Method for operating temperature control system, computing unit and computer program

Abstract

The invention relates to a method for operating a temperature control system, comprising a refrigerant circuit having a compressor, a first heat exchanger for transferring heat from a first component to be temperature-controlled to the refrigerant circuit, and a second heat exchanger for transferring heat from a second component to be temperature-controlled to the refrigerant circuit. A second heat exchanger for transferring heat from a second component to be conditioned to the refrigerant circuit includes: supplying a first mass flow of refrigerant to the first heat exchanger according to a first temperature preset with respect to the first component and a current temperature of the first component; receiving a second temperature preset with respect to the first component during the supply of the first mass flow, the second temperature preset including a target temperature higher than the first temperature preset; the compression power of the adaptive compressor is preset based on the second temperature; and reducing or stopping the supply of the first mass flow to the first heat exchanger and increasing the supply of refrigerant of the second mass flow to the second heat exchanger until the temperature of the refrigerant has been raised to a target temperature level required to meet the second temperature presetting.

Description

Technical Field

[0001] The invention relates to a method for operating a temperature control system, as well as a computing unit and a computer program for carrying out the method. Background Art

[0002] A refrigerant circuit can be used in a temperature control system, particularly for cooling the passenger compartment of a vehicle. When the cooling demand increases (e.g., by setting a lower target temperature), the target value for the evaporation temperature (which typically corresponds to a pressure level in the refrigerant circuit) can be set to a lower level. Deviations between the current evaporation temperature and the new target value can be compensated for by using the refrigerant compressor in the temperature control system or by increasing the compressor's rotational speed. Before reaching the reduced pressure level on the suction side of the compressor, the cooling capacity of the refrigerant circuit typically decreases, and the passenger compartment cooling may fall below the desired level.

[0003] The other approach can be problematic if cabin cooling is reduced (e.g., by setting a higher target temperature). For example, if the target cabin temperature is increased, the HVAC system (heating, ventilation, and air conditioning) is typically increased, for example, to the target evaporation temperature and the cabin fan speed is reduced. However, a rapid reduction in cabin fan speed can also be the sole cause. However, the refrigerant is still at a relatively low temperature, and the heat exchange between the refrigerant and the cabin (due to the reduced circulation of cabin air caused by the reduced fan speed) is also drastically reduced. This results in no or significantly delayed refrigerant evaporation. This leads to no refrigerant evaporation and, consequently, to excessively low pressure or temperature at the compressor inlet and a reduction in compressor speed, which can cause the system to completely shut down the refrigerant compressor. A second effect can be closing the expansion valve due to insufficient evaporation, thereby reducing mass flow. This system state persists for a relatively long time and poses significant problems with stability and maintaining system operation. The shut-off of the compressor can be combined with a predetermined shut-off time in order to achieve a uniform pressure level in the system on the one hand and to avoid repeated switching on and off of the compressor (which is detrimental to the life of the compressor) on the other hand. In terms of power, this system state is particularly demanding. Summary of the Invention

[0004] According to the invention, a method for operating a temperature control system with two heat exchangers, as well as a computing unit and a computer program for carrying out the method are proposed, having the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims and the following description.

[0005] The measure used in the present invention is that when changing the temperature preset for a first component to be temperature-controlled by a temperature control system (such a change causes a reduction in the cooling power required by the first component), the refrigerant is temporarily at least partially supplied to the heat exchanger for temperature-controlling a second component. Thereby, on the one hand, the changed desired temperature in, for example, the passenger compartment of a vehicle can be quickly set according to the temperature preset, and on the other hand, the temperature control system and especially its compressor remain activated and are thus well controllable. Thereby, a more favorable time load distribution in terms of the durability of the temperature control system can also be achieved. By using the diversion of the refrigerant for temperature-controlling the second component, the thermal mass of the second component can be used as a temporary thermal buffer so that the refrigerant can be quickly set to a new temperature level. In particular, the traction battery of an at least partially electrically driven vehicle or its temperature control medium circuit is suitable as such a second component due to its usually large mass and heat capacity. In addition, the traction battery or its temperature control medium circuit is usually already equipped with a heat exchanger, so that only few structural changes are required to implement the present invention.

[0006] In the framework of the present invention, a usable temperature control system includes a refrigerant circuit having a compressor and at least a first heat exchanger and a second heat exchanger, the first heat exchanger being configured to transfer heat from a first component to be temperature-controlled to the refrigerant circuit, and the second heat exchanger being configured to transfer heat from a second component to be temperature-controlled to the refrigerant circuit.

[0007] Specifically, the method according to the present invention includes: supplying a first mass flow of refrigerant to the first heat exchanger according to a first temperature preset for the first component and the current temperature of the first component; receiving a second temperature preset for the first component during the supply of the first mass flow, wherein the second temperature preset includes a target temperature higher than the first temperature preset; adapting the compression power of the compressor based on the second temperature preset; and reducing or stopping the supply of the first mass flow to the first heat exchanger and increasing the supply of the second mass flow of refrigerant to the second heat exchanger until the temperature of the refrigerant has been heated to the target temperature level required for meeting the second temperature preset.

[0008] In the framework of the present invention, "refrigerant" is understood as a temperature control medium that undergoes a phase change (such as condensation, evaporation,...) at least in some operating states of the temperature control system. For example, hydrocarbons (such as ethane, propane, butane or their derivatives and their mixtures), ammonia and / or carbon dioxide can be used as the refrigerant.

[0009] In at least one design, the second mass flow increases by an amount corresponding to the magnitude of the first mass flow or by an amount greater than 30%, greater than 50%, greater than 70% or greater than 80% of the magnitude of the first mass flow. Thus, the refrigerant can be quickly heated to the required higher target temperature level without having to operate the compressor in an unfavorable operating state.

[0010] In at least one design, the thermal mass of the second component (defined as the product of mass and specific heat capacity) exceeds the thermal mass of the first component, in particular by more than 25%, more than 50% or more than 100%. As already mentioned, it is advantageous to use the second component as a thermal buffer. The higher the thermal mass of the second component, the better it works, because even if the second component absorbs or outputs more heat, the temperature of the second component only changes less.

[0011] In at least one design, the first component includes the passenger compartment of the vehicle and / or the second component includes the battery of the electric vehicle. As already explained at the beginning, this is a particularly relevant and technically advantageous application case, because on the one hand the battery of the vehicle usually has a high mass and thus also a high heat capacity, and on the other hand also has a temperature level that is usually relatively stable and often higher than the desired passenger compartment temperature (first temperature preset and / or second temperature preset), which is advantageous for the heating of the refrigerant to be achieved.

[0012] In at least one design, the method includes: after adapting the compression power of the compressor, when the temperature of the refrigerant on the pressure side of the compressor has reached the target temperature level, supplying the refrigerant of the third mass flow to the first heat exchanger according to the second temperature preset and the current temperature of the first component. In other words, within the framework of the method, once the refrigerant has been sufficiently heated, the temperature can be set according to the second temperature preset.

[0013] Here, the method can particularly include, after adapting the compression power of the compressor: reducing the mass flow of the refrigerant supplied to the second component to a fourth mass flow, which corresponds to the magnitude of the second mass flow or is less than the second mass flow. Since the heating by means of heat absorption from the second component has ended in this case, the second component can be re-tempered according to its own heat requirements, which will generally include less cooling than before the method was carried out, because the second component was temporarily cooled more strongly than would actually be required from the perspective of the second component. Therefore, the amount of refrigerant supplied to the second component (or the second heat exchanger) can be at least temporarily reduced below the original value.

[0014] In at least one design, the second mass flow can be selected based on the target temperature and / or the current temperature of the second component and / or, if carried out as described above, the fourth mass flow can also be selected. Thereby, it is possible to set or control the temperature of the second component essentially independently of the temperature preset for the first component outside the transition period described here, during which the temperature preset is changed and thus a new temperature level of the refrigerant must be set. During the temperature adaptation of the refrigerant, for example, the temperature regulation for the second component can be deactivated, and this temperature regulation can then be reactivated after the temperature adaptation. Generally, since the traction battery has a very high heat capacity or thermal mass as already explained, the temperature change in the traction battery caused by this temporarily increased cooling power is negligibly small. Instead of deactivating the temperature regulation of the second component, the corresponding temperature target value can also be adapted to cause a higher mass flow of the refrigerant to be directed to the second heat exchanger.

[0015] In at least one design, the method further includes obtaining the current temperature of the first component and / or the current temperature of the second component, wherein the obtaining is carried out in particular in the case of using one or more sensors and / or in the case of using a thermal model of the temperature control system and / or the first component and / or the second component. This enables precise control of the respectively required target temperature.

[0016] The computing unit according to the invention, for example, the controller of a motor vehicle, is in particular set up in terms of program technology to carry out the method according to the invention.

[0017] An implementation in the form of a computer program or a computer program product according to the method of the invention, having program code for carrying out all method steps, is also advantageous because this results in particularly low costs, especially if the controller to be implemented is also used for other purposes and thus already exists. Finally, a machine-readable storage medium is provided, which has stored thereon the computer program as described above. Suitable storage media or data carriers for providing the computer program are in particular magnetic, optical, and electrical memories, such as, for example, hard disks, flash memories, EEPROMs, DVDs, etc. Downloading the program via a computer network (Internet, intranet, etc.) is also possible. Such a download can be carried out here either wired or wired-connected or wirelessly (e.g., via a WLAN network, 3G-, 4G-, 5G-, or 6G- connection, etc.).

[0018] Further advantages and designs of the invention result from the description and the drawings.

[0019] The invention is schematically illustrated in the embodiments in the drawings and is described below with reference to the drawings. Description of the Drawings

[0020] Figure 1 A temperature control system that can be used in the design of the present invention is schematically shown according to a simplified block diagram.

[0021] Figure 2 A design of the method according to the present invention is schematically shown according to a simplified flowchart. Detailed implementation manners

[0022] In Figure 1 a temperature control system that can be used in the design of the present invention is schematically shown according to a block diagram and is generally designated by 100. In the example shown here, the temperature control system 100 is part of a vehicle and includes a refrigerant circuit 13 that has a compressor 130 for compressing the refrigerant included in the refrigerant circuit and has at least one first heat exchanger 142 and at least one second heat exchanger 112. The mass flow distribution of the refrigerant to the two heat exchangers 142, 112 can be achieved by means of valves 114, 144.

[0023] The first heat exchanger 142 is configured to transfer heat from a first component 140 to be temperature-controlled, which in the example shown here includes the vehicle passenger compartment, to the refrigerant circuit 13 (or the refrigerant). A temperature preset for the vehicle passenger compartment 140 can be input, for example, by means of an operating element 146.

[0024] The second heat exchanger 112 is configured to transfer heat from a second component 110 to be temperature-controlled, which here particularly includes the vehicle battery, to the refrigerant circuit 13. The battery 110 is here configured to supply electrical energy to an electric motor 150 for driving the vehicle wheels 160 and to store electrical energy generated by the electric motor 150 (for example, in a regenerative mode).

[0025] The second component 110 to be temperature-controlled can also include a temperature control medium circuit that transports heat between the heat exchanger 112 and, for example, a battery having a cooling body traversed by the temperature control medium. Similarly, the first component 140 (passenger compartment) can also include a temperature control medium circuit for transferring heat to or from the refrigerant circuit 13.

[0026] In the example shown here, sensors 132, 134 are respectively provided upstream (suction side) and downstream (pressure side) of the compressor 130, and these sensors can be used to monitor or control the operation of the compressor 130. In particular, pressure- and / or temperature sensors can be used as sensors 132, 134.

[0027] The computing unit 120, such as the controller of a vehicle or in particular the controller of the temperature control system 100, is connected to the operating unit 146 and the sensors 132, 134 in a data-receiving manner in order to monitor the operation of the temperature control system 100, in particular the compressor 130. Furthermore, the computing unit 120 is connected to the compressor 130 and the valves 114, 144 in a data-conducting manner in order to control them. Alternatively, the valve 144 that regulates the mass flow into the first heat exchanger 142 can be implemented self-regulating (e.g., a thermally controlled expansion valve). In such cases, a data-conducting connection from the computing unit 120 to the valve 144 is not required.

[0028] The temperature control system 100 can also include further components, in particular for example one or more heat exchangers and / or further valves, which are, however, neither shown nor discussed here for reasons of clarity.

[0029] The following describes, for example, how such a control can be run in the case of referring to Figure 2 in which a design of the method according to the invention is schematically shown according to a simplified flow diagram and is generally designated by 200. Here, the reference to the device components can be understood in particular with respect to Figure 2 Figure 1 the temperature control system 100 shown in, and other suitable temperature control systems can also be used to perform the method 200, so that the reference to Figure 1 is not restrictive in this regard at all.

[0030] When the first component 140 needs to be cooled, the method 200 is particularly used.

[0031] In the framework of the method 200, a temperature preset is received in a first step 210. This can be achieved, for example, by transmitting the setting at the operating element 146 to the computing unit 120 or by the computing unit 120 reading it.

[0032] Furthermore, in step 220, the current temperature of the first component 140 to be temperature-controlled is obtained, for example, in the case of using sensors and / or in the case of using a temperature model of the first component 140. In order to obtain the temperature of the first component 140 (i.e., the vehicle passenger compartment here), the temperature of the refrigerant can also be used in particular, and this temperature can be obtained in the case of using the sensors 132, 134.

[0033] ​In step 230, it is checked here whether the temperature preset received in this way has changed relative to the previously received temperature preset such that a higher target temperature for the first component 140 (vehicle passenger compartment) to be temperature-controlled results therefrom. If this is not the case (i.e., the temperature preset remains constant or the target temperature decreases; "first temperature preset" 232), the method 200 is continued with step 240.

[0034] In step 240, the temperature control system 100 is operated in accordance with the first temperature preset 232 and based on the current temperature obtained in step 220 such that the current temperature approaches the target temperature according to the first temperature preset. Here, the compression power of the compressor 130 and the position of the valve 114 (which supplies the refrigerant to the second heat exchanger 112) and the position of the valve 144 (which supplies the refrigerant to the first heat exchanger 142) are controlled such that a first mass flow of refrigerant is supplied to the first heat exchanger 142. The first mass flow is measured here such that the cooling power generated in the first heat exchanger 142 quickly and precisely sets the target temperature desired for the first component 140 according to the first temperature preset 232.

[0035] If, conversely, it is determined in step 230 that the temperature preset has changed such that a higher target temperature than hitherto results, i.e., less cooling power must be provided from the side of the temperature control system 100 compared to the previous period ("second temperature preset" 234), the method 200 is continued with step 250. Here, a difference threshold for the minimum required difference between the first temperature preset and the second temperature preset can be set in particular, such that the method does not switch to step 250 with every increase in the target temperature, but only if the difference threshold is exceeded.

[0036] In step 250, the supply of refrigerant to the first heat exchanger 142 is reduced or completely stopped in order to achieve the less cooling power required according to the second temperature preset. In order to reduce the mass flow supplied to the first heat exchanger, for example, the opening degree of the valve 144 can be reduced or the valve 144 can be completely closed. In particular, in a design of the valve 144 as a thermostatic expansion valve (TXV), this can be done automatically when adapting the temperature preset.

[0037] At least a part of the refrigerant that is no longer supplied to the first heat exchanger 142 is hereby supplied to the second heat exchanger 112 in order to be heated there. For this purpose, the valve 114 can be (further) opened. This means that, compared to the refrigerant that would be required for the temperature regulation of the second assembly 110, more refrigerant is supplied to the second heat exchanger 112 during this operating phase (during adaptation to the second temperature preset). In other words, the temperature regulation of the second assembly 110 is interrupted during this transition phase, and the valve 114 is controlled bypassing the regulator. The valve 114 can be provided, for example, in the form of a thermal expansion valve or an electronic expansion valve, and other suitable valve types can also be used. In the case where a thermal expansion valve is used as the valve 114, for example, the thermal power can be adjusted by means of a bypass valve for the second heat exchanger in the water section. That is to say, in this case, the thermal power is increased by guiding more cooling water through the heat exchanger and thus (by means of the corresponding regulator) opening the valve 114 and thus allowing more refrigerant to pass through.

[0038] Even without changing the opening degree of the valve 114 (which limits the refrigerant inflow to the second heat exchanger 112), a higher mass flow to the second heat exchanger 112 is set in the case of a reduced opening degree of the valve 144 in the refrigerant path leading to the first heat exchanger 142. Due to the higher mass flow in the second heat exchanger 112, the refrigerant is heated more quickly in order to achieve a higher refrigerant temperature or the required refrigerant pressure at the suction side of the compressor 130 for setting the new target temperature.

[0039] As an alternative or addition to the options already mentioned, the mass flow of the refrigerant through the second heat exchanger 112 can be set by appropriately activating or increasing the power of a refrigerant pump or a temperature control medium pump (not shown separately in the figures) in the refrigerant path or the temperature control medium path including the second heat exchanger 112, as already mentioned. As an alternative or addition, a valve (such as an electronic control valve, etc.) in the temperature control medium path of the battery (for example, such a temperature control medium with respect to which the refrigerant in the second heat exchanger 112 is heated) can also be (further) opened in order to increase the heat exchange capacity of the second heat exchanger. Here, regardless of the specific combination of the measures explained here, the second assembly (here the battery) 110 is cooled more intensively compared to the cooling that would actually be required for operating the second assembly 110.

[0040] In other words, the second component 110 serves as a heat accumulator during step 250. In the example shown here, this is particularly advantageous because the compressor 130 remains in operation and can ensure the evaporation of the refrigerant. Thereby, cycling (repeated switching on and off) of the compressor 130 is avoided, the time to reach the new target temperature is shortened, and the compressor control can be calibrated in terms of a slower and thus acoustically less perceptible transition. Due to the high thermal mass of the battery 110, this brief cooling of the battery 110 during the transition phase (step 250) does not significantly affect the battery temperature itself.

[0041] In step 260, it is checked whether the current temperature obtained in step 220 or the current temperature of the refrigerant has increased to the temperature required according to the second temperature preset. If this is the case, the method 200 returns to steps 210, 220 (and thus waits for a new change in the temperature preset), whereupon the compression power and / or the valve position are set according to the second temperature preset. If, conversely, it is determined in step 260 that the required temperature increase (or the required target temperature level) has not yet been reached, the method 200 is continued in step 250 for as long as the temperature increase is sufficient.

[0042] In an alternative design, instead of the check in step 260, the cooling time and increase of the second component 110 (within the framework of step 250) can be constant. In particularly demanding variants, the required degree of cooling of the second component 110 can be estimated based on the thermal energy required to convert the refrigerant temperature to the new target value (the target temperature level according to the second temperature preset 234).

[0043] It is to be expressly emphasized here that, for reasons of better understanding only, the step-by-step processing described within the framework of the method 200 is explained here as an example. However, in the design of the present invention, a design of the method 200 deviating from these processing methods can also be selected, where the steps can in particular be performed in other, for example, reverse orders or partly or completely in parallel or simultaneously with respect to each other. In the design of the present invention, partial or complete continuous or periodic repetition of individual or all steps can also be provided.

Claims

1. A method (200) for operating a temperature control system (100), the temperature control system comprising a refrigerant circuit (13) having a compressor (130) and at least a first heat exchanger (142) and a second heat exchanger (112), the first heat exchanger being configured to transfer heat from a first component (140) to be temperature-controlled to the refrigerant circuit (13), and the second heat exchanger being configured to transfer heat from a second component (110) to be temperature-controlled to the refrigerant circuit (13). Among them, The method (200) comprises: Supplying (240) a first mass flow of refrigerant to the first heat exchanger (142) in accordance with a first temperature preset (232) for the first component (140) and a current temperature (220) of the first component (140); Receiving (210) a second temperature preset (234) for the first component (140) during the supply (240) of the first mass flow, wherein the second temperature preset (234) comprises a target temperature (230) higher than the first temperature preset (232); Adapting the compression power of the compressor (130) based on the second temperature preset (234); and Reducing or stopping (250) the supply of the first mass flow to the first heat exchanger (142) and increasing the supply of a second mass flow of refrigerant to the second heat exchanger (112) until the temperature of the refrigerant has been heated (260) to a target temperature level required to meet the second temperature preset.

2. The method (200) according to claim 1, wherein The second mass flow is increased by an amount corresponding to the magnitude of the first mass flow or by an amount greater than 30%, greater than 50%, greater than 70% or greater than 80% of the magnitude of the first mass flow.

3. The method (200) according to claim 1 or 2, wherein, The thermal mass of the second component (110) exceeds the thermal mass of the first component (140), in particular by more than 25%, more than 50% or more than 100%.

4. The method (200) according to any one of the preceding claims, wherein: The first component (140) comprises the passenger compartment of a vehicle, and / or the second component (110) comprises a battery and / or components of a drive train (150) of an electric vehicle.

5. The method (200) according to any one of the preceding claims, wherein, The method comprises: after adapting the compression power of the compressor (130), when the temperature of the refrigerant has reached (260) the target temperature level, supplying a third mass flow of refrigerant to the first heat exchanger (142) according to the second temperature preset (234) and the current temperature (220) of the first component (140).

6. The method (200) according to claim 5, after adapting the compression power of the compressor (130), includes: Reducing the mass flow of refrigerant supplied to the second heat exchanger (112) to a fourth mass flow corresponding to or less than the magnitude of the second mass flow.

7. The method (200) according to any one of the preceding claims, wherein, Selecting the second mass flow according to the target temperature and / or the current temperature of the second component (110) and / or selecting the fourth mass flow if according to claim 6.

8. The method (200) according to any one of the preceding claims, comprising obtaining the current temperature (220) of the first component (140) and / or the current temperature of the second component (110), wherein, The acquisition is carried out especially in the case of using one or more sensors (132, 134) and / or in the case of using the thermal model of the temperature control system (100) and / or of the first component (140) and / or the second component (110).

9. A computing unit (120), which is set up to carry out all method steps of the method (200) according to any one of the preceding claims.

10. A computer program, which, when implemented on a computing unit (120), causes the computing unit (120) to carry out all method steps of the method (200) according to any one of claims 1 to 8.

11. A machine-readable storage medium, having stored thereon the computer program according to claim 10.

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