Control system for heat distribution and methods for operating a heat distribution system

Abstract

Method for operating a heat distribution system (2) of an electric or hybrid vehicle by means of a control system (4) which is designed in such a way that - that when a heating request is made for a battery (16), a battery heating operation is activated, in which the battery (16), which is connected to a battery circuit (12) of the heat distribution (2), is heated by means of a battery heating source (18), which is activated for this purpose, so that heat is generated in or transferred to the battery circuit (12), - wherein the battery heating source (18) is a battery auxiliary heater which is connected to the battery circuit (12), - that when a heating request is made for an interior (34) of the vehicle, a climate control heating mode is activated in which the interior (34) is heated by means of a heating circuit (14) with heat which is generated by an auxiliary heater (40) in the heating circuit (14) or is transferred to the heating circuit (14) by a heat pump or both, - that when the climate control heating operation is activated, it is determined whether there is a heating deficit, which indicates whether the heating demand can be fully met by the auxiliary heater (40) and the heat pump or not, - that, if a heating deficit exists, an auxiliary heating mode is activated in which heat from the battery heating source (18) is transferred from the battery circuit (12) to the heating circuit (14) by means of the heat pump in order to compensate for the heating deficit by using the battery heating source (18) in addition to the auxiliary heater (40) and supplementing its limited heating capacity, - that the output of a refrigeration circuit (8) of the heat distribution (2) is controlled by a compressor controller (R1), which uses as a manipulated variable a compressor speed (VD) of a compressor (62) in the refrigeration circuit (8) and to which as a controlled variable a heating circuit actual temperature (T-HK-I) of the coolant in the heating circuit (14) is supplied and as a reference variable a heating circuit setpoint temperature (T-HK-S), - that the compressor controller (R1) is used regardless of whether the auxiliary heating operation is activated in air conditioning / heating mode or not, - that the expansion valve (60) is controlled by a valve controller (R2), which uses as its actuating variable an opening (Ö) of the expansion valve (60) upstream of a cooler (20) of the heat pump in a refrigeration circuit (8) of the heat distribution (2) and to which as its controlled variable an actual superheat (Ü-I) in the refrigeration circuit (8) is supplied and as its reference variable a setpoint superheat (Ü-S), - that the valve controller (R2) is used regardless of whether the auxiliary heating operation is activated in climate control / heating mode or not, - that the cooling capacity of the radiator (20) is limited in auxiliary heating mode by taking the target superheat (Ü-S) from a characteristic map (K1) depending on a coolant actual temperature (T-KM-I) in the battery circuit (12) downstream of the radiator (20).

Description

[0001] The invention relates to a control system for a heat distribution system of an electric or hybrid vehicle and to a method for operating such a heat distribution system by means of such a control system.

[0002] A heat distribution system is typically used to regulate the temperature of various components connected to the heat distribution system. In an electric or hybrid vehicle, such components include the vehicle's interior and battery. The heat distribution system can be operated in various operating modes to meet the specific temperature requirements of the individual components.

[0003] DE 10 2015 220 623 A1 describes a heat distribution system with heat pump operation, in which waste heat can be transferred to a heating heat exchanger in a heating circuit using a heat pump, where it can be used to heat the interior. Various options are available for supplying the heating heat exchanger with heat: Firstly, if the battery is cooled in battery cooling mode, its heat is used for heating. Secondly, if a heat source in the cooling circuit is to be cooled, its heat is used analogously. And thirdly: a classic absorption of heat from the environment via an ambient cooler. The heat pump is used in each of the three cases. In addition, an auxiliary heater in the heating circuit is described, which compensates for a heat deficit in the heating circuit if the heat supply from the heat pump operation is insufficient.

[0004] Further heat distributions are described in DE 10 2018 002 708 A1, DE 10 2016 200 362 A1, DE 10 2013 110 224 A1, DE 10 2014 226 346 A1, DE 603 ​​19 291 T2, DE 10 2013 006 356 A1 and DE 38 09 136 A1.

[0005] However, it remains problematic that the heat entering the heating circuit may not be sufficient to adequately meet a given heating requirement for the interior, resulting in a heating deficit that leads to a corresponding loss of comfort or deficiencies in window defrosting. Accordingly, it is necessary to avoid such a heating deficit by improving the control of heat distribution.

[0006] Against this background, one object of the invention is to provide an improved control system for heat distribution. Furthermore, an improved method for operating a heat distribution system is to be provided. Overall, the aim is to ensure the most effective and demand-oriented interior heating possible, with a heating deficit being reduced as much as possible or even completely avoided by appropriate control of the heat distribution.

[0007] The object is achieved by a method having the features of claim 1 and by a control system having the features of claim 9. Advantageous embodiments, further developments, and variants are the subject of the dependent claims. The statements relating to the control system also apply mutatis mutandis to the method, and vice versa.

[0008] The controller (also referred to as the "control system") is used to control heat distribution (also referred to as the "heating system") of an electric or hybrid vehicle, which will be referred to simply as the vehicle below. The vehicle has a coolant-cooled battery. This battery is connected to a battery circuit and is heated in battery heating mode. For this purpose, the controller is designed such that, when heating is requested for the battery, battery heating mode is activated. In this mode, the battery is heated using a battery heating source, which is activated for this purpose, so that heat is generated in or transferred to the battery circuit.The battery heating source is either connected directly to the battery circuit or to a cooling circuit of the heat distribution, which is then connected to the battery circuit by suitable actuators such that an extended battery circuit is formed in which the battery heating source is arranged upstream of the battery in order to heat it. Furthermore, when heating is required for an interior of the vehicle, an air conditioning heating mode is activated accordingly, in which the interior is heated using heat via a heating circuit. This heat is generated with an auxiliary heater in the heating circuit or transferred to the heating circuit using a heat pump, or both. If the heat pump is used, it extracts heat from the environment via an ambient cooler in the cooling circuit or transfers waste heat from a vehicle component connected to the cooling circuit to the heating circuit.

[0009] However, in air conditioning / heating mode, the heat from the auxiliary heater and the heat pump may not be sufficient under certain circumstances. Therefore, when air conditioning / heating mode is activated, a determination is made as to whether there is a heating deficit, which indicates whether the heating requirement can be fully met with the auxiliary heater, the heat pump, or both. In other words, a check is carried out to determine whether the heat that can be generated by the auxiliary heater and the heat pump alone or in combination is sufficient to meet the heating requirement. If the auxiliary heater and the heat pump alone or in combination are sufficient, it is determined that there is no heating deficit. Conversely, if the auxiliary heater and the heat pump are insufficient, it is determined that there is a heating deficit. If there is indeed a heating deficit, auxiliary heating mode is activated, in which the battery heating source is activated first, provided it is not already active due to battery heating mode.Furthermore, during auxiliary heating mode, the heat pump transfers heat from the battery heating source from the battery circuit to the heating circuit to compensate for the heating deficit. In summary, a battery heating source is used for the battery in auxiliary heating mode to compensate for a heating deficit in the interior. This represents a beneficial secondary use for the battery heating source.

[0010] The invention is based on the observation that in certain cases there is not enough heat available to heat the interior, i.e. there is a heating deficit. As described, the heat pump and the auxiliary heater are basically available for heating the interior. The heating deficit arises from the fact that the heat sources used are not sufficient in certain cases. For example, at extremely low outside temperatures of, for example, below -10°C, the environment may not provide a sufficient heat source for the heat pump. Waste heat from vehicle components is also not necessarily available. Depending on the magnitude of the heating requirement, the auxiliary heater may not be sufficiently dimensioned, especially to generate the required amount of heat at low outside temperatures. This is the case, for example, if rapid heating is desired or if the interior to be heated is very large, e.g.This is especially true for mid-range and luxury vehicles. A particular advantage of using a battery-powered heating source is that the auxiliary heater in the heating circuit does not need to be designed for special cases with high heating requirements, but can be smaller and dimensioned sufficiently for standard applications. This already results in corresponding cost and space savings. For example, the auxiliary heater has a heating output in the range of 4 kW to 5 kW, but can also be dimensioned differently depending on the specific vehicle design and heat distribution.

[0011] A key advantage of the invention is that the heating deficit is compensated for by using the battery heat source in addition to the auxiliary heater, advantageously supplementing its limited heating output. Heat absorption from the environment is particularly eliminated during auxiliary heating operation, as the heat pump is now used to transfer heat from the battery circuit to the heating circuit.

[0012] The aforementioned DE 10 2015 220 623 A1 describes the case where waste heat from the battery, which is to be dissipated in battery cooling mode, is used to heat the interior. However, this requires that the battery actually generates heat that can and should be dissipated, i.e. that battery cooling mode is active. In the present auxiliary heating mode, this is not necessary and in particular not the case because the battery heat source is used. This unlocks additional heat potential. Overall, this results in particularly effective and needs-based interior heating. Waste heat from the battery, on the other hand, is used particularly in air conditioning / heating mode when the heat pump transfers waste heat from a vehicle component, in this case the battery, to the heating circuit.

[0013] In auxiliary heating mode, heat is generated in the same way and with the same components as in battery heating mode; the heat is simply used for a different purpose. Auxiliary heating mode is essentially the same as battery heating mode, with the difference that it's not the battery that's heated, but the interior. Auxiliary heating and battery heating mode can also be activated simultaneously and are activated simultaneously as needed, so that the heat in the battery circuit is used partly to heat the battery and partly to heat the interior.

[0014] There are basically different ways to determine whether a heating deficit exists. In a suitable embodiment, the control system is designed in such a way that it determines that a heating deficit exists when the difference between the actual heating circuit temperature and the heating circuit setpoint temperature exceeds a maximum difference. The heating deficit either corresponds to the described difference or is derived from it. If the actual heating circuit temperature is lower than the heating circuit setpoint temperature and the difference is therefore negative, heat must continue to be supplied to heat the interior. The difference between the actual heating circuit temperature and the heating circuit setpoint temperature is also referred to as the control deviation in the heating circuit and is used preferably.

[0015] In an equally suitable alternative, the control is designed in such a way that it is determined that there is a heating deficit if the difference between a target heating output and a heating output potential exceeds a maximum difference, whereby the target heating output is determined based on the heating requirement and the heating output potential is determined based on a maximum heating output of the auxiliary heater and the heat pump. Therefore, instead of only considering the current temperature situation in the heating circuit, in this embodiment it is calculated whether the maximum heating output that the auxiliary heater and the heat pump can provide corresponds to the target heating output that is required to meet the heating requirement. The heating output of the heat pump takes into account, in particular, the outside temperature, the coolant temperature in the cooling circuit and, if applicable, the waste heat from vehicle components. The target heating output is determined in particular based on current conditions such as, for example,Air volume, volume flow, air and / or coolant temperatures at the heating heat exchanger are determined.

[0016] Both variants for determining the heating deficit can in principle be combined with each other and are then used in parallel.

[0017] A difference between the actual heating circuit temperature and the target heating circuit temperature or between the target heating output and the potential heating output does not necessarily mean that the auxiliary heater and the heat pump are insufficient to meet the heating requirement. Therefore, in a preferred embodiment, the control is designed such that auxiliary heating operation is activated with a delay by waiting for a waiting period if a heating deficit exists before auxiliary heating operation is activated. This ensures that the maximum difference is not merely exceeded temporarily, but that it still exists after the waiting period and that additional heat is therefore actually required on a permanent basis. In particular, it is also advantageous to monitor the temporal development of the difference and only detect a heating deficit if the difference is not decreasing or is not decreasing at a certain minimum rate.This gives the auxiliary heater and heat pump the opportunity to initially reduce the difference during the waiting period. Only if this fails and the heating capacity of the auxiliary heater and heat pump is actually insufficient is auxiliary heating activated. Furthermore, the waiting period prevents auxiliary heating from being activated immediately if the heating demand is only initially high, for example, if a user accidentally sets a high target heating circuit temperature for the interior. Instead, the system waits to see whether the heating deficit actually persists. The statements regarding the waiting period also apply analogously to the reverse case of deactivating auxiliary heating.

[0018] The heat pump is controlled appropriately by the control system depending on the requirement and is preferably regulated to meet the heating requirement for the interior or the battery or both as optimally as possible, depending on the size of the heating requirement and the heat available, if necessary in combination with the auxiliary heater.

[0019] The heat pump is part of a refrigeration circuit for heat distribution and has a cooler (also known as a “chiller”) and a condenser, both of which are connected to the refrigeration circuit. On the coolant side, the cooler is connected to the battery circuit and the condenser is connected to the heating circuit. The refrigeration circuit has a compressor that operates at a specific compressor speed, which is adjustable and set by the control system in order to set a specific heating and cooling output of the refrigeration circuit. The heating output of the refrigeration circuit, or more precisely of the heat pump, i.e. the amount of heat transferred from the heat pump to the heating circuit, depends on the electrical drive power of the compressor and the cooling output of the refrigeration circuit, or more precisely of the cooler, i.e. the heat extraction from the battery circuit by the cooler.

[0020] The refrigeration circuit also includes an air conditioning evaporator for cooling the interior in air conditioning cooling mode. An expansion valve is located upstream of the air conditioning evaporator and the cooler. This valve is opened to activate the evaporator and closed to deactivate it. The air conditioning evaporator is deactivated in air conditioning heating mode. In the following, the term "expansion valve" refers to the expansion valve upstream of the cooler, unless otherwise stated. The expansion valve operates with a specific opening, which is adjustable and set by the control system to establish a specific refrigerant superheat and thus adjust the cooling capacity of the cooler.

[0021] The compressor speed, which is preferably set via the control deviation in the heating circuit, ultimately determines the refrigerant mass flow and thus also the cooling capacity at the cooler, which is then additionally influenced by the opening of the expansion valve. Closing the expansion valve reduces the refrigerant mass flow, thereby reducing the cooling capacity, which results in higher refrigerant superheat downstream of the cooler. Conversely, opening the expansion valve increases the refrigerant mass flow, thereby increasing the cooling capacity and thus reducing the refrigerant superheat. In other words: by opening the expansion valve, the cooling capacity at the cooler, which was set by the compressor speed, can be reduced again and thus additionally adjusted. The compressor must then be controlled at a higher speed so that the desired cooling capacity is achieved again.This means that it requires a higher drive power.

[0022] Since the heating output of the heat pump is the sum of the drive power of the compressor and the cooling capacity of the cooler, in a preferred embodiment the efficiency of the heat pump in auxiliary heating mode is manipulated by means of the expansion valve in such a way that the required heating output for auxiliary heating is achieved with the lowest possible and at the same time limited heat extraction from the battery circuit. This is particularly advantageous if the battery heating mode is active at the same time as the auxiliary heating mode, which requires a certain heat in the battery circuit and thus limits the possible heat extraction by the cooler. In a particularly preferred embodiment the heat pump is controlled in such a way that its efficiency is set such that the heat extraction from the battery circuit is limited while the heating deficit is still compensated.In other words: when auxiliary heating and battery heating are activated simultaneously, the compressor and the expansion valve are controlled in such a way that the heat, which is taken from the battery circuit via the heat pump and transferred to the heating circuit, in conjunction with the drive power of the compressor, compensates for the heating deficit and is nevertheless limited so that the battery is still sufficiently heated. The efficiency of the heat pump results in particular from the ratio of the drive power of the compressor to the heating power and is therefore fundamentally dependent on the cooling capacity of the cooler. The efficiency can be adjusted, in particular automatically, via the compressor speed and the opening of the expansion valve. By adjusting the efficiency, the composition of the cooling capacity and drive power for a specific heating output is set, i.e.The ratio of heat extraction from the battery circuit to the electrical power for the compressor is adjusted. This limits the heat extraction by the cooler, i.e., its cooling capacity, to the heat available in the battery circuit and supplements this with additional drive power from the compressor to achieve a specific heating capacity. The heat available in the battery circuit is determined by the total heat available in the battery circuit and the portion of this heat required to heat the battery. The available heat is determined primarily based on the actual coolant temperature downstream of the cooler and upstream of the battery. The heating capacity is determined by the heating deficit to be compensated.

[0023] When auxiliary heating is activated, the air conditioning / heating mode is always active as well. If auxiliary heating mode is active, the expansion valve and compressor are preferably controlled according to the same control logic as in air conditioning / heating mode without additional auxiliary heating mode, provided the heat pump is active.

[0024] In this case, the control system is designed such that the output of the heat distribution refrigeration circuit is regulated by a compressor controller. This controller uses the compressor speed as the manipulated variable, the actual temperature of the coolant in the heating circuit as the controlled variable, and the heating circuit setpoint temperature as the reference variable. The compressor controller is used regardless of whether auxiliary heating is activated in air conditioning / heating mode. The greater the difference between the actual heating circuit temperature and the heating circuit setpoint temperature, the higher the compressor speed is set and the more heat output the refrigeration circuit generates overall. In air conditioning / heating mode, the overall goal of the compressor controller is to meet the heating demand and bring the actual heating circuit temperature closer to the heating circuit setpoint temperature.

[0025] If battery heating is active at the same time as auxiliary heating, the heat pump and the battery compete for heat in the battery circuit. In particular, the cooler is located upstream of the battery and downstream of the battery heating source in the battery circuit and thus extracts heat from the battery circuit before it reaches the battery, which may mean that the battery is not heated sufficiently. Therefore, in a preferred embodiment, the control system is designed such that the compressor controller is limited in auxiliary heating mode such that the cooling capacity of the cooler in the battery circuit is limited. For this purpose, the compressor controller, or more precisely the compressor speed, is limited depending on the actual coolant temperature in the battery circuit downstream of the cooler. The output of the heat pump is therefore controlled such that the heat extraction by the heat pump is limited and thus sufficient heat remains to heat the battery.

[0026] When the air conditioning and heating mode is active, the heat pump's performance is influenced by regulating the expansion valve to the refrigerant's superheat. In this case, the control system is designed such that the expansion valve is controlled by a valve controller that uses the opening of the expansion valve upstream of the cooler as a manipulated variable and to which an actual superheat in the refrigerant circuit is supplied as a controlled variable and a target superheat as a reference variable. The valve controller is used regardless of whether or not auxiliary heating mode is activated in air conditioning and heating mode. When auxiliary heating mode is activated, the target superheat influences the amount of heat taken from the battery circuit for interior heating. The relationship is such that with a lower target superheat, the expansion valve opens less, and thus more heat is transferred from the heat pump to the heating circuit.With a larger heating deficit, a lower target superheat is selected.

[0027] Analogous to the compressor controller, the valve controller is also expediently limited in order to limit the heat extraction from the battery circuit and to artificially reduce the efficiency in auxiliary heating mode, so that as much drive power as possible is generated for the compressor, which is ultimately also used via the heat pump to heat the interior, especially when the battery heating mode is active at the same time. Two variants are described below, which can basically also be combined with each other. In the present case, the control is designed in such a way that the output of the heat pump, i.e. in this case the cooling output of the radiator, is limited in auxiliary heating mode by taking the target superheat from a characteristic map depending on the actual coolant temperature in the battery circuit downstream of the radiator. In a fundamentally conceivable alternative, the control is designed in such a way that the output of the heat pump, i.e.In this case, the cooling capacity of the radiator is limited in auxiliary heating mode by reducing the opening of the expansion valve as the actual coolant temperature in the battery circuit downstream of the radiator increases. As a result, it is ensured in every case that the battery continues to be sufficiently heated despite heat being drawn from the radiator.

[0028] The limitation of heat extraction when controlling the expansion valve or the compressor, or both, is alternatively specified by a battery control unit of the battery, which transmits a manipulated variable or the cooling capacity of the cooler as a controlled variable to a control unit that controls the compressor and the expansion valve. The battery control unit is a key component of the control system.

[0029] When battery heating is deactivated, the heat pump or the auxiliary heater, or both, are preferably activated for air conditioning heating operation, depending on the case. If, in the first case, the heating requirement for the interior can be met entirely by the heat pump from the environment or by waste heat from components in the cooling circuit, only the heat pump is activated, which then extracts heat from the environment or waste heat from other components in the cooling circuit to heat the interior. Here, too, the controllers for the compressor and expansion valve described above are expediently used, but in particular without the limitations described, so that maximum effectiveness is achieved. Whether the heat pump alone is sufficient is determined, for example, based on the outside temperature or a coolant temperature in the cooling circuit and the heating requirement.If, in a second case, the heating requirement for the interior cannot be fully met by the heat pump from the ambient air, the auxiliary heater is activated preferentially to generate heat for interior heating, and the heat pump is additionally activated only when the auxiliary heater's heating output is insufficient. In this case, too, the compressor and expansion valve are controlled, in particular, as already described. Overall, this results in a prioritization of the auxiliary heater, which is more effective than a reverse prioritization, in which a performance deficit of the heat pump would be compensated for by the auxiliary heater.

[0030] Preferably, the control system is configured such that the battery heating source is activated when the auxiliary heating mode or the battery heating mode, or both, are active. Additionally, the battery heating source is controlled by a heating controller, which uses a heating output of the battery heating source as a manipulated variable and to which an actual coolant temperature of the coolant upstream of the battery is supplied as a controlled variable and a corresponding coolant target temperature is supplied as a reference variable.

[0031] If auxiliary heating and battery heating are activated at the same time, there is a correspondingly high heat requirement in the battery circuit, which is optimally served by the control of the battery heat source described above. Heat extraction for interior heating depends on the heating deficit, which arises because the auxiliary heater in the heating circuit is not sufficient to meet the heating requirement. The heating controller then ensures that the necessary heat is extracted for interior heating and, on the other hand, that heat extraction from the battery circuit is limited so that the battery is sufficiently heated. Limiting heat extraction then ensures that battery heating is ultimately prioritized over interior heating, i.e. when the overall output of the auxiliary heater and the battery heat source is insufficient.

[0032] Interior heating using the heat pump with ambient heat and battery heating mode are mutually exclusive. This means that when battery heating mode and air conditioning heating mode are activated simultaneously, the heat for interior heating is generated by the auxiliary heater in the heating circuit, or auxiliary heating mode is activated, and thus, in addition to the auxiliary heater, heat is transferred from the battery heating source to the heating circuit via the heat pump. If battery heating mode is active but air conditioning heating mode is not, the cooler is shut off, particularly on the refrigerant side, by closing the expansion valve to prevent heat from being lost from the battery circuit via the heat pump.

[0033] After deactivating battery heating mode or auxiliary heating mode, or both, residual heat is usually still available in the battery circuit. This heat results from a temperature difference between the coolant in the battery circuit and the battery cell temperature. The coolant is warmer than the battery, and the difference is available as residual heat, beneficial for interior heating. Therefore, before the heat is absorbed from the environment or waste heat from other components in the cooling circuit in air conditioning / heating mode, this residual heat is first transferred to the heating circuit via the heat pump.In an expedient embodiment, the control unit is designed for this purpose in such a way that in air conditioning heating mode and when auxiliary heating mode for interior heating is inactive, the heat pump is activated and extracts residual heat from the coolant in the battery circuit, wherein the residual heat results as a heat surplus in the battery circuit from the fact that the actual coolant temperature upstream of the battery is greater than a cell temperature of the battery.

[0034] Where the heat in the battery circuit originates during auxiliary heating operation is initially of secondary importance. What is relevant, however, is that the heat enters the battery circuit, from where it reaches the cooler and is transferred by the heat pump. The heat is either generated directly in the battery circuit or transferred from the cooling circuit to the battery circuit via the coolant. In the latter case, the heat distribution is switched by the control system for auxiliary heating operation and, in particular, also for battery heating operation using suitable actuators in such a way that a section of the cooling circuit, on which the battery heat source is located, is connected to the battery circuit, thus expanding the latter and forming an expanded battery circuit in which the battery heat source is located upstream of the cooler.

[0035] In this case, the battery heat source is a battery auxiliary heater which is connected to the battery circuit, i.e. when active, generates heat directly in the battery circuit. The battery auxiliary heater is particularly similar to the auxiliary heater in the heating circuit and is preferably designed as an electric instantaneous water heater. In auxiliary heating mode, the battery auxiliary heater is then activated by the control system to generate heat to heat the interior. The controllers described above are preferably used here, so that the battery auxiliary heater automatically generates the required heating output for the battery or the interior or for both at the same time. The battery auxiliary heater, for example, has a heating output in the range of 4 kW to 5 kW. However, such a design is not mandatory and the battery auxiliary heater is dimensioned differently in one variant, depending in particular on the design of the battery.

[0036] Additionally, in an advantageous embodiment, a trimmed electric motor of the vehicle is used as a battery heating source. The electric motor serves to drive the vehicle and is supplied with electrical energy from the battery. The electric motor is connected to the cooling circuit of the heat distribution system. By trimming, the electric motor is deliberately operated inefficiently, thereby generating waste heat, which is then used for heating.

[0037] Overall, the behavior of the controller and thus also the heat distribution is largely determined by the temperature control requirements, which may result, for example, from a specific user input via a control element or which take into account ambient conditions determined by suitable sensors in the controller. Alternatively or additionally, a temperature control requirement is determined by a higher-level master controller, for example, an air conditioning logic.

[0038] The controller is connected to the heat distribution system, in particular, to control the heat distribution. This particularly means that the controller manipulates and adjusts the heat distribution using a number of actuators. Suitably, the controller comprises control electronics, in particular to carry out one or more of the aforementioned settings, controls, regulations, calculations, and / or other operations.

[0039] In the control and regulation concepts described above for the various components, the various characteristic maps are of particular importance. These maps are used, on the one hand, to determine additional parameters for the respective control or regulation and, on the other hand, to establish a relationship to the various control variables. The characteristic maps are determined primarily through suitable tests and, if appropriate, stored in a control system memory in the form of a value table or a calculation rule.

[0040] In the method for operating a heat distribution system in an electric or hybrid vehicle, the heat distribution is controlled by a controller as described above. This object is achieved, in particular, by an electric or hybrid vehicle with a controller as described above. This object is further achieved, in particular, by the use of a controller as described in an electric or hybrid vehicle. An electric or hybrid vehicle is characterized by the fact that it uses a battery for propulsion. The battery is also referred to as an energy storage device or "high-voltage storage device" (abbreviated to "HVS").

[0041] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In each case, the following schematically show: Fig. 1 a heat distribution and control system, Fig. 2 a refrigeration circuit for heat distribution, Fig. 3 a variant of the refrigeration circuit, Fig. 4 a control concept for a heat distribution compressor, Fig. 5 a control concept for an expansion valve of the heat distribution, Fig. 6 a control concept for a battery heating source for heat distribution.

[0042] In Fig. 1 shows a heat distribution system 2 and a controller 4 for controlling various components of the heat distribution system 2. The heat distribution system 2 is designed for use in an electric or hybrid vehicle (not shown in detail). The heat distribution system 2 has a total cooling circuit 6 and a refrigeration circuit 8, which is Fig. 1 is not shown, but for which two variants are shown in the Fig. 2 and Fig. 3. The heat distribution 2 in Fig. 1 represents a preferred embodiment, but the aspects described below, especially with regard to the interconnection of two components to each other, can also be applied individually.

[0043] The overall cooling circuit 6 comprises several circuits, namely a cooling circuit 10, a battery circuit 12 and a heating circuit 14. In addition, by appropriately switching the heat distribution 2, an extended battery circuit 12' can be formed, which is a combination of the battery circuit 12 with a section 15 of the cooling circuit 10. The circuits 10, 12, 12' and 14 are in Fig. 1 by dashed lines. A battery 16 is connected to the battery circuit 12 to supply an electric drive of the vehicle, and also a battery heat source 18, which here is a battery auxiliary heater and is designed as an electric instantaneous water heater. Furthermore, a cooler 20 is connected to the battery circuit 12, which is also connected to the cooling circuit 8. A vehicle component 24 of the vehicle, for example an electric motor of the vehicle or power electronics and generally a heat source, is connected to the cooling circuit 10 on the subsection 15. For heat exchange with the environment, a first ambient cooler 26 is also connected to the cooling circuit 8, which is combined here with a second ambient cooler 28 to form a cooler package. In principle, however, a design without the second ambient cooler 28 is also possible.

[0044] A heating heat exchanger 32 is connected to the heating circuit 14 for heating an interior 34 of the vehicle. A condenser 36 is also connected to the heating circuit 14, which is also connected to the cooling circuit 8 and, together with the radiator 20, forms a heat pump that transfers heat from the battery circuit 12 to the heating circuit 14. A supplementary heater 40, which here is designed as an electric instantaneous water heater, is also arranged in the heating circuit 14. The heating circuit 14 is connected to the cooling circuit 10 via a heating circuit flow 42 and a heating circuit return 44. The battery circuit 12 is also connected to the cooling circuit 8, but not to the heating circuit 14. Specifically in the wiring shown, by appropriately switching the heat distribution 2, either a series connection or a parallel connection of the battery 16 and the vehicle component 24 is possible, as well as the setting of the extended battery circuit 12'.

[0045] An air conditioning evaporator 56 is connected to the refrigeration circuit 8 for cooling the interior 34. An expansion valve 58 is connected upstream of the air conditioning evaporator 56 to adjust the cooling capacity. An expansion valve 60 is also connected upstream of the cooler 20. A compressor 62 is also arranged in the refrigeration circuit 8, as well as, in this case, one or two internal heat exchangers 64 within the cycle. In a variant not shown, no internal heat exchanger 64 is present.

[0046] The heat distribution 2 further has a compensation volume 52 for the coolant. Furthermore, temperature sensors 54 are connected at various points in the overall cooling circuit 6 to measure the temperature of the coolant. Various actuators, in this case valves, are arranged in the overall cooling circuit 6 to switch the heat distribution 2 between various switching states and to set different operating modes. Furthermore, three 3 / 2-way valves 68, 70, 72 are arranged, which, depending on the switching position, enable various series and parallel connections of the first ambient cooler 26, cooler 20, vehicle component 24, and battery 16. The heating circuit 14 can be shut off independently of these by means of the shut-off valve 66.

[0047] When a heating request is made for the battery 16, a battery heating mode is activated, in which the battery 16 is heated by means of the battery heating source 18, which is activated for this purpose so that heat is generated in the battery circuit 12. The battery heating source 18 is either as in Fig. 1, it is connected directly to the battery circuit 12 or, in a variant not shown, to the cooling circuit 10 and in the extended battery circuit 12'. When heating is requested for the interior 34, an air conditioning heating mode is activated accordingly, in which the interior 34 is heated by the heating circuit 14. This heat is generated by the auxiliary heater 40 or transferred to the heating circuit 14 by the heat pump. If the heat pump is used, it extracts heat from the environment via the ambient cooler 26 or transfers waste heat from the vehicle component 24 or the battery 16 to the heating circuit 14.

[0048] In air conditioning / heating mode, the heat from the auxiliary heater 40 and the heat pump may be insufficient under certain circumstances. Therefore, when air conditioning / heating mode is activated, a determination is made as to whether a heating deficit exists, which indicates whether the heating requirement can be fully met with the auxiliary heater 40 or with the heat pump, or both. If a heating deficit does indeed exist, auxiliary heating mode is activated, in which the battery heating source 18 is activated first, provided it is not already active due to battery heating mode. In auxiliary heating mode, heat from the battery heating source 18 is then transferred from the battery circuit 12 to the heating circuit 14 by means of the heat pump in order to compensate for the heating deficit.

[0049] Whether a heating deficit exists can generally be determined in different ways. For example, the controller 4 is designed in such a way that it determines that a heating deficit exists when a difference between an actual heating circuit temperature T-HK-I in heating circuit 14 and a target heating circuit temperature T-HK-S exceeds a maximum difference. Alternatively, it is determined that a heating deficit exists when a difference between a target heating output and a heating output potential exceeds a maximum difference, wherein the target heating output is determined based on the heating requirement and the heating output potential is determined based on a maximum heating output of the auxiliary heater 40 and the heat pump. In this case, the auxiliary heating mode is also activated with a delay by waiting for a further period if a heating deficit exists before the auxiliary heating mode is actually activated.

[0050] The amount of heat transferred from the heat pump to the heating circuit 14 is the sum of the drive power of the compressor 62 and the cooling capacity of the cooler 20. The compressor 62 is operated at a specific compressor speed VD, which is suitably adjusted to achieve a specific heating capacity of the cooling circuit 8. In this case, a specific cooling capacity is implemented at the cooler. In addition, a specific opening Ö is set for the expansion valve 60 to influence the cooling capacity of the cooler 20. Fig. 4 and Fig. 5 shows a control concept for the compressor 62 or the expansion valve 60.

[0051] The power of the refrigeration circuit 8 is controlled by a compressor controller R1 as in Fig. 4. The compressor controller R1 uses the compressor speed VD as the manipulated variable, while the actual heating circuit actual temperature T-HK-I in heating circuit 14 is supplied as the controlled variable and the heating circuit setpoint temperature T-HK-S as the reference variable, which is specified, for example, by an air conditioning function logic. The compressor controller R1 is used regardless of whether auxiliary heating mode is activated in air conditioning / heating mode or not. The greater the difference between the heating circuit actual temperature T-HK-I and the heating circuit setpoint temperature T-HK-S, the higher the compressor speed VD is set and the more heating output the refrigeration circuit 8 generates overall.

[0052] If the battery heating mode is active at the same time as the auxiliary heating mode, the heat pump and the battery 16 are in competition with regard to the heat in the battery circuit 12. Therefore, the compressor controller R1 is in Fig. 4 in auxiliary heating mode. For this purpose, the control unit 4 has a limiting controller BR, which limits the compressor speed VD, namely depending on the actual coolant temperature T-KM-I.

[0053] In Fig. Figure 5 illustrates how the heat pump's output is controlled during active air conditioning / heating operation. Expansion valve 60 is controlled by a valve controller R2, which uses the opening Ö of expansion valve 60 as the manipulated variable and is supplied with an actual superheat Ü-I in refrigeration circuit 8 as the controlled variable and a target superheat Ü-S as the reference variable. Valve controller R2 is also used regardless of whether auxiliary heating is activated or not during air conditioning / heating operation.

[0054] Analogous to compressor controller R1, valve controller R2 is also limited to limit heat extraction from battery circuit 12, especially when battery heating is active at the same time. Generally, the cooling capacity of cooler 20 is limited in auxiliary heating mode. This is achieved in a first variant by taking the target superheat Ü-S from a map K1, dependent on the actual coolant temperature T-KM-I in battery circuit 12 downstream of cooler 20. In another variant, the opening Ö of expansion valve 60 is reduced as the actual coolant temperature T-KM-I increases. Fig. 5 both variants are shown at the same time.

[0055] The battery heating source 18 is activated when the auxiliary heating mode or the battery heating mode or both are active. In addition, the battery heating source 18 is switched on as shown in Fig.6 is controlled by a heating controller R3, which uses a heating output of the battery heating source 18 as a manipulated variable and to which the actual coolant temperature T-KM-I is supplied as a controlled variable and a corresponding coolant target temperature T-KM-S is supplied as a reference variable.

[0056] When auxiliary heating and battery heating are activated simultaneously, a correspondingly high heat demand arises in the battery circuit, which is automatically and optimally served by the described control of the battery heating source 18 in conjunction with the two controls for the compressor 62 and the expansion valve 60. Heat extraction for interior heating depends on the heating deficit, which results from the auxiliary heater 40 in heating circuit 14 not being sufficient to meet the heating requirement. The heating controller R3 then ensures that the battery heating source 18 heats as needed to ensure, on the one hand, the required heat extraction for interior heating and, on the other hand, the heating of the battery 16. Limiting the heat extraction then ensures that, ultimately, heating of the battery 16 is prioritized over interior heating.

[0057] After deactivation of battery heating mode, residual heat is usually still available in battery circuit 12, resulting from a temperature difference between the coolant in battery circuit 12 and the cell temperature of battery 16. Before the auxiliary heating mode is additionally activated in air conditioning heating mode, the aforementioned residual heat is first transferred to heating circuit 14 by means of the heat pump. List of reference symbols 2 Heat distribution 4 Control 6 Total cooling circuit 8 Refrigeration circuit 10 Cooling circuit 12 Battery circuit 12' extended battery circuit 14 heating circuits 15 subsection 16 Battery 18 Battery heat source 20 coolers 24 vehicle components 26 first ambient cooler 28 second ambient cooler 32 heating heat exchangers 34 Interior 36 Capacitor 40 additional heaters 42 Heating circuit flow 44 Heating circuit return 52 compensation volume 54 Temperature sensor 56 air conditioning evaporators 58 Expansion valve (of the air conditioning evaporator) 60 Expansion valve (of the cooler) 62 compressors 64 cycle-internal heat exchangers 66 Shut-off valve 68 3 / 2-way valve 70 3 / 2-way valve 72 3 / 2-way valve BR limit controller Ö Opening K1 map R1 compressor controller R2 valve regulator R3 heating controller TG limit temperature T-HK-I Actual heating circuit temperature T-HK-S Target heating circuit temperature T-KM-I Actual coolant temperature T-KM-S coolant target temperature VD compressor speed Ü-I Actual superheat Ü-S Target superheat

Claims

[1] Method for operating a heat distribution (2) of an electric or hybrid vehicle by means of a controller (4) which is designed in such a way - that when a heating request is made for a battery (16), a battery heating operation is activated, in which the battery (16), which is connected to a battery circuit (12) of the heat distribution (2), is heated by means of a battery heating source (18) which is activated for this purpose, so that heat is generated in the battery circuit (12) or transferred thereto, - wherein the battery heating source (18) is a battery heater which is connected to the battery circuit (12), - that when a heating request is made for an interior (34) of the vehicle, an air conditioning heating mode is activated, in which the interior (34) is heated by means of a heating circuit (14) with heat which is generated by an auxiliary heater (40) in the heating circuit (14) or is transferred to the heating circuit (14) by a heat pump, or both, - that when the air conditioning / heating mode is activated, it is determined whether there is a heating deficit, which indicates whether the heating requirement can be fully met with the auxiliary heater (40) and the heat pump or not, - that, if there is a heating deficit, a supplementary heating operation is activated, in which heat from the battery heating source (18) is transferred from the battery circuit (12) to the heating circuit (14) by means of the heat pump in order to compensate for the heating deficit by using the battery heating source (18) in addition to the supplementary heater (40) and supplementing its limited heating output, - that the output of a refrigeration circuit (8) of the heat distribution (2) is controlled by a compressor controller (R1) which uses a compressor speed (VD) of a compressor (62) in the refrigeration circuit (8) as a manipulated variable and to which a heating circuit actual temperature (T-HK-I) of the coolant in the heating circuit (14) is supplied as a controlled variable and a heating circuit setpoint temperature (T-HK-S) as a reference variable, - that the compressor controller (R1) is used regardless of whether the auxiliary heating mode is activated or not in the air conditioning-heating mode, - that the expansion valve (60) is controlled by a valve controller (R2) which uses as a manipulated variable an opening (Ö) of the expansion valve (60) upstream of a cooler (20) of the heat pump in a refrigeration circuit (8) of the heat distribution (2) and to which an actual superheat (Ü-I) in the refrigeration circuit (8) is supplied as a controlled variable and a target superheat (Ü-S) as a reference variable, - that the valve controller (R2) is used regardless of whether the auxiliary heating mode is activated in the air conditioning-heating mode or not, - that the cooling capacity of the cooler (20) is limited in auxiliary heating mode by taking the target superheat (Ü-S) from a characteristic map (K1) as a function of an actual coolant temperature (T-KM-I) in the battery circuit (12) downstream of the cooler (20). [2] Method according to claim 1, wherein the controller (4) is designed such that it is determined that a heating deficit exists when a difference between a heating circuit actual temperature (T-HK-I) in the heating circuit (14) and a heating circuit target temperature (T-HK-S) exceeds a maximum difference. [3] Method according to claim 1, wherein the controller (4) is designed such that it is determined that a heating deficit exists when a difference between a target heating output and a heating output potential exceeds a maximum difference, wherein the target heating output is determined on the basis of the heating requirement and the heating output potential is determined on the basis of a maximum heating output of the auxiliary heater (40) and the heat pump. [4] Method according to one of claims 1 to 3, wherein the control (4) is designed such that the auxiliary heating operation is activated with a delay by waiting for a waiting time in the event of a heating deficit before the auxiliary heating operation is activated. [5] Method according to claim 4, wherein the control (4) is designed such that the compressor controller (R1) is limited in auxiliary heating operation by limiting the compressor speed (VD) of the compressor (62) as a function of an actual coolant temperature (T-KM-I) in the battery circuit (12) downstream of the cooler (20), so that the cooling capacity of the cooler (20) is limited. [6] Method according to one of claims 1 to 5, wherein the control (4) is designed such that when the auxiliary heating operation and the battery heating operation are activated at the same time, the heat pump is controlled such that its efficiency is adjusted such that the heat extraction from the battery circuit (12) is limited and the heating deficit is nevertheless compensated. [7] Method according to one of claims 1 to 6, wherein the controller (4) is designed such that the battery heating source (18) is activated when the auxiliary heating mode or the battery heating mode or both are active, and is controlled by a heating controller (R3) to which a heating power of the battery heating source (18) is supplied as a manipulated variable and to which an actual coolant temperature (T-KM-I) in the battery circuit (12) upstream of the battery (16) is supplied as a controlled variable and a coolant target temperature (T-KM-S) is supplied as a reference variable. [8] Method according to one of claims 1 to 7, wherein the control (4) is designed such that in air conditioning heating mode and in inactive auxiliary heating mode for interior heating, the heat pump is activated and extracts residual heat from the coolant in the battery circuit (12), wherein the residual heat results as a heat surplus in the battery circuit (12) from the fact that the coolant actual temperature (T-KM-I) upstream of the battery (16) is greater than a cell temperature of the battery (16). [9] Controller (4) which is designed to carry out a method according to one of claims 1 to 8. [10] Controller (4) according to claim 9, wherein the battery heating source (18) is an electric instantaneous water heater.

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