Valve unit, valve control, thermal management system and vehicle

Abstract

Valve unit (10), in particular for arrangement in a thermal management system, comprising: a valve (11) configured to vary a flow cross-section (Q') of a refrigerant circuit, an actuator (12) configured to control a pressure of a coolant in a coolant circuit, wherein the actuator (12) is configured to apply a control pressure to the valve (11) using the coolant, and wherein the valve (11) is configured to vary the flow cross-section (Q') of the refrigerant circuit depending on the control pressure.

Description

[0001] The present invention relates to a valve unit. Furthermore, the present invention relates to a valve control system, a thermal management system, and a vehicle.

[0002] It is known to use valves in heat pumps to adjust pressure or flow rate. Valves can also be used to partially or completely restrict the flow of refrigerant. For example, a valve can be designed as an expansion valve. The expansion valve can, for instance, regulate the pressure of a refrigerant downstream of a condenser. Valves that can be adjusted manually, for example with a handwheel, are known in the prior art. Alternatively, there are other types of valves for determining the flow rate, such as throttles or orifices. Electrically controlled valves are also known, which can usually be opened or closed by an electric motor or other actuator. However, large valve opening diameters and / or high pressures are required in refrigerant circuits.This results in very high forces being exerted by the drive unit to open and close the valves. Therefore, the requirements for such pressure regulating valves are very high.

[0003] It has therefore become clear that there is a need to provide an improved valve unit that is adapted to the above-mentioned requirements.

[0004] Therefore, it is an object of the present invention to provide a valve unit that addresses the above problem. It is further an object of the present invention to provide a valve control system, a thermal management system, and a vehicle.

[0005] The problem is solved by a valve unit having the features of claim 1, a valve control having the features of claim 8, a thermal management system having the features of claim 9 and a vehicle having the features of claim 10.

[0006] According to one aspect of the present invention, a valve unit is provided, which is particularly intended for arrangement in a thermal management system. The valve unit comprises a valve configured to vary the flow cross-section of a refrigerant circuit, and an actuator configured to control the pressure of a refrigerant in a refrigerant circuit, wherein the actuator is configured to apply a control pressure to the valve using the refrigerant, and wherein the valve is configured to vary the flow cross-section of the refrigerant circuit depending on the control pressure.

[0007] Compared to the prior art, the present invention offers the advantage that the forces required to open the valve can be reduced by pilot control via the actuator, while maintaining constant pressure and opening forces. To activate the valve, a control pressure, or activation pressure, is required. For this purpose, the coolant in the refrigerant circuit can be used, for example. In other words, the coolant can be used as a control fluid for the refrigerant side. This means that the coolant pressure can be regulated, and the valve in the refrigerant circuit can be activated depending on the regulated coolant pressure. This so-called pilot control reduces the forces required at the valve. This can reduce the cost of the valve. Furthermore, the size of the valve, and especially the actuator units, can be made smaller.This allows the valve unit to be controlled despite a large diameter and / or high pressure, without requiring disproportionately large forces. Furthermore, the valve can be actively controlled with a short response time to adjust the flow cross-section.

[0008] The valve unit can preferably be arranged or used in a thermal management system. The valve of the valve unit is designed to vary the flow cross-section of the refrigerant circuit. This means that the valve has a variable flow cross-section. The variable flow cross-section can be generated by a movable sealing element of the valve. The sealing element can be designed, for example, as a sliding element, a bolt element, a ball element, or a disc element. The flow cross-section can be varied by changing the position of the sealing element.

[0009] The actuator is located in the refrigerant circuit. Using the refrigerant, the actuator applies the control pressure to the valve. The control pressure is the pressure acting on the valve that causes a change in its flow cross-section. The refrigerant comprises a fluid, in particular water and / or oil. Other fluids suitable as refrigerants are also conceivable. The refrigerant can be in a liquid or gaseous state. Preferably, the sealing element can be operatively connected to the actuator. The sealing element can thus be directly subjected to the control pressure. When the control pressure reaches a predetermined value, the valve changes its state, or rather, its flow cross-section changes. The predefined pressure can also encompass a predefined pressure range by opening the flow cross-section of the refrigerant circuit, at least partially.In other words, the size of the opening of the flow cross-section can depend on the magnitude of the control pressure. Preferably, the valve has at least one sealing piston that limits or covers the flow opening. The sealing piston can be arranged on a longitudinal slide and designed to be displaceable in a longitudinal direction. During operation of the valve unit, the coolant can be in direct contact with a valve piston. It is also possible for the valve piston to be in contact with the coolant at least indirectly. Direct contact means that the valve piston has a direct contact surface with the coolant. Indirect contact means, for example, that a seal is arranged between the valve piston and the coolant.

[0010] In one embodiment, the actuator comprises a control valve arranged in the coolant circuit, wherein the control valve is preferably a direct-acting valve, and wherein the actuator preferably comprises an electric linear actuator. The electric linear actuator may comprise an electric actuator, a solenoid coil, and / or a shape-memory wire.

[0011] The actuator can be designed as an electromagnetic linear drive, in particular as a solenoid coil. The solenoid coil can also be referred to as an electromagnet. Electromagnets are simple, safe, and cost-effective drives for solenoid valves. As actuators, the electromagnets can, for example, move armatures or cores in the control valve without contact. The solenoid coil can be directly connected to the sealing element. When no voltage is applied to the solenoid coil, a compression spring or pressure in the system keeps the valve closed by pressing the sealing element against a valve seat. During operation, the flow direction of the coolant through the control valve is preferably set such that, in a closed state of the control valve, the differential pressure that builds up between an inlet and an outlet of the valve pushes the valve piston against the valve seat. To open the control valve, the valve piston must be moved by the actuator.The solenoid coil is lifted from the valve seat. The actuator therefore exerts a force against the compression spring and / or against the differential pressure applied to the sealing element. The minimum force required by the electromagnetic actuator to open the control valve depends on the spring force of the compression spring, the size of the valve seat, and / or the maximum differential pressure of the valve in the closed state. If the compression spring pushes against the fluid pressure itself, the valve unit is open in the de-energized state. These valves can be called normally-open valves or NO valves. Alternatively, the valve can be designed so that it is closed in the de-energized state. These valves can be called normally-closed valves or NC valves. In this case, the spring element and / or the differential pressure oppose the active electromagnet.The electric actuator, the solenoid coil, and / or the shape memory wire enable the control valve to be activated with a short response time. This also allows the valve in the refrigerant circuit to be controlled with a short response time.

[0012] The actuator and the control valve form a pilot control system for the valve. Pilot-operated valves require a pressure differential relative to the operating pressure to open and close. A minimum required pressure differential can be referred to as the minimum pressure. The electromagnet or actuator performs a pilot control function here, relieving the pressure on the sealing element, for example, the linear slide or a diaphragm. The coolant pressure or the existing pressure differential thus moves the sealing element and varies the flow cross-section.

[0013] The actuator and control valve can be designed as proportional valves. Proportional valves, being electromagnetic valves, can assume any intermediate position between open and closed. The proportional valve can include a proportional solenoid. A proportional solenoid is an electromagnet whose magnetic force is proportional to the applied current. This means that if the current is increased, the magnetic force also increases, and vice versa. Proportional valves can, for example, be designed as piston valves. This means that the valve element is usually an axially displaceable piston that connects or closes laterally arranged inlet and outlet ports. Other types, such as conical and disc-shaped valves, are also possible.

[0014] In one embodiment, the valve has a sealing area that seals the refrigerant circuit from the coolant circuit. In particular, the sealing area is designed to hermetically seal the refrigerant circuit from the coolant circuit. For example, the sealing area can comprise an O-ring, a lamellar seal, and / or a diaphragm. The sealing area can be arranged, for example, on the sealing element, particularly on the valve piston. Preferably, the sealing area can be arranged in the region of an end face of the valve piston. The valve piston can thus have a groove extending circumferentially. An O-ring can be arranged in this groove, sealing the refrigerant circuit from the coolant circuit. Alternatively, the lamellar seal can be arranged on an outer surface of the valve piston. Alternatively, the diaphragm can apply a control pressure to the valve and simultaneously seal it.The term "hermetic" means that no fluid exchange can occur between the coolant circuit and the refrigerant circuit. This fluidic separation prevents the coolant and refrigerant from mixing, as well as corrosion of the cylinder or other drive components, and contamination of the medium by substances such as dust or metal due to wear and tear during extended operating periods.

[0015] In one embodiment, this is a mechanical valve. In other words, the valve in the refrigerant circuit has no actuator. Preferably, the valve can be activated by the refrigerant or switched from a first state to a second state by the refrigerant. This means that the valve can preferably be designed to be pneumatically or hydraulically actuated.

[0016] In one embodiment, the valve is designed as a poppet valve or a spool valve. With poppet valves, fluid lines can be opened or closed by means of a ball element, disc element, plate element, or cone element. The valve seats are typically sealed with rubber gaskets. Poppet valves have few wear parts and therefore a long service life. Furthermore, they are resistant to dirt and robust. In spool valves, the individual ports are connected or closed by linear slides, linear flat slides, or plate slides. Linear slides are easy to operate and can be opened and closed quickly. Linear slides also exhibit good resistance to high pressures. Alternatively or additionally, in one embodiment, the control valve can be designed as a poppet valve or a spool valve.

[0017] In one embodiment, exactly one valve is assigned to the control valve, and / or at least two valves are assigned to the control valve. In other words, the control valve, or the actuator to which the control valve is assigned, can control exactly one valve. Alternatively, two or more valves can be controlled by the actuator and the control valve. For this purpose, the control valve can be operatively connected to several valves via multiple fluid channels, through which the coolant can exert a control pressure on each valve. This makes it possible to control several valves with only one actuator. In this way, space and costs can be saved.

[0018] In one embodiment, the valve is configured as a shut-off valve, a proportional valve, a mixing valve, or a diverter valve. This means that the valve unit can be used for different functions.

[0019] The shut-off valve can also be called an on / off valve. It is designed to limit the flow of refrigerant. The shut-off valve either allows unimpeded flow or completely prevents it. The shut-off valve can be used to direct the refrigerant to different points in the heat pump, to start and stop batch processes, and to activate automatic safety functions, such as shutting down the heat pump.

[0020] A proportional valve can also be called a continuous valve. Proportional valves allow for continuously variable flow rates. This enables the pressure of a fluid or refrigerant in the heat pump to be actively influenced or adjusted. In particular, the pressure can be continuously adjusted. Proportional valves can be designed as adjustable flow valves with one inlet and one outlet, or as directional control valves with more than two working ports.

[0021] In one embodiment, the valve comprises a mixing valve, or the valve can be designed as a mixing valve. In other words, the valve unit can be used to mix different refrigerant circuits or refrigerant flows. More precisely, the mixing valve can influence the ratio of two volume flows or refrigerant flows. The mixing valve can include a rotary valve. The position of the rotary valve can be adjusted via the actuator or the solenoid coil.

[0022] The diverter valve allows the distribution of the refrigerant flow within the heat pump. It can also be called a distribution valve. For example, different components of the heat pump can be supplied with refrigerant in this way. In particular, the diverter valve can be designed as a multi-way valve.

[0023] In one embodiment, the valve comprises an expansion valve. In other words, the valve can be used as an expansion valve. Preferably, the valve can reduce the pressure by a desired amount. The valve can be configured to dynamically adjust or regulate the fluid flow. The valve can thus be designed as a pressure control valve. More precisely, the valve can be configured to adjust the fluid flow by adjusting the fluid pressure. The fluid pressure can thus be directly adjusted or regulated, preferably upstream of a heat pump, particularly an evaporator.

[0024] Another aspect of the present invention relates to a valve control system for a thermal management system comprising at least one valve unit according to one of the preceding embodiments and at least one control unit for controlling the valve unit, in particular the first valve. The control unit is preferably configured to control the actuator or the actuator and the control valve. This allows the control pressure acting on the valve to be adjusted.

[0025] Another aspect of the present invention relates to a thermal management system comprising a heat pump and a cooling system, wherein the thermal management system comprises the valve unit according to one of the preceding embodiments or the valve control according to the preceding embodiment.

[0026] The heat pump is preferably designed to be supplied with a refrigerant, wherein the heat pump comprises: at least one evaporator for evaporating the refrigerant, at least one condenser for liquefying the refrigerant, a compressor unit designed to compress the refrigerant, and an expansion valve and / or a valve unit according to one of the embodiments mentioned above.

[0027] Another aspect of the present invention relates to a vehicle with the valve unit according to one of the preceding embodiments and / or the valve control according to the preceding embodiment and / or the thermal management system according to the preceding embodiment.

[0028] In one embodiment, the valve unit is designed to be compatible with a gaseous and / or a liquid fluid. For example, a liquid fluid can circulate in the coolant circuit and a gaseous fluid can circulate at least partially in the refrigerant circuit. In other words, the valve unit can be designed for both liquid and gaseous fluids. This is advantageous because, in a refrigerant circuit, the refrigerant is in a liquid or gaseous state depending on the stage of the cycle. Furthermore, it is conceivable that the refrigerant is essentially gaseous, but small amounts of liquid refrigerant remain because the refrigerant has not evaporated completely.

[0029] In one embodiment, the valve unit is signal-connected to a sensor, in particular a displacement sensor and / or a position sensor. For example, the valve unit can include a control unit that receives and processes signals from the sensor and / or transmits a manipulated variable to the valve unit, in particular to the actuator or control valve. The sensor can provide data relating to the actuator or control valve, or data relating to the valve itself. The sensor can be signal-connected to the valve unit or control unit wirelessly or via a cable. This allows the valve unit to regulate or control a fluid pressure or flow rate. The terms "regulate" or "control" can be understood as the regulation or control of a variable to be set, for example, a pressure. Regulation can, for example, maintain a setpoint or...A controller maintains a predetermined value through continuous interventions or adjustments based on measurements of an actual value or a measured value of that quantity. In other words, the controller's task is to measure a quantity to be controlled and compare it to a setpoint. In case of deviations, a manipulated variable can be changed so that the setpoint and the actual value of the quantity to be controlled match, or the difference between the two values ​​is minimized. Control is understood as a process in which a controlled variable is influenced by another variable. Deviations from the set value that occur as a result of disturbances are not detected in order to be used for correction. Control is therefore understood as a process in which an input variable influences an output variable in a device or system in a specific way.

[0030] Individual features and embodiments can be combined to form new embodiments. Further developments and effects apply analogously to these new embodiments. Features and advantages mentioned in relation to the device also apply analogously to the method, and vice versa.

[0031] The present invention is described in detail below with reference to the accompanying figures. These figures show: Fig. 1 a schematic view of an embodiment of a valve unit according to the invention.

[0032] Fig.Figure 1 shows a valve unit 10 intended for arrangement in a thermal management system. The valve unit 10 comprises a valve 11 and an actuator 12, wherein the valve 11 is arranged in a refrigerant circuit and the actuator 12 is arranged in a coolant circuit. The coolant circuit contains a coolant, for example water or a water mixture. The refrigerant circuit contains a refrigerant, for example propane.

[0033] Actuator 12 includes a control valve 13. Actuator 14 is designed to perform a linear or stroke movement. Actuator 14 includes a solenoid coil 15 or an electromagnet. The solenoid coil 15 can be connected to a voltage source or a current source that supplies actuator 12 with energy in the form of electricity.

[0034] Coaxial to the magnetic coil 15 is an armature element 16. The armature element 16 is rod-shaped. A sealing element 17 is arranged at one axial end of the armature element 16. The sealing element 17 is spherical and, in the closed state, rests against a sealing seat. The sealing seat is designed as a circular opening. The diameter of the sealing seat is selected such that it is smaller than the maximum diameter of the sealing element 17, but larger than the minimum diameter of the sealing element 17. This allows the sealing element 17 to extend partially through the sealing seat 13. Furthermore, this allows the size of the opening to be varied.

[0035] The valve 11 comprises a longitudinal slide 18. The longitudinal slide 18 includes a valve piston 19 and a sealing piston 20. The valve piston 19 is located at one axial end of the longitudinal slide 18. The valve piston 19 has a sealing area 14. The valve piston 19 is operatively connected to a control line 23. The control line is located in the coolant circuit. The control line 23 contains a coolant, for example, water or a water mixture. The coolant in the control line 23 exerts a force or pressure on the valve piston 19. This pressure can be referred to as the control pressure. Depending on the control pressure developed on the valve piston 19, the position of the longitudinal slide 18 can be varied.

[0036] The sealing piston 20 is arranged longitudinally along the longitudinal slide 18 at a distance from the valve piston 19. Here, the sealing piston 20 is located at an opposite axial end of the longitudinal slide 18. The sealing piston 20 is designed to vary a flow cross-section Q', for example, to cover it or at least partially open it. A spring element 21 is arranged at an axial end of the longitudinal slide 18. Here, the sealing piston 20 forms the axial end, and thus the spring element 21 is located on the sealing piston 20. The spring element 21 exerts a restoring force on the longitudinal slide 18. This restoring force counteracts the force exerted on the valve piston 19 by the coolant. More precisely, the restoring force counteracts the control pressure.

[0037] Control valve 13 is located in the coolant circuit. Control valve 13 is connected to a high-pressure side of the coolant circuit H' via a high-pressure line. Control valve 13 is force-transmitted to valve 11 via control line 23. More precisely, control line 23 applies the control pressure to valve 11. If the control pressure reaches a predefined value or is within a predefined pressure range, the flow cross-section Q' is varied depending on the control pressure, or at least partially opened or closed. This means that the flow cross-section Q' can be controlled depending on the control pressure.

[0038] Valve 11 is arranged in a refrigerant circuit. This means that the pressure in the refrigerant circuit can be controlled by varying the flow cross-section Q'. The flow cross-section Q' is connected to a high-pressure side of the refrigerant circuit H''. Between valve piston 19 and sealing piston 20, the longitudinal slide 18 has a smaller diameter. A free space 22 is formed between valve piston 19 and sealing piston 20 in the region of the smaller diameter. The free space 22 provides access to a low-pressure side N'' of the refrigerant circuit.

[0039] A method for using such a valve unit 10 can comprise the following steps. In a first step S1, a valve unit 10 is provided according to one of the embodiments mentioned above. In a second step S2, an actuator 12 in the coolant circuit is activated, generating a control pressure in a control line 23. Preferably, the actuator 12 is coupled to a control valve 13 in the coolant circuit. By adjusting the control valve 13, the control pressure can be generated in the control line 23. In a third step S3, the control pressure moves the valve 11 from a first position to a second position. This changes or varies the flow cross-section Q'. This means that the opening, or the size of the opening, of the flow cross-section Q' is changed. More precisely, the flow cross-section Q' can be increased or decreased.Optionally, in a fourth step S4, the actuator 12 can be controlled in such a way that the control pressure on the valve 11 is reduced to such an extent that the flow cross-section Q' of the valve 11 is completely closed.

[0040] 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. 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. Reference symbol list H' High-pressure side of the coolant circuit H'' High-pressure side of the refrigerant circuit N'' Low-pressure side of the refrigerant circuit Q' Cross-section 10 valve unit 11 valve 12 Actuator 13 Control valve 14 Sealing area 15 Magnetic coil 16 anchor elements 17 Sealing element 18 longitudinal slides 19 valve pistons 20 sealing pistons 21 Spring element 22 Free space 23 Control line

Claims

[1] Valve unit (10), in particular for arrangement in a thermal management system, comprising: a valve (11) designed to vary the flow cross-section (Q') of a refrigerant circuit, an actuator (12) designed to control the pressure of a coolant in a coolant circuit, wherein the actuator (12) is designed to apply a control pressure to the valve (11) using the coolant and wherein the valve (11) is designed to vary the flow cross-section (Q') of the refrigerant circuit depending on the control pressure. [2] Valve unit (10) according to claim 1, wherein the actuator (12) comprises a control valve (13) arranged in the coolant circuit, wherein the control valve (13) is preferably a direct-operated valve, and wherein the actuator (11) preferably comprises an electric linear actuator. [3] Valve unit (10) according to claim 1 or 2, wherein the valve (11) has a sealing area (14) that seals the refrigerant circuit against the coolant circuit. [4] Valve unit (10) according to one of the preceding claims, wherein the valve (11) is a mechanical valve. [5] Valve unit (10) according to one of the preceding claims, wherein the valve (11) is designed as a poppet valve or as a slide valve. [6] Valve unit (10) according to one of the preceding claims, wherein exactly one valve (11) is assigned to the control valve (13) and / or at least two valves (11) are assigned to the control valve (13). [7] Valve unit (10) according to one of the preceding claims, wherein the valve (11) is configured as a shut-off valve or as a proportional valve or as a mixing valve or as a switching valve. [8] Valve control for a thermal management system comprising at least one valve unit (10) according to one of the preceding claims and at least one control unit for controlling the valve unit (10), in particular the control valve (13). [9] Thermal management system comprising a heat pump and a cooling system, wherein the thermal management system comprises a valve unit (10) according to any one of claims 1 to 7 or a valve control according to claim 8. [10] Vehicle with a valve unit (10) according to any one of claims 1 to 7 and / or a valve control according to claim 8 and / or a thermal management system according to claim 9.

Images