SE543023C2

SE543023C2 - Cooling System, Powertrain, Vehicle, and Method of controlling Cooling System

Info

Publication number: SE543023C2
Application number: SE1851579A
Authority: SE
Inventors: Ola Hall; Zoltan Kardos
Original assignee: Scania Cv Ab
Priority date: 2018-12-14
Filing date: 2018-12-14
Publication date: 2020-09-29
Also published as: DE102019008255A1; DE102019008255B4; SE1851579A1

Abstract

A cooling system (2) for a vehicle (3) is disclosed. The cooling system (2) comprises a first coolant circuit (6) arranged to cool a first vehicle system (5), a second coolant circuit (23) arranged to cool a second vehicle system (9, 13), a first radiator (46), and a second radiator arrangement (70, 70’). The cooling system (2) further comprises a valve arrangement (8, 10) controllable between a first state in which the first radiator (46) is fluidly connected the first coolant circuit (6) and the second radiator arrangement (70, 70’) is fluidly connected the second coolant circuit (23), and a second state in which the second radiator arrangement (70, 70’) is fluidly connected the first coolant circuit (6) and the first radiator (46) is fluidly connected the second coolant circuit (23). The present disclosure further relates to a powertrain (1), a vehicle (3), and a method (100) of controlling a cooling system (2).

Description

1 Cooling System, Powertrain, Vehicle, and Method of controlling Cooling System TECHNICAL FIELDThe present disclosure relates to a cooling system for a vehicle. The present disclosurefurther relates to a powertrain for a vehicle, a vehicle comprising a powertrain, and a method of controlling a cooling system of vehicle.

BACKGROUND Modern vehicles usually comprise several cooling systems each arranged to cool a vehiclesystem such as a combustion engine, an electric propulsion system, a retarder, a waste heatrecovery system, and the like. Such cooling systems usually comprise one or more radiators arranged to transfer heat from the cooling system to ambient air.

Hybrid electric powertrains use two or more distinct types of power, such as an internalcombustion engine and an electric propulsion system. Generally, an internal combustionengine has poor energy efficiency at lower power output levels and better energy efficiencyat higher power output levels. An electric propulsion system usually has great energyefficiency at low power output levels and at high power output levels, but the storage ofelectric energy in the vehicle is usually insufficient for allowing longer time periods of operation at higher power output levels.

Therefore, some hybrid electric powertrains are configured to switch between electricpropulsion and combustion engine propulsion in dependence of the load such that theelectric propulsion system is operated in low load situations and the combustion engine isstarted and operated in higher load situations. Some hybrid electric powertrains areconfigured to allow simultaneous operation of the electric propulsion system and the combustion engine.

Most modern hybrid electric powertrains are capable of performing regenerative braking, inwhich at least part of the kinetic energy of the vehicle is converted into electric energy duringbraking of the vehicle. The electric energy can be stored in batteries, and/or capacitors, forsubsequent use for propulsion of the vehicle. ln this manner, the total energy efficiency of thevehicle can be improved, especially when driving in areas with many starts and stops, suchas when driving in urban areas. However, the energy saving potential of a hybrid electricpowertrain is limited, or even close to zero, when driving at constant higher speeds, such as during highway driving.

A further advantage of hybrid electric powertrains is that they can allow pure electricpropulsion system in certain areas, such as in city centres, and other areas sensitive toemission of exhaust gases, and/or emission of noise. Therefore, some hybrid electricpowertrains are arranged to shift between pure electric propulsion and pure combustionengine propulsion. This provides an advantage, especially for heavier vehicles, since thevehicle can be operated on pure electric drive when driving in certain areas, such as whendriving in urban areas, and can shift to operation using only the combustion engine whendriving at constant higher speeds, such as during highway driving. ln this manner, thepowertrain can generate low emission levels of exhaust gases and noise in sensitive areas,and the combustion engine is operated in load situations where it is most efficient, i.e. in high load situations. Moreover, the vehicle can be equipped with reasonably sized batteries. ln general, diesel engines have energy efficiency of up to 45% but more typically 30%, andpetrol engines of up to 40%, but more typically 20%. Accordingly, even when the engine isoperating at its point of maximum efficiency, most of the total heat energy released by thefuel consumed is emitted as heat without being turned into useful work, i.e. turning thecrankshaft. A large proportion of the waste heat is emitted in the form of hot exhaust gases.For this reason, some vehicles are equipped with a waste heat recovery system capable ofconverting waste heat into useful work. Most waste heat recovery systems operate in theRankine cycle and comprise a condenser, an exhaust gas heat exchanger, and an expander,wherein steam generated in the exhaust gas heat exchanger is converted into useful work bythe expander. The expander may comprise a turbine or one or more pistons and may beconnected to a shaft of the powertrain to supply useful work thereto. As an alternative, theexpander may be linked to an alternator to generate electricity. ln order to obtain a proper thermal efficiency of the waste heat recovery system, the condenser thereof must be cooled.

The above described vehicle systems are capable of improving energy efficiency of vehicles.However, they are also associated with some drawbacks, such as that they add cost andcomplexity to vehicles. For example, all the above described vehicle systems require cooling.That is, a combustion engine needs a combustion engine cooling system for cooling thecombustion engine, the electrical propulsion system needs a cooling system for coolingelectrical components thereof, and the waste heat recovery system needs a cooling systemfor cooling the condenser thereof. All these cooling systems must be designed in size andcapacity to provide sufficient cooling at the highest power output of the respective system.Thus, in most operating conditions, the size and capacity of the respective cooling system is greater than what is needed given the current power output of the vehicle system. Moreover, 3 all these cooling systems need hoses and one or more radiators arranged to radiate heat, which may pose problems given the limited space available at the vehicle.

Radiators are usually arranged at a front of a vehicle to be subjected to the air flowgenerated during driving of the vehicle. Moreover, radiators can be provided with one ormore cooling fans arranged to blow air through the radiators. ln this manner, an airflowthrough the radiators can be generated also when the vehicle is driving at low speed or is at stand still.

Supercharged combustion engines are usually provided with a charge air cooler arranged tocool air compressed by a supercharger of the combustion engine before the air is ducted toan inlet of the combustion engine. When the supercharger compresses the air, thetemperature of the air increases. By cooling the compressed air, the density of the airincreases and more air can be ducted into cylinders of the engine. ln this manner, the fuel efficiency and the performance of the combustion engine can be improved by cooling the air, and a higher degree of cooling of the air results in higher efficiency of the combustion engine.

Charge air coolers are usually also arranged at the front of a vehicle.

As understood from the above, the limited area at the front of vehicles poses a problem formodern vehicles which comprises various vehicle systems and subsystems having coolingrequirements. ln some cases, due to the limited space, one radiator can be arranged in frontof another radiator. lf so, the cooling efficiency of the radiator downstream may be reduced,because firstly, heat radiated from the radiator upstream may be partially transferred to theradiator downstream, and secondly, the radiator upstream may have a negative impact on the airflow, i.e. may partially hinder airflow, to the radiator downstream.

SUMMARYlt 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 cooling system for avehicle. The cooling system comprises a first coolant circuit arranged to cool a first vehiclesystem and a second coolant circuit arranged to cool a second vehicle system. The coolingsystem further cornpršses a first valve and a second valve. The second vehicle svsterlicornprâses en electric machine alldiei' povxfer electronics. The cooilnﬁl evfslïem furthercoinpršses a return line fluicliv connected to the first *valve an-:š cluctin-:i from coolant iacrtšons el the electric macizlne and lzhe Llevver electronics to the first valve. The cooling system 4 comprises a first radiator and a second radiator arrangement. The cooling system furthercomprises a valve arrangement controllable between a first state in which the first radiator isfluidly connected the first coolant circuit and the second radiator arrangement is fluidlyconnected tmgthe second coolant circuit, and a second state in which the second radiatorarrangement is fluidly connected tmomthe first coolant circuit and the first radiator is fluidlyconnected tgpmthe second coolant circuit such that cootant in the second cooâant circuit flows through the return Eine into 'the first valve and from the 'first valve into the yttrat radiator.

Thereby, a cooling system is provided capable of switching radiator/radiator arrangementused by the first and second coolant circuits simply by controlling the valve arrangement. lnthis manner, in cases where the first vehicle system generates more heat than the secondvehicle system, the first vehicle system can be cooled using the radiator/radiatorarrangement having higher cooling capacity. Likewise, in cases where the second vehiclesystem generates more heat than the first vehicle system, the second vehicle system can be cooled using the radiator/radiator arrangement having higher cooling capacity. ln this manner, the available radiators of the cooling system can be utilized in an efficientmanner, while it is ensured that the first and second vehicle systems obtains sufficientcooling at different operating conditions. Moreover, the first radiator and the second radiatorarrangement can together be designed smaller in size and capacity than would be requiredotherwise for obtaining sufficient cooling of the first and second vehicle systems at their respective maximum heat generating output. ln addition, since each of the first and second vehicle systems can be cooled with highercooling capacity at different operating conditions, the cooling system improves the energy efficiency potential of a powertrain comprising the cooling system.

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

Optionally, the first radiator has a higher cooling capacity than the second radiatorarrangement. Accordingly, due to these features, in cases where the first vehicle systemgenerates more heat than the second vehicle system, the first vehicle system can be fluidlyconnected to the first radiator. Likewise, in cases where the second vehicle systemgenerates more heat than the first vehicle system, the second vehicle system can be cooled using the first radiator. ln this manner, the available radiators of the cooling system is utilized in an efficient manner, while it is ensured that the first and second vehicle systems obtains sufficient cooling at different operating conditions.

Optionally, the first vehicle system comprises a power source of the vehicle Thereby, acooling system is provided allowing the second vehicle system to utilize a radiator of thepower source of the vehicle for cooling the second vehicle system. ln this manner, thesecond vehicle system can be cooled with high cooling efficiency in some operatingconditions in a manner circumventing the need for a radiator of the second cooling systembeing large in size and capacity. Moreover, in some other operating conditions, the secondvehicle system can be cooled using the second radiator arrangement having lower coolingcapacity. Thus, a flexible cooling system is provided which improves the energy efficiency potential of a powertrain comprising the cooling system.

Ithe second vehicle system comprises an electric machine and/or powerelectronics. Thereby, a cooling system is provided which can be capable of using a radiatorof the power source of the vehicle for cooling the electric machine and/or power electronics.

Moreover, as is further explained herein, according to some embodiments of the presentdisclosure, the cooling system is comprised in a powertrain comprising an electric propulsionsystem configured to, at least selectively, provide motive power to a vehicle comprising thepowertrain, wherein the electric machine and the power electronics form part of the electricpropulsion system. According to such embodiments, the powertrain may be referred to as ahybrid electric powertrain, wherein the power source, as referred to herein, may be acombustion engine. The combustion engine and the electric propulsion system of apowertrain rarely operates simultaneously at high power levels. On the contrary, somepowertrains are arranged to operate the combustion engine and the electric propulsionsystem separately, which is the case according to some embodiments of the present disclosure. ln operating conditions where the powertrain is operating the combustion engine at highpower levels and the electric propulsion system is operated at low power levels, or isinactive, there is a high cooling demand of the combustion engine and a low cooling demandof the electric machine and/or power electronics. ln these operating conditions, the valvearrangement may be controlled to the first state in which the first radiator is fluidly connectedto the first coolant circuit so as to cool the combustion engine, and in which the second radiator arrangement is fluidly connected to the second coolant circuit so as to cool the 6 electric machine and/or power electronics. ln this manner, the combustion engine is efficiently cooled at high power levels. ln operating conditions where the powertrain is operating the electric propulsion system athigh power levels and the combustion engine is operated at low power levels, or is inactive,there is a high cooling demand of the electric machine and/or power electronics and a lowcooling demand of the combustion engine. ln these operating conditions, the valvearrangement may be controlled to the second state in which the first radiator is fluidlyconnected to the second coolant circuit so as to cool the electric machine and/or powerelectronics, and in which the second radiator arrangement is fluidly connected to the firstcoolant circuit so as to cool the combustion engine. ln this manner, the electric machineand/or power electronics is efficiently cooled at high power levels using the first radiator, andthe combustion engine can be cooled at lower power outputs levels using the second radiator arrangement.

Accordingly, due to these features, the electric machine and/or power electronics can becooled with higher efficiency in some operating conditions in a manner circumventing theneed for a radiator for the electric machine and/or power electronics being large in size and capacity.

Optionally, the second vehicle system comprises a waste heat recovery system. Thereby, acooling system is provided in which the second radiator arrangement can be used to cool thewaste heat recovery system, and the first radiator can be used to cool the power source,when the power source is operating. Moreover, the need for an additional radiator for coolingthe waste heat recovery system is circumvented. ln this manner, the available radiators ofthe cooling system are utilized in an efficient manner, and the cooling efficiency of the wasteheat recovery system can be improved. Accordingly, due to these features, the coolingsystem further improves the energy efficiency potential of a powertrain comprising the cooling system.

Moreover, when the powertrain is operating the combustion engine at high power levels andthe electric propulsion system is inactive, the cooling demands of the combustion engine andof the condenser of the waste heat recovery system are high. ln these operating conditions,the second coolant circuit of the electric machine and the power electronics is not needed forcooling the electric machine and the power electronics since the electric propulsion system isnot operating. lnstead, in these operating conditions, the condenser of the waste heat recovery system can be cooled by the second radiator arrangement via the second coolant 7 circuit. ln Operating conditions where the powertrain is Operating the electric propulsionsystem and the combustion engine is inactive, there is no need for cooling the condenser ofthe waste heat recovery system because the combustion engine and the waste heatrecovery system are inactive. Accordingly, due to these features, a powertrain is provided inwhich the second radiator arrangement can be used for cooling the electric machine andpower electronics in some operating conditions and can be used for cooling the condenser of the waste heat recovery system in some other operating conditions.

Optionally, the cooling system comprises a control arrangement configured to control thevalve arrangement between the first and second states in dependence of cooling demands ofthe first and second vehicle systems. Thereby, a cooling system is provided capable ofswitching radiator/radiator arrangement used by the first and second coolant circuits simplyby controlling the valve arrangement. ln this manner, in cases where the cooling demand ofthe first vehicle system is higher than the cooling demand of the second vehicle system, thecontrol unit may control the valve arrangement to the first state in which the first radiator isfluidly connected the first coolant circuit and the second radiator arrangement is fluidlyconnected the second coolant circuit. ln cases where the cooling demand of the secondvehicle system is higher than the cooling demand of the first vehicle system, the control unitmay control the valve arrangement to the second state in which the second radiatorarrangement is fluidly connected the first coolant circuit and the first radiator is fluidlyconnected the second coolant circuit. ln this manner, the control unit can ensure that the first and second vehicle systems obtains sufficient cooling at different operating conditions.

Optionally, the valve arrangement comprises a first valve fluidly connected to the first andsecond coolant circuits and to the first radiator and the second radiator arrangementupstream of the first radiator and the second radiator arrangement, and a second valvefluidly connected to the first and second coolant circuits and to the first radiator and thesecond radiator arrangement, downstream of the first radiator and the second radiatorarrangement. Thereby, a simple and efficient valve arrangement is provided capable of switching radiator/radiator arrangement used by the first and second coolant circuits.

Optionally, the first and second valves are arranged to be controlled between the first andsecond states simultaneously. Thereby, a valve arrangement is provided capable ofswitching radiator/radiator arrangement used by the first and second coolant circuits in aquick manner, and pressure peaks in the first and second coolant circuits are avoided.Moreover, conditions are provided for using one actuator for controlling the valve arrangement between the first and second states.

Optionally, the first radiator and the second radiator arrangement are configured to besubjected to a flow of air having a flow direction, and wherein the second radiatorarrangement is arranged in front of the first radiator seen in the flow direction. Thereby, acooling system is provided capable of utilizing available space at a vehicle in an efficientmanner. Moreover, it is ensured that the second radiator arrangement can cool coolant in an efficient manner.

Optionally, the second radiator arrangement comprises a first radiator unit and a secondradiator unit. Thereby, the second radiator arrangement can be utilized to cool the first vehicle system and the second vehicle system in an efficient manner.

Optionally, a coolant outlet of the first radiator unit is fluidly connected to a coolant inlet of thesecond radiator unit. Thereby, the second radiator arrangement can be utilized to cool thefirst vehicle system and the second vehicle system in an efficient manner. Furthermore, sincefirst radiator unit comprises a coolant outlet fluidly connected to a coolant inlet of the secondradiator unit, the second radiator unit will have a lower temperature than the first radiator unit during cooling of a vehicle system.

Optionally, the cooling system further comprises a third coolant circuit arranged to cool athird vehicle system, and wherein the third coolant circuit comprises a third radiator arrangedin front of the first radiator seen in the flow direction. Thereby, a cooling system is provided capable of cooling a third vehicle system in an efficient manner.

Optionally, the third vehicle system comprises a battery. Thereby, a cooling system is provided capable of cooling a battery in an efficient manner.

According to a second aspect of the invention, the object is achieved by a powertrain for avehicle, wherein the powertrain comprises a first vehicle system and a second vehiclesystem, and wherein the powertrain comprises a cooling system according to some embodiments of the present disclosure.

Since the powertrain comprises a cooling system according to some embodiments, apowertrain is provided capable of switching radiator/radiator arrangement used to cool thefirst and second vehicle systems simply by controlling the valve arrangement of the coolingsystem. ln this manner, in cases where the first vehicle system generates more heat than the second vehicle system, the first vehicle system can be cooled using to the radiator/radiator 9 arrangement having higher cooling capacity. Likewise, in cases where the second vehiclesystem generates more heat than the first vehicle system, the second vehicle system can be cooled using the radiator/radiator arrangement having higher cooling capacity. ln this manner, the available radiators of the cooling system are utilized in an efficientmanner, while it is ensured that the first and second vehicle systems obtains sufficientcooling at different operating conditions. Moreover, the first radiator and the second radiatorarrangement can together be designed smaller in size and capacity than would be requiredotherwise for obtaining sufficient cooling of the first and second vehicle systems at their respective maximum heat generating output. ln addition, since each of the first and second vehicle systems can be cooled with highercooling capacity at different operating conditions, the energy efficiency potential of the powertrain is improved.

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

Optionally, the powertrain is arranged to operate the first vehicle system and the secondvehicle system separately. ln this manner, in cases where the first vehicle system isoperating, the first vehicle system can be cooled using the radiator/radiator arrangementhaving higher cooling capacity. Likewise, in cases where the second vehicle system isoperating, the second vehicle system can be cooled using the radiator/radiator arrangement having higher cooling capacity. ln this manner, the available radiators of the cooling system are utilized in an efficientmanner, while it is ensured that the first and second vehicle systems obtains sufficientcooling. Moreover, the first radiator and the second radiator arrangement can together bedesigned smaller in size and capacity than would be required otherwise for obtainingsufficient cooling of the first and second vehicle systems at their respective maximum heat generating output.

Optionally, the powertrain further comprises a charge air cooler, wherein the first radiator, thesecond radiator arrangement, and the charge air cooler are configured to be subjected to aflow of air having a flow direction, and wherein the charge air cooler is arranged in front of the first radiator, and the second radiator arrangement is arranged in front of the charge air cooler, seen in the flow direction. Thereby, a cooling system is provided capable of utilizingavailable space at a vehicle in an efficient manner. Moreover, it is ensured that the second radiator arrangement can cool coolant in an efficient manner.

Optionally, the charge air cooler comprises an inflow half portion and an outflow half portion,the inflow half portion having a higher temperature than the outflow half portion duringoperation of the charge air cooler, and wherein the second radiator arrangementsuperimposes a greater proportion of the inflow half portion than the outflow half portion seenin the flow direction. Thereby, it is ensured that the second radiator arrangement can coolcoolant in an efficient manner, while it is ensured that the second radiator arrangement willhave a low impact on the cooling efficiency of the charge air cooler. This because the secondradiator arrangement superimposes the inflow half portion having a higher temperature thanthe outflow half portion during operation of the charge air cooler, and because a greaterproportion of the outflow half portion, which is cooler than the inflow half portion, is not faced with a radiator superimposing portions thereof.

Optionally, the charge air cooler comprises an inflow half portion and an outflow half portion,the inflow half portion having a higher temperature than the outflow half portion duringoperation of the charge air cooler, and wherein the third radiator superimposes a greaterproportion of the inflow half portion than the outflow half portion seen in the flow direction.Thereby, it is ensured that the third radiator can cool coolant in an efficient manner, while it isensured that the third radiator will have a low impact on the cooling efficiency of the chargeair cooler. This because the third radiator superimposes the inflow half portion having ahigher temperature than the outflow half portion during operation of the charge air cooler,and because a greater proportion of the outflow half portion, which is cooler than the inflow half portion, is not faced with a radiator superimposing portions thereof.

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

Since the vehicle comprises a powertrain according to some embodiments, a vehicle isprovided in which available radiators of the vehicle can be utilized in an efficient manner,while it is ensured that a first and second vehicle system of the vehicle obtains sufficientcooling at different operating conditions. Moreover, radiators of the vehicle can be designedsmaller in size and capacity than would be required othenNise for obtaining sufficient coolingof the first and second vehicle systems at their respective maximum heat generating output. ln addition, a vehicle is provided with improved energy efficiency potential. 11 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 is achieved.

According to a fourth aspect of the invention, the object is achieved by a method ofcontrolling a cooling system of vehicle. The cooling system comprises a first coolant circuit arranged to cool a first vehicle system, a valve arranqeirtent comprising a first valve and a second valve, a second coolant circuit arranged to cool a second vehicle system contgrlsing an electric machine andler eevver electronics. a return line fluidly Connecta-cl to the tirsl xfalve, rluciine coolant 'frem eeelanl pertiens of the electric machine and lite efwver electronics to the first valve, a first radiator, a second radiator arrangement, wherein the method comprises: - selectively controlling the valve arrangement, to a first state in which the firstradiator is fluidly connected lgthe first coolant circuit and the second radiatorarrangement, is fluidly connected lgthe second coolant circuit, and - selectively controlling the valve arrangement, to a second state in which thesecond radiator arrangement, is fluidly connected t_ valve and from the first vsilve inte the first radiator.

Thereby, a method is provided capable of switching radiator/radiator arrangement used bythe first and second coolant circuits in a simple and efficient manner. As a result thereof, theavailable radiators of the cooling system can be utilized in an efficient manner, while it isensured that the first and second vehicle systems obtains sufficient cooling at differentoperating conditions. Moreover, as a result of the method, the first radiator and the secondradiator arrangement can together be designed smaller in size and capacity than would berequired othenNise for obtaining sufficient cooling of the first and second vehicle systems at their respective maximum heat generating output. ln addition, since each of the first and second vehicle systems can be cooled with highercooling capacity at different operating conditions, the method improves the energy efficiency potential of a powertrain comprising the cooling system. 12 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 is achieved.

Optionally, the method further comprises: - determining cooling demands of the first and second vehicle systems, and - controlling the valve arrangement between the first and second states independence of the determined cooling demands of the first and second vehicle systems.

Thereby, a method is provided capable of ensuring that the first and second vehicle systemsobtains sufficient cooling at different operating conditions. Accordingly, in cases where thecooling demand of the first vehicle system is higher than the cooling demand of the secondvehicle system, the valve arrangement may be controlled to the first state in which the firstradiator is fluidly connected the first coolant circuit and the second radiator arrangement isfluidly connected the second coolant circuit. ln cases where the cooling demand of thesecond vehicle system is higher than the cooling demand of the first vehicle system, thevalve arrangement may be controlled to the second state in which the second radiatorarrangement is fluidly connected the first coolant circuit and the first radiator is fluidly connected the second coolant circuit.

Optionally, the valve arrangement comprises a first valve and a second valve, and whereinthe method further comprises:- controlling the first and second valves between the first and second states simultaneously.

Thereby, a method is provided capable of switching radiator/radiator arrangement used bythe first and second coolant circuits in a quick manner, and pressure peaks in the first andsecond coolant circuits are avoided. Moreover, conditions are provided for using oneactuator for controlling the valve arrangement betvveen the first and second states.

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 13 Various aspects of the invention, including its particular features and advantages, will bereadily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which: Fig. 1 schematically illustrates a powertrain, according to some embodiments, with a valvearrangement in a first state, Fig. 2 illustrates the powertrain illustrated in Fig. 1, with the valve arrangement in a secondstate, Fig. 3 illustrates a side view of a radiator assembly of the powertrain according to theembodiments illustrated in Fig. 1 and Fig. 2, Fig. 4 illustrates a front view of the radiator assembly illustrated in Fig. 3, Fig. 5 illustrates a vehicle, according to some embodiments, and Fig. 6 illustrates a method of controlling a cooling system of vehicle.

DETAILED DESCRIPTIONAspects 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 described in detail for brevity and/or clarity.

Fig. 1 schematically illustrates a powertrain 1, according to some embodiments. As is furtherexplained herein, according to the illustrated embodiments, the powertrain 1 is a hybridelectric powertrain 1 configured provide motive power to a vehicle comprising the powertrain1. The powertrain 1 comprises a first vehicle system 5 and a second vehicle system 9, 13.The powertrain 1 comprises a cooling system 2. The cooling system 2 comprises a firstcoolant circuit 6 arranged to cool the first vehicle system 5 and a second coolant circuit 23arranged to cool the second vehicle system 9, 13. The first coolant circuit 6 comprises acoolant pump 49 arranged to pump coolant through the first coolant circuit 6. The coolantpump 49 may be powered by an electric motor or may be powered by the first vehicle system5 via a belt and pulley arrangement, or the like. Moreover, the second coolant circuit 23comprises a coolant pump 24 arranged to pump coolant through the second coolant circuit 23. The coolant pump 24 may be powered by an electric motor.

Moreover, the cooling system 2 comprises a first radiator 46, and a second radiatorarrangement 70, 70”. The first radiator 46 has a higher cooling capacity than the secondradiator arrangement 70, 70”. According to the illustrated embodiments, the second radiator arrangement 70, 70' comprises two radiators 70, 70' arranged in series. The two radiators 14 70, 70' may be combined in a u-flow radiator or similar. According to further embodiments, the radiator arrangement 70, 70' may comprise one radiator.

According to the illustrated embodiments, the first vehicle system 5 comprises a powersource 5. The power source 5 may be an internal combustion engine such as for example acompression ignition engine, such as a diesel engine, or an Otto engine with a spark-ignitiondevice, wherein the Otto engine may be configured to run on gas, petrol, alcohol, similarfuels, or combinations thereof. According to further embodiments, the power source 5 may be another type of power source, such as an electric machine, a fuel cell, or the like.

According to some embodiments, the powertrain 1 is arranged to operate the first vehiclesystem 5 and the second vehicle system 9, 13 separately. As mentioned above, according tothe illustrated embodiments, the powertrain 1 is a hybrid electric powertrain 1. Thepowertrain 1 comprises an electric propulsion system 9, 11, 13 configured to, at leastselectively, provide motive power to a vehicle comprising the powertrain 1. According to theillustrated embodiments, the electric propulsion system 9, 11, 13 comprises an electricmachine 9, a battery 11, and power electronics 13. The battery 11 is for electric propulsion ofthe vehicle 3 and is arranged to supply electricity to the electric machine 9 by an amount controlled by the power electronics 13.

According to the illustrated embodiments, the second vehicle system 9, 13, as referred toherein, comprises the electric machine 9 and the power electronics 13 of the electricpropulsion system 9, 11, 13. Thus, according to the illustrated embodiments, the second coolant circuit 23 is arranged to cool the electric machine 9 and the power electronics 13.

According to the present disclosure, the cooling system 2 further comprises a valvearrangement 8, 10. The valve arrangement 8, 10 is controllable between a first state and asecond state. ln Fig. 1, the valve arrangement 8, 10 is illustrated in the first state. ln the firststate, the valve arrangement 8, 10 fluidly connects the first radiator 46 to the first coolantcircuit 6 and the second radiator arrangement 70, 70' to the the second coolant circuit 23. lnthis manner, the first radiator 46 can be used to cool coolant in the first coolant circuit 6 andthe second radiator arrangement 70, 70' can be used to cool coolant in the second coolantcircuit 23. Accordingly, when the valve arrangement 8, 10 is in the first state, the first radiator46 can be used to cool the first vehicle system 5 and the second radiator arrangement 70, 70' can be used to cool the second vehicle system 9, 13.

Fig. 2 illustrates the powertrain 1 illustrated in Fig. 1, with the valve arrangement 8, 10 in thesecond state. ln the second state, the valve arrangement 8, 10 fluidly connects the firstradiator 46 to the second coolant circuit 23 and the second radiator arrangement 70, 70' tothe first coolant circuit 6. ln this manner, the first radiator 46 can be used to cool coolant inthe second coolant circuit 23 and the second radiator arrangement 70, 70' can be used tocool coolant in the first coolant circuit 6. Accordingly, when the valve arrangement 8, 10 is inthe second state, the first radiator 46 can be used to cool the second vehicle system 9, 13 and the second radiator arrangement 70, 70' can be used to cool the first vehicle system 5.

According to the illustrated embodiments, the valve arrangement 8, 10 comprises a firstvalve 8 fluidly connected to the first and second coolant circuits 6, 23 and to the first radiator46 and the second radiator arrangement 70, 70', upstream of the first radiator 46 and thesecond radiator arrangement 70, 70”. Moreover, the valve arrangement 8, 10 comprises asecond valve 10 fluidly connected to the first and second coolant circuits 6, 23 and to the firstradiator 46 and the second radiator arrangement 70, 70', downstream of the first radiator 46and the second radiator arrangement 70, 70”. According to the illustrated embodiments, thefirst and second valves 8, 10 are arranged to be controlled between the first and secondstates simultaneously. Due to these features, conditions are provided for using one actuatorfor controlling the valve arrangement 8, 10 between the first and second states. Even thoughthe first and second valves 8, 10 are illustrated at a distance from each other in Fig. 1 andFig. 2, they may be arranged adjacent to each other and may be controlled using one controlshaft connected to a respective valve body 8', 10' of the respective first and second valves 8, . According to such embodiments, the control shaft may be moved using one actuator.

According to the illustrated embodiments, the second vehicle system 9, 13 comprises awaste heat recovery system 7. The waste heat recovery system 7 comprises an expander15, a condenser 17, an expansion tank 83, a working media pump 85, and a heat collector81. The heat collector 81 may also be referred to as a boiler or an evaporator. The workingmedia pump 85 is arranged to pump working media through the waste heat recovery system7. The heat collector 81 may for example be arranged in an exhaust pipe of the powersource 5 and may be arranged to transfer heat from exhaust gasses of the power source 5 tothe working media of the waste heat recovery system 7. ln the heat collector 81, the workingmedia is heated to a temperature in which the working media evaporates from liquid phaseinto gaseous phase. The gaseous working media is transferred to the expander 15. ln theexpander 15, the temperature and the pressure of the working media is partially convertedinto useful work. According to the illustrated embodiments, a rotor of the expander 15 is mechanically connected to a crankshaft of the power source 5, via a transmission 87. 16 According to further embodiments, the expander 15 may provide useful work in another manner, such as for example by driving an alternator producing electricity.

The working media of the waste heat recovery system 7 flows out from the expander 15 andinto the condenser 17. ln the condenser 17, the temperature of the working media is furtherreduced, and gaseous working media is condensed back into liquid phase. From thecondenser 17, the working media is pumped to the heat co||ector 81 by the working mediapump 85. The expansion tank 83 acts as a reservoir holding working media and acts as apressure reservoir for the working media in the waste heat recovery system 7, whichfacilitates condensation of working media also in cases where it is difficult to lower the temperature of the working media in a sufficient manner.

According to the illustrated embodiments, the powertrain 1 comprises a condenser coolantcircuit 21 arranged to cool the condenser 17. Accordingly, the condenser 17 is arranged tobe cooled by coolant flowing through the condenser coolant circuit 21. The condensercoolant circuit 21 comprises a coolant pump 43 arranged to pump coolant through thecondenser coolant circuit 21. The coolant pump 43 may be powered by an electric motor.Furthermore, the powertrain 1 comprises a first heat exchanger 27 configured to exchangeheat between the condenser coolant circuit 21 and the second coolant circuit 23. As can beseen in Fig. 1 and Fig. 2, the first heat exchanger 27 is arranged upstream of the condenser17 in the condenser coolant circuit 21. ln this manner, coolant flowing through the condensercoolant circuit 21 can be further cooled, by the first heat exchanger 27, before the coolant isflowing to the condenser 17. Accordingly, the second coolant circuit 23 can be utilized to cool the condenser 17 in an efficient manner.

The second coolant circuit 23 comprises a first valve unit 31. The first valve unit 31 isarranged to regulate the flow of coolant through the first heat exchanger 27. Moreover, thesecond coolant circuit 23 comprises a first coolant branch 33. The first heat exchanger 27 isarranged in the first coolant branch 33 of the second coolant circuit 23. According to theembodiments illustrated in Fig. 1 and Fig. 2, the first coolant branch 33 comprises a branchinlet 35 arranged upstream of the electric machine 9 and the power electronics 13. ln thismanner, heat can be exchanged from the condenser coolant circuit 21 to the second coolantcircuit 23 without significantly affecting the temperature and the cooling performance of theelectric machine 9 and the power electronics 13. Furthermore, it is ensured that coolanthaving a low temperature is supplied to the first heat exchanger 27. Moreover, according to the illustrated embodiments, the second coolant circuit 23 is arranged to cool a cabin heater 17 condenser 90, an electrical air Compressor system 92, and a condenser 94 of a battery refrigeration circuit 93.

According to the illustrated embodiments, the first valve unit 31 is positioned at the branchin|et 35 of the first coolant branch 33. The first valve unit 31 comprises a first outlet 31' fluidlyconnected to coolant portions of the electric machine 9 and the power electronics 13 and asecond outlet 31” fluidly connected to the branch in|et 35. Coolant is ducted from coolantportions of the electric machine 9 and the power electronics 13 via a return line 34. Thereturn line 34 is fluidly connected to the first valve 8 of the valve arrangement 8, 10 in amanner bypassing the first heat exchanger 27. According to the illustrated embodiments, thefirst valve unit 31 is an electronically controlled valve which can be controlled to a first statein which the first valve unit 31 supplies coolant to the first outlet 31' and blocks coolant fromflowing through the second outlet 31”, and a second state in which the first valve unit 31supplies coolant to the second outlet 31” and blocks coolant from flowing through the firstoutlet 31”. Furthermore, the first valve unit 31 may allow a gradual control to states betweenthe first and second states to allow a gradual control of flow through the first and secondoutlets 31 ', 31”. ln this manner, the flow rate of coolant flowing through the first heat exchanger 27 can be regulated with high degree of control.

Furthermore, as explained above, it is rare that the power source 5 and the electricpropulsion system 9, 11, 13 operates simultaneously, or at least with high power output fromboth systems simultaneously. ln addition, according to some embodiments of the presentdisclosure, the powertrain 1 is arranged to operate the power source 5 and the electricpropulsion system 9, 11, 13 separately. Thus, in operating conditions where the powertrain 1is operating the power source 5 and the electric propulsion system 9, 11, 13 is inactive, thecomponents 9, 11, 13 of the electric propulsion system 9, 11, 13 generates no heat and haveno need for cooling. ln operating conditions where the powertrain 1 is operating the electricpropulsion system 9, 11, 13 and the power source 5 is inactive, the power source 5 and the condenser 17 of the waste heat recovery system 7 have no need for cooling.

As understood from the above, in operating conditions where the powertrain 1 is operatingthe electric propulsion system 9, 11, 13 and the power source 5 is inactive, the first valve unit31 may be controlled to positions where the first valve unit 31 mainly controls coolant flow tothe first outlet 31 '_ ln this manner, the electric machine 9 and the power electronics 13 areefficiently cooled by the second coolant circuit 23. However, if the cooling demand of theelectric machine 9 and the power electronics 13 is low, the first valve unit 31 may also be controlled to positions where the first valve unit 31 controls coolant flow to the second outlet 18 31” so as to totally or partially bypass the electric machine 9 and the power electronics 13. lnoperating conditions where the powertrain 1 is operating the power source 5 and the electricpropulsion system 9, 11, 13 is inactive, the first valve unit 31 may be controlled to positionswhere the first valve unit 31 mainly controls coolant flow to the second outlet 31”. ln thismanner, the condenser 17 of the waste heat recovery system 7 is efficiently cooled by the second coolant circuit 23.

According to the illustrated embodiments, the cooling system 2 further comprises a thirdcoolant circuit 25. The third coolant circuit 25 is arranged to cool a third vehicle system 11,which according to the illustrated embodiments is a battery 11. The third coolant circuit 25 isthus arranged to cool the battery 11. The third coolant circuit 25 comprises a coolant pump26 arranged to pump coolant through the third coolant circuit 25. The coolant pump 26 maybe powered by an electric motor. The third coolant circuit 25 further comprises a thirdradiator 74 arranged to radiate heat from, i.e. cool, coolant in the third coolant circuit 25.Moreover, according to the illustrated embodiments, the powertrain 1 comprises a secondheat exchanger 29 arranged to exchange heat between the condenser coolant circuit 21 andthe third coolant circuit 25. As can be seen in Fig. 1 and Fig. 2, the second heat exchanger29 is arranged upstream of the condenser 17 in the condenser coolant circuit 21. ln thismanner, coolant flowing through the condenser coolant circuit 21 can be further cooled, bythe second heat exchanger 29, before the coolant is flowing to the condenser 17.Accordingly, the third coolant circuit 25 can be utilized to cool the condenser 17 in an efficient mannef.

The third coolant circuit 25 comprises a second valve unit 37. The second valve unit 37 isarranged to regulate the flow of coolant through the second heat exchanger 29. Moreover,the third coolant circuit 25 comprises a second coolant branch 39, wherein the second heatexchanger 29 is arranged in the second coolant branch 39. The second coolant branch 39comprises a branch inlet 41 arranged upstream of the battery 11 and a branch outletdownstream of the battery 11. ln this manner, heat can be exchanged from the condensercoolant circuit 21 to the third coolant circuit 25 without significantly affecting the temperature and the cooling performance of the battery 11.

Moreover, according to the illustrated embodiments, the second valve unit 37 is positioned atthe branch inlet 41 of the second coolant branch 39 and comprises a first outlet 37' fluidlyconnected to coolant portions of the battery 11 and a second outlet 37” fluidly connected tothe branch inlet 41 of the second coolant branch 39. According to the illustrated embodiments, the second valve unit 37 is an electronically controlled valve which can be 19 controlled to a first state in which the second valve unit 37 supplies coolant to the first outlet37' and blocks coolant from flowing through the second outlet 37”, and a second state inwhich the second valve unit 37 supplies coolant to the second outlet 37” and blocks coolantfrom flowing through the first outlet 37”. Furthermore, the second valve unit 37 may allow agradual control of flow through the first and second outlets 37', 37”. ln this manner, the flowrate of coolant flowing through the second heat exchanger 29 can be regulated with high degree of control. ln operating conditions where the powertrain 1 is operating the electric propulsion system 9,11, 13 and the power source 5 is inactive, the second valve unit 37 may be controlled topositions where the second valve unit 37 mainly controls coolant flow to the first outlet 37”. lnthis manner, the battery 11 can be efficiently cooled by the third coolant circuit 25. However,if the cooling demand of the battery 11 is low, the second valve unit 37 may also becontrolled to positions where the second valve unit 37 controls coolant flow to the secondoutlet 37” so as to totally or partially bypass the battery 11. Moreover, in operating conditionswhere the powertrain 1 is operating the power source 5 and the electric propulsion system 9,11, 13 is inactive, the second valve unit 37 may be controlled to positions where the secondvalve unit 37 mainly controls coolant flow to the second outlet 37”. ln this manner, thecondenser 17 of the waste heat recovery system 7 is efficiently cooled by the third coolant circuit 25.

According to some embodiments of the present disclosure, the first valve 31 may bepositioned at another position in the second coolant circuit 23, than at the branch inlet 35 ofthe first coolant branch 33, and still achieve all, or some of, the above described functions.As an example, the first valve 31 may be positioned at a branch outlet of the first coolantbranch 33. Likewise, the second valve 37 may be positioned at another position in the thirdcoolant circuit 25, than at the branch inlet 41 of the second coolant branch 39, and stillachieve all, or some of, the above described functions. As an example, the second valve 37 may be positioned at a branch outlet of the second coolant branch 39.

As indicated above, according to the illustrated embodiments, the powertrain 1 furthercomprises a battery refrigeration circuit 93. The battery refrigeration circuit 93 is arranged tofurther lower the temperature of coolant in the third coolant circuit 25. The batteryrefrigeration circuit 93 comprises a compressor 98, a condenser 94, an expansion valve 95,and an evaporator 96. The evaporator 96 may also be referred to as a chiller. Thecompressor 98 compresses working media in the battery refrigeration circuit 93. The compressed working media is partially cooled by the condenser 94. Then the working media is expanded by the expansion valve 95. As a result, the temperature of the working media issignificantly reduced. The working medium cools coolant of the third coolant circuit 25 uponevaporation in the evaporator 96. ln this manner, it can be ensured that the battery 11 issufficiently cooled also in high load situations and in situations with high ambient temperatures.

As can be seen in Fig. 1 and Fig. 2, the evaporator 96 of the battery refrigeration circuit 93 isarranged upstream of the branch inlet 41 of the second coolant branch 39. ln this manner,the battery refrigeration circuit 93 can also be utilized for further cooling the condenser 17 ofthe waste heat recovery system 7. Thereby, condensation of working medium in thecondenser 17 can be further ensured even at higher load situations of the power source 5 and of the waste heat recovery system 7.

Moreover, as can be seen in Fig. 1 and Fig. 2, the second coolant circuit comprises a heater44 arranged in a bypass line bypassing the third radiator 74 of the third coolant circuit 25.The heater 44 can be used to heat coolant of the third coolant circuit 25 in order to heat the battery 11 when needed, such as at cold starts at lower ambient temperatures.

According to the embodiments illustrated in Fig. 1 and Fig. 2, the condenser coolant circuit21 is separated from the first coolant circuit 6. That is, according to the embodimentsillustrated in Fig. 1 and Fig. 2, the condenser coolant circuit 21 has no fluid connection to thefirst coolant circuit 6. ln this manner, heat exchange can occur between the condenser 17 ofthe waste heat recovery system 7 and the first and second heat exchangers 27, 29 in amanner independent of temperature of coolant in the first coolant circuit 6, and thus also in amanner independent of the cooling of the power source 5. Accordingly, due to thesefeatures, the condenser 17 can be cooled using the second and third coolant circuits 23, 25in a manner independent of the cooling of the power source 5 and different temperatures ofcoolant is allowed in the first coolant circuit 6 and in the condenser coolant circuit 21.Moreover, conditions are provided for using different types of coolant in the condenser coolant circuit 21 and the first coolant circuit 6.

According to the embodiments illustrated in Fig. 1 and Fig. 2, the first coolant circuit 6 is aconventional engine coolant circuit 6. Moreover, according to the illustrated embodiments,the first radiator 46 is a conventional engine radiator. The first coolant circuit 6 comprises aradiator line 51 arranged to conduct coolant to the first valve 8 of the valve arrangement 8,10 and a bypass line 53 arranged to conduct coolant past the first valve 8 of the valve arrangement 8, 10. Moreover, the first coolant circuit 6 comprises a first valve device 55 21 arranged to receive coolant from a coolant line 57 of the first coolant circuit 6 and direct thecoolant to the radiator line 51 and the bypass line 53. The first valve device 55 may comprisea conventional thermostat. As indicated in Fig. 1 and Fig. 2, the coolant line 57 may be fluidlyconnected to a coolant outlet of the power source 5. Moreover, as indicated in Fig. 1 and Fig.2, the first coolant circuit 6 comprises a radiator outlet line 59 arranged to conduct coolant flow from the first radiator 46 to the second valve 10 of the valve arrangement 8, 10. ln this manner, in situations where the first valve device 55 directs coolant to the radiator line51, such as when coolant at the first valve device 55 is higher than a threshold temperature,coolant can flow from the coolant line 57, through the radiator line 51 into the first valve 8 ofthe valve arrangement 8, 10. When the valve arrangement 8, 10 is in the first state, as isillustrated in Fig. 1, the coolant flows from the first valve 8 into the first radiator 46, and outfrom the first radiator 46 through the radiator outlet line 59 into the second valve 10 of thevalve arrangement 8, 10. When the valve arrangement 8, 10 is in the first state, the coolant isflowing from the second valve 10 to a coolant inlet of the coolant pump 49 of the first coolantcircuit 6. ln this manner, coolant from the first coolant circuit 6 can be pumped through the first radiator 46 when the valve arrangement 8, 10 is in the first state.

Moreover, when the valve arrangement 8, 10 is in the first state, as is illustrated in Fig. 1,coolant in the second coolant circuit 23 flows through the return line 34 into the first valve 8and from the first valve 8 into the second radiator arrangement 70, 70', and out from thesecond radiator arrangement 70, 70' into the second valve 10 of the valve arrangement 8,10. Moreover, when the valve arrangement 8, 10 is in the first state, the coolant is flowingfrom the second valve 10 to a coolant inlet of the coolant pump 24 of the second coolantcircuit 23. ln this manner, coolant from the second coolant circuit 23 can be pumped throughthe second radiator arrangement 70, 70' when the valve arrangement 8, 10 is in the first state.

When the valve arrangement 8, 10 is in the second state, as is illustrated in Fig. 2, coolantflowing through the radiator line 51 of the first coolant circuit flows into the first valve 8 andout from the first valve 8 into the second radiator arrangement 70, 70', and out from thesecond radiator arrangement 70, 70' into the second valve 10 of the valve arrangement 8,10. Moreover, when the valve arrangement 8, 10 is in the second state, the coolant is flowingfrom the second valve 10 to a coolant inlet of the coolant pump 49 of the first coolant circuit6. ln this manner, coolant from the first coolant circuit 6 can be pumped through the second radiator arrangement 70, 70' when the valve arrangement 8, 10 is in the second state. 22 Moreover, when the valve arrangement 8, 10 is in the second state, as is illustrated in Fig. 2,coolant in the second coolant circuit 23 flows through the return line 34 into the first valve 8and from the first valve 8 into the first radiator 46, and out from the first radiator 46 throughthe radiator outlet line 59 into the second valve 10 of the valve arrangement 8, 10. When thevalve arrangement 8, 10 is in the second state, the coolant is flowing from the second valve10 to a coolant inlet of the coolant pump 24 of the second coolant circuit 23. ln this manner,coolant from the second coolant circuit 23 can be pumped through the first radiator 46 when the valve arrangement 8, 10 is in the second state.

According to some embodiments of the present disclosure, the valve arrangement 8, 10 iscontrollable to states between the first and second states, i.e. to states in which the firstradiator 46 is fluidly connected to the first coolant circuit 6 as well as to the second coolantcircuit 23, and in which the second radiator arrangement 70, 70' is fluidly connected to thefirst coolant circuit 6 as well as to the second coolant circuit 23. ln this manner the firstvehicle system 5 and/or the second vehicle system 9, 13 can be cooled with even higher cooling efficiency.

According to the illustrated embodiments, the cooling system 2 comprises a controlarrangement 30. The control arrangement 30 is configured to control the valve arrangement8, 10 between the first and second states in dependence of cooling demands of the first andsecond vehicle systems 5, 9, 13. The control arrangement 30 illustrated in Fig. 1 and Fig. 2may be configured to control operation of one or more further arrangements and/or systems,such as one or more pumps 24, 26, 43, 49, 85 of the powertrain 1, and/or configured tocontrol opening states of one or more valves 31, 37, 55 of the powertrain 1. The controlarrangement 30 may be configured to control operation of the one or more pumps 24, 26, 43,49, 85, and/or to control opening states of one or more valves 8, 10, 31, 37, 55 independence of the operating state of the power source 5, the waste heat recovery system 7,and/or the electric propulsion system 9, 11, 13, as well as in dependence of a current, orpredicted, cooling demand of one or more components 5, 9, 11, 13, 17 of the powertrain 1.The control arrangement 30 illustrated in Fig. 1 and Fig. 2 may thus be connected to suchfurther arrangements and/or systems. However, such connections are not illustrated in Fig. 1 and Fig. 2 for the reason of brevity and clarity.

According to the embodiments illustrated in Fig. 1 and Fig. 2, all radiators 70, 70', 74 of thesecond and third coolant circuits 23, 25 of the electric propulsion system 9, 11, 13 arearranged in front of the first radiator 46. Moreover, the powertrain 1 comprises a charge air cooler 72 arranged between the radiators 70, 70', 74 of the second and third coolant circuits 23 23, 25 and the first radiator 46. The charge air cooler 72 is arranged to cool air compressedby a supercharger of the power source 5 before the air is ducted to an inlet of the powersource 5. The supercharger is not illustrated in Fig. 1 and Fig. 2 for the reason of brevity andclarity. The fuel efficiency and the performance of the power source 5 is improved by cooling the inlet air of the power source 5 in the charge air cooler 72.

Fig. 3 i||ustrates a side view of a radiator assembly 4 of the powertrain 1 according to theembodiments illustrated in Fig. 1 and Fig. 2. The radiator assembly 4 comprises the firstradiator 46, the second radiator arrangement 70, 70', the third radiator 74, and the charge air cooler 72. The charge air cooler 72 may also be referred to as an intercooler.

The radiator assembly 4 is configured to be subjected to a flow of air having a flow directiond, i.e. an air flow direction d. As is further explained herein, the radiator assembly 4 may beconfigured to be arranged at a front area of a vehicle to be subjected to an airflow duringdriving of the vehicle. According to such embodiments, the flow direction d may be oppositeto a forward direction of travel of the vehicle comprising the radiator assembly 4. As analternative, or in addition, the radiator assembly 4 may comprise one or more cooling fansarranged to selectively blow air through the radiator assembly 4 in the flow direction d.Throughout this disclosure, the wording “flow direction d” may be replaced by the wording “air flow direction d”.

According to the illustrated embodiments, the second radiator arrangement 70, 70' isarranged in front of the first radiator 46 seen in the flow direction d, i.e. upstream of theengine radiator 46 relative the flow direction d. Moreover, the second radiator arrangement70, 70' comprises a first radiator unit 70 and a second radiator unit 70', wherein a coolantoutlet 77 of the first radiator unit 70 is fluidly connected to a coolant inlet 77' of the secondradiator unit 70”. Since the second radiator unit 70' is arranged downstream of the firstradiator unit 70, the second radiator unit 70' will have a lower temperature than the first radiator unit 70 during operation of the radiator assembly 4.

Moreover, according to the illustrated embodiments, the charge air cooler 72 is arranged infront of the first radiator 46, and the second radiator arrangement 70, 70' and the third radiator 74 are arranged in front of the charge air cooler 72, seen in the flow direction d.

Fig. 4 i||ustrates a front view of the radiator assembly 4 illustrated in Fig. 3. ln Fig. 4, theradiator assembly 4 is illustrated as seen in the flow direction d indicated in Fig .1. As indicated in Fig. 4, the charge air cooler 72 comprises an inflow half portion 72' and an 24 outflow half portion 72". The inflow half portion 72' comprises an inlet and the outflow halfportion 72” comprises an outlet. During operation of the charge air cooler 72, compressedgas is flowing into the charge air cooler 72 via the inlet and out from the charge air cooler 72via the outlet. ln the charge air cooler 72, the compressed air is flowing from the inflow halfportion 72' to the outflow half portion 72". The compressed air is cooled when flowingthrough the charge air cooler 72. Therefore, the inflow half portion 72' will have a higher temperature than the outflow half portion 72" during operation of the charge air cooler 72.

As can be seen in Fig. 4, each of the third radiator 74 and the second radiator unit 70'superimposes a greater proportion of the inflow half portion 72' than the outflow half portion72" seen in the flow direction d. With other words, each of the third radiator 74 and thesecond radiator unit 70' covers a greater proportion of the inflow half portion 72' than theoutflow half portion 72" seen in the flow direction d. ln this manner, these radiators 74, 70'can be used to efficiently cool a vehicle system, while the impact on the cooling efficiency ofthe charge air cooler 72 is kept low. This because each of the third radiator 74 and thesecond radiator unit 70' superimposes a greater proportion of the inflow half portion 72',which has a higher temperature than the outflow half portion 72", and because a greaterproportion of the outflow half portion 72", which is cooler than the inflow half portion 72', is not faced with a radiator 74, 70' superimposing portions thereof.

The charge air cooler 72 is provided with a total surface area substantially perpendicular tothe flow direction. The wording “half portion" as used herein is intended to encompass aportion of the charge air cooler 72 which has a surface area that is half the total surface areaof the charge air cooler 72. Thus, according to the embodiments illustrated in Fig. 4, theinflow half portion 72' and the outflow half portion 72" of the charge air cooler 72 together have a surface area equal to the total surface area of the charge air cooler 72.

Since all radiators 70, 70', 74 of the second and third coolant circuits 23, 25 are arranged infront of the first radiator 46, and in front of the charge air cooler 72 seen in the flow direction,it is ensured that the second and third coolant circuits 23, 25 of the electric propulsion system9, 11, 13 is able to cool components 9, 11, 13 of the electric propulsion system 9, 11, 13, andis able to cool the condenser 17 of the waste heat recovery system 7, using coolant having alow temperature. Moreover, when the valve arrangement 8, 10 is in the second state, thesecond radiator arrangement 70, 70' can be utilized to cool the power source 5 in an efficient mannef.

According to some embodiments of the present disclosure, the second and third coolantcircuits 23, 25 may comprise at least one radiator 70, 70' between the charge air cooler 72and the first radiator 46 and at least one radiator 74 in front of the charge air cooler 72.According to such embodiments, the radiator 74 in front of the charge air cooler 72 may be aradiator 74 of the third coolant circuit 25. Due to these features, the coo|ing performance ofthe charge air cooler 72 can be improved, while it is ensured that the battery 11 can be cooled with coolant having a low temperature.

Fig. 5 illustrates a vehicle 3 according to some embodiments. The vehicle 3 comprises a powertrain 1 according to the embodiments illustrated in Fig. 1 and Fig. 2. The powertrain 1is arranged to provide motive power to the vehicle 3, via wheels 99 of the vehicle 3. As canbe seen in Fig. 5, the radiator assembly 4 of the powertrain 1 is arranged at a front area of the vehicle 3.

According to the illustrated embodiments, the vehicle 3 is a truck. However, according tofurther embodiments, the vehicle 3, as referred to herein, may be another type of manned orunmanned 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.

Fig. 6 illustrates a method 100 of controlling a coo|ing system of vehicle. The coo|ing system may be a coo|ing system 2 according to the embodiments illustrated in Fig. 1 and Fig. 2, and the vehicle may be a vehicle 3 according to the embodiments illustrated in Fig. 5. Therefore, below, simultaneous reference is made to the Figures 1, 2, 5 and 6. The method 100 is a method 100 of controlling a coo|ing system 2 of vehicle 3, wherein the coo|ing system 2 comprises a first coolant circuit 6 arranged to cool a first vehicle system 5, a second coolant circuit 23 arranged to cool a second vehicle system 9, 13, a first radiator 46, a second radiator arrangement 70, 70', and a valve arrangement 8, 10, wherein the method 100 comprises: - selectively controlling 110 the valve arrangement 8, 10 to a first state in whichthe first radiator 46 is fluidly connected the first coolant circuit 6 and the secondradiator arrangement 70, 70' is fluidly connected the second coolant circuit 23,and - selectively controlling 112 the valve arrangement 8, 10 to a second state inwhich the second radiator arrangement 70, 70' is fluidly connected the firstcoolant circuit 6 and the first radiator 46 is fluidly connected the second coolant circuit 23. 26 Moreover, as indicated in Fig. 6, the method 100 may further comprise: - determining 105 cooling demands of the first and second vehicle systems 5, 9,13, and - controlling 114 the valve arrangement 8, 10 between the first and second statesin dependence of the determined cooling demands of the first and second vehicle systems 5, 9, 13.

According to some embodiments, the valve arrangement 8, 10 comprises a first valve 8 anda second valve 10, and wherein the method 100 further comprises:- controlling 116 the first and second valves 8, 10 between the first and second states simultaneously. 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, 110, 112,114, and 116 of the method 100.

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

The control arrangement 30 may further comprise a memory unit, wherein the calculationunit may be connected to the memory unit, which may provide the calculation unit with, forexample, stored program code and/or stored data which the calculation unit may need toenable it to do calculations. The calculation unit may also be adapted to store partial or finalresults of calculations in the memory unit. The memory unit may comprise a physical deviceutilised to store data or programs, i.e., sequences of instructions, on a temporary orpermanent basis. According to some embodiments, the memory unit may compriseintegrated circuits comprising silicon-based transistors. The memory unit may comprise e.g.a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM 27 (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

The control arrangement 30 is connected to components of the powertrain 1 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 powertrain 1 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 MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection. ln the embodiments illustrated, the powertrain 1 comprises a control arrangement 30 butmight 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 30 than depicted in Fig. 1 and Fig. 2, as one skilled in the art will surely appreciate. 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 the appended claims.

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 28 presence or addition of one or more other features, elements, steps, components, functions or groups thereof.

Claims

1. CLAI l\/IS 1. A cooling system (2) for a vehicle (3), wherein the cooling system (2) comprises: - a first coolant circuit (6) arranged to cool a first vehicle system (5), - a valve arrangement (8, 10) comprising a first valve (8) and a second valve (10), - a second coolant circuit (23) arranged to cool a second vehicle system (9, 13),wherein the second vehicle system (9, 13) comprises an electric machine (9) and/orpower electronics (13), - a return line (34) fluidly connected to the first valve (8), ducting coolant from coolantportions of the electric machine (9) and the power electronics (13) to the first valve(8), - a first radiator (46), and - a second radiator arrangement (70, 70'), characteršzed in that whsseiethe ' _ valve arrangement (8, 10) inscontrollable between a first state in which the first radiator (46) is fluidly connected to the first coolant circuit (6) and the second radiator arrangement (70, 70') is fluidlyconnected to the second coolant circuit (23), and a second state in which the second radiator arrangement (70, 70') is fluidlyconnected to the first coolant circuit (6) and the first radiator (46) is fluidly connectedto the second coolant circuit (23) such that coolant in the second coolant circuit (23)flows through the return line (34) into the first valve (8) and from the first valve (8)into the first radiator (46). The cooling system (2) according to claim 1, wherein the first radiator (46) has a higher cooling capacity than the second radiator arrangement (70, 70'). The cooling system (2) according to claim 1 or 2, wherein the first vehicle system (5) comprises a power source (5) of the vehicle (3). The cooling system (2) according to any one of the preceding claims, wherein the second vehicle system (9, 13) comprises a waste heat recovery system (7). The cooling system (2) according to any one of the preceding claims, wherein thecooling system (2) comprises a control arrangement (30) configured to control the valvearrangement (8, 10) between the first and second states in dependence of cooling demands of the first and second vehicle systems (5, 9, 13). 10. 11 12. 13.

2. The cooling system (2) according to any one of the preceding claims, wherein the valvearrangement (8, 10) comprises a first valve (8) fluidly connected to the first and secondcoo|ant circuits (6, 23) and to the first radiator (46) and the second radiator arrangement(70, 70'), upstream of the first radiator (46) and the second radiator arrangement (70,70'), and a second valve (10) fluidly connected to the first and second coo|ant circuits (6,23) and to the first radiator (46) and the second radiator arrangement (70, 70'), downstream of the first radiator (46) and the second radiator arrangement (70, 70'). The cooling system (2) according to claim 6, wherein the first and second valves (8, 10) are arranged to be controlled between the first and second states simultaneously. The cooling system (2) according to any one of the preceding claims, wherein the firstradiator (46) and the second radiator arrangement (70, 70') are configured to besubjected to a flow of air having a flow direction (d), and wherein the second radiatorarrangement (70, 70') is arranged in front of the first radiator (46) seen in the flow direction (d). The cooling system (2) according to any one of the preceding claims, wherein thesecond radiator arrangement (70, 70') comprises a first radiator unit (70) and a secondradiator unit (70'). The cooling system (2) according to claim 9, wherein a coo|ant outlet (77) of the firstradiator unit (70) is fluidly connected to a coo|ant inlet (77') of the second radiator unit(70'). .The cooling system (2) according to any one of the claims -8-10, wherein the cooling system (2) further comprises a third coo|ant circuit (25) arranged to cool a third vehiclesystem (11), and wherein the third coo|ant circuit (25) comprises a third radiator (74) arranged in front of the first radiator (46) seen in the flow direction (d). The cooling system (2) according to claim 11, wherein the third vehicle system (11) comprises a battery (11). A powertrain (1) for a vehicle (3), wherein the powertrain (1) comprises a first vehiclesystem (5) and a second vehicle system (9, 13), thepowertrain (1) comprises a cooling system (2) according to any one of the preceding claims. 14. 15. 16. 17. 18. The powertrain (1) according to claim 13, wherein the powertrain (1) is arranged to operate the first vehicle system (5) and the second vehicle system (9, 13) separately. The powertrain (1) according to claim 13 orn14, wherein the powertrain (1) furthercomprises a charge air cooler (72), wherein the first radiator (46), the second radiatorarrangement (70, 70'), and the charge air cooler (72) are configured to be subjected to aflow of air having a flow direction (d), and wherein the charge air cooler (72) is arrangedin front of the first radiator (46), and the second radiator arrangement (70, 70') is arranged in front of the charge air cooler (72), seen in the flow direction (d). The powertrain (1) according to claim 15, wherein the charge air cooler (72) comprisesan inflow half portion (72') and an outflow half portion (72”), the inflow half portion (72')having a higher temperature than the outflow half portion (72”) during operation of thecharge air cooler (72), and wherein the second radiator arrangement (70, 70')superimposes a greater proportion of the inflow half portion (72') than the outflow half portion (72”) seen in the flow direction (d). The powertrain (1) according to claim 15 or 16, wherein the powertrain (1) comprises athird vehicle system (11) and a cooling system (2) according to claim 11, wherein thecharge air cooler (72) comprises an inflow half portion (72') and an outflow half portion(72”), the inflow half portion (72') having a higher temperature than the outflow halfportion (72”) during operation of the charge air cooler (72), and wherein the third radiator(74) superimposes a greater proportion of the inflow half portion (72') than the outflow half portion (72”) seen in the flow direction (d). A vehicle (3) charactærizeﬁ in that the vehicle :(5) comggršses a powertrain (1) according to any one of the claims -13 - 17. 19. A method (100) of controlling a cooling system (2) of vehicle (3), wherein the cooling system (2) comprises a first coolant circuit (6) arranged to cool a first vehicle system (5),a valve arrangement (8, 10) comprising a first valve (8) and a second valve (10), asecond coolant circuit (23) arranged to cool a second vehicle system (9, 13) comprisingan electric machine (9) and/or power electronics (13), a return line (34) fluidly connectedto the first valve (8), ducting coolant from coolant portions of the electric machine (9) andthe power electronics (13) to the first valve (8), a first radiator (46), a second radiator arrangement (70, 70'), 20. 21. 4 the method (100) Comprißeßi selectively controlling (110) the valve arrangement (8, 10) to a first state in which thefirst radiator (46) is fluidly connected to the first coolant circuit (6) and the secondradiator arrangement (70, 70') is fluidly connected to the second coolant circuit (23),and selectively controlling (112) the valve arrangement (8, 10) to a second state in whichthe second radiator arrangement (70, 70') is fluidly connected to the first coolantcircuit (6) and the first radiator (46) is fluidly connected to the second coolant circuit(23) such that coolant in the second coolant circuit (23) flows through the return line(34) into the first valve (8) and from the first valve (8) into the first radiator (46). The method (100) according to claim 19, wherein the method (100) further comprises: determining (105) cooling demands of the first and second vehicle systems (5, 9, 13), and controlling (114) the valve arrangement (8, 10) between the first and second states independence of the determined cooling demands of the first and second vehiclesystems (5, 9, 13). The method (100) according to claim 19 or 20, wherein the valve arrangement (8, 10) comprises a first valve (8) and a second valve (10), and wherein the method (100) further comprises: controlling (116) the first and second valves (8, 10) between the first and second states simultaneously.