described herein. The computer program isusually part of a computer program product 200 which comprises a suitable digital storagemedium 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. 17 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. ln the embodiments illustrated, the vehicle cooling system 6 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. 18 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 105, 106,110, 112, 114, 116, 120, 122, 123, 124, 125, 126, and 127 according to some embodimentswhen being loaded into one or more calculation units of the control arrangement 30. Thedata carrier may be, e.g. a CD ROIVI disc, as is i||ustrated in Fig. 4, or a ROIVI (read-onlymemory), a PROIVI (programable read-only memory), an EPROIVI (erasable PROIVI), a flashmemory, an EEPROIVI (electrically erasable PROIVI), a hard disc, a memory stick, an opticalstorage device, a magnetic storage device or any other appropriate medium such as a diskor tape that may hold machine readable data in a non-transitory manner. The computerprogram product may furthermore be provided as computer program code on a server andmay be downloaded to the control arrangement 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.

Throughout this disclosure, the high temperature coolant circuit may also be referred to asthe first coolant circuit. Likewise, throughout this disclosure, the low temperature coolantcircuit may also be referred to as the second coolant circuit.

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. A method (100) of controlling flow of coolant through a heat exchanger (5) of a vehicle cooling system (6),wherein the vehicle cooling system (6) comprises: - the heat exchanger (5), - a high temperature coolant circuit (7), - a low temperature coolant circuit (9), and - a flow control arrangement (1, 2, 3, 4, 21, 22) configured to switch between afirst cooling mode, in which coolant of the high temperature coolant circuit (7) isflowing through the heat exchanger (5), to a second cooling mode, in whichcoolant of the low temperature coolant circuit (9) is flowing through the heatexchanger (5),and wherein the method (100) comprises, in a switching procedure from the first cooling mode to the second cooling mode: - restricting (110) the flowrate of coolant flowing through the heat exchanger (5)to obtain a temperature decrease of coolant flowing from the heat exchanger(5), and then - allowing (120) full flow of coolant through the heat exchanger (5) into the lowtemperature coolant circuit (9)The method (100) according to claim 1, wherein the method (100) comprises: - sensing (105) or estimating (106) the temperature of coolant flowing from theheat exchanger (5)_ The method (100) according to claim 2, wherein the step of restricting (110) the flowrate comprises the step of:- restricting (112) the flowrate of coolant based on the sensed or estimatedtemperature of coolant flowing from the heat exchanger (5)The method (100) according to any one of the preceding claims, wherein the step of allowing (120) full flow of coolant through the heat exchanger (5) comprises the step of:- allowing (122) full flow of coolant through the heat exchanger (5) into the lowtemperature coolant circuit (9) when the temperature of the coolant flowing fromthe heat exchanger (5) is lower than a first threshold temperatureThe method (100) according to claim 4, wherein the second coolant circuit (9) is configured to cool a second vehicle component (12), and wherein the first threshold 10 11. temperature is lower than a maximum coolant temperature of the second vehicle component (12)The method (100) according to any one of the preceding claims, wherein the step ofallowing (120) full flow of coolant through the heat exchanger (5) comprises the step of:- allowing (124) full flow of coolant through the heat exchanger (5) into the lowtemperature coolant circuit (9) when a temperature of the coolant flowing fromthe heat exchanger (5) is substantially equal to the temperature of coolant in the low temperature coolant circuit (9)The method (100) according to any one of the preceding claims, wherein the vehiclecooling system (6) comprises a fan (15) configured to generate an airflow through theheat exchanger (5) when activated, and wherein the method (100) further comprises thestep of: - activating (114) the fan (15) in the switching procedure from the first cooling mode to the second cooling modeThe method (100) according to any one of the preceding claims, wherein the flow controlarrangement (1, 2, 3, 4, 21, 22) comprises a number of valves (1, 2, 3, 4), and whereinthe step of restricting (110) the flowrate comprises the step of:- restricting (116) the flowrate of coolant flowing through the heat exchanger (5)using one or more valves (1, 2, 3, 4) of the number of valves (1, 2, 3, 4)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 1 - 8A 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 1 - 8A control arrangement (30) configured to control flow of coolant through a heatexchanger (5) of a vehicle cooling system (6),wherein the vehicle cooling system (6) comprises:- the heat exchanger (5),- a high temperature coolant circuit (7),- a low temperature coolant circuit (9), and 21 a flow control arrangement (1, 2, 3, 4, 21, 22) configured to switch between afirst cooling mode, in which coolant of the high temperature coolant circuit (7) isflowing through the heat exchanger (5), to a second cooling mode, in whichcoolant of the low temperature coolant circuit (9) is flowing through the heatexchanger (5), wherein the control arrangement (30) is configured to, in a switching procedure from the first cooling mode to the second cooling mode: restrict the flowrate of coolant flowing through the heat exchanger (5) to obtaina temperature decrease of coolant flowing from the heat exchanger (5), andthen allow full flow of coolant through the heat exchanger (5) into the lowtemperature coolant circuit (9)1

2. A vehicle cooling system (6) comprising: a heat exchanger (5), a high temperature coolant circuit (7), a low temperature coolant circuit (9), a flow control arrangement (1, 2, 3, 4, 21, 22) configured to switch between afirst cooling mode, in which coolant of the high temperature coolant circuit (7) isflowing through the heat exchanger (5), to a second cooling mode, in whichcoolant of the low temperature coolant circuit (9) is flowing through the heatexchanger (5), and a control arrangement (30) configured to control a flow of coolant through theheat exchanger (5), wherein the control arrangement (30) is configured to, in a switching procedure from the first cooling mode to the second cooling mode: restrict the flowrate of coolant flowing through the heat exchanger (5) to obtaina temperature decrease of coolant flowing from the heat exchanger (5), andthen allow full flow of coolant through the heat exchanger (5) into the lowtemperature coolant circuit (9). 1

3. A vehicle (50) comprising a vehicle cooling system (6) according to claim 12.