Heat pump unit, thermal management system, axle assembly, and vehicle

Abstract

The invention relates to a cyclic process device (10), in particular a heat pump, for a vehicle, in particular an electric vehicle or a hybrid vehicle, comprising: at least two heat exchangers (11) for transferring thermal energy, a compressor unit (12) for compressing a fluid, an expansion valve (13) for reducing the pressure of the fluid, and a housing (14) for receiving the at least two heat exchangers (11), the two heat exchangers (11) being at least partly integrally formed on the housing (14).

Description

[0001] ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0002] Heat pump unit, thermal management system, axle assembly and vehicle

[0003] The present invention relates to a heat pump unit as well as a thermal management system, an axle assembly and a vehicle with such a heat pump unit.

[0004] Heat pumps, especially for vehicles, are well-known. A heat pump typically consists of a compressor, which can be driven mechanically or electrically, that draws in a gaseous fluid, compresses it, and then feeds it via a pipe or hose to a heat exchanger, such as a condenser. In the condenser, thermal energy is extracted from the fluid. This cools the fluid until it falls below its boiling point, causing it to undergo a phase change and become at least partially liquid. The liquid fluid is then expanded by passing through an expansion valve. The fluid is then fed to another heat exchanger, an evaporator, where energy is added, causing it to return to its gaseous state. The compressor then draws in the fluid, and the process begins again.

[0005] It is known that such devices or systems are assembled from standardized components or modified individual components. Furthermore, the individual components are connected with lines, particularly hoses or pipes. These systems therefore require a large amount of installation space, as the individual and standard components can only be adapted to a limited extent in terms of shape and size. Consequently, the power density is low and the weight is high. In addition, numerous interfaces are required, which represent potential sources of error or unavoidable leakage, meaning these systems require regular maintenance and fluid can escape into the environment.

[0006] It has thus become clear that there is a need to provide an improved, and in particular more compact, heat pump unit. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0007] The object of the present invention is to provide a heat pump unit that can solve the above problem. It is further an object of the present invention to provide a thermal management system, an axle assembly, and a vehicle.

[0008] According to the present invention, the problem is solved with a heat pump unit having the features of claim 1, with a thermal management system having the features of claim 8, with an axle assembly having the features of claim 9 and with a vehicle having the features of claim 10.

[0009] One aspect of the present invention relates to a heat pump unit for a vehicle, in particular an electric vehicle or a hybrid vehicle, with a refrigerant circuit, wherein the refrigerant circuit comprises: at least one evaporator and one condenser for transferring thermal energy, a compressor unit for compressing a fluid, at least one expansion valve for reducing the pressure of the fluid, a housing in which the refrigerant circuit is arranged, wherein the housing is designed to be substantially fluid-tight.

[0010] In contrast to the current state of the art, this approach allows for a heat pump unit with a compact, and therefore space-saving, design and more efficient operation. In other words, a very compact refrigeration circuit with a small amount of fluid and thus high power density can be achieved. The increased efficiency is due, among other things, to reduced energy losses to the environment. A compact design can be achieved by eliminating connections (e.g., hoses) between individual components of the refrigeration circuit. This more compact design reduces or eliminates leaks and corrosion of fluid lines, as the distances between the individual components of the heat exchanger, and thus the fluid lines, can be shortened or even eliminated entirely.

[0011] Similarly, the number of leakage points between fluid lines and components of the heat pump unit can be reduced. An advantage over the known state of the art is that the use of flexible fluid lines can be largely or completely avoided (ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25), especially since these flexible lines are highly susceptible to leaks.

[0012] The heat pump unit is preferably a heat pump for a vehicle, in particular an electric vehicle or a hybrid vehicle. The heat pump unit includes a refrigerant circuit. The refrigerant circuit is designed to circulate a refrigerant within it. The refrigerant circuit comprises an evaporator for evaporating a fluid and a condenser for liquefying a fluid. The evaporator and the condenser can also be referred to as heat exchangers. The two heat exchangers are designed to transfer thermal energy from a refrigerant circuit to a coolant circuit. For example, the heat exchangers can each be thermally coupled to a cooling circuit of a vehicle's thermal management system. In particular, a high-temperature circuit can be thermally coupled to the condenser and a low-temperature circuit to the evaporator.

[0013] The compressor unit is specifically designed to compress a fluid. The compressor unit preferably includes a drive unit. The drive unit can, for example, be an electric motor. The drive unit can be arranged in the housing together with the compressor unit. The compressor unit and the drive unit are preferably formed as a single unit. In one embodiment, the compressor unit optionally includes a scroll compressor, a rotary piston compressor, or a turbo compressor. Other suitable compressor types are also possible. The selected compressor can preferably be integrated as a single unit within the housing to provide a one-piece heat pump unit or a one-piece refrigerant circuit.

[0014] The heat pump unit also includes at least one expansion valve for regulating the fluid pressure. The expansion valve may consist of a valve, an orifice, and / or a throttle. Alternatively, the expansion valve may include a pressure regulating valve. The expansion valve is located downstream of the condenser in the direction of refrigerant flow. The expansion valve is designed to reduce the pressure acting on the refrigerant. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0015] The expansion valve can preferably be completely integrated or arranged within the housing, so that it has no contact with the environment. Alternatively, the expansion valve can be mounted externally on the housing or inserted into the housing. The expansion valve can be arranged in a fluid-tight manner on or inserted into the housing. Furthermore, the expansion valve can be positioned close to the condenser to minimize the length of the liquid refrigerant lines.

[0016] The housing is essentially fluid-tight. In particular, the housing is designed such that essentially no gas, for example air, and no liquid, for example water, can enter or escape from the housing. The term "essentially" can be understood to mean a deviation of ±15%, particularly ±10%, and particularly ±5%. The reference quantity can be the output quantity of fluid that passes a system boundary of the refrigerant circuit. The housing is preferably designed such that the refrigerant circuit is protected from external influences. Furthermore, essentially no refrigerant can escape from the housing and enter the environment during operation. This means that the refrigerant circuit can be essentially completely enclosed by the housing. The housing is preferably made of aluminum.The housing can be manufactured by deep drawing, roll forming, die casting, or other suitable manufacturing processes. The housing is designed to be fluid-tight. This means that essentially no substances can enter or escape from the inside. In particular, the housing can be welded and / or brazed. The housing allows the cycle device to be handled as a single unit. The heat pump unit, for example, can be designed to be installed in a vehicle, especially an electric vehicle.

[0017] The refrigerant circuit, or its components, are located within the housing. Additional components may also be located within the housing. Furthermore, it is possible that the refrigerant circuit is at least partially integral with the housing. This means that the refrigerant circuit is at least partially part of the housing or forms part of the housing itself. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0018] The evaporator and / or the condenser may be formed as a single unit with the housing, at least in sections. In particular, it is conceivable that the evaporator and / or the condenser and / or the compressor unit and / or the expansion valve cannot be removed from the housing without damage. Alternatively or additionally, the two heat exchangers may be positively connected, frictionally connected, and / or materially connected to the housing.

[0019] In one embodiment, the housing hermetically encloses the refrigerant circuit and / or the refrigerant circuit is hermetically arranged within the housing. In other words, the refrigerant circuit is a hermetically sealed system within the housing. This means that the housing is sealed so fluid-tight that no liquid or gaseous substance can enter or escape. In other words, the housing is completely fluid-tight. In particular, the housing can be described as impermeable. It is especially possible for the housing to be hermetically sealed by welding and / or brazing. Other suitable material-locking, form-locking, and / or force-locking methods are also conceivable.

[0020] In one embodiment, the housing has a high-pressure area and a low-pressure area, with the evaporator and compressor unit located in the low-pressure area and the condenser and expansion valve in the high-pressure area. The high-pressure area is the area where the refrigerant has a higher pressure than in the low-pressure area. More precisely, the high-pressure area is located downstream of the compressor unit in the refrigerant circuit, in the direction of refrigerant flow. The low-pressure area is the area where the refrigerant has a lower pressure than in the high-pressure area. More precisely, the low-pressure area is located downstream of the expansion valve in the refrigerant circuit, in the direction of refrigerant flow.

[0021] In one embodiment, the housing comprises and / or forms at least one fluid line, wherein the fluid line is configured to fluidically connect the evaporator, the condenser, the compressor unit, and / or the expansion valve. In particular, the fluid line is configured such that the evaporator, ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0022] The condenser, compressor unit, and / or expansion valve are directly fluidically connected. In other words, at least one fluid line can be integrated into the housing. Furthermore, the housing can have or incorporate multiple fluid lines. "Directly" here means that no other element is positioned between two directly connected elements. The at least one fluid line can, for example, be designed as a channel in the housing wall. The at least one fluid line makes it possible to reduce or eliminate the need for additional fluid lines, such as hoses or pipes. The at least one fluid line can be designed for a fluid, such as a refrigerant and / or a coolant. The fluid can be a gas and / or a liquid. Alternatively or additionally, the housing can have at least one connection for at least one fluid line.Furthermore, this method can reduce the number of sealing points in the refrigerant circuit. This, in turn, reduces the risk of a leak, where refrigerant can escape.

[0023] In one embodiment, the heat pump unit includes an additional heat exchanger and / or an additional expansion valve. This heat exchanger can essentially be understood as an additional evaporator. This additional, or second, evaporator can be arranged or connected in parallel to the first evaporator in the refrigerant circuit. The refrigerant flowing through the second evaporator has a different pressure level than the refrigerant flowing through the first evaporator. The pressure level of the refrigerant flowing through the first evaporator can be referred to as the low-pressure level. The pressure level of the refrigerant flowing through the second evaporator is higher than the pressure level of the refrigerant flowing through the first evaporator and can be referred to as the medium-pressure level, since the pressure is higher than in the low-pressure range but lower than in the high-pressure range.The intermediate pressure level can be adjusted by the additional expansion valve. The additional expansion valve is preferably arranged in a fluid line parallel to the expansion valve associated with the first evaporator. The second evaporator can therefore also be referred to as the intermediate pressure evaporator. The intermediate pressure evaporator can be designed as a refrigerant-coolant heat exchanger. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25.

[0024] The expansion valves are preferably located close to the condenser, particularly in the area of ​​the oil separator. This allows the length of the line containing the liquid refrigerant phase to be kept as short as possible. Alternatively, the expansion valves can also be located between the evaporator and the compressor unit or between the evaporator and the medium-pressure evaporator. The expansion valves can be integrated outside the evaporator and / or the medium-pressure evaporator, or within the evaporator and / or the medium-pressure evaporator.

[0025] In one embodiment, the refrigerant circuit includes a vapor injection device. This incorporates a second heat exchanger, in particular a refrigerant-to-refrigerant heat exchanger (in other words, a gas cooler), and an additional expansion valve that reduces the refrigerant pressure to a medium level. Both the medium-pressure evaporator and the vapor injection device require additional injection ports or valves in the compressor unit leading to a compression zone with a medium-pressure level (suction pressure < medium pressure < discharge pressure).

[0026] In one embodiment, the refrigerant circuit includes an internal heat exchanger, in particular a refrigerant-to-refrigerant heat exchanger, in other words, a gas cooler. The internal heat exchanger is preferably arranged upstream of the expansion valve. This allows thermal energy or heat to be transferred from the refrigerant from a section upstream of the expansion valve to a section upstream of the compressor.

[0027] In one embodiment, the heat exchanger and / or the additional heat exchanger or the medium-pressure evaporator has an inlet for the refrigerant, which, when installed in the heat pump unit, is located in a lower half of the heat pump unit, and an outlet, which, when installed in the heat pump unit, is located in an upper half. The inlet is designed to be connected to a medium-pressure line. When installed in the heat pump unit, the medium-pressure line can be located in the lower housing half and fluidly connected to the medium-pressure evaporator. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25. The refrigerant can enter the medium-pressure evaporator through the inlet, flow through it, and exit through the outlet in the upper half. From there, the refrigerant can be collected and, when installed in the heat pump unit, directed towards the compressor unit.The refrigerant is transported to the injection section. There, it can be introduced into the medium-pressure zone of the compressor via additional inlet openings.

[0028] In one embodiment, the evaporator and / or the compressor unit and / or the condenser and / or the expansion valve are arranged in a series. More precisely, components of the refrigerant circuit are arranged at least partially side by side in a series. In particular, one component borders the next component in one direction, for example, a longitudinal direction of the heat pump unit, and especially a single component. The components preferably border each other in a longitudinal direction. This allows for a compact design of the heat pump unit. Furthermore, it eliminates the need for long pipes or hose sections.

[0029] In one embodiment, the housing has a cooling section, which preferably borders the compressor unit at least partially. More preferably, the cooling section can border the evaporator. In particular, the cooling section can be arranged downstream of the evaporator in the refrigerant flow direction. The cooling section can preferably be located inside the housing. The cooling section can, in particular, be configured to cool a drive unit of the compressor unit. Preferably, the cooling section surrounds or encloses the drive unit at least partially and / or borders the drive unit at least partially in the longitudinal direction. Alternatively or additionally, the cooling section can include channels that extend through the drive unit. The cooling section can include a free space that surrounds the drive unit at least partially.The refrigerant exiting the evaporator can be routed to the cooling section. This allows the drive unit to be cooled by the gaseous refrigerant. The gaseous refrigerant flows through the cooling section. Subsequently, the gaseous refrigerant is routed to a compression section of the compression unit. (ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25)

[0030] In one embodiment, the compressor unit is arranged axially within the heat pump unit, between the evaporator and the condenser. An axial direction can be understood as a longitudinal direction. Preferably, the evaporator is adjacent to an inlet of the compression unit, and the condenser is adjacent to an outlet of the compression unit. This allows the evaporator and the condenser to be connected directly to the compression unit. "Directly" or "immediately" means that no other component is interposed. Furthermore, the evaporator and the condenser can be connected to each other without additional pipes or hoses.

[0031] In one embodiment, control electronics are arranged on the outer surface of the housing. Alternatively or additionally, power electronics can be arranged on the outer surface. The control electronics and / or power electronics can be located in a secondary housing. The secondary housing can be connected to the housing of the heat pump unit, in particular by a screw connection. This allows the control electronics and / or power electronics to be detached from the housing. This enables maintenance or replacement of the electronics without having to open the housing of the heat pump unit. In one embodiment, the heat pump unit includes at least one interface for transmitting electrical energy and / or a signal. For example, this interface can be used to supply power to the compressor or to provide a signal connection to a control unit.In an alternative embodiment, the control electronics or the power electronics can be part of the housing or integrated into the housing.

[0032] In one embodiment, at least one sensor, in particular a temperature and / or pressure sensor, is arranged in the housing. The sensor is preferably coupled to the control electronics for signal transmission. In particular, the sensor is coupled to the control electronics for wireless signal transmission. The sensor is preferably arranged at an inlet or suction side of the compressor unit. Alternatively or additionally, the sensor can be arranged in the evaporator, in particular in the direction of refrigerant flow in a second half of the evaporator. If the refrigerant circuit has a medium-pressure evaporator and a further expansion valve, a further sensor, in other words a second sensor inlet of the compressor unit for the medium-pressure refrigerant, can be arranged. Furthermore, the second sensor can be arranged in the medium-pressure evaporator.Furthermore, an additional sensor can be located on the compressor unit, particularly at one of its outputs. This sensor can also be located on the condenser. This allows the operation of the heat pump unit to be monitored. For example, a desired pressure can be set. Additionally, faults or leaks can be detected early.

[0033] In one embodiment, the heat pump unit can preferably include several pressure and temperature sensors integrated into the refrigerant circuit for controlling the heat pump. In the low-pressure section, a pressure sensor can be arranged upstream or downstream of the evaporator, and a temperature sensor can be arranged downstream of the evaporator, preferably as close as possible to the compressor unit inlet. In a wet vapor environment, the pressure sensor can be replaced by another temperature sensor downstream of the expansion valve, upstream of the evaporator, or in the first half of the evaporator. Low-pressure monitoring for safety reasons is an alternative due to the fluid-tight or hermetic housing. In the high-pressure section, a temperature sensor and a pressure sensor can be arranged, particularly as close as possible to the compressor unit outlet, to monitor the high pressure and limit the temperature for safety reasons.In this case, the pressure sensor can also be replaced by another temperature sensor in the first half of the condenser, especially in a wet steam area.

[0034] In one embodiment, the housing is manufactured from a single part or from several parts. For example, the housing can be manufactured from a single tube. Alternatively, it can be manufactured from several tube sections (ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25). Preferably, the several tube sections are joined together by a material-bonded process, in particular welding or brazing. Consequently, the housing can have a substantially cylindrical geometry. In particular, the housing can have a cylindrical geometry at least partially. This means that the housing has a central longitudinal axis, at least partially, which passes through the center point of a cross-section of a cylindrical body. It is also conceivable that further shapes or elements are arranged on or project from the cylindrical geometry.Alternatively or additionally, the housing can have a polygonal geometry in certain sections. Preferably, the evaporator and / or the condenser and / or the compressor unit are adapted to the geometry of the housing or have a geometry that corresponds at least in certain sections.

[0035] In one embodiment, the expansion valve and / or the additional expansion valve is arranged in the area of ​​an oil separator. The oil separator is part of the compressor unit. The oil separator is preferably a cyclone separator. The oil separator and the expansion valves can thus contribute to a more compact design.

[0036] In one embodiment, at least the evaporator and / or the condenser and / or the medium-pressure evaporator is designed as a plate heat exchanger, in particular wherein plate elements of the plate heat exchanger are stacked in a radial and / or axial direction. The phrase "stacked in a radial direction" means that the plates are stacked radially away from a central longitudinal axis. In other words, the plates are each oriented towards the central longitudinal axis. It is possible that the individual plates have a circular arc shape in cross-section. The phrase "stacked in an axial direction" means that the plates are stacked in the direction of the central longitudinal axis. In other words, the central longitudinal axis is arranged orthogonally to the plates. This means that the central longitudinal axis penetrates the plates. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0037] In one embodiment, the refrigerant circuit does not include a separate collection unit or reservoir for the refrigerant. Preferably, the collection unit is integrated into the condenser or the piping. Alternatively, the refrigerant circuit can also include an accumulator or separator, which is preferably located downstream of the evaporator or integrated into the evaporator. Alternatively, the collection unit can be located on the condenser or on the housing.

[0038] In one embodiment, the compressor unit is axially adjacent to at least one of the two heat exchangers. In particular, the compressor unit is directly adjacent to at least one of the two heat exchangers. The terms "directly" and "immediately" mean that, at least in some sections, no further element, component, or part is located between the compressor unit and the heat exchanger. It is possible that a gap, free space, or fluid line is located between the compressor unit and the heat exchanger. Furthermore, it is possible that the compressor unit and the heat exchanger are in contact, at least in some sections.

[0039] In one embodiment, the two heat exchangers are arranged parallel to each other, at least partially, in the axial direction. This means that the heat exchangers are preferably arranged side by side. In particular, the heat exchangers can be arranged side by side parallel to a central longitudinal axis. Preferably, the heat exchangers are designed as plate heat exchangers. It is also possible for the heat exchangers to be arranged offset from each other, at least partially. This allows for a compact design of the heat pump unit.

[0040] In one embodiment, the compressor unit is arranged axially within the heat pump unit between the evaporator and the condenser. More precisely, the compressor unit is axially enclosed or bounded by a heat exchanger on each side. In other words, the compressor unit can be sandwiched between the ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0041] The compressor unit is arranged with heat exchangers. The compressor unit is thus axially adjacent to each heat exchanger. The compressor unit and the heat exchangers are preferably arranged directly adjacent to one another. In other words, the heat exchangers and the compressor unit can be arranged axially one behind the other within the housing. It is advantageous to arrange the heat exchanger designed as a condenser at one outlet of the compressor unit, followed by the heat exchanger designed as an evaporator. This is particularly advantageous because the expansion valve can then be positioned downstream of the condenser in the fluid flow direction. Preferably, one heat exchanger is arranged at each axial end of the housing.

[0042] Another aspect of the present invention relates to a thermal management system comprising a heat pump unit according to one of the preceding embodiments. A thermal management system is defined as a system that regulates the temperature of at least two consumers. A consumer is therefore a device to be cooled or heated. Preferably, a consumer can be an electric machine. Furthermore, a consumer can be an inverter. Additionally or alternatively, a consumer can be a passenger compartment. Advantageously, a consumer can be a battery.

[0043] Another aspect of the present invention relates to an axle assembly with a heat pump unit according to one of the preceding embodiments.

[0044] Another aspect of the present invention relates to a vehicle with a thermal management system according to the preceding embodiment and / or an axle assembly according to the preceding embodiment and / or a heat pump unit of one of the preceding embodiments.

[0045] Another aspect of the present invention relates to a method for manufacturing a heat pump unit, particularly according to one of the preceding embodiments, comprising: manufacturing a heat pump unit wherein a refrigerant circuit is arranged at least partially hermetically in a housing. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0046] Another aspect of the present invention relates to the use of a heat pump unit in an axle assembly, particularly according to the preceding embodiment and / or in a vehicle, particularly according to the preceding embodiment.

[0047] Individual features and embodiments of the present invention can be combined with other features in other embodiments to form new embodiments. Advantages and further developments mentioned for the features or embodiments also apply analogously to the new embodiments. Further developments and advantages mentioned in connection with the apparatus also apply analogously to the method and vice versa.

[0048] The following is an exemplary description of the revelation with reference to the accompanying figures, which show

[0049] Figure 1: a schematic view of a refrigerant circuit of a heat pump unit;

[0050] Figure 2: another schematic view of a refrigerant circuit of a

[0051] Heat pump unit;

[0052] Figure 3: a sectional view of an embodiment of a heat pump unit according to the invention;

[0053] Figure 4: another sectional view of an embodiment of a heat pump unit according to the invention; and

[0054] Figure 5: a sectional view of an embodiment of a heat pump unit according to the invention.

[0055] Figure 1 shows a refrigerant circuit of a heat pump 10. The refrigerant circuit comprises an evaporator 1, a condenser 12, a compression unit 13, and an expansion valve 14. A refrigerant circulates in the refrigerant circuit. The direction of circulation is indicated by arrows. The refrigerant circuit is designed to enable a cyclic process. A cyclic process can be described as a sequence of state changes of a fluid, referred to as the working fluid (e.g., here, refrigerant), along a closed trajectory within the fluid's state space. The cyclic process of the refrigerant circuit according to Figure 1 can comprise the following steps: The evaporator 11 is thermally coupled to a first cooling circuit. The condenser 12 is thermally coupled to a second cooling circuit. The evaporator 11 is designed to evaporate the refrigerant.The condenser 12 is designed to liquefy the refrigerant. The condenser 12 can therefore also be referred to as a condenser. The compressor unit 13 is designed to compress the gaseous refrigerant, such as propane (R-290), carbon dioxide (R-744), or R-1234yf. The compressor unit 13 can, for example, be a scroll compressor. In a downstream condenser 12, the compressed refrigerant can be cooled and thereby converted into a liquid state. This extracts thermal energy from the refrigerant in the form of heat and transfers it to the second refrigeration circuit. At least one expansion valve 14 is provided downstream of the condenser 12, which reduces the pressure of the refrigerant. This lowers the pressure and thus the temperature of the refrigerant in the refrigeration circuit.In the downstream evaporator 11, heat energy from the first cooling circuit is absorbed, thus cooling the first cooling circuit. From there, the cycle can be repeated in the thermodynamic device, starting with the compressor unit 13. In other words, the first and second cooling circuits can both exchange thermal energy.

[0056] Figure 2 shows another schematic view of a refrigeration circuit. The refrigeration circuit shown includes an additional evaporator 16, which can be referred to as a precooler. Furthermore, the refrigeration circuit includes an additional expansion valve 19. The additional expansion valve 19 is arranged downstream of the condenser 12 in the direction of refrigerant flow. The additional expansion valve 19 is located in a fluid line running parallel to or connected to the expansion valve 14 (ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25).

[0057] The refrigeration cycle shown essentially follows a cyclical process as described in Figure 1. However, the refrigerant circuit has a high-pressure section, a medium-pressure section, and a low-pressure section.

[0058] After the condenser 12, the refrigerant, which is at a high pressure, flows in two separate parallel fluid lines through the expansion valve 14 and the additional expansion valve 19. In the expansion valve 14, the refrigerant pressure is reduced to a low pressure. In the additional expansion valve 19, the refrigerant pressure is reduced to a medium pressure. The refrigerant at the low pressure flows to the evaporator 11. The refrigerant at the medium pressure flows to the precooler 16. The evaporator 11 and the precooler 16 are thermally coupled to a low-temperature refrigerant circuit NK. The evaporator 11 and the precooler 16 are arranged in series in the low-temperature refrigerant circuit. More precisely, the evaporator 11 is located downstream of the precooler 16 in the flow direction of the low-temperature circuit NK.

[0059] The low-pressure and high-pressure refrigerants are combined in the compressor unit 13. The compressor unit 13 comprises a scroll compressor. The scroll compressor has a drive unit. The drive unit comprises an electric motor with a stator and a rotor. The rotor is mounted on a shaft. An orbiting scroll element is located at one axial end of the shaft. The orbiting scroll element is driven by the shaft. The orbiting scroll element engages with a stationary scroll element. The two scroll elements comprise corresponding spiral geometries that interlock, so that the orbiting motion compresses the gaseous refrigerant. The compressor unit 13 is located downstream of the evaporator 11 and the precooler 16 in the direction of refrigerant flow.Compressor unit 13 is configured to compress the low-pressure gaseous refrigerant flowing from evaporator 11 and the medium-pressure gaseous refrigerant flowing from precooler 16. The low-pressure and medium-pressure gaseous refrigerants flow in separate fluid lines towards compressor unit 13. Compressor unit 13 has defined or predetermined injection openings for the low-pressure and medium-pressure refrigerants.

[0060] The compressor unit 13 includes an oil separator 20. The oil separator 20 is designed as a cyclone separator. The oil separator 20 has a conical geometry. The apex of the cone has an opening for the separated oil. In the assembled state, the opening is directed downwards in the direction of gravity. The cyclone separator has an outlet for the gaseous refrigerant. In the assembled state, the refrigerant outlet is located at the top of the cyclone separator in the direction of gravity. The oil separator can be integrated into the compressor unit 13 or into the housing 15.

[0061] The condenser 12 is arranged in the direction of refrigerant flow after the compressor unit 13 and the oil separator. The condenser 12 is configured to liquefy the gaseous refrigerant. The condenser 12 is thermally coupled to a high-temperature refrigerant circuit HK.

[0062] The flow directions of the low-temperature coolant circuit (LCC) and the high-temperature coolant circuit (HTC) are opposite to the flow direction of the refrigerant in their respective sections. The low-temperature coolant circuit (LCC) can, for example, be thermally coupled to a cooling system, and the high-temperature circuit to a heating system. The temperature to which the high-temperature circuit is cooled can be, for example, 40°C. This temperature can be used simultaneously to heat a consumer such as the passenger compartment and to cool another consumer such as an electric motor. The low-temperature circuit is cooled to a lower temperature than the high-temperature circuit. This allows the cooling capacity to be concentrated on the low-temperature circuit, to which the consumer with the highest cooling demand, such as power electronics, is connected.This optimizes the provision of cooling capacity and, for example, allows the compressor unit 13 to be dimensioned smaller.

[0063] Figure 3 shows a sectional view of a heat pump unit 10. The heat pump unit 10 comprises a refrigerant circuit, which essentially corresponds to the refrigeration circuit shown in Figure 1. The refrigerant circuit is arranged in a housing 15. The housing 15 comprises several parts. More precisely, the housing 15 is made of three components that are connected to one another, in particular by welding. The housing 15 is fluid-tight. In particular, the housing 15 can hermetically seal the refrigerant circuit. Control electronics 21 and / or power electronics are arranged on an outer surface of the housing 15. The control electronics 21 and / or the power electronics are arranged in a separate housing. The separate housing is connected to the housing 15 of the heat pump unit 10, in particular by a detachable connection.

[0064] The condenser 12 is arranged at a first axial end. The evaporator 11 is arranged at the axial end opposite the condenser 12. The oil separator 20 of the compressor unit 13 borders the condenser 12 along a longitudinal direction L. Furthermore, the expansion valve 14 is arranged between the condenser 12 and the compressor unit 13. The expansion valve 14 is arranged essentially along the longitudinal direction L in the region of the oil separator 20.

[0065] The evaporator 11 is thermally coupled to the low-temperature coolant circuit NK. The condenser 12 is thermally coupled to the high-temperature coolant circuit HK. The heat pump unit 10 has a coolant inlet 22 and a coolant outlet 23 for both the low-temperature coolant circuit NK and the high-temperature circuit. The coolant inlet 22 of the evaporator 11 is preferably located in an upper region of the heat pump unit 10 when installed, and the coolant outlet 23 of the evaporator 11 is preferably located in a lower region of the heat pump unit 10. The coolant inlet 22 of the condenser 12 is preferably located in a lower region of the heat pump unit 10 when installed, and the coolant outlet 23 of the condenser 12 is preferably located in an upper region of the heat pump unit 10. ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0066] Heat pump unit 10 is arranged. This means that the coolant inlet 22 and the coolant outlet 23 of the low-temperature coolant circuit NK and the high-temperature coolant circuit HK are arranged oppositely on the respective heat exchangers.

[0067] The compressor unit 13 is adjacent to the evaporator 11. More precisely, the drive unit of the compressor unit 13 is adjacent to the evaporator 11. The drive unit is at least partially enclosed by a cooling section 18. The cooling section 18 has a free space through which gaseous refrigerant exiting the evaporator 11 flows. In particular, the drive unit can be cooled by the refrigerant in a longitudinal or axial direction. The drive unit of the compressor unit 13 can thus be cooled by the refrigerant.

[0068] Figure 4 shows a sectional view of another heat pump unit 10, which comprises a housing made of three sub-components. The heat pump unit 10 according to Figure 4 has a refrigerant circuit that essentially corresponds to the refrigerant circuit according to Figure 2. Furthermore, the design of the heat pump unit 10 essentially corresponds to the design of the heat pump unit according to Figure 3, with the following differences: The heat pump unit 10 in Figure 4 has the additional expansion valve 19 and the additional heat exchanger 16 or precooler 16. The additional expansion valve 19 is arranged in the area of ​​the expansion valve 14. The precooler 16 is arranged at the axial end of the heat pump unit 10 opposite the condenser 12. The evaporator 1 borders the precooler 16 longitudinally L. The precooler 16, like the evaporator 11, is coupled to the low-temperature circuit NK.

[0069] Figure 5 shows another sectional view of a heat pump unit 10. In contrast to the heat pump unit according to Figure 4, the heat pump unit in Figure 5 has a one-piece housing 15. In Figure 5, the fluid lines in the housing 15 are shown schematically. A first fluid line F1 connects the condenser to the expansion valve 14 and the additional expansion valve 19. By ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25

[0070] Fluid line F1 carries the refrigerant at a high pressure. A second fluid line F2 extends from the expansion valve 14 to the evaporator 11. The refrigerant flows through the second fluid line F2 at a low pressure. A third fluid line F3 extends from the additional expansion valve 19 to the additional heat exchanger 16 or precooler. The refrigerant flows through the second fluid line F2 at a medium pressure. The fluid lines extend beneath an outer casing of the housing 15. When the heat pump unit 10 is installed, the fluid lines are located in a lower region of the housing 15. The fluid lines 22 can, for example, include a bore, such as an oval bore. Alternatively, the fluid lines can be annular or formed by a canned tube. The arrangement of the fluid lines can also be applied to the preceding embodiments.

[0071] Other embodiments of the present invention are possible and can be understood and carried out by persons skilled in the art when applying the claimed subject matter by studying the figures, the disclosure, and the appended claims. In particular, the respective parts / functions of each embodiment described above can also be combined with one another. Furthermore, various steps of the method can be carried out in a different order than disclosed herein. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are mentioned in interdependent claims does not mean that a combination of these measures cannot be advantageous. Any reference numerals in the claims should not be interpreted as limiting the scope of the claims.ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25.

[0072] Reference mark

[0073] F1 first fluid line

[0074] F2 second fluid line

[0075] F3 third fluid line

[0076] L Longitudinal direction

[0077] 10 heat pump units

[0078] 11 evaporators

[0079] 12 Capacitor

[0080] 13 Compressor unit

[0081] 14 Expansion valve

[0082] 15 cases

[0083] 16 additional heat exchangers

[0084] 17 Fluid line

[0085] 18 Cooling section

[0086] 19 additional expansion valve

[0087] 20 oil separators

[0088] 21 Control electronics

[0089] 22 Coolant inlet

[0090] 23 Coolant outlet

Claims

ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25 Patent claims 1. Heat pump unit (10) for a vehicle, in particular an electric vehicle or a hybrid vehicle, with a refrigerant circuit, wherein the refrigerant circuit comprises: at least one evaporator (1 1 ) and one condenser (12) for transferring thermal energy, a compressor unit (13) for compressing a fluid, at least one expansion valve (14) for reducing the pressure of the fluid, a housing (15) in which the refrigerant circuit is arranged, wherein the housing is substantially fluid-tight.

2. Heat pump unit (10) according to claim 1, wherein the housing (15) hermetically encloses the refrigerant circuit and / or the refrigerant circuit is hermetically arranged in the housing.

3. Heat pump unit (10) according to claim 1 or 2, wherein the housing has a high-pressure area (HB) and a low-pressure area (NB), wherein the evaporator (1 1 ) and the compressor unit (13) are arranged in the low-pressure area (NB) and the condenser (12) and the expansion valve (14) are arranged in the high-pressure area (HB).

4. Heat pump unit (10) according to one of the preceding claims, wherein the housing (15) comprises and / or forms at least one fluid line, wherein the fluid line is configured to fluidically connect the evaporator (1 1 ), the condenser (12), the compressor unit (12) and / or the expansion valve (14).

5. Heat pump unit (10) according to one of the preceding claims, wherein the heat pump unit comprises an additional heat exchanger (16) and / or an additional expansion valve (19). ZF Friedrichshafen AG File 304449 Friedrichshafen 2024-09-25 6. Heat pump unit (10) according to one of the preceding claims, wherein the evaporator (11) and / or the compressor unit (13) and / or the condenser (12) and / or the expansion valve are arranged in a series.

7. Heat pump unit (10) according to one of the preceding claims, wherein at least one sensor, in particular a temperature and / or pressure sensor, is arranged in the housing (15).

8. Thermal management system comprising a heat pump unit (10) according to any one of claims 1 to 7.

9. Axle assembly with a heat pump unit (10) according to one of claims 1 to 7.

10. Vehicle with a thermal management system according to claim 8 and / or an axle assembly according to claim 9 and / or a heat pump unit (10) according to any one of claims 1 to 7.

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