WO2019039990A1

WO2019039990A1 - A cooling arrangement for a hybrid vehicle comprising an electric drive unit, a combustion engine and a whr system

Info

Publication number: WO2019039990A1
Application number: PCT/SE2018/050838
Authority: WO
Inventors: Zoltan Kardos; Ola Hall; Tomas Alsterdal; Markus MUSTONEN
Original assignee: Scania Cv Ab
Priority date: 2017-08-25
Filing date: 2018-08-20
Publication date: 2019-02-28
Also published as: SE1751024A1; SE541209C2; DE112018003581B4; DE112018003581T5

Abstract

The present invention relates to a cooling arrangement for a hybrid vehicle (1) comprising an electric drive unit (2), a combustion engine (3) and a WHR system (4), wherein the cooling arrangement comprises a cooler package (5) arranged in an air flow passage (6) of the hybrid vehicle (1).The cooler package (5) comprises a first radiator (r1) which is primarily used to cool coolant for cooling of an energy storage (2b) of the electric drive unit (2), a second radiator (r2) which is primarily used to cool coolant for cooling of cooling power electronics (2c) of the electric drive unit (2), a third radiator (r3) which is primarily used to cool coolant for cooling of a condenser (4a) of the WHR system (4) and a fourth radiator (r4) which is used to cool coolant for cooling of the combustion engine (3). The first radiator (r1) and the second radiator (r2) are arranged in positions upstream of the third radiator (r3) and the fourth radiator (r4) in view of the intended flow direction of a cooling air flow (7) through the air flow passage (6).

Description

A cooling arrangement for a hybrid vehicle comprising an electric drive unit, a combustion engine and a WHR system

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention relates to a cooling arrangement for a hybrid vehicle comprising an electric drive unit, a combustion engine and a WHR system according to the preamble of claim 1. Hybrid vehicles may be powered by an electric drive unit and a combustion engine. The electric drive unit may comprise an electric machine which alternately works as motor and generator, an electrical energy storage storing electrical energy and power electronics controlling the flow of electrical energy between the electrical energy storage and the electric machine. The electric machine, the electrical energy storage and the power electronics are heated during operation and they need to be cooled. The electrical energy storage is designed to operate within a specific temperature range, which may be within the temperature range of 20-40°C. The power electronics can usually withstand a temperature up to about 60-70 °C. The combustion engine may have an optimal efficiency within a temperature range of 90- 110°C. A cooling system for cooling of the electrical energy storage and the power electronics needs to provide coolant at two different temperature levels for providing a sufficient cooling of the electrical energy storage and the power electronics se components. A conventional such cooling system comprises two radiators which are arranged on a longitudinal frame on one side of the vehicle.

In order to reduce the energy consumption of a motor vehicle powered by a combustion engine, it is possible to use a WHR system (Waste Heat Recovery System) which recovers waste thermal energy and convert it to mechanical energy or electrical energy. The WHR system may recover heat energy from the exhaust gases of the combustion engine. In order to achieve a high thermal efficiency of a WHR system, the working medium has to be cooled in a condenser to a condensation temperature as low as possible and substantially without subcooling. In case ethanol is used as working medium, an optimal condensation temperature is about 70 °C. It is known to cool the working medium in the condenser by coolant circulating in a cooling system which also cools the combustion engine. Such a conventional cooling system comprises at least two radiators arranged at a front portion of the vehicle.

Thus, a hybrid vehicle provided with a WHR system comprises components which are to be cooled to a plurality of different temperature levels. To use two separate cooling systems for cooling of the hybrid components and the WHR system having the radiators arranged at different positions in the vehicle requires a lot of space in a vehicle.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a cooling arrangement for a hybrid vehicle provided with a WHR system, which is able to cool the including components to required temperature levels at the same time as it requires a relatively small space in the vehicle.

The above mentioned object is achieved by the cooling arrangement according to claim 1. The cooling arrangement comprises a cooler package comprising four radiators. A first radiator is primarily used to cool coolant for cooling of the energy storage, a second radiator is primarily used to cool coolant for cooling of the power electronics, a third radiator is primarily used to cool coolant for cooling of the working medium in a condenser of the WHR system and a fourth radiator is primarily used to cool coolant for cooling of the combustion engine. All radiators are arranged in a common air flow passage in the vehicle. Since the first radiator and the second radiator are arranged in positions upstream of the third radiator and the fourth radiator it is possible to cool the energy storage and the power electronics with coolant of a lower temperature than the coolant cooling the condenser and the combustion engine. In view of the fact that all radiators are arranged in a common cooler package in a common air flow passage, the radiators require a relatively small space. The cooler package is preferably arranged in a common air flow passage at a front portion of the vehicle. The first radiator and the second radiator are preferably arranged in a position in which they are cooled by air of ambient temperature.

According to an embodiment of the invention, the first radiator and the second radiator are arranged in a common plane roughly perpendicular to the intended flow direction of the cooling air flow through the flow passage. "Rougly perpendicular" may be interpreted as "substantially perpendicular". The common plane may e.g. be arranged within the range of 80-100 degrees relatively the intended flow direction. In this position the first radiator and the second radiator may form a relatively thin upstream layer of the cooler package. Consequently, the first radiator and the second radiator require are relatively small space in the cooler package. The third radiator and the fourth radiator may be arranged in a common plane roughly perpendicular to the intended flow direction of the cooling air flow through the flow passage. The third radiator and the fourth radiator may form a downstream layer of the cooler package. Thus, the third radiator and the fourth radiator also require are relatively small space in the cooler package.

According to an embodiment of the invention, the first radiator is arranged in a position in relation to the third radiator such at least a part of the cooling air flow which flows through the first radiator also flows through the third radiator. Such a positioning of the first radiator and the third radiator results in that the third radiator is cooled by an air flow of a higher temperature than the first radiator. However, the cooling requirement of the energy storage is greatest during operating conditions when the hybrid vehicle is powered by the electric drive unit and the cooling requirement of the condenser is greatest when the hybrid vehicle is powered by the combustion engine. Consequently, a high cooling requirement of the first radiator does not coincide with a high cooling requirement of the third radiator. In view of this fact, it is substantially always possible to cool the coolant in the third radiator by air of a relatively low temperature during operating conditions when there is a high cooling requirement of the working medium in the condenser. According to an embodiment of the invention, the cooling arrangement comprises at least one electric radiator fan arranged in a position such that it is able to provide a forced cooling air flow through the first radiator and the third radiator. By means of such an electric radiator fan, it is possible to adjust the air flow through the first radiator and the third radiator and thus the cooling effect of the coolant in the first radiator and the third radiator.

According to an embodiment of the invention, the cooler package comprises a charge air cooler. In case the combustion engine is supercharged, it is suitable to arrange the charge air cooler in the cooler package. The charge air cooler may be arranged in a position downstream of the second radiator such at least a part of the air which flows through the second radiator also flows through the charge air cooler. In this case, the charged air is cooled by air of a higher temperature than the coolant in the second radiator. However, the cooling requirement of the power electronics is greatest during operating conditions when the hybrid vehicle is powered by the electric drive unit and the cooling requirement of the charge air is greatest when the hybrid vehicle is powered by the combustion engine. Consequently, a high cooling requirement of the coolant in the second radiator does not coincide with a high cooling requirement of the air in the charge air cooler. In view of this fact, it is substantially always possible to cool the charge air in the charge air cooler by air of a relatively low temperature during operating conditions when there is a high cooling requirement of the charge air.

According to an embodiment of the invention, the at least one electric radiator fan and the charge air cooler are arranged in a common plane roughly perpendicular to the intended flow direction of the cooling air flow through the flow passage. The electric radiator fan and the charge air cooler may form an intermediate layer of the cooler package arranged in a position downstream of the first radiator and the second radiator and in a position upstream of the third radiator and the fourth radiator. Such an arrangement of the electric radiator fan and the charge air cooler make that they require are relatively small space in the cooler package. According to an embodiment of the invention, the cooling arrangement comprises a mechanical radiator fan driven by the combustion engine which is configured to force cooling air flow through the radiators when the combustion engine is in operation. The mechanical radiator fan ensures that the cooler package receives a sufficient cooling air flow during operating conditions when the combustion engine is running.

According to an embodiment of the invention, the cooling arrangement comprises flow path members which are able to create a first primary coolant flow path in which the energy storage is cooled by coolant from the first radiator, a second primary coolant flow path in which the power electronics are cooled by coolant from the second radiator and a third primary coolant flow path in which the condenser is cooled by coolant from the third radiator. Such primary coolant flow path members may comprise two way valves or three way valves directing the coolant flow between the radiators and the respective components to be cooled.

According to an embodiment of the invention, said coolant flow path members are able to stop the coolant flow between the first radiator and the energy storage during operating condition when it is not possible to cool the coolant in the first radiator to a temperature low enough for cooling the energy storage. When ambient temperature air is too high, it is not possible to cool the energy storage by coolant from the first radiator. In this case, the energy storage may be cooled by a separate coolant circuit in which the coolant is cooled by a refrigeration system.

According to an embodiment of the invention, said coolant flow path members are able to provide an alternative coolant flow path making it possible to cool the power electronics or the condenser by coolant from the first radiator when the coolant flow between the first radiator and the energy storage is stopped. At high ambient temperatures, when it is not possible to cool the coolant in the first radiator to a temperature low enough for cooling the energy storage, it is a great opportunity to use the first radiator for increasing the cooling of the power electronics or the condenser. In this case, the power electronics may be cooled by coolant circulating through the first radiator and the second radiator in parallel or in series. Alternatively, the condenser is cooled by coolant circulating through the first radiator and the third radiator in parallel or in series.

According to an embodiment of the invention, said coolant flow path members are able to stop the coolant flow through the second radiator during operating condition when a cooler arranged in a position downstream of the second radiator requires an increased cooling. When the coolant flow through the second radiator ceases, the downstream positioned cooler will be cold by an air flow of a lower temperature. This measure increases the cooling capacity in the downstream positioned cooler. The downstream positioned cooler may be the charge air cooler or the fourth radiator which cools the combustion engine.

According to an embodiment of the invention, said coolant flow path members are able to provide an alternative coolant flow path making it possible to cool the power electronics by coolant from the third radiator when it is no cooling requirement of the condenser at the same time as it is cooling requirement of the power electronics. When there is no need to cool the condenser, it is a great opportunity to use the third radiator to provide an increased cooling of the power electronics. In this case, the power electronics may be cooled by coolant circulating through the second radiator and the third radiator in parallel or in series.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following a preferred embodiment of the invention is described, as an example, with reference to the attached drawings, in which:

Fig. 1 shows a cooler package of a cooling arrangement according to the

invention,

Fig 2 shows an exploded view of the cooler package and

Fig 3 shows an embodiment of individual cooling circuits of the cooling

arrangement. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE

INVENTION

Fig. 1 shows a front portion of a schematically indicated hybrid vehicle 1. The hybrid vehicle 1 is powered by an electric drive unit 2, a combustion engine 3 and a WHR system 4. The electric drive unit 2 comprises an electric machine 2a which alternately works as motor and generator, an electrical energy storage 2b storing electrical energy and power electronics 2c controlling the flow of electrical energy between the electrical energy storage 2b and the electric machine 2a. The electrical energy storage 2a are designed to operate within a relatively low temperature range of about 20-40°C. The power electronics can usually withstand a temperature up to about 60-70°C. The combustion engine 3, which may be a supercharged diesel engine, may have an optimal efficiency within a temperature range of 90- 110°C. The WHR system 4 may have a conventional design comprising a pump which pressurizes and circulates a working medium in the system, an evaporator in which the working medium is heated to an evaporation temperature by a heat sources. The heat source may be the exhaust gases from the combustion engine 3. The pressurized and heated gaseous working medium is expanded in an expander such that mechanical energy is generates which can be used to power the hybrid vehicle 1 or apparatuses on the hybrid vehicle 1. Alternatively, the expander is connected to a generator generating electrical energy. The working medium leaving the expander is received in a condenser 4a. The working medium is cooled in the condenser 4a to a temperature at which it condenses. In order to achieve a high thermal efficiency of a WHR system, the working medium has to be cooled to a condensation temperature as low as possible and substantially without subcooling. In case the working medium is ethanol, it is suitable to provide a condensation temperature of about 70°C in the condenser 4a. Thus, in order to provide a sufficient cooling of the electrical energy storage 2b, the power electronics 2c, the combustion engine 3 and the condenser 4a they are to be cooled by coolant of different temperatures. A cooling arrangement for cooling of the electrical energy storage 2b, the power electronics 2c, the combustion engine 3 and the condenser 4a comprises a cooler package 5 arranged in an air flow passage 6 at a front portion of the hybrid vehicle 1. During operation of the vehicle 1, a cooling air flow 7 flows through the air flow passage 6 and cools the cooler package 5. The cooler package 5 comprises a first radiator π and a second radiator r₂ which forms a first layer of the cooler package 5 in a common first plane Ai roughly perpendicular to the intended flow direction of the cooling air flow 7 through the flow passage 6. The cooler package 5 comprises a number of electric radiator fans 8 arranged in a position downstream of the first radiator n. A charge air cooler 9 is arranged in a position downstream of the second radiator r₂ in the flow passage 6. The electric radiator fans 8 and the charge air cooler 9 form a second layer of the cooler package in a common second plane A₂ roughly perpendicular to the intended flow direction of the cooling air flow 7 through the flow passage 6. The cooler package 5 comprises a third radiator r₃ and a fourth radiator r₄ forming a third layer in a common third plane A₃ roughly perpendicular to the intended flow direction of the cooling air flow 7 through the flow passage 6. The third plane A₃ is arranged in a position downstream of the second plane A₂ in view of the intended direction of the cooling air flow 7 through the flow channel 6. The cooling air flow 7 through the flow passage 6 is generated by ram air, the electric radiator fans 8 and a mechanical radiator fan 10. A fan shroud 11 defines an end portion of the coolant flow path 6.

Usually, a large air flow through the air flow passage 6 passage reduces the

aerodynamic of the vehicle 1 and increases the energy consumption of a vehicle. In order to prevent an unnecessarily large air flow through the air flow passage 6 during operating conditions when there is a low cooling requirements of the cooler package 5, a first jalousie device ji is arranged in a position upstream of the first radiator n and a second jalousie device j₂ is arranged in a position upstream of the second radiator r₂. In case, there is a high cooling requirement of the coolant in the second radiator r₂ or in the fourth radiator r₄, at the same time as there is low cooling requirements of the coolant in the first radiator π and the third radiator r₃, the first jalousie device ji is moved to the closed position. In case, there is a high cooling requirement of the coolant in the first radiator π or the third radiator r₃, at the same time as there low cooling requirements of the coolant in the second radiator r₂ and in the fourth radiator r₄, the second jalousie device j₂ is moved to the closed position. Alternatively, the first jalousie device ji may be arranged in a position between the first radiator n and the third radiator r₃. In this case, the first jalousie device ji may replaces the electric radiator fans 8.

Fig. 2 shows an exploded view of the cooler package 5. The first radiator n is primarily used to cool coolant directed, via a schematically indicated first coolant circuit ci, to the energy storage 2b. The second radiator r₂ is primarily used to cool coolant directed, via a schematically indicated second coolant circuit c₂, to the power electronics 2c. The third radiator r₃ is primarily used to cool coolant directed, via a schematically indicated third coolant circuit c₃, to the condenser 4a. The fourth radiator r₄ is used to cool coolant directed, via a schematically indicated fourth coolant circuit c₄, to the combustion engine 3. The fourth cooling circuit c₄ may have a conventional design comprising a not indicated coolant pump which circulates the coolant in the fourth coolant circuit c₄, a radiator bypass line and a thermostat directing the coolant to the radiator bypass line or the fourth radiator r₄ in view of the temperature of the coolant.

Fig 3 shows an embodiment of the first coolant circuit ci, the second coolant circuit c₂ and the third coolant circuit c₃. The first cooling circuit ci comprises a first coolant pump pi used to circulate coolant through the first coolant circuit ci and the energy storage 2b. The first circuit ci is connectable to the first radiator π by means of a first three way valve vi which is arranged at an inlet of the first radiator π and a second three way valve v₂ which is arranged at an outlet of the first radiator n.The second cooling circuit c₂ comprises a second coolant pump p₂ used to circulate coolant through the second circuit c₂ and the power electronics 2c. The second circuit c₂ is connectable to the second radiator r₂ by means of a third three way valve v₃ which is arranged at an inlet of the second radiator r₂ and a fourth three way valve v₄ which is arranged at an outlet of the second radiator r₂. The third cooling circuit c₃ comprises a third coolant pump p₃ used to circulate coolant through the third circuit c₃ and the condenser 4a. The third circuit c₃ is connectable to the third radiator r₃ by means of a fifth three way valve vs which is arranged at an inlet of the third radiator r₃ and a sixth three way valve v₆ which is arranged at an outlet of the third radiator r₃. The cooling arrangement comprises a first connection line li making it possible to direct coolant from the second coolant circuit c₂ to the first radiator n and a second connection line 1₂ making it possible to return the coolant from the first radiator n to the second coolant circuit c₂. The existence of the first connection line li and the second connection line 1₂ make it possible to cool the coolant in the second coolant circuit c₂ in the first radiator n. The cooling arrangement comprises a third connection line 1₃ making it possible to direct coolant from the second coolant circuit c₂ to the third radiator r₃ and a fourth connection line 1₄ making it possible to return coolant from the third radiator r₃ to the second coolant circuit c₂. The existence of the third connection line 1₃ and the fourth connection line 1₄ make it possible to cool the coolant in the second coolant circuit c₂ in the third radiator r₃.

A control unit 12 controls the above mentioned valves vi-6 and the pumps pi_₃ in the respective circuits ci_₃ by means of information 13 about relevant operating parameters. Said operating parameters may include the ambient air temperature and the

temperature of the energy storage 2b. The control unit 12 may receive substantially continuously information from temperature sensors about said temperatures. However, it is only possible to cool the energy storage 2b by coolant from the first radiator n in case the coolant is cooled to a temperature in the first radiator π which is lower than the temperature of the energy storage 2b. The control unit 12 determines if ambient air temperature is low enough to cool the coolant in the first radiator π to a temperature which is lower than the temperature of the energy storage 2b.

If this is the case, the control unit 12 positions the first three way valve vi such that it directs coolant from the energy storage 2b in a first flow direction via to the first radiator π and the second three way valve v₂ such that it directs the coolant from the first radiator π in a first flow direction v_2a to the energy storage 2b. Said positioning of the first three way valve vi and the second three way vale v₂ creates a first primary coolant flow path in which the coolant is cooled in the first radiator π before it cools the energy storage 2b. On the other hand, if ambient air temperature is not low enough to cool the coolant in the first radiator π to a temperature lower than the temperature of the energy storage 2b, the control unit 12 shuts off the first pump pi and controls the three way valves vi, v₂ such that the coolant flow between the energy storage 2b and the first radiator π is stopped. The control unit 12 starts a not shown refrigeration system which cools coolant in a separate not shown coolant circuit. The coolant in said separate circuit is used to cool the energy storage 2b. The control unit 12 may receive information 13 about the temperature of the power electronics 2c. In case ambient air temperature is too high for cooling the energy storage 2b, it is likely that also the power electronics 2c requires an increased cooling. In such a case, the control unit 12 positions the third three way valve v₃ such that it directs a part of the coolant flow from the power electronics 2c in a first flow direction v_3a towards the second radiator r₂ and a remaining part of said coolant flow in a second flow direction v¾ to the first connection line li. The control unit 12 positions the first three way valve vi such that it directs the coolant flow in the first connection line li in a second flow direction vib towards the first radiator n. Furthermore, the second three way valve v₂ is positioned by the control unit 12 such that the coolant leaving the first radiator π is directed in a second flow direction v₂b to the second connection line 1₂ and back to the second coolant circuit c₂ in a position downstream of the fourth three way valve v₄. The fourth three way valve v₄ is positioned such that it directs the coolant leaving the second radiator r₂ in a first flow direction v_4a toward the second pump p₂ and the power electronics 2c.

Consequently, during operating conditions when the first radiator π is not used for cooling the energy storage 2b, it is possible to circulate the coolant in the second coolant circuit c₂ by the second coolant pump p₂ via an alternative coolant flow path in which the coolant flows through the first radiator π and the second radiator r₂ in parallel before the coolant cools the power electronics 2c. Alternatively, the second connection line 1₂ may direct the coolant leaving the first radiator n to the second circuit c₂ in a position upstream of the second radiator r₂. In such a case, it is possible to cool the coolant in the first radiator π and the second radiator r₂ in series before it cools the power electronics 2c.

The control unit 12 may also receive information 13 about the temperatures of the charge air leaving the charge air cooler 9 and the temperature of the combustion engine 3. In case the temperatures of the charge air and the combustion engine 3 are lower than a maximum acceptable temperature, the control unit 12 maintains the regular cooling of the coolant in the second radiator r₂ and thus the cooling of the power electronics 2c. On the other hand, in case the temperature of the charge air or the temperature of the combustion engine 3 is higher than a maximum acceptable temperature, the control unit 12 determines that the charge air or the combustion engine 3 require an increased cooling. In such a case, the control unit 12 starts the refrigeration system which takes over the cooling of the energy storage 2b.

Furthermore, the control unit 12 positions the third three way valve v₃ such that it directs the entire coolant flow from the power electronics 2c in the second flow direction v¾ to the first connection line li and via the first three way valve vi to the first radiator n. The control unit 12 positions the second three way valve v₂ such that the coolant leaving the first radiator n is directed in the second flow direction v2b to the second connection line 1₂ and back to the second circuit c₂. In this case, the coolant in the second circuit c₂ is only cooled in the first radiator n. Since there is no coolant to be cooled in the second radiator r₂, the cooling air flow 7 has a lower temperature when it passes through the charge air cooler 9 and the fourth radiator r₄. The lower temperature of the cooling air flow 7 results in an increased cooling of the charge air in the charge air cooler 9 and the coolant in the fourth radiator r₄. This measure will probably reduce the temperature of the charge air and the temperature of the combustion engine 3 to an acceptable level.

The control unit 12 may also receive information 13 about the cooling requirement of the WHR system 4. During operating conditions when there is a cooling requirement of the working medium in the condenser 4a, the control unit 12 positions the fifth three way valve vs such that coolant from the condenser 4a directs coolant in a first flow direction vsa to the third radiator r₃. The coolant leaving the third radiator r₃ is directed in a first flow direction v₆a by the sixth three way valve v₆ towards the third coolant pump p3 and the condenser 4a.In this case, the third pump p3 circulates coolant through a primarily flow path between the third radiator r₃ and the condenser 4a. On the other hand, during operating conditions when there is no cooling requirement of the working medium in the condenser 4a, the control unit 12 receives information about the temperature of the power electronics 2c. In case the power electronics 2c requires an increased cooling, the control unit 12 shuts off the third pump p₃ such that the coolant circulation in the third coolant circuit c₃ ceases. The control unit 12 positions the fourth three way valve v₄ such that the coolant leaving the second radiator r₂ is directed in a second flow direction v₄b to the third connection line 1₃. The control unit 12 positions the fifth three way valve vs such that the coolant in the third connection line 1₃ is directed in a second flow direction vsb to the third radiator r₃. The control unit 12 positions the sixth three way valve v₆ such that the coolant leaving the third radiator r₃ is directed in a second flow direction v₆b to the fourth connection line 1₄ and back to the second coolant circuit c₂. Consequently, during operating conditions when there is no cooling requirement of the condenser 4a, it is possible to circulate the coolant in the second circuit c₂, via an alternative coolant flow path, from the second coolant circuit c₂ through the second radiator r₂ and the third radiator r₃ in series and provide an increased cooling of the power electronics 2c.

The invention is not restricted to the described embodiment but may be varied freely within the scope of the claims. It is, for example, possible to use other kinds of valves and connecting lines for creating primary coolant flow paths and alternative coolant flow paths between the respective radiators and the components to be cooled. The coolant circuits ci_₄ may be used to cool more objects than the above indicated. The second circuit c₂ may, for example, also be used to cool the electric machine 2a.

Claims

1. A cooling arrangement for a hybrid vehicle (1) comprising an electric drive unit (2), a combustion engine (3) and a WHR system (4), wherein the cooling arrangement comprises a cooler package (5) arranged in an air flow passage (6) of the hybrid vehicle (1), characterized in that the cooler package (5) comprises a first radiator (n) which is primarily used to cool coolant for cooling of an energy storage (2b) of the electric drive unit (2), a second radiator (r₂) which is primarily used to cool coolant for cooling of power electronics (2c) of the electric drive unit (2), a third radiator (r₃) which is primarily used to cool coolant for cooling of a condenser (4a) of the WHR system (4) and a fourth radiator (r₄) which is used to cool coolant for cooling of the combustion engine (3) and that the first radiator (n) and the second radiator (r₂) are arranged in positions upstream of the third radiator (r₃) and the fourth radiator (r₄) in view of the intended flow direction of an cooling air flow (7) through the air flow passage (6).

2. A cooling arrangement according to claim 1, characterized in that the first radiator (n) and the second radiator (r₂) are arranged in a common plane (Ai) roughly perpendicular to the intended flow direction of the cooling air flow (7) through the flow passage (6).

3. A cooling arrangement according to claim 1 or 2, characterized in that the third radiator (r₃) and the fourth radiator (r₄) are arranged in a common plane (A₃) roughly perpendicular to the intended flow direction of the cooling air flow (7) through the flow passage (6).

4. A cooling arrangement according to any one of the preceding claims, characterized in that the third radiator (r₃) is arranged in a position downstream of the first radiator (n) such at least a part of the cooling air flow (7) which flows through the first radiator (ri) also flows through the third radiator (r₃).

5. A cooling arrangement according to claim 4, characterized in that the cooling arrangement comprises at least one electric radiator fan (8) arranged in a position in which it is able to provide a forced cooling air flow (7) through the first radiator (n) and the third radiator (r₃).

6. A cooling arrangement according to any one of the preceding claims, characterized in that the cooler package (5) comprises a charge air cooler (9).

7. A cooling arrangement according to claim 6, characterized in that the charge air cooler (9) is arranged in a position downstream of the fourth radiator (r₄) such at least a part of the cooling air flow (7) which flows through the charge air cooler (9) also flows through the fourth radiator (r₄).

8. A cooling arrangement according to claim 5 and 7, characterized in that the at least one electric radiator fan (8) and the charge air cooler (9) are arranged in a common plane (A₂) roughly perpendicular to the intended flow direction of the cooling air flow (7) through the flow passage (6).

9. A cooling arrangement according to any one of the preceding claims, characterized in that the cooling arrangement comprises a mechanical radiator fan (10) driven by the combustion engine (2) which is configured to force cooling air flow (7) through the radiators (n - r₄) when the combustion engine (3) is in operation.

10. A cooling arrangement according to any one of the preceding claims,

characterized in that the cooling arrangement comprises flow path members (vi-v₆, li- 1₄) which are able to create a first primary coolant flow path in which the energy storage (2b) is cooled by coolant from the first radiator (n), a second primary coolant flow path in which the power electronics (2c) are cooled by coolant from the second radiator (r₂) and a third primary coolant flow path in which the condenser (4a) is cooled by coolant from the third radiator (r₃).

11. A cooling arrangement according to claim 10, characterized in that said coolant flow path members (vi-v₆, li-U) are able to stop the coolant flow between the first radiator (n) and the energy storage (2b) during operating condition when it is not possible to cool the coolant in the first radiator (n) to a temperature low enough for cooling the energy storage (2b).

12. A cooling arrangement according to claim 11, characterized in that said coolant flow path members (vi-v₆, li-U) are able to provide an alternative coolant flow path making it possible to cool the power electronics (2c) or the condenser (4a) by coolant from the first radiator (n) when the coolant flow between the first radiator (n) and the energy storage (2b) is stopped.

13. A cooling arrangement according to any one of the preceding claims 10-12, characterized in that said coolant flow path members (vi-v₆, li-U) are able to stop the coolant flow through the second radiator (r₂) during operating condition when a cooler (9, r₄) arranged in a position downstream of the second radiator (r₂) requires an increased cooling .

14. A cooling arrangement according to any one of the preceding claims 10-13, characterized in that said coolant flow path members (vi-v₆, li-U) are able to provide an alternative coolant flow path making it possible to cool the power electronics (2c) by coolant from the third radiator (r₃) when it is no cooling requirement of the condenser (4a) at the same time as it is cooling requirement of the power electronics (2c).

15. A vehicle (1), characterized in that it comprises a cooling arrangement according to any one of the preceding claims 10-14.