Cooling system and method for increasing cooling performance for a drive unit

Abstract

Cooling system (10, 20) for increasing the cooling capacity of a drive unit with a cooling circuit (11, 12), namely a high-temperature cooling circuit, which includes a coolant flowing through the cooling circuit (11, 12), a high-temperature cooler (18), at least one intermediate circuit (14) with an intermediate medium flowing through the respective intermediate circuit (14), further in the intermediate circuit (14) at least one chiller (15) configured to transfer heat from the cooling circuit (11, 12) to the at least one intermediate medium, and further in the intermediate circuit (14) at least one indirect condenser (13), wherein the cooling system (10, 20) includes a circuit (11, 12; 21, 22) with a medium flowing through the circuit, and the at least one indirect condenser (13) is arranged in the circuit (11, 12; 21, 22) and is configured to transfer heat from the respective intermediate medium to the medium within the circulatory system (11, 12;21, 22) to transfer, characterized in that the cooling circuit (11, 12) comprises a branch (11) coming from a fuel cell system and a branch (12) going to the fuel cell system, wherein the indirect condenser (13) is integrated into a feed (19) of the high-temperature cooler (18) on the incoming branch (11), and wherein the chiller (15) is integrated into the going branch (12).

Description

[0001] The invention relates to a cooling system for increasing the cooling performance of a drive unit with a cooling circuit, in particular a high-temperature cooling circuit with a high-temperature cooler.

[0002] The cooling of drive units is subject to increased demands because their operation generates high heat losses due to an efficiency of approximately 50%, most of which are dissipated to a coolant. Furthermore, a maximum coolant temperature must not be exceeded during the operation of such drive units, resulting in small temperature differences between the coolant temperature and the ambient temperature at the coolant radiator.

[0003] Document DE 10 2014 109 524 A1 discloses an air conditioning system control method for a vehicle. This discloses a multi-circuit cooling circuit of a fuel cell vehicle, which absorbs heat from a drive component and transfers it to a second circuit with an evaporator by means of a liquid.

[0004] Document WO 2004 033 859 A1 discloses a method for energy recovery in which a fuel cell of a vehicle transfers heat via an intermediate circuit to another fluid circuit with a condenser.

[0005] Document DE 10 2014 111 971 A1 discloses an air conditioning system for a vehicle which includes a refrigeration circuit having several heat exchangers with which heat from the refrigeration circuit is transferred to a coolant and then released by the coolant to an environment via further heat exchangers.

[0006] DE 11 2014 003 502 T5 describes a vehicle management system that combines a refrigerant circuit with a cooling circuit to increase efficiency using multi-way valves.

[0007] DE 10 2016 006 682 A1 describes a method for operating an air conditioning system of an electric or hybrid vehicle, as well as an air conditioning system for carrying out the method. A thermal energy storage system is used to make heat available at specific times, thereby increasing the efficiency of the air conditioning system.

[0008] German patent DE 11 2014 001 830 T5 describes a thermal management system for a vehicle. The aim is to improve the structure of the vehicle's thermal management system, thereby facilitating switching between different devices.

[0009] DE 10 2011 082 584 A1 describes a device for temperature control of a plurality of components of a vehicle as well as a vehicle system.

[0010] The disadvantages of known methods and devices are that their cooling capacity is insufficient. Furthermore, they require the placement of an additional heat exchanger in the front of the vehicle. This introduces an additional hazard to the front of the vehicle, as flammable refrigerants must be routed through a crash zone there.

[0011] Therefore, the object of the present invention is to provide a cooling system that improves the cooling performance of a drive unit or a fuel cell system and increases the safety of the cooling system.

[0012] This problem is solved by a cooling system having the features of claim 1, a use having the features of claim 6, and a fuel cell vehicle having the features of claim 8.

[0013] The present invention relates to a cooling system for increasing the cooling capacity of a drive unit, comprising a cooling circuit, in particular a high-temperature cooling circuit, a coolant circulating in the cooling circuit, and a high-temperature radiator. The cooling system is preferably arranged in the area of ​​the drive unit or a fuel cell system. The drive unit can be located in the front or rear of a fuel cell vehicle.

[0014] According to the invention, the cooling system comprises at least one intermediate circuit with an intermediate medium flowing through each intermediate circuit and, further within the intermediate circuit, at least one chiller configured to transfer heat from the cooling circuit to the intermediate medium and thus provide cooling capacity. The chiller is configured as an indirect evaporator, preferably designed to cool the coolant. The heat extracted from the coolant by the chiller is supplied to an intermediate medium within the intermediate circuit. The cooling system further comprises at least one indirect condenser within the intermediate circuit, configured to transfer heat from the intermediate medium to a medium within a circuit encompassed by the cooling system.In the respective indirect condenser, heat transfer takes place from the respective intermediate medium to the respective medium, in contrast to heat transfer to ambient air known from the prior art.

[0015] The chiller extracts additional heat from the coolant as it passes through the high-temperature radiator in the cooling circuit, thereby increasing the cooling capacity of the cooling system. Furthermore, the required amount of coolant can be reduced, and an accumulator or reservoir can be eliminated. This simplifies the complex design of the cooling system, enabling a more compact construction. Additionally, there is no need to place an extra heat exchanger in the front of the vehicle. This eliminates the need to create an additional hazard in the front of the vehicle and avoids routing a potentially flammable refrigerant through a crash zone in the front or rear of the fuel cell vehicle.

[0016] In a preferred embodiment of the invention, the indirect condenser and the chiller are arranged in the intermediate circuit. The intermediate circuit preferably comprises the indirect condenser, the chiller, an expansion valve, and a compressor. The intermediate circuit with the indirect condenser and the chiller, which provides the cooling capacity, makes it possible to integrate the indirect condenser into the cooling system and to increase the cooling capacity of the cooling circuit, particularly the high-temperature cooling circuit. Optionally, the cooling system can include at least one further intermediate circuit.

[0017] In one embodiment of the invention, the indirect condenser is arranged in the inlet of the high-temperature cooler. Placing the indirect condenser in the inlet of the high-temperature cooler enables a particularly compact design of the cooling system while simultaneously increasing cooling capacity. Furthermore, the intermediate circuit and the cooling circuit are connected by placing the indirect condenser in the inlet of the high-temperature cooler.

[0018] In a further development of the invention, the intermediate medium is designed to be coolable. As described, the indirect condenser is designed to extract heat from the intermediate medium and transfer it to another medium. Through indirect condensation, the heat of condensation from the intermediate circuit is not released directly to the ambient air, but first to a medium within the circuit. This increases the cooling capacity of the drive unit's cooling system and simultaneously improves operational reliability. Furthermore, an accumulator can be omitted. This reduces the amount of flammable liquids in the cooling system. The ability to cool the intermediate medium further enhances the cooling capacity of the cooling system. Optionally, the intermediate medium can be designed to be cooled multiple times.

[0019] The intermediate medium preferably comprises a refrigerant. The design of the intermediate medium is preferably adaptable. Depending on the application, the intermediate medium can be formed by a refrigerant which, for example, is derived from a class of substances formed from fluorinated hydrogen halides, in particular freons.

[0020] If the indirect condenser is located in the inlet of the high-temperature cooler, the medium to which the indirect condenser transfers heat is the coolant of the cooling circuit. Since the indirect condenser is located in the inlet of the high-temperature cooler, the heat supplied to the coolant at this point can be immediately dissipated again within the high-temperature cooler, e.g., to the ambient air.

[0021] In a further cooling system – not covered by the invention – a low-temperature cooling circuit is arranged at the indirect condenser. This low-temperature cooling circuit is designed to absorb heat from the indirect condenser. The low-temperature cooling circuit can increase the cooling capacity of the cooling system by at least partially absorbing the heat from the indirect condenser and dissipating it, for example, to the ambient air.

[0022] The present invention also relates to the use of the cooling system for carrying out a method for increasing the cooling performance of a drive unit with a cooling circuit, in particular a high-temperature cooling circuit, comprising a cooling system as described above.

[0023] In the method, which includes a coolant circulating in the cooling circuit, a high-temperature cooler, at least one intermediate circuit with a respective intermediate medium circulating in the respective intermediate circuit, further in the intermediate circuit at least one chiller designed to transfer heat from the cooling circuit to the at least one intermediate medium, and further in the intermediate circuit at least one indirect condenser, the at least one indirect condenser is arranged in a circuit, wherein the circuit has a medium circulating in the circuit, and heat is transferred from the respective intermediate medium to the medium by the indirect condenser.

[0024] The intermediate circuit preferably also includes a compressor and an expansion valve. As the intermediate medium passes through the intermediate circuit with the indirect condenser and the chiller, heat is released from the intermediate medium in the indirect condenser and absorbed from the intermediate medium in the chiller. The intermediate circuit includes the indirect condenser, a compressor, a chiller, and an expansion valve. The chiller cools the refrigerant and thus provides the cooling capacity. The intermediate circuit makes it possible to integrate indirect condensation into the cooling system and to increase and improve the cooling capacity of the cooling circuit, especially the high-temperature cooling circuit.

[0025] In a further development of the process, the indirect condenser is integrated into the upstream section of the high-temperature cooling circuit. At this point, the indirect condenser transfers heat from the intermediate circuit to the coolant. The integration of the indirect condenser into the upstream section of the high-temperature cooling circuit allows for a particularly compact design of the cooling system while simultaneously increasing cooling capacity. Advantageously, the chiller is positioned downstream of the high-temperature cooler in the cooling circuit, contributing to further cooling of the coolant, which has already been cooled in the high-temperature cooler.

[0026] In an embodiment of the method – not covered by the invention – heat is transferred from the intermediate circuit to a medium flowing through the low-temperature cooling circuit by means of at least one indirect condenser arranged in a low-temperature cooling circuit. The low-temperature cooling circuit can then dissipate this heat via a low-temperature cooler. This increases the cooling capacity of the method according to the invention.

[0027] The present invention further relates to a fuel cell vehicle comprising a cooling system as described above, which is designed to carry out a method as described above.

[0028] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0029] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0030] The figures are described in a coherent and comprehensive manner; identical components are assigned the same reference symbols. This shows: Fig. 1 a schematic representation of an embodiment of the cooling system according to the invention comprising a cooling circuit, wherein the indirect condenser is arranged in a feed line of a high-temperature cooler, Fig. 2 a schematic representation of a cooling system not covered by the invention comprising a cooling circuit, wherein a low-temperature cooling circuit is arranged at the indirect condenser.

[0031] Fig. Figure 1 shows a schematic representation of the cooling system 10 according to the invention for increasing the cooling capacity of a drive unit with a cooling circuit comprising a branch 11 coming from a fuel cell system and a branch 12 going to the fuel cell system, in particular a high-temperature cooling circuit, comprising a high-temperature cooler 18, wherein the cooling system 10 includes an indirect condenser 13 and a chiller 15. The indirect condenser 13 is arranged in an intermediate circuit 14. The chiller 15 is configured to cool a coolant and thus provide cooling capacity. The indirect condenser 13 is arranged in a supply line 19 of the high-temperature cooler 18. By integrating the indirect condenser 13 into the supply line 19 of the high-temperature cooler 18, a particularly compact design is achieved.The use of an additional indirect condenser 13 also makes it possible to reduce the amount of refrigerant and eliminate the need for an accumulator or receiver. This reduces the complexity of the cooling system 10, resulting in a more compact design. Furthermore, it is not necessary to place an additional heat exchanger in the front of the vehicle. The intermediate circuit 14 also includes a compressor 16 and an expansion valve 17. The intermediate circuit 14 allows the indirect condenser 13 to be integrated into the cooling system 10 and increases the cooling capacity of the cooling circuits 11 and 12, particularly the high-temperature cooling circuit. The indirect condenser 13 is designed to transfer heat, especially condensation heat, to the refrigerant in the supply line 19 of the high-temperature cooler 18.The indirect condenser 13 thus prevents the heat of condensation from being released directly into the air, but instead transfers it to a medium, in this case the coolant of the cooling circuits 11 and 12. This increases the cooling capacity of the cooling system 10 of the drive unit and simultaneously improves operational reliability. The intermediate medium is preferably designed to be coolable. The use of an indirect condenser 13 reduces the required amount of coolant compared to a system known from the prior art. Furthermore, an accumulator can be omitted, thereby reducing the amount of flammable liquids in the cooling system 10.

[0032] Furthermore, the Fig. Figure 1 shows a schematic representation of an embodiment of a method according to the invention for increasing the cooling capacity of a drive unit with a high-temperature cooling circuit 11 and 12, comprising a cooling system 10 as described above, with a high-temperature cooler 18, an intermediate circuit 14, an indirect condenser 13, a chiller 15, a compressor 16, and an expansion valve 17. The intermediate circuit 14 with the indirect condenser 13 is traversed, and heat is extracted from the intermediate medium by the indirect condenser 13. The intermediate circuit 14 includes the indirect condenser 13, the chiller 15, the compressor 16, and the expansion valve 17. The chiller 15 cools the coolant, transferring heat to the intermediate medium, and thus provides cooling capacity.The intermediate circuit 14 makes it possible to integrate indirect condensation through the indirect condenser 13 into the cooling system 10 and to increase the cooling performance of the cooling circuits 11 and 12, especially the high-temperature cooling circuit.

[0033] In the Fig. 2 is a cooling system 20 for increasing the cooling capacity of a drive unit with a cooling circuit 11 and 12, in particular a high-temperature cooling circuit, wherein the cooling system 20 comprises an indirect condenser 13, which is configured to transfer heat from an intermediate medium, and a chiller 15, which is configured to provide cooling capacity. The indirect condenser 13 is configured to transfer heat, in particular condensation heat, from the intermediate medium to a medium passing through a low-temperature circuit 21 and 22. The intermediate medium is preferably designed to be coolable. As in Fig. As shown in Figure 2, the cooling system 20 comprises a low-temperature cooling circuit with a low-temperature cooler 23 and is designed to absorb heat from the indirect condenser 13 and dissipate it to the ambient air via the low-temperature cooler 23. The cooling capacity of the cooling system 20 according to the invention can be further increased by the inclusion of a low-temperature cooling circuit.

[0034] Furthermore, the Fig. 2. A method for increasing the cooling capacity of a drive unit with a high-temperature cooling circuit, comprising a cooling system, a cooling circuit 11 and 12, a high-temperature cooler 18, and further comprising an intermediate circuit 14 with an indirect condenser 13, an expansion valve 17, a chiller 15, and a compressor 16. The intermediate circuit 14 with the indirect condenser 13 is traversed by the intermediate medium. Heat is extracted from the intermediate medium by the indirect condenser 13, while the chiller 15 releases heat to the intermediate medium. The chiller 15 cools a coolant that traverses the cooling circuits 11 and 12, thus providing cooling capacity. The heat extracted from the coolant by the chiller 15 is transferred to the intermediate medium. Subsequently, the intermediate medium is cooled again by the indirect condenser 13, the cooling capacity of the indirect condenser 13 being higher than that of the cooling circuit 11 and 12. Fig.The cooling capacity of the cooling system 20 can be further increased by transferring heat from the indirect condenser 13 to a low-temperature cooling circuit 21 and 22 with a low-temperature cooler 23. The low-temperature cooling circuit 21 and 22 then dissipates the heat to the ambient air via the low-temperature cooler 23, thereby achieving an additional increase in the cooling capacity of the cooling system 20. Reference symbol list 10 Cooling system 11 Cooling circuit (coming from the fuel cell system) 12 Cooling circuit (going to the fuel cell system) 13 indirect capacitor 14 Intermediate circuit 15 Chiller 16 compressors 17 Expansion valve 18 high-temperature coolers 19 High-temperature cooler pre-flow 20 Cooling system with additional low-temperature circuit 21 Low-temperature circuit (going to the low-temperature cooler) 22 Low-temperature circuit (coming from the low-temperature cooler) 23 Low-temperature coolers

Claims

[1] Cooling system (10, 20) for increasing the cooling capacity of a drive unit with a cooling circuit (11, 12), namely a high-temperature cooling circuit, which includes a coolant flowing through the cooling circuit (11, 12), a high-temperature cooler (18), at least one intermediate circuit (14) with an intermediate medium flowing through the respective intermediate circuit (14), further in the intermediate circuit (14) at least one chiller (15) configured to transfer heat from the cooling circuit (11, 12) to the at least one intermediate medium, and further in the intermediate circuit (14) at least one indirect condenser (13), wherein the cooling system (10, 20) includes a circuit (11, 12; 21, 22) with a medium flowing through the circuit, and the at least one indirect condenser (13) is arranged in the circuit (11, 12; 21, 22) and is configured to transfer heat from the respective intermediate medium to the medium within of the circulatory system (11, 12;21, 22) to transfer, ; characterized by , that the cooling circuit (11, 12) comprises a branch (11) coming from a fuel cell system and a branch (12) going to the fuel cell system, wherein the indirect condenser (13) is integrated into a feeder (19) of the high-temperature cooler (18) on the coming branch (11), and wherein the chiller (15) is integrated into the going branch (12). [2] Cooling system (10, 20) according to claim 1, characterized by that the intermediate medium is designed to be coolable. [3] Cooling system (10, 20) according to one of the preceding claims, characterized by that the intermediate medium includes a refrigerant. [4] Cooling system (10, 20) according to one of the preceding claims, characterized by , that the intermediate circuit (14) additionally includes at least one compressor (16) and at least one expansion valve (17). [5] Cooling system (10) according to any one of the preceding claims, characterized by, that the medium within the circuit (11, 12), to which the indirect condenser (13) transfers heat, is the coolant within the cooling circuit (11, 12). [6] Use of a cooling system according to one of claims 1 to 5 in a method for increasing the cooling capacity of a drive unit with a cooling circuit (11, 12), namely a high-temperature cooling circuit, which includes a coolant passing through the cooling circuit (11, 12), a high-temperature cooler (18), at least one intermediate circuit (14) with a respective intermediate medium passing through the respective intermediate circuit (14), further in the intermediate circuit (14) at least one chiller (15) configured to transfer heat from the cooling circuit (11, 12) to the at least one intermediate medium, and further in the intermediate circuit (14) at least one indirect condenser (13), wherein the at least one indirect condenser (13) is arranged in a circuit (11, 12; 21, 22), wherein the circuit (11, 12; 21, 22) is a circuit (11, 12;21, 22) has a medium passing through it, and heat is transferred from the respective intermediate medium to the medium via the indirect condenser (13).; [7] Use according to claim 6, wherein heat is transferred to the coolant passing through the cooling circuit (11, 12) by means of the at least one indirect condenser (13) arranged in a feeder (19) of the high-temperature cooler (18). [8] Fuel cell vehicle comprising a cooling system (10, 20) according to any one of claims 1 to 5 and configured to perform a method corresponding to the use of claims 6 to 7.

Images