Methods for controlling an air conditioning system and air conditioning

Abstract

Method for controlling an air conditioning system (1) comprising a refrigerant circuit with at least one evaporator (2) and a heating circuit (4) fluidly connected to a coolant circuit (3) with at least one heating heat exchanger (5), comprising at least the following steps: - Charging the heating circuit (4) used as a cold storage unit with cold when it is determined that cooling capacity is required and the refrigerant circuit is in operation and the temperature of the refrigerant circuit and / or the evaporator (2) is lower than the temperature of the heating circuit (4) and / or the heating heat exchanger (5), then disconnecting the heating circuit (4) from the coolant circuit (3) and subsequently connecting a fluid storage tank (11) to the heating circuit (4) and circulating the fluid contained in the heating circuit (4), the heating heat exchanger (5) and the fluid storage tank (11) by means of a fluid pump (12) contained in the heating circuit (4), then supplying at least a portion of the air (14) flowing through and cooled by the evaporator (2) to the heating heat exchanger (5), and switching off the fluid pump (12) when it is determined thatthat the temperature of the refrigerant circuit and / or the evaporator (2) is no longer lower than the temperature of the heating circuit (4) and / or the heating heat exchanger (5), , - Discharging the heating circuit (4) used as a cold storage unit, i.e., the cold stored in the heating circuit (4), and cooling the air (17) flowing through the heat exchanger (5) when it is determined that cooling capacity is required and the refrigerant circuit is not in operation and the temperature of the heating circuit (4) and / or the heat exchanger (5) is lower than the temperature of the refrigerant circuit and / or the evaporator (2), then disconnecting the heating circuit (4) from the coolant circuit (3) and subsequently connecting the fluid storage tank (11) to the heating circuit (4) by means of a fluid-conducting flow and circulating the fluid contained in the heating circuit (4), the heat exchanger (5) and the fluid storage tank (11) by means of the fluid pump (12), then supplying at least a portion of the air (14) flowing through and cooled by the evaporator (2) to the heat exchanger (5),wherein the proportion of air (17) flowing through the heating heat exchanger (5) is increased with increasing temperature of the evaporator (2) and / or the refrigerant circuit, and stopping the circulation of the fluid by switching off the fluid pump (12) when it is determined that the temperature of the heating circuit (4) and / or the heating heat exchanger (5) is no longer lower than the temperature of the refrigerant circuit and / or the evaporator (2).

Description

[0001] The present invention relates to a method for controlling an air conditioning system and an air conditioning system.

[0002] In a vehicle equipped with a so-called start-stop system, the engine that powers the vehicle's propulsion is automatically and temporarily stopped or switched off when no drive energy is required, for example, when waiting at a traffic light. Particularly in urban traffic, such start-stop systems contribute significantly to reducing fuel consumption. Therefore, they are now standard equipment in both conventional vehicles and, for example, in low-energy vehicles, hybrid vehicles, and the like.

[0003] If the vehicle's engine also provides the drive energy for an air conditioning system's refrigerant circuit, as is generally the case—for example, by driving a compressor of a compression refrigeration circuit via a belt drive—then automatically switching off the vehicle's engine means that the compressor of the air conditioning system's refrigerant circuit, and thus the entire refrigerant circuit, is also temporarily deactivated. When the compressor switches off, the temperature of the evaporator, which acts as the air exchanger in the air conditioning system, increases. Consequently, when the engine is off, the air being cooled by the refrigerant circuit, which is supplied to a passenger compartment, for example, becomes warmer, thus reducing comfort.

[0004] To solve this problem, various designs for air conditioning systems have already been proposed. For example, DE 101 24 757 A1 relates to a vehicle air conditioning system in which a cold storage unit is arranged between the downstream side of a cooling heat exchanger and the upstream side of an air mixing flap, so that it can be cooled by the cold air passing through the cooling heat exchanger. The cold storage unit can thus be cooled by the cold air from the cooling heat exchanger, and it is also located on the upstream side of the air mixing flap and can be cooled without being affected by the rotational position of the air mixing flap.

[0005] Furthermore, DE 103 17 039 A1 discloses a device for regulating the air supply with an evaporator and a heating element, wherein an airflow is divided into at least two air ducts. A first air duct directs the corresponding first partial airflow through the evaporator and the heating element, and a second air duct directs the corresponding second partial airflow past the evaporator and the heating element. In addition, the use of such a device in an air conditioning system in a motor vehicle is proposed.

[0006] DE 697 38 026 T2 relates to a vehicle air conditioning system and describes how the compressor could be driven by the electric motor's drive force, provided that the load on the drive shaft is reduced by the load-reducing device when the internal combustion engine is stopped. In this case, it would not be necessary to provide a drive unit used solely for driving the compressor, nor would it be necessary to start the brake motor to drive the compressor.

[0007] Furthermore, DE 102 48 773 B4 describes an air conditioning system for a motor vehicle whose drive engine is switched off during short-term standstills to save energy, in accordance with a stop-and-go function. The air conditioning system has a compression refrigeration circuit driven by the drive engine and at least one short-term cold storage unit that can be charged with cold via the compression refrigeration circuit. This short-term cold storage unit is specifically designed to be discharged when the drive engine is switched off due to a short-term standstill of the motor vehicle. In this operating state, the air conditioning system automatically switches to a recirculation mode, with at least one short-term cold storage unit being arranged in at least one recirculation duct.

[0008] Against this background, the present invention aims to provide an improved method for controlling an air conditioning system, and an improved air conditioning system, in particular a heating and air conditioning system (HVAC) for a motor vehicle with a start-stop system.

[0009] The problem is solved by a method for controlling an air conditioning system with the features of claim 1. A method for controlling an air conditioning system is presented, which has a refrigerant circuit with at least one evaporator and a heating circuit fluidly connected to a coolant circuit with at least one heat exchanger, comprising at least the following steps:

[0010] Charging the heating circuit used as a cold storage unit with cold when it is determined that cooling capacity is required and the refrigerant circuit is in operation and the temperature of the refrigerant circuit or the evaporator is lower than the temperature of the heating circuit and / or the heat exchanger; then disconnecting the heating circuit from the coolant circuit and subsequently connecting a fluid storage tank to the heating circuit and circulating the fluid contained in the heating circuit, the heat exchanger and the fluid storage tank by means of a fluid pump located in the heating circuit; then supplying at least a portion of the air flowing through and cooled by the evaporator to the heat exchanger, and switching off the fluid pump when it is determined that the temperature of the refrigerant circuit or the heat exchanger is lower than the temperature of the heating circuit and / or the heat exchanger.the temperature of the evaporator is no longer lower than the temperature of the heating circuit and / or the heating heat exchanger.

[0011] Discharging the heating circuit used as a cold storage system, i.e., the cold stored in the heating circuit, and cooling the air flowing through the heat exchanger when it is determined that cooling capacity is required and the refrigerant circuit is not in operation and the temperature of the heating circuit and / or the heat exchanger is lower than the temperature of the refrigerant circuit and / or the evaporator, then disconnecting the heating circuit from the coolant circuit and subsequently connecting the fluid storage tank to the heating circuit and circulating the fluid contained in the heating circuit, the heat exchanger and the fluid storage tank by means of the fluid pump, then supplying at least a portion of the air flowing through the evaporator and cooled by it to the heat exchanger.wherein the proportion of air flowing through the heating heat exchanger increases with increasing temperature of the evaporator and / or the refrigerant circuit, and stopping the circulation of the fluid by switching off the fluid pump when it is determined that the temperature of the heating circuit and / or the heating heat exchanger is no longer lower than the temperature of the refrigerant circuit and / or the evaporator.

[0012] Further, particularly advantageous embodiments of the invention are disclosed in the dependent claims.

[0013] The solution to the apparatus-related part of the problem is achieved with an air conditioning system having the features of claim 8, wherein an air conditioning system is shown which has a refrigerant circuit with at least one evaporator and a heating circuit with at least one heat exchanger fluidly connected to a coolant circuit, and which has a control system for carrying out the method according to the invention.

[0014] It should be noted that the features listed individually in the patent claims can be combined with one another in any technically meaningful way and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0015] The method according to the invention offers the significant advantage that, by using the heating circuit as a cold storage medium, an additional cold storage medium for providing a (temporary) cold storage function can be dispensed with. According to the invention, only the assemblies or components typically installed in an air conditioning system, in particular a heating and air conditioning system (HVAC), are used, so that no additional components, which would result in an increase in weight, are required to provide the cold storage function. Furthermore, retrofitting existing air conditioning systems without a cold storage function can also be implemented in a particularly simple and cost-effective manner using the method according to the invention, since the existing components of the air conditioning system only need to be controlled according to the method according to the invention.

[0016] The heating circuit and / or cold storage unit is only charged and discharged when the air conditioning system is required to provide cooling. This occurs, for example, when the target cooling temperature, such as that of a vehicle's passenger compartment, is lower than the actual cooling temperature. This limits the additional load on the air conditioning system, required to charge the heating circuit used as a cold storage unit, to those times when the cold storage function is actually needed – namely, when the air conditioning system is being used for cooling. This ensures particularly energy-efficient operation of the air conditioning system despite the additional cold storage function.

[0017] In an advantageous embodiment of the invention, during the charging and / or discharging steps, at least a portion of the air flowing through the evaporator is directed to the heat exchanger by means of an airflow control device, for example, a temperature control flap. Advantageously, the airflow control device is designed to continuously control the proportion of air supplied to the heat exchanger relative to the total air flowing through the evaporator within a range of approximately 0% to approximately 100%. The portion of air not supplied to the heat exchanger is bypassed by the airflow control device and is, for example, directly available for cooling a passenger compartment of a motor vehicle.

[0018] By distributing the airflow in this way, it is possible, for example, during the charging phase, to circulate air cooled by the evaporator through the heat exchanger, thus cooling it and the fluid contained within it and in the heating circuit. Furthermore, it is always ensured that sufficient cooling capacity is available, for example, for cooling the passenger compartment. During the discharging phase, the amount of cooling transferred from the heating circuit to the air flowing through the heat exchanger, and thus the cooling capacity provided by the heating circuit operating as a cold storage unit, can also be controlled.

[0019] Preferably, the amount of air supplied to the heating heat exchanger during the charging and / or discharging phases is controlled by an airflow control device, depending on the temperature difference between the refrigerant circuit or evaporator and the heating circuit or heating heat exchanger. Preferably, during the charging phase, the amount of air supplied to the heating heat exchanger is increased by the airflow control device the lower the temperature of the evaporator or refrigerant circuit is compared to the temperature of the heating heat exchanger or heating circuit, i.e., the greater the absolute temperature difference between these circuits. This ensures that the heating circuit, used as a cold storage unit, is charged with cold as quickly as possible.

[0020] During the discharge phase, the airflow control device preferably increases the volume of air supplied to the heating heat exchanger. In this case, however, the increase is proportional to the temperature of the evaporator or refrigerant circuit compared to the temperature of the heating heat exchanger or heating circuit, i.e., the greater the absolute temperature difference between these circuits. This enables optimal cold storage operation with regard to energy utilization and energy storage, since after the refrigerant circuit is switched off, the residual cold stored in it is initially used to cool the air flowing through the evaporator. In this way, only the amount of cold required to further cool the air to a predetermined target cooling temperature is drawn from the heating circuit.

[0021] In a further advantageous embodiment of the invention, the charging and / or discharging step comprises separating the heating circuit from the coolant circuit by means of a controllable valve, for example a flow control valve, which is closed during the charging and / or discharging step. By separating the heating circuit from the coolant circuit, in particular a coolant circuit of a motor vehicle engine, only the heating circuit, the heat exchanger, and the fluid contained in the heating circuit are used as a cold storage medium. The coolant circuit, which is otherwise fluidly connected to the heating circuit, is not affected by the cold storage function.On the one hand, this allows the same fluid to be used for both the coolant circuit and the heating circuit, so that when the heating circuit is not being used as a cold storage unit (which is usually the case when no cooling capacity is required from the air conditioning system), it can be used to provide heat by means of the fluid circulating in the coolant circuit, which is heated, for example, by a vehicle engine. On the other hand, the fluid contained in the heating circuit can be used entirely for cold storage, thus achieving a high cold storage capacity for the heating circuit.An undesirable, adverse influence of the fluid circulating in the coolant circuit, which is usually heated by the vehicle engine, is avoided by separating the two circuits from each other using the controllable valve, thereby ensuring optimal cold storage capacity from the heating circuit.

[0022] According to an advantageous embodiment of the invention, the charging and / or discharging step comprises connecting at least one fluid storage container to the heating circuit via a controllable valve, for example, a flow control valve, which is opened during the charging and / or discharging step. Providing and connecting at least one fluid storage container to the heating circuit increases the amount of fluid available for cold storage in the heating circuit and thus the available cold storage capacity of the heating circuit. In general, an increase in the amount of fluid in the heating circuit leads to a greater cooling capacity of the heating circuit due to the larger storage capacity; however, it also increases the time required to fully charge the cold storage container.

[0023] Selecting at least one fluid storage tank with a sufficiently large volume makes it particularly easy to adapt the storage capacity of the heating circuit used as a cold storage unit to the given operating conditions of the air conditioning system. Even during operation, dynamic capacity adjustment is possible by connecting or disconnecting one or more storage tanks using a controllable valve. For example, when cooling demand is high, such as during high outside temperatures or city driving with numerous stops, the cold storage capacity could be increased to ensure passenger comfort. Conversely, when cooling demand is low, such as during lower outside temperatures or highway driving, the storage capacity could be reduced, allowing the air conditioning system to operate more energy-efficiently.

[0024] Advantageously, at least one fluid storage tank is designed in such a way that the thermal losses of the fluid stored in it are as low as possible. For example, the fluid storage tank is equipped with suitable heat or cold insulation.

[0025] Both the separation of the heating circuit from the coolant circuit and the connection of at least one fluid storage tank to the heating circuit are accomplished using a single controllable valve, for example, a multi-way control valve. This simplifies both the design of the air conditioning system and its control, as only one valve needs to be installed and controlled.

[0026] As mentioned, the charging and / or discharging process involves circulating the fluid in the heating circuit using a fluid pump located within the circuit. This circulation ensures that all of the fluid in the heating circuit, and not just the fluid in the heat exchanger, is available for cold storage. This allows for a simple increase in cold storage capacity by utilizing the entire volume of fluid in the heating circuit.

[0027] During the charging step, the fluid pump is activated if it is determined that the temperature of the refrigerant circuit or the evaporator is lower than the temperature of the heating circuit or the heating heat exchanger; otherwise, the fluid pump is deactivated. Similarly, during the discharging step, the fluid pump is activated if it is determined that the temperature of the heating circuit or the heating heat exchanger is lower than the temperature of the refrigerant circuit or the evaporator; otherwise, the fluid pump is deactivated.This enables optimal operation of the air conditioning system, as the fluid in the heating circuit is circulated by the fluid pump only during the charging phase, as long as the fluid's cold storage capacity is not yet exhausted, and / or during the discharging phase, the fluid is circulated by the fluid pump only as long as the cold stored in the fluid can still be used to cool the air flowing through the heat exchanger. In all other cases, the fluid pump is deactivated, i.e., switched off, and the air conditioning system's energy consumption is reduced to a minimum.

[0028] In a further advantageous embodiment of the invention, air, in particular unconditioned outside air or recirculated air, is directed past the evaporator and the heat exchanger by means of an openable and closable bypass vent. This allows, for example, simple control of the air temperature by mixing unconditioned outside air or recirculated air with the air conditioned by the evaporator and / or the heat exchanger through the openable and closable bypass vent, which is then supplied, for example, to the passenger compartment of a motor vehicle. Advantageously, a further airflow control device, for example a controllable air flap, is arranged in the bypass vent or at an inlet or outlet opening of the bypass vent for this purpose.

[0029] Further advantageous details and effects of the invention are explained in more detail below with reference to an embodiment illustrated in the drawing. The drawing shows: Fig. 1 a schematic representation of an air conditioning system according to an exemplary embodiment, Fig. 2 a flowchart to explain a charging process of the cold storage unit according to the exemplary embodiment and Fig. 3 a flowchart to explain a discharge process of the cold storage unit according to the exemplary embodiment.

[0030] In the different figures, identical parts are always provided with the same reference symbols, so that they are usually only described once.

[0031] In Fig. Figure 1 schematically depicts an air conditioning system 1 according to an exemplary embodiment. The air conditioning system 1 shown is, in particular, a heating and air conditioning (HVAC) system for a [unclear] located in the Fig. 1 motor vehicle (not shown) with a start-stop system. As the Fig. As can be seen from Figure 1, the air conditioning system 1 has a refrigerant circuit (not shown in detail) with an evaporator 2 and a heating circuit 4 with a heat exchanger 5, which is fluidly connected to a coolant circuit 3.

[0032] Coolant circuit 3 has an essentially conventional design, as in Fig. The structure shown in Figure 1 comprises a drive motor 6 of the motor vehicle, for example an internal combustion engine or an electric motor, which is fluidly connected to a radiator 7. The fluid contained in the coolant circuit 3, for example water or coolant, is circulated by means of a coolant pump 8. Furthermore, in Fig. 1 a thermostat 9 is shown, which connects or disconnects the cooler 7 from the coolant circuit 3 in a known manner depending on the coolant temperature of the coolant circuit 3 or the operating temperature of the drive motor 6.

[0033] As previously described, coolant circuit 3 is fluid-conductingly connected to heating circuit 4, meaning that the same fluid circulates in heating circuit 4 as in coolant circuit 3, for example, water or coolant. As the Fig. As can be further seen from Figure 1, a controllable valve 10, for example a flow control valve, is arranged between the coolant circuit 3 and the heating circuit 4, with which the heating circuit 4 can be separated from the coolant circuit 3 or fluid-conductingly connected to it. Furthermore, according to the illustrated embodiment, the valve 10 is also designed to fluid-conductly connect or disconnect a fluid storage tank 11 from the heating circuit 4. Advantageously, the controllable valve 10 is, for example, a multi-way control valve to which both the coolant circuit 3 and the fluid storage tank 11 are connected, so that a single control command can be used to control the flow between the two circuits. Fig. 1 control unit not shown for carrying out the inventive method which is explained in more detail below, the coolant circuit 3 is separated from the heating circuit 4 and at the same time the fluid storage tank 11 is connected to the heating circuit 4 in a fluid-conducting manner.

[0034] To ensure sufficient circulation of the fluid contained in the heating circuit 4 and the storage tank 11, a fluid pump 12 is arranged in the heating circuit 4 according to the exemplary embodiment. The flow directions of the fluid in the coolant circuit 3 and in the heating circuit 4 are indicated by corresponding arrows in Fig. 1 marked.

[0035] Furthermore, the in Fig. 1 Air conditioning system 1 a first airflow control device 13, for example a temperature control flap, with which the air 14 flowing through the evaporator 2, which for example by means of a Fig. The airflow control device 13 is advantageously designed to continuously control or adjust the proportion of air supplied to the heating heat exchanger 5, relative to the air flowing through the evaporator 2, within a range of approximately 0% to approximately 100%, as shown in the diagram. This air is supplied by a blower (not shown) either as fresh air or outside air from the environment outside the vehicle or as recirculated air from a passenger compartment (also not shown). Fig. 1 can be seen from two dashed lines and a corresponding arc of arrow depicted limiting the airflow control device 13.

[0036] The air 15 not supplied to the heating heat exchanger 5 by the airflow control device 13 is expediently routed past the heating heat exchanger 5 and blown as conditioned air 16, for example, into a passenger compartment. As can be seen from the Fig. As can also be seen in Figure 1, the air 17 flowing through the heat exchanger 5 is subsequently mixed with the air 15 surrounding the heat exchanger 5 and supplied, for example, to the passenger compartment as conditioned air 16. By dividing the air 14 into an air component 15 and an air component 17, the temperature of the conditioned air 16 can be easily controlled by the airflow control device 13 and adjusted to the current cooling or heating requirements, for example, for the passenger compartment.

[0037] Furthermore, the air conditioning system 1, according to the [document / section], features [information / component]. Fig. In the embodiment shown in Figure 1, a bypass 18 can be opened and closed, and a second airflow control device 19, for example a controllable air flap, is arranged on the bypass 18. The bypass 18 allows the air 14, which is supplied to the air conditioning system 1 from the environment outside the vehicle as fresh air or outside air, or from a passenger compartment as recirculated air, to be directed past both the evaporator 2 and the heat exchanger 5. Preferably, the bypass 18 can be fully opened and closed, or only partially opened or closed, by means of the airflow control device 19, so that the temperature of the air conditioning air 16 can be set and controlled over a wide range by supplying and mixing it with non-air-conditioned outside air or recirculated air.

[0038] Based on the in the Fig. 2 and Fig. The following is an embodiment of the inventive method for controlling the flowcharts shown in Figure 3. Fig. The air conditioning system shown in Figure 1 is described. It should be understood that the steps indicated in the respective flowcharts can be carried out in a known manner by a suitably designed control device, for example, a device comprising a microcontroller or the like. Fig. 1 such a control device and the corresponding control lines with which such a control device is connected to the respective controllable components, for example the valve medium 10, the fluid pump 12 and the air flow control devices 13 and 19, and the sensors of the air conditioning system 1, for example temperature sensors, are not shown for the sake of simplicity.

[0039] The in Fig. Flowchart 2 illustrates the step of charging the heating circuit 4, which is used as a cold storage unit, according to the embodiment described herein. If it is generally determined that cooling capacity is required from the air conditioning system 1, which is the case, for example, when the target temperature of a passenger compartment is lower than the ambient temperature or the actual temperature of the passenger compartment, a first step 21 checks whether the refrigerant circuit of the air conditioning system 1 is in operation. In the case that the vehicle's drive motor 6, for example, drives a compressor of the refrigerant circuit via a belt drive, the operating state of the refrigerant circuit can also be determined, for example, via the operating state of the drive motor 6 or the compressor.

[0040] If the result in step 21 is "No", meaning the refrigerant circuit is not in operation, the method according to the inventive embodiment continues at connection point 30, which is shown in the flow diagram in Fig. 3, which describes the step of unloading the cold storage unit, is specified.

[0041] If the result in step 21 is "Yes", meaning the refrigerant circuit is in operation, the method according to the exemplary embodiment continues with step 22, in which it is checked whether the temperature of the refrigerant circuit or the evaporator 2 is lower than the temperature of the heating circuit 4 or the heating heat exchanger 5. If the result in step 22 is determined to be "Yes", the method according to the exemplary embodiment continues with step 23, in which the heating circuit 4 is separated from the coolant circuit 3 by means of the valve means 10, in particular a multi-way control valve. Subsequently, in step 24, the fluid storage tank 11 is also connected to the heating circuit 4 by means of the valve means 10.In step 25 of the illustrated embodiment of the method according to the invention, the fluid pump 12 is put into operation in order to circulate the fluid contained in the heating circuit 4, the heating heat exchanger 5 and the fluid storage tank 11.

[0042] In the following step 26, at least a portion of the air 14 flowing through and cooled by the evaporator 2 is supplied to the heating heat exchanger 5 by means of the first airflow control device 13, in particular a temperature control damper. This air thus passes through the heating heat exchanger 5 and cools it as well as the fluid of the heating circuit 4 circulating through the heating heat exchanger 5 by means of the fluid pump 12. This charges the heating circuit 4, the heating heat exchanger 5, and the fluid contained in the heating circuit 4 with cold. After passing through the heating heat exchanger 5, the air 17 is preferably mixed with the air 15 not supplied to the heating heat exchanger 5.

[0043] Furthermore, in step 27 of the inventive method according to the exemplary embodiment, the temperature of the air conditioning air 16 is further controlled by mixing in non-air-conditioned air, which flows through the bypass passage 18 and whose quantity is determined by means of the second airflow control device 19, in particular a controllable air flap. Subsequently, the air conditioning air 16, which is suitably tempered in this way, is supplied, for example, to a passenger compartment of the motor vehicle.

[0044] If the result in step 22 mentioned above is "No", the method according to the exemplary embodiment continues with step 28, in which the fluid pump 12 is deactivated because the cold storage capacity of the heating circuit 4 is exhausted, since, as determined in step 22, the temperature of the refrigerant circuit or the evaporator 2 is no longer lower than the temperature of the heating circuit 4 or the heating heat exchanger 5. Subsequently, the method according to the exemplary embodiment continues with step 27 already described, in which the temperature of the air conditioning air 16 is controlled according to predetermined temperature setpoints, which is then supplied, for example, to a passenger compartment.

[0045] It should be mentioned here that the temperatures of the refrigerant circuit or the heating circuit 4 are determined according to the invention by means of suitable temperature measurement methods. In particular, for this purpose, the temperature of the fluid circulating in the refrigerant circuit or the heating circuit 4 can be measured directly, i.e. in the fluid, using appropriate sensors, or the temperature of the air after it has flowed through the evaporator 2 or the heating heat exchanger 5 can be measured.

[0046] After step 27 for temperature control of the air conditioning air 16 has been carried out, the method according to the inventive embodiment jumps back to step 21, so that steps 21 to 28 are carried out again as described.

[0047] As explained above, the inventive method according to the exemplary embodiment branches to connection point 30 when in the Fig. Step 21, as shown in section 2, is determined to be "No". The connection point 30 is in Fig. 3 is shown and represents the starting point of the flow diagram shown in this figure, which describes the step of discharging the heating circuit 4 used as a cold storage unit.

[0048] Again Fig. As can be seen in section 3, the unloading step is carried out when cooling capacity is generally required from the air conditioning system 1, which is the case, for example, when the target temperature of a passenger compartment is lower than the ambient temperature or the actual temperature of the passenger compartment. In a first step 31, it is checked whether the refrigerant circuit of the air conditioning system 1 is in operation. As already in step 21 of the Fig. As explained in section 2, in the case that the drive motor 6 of the motor vehicle, for example, drives a compressor of the refrigerant circuit via a belt drive, the operating state of the refrigerant circuit can also be determined, for example, via the operating state of the drive motor 6 or the compressor.

[0049] If the result in step 31 is "Yes", meaning that the refrigerant circuit is in operation, the method according to the invention continues at connection point 20, which is shown in the flow diagram of the Fig. 2 is indicated, that is, it is already mentioned in the explanation of the Fig. Step 2 of the described process for charging the cold storage unit was carried out.

[0050] If, however, the result in step 31 is "No", meaning the refrigerant circuit is not in operation, the method according to the exemplary embodiment continues with step 32, in which it is checked whether the temperature of the heating circuit 4 or the heating heat exchanger 5 is lower than the temperature of the refrigerant circuit or the evaporator 2. If it is determined in step 32 that the result is "Yes", the method according to the exemplary embodiment continues with steps 33, 34 and 35, each of which corresponds to the one described in Fig. The steps 23, 24 and 25 shown and already described correspond to the two steps. Therefore, for the sake of simplicity, this description is omitted.

[0051] For a short time after the refrigerant circuit is switched off as determined in step 31, the residual cold stored in the refrigerant circuit or the evaporator 2 is still sufficient to cool the air 14 flowing through the evaporator 2. However, the temperature of the refrigerant circuit or the evaporator 2 increases with the duration of the switched-off operating state and is no longer sufficient to cool the air 14. In step 36, at least a portion of the air 14 flowing through the evaporator 2 is then directed to the heating heat exchanger 5 by means of the first airflow control device 13, in particular a temperature control damper. As the air flows through the heating heat exchanger 5, it is cooled by the cold stored in the heating circuit 4, the heating heat exchanger 5, and the fluid circulating in the heating circuit 5; that is, the heating circuit 4, which is used as a cold storage unit, is discharged.

[0052] Furthermore, in step 36, according to the exemplary embodiment, the proportion of air 17 flowing through the heat exchanger 5 is increased with increasing temperature of the evaporator 2 or the refrigerant circuit, so that sufficient cooling of the air 17 flowing through the heat exchanger 5 is ensured for a sufficiently long period of time. After flowing through the heat exchanger 5, the air 17 is preferably mixed with the air 15 not supplied to the heat exchanger 5.

[0053] Step 37, which follows step 36, corresponds to step 27 from Fig. 2, which is why a further description of this step can be omitted here.

[0054] If the result in step 32, as already explained above, is "No", the method according to the exemplary embodiment continues with step 38, in which the fluid pump 12 is deactivated, i.e., switched off, because the heating circuit 4 can no longer cool the air flowing through the heat exchanger 5, since, as determined in step 32, the temperature of the heating circuit 4 or the heat exchanger 5 is no longer lower than the temperature of the refrigerant circuit or the evaporator 2. Subsequently, the method according to the exemplary embodiment continues with step 37, which has already been described, in which the temperature of the air conditioning air 16 is controlled according to predetermined temperature setpoints.

[0055] After step 37 has been executed, the method according to the invention, in the exemplary embodiment, jumps back to step 31, from where steps 31 to 38 are again carried out as described.

[0056] As explained above, the inventive method according to the exemplary embodiment branches to connection point 20 when in the Fig. Step 31, as shown in section 3, is determined to be "Yes". The connection point 20 represents the starting point of the [section / project]. Fig. The flowchart shown in section 2 illustrates the step of charging the heating circuit 4, which is used as a cold storage unit, as already explained above.

[0057] The inventive method for controlling an air conditioning system is of course not limited to the embodiment described herein and shown in the figures.

[0058] In a preferred embodiment, the inventive method is used to control an air conditioning system, in particular a heating and air conditioning system (HVAC), for a motor vehicle with a start-stop system, in which a drive motor of the motor vehicle also drives the refrigerant circuit of the air conditioning system, for example by means of a compressor coupled to the drive motor via a belt drive, and the heating circuit of the air conditioning system is fluidly connected to a cooling circuit of the drive motor. Reference symbol list: 1 air conditioner 2 evaporators 3 Coolant circuit 4 heating circuits 5 heating heat exchangers 6 Drive motor 7 coolers 8 Coolant pump 9 Thermostat 10 Controllable valve medium 11 fluid storage tanks 12 Fluid pump 13 First airflow control device 14 Outdoor / Recirculated Air 15 Heating heat exchanger bypass air 16 Air conditioning 17 Heating heat exchanger air 18 Bypass passage 19 Second Airflow Control Device The following are the procedure steps corresponding to reference numerals 20 to 28 of the in Fig. The following are listed in the flowcharts shown: 20 Cooling requirement exists; (e.g. passenger compartment target temperature < ambient temperature) 21. Is the engine / refrigerant circuit running? 22. Evaporator temperature < heating heat exchanger temperature? 23. Separate the heating circuit from the coolant circuit using a valve. Connect 24 fluid storage tanks to the heating circuit using a valve. 25. Start up the fluid pump 26. Supply a portion of the air cooled by the evaporator to the heating heat exchanger by means of a first airflow control device. 27 Control the temperature of the air conditioning air by mixing in non-air-conditioned air flowing through the bypass channel using a second airflow control device. 28 Cold storage completed; fluid pump switched off. The following are the process steps corresponding to reference numbers 30 to 38 of the in Fig. The following are listed in the 3 flowcharts shown: 30 Cooling requirement exists (e.g. passenger compartment target temperature < ambient temperature) 31. Is the engine / refrigerant circuit running? 32 Heating heat exchanger temperature < Evaporator temperature? 33 Separate the heating circuit from the coolant circuit using a valve. 34 Connect fluid storage tanks to the heating circuit using a valve. 35. Start up the fluid pump 36. Direct a portion of the air flowing through the evaporator to the heating heat exchanger by means of a first airflow control device; increase the proportion as the evaporator temperature increases. 37 Control the temperature of the air conditioning air by mixing in non-air-conditioned air flowing through the bypass channel using a second airflow control device. 38 Cold storage complete; shut down fluid pump

Claims

[1] Method for controlling an air conditioning system (1) comprising a refrigerant circuit with at least one evaporator (2) and a heating circuit (4) with at least one heat exchanger (5) connected fluid-conducting to a coolant circuit (3), comprising at least the following steps: - Charging the heating circuit (4) used as a cold storage unit with cold when it is determined that cooling capacity is required and the refrigerant circuit is in operation and the temperature of the refrigerant circuit and / or the evaporator (2) is lower than the temperature of the heating circuit (4) and / or the heating heat exchanger (5), then disconnecting the heating circuit (4) from the coolant circuit (3) and subsequently connecting a fluid storage tank (11) to the heating circuit (4) and circulating the fluid contained in the heating circuit (4), the heating heat exchanger (5) and the fluid storage tank (11) by means of a fluid pump (12) contained in the heating circuit (4), then supplying at least a portion of the air (14) flowing through and cooled by the evaporator (2) to the heating heat exchanger (5), and switching off the fluid pump (12) when it is determined thatthat the temperature of the refrigerant circuit and / or the evaporator (2) is no longer lower than the temperature of the heating circuit (4) and / or the heating heat exchanger (5), - Discharging the heating circuit (4) used as a cold storage unit, i.e., the cold stored in the heating circuit (4), and cooling the air (17) flowing through the heat exchanger (5) when it is determined that cooling capacity is required and the refrigerant circuit is not in operation and the temperature of the heating circuit (4) and / or the heat exchanger (5) is lower than the temperature of the refrigerant circuit and / or the evaporator (2), then disconnecting the heating circuit (4) from the coolant circuit (3) and subsequently connecting the fluid storage tank (11) to the heating circuit (4) by means of a fluid-conducting flow and circulating the fluid contained in the heating circuit (4), the heat exchanger (5) and the fluid storage tank (11) by means of the fluid pump (12), then supplying at least a portion of the air (14) flowing through and cooled by the evaporator (2) to the heat exchanger (5),wherein the proportion of air (17) flowing through the heating heat exchanger (5) is increased with increasing temperature of the evaporator (2) and / or the refrigerant circuit, and stopping the circulation of the fluid by switching off the fluid pump (12) when it is determined that the temperature of the heating circuit (4) and / or the heating heat exchanger (5) is no longer lower than the temperature of the refrigerant circuit and / or the evaporator (2). [2] Method according to claim 1, wherein the loading step and / or the unloading step comprises supplying at least a part of the air (17) flowing through the evaporator (2) to the heating heat exchanger (5) by means of an air flow control device (13). [3] Method according to claim 1 or 2, wherein the amount of air supplied to the heating heat exchanger (5) during the charging step and / or the discharging step is controlled by an air flow control device (13) depending on a temperature difference between the refrigerant circuit and / or the evaporator (2) and the heating circuit (4) and / or the heating heat exchanger (5). [4] Method according to any of the preceding claims, wherein the charging step and / or the discharging step comprises separating the heating circuit (4) from the coolant circuit (3) by means of a controllable valve means (10). [5] Method according to one of the preceding claims, wherein the loading step and / or the unloading step comprises the fluid-conducting connection of at least one fluid storage container (11) to the heating circuit (4) by means of a controllable valve means (10). [6] Method according to one of the preceding claims, wherein the separation of the heating circuit (4) from the coolant circuit (3) and the connection of at least one fluid storage container (11) to the heating circuit (4) are carried out by means of a single controllable valve means (10). [7] Method according to one of the preceding claims, wherein air (14) is passed past the evaporator (2) and the heating heat exchanger (5) by means of an openable and closable bypass passage (18). [8] Air conditioning system (1) comprising a refrigerant circuit with at least one evaporator (2) and a heating circuit (4) fluidly connected to a coolant circuit (3) with at least one heat exchanger (5), characterized by a control system for carrying out a process according to one of the preceding claims.

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