Patent Publication Number: US-2022234420-A1

Title: Thermal management system, powertrain, and vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage Patent Application (filed under 35 § U.S.C. 371) of PCT/SE2020/050600, filed Jun. 10, 2020 of the same title, which, in turn claims priority to Swedish Patent Application No. 1950848-0 filed Jul. 5, 2019 of the same title; the contents of each of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to a thermal management system for a vehicle. The present disclosure further relates to a powertrain for a vehicle, as well as a vehicle comprising a powertrain. 
     BACKGROUND OF THE INVENTION 
     Vehicles with an occupant compartment usually comprise a heating arrangement for heating the occupant compartment utilizing waste heat of a propulsion system of the vehicle. Due to environmental concerns, as well as economic concerns of customers, propulsion systems of modern vehicles have become more energy efficient meaning that less waste heat is available for heating the occupant compartment. 
     Some propulsion systems comprise an internal combustion engine, for example a compression ignition engine, such as a diesel engine, or an Otto engine, which generates excess heat during operation. However, many modern vehicles are equipped with a start-stop system arranged to automatically shut down and restart the internal combustion engine to reduce the amount of time the engine spends idling, thereby reducing fuel consumption and emissions. Moreover, these types of engines have become increasingly energy efficient meaning that the waste heat generated by the internal combustion engine may be insufficient for heating the occupant compartment to a desired level with a traditional heating arrangement. 
     Some vehicles comprise an electric propulsion system comprising an electric machine, power electronics, a battery, and the like. These components generate heat during operation which can be used to heat the occupant compartment. However, the amount of heat generated is significantly lower than what is generated by an internal combustion engine. Moreover, during periods of stand still, the maximum temperature of some components may be less than an optimum temperature for heating the occupant compartment. 
     Electric propulsion systems can be divided into the categories fully electric propulsion systems and hybrid electric propulsion systems. A fully electric propulsion system is arranged to purely operate on electricity and comprise no internal combustion engine. A hybrid electric propulsion system uses two or more distinct types of power, such as an internal combustion engine and an electric machine. Generally, an internal combustion engine has poor energy efficiency at lower power output levels and better energy efficiency at higher power output levels. An electric propulsion system usually has great energy efficiency at low power output levels and at high power output levels, but the storage of electric energy in the vehicle is usually insufficient for allowing longer time periods of operation at higher power output levels. 
     Therefore, some hybrid electric propulsion systems are configured to switch between electric propulsion and combustion engine propulsion in dependence of the load such that the electric propulsion system is operated in low load situations and the combustion engine is started and operated in higher load situations. Some hybrid electric propulsion systems are configured to allow simultaneous operation of the electric propulsion system and the combustion engine. The electric energy can be stored in batteries for use for propulsion of the vehicle. In this manner, the total energy efficiency of the vehicle can be improved, especially when driving in areas with many starts and stops, such as when driving in urban areas. 
     A further advantage of hybrid electric propulsion systems is that they can allow pure electric propulsion system in certain areas, such as in city centres, and other areas sensitive to emission of exhaust gases, and/or emission of noise. As understood from the above, in many cases, the waste heat generated by a hybrid electric propulsion system can be insufficient for heating the occupant compartment of the vehicle. Therefore, some hybrid electric propulsion systems are arranged to start the internal combustion engine when the heating demand of the occupant compartment is high and the available heat in the propulsion system is low to thereby increase the available heat in the propulsion system. Such a start-up of the internal combustion engine increases the consumption of fuel and increases emissions from the propulsion system. 
     Using a heat pump circuit between the propulsion coolant circuit and a heating circuit for the occupant compartment is an efficient and effective way of increasing the heat transfer from the propulsion system to the occupant compartment. However, as is the case with several other types of systems, a heat pump circuit has a narrow operational range in which it operates most efficiently and seasonal changes, temperature variations, and variations in heating demand of the occupant compartment put limitations on the efficiency of such a system. 
     Moreover, seasonal changes, temperature variations, and variations in heating demand of the occupant compartment put different requirements on such a system, which can be conflicting requirements. Furthermore, a propulsion system of a vehicle may comprise components sensitive to low or high temperatures. 
     Furthermore, generally, on today&#39;s consumer market, it is an advantage if products, such as vehicle systems and their associated components, have conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks. 
     According to a first aspect of the invention, the object is achieved by a thermal management system for a vehicle, wherein the vehicle comprises an occupant compartment and a propulsion system configured to provide motive power to the vehicle. The thermal management system a propulsion coolant circuit configured to cool at least a portion of the propulsion system, a heating circuit configured to heat the occupant compartment, and a heat pump circuit comprising a first evaporator in the propulsion coolant circuit and a condenser in the heating circuit. The propulsion coolant circuit comprises a connecting conduit connecting the propulsion coolant circuit to the heating circuit at a position upstream of the condenser. The propulsion coolant circuit further comprises a first return conduit configured to return coolant to the propulsion coolant circuit from the heating circuit at a position downstream of the condenser. The thermal management system further comprises a first valve configured to control flow of coolant through the connecting conduit. 
     Since the propulsion coolant circuit comprises the connecting conduit and the first valve configured to control flow of coolant through the connecting conduit, a more flexible and more controllable thermal management system is provided allowing the heating circuit to operate at a higher temperature level than the temperature level of the propulsion coolant circuit. 
     Accordingly, by controlling the first valve to hinder flow of coolant through the connecting conduit, the coolant of the propulsion coolant circuit bypasses the condenser and the heating circuit becomes isolated from the propulsion coolant circuit allowing the heating circuit to operate at a higher temperature level than the temperature level of the propulsion coolant circuit. Thereby, the heat pump circuit can transfer heat from the propulsion coolant circuit to the heating circuit in a more efficient manner for example during wintertime when the ambient temperature is low, and the heating demand of the occupant compartment is high. 
     Moreover, a thermal management system is provided in which the condenser can be cooled by the propulsion coolant circuit by controlling the first valve to allow flow of coolant through the connecting conduit, for example during summertime when the ambient temperature is higher, and the heating demand of the occupant compartment is lower. Furthermore, a thermal management system is provided in which the condenser can be used for heating components of the propulsion system when needed by controlling the first valve to allow flow of coolant through the connecting conduit. 
     Thus, due to these features, heat can be transferred to and from the propulsion system in a more efficient manner, meaning that conditions are provided for a more efficient utilization of energy in a vehicle comprising the thermal management system. Moreover, a thermal management system is provided capable of improving occupant compartment heating performance of a vehicle comprising the thermal management system. 
     Accordingly, a thermal management system is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved. 
     Optionally, the propulsion coolant circuit comprises a bypass line bypassing the connecting conduit, and wherein the first valve is controllable between a first state in which the first valve directs coolant through the connecting conduit and a second state in which the first valve directs coolant through the bypass line. Thereby, a simple and reliable control of flow of coolant is provided. 
     Optionally, the heating circuit comprises a heater arranged downstream of the condenser and downstream of the first return conduit. Thereby, a thermal management system is provided allowing the heater to heat the heating circuit without transferring the heat to the propulsion coolant circuit via the condenser. The heater may for example comprise an electrical heater or a fuel fired heater. As an alternative, or in addition, in embodiments where the vehicle comprises a hybrid electric propulsion system and the propulsion coolant circuit is arranged to cool electrical components of the propulsion system, the heater may comprise a heat exchanger arranged to transfer heat from a combustion engine coolant circuit to the heating circuit. 
     Optionally, the propulsion system is an electric propulsion system comprising power electronics and an electric machine, and wherein the propulsion coolant circuit is configured to cool at least one of the power electronics and the electric machine. Thereby, a flexible and more controllable thermal management system is provided allowing the heating circuit to operate at a higher temperature level than the temperature level of components of the electric propulsion system. Furthermore, a thermal management system is provided in which the condenser can be used for heating components of the electric propulsion system when needed by controlling the first valve to allow flow of coolant through the connecting conduit. 
     Optionally, the heat pump circuit comprises a second evaporator configured to cool the occupant compartment and a second valve controllable between a first state in which the second valve causes working media in the heat pump circuit to flow through the first evaporator, and a second state in which the second valve causes working media in the heat pump circuit to flow through the second evaporator. Thereby, a thermal management system is provided in which the heat pump circuit can be used to cool the occupant compartment. Thus, by controlling the first valve to allow flow of coolant through the connecting conduit and controlling the second valve to the second state, the heat collected by the second evaporator can be transferred to the condenser and transferred from the condenser to the surroundings via the propulsion coolant circuit. 
     Optionally, the system comprises a control arrangement configured to, in an occupant compartment cooling mode, control the first valve to allow flow of coolant through the connecting conduit and control the second valve to the second state. Thereby, a thermal management system is provided in which the heat pump circuit can be used to cool the occupant compartment in an efficient manner where the heat collected by the second evaporator can be transferred to the condenser and transferred from the condenser to the surroundings via the propulsion coolant circuit. 
     Optionally, the control arrangement is configured to, in an occupant compartment heating mode, control the first valve to hinder flow of coolant through the connecting conduit and control the second valve to the first state. Thereby, a thermal management system is provided in which the heat pump circuit can be used to heat the occupant compartment in an efficient manner where the heat collected by the first evaporator can be transferred to the heating circuit in an efficient manner via the condenser. 
     Optionally, the propulsion coolant circuit comprises a first radiator and a first coolant pump, and wherein the system comprises a control arrangement configured to, in a first heat pump operation mode, control the first valve to hinder flow of coolant through the connecting conduit and activate the first coolant pump so as to transfer heat collected from the surroundings by the first radiator to the first evaporator. Thereby, a thermal management system is provided in which heat from the surroundings can be utilized for heating the occupant compartment. As a result thereof, the occupant compartment can be heated in an energy efficient manner also in cases where substantially no excess heat is available in the propulsion system. As a further result thereof, the need for starting the propulsion system, or components thereof, for increasing the available heat in the propulsion system is circumvented. Accordingly, the thermal management system provides conditions for a more efficient utilization of energy in a propulsion system of a vehicle. 
     Optionally, the control arrangement is configured to operate the system in the first heat pump operation mode when the temperature level in the propulsion system is below a threshold level. Thereby, conditions are provided for a more efficient utilization of energy in a propulsion system of a vehicle. The threshold level may be set to a level in which it is determined that the heat available in the propulsion system is insufficient for heating the occupant compartment, and/or to a minimum temperature level required by components of the propulsion system. 
     Optionally, the propulsion coolant circuit comprises a coolant branch and a third valve configured to regulate the flow of coolant through the coolant branch, and wherein the first evaporator is arranged in the coolant branch. Thereby, a more flexible and more controllable thermal management system is provided in which flow of coolant through the first evaporator, and thus also the heat transfer to the first evaporator, can be regulated simply by controlling the third valve. 
     Optionally, the propulsion system is an electric propulsion system comprising a battery, and wherein the first evaporator is further configured to cool the battery. Thereby, a thermal management system is provided capable of utilizing heat generated by the battery for heating the occupant compartment. Moreover, conditions are provided for cooling the battery to a lower temperature level than other portions of the electric propulsion system such as the power electronics and/or the electric machine. 
     Optionally, the system comprises a battery coolant circuit configured to cool the battery, and wherein the battery coolant circuit comprises an inlet in the coolant branch downstream of the first evaporator and an outlet in the coolant branch upstream of the first evaporator. Thereby, a thermal management system is provided in which the battery can be cooled to a lower temperature level than other portions of the electric propulsion system such as the power electronics and/or the electric machine. 
     Optionally, the battery coolant circuit comprises a battery coolant branch, a battery radiator in the battery coolant branch, and a fourth valve configured to regulate the flow of coolant through the battery coolant branch. Thereby, a thermal management system is provided in which the battery can be cooled by the first evaporator as well as by the battery radiator. In this manner, an improved flexibility is provided, and the maximum cooling capacity of the battery is increased. Moreover, conditions are provided for a cooling of the battery in a manner being independent from the cooling of other components of the electric propulsion system, such as the power electronics and/or the electric machine. 
     Optionally, the battery coolant circuit comprises a battery coolant pump, and wherein the system comprises a control arrangement configured to, in a second heat pump operation mode, control the fourth valve to regulate flow of coolant through the battery coolant branch and activate the battery coolant pump so as to transfer heat collected from the surroundings by the battery radiator to the first evaporator. Thereby, a thermal management system is provided in which heat from the surroundings can be utilized for heating the occupant compartment. As a result thereof, the occupant compartment can be heated in an energy efficient manner also in cases where substantially no excess heat is available in the propulsion system. As a further result thereof, the need for starting the propulsion system, or components thereof, for increasing the available heat in the propulsion system is circumvented. Accordingly, the thermal management system provides conditions for a more efficient utilization of energy in a propulsion system of a vehicle. 
     Optionally, the control arrangement is configured to operate the system in the second heat pump operation mode when the temperature level in the propulsion system is below a threshold level. Thereby, conditions are provided for a more efficient utilization of energy in a propulsion system of a vehicle. 
     Optionally, the heating circuit comprises a heat exchanger configured to heat the occupant compartment, and wherein the first return conduit is configured to return coolant to the propulsion coolant circuit from the heating circuit at a position upstream of the heat exchanger. Thereby, coolant can be returned to the propulsion coolant circuit without passing the heat exchanger of the heating circuit. 
     Optionally, the propulsion coolant circuit comprises a second return conduit configured to return coolant to the propulsion coolant circuit from the heating circuit at a position downstream of the heat exchanger. Thereby, conditions are provided for selecting if the coolant ducted from the propulsion coolant circuit shall pass the heat exchanger or not simply by controlling the flow through the first and second return conduits. 
     Optionally, the system comprises a flow control arrangement controllable between a first state in which the flow control arrangement directs coolant through the first return conduit and a second state in which the flow control arrangement directs coolant through the second return conduit. Thereby, a system is provided capable of selecting if the coolant ducted from the propulsion coolant circuit shall pass the heat exchanger or not simply by controlling the flow control arrangement between the first and second states. 
     Optionally, the heating circuit comprises a heat exchanger and a fan configured to generate an airflow through the heat exchanger towards the occupant compartment, and wherein the system comprises a valve arrangement controllable to a state in which the valve arrangement directs at least part of the airflow to the surroundings. In this manner, a thermal management system is provided with improved maximum cooling capacity of components of the propulsion system. This because heat collected from the propulsion coolant circuit can be transferred from the condenser to the surroundings via the heating circuit. That is, due to the valve arrangement, more heat can be dissipated from the heating circuit, and thus also from the propulsion coolant circuit, than what is needed given a current heating demand of the occupant compartment. 
     Accordingly, a thermal management system is provided improving the maximum cooling capacity of components of the propulsion system in a manner circumventing the need for using larger radiator, larger pumps, hoses, and the like, which would add cost, weight, and complexity to the thermal management system. Thus, the maximum cooling capacity of components of the propulsion system is improved in a cost and energy efficient manner. 
     Optionally, the heating circuit comprises a heating circuit pump configured to pump coolant through the heating circuit, and wherein the heating circuit pump is arranged between the connecting conduit and the first return conduit. In this manner, the heating circuit pump will pump coolant from the connecting conduit and trough the condenser when the first valve is controlled to allow flow of coolant through the connecting conduit. 
     According to a second aspect of the invention, the object is achieved by a powertrain for a vehicle, wherein the powertrain comprises a propulsion system configured to provide motive power to the vehicle, and a thermal management system according to some embodiments of the present disclosure. 
     Since the powertrain comprises a thermal management system according to some embodiments of the present disclosure, a more flexible and thermally controllable powertrain is provided allowing the heating circuit of the thermal management system to operate at a higher temperature level than the temperature level of the propulsion coolant circuit. In this manner, the heat pump circuit of the thermal management system can transfer heat from the propulsion coolant circuit to the heating circuit in a more efficient manner for example during wintertime when the ambient temperature is low, and the heating demand of the occupant compartment is high. 
     Moreover, a powertrain is provided in which the condenser of the thermal management can be cooled by the propulsion coolant circuit by controlling the first valve to allow flow of coolant through the connecting conduit, for example during summertime when the ambient temperature is higher, and the heating demand of the occupant compartment is lower. Furthermore, a powertrain is provided in which the condenser of the thermal management can be used for heating components of the propulsion system when needed by controlling the first valve to allow flow of coolant through the connecting conduit. 
     Thus, due to these features, heat can be transferred to and from the propulsion system of the powertrain in a more efficient manner, meaning that conditions are provided for a more efficient utilization of energy in a vehicle comprising the powertrain. Moreover, a powertrain is provided capable of improving the heating performance of the occupant compartment of the vehicle. 
     Accordingly, a powertrain is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved. 
     According to a third aspect of the invention, the object is achieved by a vehicle comprising an occupant compartment and a powertrain according to some embodiments of the present disclosure. 
     Since the vehicle comprises a powertrain according to some embodiments of the present disclosure, a vehicle is provided comprising a more flexible and more controllable thermal management system in which the heating circuit is allowed to operate at a higher temperature level than the temperature level of the propulsion coolant circuit. In this manner, the heat pump circuit of the thermal management system can transfer heat from the propulsion coolant circuit to the heating circuit in a more efficient manner for example during wintertime when the ambient temperature is low, and the heating demand of the occupant compartment of the vehicle is high. 
     Moreover, a vehicle is provided in which the condenser of the thermal management can be cooled by the propulsion coolant circuit by controlling the first valve to allow flow of coolant through the connecting conduit, for example during summertime when the ambient temperature is higher, and the heating demand of the occupant compartment is lower. Furthermore, a vehicle is provided in which the condenser of the thermal management can be used for heating components of the propulsion system when needed by controlling the first valve to allow flow of coolant through the connecting conduit. 
     Thus, due to these features, heat can be transferred to and from the propulsion system of the vehicle in a more efficient manner, meaning that conditions are provided for a more efficient utilization of energy in the vehicle. Moreover, a vehicle is provided having conditions for an improved heating performance of the occupant compartment. 
     Accordingly, a vehicle is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved. 
     Further features of, and advantages with, the present invention will become apparent when studying 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 be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which: 
         FIG. 1  schematically illustrates a thermal management system, according to some embodiments, 
         FIG. 2  schematically illustrates a thermal management system, according to some further embodiments, 
         FIG. 3  schematically illustrates a thermal management system, according to some further embodiments, and 
         FIG. 4  illustrates a vehicle according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity. 
       FIG. 1  schematically illustrates a thermal management system  1  according to some embodiments. The thermal management system  1  is configured to control transfer of heat in a vehicle, wherein the vehicle comprises an occupant compartment  5  and a propulsion system  7 ,  8 ,  9  configured to provide motive power to the vehicle. The occupant compartment  5  is configured to accommodate one or more occupants. The thermal management system  1  is in some places herein referred to as “the system  1 ” for the reason of brevity and clarity. According to the illustrated embodiments, propulsion system  7 ,  8 ,  9  is an electric propulsion system  7 ,  8 ,  9  comprising power electronics  7 , an electric machine  8 , and a battery  9 . The electric machine  8  is configured to provide motive power to the vehicle using electric energy stored in the battery  9  by an amount controlled by the power electronics  7 . 
     According to further embodiments of the present disclosure, the propulsion system  7 ,  8 ,  9 , as referred to herein, may comprise a combustion engine such as for example a compression ignition engine, such as a diesel engine, or an Otto engine with a spark-ignition device, wherein the Otto engine may be configured to run on gas, petrol, alcohol, similar fuels, or combinations thereof. According to still further embodiments of the present disclosure, the propulsion system  7 ,  8 ,  9 , as referred to herein, may comprise a combustion engine in addition to power electronics  7 , an electric machine  8  and a battery  9 . According to such embodiments, the propulsion system  7 ,  8 ,  9  may be referred to as a hybrid electric propulsion system  7 ,  8 ,  9 . The combustion engine of such a hybrid electric propulsion system  7 ,  8 ,  9  may for example comprise a compression ignition engine, such as a diesel engine, or an Otto engine with a spark-ignition device, wherein the Otto engine may be configured to run on gas, petrol, alcohol, similar fuels, or combinations thereof. 
     The thermal management system  1  comprises a propulsion coolant circuit  11  configured to cool at least a portion  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9 . The propulsion coolant circuit  11  comprises a first radiator  49 , coolant channels in the components  7 ,  8 ,  9  to be cooled, and a first coolant pump  14  arranged to pump coolant through the propulsion coolant circuit  11 . The propulsion coolant circuit  11  further comprises a radiator valve  47  arranged to direct flow to the first radiator  49  and/or to a bypass line bypassing the first radiator  49 . The propulsion coolant circuit  11  further comprises an expansion tank  53  arranged upstream of the first coolant pump  14 . The thermal management system  1  further comprises a heating circuit  13  configured to heat the occupant compartment  5 . According to the illustrated embodiments, the heating circuit  13  comprises a heat exchanger  31  and a heating circuit pump  34  configured to pump coolant through the heating circuit  13 . Moreover, according to the illustrated embodiments, the system  1  comprises a fan  33  configured to generate an airflow through the heat exchanger  31  towards the occupant compartment  5 . The heat exchanger  31  is thus configured to heat the occupant compartment  5 . 
     The system  1  further comprises a heat pump circuit  15  comprising a first evaporator  21  in the propulsion coolant circuit  11  and a condenser  23  in the heating circuit  13 . Furthermore, the heat pump circuit  15  comprises a first expansion valve  28  arranged upstream of the first evaporator  21  and a compressor  24  arranged to pump working media, such as a refrigerant, through the heat pump circuit  15 . 
     The propulsion coolant circuit  11  comprises a connecting conduit  11 ′ connecting the propulsion coolant circuit  11  to the heating circuit  13  at a position upstream of the condenser  23 . An outlet of the connecting conduit  11 ′ is thus positioned upstream of the condenser  23  such that coolant flowing through the connecting conduit  11 ′ flows into the heating circuit  13  at a position upstream of the condenser  23 . Moreover, the propulsion coolant circuit  11  comprises a first return conduit  11   r  configured to return coolant to the propulsion coolant circuit  11  from the heating circuit  13  at a position downstream of the condenser  23 . An inlet of the first return conduit  11   r  is thus positioned downstream of the condenser  23  such that coolant is flowing from the heating circuit  13  at a position downstream of the condenser  23  into the first return conduit  11   r.    
     Moreover, the system  1  comprises a first valve  25 . The first valve  25  is configured to control flow of coolant through the connecting conduit  11 ′. That is, the first valve  25  is controllable between a first state, in which the first valve  25  allows flow of coolant through the connecting conduit  11 ′, and a second state, in which the first valve  25  hinders flow of coolant through the connecting conduit  11 ′. In more detail, according to the embodiments illustrated in  FIG. 1 , the first valve  25  comprises one outlet and a first and a second inlet. The outlet is connected to the heating circuit pump  34  of the heating circuit  13 , the first inlet is connected to the connecting conduit  11 ′ and the second inlet is connected to heat exchanger  31  of the heating circuit  13 . In the first state, the first valve opens the first inlet, and in the second state, the first valve  25  closes the first inlet. As indicated in  FIG. 1 , the propulsion coolant circuit  11  comprises a bypass line  11 ″ bypassing the connecting conduit  11 ′. The bypass line  11 ″ forms a continuation of the propulsion coolant circuit  11  and is connected to the first coolant pump  14  of the propulsion coolant circuit  11 . The bypass line  11 ″ may also be referred to as a portion  11 ″ of the propulsion coolant circuit  11  upstream of the first coolant pump  14  of the propulsion coolant circuit  11 . The coolant is directed to the bypass line  11 ″ instead of flowing through the connecting conduit  11 ′ when the first valve  25  is in the second state. 
     In this manner, as is further explained herein, the heat pump circuit  15  can be fluidly isolated from the propulsion coolant circuit  11  simply by controlling the first valve  25  to the second state. Thereby, the heat pump circuit  15  can be operated at a higher temperature level than the propulsion coolant circuit  11 , which provides several advantages, as is further explained herein. 
     According to the embodiments illustrated in  FIG. 1 , the heating circuit pump  34  is arranged between the connecting conduit  11 ′ and the first return conduit  11   r . Thus, according to the embodiments illustrated in  FIG. 1 , the heating circuit pump  34  will pump coolant from the connecting conduit  11 ′, through the condenser  23  when the first valve  25  is in the first state. In this manner, a stable pressure distribution is obtained in the respective circuit  11 ,  13 . The heating circuit  13  comprises a heater  27  arranged downstream of the condenser  23  and downstream of the first return conduit  11   r . The heater  27  may for example comprise an electrical heater or a fuel fired heater. As an alternative, or in addition, in embodiments where the propulsion system  7 ,  8 ,  9  is a hybrid electric propulsion system and the propulsion coolant circuit  11  is arranged to cool electrical components  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9 , the heater  27  may comprise a heat exchanger arranged to transfer heat from a combustion engine coolant circuit to the heating circuit  13 . 
     As understood from the above, coolant of the propulsion coolant circuit  11  and coolant of the heating circuit  13  will be at least partially mixed in coolant channels  23 ′ of the condenser  23  when the first valve  25  is in the first state. 
     According to the illustrated embodiments, the first return conduit  11   r  is configured to return coolant to the propulsion coolant circuit  11  from the heating circuit  13  at a position upstream of the heat exchanger  31 . Moreover, according to the embodiments illustrated in  FIG. 1 , the propulsion coolant circuit  11  comprises a second return conduit  11   r . The second return conduit  11   r  is configured to return coolant to the propulsion coolant circuit  11  from the heating circuit  13  at a position downstream of the heat exchanger  31 . An inlet of the second return conduit  11   r  is thus positioned downstream of the heat exchanger  31 . 
     Furthermore, according to the embodiments illustrated in  FIG. 1 , the system  1  comprises a flow control arrangement  38 ,  39 . According to the illustrated embodiments, the flow control arrangement  38 ,  39  comprises a valve  38  in the first return conduit  11   r  and a flow restrictor  39  in the second return conduit  11   r . According to further embodiments, the second return conduit  11   r  may comprise a valve and the first return conduit  11   r  may comprise a flow restrictor. According to the illustrated embodiments, the flow restrictor  39  comprises an anti-mixing loop. The flow control arrangement  38 ,  39  is controllable between a first state in which the flow control arrangement  38 ,  39  directs coolant through the first return conduit  11   r  and a second state in which the flow control arrangement  38 ,  39  directs coolant through the second return conduit  11   r.    
     In the first state, the valve  38  in the first return conduit  11   r  is opened to allow flow of coolant through the first return conduit  11   r . When the flow control arrangement  38 ,  39  is in the first state, i.e. when the valve  38  in the first return conduit  11   r  is opened, the flow restrictor  39  hinders flow of coolant through the second return conduit  11   r ′. In the second state, the valve  38  in the first return conduit  11   r  is closed to hinder flow of coolant through the first return conduit  11   r . When the flow control arrangement  38 ,  39  is in the second state, i.e. when the valve  38  in the first return conduit  11   r  is closed, the flow restrictor  39  allows flow of coolant through the second return conduit  11   r ′. In this manner, the coolant can be returned to the propulsion coolant circuit  11  in a manner bypassing the heat exchanger  31  of the heating circuit  13  or in a manner where the returned coolant has flown through the heat exchanger  31  of the heating circuit  13 , simply by controlling the flow control arrangement  38 ,  39  between the first and second states. The flow control arrangement  38 ,  39  can thus be utilized to increase the flow rate of coolant through the condenser  23  when there is a low heating need of the occupant compartment  5 , such as during summertime. That is, by controlling the flow control arrangement  38 ,  39  to the first state, i.e. by opening the valve  38 , a lower pressure drop is provided which can increase the flow rate of coolant through the condenser  23 . 
     According to the illustrated embodiments, the heat pump circuit  15  comprises a second evaporator  22  configured to cool the occupant compartment  5 . Moreover, the heat pump circuit  15  comprises a second valve  29  controllable between a first state in which the second valve  29  causes working media in the heat pump circuit  15  to flow through the first evaporator  21 , and a second state in which the second valve  29  causes working media in the heat pump circuit  15  to flow through the second evaporator  22 . According to the illustrated embodiments, the second valve  29  is a three-way valve comprising an inlet connected to the condenser  23 , a first outlet connected to the first evaporator  21  and a second outlet connected to the second evaporator  22 . In the first state, the second valve  29  opens a connection to the first evaporator  21  and closes the connection to the second evaporator  22 . In the second state, the second valve  29  opens a connection to the second evaporator  22  and closes the connection to the first evaporator  21 . According to some embodiments, the second valve  29  may be controllable to a third state in which the second valve  29  opens the connection to the first evaporator  21  as well as opens the connection to the second evaporator  22 , as is further explained herein. 
     The heat pump circuit  15  comprises a second expansion valve  28 ′ arranged upstream of the second evaporator  22 . In this manner, as is further explained herein, the heat pump circuit  15  can be utilized to cool the occupant compartment  5 , i.e. used as an air conditioning unit for cooling the occupant compartment  5 . According to the illustrated embodiments, the system  1  comprises a fan  33  configured to generate an airflow through the second evaporator  22  towards the occupant compartment  5 . 
     According to the illustrated embodiments, the propulsion coolant circuit  11  comprises a coolant branch  11 ′″ and a third valve  26  configured to regulate the flow of coolant through the coolant branch  11 ′″, wherein the first evaporator  21  is arranged in the coolant branch  11 ′″. Thereby, a more flexible and more controllable thermal management system  1  is provided in which flow of coolant through the first evaporator  21 , and thus also the heat transfer to the first evaporator  21 , can be regulated simply by controlling the third valve  26 . 
     Moreover, according to the illustrated embodiments, the first evaporator  21  is further configured to cool the battery  9 . Thereby, a thermal management system  1  is provided capable of utilizing heat generated by the battery  9  for heating the occupant compartment  5 . Moreover, conditions are provided for cooling the battery  9  to a lower temperature level than other portions of the electric propulsion system  7 ,  8 ,  9  such as the power electronics  7  and/or the electric machine  8 . As an alternative, or in addition, the first evaporator  21  may be further configured to cool one or more types of components, such as one or more capacitors, or the like. The system  1  comprises a battery coolant circuit  41 ,  41 ′ configured to cool the battery  9 . The battery coolant circuit  41 ,  41 ′ comprises an inlet  45  in the coolant branch  11 ′″ downstream of the first evaporator  21  and an outlet  45 ′ in the coolant branch  11 ′″ upstream of the first evaporator  21 . The battery coolant circuit  41 ,  41 ′ comprises a battery coolant branch  41 ′, a battery coolant pump  46  arranged to pump coolant through the battery coolant circuit  41 ,  41 ′, a battery radiator  51  in the battery coolant branch  41 ′, and a fourth valve  43  configured to regulate the flow of coolant through the battery coolant branch  41 ′. 
     Due to these features, a thermal management system  1  is provided in which the battery  9  can be cooled by the first evaporator  21  as well as by the battery radiator  51 . In this manner, an improved controllability is provided and the maximum cooling capacity of the battery  9  is increased. Moreover, conditions are provided for a cooling of the battery  9  in a manner being independent from the cooling of other components of the electric propulsion system  7 ,  8 ,  9  such as the power electronics  7  and/or the electric machine  8 . 
     According to the illustrated embodiments, the system  1  comprises a valve arrangement  35  controllable to a state in which the valve arrangement  35  directs at least part of the airflow generated by the fan  33  to the surroundings  37 . That is, in this state, the valve arrangement  35  directs at least part of the airflow generated by the fan  33  to the surroundings  37  instead of the occupant compartment  37 . In this manner, a thermal management system  1  is provided with improved maximum cooling capacity of components  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9 . This because heat collected from the propulsion coolant circuit  11  can be transferred from the condenser  23  to the surroundings  37  via the heating circuit  13 . That is, due to the valve arrangement  35 , more heat can be dissipated from the heating circuit  13 , and thus also from the propulsion coolant circuit  11 , than what is needed given a current heating demand of the occupant compartment  5 . 
     According to the illustrated embodiments, the thermal management system  1  comprises a control arrangement  50  connected to components  14 ,  24 ,  25 ,  26 ,  29 ,  33 ,  34 ,  35 ,  38 ,  43 ,  46 ,  47  of the thermal management system  1  and being configured to control the components  14 ,  24 ,  25 ,  26 ,  29 ,  33 ,  34 ,  35 ,  38 ,  43 ,  46 ,  47  of the thermal management system  1 . 
     The control arrangement  50  is configured to, in an occupant compartment heating mode, control the first valve  25  to the second state and control the second valve  29  to the first state. Moreover, in the occupant compartment heating mode, the control arrangement  50  may control the third valve  26  to direct at least part of the flow to the coolant branch  11 ′″, and activate the first coolant pump  14 , the compressor  24 , the heating circuit pump  34 , and/or the fan  33 . In this manner, heat generated by the power electronics  7  and/or the electric machine  8  can be transferred to the occupant compartment  5  via the heating circuit  13  in an efficient manner and in a manner allowing the heating circuit  13  to have a higher temperature level than the propulsion coolant circuit  11 . In the occupant compartment heating mode, the control arrangement  50  may control the radiator valve  47  to bypass the first radiator  49  or to direct coolant to the first radiator  49  depending on a cooling demand of the power electronics  7  and/or the electric machine  8 . 
     Furthermore, in a second occupant compartment heating mode, when excess heat is available in the battery  9 , the control arrangement  50  may activate the battery coolant pump  46 . In this manner, heat from the battery  9  can be transferred to the first evaporator  21 . Moreover, in the second occupant compartment heating mode, the control arrangement  50  may control the first valve  25  to the second state, control the second valve  29  to the first state, and activate the first coolant pump  14 , the compressor  24 , the heating circuit pump  34 , and/or the fan  33 . In the second occupant compartment heating mode, the control arrangement  50  may control the third valve  26  to a closed state, in which no coolant is directed to the coolant branch  11 ′″, or a partially open state in which some coolant is directed to the coolant branch  11 ′″, based on available heat generated by the power electronics  7  and/or the electric machine  8 . 
     The control arrangement  50  is configured to, in an occupant compartment cooling mode, control the first valve  25  to the first state and control the second valve  29  to the second state. Moreover, in the occupant compartment cooling mode, the control arrangement  50  may activate the first coolant pump  14 , the compressor  24 , and/or the fan  33 . In this manner, the second evaporator  22  can cool the occupant compartment  5  in an efficient manner and the heat collected by the second evaporator  22  can be dissipated to the surroundings  37  via the first radiator  49 . In the occupant compartment cooling mode, the control arrangement  50  may control the radiator valve  47  to direct coolant to the first radiator  49 . As an alternative, if there is a heating demand of one or more of the components  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9 , the control arrangement  50  may control the radiator valve  47  to bypass the first radiator  49  so as to provide heating of one or more of the components  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9  using heat collected by the second evaporator  22 . 
     The control arrangement  50  may be configured to, in a second occupant compartment cooling mode, control the second valve  29  to the third state. In this manner, the second valve  29  opens a connection from the condenser  23  to the first evaporator  21  as well as a connection from the condenser  23  to the second evaporator  22 . As a result thereof, the first evaporator  21  can be utilized to cool the battery  9  and the second evaporator  22  can be utilized to cool the occupant compartment  5 . In the third occupant compartment cooling mode, the control arrangement  50  may activate the battery coolant pump  46 , control the first valve  25  to the first state, and activate the first coolant pump  14 , the compressor  24 , and/or the fan  33 . In the second occupant compartment cooling mode, the control arrangement  50  may control the third valve  26  to a closed state, in which no coolant is directed to the coolant branch  11 ′″, or a partially open state in which some coolant is directed to the coolant branch  11 ′″. 
     According to some embodiments, the control arrangement  50  is configured to, in a first heat pump operation mode, control the first valve  25  to the second state, control the control the radiator valve  47  to direct coolant to the first radiator  49  and activate the first coolant pump  14  so as to transfer heat collected from the surroundings  37  by the first radiator  49  to the first evaporator  21 . Moreover, in the first heat pump operation mode, the control arrangement  50  may be configured to control the second valve  29  to the first state, activate the compressor  24 , the heating circuit pump  34 , and/or the fan  33 . Furthermore, in the first heat pump operation mode, the control arrangement  50  may control the third valve  26  to direct at least part of the flow to the coolant branch  11 ′″. 
     In this manner, a thermal management system  1  is provided in which heat from the surroundings  37 , collected by the first radiator  49 , can be utilized for heating the occupant compartment  5 . As a result thereof, the occupant compartment  5  can be heated in an energy efficient manner also in cases where substantially no excess heat is available in the propulsion system  7 ,  8 ,  9 . As a further result thereof, the need for starting the propulsion system  7 ,  8 ,  9 , or components  7 ,  8 ,  9  thereof, for increasing the available heat in the propulsion system  7 ,  8 ,  9 , is circumvented. Accordingly, the thermal management system  1  provides conditions for a more efficient utilization of energy in a propulsion system  7 ,  8 ,  9  of a vehicle. The control arrangement  50  may be configured to operate the system  1  in the first heat pump operation mode when the temperature level in the propulsion system  7 ,  8 ,  9  is below a threshold level, and/or when the temperature level in the propulsion system  7 ,  8 ,  9  is predicted to become below a threshold level. 
     Furthermore, according to some embodiments, the control arrangement  50  may be configured to, in a second heat pump operation mode, control the fourth valve  43  to regulate flow of coolant through the battery coolant branch  41 ′ and activate the battery coolant pump  46  so as to transfer heat collected from the surroundings  37  by the battery radiator  51  to the first evaporator  21 . Moreover, in the second heat pump operation mode, the control arrangement  50  may be configured to control the first valve  25  to the second state, control the second valve  29  to the first state, activate the compressor  24 , the heating circuit pump  34 , and/or the fan  33 . In this manner, a thermal management system  1  is provided in which heat from the surroundings  37 , collected by the battery radiator  51 , can be utilized for heating the occupant compartment  5 . Moreover, in the second heat pump operation mode, heat from the surroundings  37  can be utilized for heating the occupant compartment  5  in a manner less dependent on the temperature of other components  7 ,  8  of the propulsion system  7 ,  8 ,  9 . The control arrangement  50  may be configured to operate the system  1  in the second heat pump operation mode when the temperature level in the propulsion system  7 ,  8 ,  9  is below a threshold level, and/or when the temperature level in the propulsion system  7 ,  8 ,  9  is predicted to become below a threshold level. 
       FIG. 2  schematically illustrates a thermal management system  1 , according to some further embodiments. The thermal management system  1  according to the embodiments illustrated in  FIG. 2  comprises the same features, functions, and advantages as the thermal management system  1  described with reference to  FIG. 1 , with some differences, explained below. 
     According to the embodiments illustrated in  FIG. 2 , the first valve  25  comprises two outlets and one inlet, wherein the inlet is connected to the heat exchanger  31  of the heating circuit  13 , a first outlet is connected to the heating circuit pump  34  of the heating circuit  13  and a second outlet is connected to the first return conduit  11   r . The first return conduit  11   r  is configured to return coolant to the propulsion coolant circuit  11  from the heating circuit  13  at a position downstream of the condenser  23 . An inlet of the first return conduit  11   r  is thus positioned downstream of the condenser  23  such that coolant is flowing from the heating circuit  13  at a position downstream of the condenser  23  into the first return conduit  11   r.    
     The first return conduit  11   r  extends between the first valve  25  and a portion  11 ″ of the propulsion coolant circuit  11  upstream of the first coolant pump  14  of the propulsion coolant circuit  11 . Moreover, according to the embodiments illustrated in  FIG. 2 , the connecting conduit  11 ′ is connected to the heating circuit  13  at a position between the first outlet of the first valve  25  and the heating circuit pump  34 . Furthermore, the connecting conduit  11 ′ comprises a flow restrictor  42  in the form of an anti-mixing loop. According to further embodiments, the connecting conduit  11 ′ may comprise another type of flow restrictor  42 , such as a one way valve, or the like. The connecting conduit  11 ′ is connecting the propulsion coolant circuit  11  to the heating circuit  13  at a position upstream of the condenser  23 . An outlet of the connecting conduit  11 ′ is thus positioned upstream of the condenser  23  such that coolant flowing through the connecting conduit  11 ′ flows into the heating circuit  13  at a position upstream of the condenser  23 . 
     The first valve  25  is configured to control flow of coolant through the connecting conduit  11 ′, i.e. is controllable to hinder or allow flow of coolant through the connecting conduit  11 ′. In more detail, the first valve  25  is controllable between a first state and a second state. In the first state, the first valve  25  closes the first outlet connected to heating circuit pump  34  and opens the second outlet connected to the return conduit  11   r . In this manner, coolant is allowed to flow through the connecting conduit  11 ′ to the heating circuit pump  34  when the first valve  25  is in the first state and the heating circuit pump  34  is pumping coolant. In the second state, the first valve  25  closes the second outlet connected to the first return conduit  11   r  and opens the first outlet connected to heating circuit pump  34 . In this manner, coolant flows from the first outlet of the first valve  25  to the heating circuit pump  34  when the first valve  25  is in the second state and the heating circuit pump  34  is pumping coolant. As a further result, coolant is hindered from flowing through the connecting conduit  11 ′ when the valve is in the second state. This because the first valve  25  closes the second outlet connected to the first return conduit  11   r  when in the second state. Thereby, no flow of coolant is obtained through the connecting conduit  11 ′ and coolant of the propulsion coolant circuit  11  will instead flow through the portion  11 ″ of the propulsion coolant circuit  11  connected to the first coolant pump  14  when the first valve  25  is in the second state. The portion  11 ″ of the propulsion coolant circuit  11  connected to the first coolant pump  14  may also be referred to as a bypass line  11 ″ since it bypasses the connecting conduit  11 ′. 
     An advantage with the solution according to the embodiments illustrated in  FIG. 2  is that the heating circuit pump  34  can pump coolant with a low pressure drop through the connecting conduit  11 ′ because of the valve-less connection between the heating circuit pump  34  and the expansion tank  53  of the propulsion coolant circuit  11 . Thereby the pump inlet pressure at the heating circuit pump  34  is kept high giving increased margin for e.g. pump cavitation in the heating circuit pump  34 . 
     As indicated above, according to the embodiments illustrated in  FIG. 2 , the first valve  25  is arranged downstream of the heat exchanger  31  of the heating circuit  13 . Accordingly, the first return conduit  11   r  is configured to return coolant to the propulsion coolant circuit  11  from the heating circuit  13  at a position downstream of the heat exchanger  31 . Consequently, coolant returned from the heating circuit  13  via the first return conduit  11   r  has passed the heat exchanger  31  of the heating circuit  13 . However, according to the embodiments illustrated in  FIG. 2 , the propulsion coolant circuit  11  further comprises a second return conduit  11   r . The second return conduit  11   r ′ is configured to return coolant to the propulsion coolant circuit  11  from the heating circuit  13  at a position upstream of the heat exchanger  31 . An inlet of the second return conduit  11   r ′ is thus positioned upstream of the heat exchanger  31 . The system  1  further comprises a valve  38  configured to control flow of coolant through the second return conduit  11   r . In more detail, the valve  38  is controllable between a closed state in which the valve  38  hinders flow of coolant through the second return conduit  11   r ′ and an open state, in which the in which the valve  38  allows flow of coolant through the second return conduit  11   r . Thus, by controlling the valve  38  to the open state, coolant can be returned to the propulsion coolant circuit  11  from the heating circuit  13  at a position upstream of the heat exchanger  31 . The valve  38  can thus be utilized to increase the flow rate of coolant through the condenser  23  when there is a low heating need of the occupant compartment  5 , such as during summertime. That is, by controlling the valve  38  to the open state, a lower pressure drop is provided which can increase the flow rate of coolant through the condenser  23 . 
     As seen in  FIG. 2 , an inlet of the connecting conduit  11 ′ is arranged upstream of outlets of the respective first and second return conduits  11   r ,  11   r ′ at the propulsion coolant circuit  11 . In this manner, it can be ensured that coolant having a low temperature is flowing from the propulsion coolant circuit  11  to the heating circuit  13  via the first connecting conduit  11 ′. 
       FIG. 3  schematically illustrates a thermal management system  1 , according to some further embodiments. The thermal management system  1  according to the embodiments illustrated in  FIG. 3  may comprise the same features, functions, and advantages as the thermal management system  1  described with reference to  FIG. 1  or  FIG. 2 , with some exceptions, explained below. 
     According to the embodiments illustrated in  FIG. 3 , the propulsion coolant circuit  11  comprises a bypass line  11 ″ bypassing the connecting conduit  11 ′. The bypass line  11 ″ forms a continuation of the propulsion coolant circuit  11 . According to the embodiments illustrated in  FIG. 1 , the first valve  25  is controllable between a first state, in which the first valve  25  directs coolant through the connecting conduit  11 ′, and a second state, in which the first valve  25  directs coolant through the bypass line  11 ″. In more detail, according to the embodiments illustrated in  FIG. 3 , the first valve  25  comprises one inlet and a first and a second outlet. The inlet is connected to the first coolant pump  14  of the propulsion coolant circuit  11 , the first outlet is connected to the connecting conduit  11 ′ and the second outlet is connected to the bypass line  11 ′. In the first state the first valve  25  opens the first outlet and closes the second outlet. In the second state the first valve  25  opens the second outlet and closes the first outlet. 
     Moreover, according to the embodiments illustrated in  FIG. 3 , the heating circuit pump  34  of the heating circuit  13  is not positioned between the connecting conduit  11 ′ and the first return conduit  11   r . Instead, the heating circuit pump  34  of the heating circuit  13  is position downstream of the first return conduit  11   r  and upstream of the connecting conduit  11 ′. Therefore, according to the embodiments illustrated in  FIG. 3 , the first coolant pump  14  of the propulsion coolant circuit  11  will pump coolant through the connecting conduit  11 ′, the condenser  23  and the first return conduit  11   r  when the first valve  25  is in the first state. Moreover, the heating circuit pump  34  of the heating circuit  13  is configured to pump coolant of the heating circuit  13  through the condenser  23 . Therefore, according to these embodiments, a higher flow rate of coolant through the condenser  23  can be obtained. 
     According to the embodiments illustrated in  FIG. 3 , the system  1  comprises only one return conduit  11   r . Therefore, according to these embodiments, the first return conduit  11   r  may simply be referred to as “the return conduit  11   r ”. However, in the following, the wording “the first return conduit  11   r ” is used. 
     Since the heating circuit pump  34  of the heating circuit  13  is positioned outside of the circuit formed by the connecting conduit  11 ′, the coolant channels  23 ′ of the condenser  23 , and the first return conduit  11   r , the connecting conduit  11 ′, the coolant channels  23 ′ of the condenser  23  and the first return conduit  11   r  may according to these embodiments be referred to as a coolant branch  11 ′,  23 ′,  11   r  of the propulsion coolant circuit  11 . Such a coolant branch  11 ′,  23 ′,  11   r  and the heating circuit  13  shares the same coolant channels  23 ′ in the condenser  23 . Thereby, a simple and efficient system  1  is provided requiring less complex and costly components. As understood from the above, coolant of the propulsion coolant circuit  11  and coolant of the heating circuit  13  will be at least partially mixed when the first valve  25  is in the first state. 
     As can be seen in  FIG. 3 , the heating circuit  13  comprises a one way valve  36  arranged between the first valve  25  and the heat exchanger  31  of the heating circuit  13 . The one way valve  36  is arranged to hinder flow of coolant from the first valve  25  towards the heat exchanger  31  of the heating circuit  13  when the first valve  25  is in the first state. 
     The control arrangement  50  as described herein may be configured to control the components  14 ,  24 ,  25 ,  26 ,  29 ,  33 ,  34 ,  35 ,  38 ,  43 ,  46 ,  47  of the system  1 , and to operate the system  1  in the different operation modes, based on temperature levels of components  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9 , heating/cooling demands of the components  7 ,  8 ,  9  of the propulsion system  7 ,  8 ,  9 , and/or a heating/cooling demand of the occupant compartment  5 . 
     One skilled in the art will appreciate that the operation modes of the system  1  may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in the control arrangement  50 , ensures that the control arrangement  50  carries out the desired control, such as the operation modes of the system  1  described herein. The computer program is usually part of a computer program product which comprises a suitable digital storage medium on which the computer program is stored. 
     The control arrangement  50  may comprise a calculation unit which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. 
     The control arrangement  50  may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated 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 or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments. 
     The control arrangement  50  is connected to components of the system  1  for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement  50 . These signals may then be supplied to the calculation unit. One or more output signal sending devices may be arranged to convert calculation results from the calculation unit to output signals for conveying to other parts of the vehicle&#39;s control system and/or the component or components for which the signals are intended. Each of the connections to the respective components of the system  1  for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection. 
     In the embodiments illustrated, the system  1  comprises a control arrangement  50  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 system consisting of one or more communication buses for connecting a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. Such a control system may comprise a large number of control units and taking care of a specific function may be shared between two or more of them. Vehicles of the type here concerned are therefore often provided with significantly more control arrangements than depicted in  FIG. 1 - FIG. 3 , as one skilled in the art will surely appreciate. 
     The computer program product may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the operation modes of the system  1  according to some embodiments when being loaded into one or more calculation units of the control arrangement  50 . The data carrier may be, e.g. a CD ROM disc, or a ROM (read-only memory), a PROM (programmable read-only memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. The computer program product may furthermore be provided as computer program code on a server and may be downloaded to the control arrangement  50  remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems. 
       FIG. 4  illustrates a vehicle  3  according to some embodiments. The vehicle  3  comprises an occupant compartment  5  configured to accommodate one or more occupants. Moreover, the vehicle  3  comprises a powertrain  60  comprising a propulsion system  7 ,  8 ,  9  configured to provide motive power to the vehicle  3 , via wheels  62  of the vehicle  3 . Furthermore, the powertrain  60  may comprise a thermal management system  1  according to any one of the embodiments illustrated in  FIG. 1 - FIG. 3 . Moreover, the propulsion system  7 ,  8 ,  9  may be a propulsion system  7 ,  8 ,  9  according to any one of the embodiments illustrated in  FIG. 1 - FIG. 3 , i.e. an electric propulsion system  7 ,  8 ,  9 . As an alternative, or in addition, the propulsion system of the powertrain  60  may comprise an internal combustion engine such as for example a compression ignition engine, such as a diesel engine, or an Otto engine with a spark-ignition device, wherein the Otto engine may be configured to run on gas, petrol, alcohol, similar fuels, or combinations thereof. 
     According to the illustrated embodiments, the vehicle  3  is a truck. However, according to further embodiments, the vehicle  3 , as referred to herein, may be another type of manned or unmanned vehicle for land or water based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a ship, a boat, or the like. 
     It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims. 
     The battery  9 , as referred to herein, may comprise a set of batteries each comprising a number of battery cells. The electric machine  8 , as referred to herein, may comprise one or more electrical motors. The wording “surroundings  37 ”, as used herein, is intended to encompass surrounding air, such as surrounding air outside of the vehicle  3 , and/or air surrounding one or more radiators  49 ,  51  of the vehicle  3 . The different states of the valves, as described herein, may encompass different opening/closing states, opening/closing positions, opening/closing degrees, or the like. The compressor  24 , as referred to herein, may also be referred to as a working media pump  24 . 
     According to the embodiments illustrated in  FIG. 1 - FIG. 3 , each of the first valve  25  and the second valve  29  comprises a three-way valve. However, according to further embodiments, one of, or both of, the first valve  25  and the second valve  29  may comprise one or more other types of valves. Such one or more other types of valves may be positioned at other positions in the respective circuit  11 ,  15  than depicted in  FIG. 1 - FIG. 3 . Furthermore, as understood from the herein described, the wording “directs coolant” or “control flow of coolant”, as used herein may be an indirect direction of coolant or an indirect control flow of coolant. As an example, according to some embodiments, the first valve  25  is configured to cause coolant to flow through the connecting conduit  11 ′ when in the first state and is configured hinder/block flow of coolant through the connecting conduit  11 ′ when in the second state. Moreover, according to some embodiments, the first valve  25  is configured to cause coolant to flow through the bypass line  11 ″ when the first valve  25  is in the second state. Therefore, throughout this disclosure, the wording “directs coolant” or “control flow of coolant” may be replaced by the wording “cause coolant to flow”. 
     As used herein, the term “comprising” or “comprises” is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.