GB2575546A

GB2575546A - Heat flow management device and method for operating a heat flow management device

Info

Publication number: GB2575546A
Application number: GB1907693.4A
Authority: GB
Inventors: Durrani Navid; Hötzel Martin; Haas Tobias
Original assignee: Hanon Systems Corp
Current assignee: Hanon Systems Corp
Priority date: 2018-05-31
Filing date: 2019-05-30
Publication date: 2020-01-15
Anticipated expiration: 2039-05-30
Also published as: GB2575546B; GB201907693D0

Abstract

A heat flow management system 1 for an electric vehicle comprises a refrigerant circuit, a drive-train cooling circuit and a heating section circuit. The refrigerant circuit includes a compressor 2, indirect condenser 3, expansion valve 4, surroundings (i.e. ambient) heat exchanger 5, at least one evaporator - ideally a front 10 and rear 11 evaporator arranged in parallel - with associated expansion valves 7,8, and a chiller 12 with associated expansion valve 9. The drivetrain coolant circuit includes a first coolant pump 22, the chiller, an electric motor heat exchanger 29 and a radiator 32. The heating section circuit includes a second coolant pump 17, the indirect condenser and a heating heat exchanger 19 arranged to heat air for a passenger cabin of the electric vehicle. The drivetrain cooling circuit and the heating section circuit are thermally coupled to one another only indirectly by the refrigerant circuit. Ideally the drivetrain cooling circuit includes a battery cooler 25. Methods of operating the system in very cold, cold, low, mild and high ambient temperatures are also claimed.

Description

Heat flow management device and method for operating a heat flow management device

The invention relates to a heat flow management device as a constituent part of an air-conditioning system for high-efficiency vehicles with little waste heat generation.

In particular, the invention relates to a heat flow management system for electric vehicles (EV), vehicles with hybrid drive (HEV), plug-in hybrid (PHEV) or fuel-cell vehicles, which are driven at least in part by electric motor and which are equipped with high-voltage batteries or accumulators.

It is known in the prior art that electric vehicles, vehicles with both electric drive and combustion engine drive, so-called hybrids, fuel-cell vehicles and high-efficiency combustion-engine-powered vehicles do not generate enough waste heat to heat the vehicle cabin in winter in accordance with the demands for thermal comfort.

One inexpensive and structural-space-saving solution to this problem is an electric heater which is operated for example as a PTC heater in combination with a conventional refrigeration installation. The refrigeration installation cools the air flowing into the vehicle cabin, and the electric heater correspondingly warms said air.

Another, more efficient solution to this problem is an air-conditioning system with heat pump function, which however takes up a considerably greater amount of structural space than the abovementioned solution with an electric heater.

The heat pump systems of vehicles, in particular of passenger motor vehicles, have significant common features:

During cooling operation, the heat required for evaporating the refrigerant is absorbed from the feed air to the passenger cabin or from a coolant circuit. The coolant circuit is for example utilized for cooling electrical components. In the case of electrically driven vehicles, these are for example the traction battery, the inverter

- 2 or the converter.

In the condenser/gas cooler of the refrigerant circuit switched so as to act as refrigeration installation, the absorbed heat is released at a higher temperature level to the surroundings.

During heating operation, the heat required for evaporating the refrigerant is absorbed from a waste heat source. In the (interior compartment) condenser/gas cooler of the refrigerant circuit switched so as to act as heat pump, the heat is released at a high temperature level to the vehicle cabin, via the feed air, for heating purposes.

Normally, in heat pump systems, the ambient air is utilized as one of the main heat sources. The refrigerant is evaporated by virtue of heat being absorbed from the ambient air. This occurs either directly in a refrigerant-air heat exchanger or indirectly in a refrigerant-coolant heat exchanger.

The power and efficiency of a heat pump system is highly dependent on how much heat is available at what temperature level for evaporating the refrigerant. In the presence of cold ambient temperatures, the absorption of heat from the surroundings is additionally restricted in order to prevent icing of the surroundings heat exchanger. Normally, the maximum temperature difference between the temperature of the air entering the surroundings heat exchanger and the temperature of the refrigerant is limited. The maximum amount of heat absorbed from the ambient air is limited by means of this temperature difference.

As a result of icing of the surroundings heat exchanger, the heat transfer between air and refrigerant worsens, resulting in a reduction of the power absorbed from the surroundings and thus a worsening of the efficiency of the heat pump system as a whole.

Owing to the need to prevent icing of the surroundings heat exchanger, it is not possible in the presence of very cold ambient temperatures to sufficiently heat the

-3vehicle cabin if only the ambient air is utilized as a heat source. Therefore, an additional heat exchanger which operates as evaporator, the so-called chiller, is connected into the refrigerant circuit on the low-pressure side. The chiller permits a further absorption of heat from the water/glycol cooling circuit. The water/glycol cooling circuit cools for example the components of the electric drivetrain and under some circumstances also the battery cells of the high-voltage battery. This water/glycol cooling circuit also permits, by means of a low-temperature heat exchanger, the release of the waste heat directly to the surroundings without the need to imperatively operate the refrigerant circuit. Owing to the multiplicity of components that are normally required for such a system, the system complexity, and thus also the system costs per vehicle, are however increased.

According to the prior art, a relatively inexpensive solution to the problem with relatively little outlay in terms of apparatus thus consists in the combination of a refrigeration installation with a high-voltage PTC auxiliary heater. Such systems however disadvantageously exhibit high energy consumption with simultaneously relatively low discharge temperatures of the air for the heating of the vehicle cabin, in particular in cold regions. The electrical auxiliary heater is not energy-efficient and furthermore shortens the range in the case of vehicles operated using battery electricity. The electrical auxiliary heater is also only seldom used.

US 2017/0197488 A1 discloses a battery temperature monitoring device for vehicles and an air-conditioning system having the same. Here, a refrigerant circuit and multiple coolant circuits are provided in order to be able to heat the battery and the interior compartment of the vehicle simultaneously. For this purpose, an additional electric heater is also provided and integrated into the battery cooling circuit.

By contrast, heat pump systems are complex owing to the multiplicity of additional components such as heat exchangers, refrigerant valves and expansion elements.

Heat pump systems with exterior heat exchangers, also referred to as surroundings heat exchangers, are often designed such that, in relation to the pure cooling mode, a flow direction reversal is required for the switch to the heating mode. This switch

-4can be performed only when the refrigerant compressor has been deactivated.

Under some circumstances, this can lead to an undesired drop or increase in the discharge temperature of the air into the interior compartment of the vehicle cabin during the change in operating modes.

It is the object of the invention to provide a heat flow management device having a refrigerant circuit with heat pump functionality which, for the heating situation and for the cooling situation under steady-state conditions, can provide heat and cold for the passenger cabin of the vehicle in an efficient manner.

The object is achieved by means of a heat flow management device and by means of a method for operating said device having the features as per the independent patent claims. Refinements are specified in the dependent patent claims.

The object of the invention is achieved in particular by means of a heat flow management device for motor vehicles which, as main components, has a refrigerant circuit, a drivetrain coolant circuit and a heating section heat carrier circuit.

The refrigerant circuit has a compressor, an indirect condenser, an expansion element and an associated surroundings heat exchanger, wherein the surroundings heat exchanger can, after throttling of the refrigerant, be operated as an evaporator in the heat pump mode. Furthermore, at least one evaporator with associated expansion element for the air-conditioning of the air for the vehicle cabin, and a chiller with associated expansion element for the cooling of the drivetrain coolant circuit, are provided.

The drivetrain coolant circuit has a coolant pump, the chiller, an electric motor heat exchanger and a drivetrain coolant radiator. The heating section heat carrier circuit has a coolant pump, the indirect condenser and a heating heat exchanger, wherein the heating heat exchanger is arranged in an air-conditioning unit.

The refrigerant circuit and the drivetrain coolant circuit are directly thermally coupled

-5to one another by means of the chiller. Directly coupled means that the chiller is designed as a fluid-fluid heat exchanger, and the two fluid circuits can, in the chiller, transfer heat to the respective other fluid circuit.

The refrigerant circuit and the heating section heat carrier circuit are likewise directly thermally coupled to one another by means of the indirect condenser. The indirect condenser is in turn designed as a fluid-fluid heat exchanger, and the refrigerant circuit can, in the indirect condenser, transfer heat to the heating section heat carrier circuit. The drivetrain coolant circuit and the heating section heat carrier circuit are, by contrast to the direct thermal coupling, thermally coupled to one another only indirectly via the refrigerant circuit. No direct heat transfer is possible by means of a heat exchanger from the drivetrain coolant circuit to the heating section heat carrier circuit or vice versa.

The heating section heat carrier circuit and the drivetrain coolant circuit are preferably operated with a water-glycol mixture as heat carrier or coolant.

The concept of the heat flow management system thus consists in two coolant circuits being indirectly coupled via a refrigerant circuit. The refrigerant circuit comprises the customary components such as refrigerant compressor, indirect condenser for the warming of the heat carrier circuit with for example water-glycol mixture, four expansion elements, a 2/2-way switching valve and alternatively a coupled valve with the functionality of a switching and an expansion element, a surroundings heat exchanger which, in air-conditioning installation operation, operates as a condenser, and, in heat pump operation of the refrigerant circuit, operates as an evaporator. Also provided are a check valve, a chiller for battery cooling and/or waste-heat utilization, two evaporators in the air-conditioning units at the front and at the rear for the cooling or drying of the interior compartment air, a further check valve, a low-pressure-side refrigerant accumulator and dryer, and alternatively an internal heat exchanger optionally for increasing cooling efficiency.

The proposed heat flow management system comprises a refrigeration circuit, which is connected to two mutually independently operable coolant circuits. The first

-6coolant circuit, also referred to as heating section heat carrier circuit, is connected to a water-cooled condenser on the high-pressure side of the refrigeration circuit.

The coolant of this circuit thus functions as a heat carrier, as is reflected in the name heat carrier circuit.

The second coolant circuit, also referred to as a drivetrain coolant circuit, is connected to a chiller on the low-pressure side of the refrigeration circuit.

On the refrigeration circuit side, condensation heat can be released both in the water-cooled condenser and in the surroundings heat exchanger as refrigeration installation condenser in the front end, the cooler region of the vehicle. In cooling operation, the water-cooled indirect condenser can be circumvented by means of a bypass in order to avoid any pressure loss owing to this component. An expansion element is provided between the water-cooled indirect condenser and the aircontrolled surroundings heat exchanger in the front end in order to be able to perform closed-loop control of the operating pressure thereof between high pressure and low pressure. By means of this closed-loop average-pressure control, it is possible for heat to either be released in controlled fashion to the surroundings in refrigeration installation operation or to be absorbed from there in controlled fashion in heat pump operation. On the low-pressure side, there are three evaporators, two air-driven evaporators and a chiller in a parallel arrangement. Furthermore, a bypass past the AC condenser, the surroundings heat exchanger, is provided.

In the first heat carrier circuit, for example a water-glycol mixture, heat is absorbed and is transported to the heating register in the air-conditioning unit, the HVAC, in order to ultimately warm the interior compartment feed air.

The second coolant circuit, for example a water-glycol mixture, comprises multiple relatively small circuits, which can in each case be connected to one another and separated from one another for example by means of 3/2-way valves. The main function of these circuits is to cool electrical drivetrain components and/or batteries actively by means of refrigeration circuit cooling or passively by means of a heat exchanger installed in the front end as a radiator. In heating operation, this circuit is

- 7 configured for absorbing heat from the electrical drivetrain components. This formerly lost power is then transported to the chiller in order to provide evaporation heat. The absorption and incorporation of the lost power for the purposes of heating the vehicle increases the power and efficiency in heating operation.

All expansion elements can also be selectively completely closed, such that they can also be used as shut-off valves. The change between heating and cooling mode can be performed here in continuously variable fashion without refrigerant compressor deactivation. A flow reversal in the surroundings heat exchanger is not necessary in this system. This also leads to simplified oil management, because oil traps in the system can be more easily avoided.

Many systems from the prior art are either considerably more complex and expensive or are optimized only for one operating point.

It is preferable if, in the refrigerant circuit of the heat flow management device, a bypass with a shut-off valve is arranged in parallel with respect to the indirect condenser, such that, in refrigeration installation operation of the refrigerant circuit, during the cooling of the vehicle cabin or of the components, the indirect condenser can be circumvented via the bypass. In this way, the pressure loss in the refrigerant circuit is reduced, and efficiency is increased.

It is advantageous if, in the refrigerant circuit, two evaporators are arranged so as to be connected in parallel, wherein a front evaporator cools the air for the vehicle cabin in a front-end air-conditioning unit and a rear evaporator cools the air in a rearend air-conditioning unit.

Here, the evaporators are preferably each assigned an expansion element, such that the evaporators can be controlled in closed-loop fashion differently with regard to the evaporation temperature level.

It is furthermore advantageous if, in the refrigerant circuit, a low-pressure collector for the refrigerant is arranged upstream of the compressor.

-8It is furthermore preferable if, in the refrigerant circuit, an expansion element is arranged upstream of the surroundings heat exchanger, such that the surroundings heat exchanger can be utilized as an evaporator for heat absorption in the heat pump mode of the refrigerant circuit.

A bypass with shut-off valve in the refrigerant circuit in parallel with respect to the surroundings heat exchanger and its associated expansion element advantageously makes it possible for these to be circumvented.

In the drivetrain coolant circuit, there is advantageously arranged an additional coolant pump, such that, within the drivetrain coolant circuit, two mutually independently operable sub-circuits can be switched and implemented.

It is advantageous if, in the drivetrain coolant circuit, a bypass is formed in parallel with respect to the drivetrain coolant radiator, in order, in particular operating states, to release no heat via the drivetrain coolant radiator to the ambient air and instead keep the waste heat in the system of the heat flow management device and utilize said heat for heating tasks.

In the drivetrain coolant circuit, there is advantageously provided a bypass which forms a closed sub-circuit with the electric motor heat exchanger, the drivetrain coolant radiator and the additional coolant pump.

It is preferable if, in the drivetrain coolant circuit, there is arranged a battery cooler.

It is advantageous if, in the drivetrain coolant circuit, in parallel with respect to the battery cooler, there is arranged a bypass via which the battery cooler can be circumvented in the circuit.

In the drivetrain coolant circuit, in parallel with respect to the bypass, there is advantageously arranged a bypass by means of which a sub-circuit with the chiller, the battery cooler and the coolant pump can be formed. The provision of two

-9bypasses in parallel makes it possible for the drivetrain coolant circuit to be switched into and operated in two separately and mutually independently operable subcircuits.

It is preferable if, in the front-end air-conditioning unit, in addition to the heating heat exchanger, there is arranged an additional heating device by means of which the heating of the air for the vehicle cabin can additionally be performed.

The additional heating device is in this case preferably formed as a PTC (positive temperature coefficient) heating element.

For the open-loop and closed-loop control, the heat flow management device is preferably equipped with an open-loop and closed-loop control device, wherein, in the refrigerant circuit, in each case one pressure-temperature sensor is arranged downstream of the compressor, downstream of the surroundings heat exchanger and downstream of the chiller, and, in the refrigerant circuit, a temperature sensor is arranged downstream of the evaporator, and, in the drivetrain coolant circuit, in each case one temperature sensor is arranged upstream of the coolant pumps and downstream of the chiller and a temperature sensor is arranged in the air stream downstream of the evaporator, downstream of the heating device, downstream of the evaporator and upstream of the surroundings heat exchanger.

An advantageous addition to the heat flow management device consists in that, in the heating section heat carrier circuit, a heat carrier cooling radiator is, by means of a 3-way valve, arranged in parallel with respect to the heating heat exchanger.

A further advantageous variant of the heat flow management device consists in that, in the refrigerant circuit, downstream of the compressor, a heating condenser is arranged in a line loop, which can be shut off by means of a 3-way valve, so as to be switchable into a series configuration with respect to the surroundings heat exchanger.

The object of the invention is furthermore achieved by means of methods for

- 10 operating a heat flow management device.

Here, the methods for operating the heat flow management device relate to temperature ranges of the ambient temperatures. The temperature ranges begin with A with the temperature range of very cold ambient temperatures from approximately -20 °C to -8 °C, via the adjoining temperature range B of cold ambient temperatures up to approximately 5 °C, via the temperature range C with low ambient temperatures up to approximately 17 °C, to the temperature range D with mild ambient temperatures up to approximately 30 °C, and finally to the temperature range E which comprises high ambient temperatures above 30 °C.

It is advantageous if, in the temperature range E in the presence of high ambient temperatures, for the purposes of cabin and active battery cooling, the heat flow management device is switched such that the drivetrain coolant circuit is operated in two sub-circuits, wherein the first sub-circuit is switched so as to be composed of the chiller, the bypass, the battery cooler and the coolant pump, and the second sub-circuit is switched so as to be composed of the drivetrain coolant radiator, the coolant pump, the bypass and the electric motor heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the bypass with open shut-off valve, the surroundings heat exchanger, and the chiller, front evaporator and rear evaporator connected in parallel.

It is advantageous if, in the temperature range E in the presence of high ambient temperatures, for the purposes of cabin cooling, the heat flow management device is switched such that the drivetrain coolant circuit is formed so as to comprise the first sub-circuit composed of the chiller, the bypass, the battery cooler and the coolant pump, and the refrigerant circuit is switched so as to comprise the compressor, the bypass with open shut-off valve, the surroundings heat exchanger, and the front evaporator and rear evaporator connected in parallel.

It is advantageous if, in the temperature range E in the presence of high ambient temperatures, for the purposes of active battery cooling, the heat flow management device is switched such that the drivetrain coolant circuit is operated in two sub

- 11 circuits, wherein the first sub-circuit is switched so as to be composed of the chiller, the bypass, the battery cooler and the coolant pump, and the second sub-circuit is switched so as to be composed of the drivetrain coolant radiator, the coolant pump, the bypass and the electric motor heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the bypass with open shut-off valve, the surroundings heat exchanger and the chiller.

It is advantageous if, in the temperature range D in the presence of mild ambient temperatures, for the purposes of so-called reheating and for the purposes of passive battery cooling, the heat flow management device is switched such that the drivetrain coolant circuit is switched so as to be composed of the chiller, the electric motor heat exchanger, the drivetrain coolant radiator, the coolant pump, the battery cooler and the coolant pump, and the heating section heat carrier circuit is switched so as to comprise the coolant pump, the indirect condenser and the heating heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the indirect condenser, the surroundings heat exchanger and the front evaporator.

It is advantageous if, in the temperature range C in the presence of low ambient temperatures, for the purposes of efficient reheating, the heat flow management device is switched such that the drivetrain coolant circuit is switched so as to be composed of the chiller, the electric motor heat exchanger, the bypass, the coolant pump, the battery cooler and the coolant pump, and the heating section heat carrier circuit is switched so as to comprise the coolant pump, the indirect condenser and the heating heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the indirect condenser, the expansion element, the surroundings heat exchanger as evaporator for heat absorption, and the front evaporator.

It is advantageous if, in the temperature range C in the presence of low ambient temperatures, for the purposes of efficient reheating and for the purposes of simultaneous active battery and drivetrain cooling, the drivetrain coolant circuit is switched so as to be composed of the chiller, the electric motor heat exchanger, the bypass, the coolant pump, the battery cooler and the coolant pump. The heating section heat carrier circuit is switched so as to comprise the coolant pump, the

- 12 indirect condenser and the heating heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the indirect condenser, the expansion element, the surroundings heat exchanger as evaporator for heat absorption, and the chiller and front evaporator connected in parallel.

It is advantageous if, in the temperature range A and B in the presence of very cold and cold ambient temperatures, for the purposes of cabin heating, the drivetrain coolant circuit is switched so as to comprise the electric motor heat exchanger, the bypass, the coolant pump and the bypass. The heating section heat carrier circuit is switched so as to comprise the coolant pump, the indirect condenser and the heating heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the indirect condenser, the expansion element, the surroundings heat exchanger as evaporator for heat absorption, and the chiller.

In turn, it is advantageous if, in the temperature range A and B in the presence of very cold and cold ambient temperatures, for the purposes of cabin heating with waste heat, the drivetrain coolant circuit is switched so as to comprise the chiller, the electric motor heat exchanger, the bypass, the coolant pump, the bypass and the coolant pump. The heating section heat carrier circuit is switched so as to comprise the coolant pump, the indirect condenser and the heating heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the indirect condenser, the expansion element, the bypass with shut-off valve, the expansion element and the chiller.

A further advantageous refinement of the mode of operation of the heat flow management device consists in that, in the temperature range A and B in the presence of very cold and cold ambient temperatures, for the purposes of cabin heating with waste heat and ambient heat, the drivetrain coolant circuit is switched so as to comprise the chiller, the electric motor heat exchanger, the bypass, the coolant pump, a further bypass and the coolant pump. The heating section heat carrier circuit is switched so as to comprise the coolant pump, the indirect condenser and the heating heat exchanger, and the refrigerant circuit is switched so as to comprise the compressor, the indirect condenser, the expansion element, the

- 13surroundings heat exchanger as evaporator for heat absorption, the expansion element and the associated chiller.

In the temperature range A and B in the presence of very cold and cold ambient temperatures, for the purposes of battery preconditioning with waste heat, the drivetrain coolant circuit is switched so as to comprise the chiller, the electric motor heat exchanger, the bypass, the coolant pump, the battery cooler and the coolant pump.

Further details, features and advantages of refinements of the invention will emerge from the following description of exemplary embodiments with reference to the associated drawings, in which:

Figure 1 shows a circuit diagram of a heat flow management device,

Figure 2 shows a circuit diagram of a heat flow management device with sensors,

Figure 3 shows a switching configuration in the case of vehicle cabin and active battery cooling,

Figure 4 shows a switching configuration in the case of vehicle cabin cooling,

Figure 5 shows a switching configuration in the case of active battery cooling,

Figure 6 shows a switching configuration in the case of reheating and passive battery cooling,

Figure 7 shows a switching configuration in the case of efficient reheating and a single heat source,

Figure 8 shows a switching configuration in the case of efficient reheating and a double heat source,

Figure 9 shows a switching configuration in the case of vehicle cabin heating and an ambient heat source,

Figure 10 shows a switching configuration in the case of vehicle cabin heating and a waste heat source,

Figure 11 shows a switching configuration in the case of vehicle cabin heating and an ambient heat source and a waste heat source,

Figure 12 shows a switching configuration in the case of battery conditioning with

- 14a waste heat source,

Figure 13 shows a circuit diagram with expanded radiator capacity,

Figure 14 shows a circuit diagram with an internal condenser, and

Figure 15 shows a diagram of temperature ranges and operating mode.

Figure 1 shows the complete flow schematic of the heat flow management device 1 with all circuits, sub-circuits and device components. The heat flow management device 1 is composed substantially of three circuits which are thermally coupled to one another but operable independently of one another, wherein a circuit is in turn divisible into two sub-circuits, which are also operable autonomously and independently of one another.

The heat flow management device 1 has a refrigerant circuit which has, firstly, the customary main components. These are in particular the compressor 2 and the surroundings heat exchanger 5 as condenser/gas cooler and, as evaporators, the heat exchangers front evaporator 10 and rear evaporator 11 with the respectively associated expansion elements 7 and 8. Provided as an additional evaporator in the refrigerant circuit is the chiller 12 with the associated expansion element 9 for the cooling of the second circuit, the drivetrain coolant circuit. In the refrigerant circuit, the refrigerant vapour outlets of the evaporators 10,11,12 connected in parallel are merged, wherein a check valve 16 is arranged between the connection of the refrigerant vapour lines from the chiller 12 to the refrigerant vapour lines of the evaporators 10 and 11. In this way, in the refrigerant circuit, the chiller 12 can be operated as the sole evaporator, without refrigerant being able to pass into the nonoperated evaporators 10 and 11.

Finally, a low-pressure collector 13 is connected into the low-pressure side of the installation of the installation upstream of the compressor 2, before the circuit is completed. As a special feature, the refrigerant circuit has an indirect condenser 3 between the compressor 2 and the surroundings heat exchanger 5, which indirect condenser is however designed such that it can be circumvented by means of a bypass 34 with associated shut-off valve 14. The indirect condenser 3 heats the second circuit of the heat flow management device 1, the heating section heat

- 15carrier circuit, and thus supplies heat to the heating heat exchanger 19 for the purposes of heating the air for the vehicle cabin by means of a front-end airconditioning unit 35. For this purpose, a coolant pump 17 for conveying the heat carrier is furthermore provided in the heating section heat carrier circuit. As heat carrier, use is made of a water-glycol mixture, which may also simultaneously be used as coolant for the drivetrain coolant circuit.

Also provided as a special feature in the refrigerant circuit is a bypass 6 with a shutoff valve, which bypass is arranged in parallel with respect to the surroundings heat exchanger 5. In the refrigerant circuit, there is furthermore an expansion element 4 which is assigned to the surroundings heat exchanger 5 and thus positioned upstream of the latter in a refrigerant flow direction and by means of which the surroundings heat exchanger 5 can, after corresponding throttling of the refrigerant in the heat pump switching configuration of the refrigerant circuit, be utilized as an evaporator for absorbing ambient heat from the ambient air 33. The bypass 6, which can be shut off, has a shut-off valve and makes it possible for the refrigerant circuit to be operated with circumvention of the surroundings heat exchanger 5. In order to prevent an undesired backflow of refrigerant into the surroundings heat exchanger 5 during the operation of the refrigerant circuit via the bypass 6, a check valve 15 is correspondingly provided. The evaporators 10 and 11 each supply cold to the frontend air-conditioning unit 35 and the rear-end air-conditioning unit 36 in refrigeration installation operation and in reheat operation. The front-end air-conditioning unit 35 conditions the air for the vehicle cabin in the front-end region. For this purpose, the front-end air-conditioning unit is equipped not only with the evaporator 10 but also with the heating heat exchanger 19 and with an additional heating device 20 positioned downstream in an air flow direction. The heating device 20 is designed as a high-voltage PTC heater and thus permits energy-efficient additional electric heating of the air for the vehicle cabin.

The third circuit of the heat flow management device 1 is the drivetrain coolant circuit which supplies coolant to the drivetrain with the electric motor heat exchanger 29. Furthermore, also incorporated into the drivetrain coolant circuit is the battery cooler 25, which cools or conditions the batteries or accumulators of battery-powered

- 16vehicles.

Various bypasses 21, 23, 30 and 31 are integrated, by means of 3-way valves 27, 24, 26 and 18, into the drivetrain coolant circuit. Also provided is a drivetrain coolant radiator 32 which, together with the surroundings heat exchanger 5, is flowed through by ambient air 33 and cooled by the ambient air 33. The drivetrain coolant circuit is switchable into two sub-circuits, wherein each sub-circuit has a coolant pump 28 or 22. The switching configuration variants of the drivetrain coolant circuit will be discussed in the presentation of the individual operating modes.

In Figure 2, the above-described circuit diagram of the heat flow management device 1 has been supplemented to include the illustration of sensors for the openloop and closed-loop control of the heat flow management device 1. Here, three combined refrigerant pressure and temperature sensors 39 are arranged in the refrigerant circuit. One refrigerant pressure and temperature sensor 39 is seated between the compressor 2 and the indirect condenser 3, a further refrigerant pressure and temperature sensor 39 is arranged downstream of the surroundings heat exchanger 5 in the refrigerant circuit, and a third refrigerant pressure and temperature sensor 39 is arranged downstream of the chiller 12 in the refrigerant circuit. Furthermore, in the refrigerant circuit, a refrigerant temperature sensor 38 is arranged downstream of the front evaporator 10. Three temperature sensors are provided in the drivetrain coolant circuit. One coolant temperature sensor 40 is arranged upstream of the coolant pump 28. A further coolant temperature sensor 40 is arranged upstream of the coolant pump 22, and the third coolant temperature sensor 40 is arranged downstream of the chiller 12 in the drivetrain coolant circuit.

Furthermore, four air temperature sensors 37 are positioned in the heat flow management device 1. The first air temperature sensor 37 is situated downstream, in an air flow direction, of the front evaporator 10 in the front-end air-conditioning unit 35, the second air temperature sensor 37 is situated at the air outlet of the frontend air-conditioning unit 35, the third air temperature sensor 37 is situated downstream of the rear evaporator 11 of the rear-end air-conditioning unit 36, and finally, a fourth air temperature sensor 37 is arranged upstream of the inlet of the

- 17ambient air 33 into the surroundings heat exchanger 5.

In the following Figures 3 to 12, various operating modes of the heat flow management device 1 are illustrated in circuit diagram form. For improved clarity and comprehensibility, the switching states of the expansion elements have been made graphically distinguishable here. An expansion element shown as a filled black circle in the illustration is a completely closed expansion element which does not allow any refrigerant to pass through. An expansion element shown in the illustration as a circle with a cross is situated in a throttling position, and an expansion element shown in the illustration as an empty circle is fully open and has no throttling function.

The active, flowed-through lines for refrigerant and coolant or heat carrier liquid are likewise illustrated in the operating modes. Active flowed-through refrigerant lines are illustrated as thick continuous lines. Active flowed-through heat carrier lines of the heating section heat carrier circuit are illustrated as double lines with a close spacing, and active flowed-through coolant lines of the drivetrain coolant circuit are illustrated as double lines with a wide spacing. Inactive lines which are not flowed through in the respective operating mode are illustrated as thin continuous lines.

Figure 3 shows the switching configuration of the heat flow management device 1 in the case of vehicle cabin and active battery cooling. This mode is active if the ambient temperatures lie above 30 °C, as per temperature range E. An overview of the temperature ranges and operating modes is illustrated in Figure 15. In the operating mode of vehicle cabin and active battery cooling, the heating section heat carrier circuit of the heat flow management device 1 is not operated, such that the refrigerant circuit is switched so as to comprise the bypass 34 with open shut-off valve 14, with circumvention of the indirect condenser 3 downstream of the compressor 2. The refrigerant gas flows from the compressor 2 via the bypass 34 through the fully open expansion element 4 to the surroundings heat exchanger 5 and condenses there as a result of cooling with ambient air 33. The liquid, hot refrigerant then passes via the check valve 15 to the three heat exchangers 10,11, 12 connected in parallel which operate as evaporators, wherein the front evaporator with associated expansion element 7 cools the vehicle cabin in the front-end region in the front-end air-conditioning unit 35, and the rear evaporator 11 with associated expansion element 8 cools the air in the rear-end air-conditioning unit 36. The chiller 12 with associated expansion element 9 cools the coolant in the first sub-circuit of the drivetrain coolant circuit with the battery cooler 25. In the operating mode illustrated, the drivetrain coolant circuit is divided into two sub-circuits. The first sub-circuit, the battery cooling circuit, is switched so as to comprise the chiller 12, the 3-way valve 26 to the bypass 30, via the 3-way valve 24 to the battery cooler 25, and via the coolant pump 22 back to the chiller 12. The second sub-circuit of the drivetrain coolant circuit, the motor cooling circuit, runs from the coolant pump 28 via the 3-way valve 27 through the bypass 23 to the electric motor heat exchanger 29, via the 3-way valve 18 and via the drivetrain coolant radiator 32 back to the coolant pump 28. In the drivetrain coolant radiator 32, the waste heat of the drivetrain that has been absorbed in the electric motor heat exchanger 29 from the coolant circuit is released to the ambient air 33. The electric motor heat exchanger 29 is representative of components that are to be cooled by means of this coolant circuit, such as the electric motor, the power electronics or the DC-DC charger, for example.

After the evaporation of the refrigerant in the evaporators 10, 11, 12, the refrigerant circuit to the compressor 2 is closed via the low-pressure collector 13.

This operating mode is advantageous in order, aside from the active air-conditioning of the vehicle cabin by means of the refrigerant circuit switched so as to act as refrigeration installation, to also actively cool the battery in parallel with respect to the vehicle cabin by means of the refrigeration installation. By contrast, the drivetrain is not cooled by means of the refrigerant circuit in the refrigeration installation switching configuration, but rather is passively cooled exclusively by means of the ambient air 33.

In Figure 4, the switching configuration in the case of vehicle cabin cooling and possible additional air cooling of the second sub-circuit of the drivetrain coolant circuit has been implemented by switching. This mode is implemented by switching

- 19as an alternative if the ambient temperatures lie above 30 °C, as per temperature range E. The refrigerant sub-circuit is in a switching configuration similar to that in the mode described above. It is merely the case that the third evaporator, the chiller 12, is not supplied with refrigerant owing to the fully closed expansion element 9. The entire first sub-circuit of the drivetrain coolant circuit is not operated. However, in this mode, too, the second sub-circuit releases the waste heat of the drivetrain from the electric motor heat exchanger 29 via the 3-way valve 18 and via the drivetrain coolant radiator 32 to the ambient air 33.

The mode described here corresponds to that of a classic vehicle air-conditioning system. The air which is to be fed to the interior compartment of the vehicle, which may also include fractions of recirculated air, is cooled down and dried in order to lower the interior compartment temperature of the vehicle.

In the cabin cooling mode, only the interior compartment evaporators 10 and 11 are supplied with refrigerant. Here, the expansion element arranged upstream of the evaporator serves for the expansion of the refrigerant and for the required mass flow limitation, in accordance with demand.

Figure 5 illustrates the mode of active battery cooling. In this operating mode, the two evaporators 10 and 11 are shut off from the refrigerant circuit by means of fully closed expansion elements 7 and 8, such that the liquid refrigerant is entirely expanded via the expansion element 9 and evaporated in the chiller 12. The maximum active refrigeration power of the refrigerant circuit is thus available for the cooling of the battery by means of the battery cooler 25 in the first sub-circuit of the drivetrain coolant circuit. The second sub-circuit of the drivetrain coolant circuit is also switched into a parallel configuration with respect to said first part, and the waste heat of the drivetrain is released via the drivetrain coolant radiator 32 to the ambient air 33. Vehicle cabin cooling is dispensed with in particular in critical situations with regard to the battery temperature, for example in order to ensure maximum efficiency of the battery utilization and furthermore ensure the protection of the battery in critical thermal situations. This mode is implemented for example during the charging operation of the system at the charging station.

-20Figure 6 illustrates the switching configuration of the heat flow management device 1 in the reheating and passive battery cooling operating mode. The reheating mode is to be understood to mean that the air that is conducted to the vehicle cabin via the front-end air-conditioning unit 35 is firstly cooled and dehumidified in the front evaporator 10 and is subsequently warmed in the heating heat exchanger 19 to the desired outlet temperature from the front-end air-conditioning unit 35. This mode is required in the presence of mild ambient temperatures in the temperature range D, for example in order to prevent fogging of the windscreen in particular situations. The temperature range D extends approximately from 17 °C to 30 °C. The heat flow management device 1 is then operated with the refrigerant circuit such that the refrigerant, after being compressed in the compressor 2, flows through the indirect condenser 3, where, firstly, heat extraction after the compression of the refrigerant occurs. Here, the shut-off valve 14 is closed and the bypass 24 is inactive. The heat at relatively high temperature is transferred in the indirect condenser 3 to the heating section heat carrier circuit, and the heat carrier, a water-glycol mixture, is transported by means of the coolant pump 17 via the indirect condenser 3 to the heating heat exchanger 19, where the vehicle cabin air, after being cooled and dehumidified in the front evaporator 10, is then warmed to the corresponding desired temperature in the front-end air-conditioning unit 35. In the drivetrain coolant circuit, the battery and the drivetrain are duly conducted via the chiller 12, but this is not incorporated into the refrigerant circuit and therefore does not absorb any heat. The coolant is transported from the chiller 12 through the 3-way valve 26 via the electric motor heat exchanger 29 and through the 3-way valve 18 to the drivetrain coolant radiator 32, where the waste heat of the battery and of the drivetrain is released to the ambient air 33. From the drivetrain coolant radiator 32, the coolant flows onward via the coolant pump 28 and via the 3-way valves 27, 24 and the battery cooler 25 and the coolant pump 22 to the chiller 12, where the circuit is closed.

In the illustrated embodiment mode in Figure 6, the refrigerant circuit supplies liquid refrigerant only to the front evaporator 10, and the rear evaporator 11 for the rearend air-conditioning unit 36 and the chiller 12 are each excluded from the refrigerant circuit by means of closed expansion elements 9 and 8.

- 21 The heat that is extracted during the drying of the air by evaporation of the refrigerant is utilized again, by means of the condensation in the internal condenser 3, in order to heat the air back to the target temperature.

Here, depending on the ambient temperature, the surroundings heat exchanger 5 fitted in the front end of the vehicle can be controlled in closed-loop fashion in terms of its pressure level. Components of the electric drivetrain and the traction battery are passively cooled by means of coolant circuit and drivetrain coolant radiator 32.

Figure 7 shows the switching configuration of the heat flow management device 1 in the mode of efficient reheating with a single heat source. Here, the refrigeration circuit is illustrated with the compressor 2, the indirect condenser 3 and the expansion element 4 with throttling function. The surroundings heat exchanger 5 operates, after prior throttling of the refrigerant, as an evaporator in the heat pump mode of the refrigerant circuit, and absorbs ambient heat from the ambient air 33 for the purposes of evaporating the refrigerant. The refrigerant passes to the front evaporator 10 and, before this, is throttled once again in the expansion element 7. The front evaporator 10 thus substantially dehumidifies the air in the front-end airconditioning unit 35, which is subsequently warmed in the heating heat exchanger 19 to the correspondingly desired outlet temperature. The refrigerant vapour from the front evaporator 10 is fed via the low-pressure collector 13 to the compressor 2, and the refrigerant circuit is closed. The condensation of the refrigerant takes place in the indirect condenser 3, and the condensation heat is, in the heating section heat carrier circuit, conducted by means of the coolant pump 17 to the heating heat exchanger 19, where, as described, the air flow of the front-end air-conditioning unit 35 is correspondingly warmed by means thereof. The illustrated switching configuration is used in the temperature range C in the presence of low ambient temperatures which lie between 5 °C and 17 °C. Here, the drivetrain coolant circuit is operated without a further external heat source. The coolant circulates through the electric motor heat exchanger 29 via the 3-way valve 18 and the bypass 21, the coolant pump 28, the 3-way valves 27, 24 and via the battery cooler 25 and the coolant pump 22 and the chiller 12 to the electric motor heat exchanger 29. In this

- 22 mode, the chiller 12 is not flowed through by refrigerant. The waste heat of the drivetrain is thus utilized for the heating of the battery, without the involvement of an additional heat source.

In Figure 7, by contrast to the mode as per Figure 6, the surroundings heat exchanger 5 is operated as a heat source in the range between medium pressure and low pressure in order to be able to absorb the required energy.

Figure 8 illustrates a switching configuration in the case of efficient reheating and a double heat source. This mode is used in the temperature range C in the presence of low ambient temperatures. By contrast to the mode as per Figure 7, in the drivetrain coolant circuit, the battery cooler 25 is not operated and is not flowed through, whereas the chiller 12 is however operated as an evaporator by virtue of the expansion element 9 being opened. The drivetrain is thus actively cooled by means of the electric motor heat exchanger 29, and the heat absorbed from the refrigerant circuit can, by means of the indirect condenser 3, be absorbed from the heating section heat carrier circuit and released via the heating heat exchanger 19 to the air for the warming of the cabin.

By contrast to the above-described mode as per Figure 7, the drivetrain coolant circuit has now been switched such that, aside from the ambient heat, the waste heat of the electronic components, for example of the electric motor, of the power electronics and of the DC-DC charging unit, is also utilized for the heating of the vehicle cabin.

This heat pump mode is highly efficient and, owing to low electrical current consumption, increases the range of the electrically driven vehicle (EV HEV PHEV).

Figure 9 illustrates the switching configuration of the heat flow management device 1 in the case of vehicle cabin heating in the heat pump mode utilizing ambient heat, which is preferably implemented in the presence of cold and very cold ambient temperatures in the temperature ranges A and B between minus 20 °C and plus 5 °C. Here, the second sub-circuit of the drivetrain coolant circuit is switched so as

-23to include the electric motor heat exchanger 29, the bypass 21, the coolant pump 28 and the bypass 23, such that no additional heat source is used for the temperature control of the drivetrain. The refrigerant circuit comprises the compressor 2, the indirect condenser 3 for the condensation of the refrigerant and coupling-out of heat, and the expansion element 4 in a throttling position. The liquid, expanded refrigerant passes into the surroundings heat exchanger 5, which correspondingly operates as an evaporator in the heat pump switching configuration of the refrigerant circuit under the stated usage conditions. In this mode, the evaporators 10, 11 of the refrigerant circuit in the front-end air-conditioning unit 35 and in the rear-end air-conditioning unit 36 are not supplied with refrigerant. The chiller 12 is flowed through without throttling, such that, in this switching configuration, heat is absorbed from the ambient air 33 exclusively in the surroundings heat exchanger 5. The throttling and the complete evaporation of the refrigerant occur in the expansion element 4 and in the surroundings heat exchanger

5.

The above-described mode corresponds to the heat pump mode. The air blown into the interior compartment of the vehicle is not cooled down and is not dried. Instead, the heating heat exchanger 19 warms the interior compartment air. In order to provide the heat for this, the compressor 2 compresses gaseous refrigerant to a high pressure level. This is conducted through the indirect condenser 3, which functions as refrigerant condenser and provides a warm glycol-water mixture. In the front-end air-conditioning unit 35, the temperature valve opens up the path for the air through the heating heat exchanger 19. The refrigerant condenses at a high pressure level and, in so doing, releases heat to the heating section heat carrier circuit. The liquefied refrigerant thereafter passes at a high pressure level to the expansion element 4, which is set in accordance with the operating mode and in accordance with demand. From there, said refrigerant passes at a low pressure level to the surroundings heat exchanger 5. Here, the refrigerant is then changed from the liquid into the gaseous phase by means of evaporation without a direction reversal of the refrigerant circuit. The heat is absorbed entirely from the surroundings. Via the check valve 15, the refrigerant then passes to the further components.

- 24 Depending on the ambient temperature conditions or air temperatures in the interior compartment or the cooling demand of the electrical components, the following expansion elements 7, 8, 9 can then distribute the mass flow to the further evaporators 10, 11 and/or to the chiller 12.

In the specific mode as per Figure 9, the refrigerant passes only through the chiller 12, which itself is however shut off and not flowed through on the water-glycol side. Accordingly, the chiller functions here merely as a pipeline without evaporator function. The refrigerant thereafter passes to the low-pressure collector 13 and from there into the compressor 2.

The check valve 16 prevents a possible displacement of refrigerant into the evaporators 10, 11.

The heat pump mode is highly efficient and increases the purely electric range of the vehicle (EV HEV PHEV). A heating device 20, designed as a high-voltage heater HV-PTC, can assist the warming of the air in the air-conditioning unit yet further.

Figure 10 illustrates the switching configuration in the case of vehicle cabin heating utilizing the waste heat source, again in the presence of very cold and cold ambient temperatures between minus 20 °C and 5 °C.

The refrigerant circuit is switched so as to run from the compressor 2 via the indirect condenser 3 and, with the expansion element 4 closed, via the bypass 6 with shutoff valve, with throttling by means of the expansion element 9, and evaporation in the chiller 12, and accumulation in the low-pressure collector 13. The heating section heat carrier circuit utilizes the condensation heat from the indirect condenser 3, wherein the heat carrier is transported by means of the coolant pump 17 to the heating heat exchanger 19. The evaporators 10, 11 of the air-conditioning units 35, 36 are not active, because the air is also sufficiently dry in this temperature range. The drivetrain coolant circuit cools the drivetrain by means of the electric motor heat exchanger 29. The circuit is closed via the bypass 21, the coolant pump 28 and the

-25bypass 31 and the coolant pump 22 to the chiller 12, and the waste heat of the drivetrain is released via the chiller 12 to the indirect condenser 3 to the heating section heat carrier circuit.

By contrast to the previous mode as per Figure 9, no ambient heat is absorbed here, with the chiller 12 alone rather being used as evaporator for heat absorption for the refrigerant circuit. The waste heat from the electric drivetrain is sufficient here to realize the thermal comfort in the interior compartment.

Figure 11 illustrates the switching configuration of the heat flow management device 1 in the case of vehicle cabin heating utilizing the ambient heat and utilizing the waste heat of the drivetrain. In this operating mode, in the refrigerant circuit, in the presence of very cold and cold ambient temperatures between minus 20 °C and 5 °C in the temperature range A and B, after the compression of the refrigerant vapour in the compressor 2, condensation in the indirect condenser 3 and throttling of the refrigerant in the expansion element 4, the surroundings heat exchanger 5 is utilized as an evaporator for energy absorption from the ambient air 33. In the further course of the refrigerant circuit, the chiller 12 is also utilized, after throttling of the refrigerant in the expansion element 9, as an evaporator for the absorption of the waste heat from the drivetrain. The drivetrain coolant circuit is operated so as to run via the chiller 12, the electric motor heat exchanger 29 and via the bypass 21 and the coolant pump 28 and the bypass 31 to the chiller 12.

By contrast to the mode as per Figure 10, it is now the case both that ambient heat is extracted from the surroundings heat exchanger 5 and also that, via the chiller 12, waste heat is extracted from the electric drivetrain. In this mode, the battery is not cooled.

Figure 12 shows the switching configuration of the heat flow management device 1 in the case of battery conditioning by means of the waste heat from the drivetrain in use in the presence of very cold to cold ambient temperatures, as per the temperature range A and B, between minus 20 °C and 5 °C. Here, the refrigerant circuit and also the heating section heat carrier circuit are not operated. Only the

-26drivetrain coolant circuit is operated in the circuit from the electric motor heat exchanger 29 via the bypass 21, the coolant pump 28 and the battery cooler 25 and the coolant pump 22 and the chiller 12. However, since the refrigerant circuit is not operated, the chiller 12 does not cool the drivetrain coolant circuit in this operating mode, but is rather merely flowed through passively without heat transfer.

The illustrated mode serves for the battery preconditioning, in this case the battery pre-warming, for example in a standstill state during the charging of the battery. Electrical energy is converted into heat in a heating device within the drivetrain, and is transferred by means of the drivetrain coolant circuit to the traction battery.

This mode serves neither for heating nor cooling the interior compartment air.

If, in one of the above modes, the surroundings heat exchanger 5 superficially ices up owing to a malfunction or owing to overloading of the heating mode, the overall system loses heating power. To be able to reverse this again, the refrigerant circuit can be operated intermittently in a thawing mode. Here, the surroundings heat exchanger 5 is brought to a high pressure level despite a heating demand for the interior compartment. At said level, by means of condensation of the refrigerant in the surroundings heat exchanger 5, such an amount of heat is released to the latter such that the ice layer formed on the outside is thawed.

The following variants of the heat flow management device 1 as per Figure 13 and Figure 14 encompass the modes presented above and have been expanded to include further modes through the variation in the components.

Figure 13 illustrates a circuit diagram with an expanded radiator capacity. The heating section heat carrier circuit has been expanded to include a heat carrier cooling radiator 41. This is connected in parallel with respect to the heating heat exchanger 19, for which purpose a 3-way valve 42 is provided downstream of the indirect condenser 3 in the heating section heat carrier circuit. Thus, either the heat carrier cooling radiator 41 or the heating heat exchanger 19 can be operated or both can be operated proportionately.

- 27 It is however primarily possible for the heat carrier cooling radiator 41, in a cooling mode, to contribute to increased cooling power and efficiency.

A variant which is not illustrated consists in that an internal heat exchanger (IHX), also referred to as subcooling heat exchanger, is integrated into the refrigerant circuit. This leads to a reduction in the required compressor power in refrigeration installation operation. Furthermore, here, the relative cooling power of the interior compartment evaporator in relation to the chiller is effected in favour of interior compartment comfort without structural modification of the air-conditioning unit. The internal heat exchanger thus further increases the efficiency and furthermore lengthens the purely electric range of a PHEV, HEV, EV by reduction of the power demand of the electric compressor of the refrigerant circuit.

Figure 14 illustrates a circuit diagram with internal condenser, which is also referred to as heating condenser 43 and which is integrated by means of a 3-way valve 44 and a check valve 45 into the refrigerant circuit of the heat flow management device

1. In the case of this switching configuration, the heating section heat carrier circuit is replaced by the refrigerant loop formed downstream of the compressor 2 via the 3-way valve 44 to the heating condenser 43 and via the check valve 45 to the abovedescribed refrigerant circuit as per Figure 1.

In heating operation, the efficiency is increased through the omission of the outlay and the transfer losses owing to the heating section heat carrier circuit.

Finally, Figure 15 shows a diagram with an overview of the temperature ranges and the operating modes of the heat flow management device 1. Here, the temperature ranges are illustrated along a temperature scale beginning with A with the temperature range of very cold ambient temperatures from -20 °C to -8 °C, via the adjoining temperature range B of cold ambient temperatures up to 5 °C, via the temperature range C with low ambient temperatures up to 17 °C, to the temperature range D with mild ambient temperatures up to 30 °C, and finally to the temperature range E which comprises high ambient temperatures above 30 °C. The cabin

-28conditioning is to be assigned to the temperature ranges, with the heating cabin mode F in a temperature range between minus 20 °C and 5 °C. Furthermore, the reheat cabin mode G is correspondingly illustrated in the temperature range of 5 °C to 30 °C, and the cooling cabin operating mode H is illustrated in the temperature range of over 30 °C and upwards. Finally, the battery operating modes are also graded. The heating battery operating mode K is implemented from minus 20 °C to 0 °C. The passive cooling battery operating mode L lies between 0 °C and approximately 25 °C, and the active cooling battery operating mode M is present from 25 °C and upwards.

In accordance with demand, the refrigerant circuit can be adjusted in continuously variable closed-loop fashion between high pressure and low pressure to a medium pressure level, depending on whether heat is to be absorbed into the refrigerant circuit or released. This can be finely controlled in closed-loop fashion without, for example, the temperature of the interior compartment air decreasing significantly.

The described and illustrated heat flow management device 1, in particular in the heat pump switching configuration, offers enormous potential in relation to existing heat pumps with regard to possible operating modes with relatively low demand on components such as heat exchangers and expansion elements. Therefore, the heat flow management device 1 considerably increases the potential purely electric range of electrically driven vehicles, such as for example PHEV, HEV and EV with relatively low monetary outlay. The system can nevertheless be controlled in closedloop fashion in a highly effective manner and can thus operate optimally in all operating modes and in all possible ambient conditions and demand situations, such that the purely electric consumption during operation with the customer can be configured optimally.

Furthermore, a high-voltage water auxiliary heater is possibly used in order to selectively support the interior compartment comfort or warm the high-voltage battery. Both are necessary under certain circumstances in the presence of low ambient temperatures.

-29The technical advantages in relation to the prior art consist in a high level of waste heat utilization, wherein the heating power is considerably higher, because the suction density is higher owing to the higher suction pressure, and thus the refrigerant mass flow is higher. Economically, the system is advantageous in relation 5 to systems with an electrical auxiliary heater, because savings are obtained in relation to far more complex refrigeration circuit switching configurations.

-30List of reference designations

The heat flow management device

Compressor

Indirect condenser

Expansion element

Surroundings heat exchanger

Bypass with shut-off valve

Expansion element

Front evaporator

Rear evaporator

Chiller

Low-pressure collector

Shut-off valve

Check valve

Coolant pump

3-way valve

The heating heat exchanger

The heating device

Bypass

Coolant pump

Bypass

3-way valve

Battery cooler

3-way valve

Coolant pump

Electric motor heat exchanger

Bypass

Drivetrain coolant radiator

Ambient air

Bypass

Front-end air-conditioning unit

Rear-end air-conditioning unit

Air temperature sensor

Refrigerant temperature sensor

Refrigerant pressure and temperature sensor

Coolant temperature sensor

The heat carrier cooling radiator

3-way valve

The heating condenser

3-way valve

Check valve

A Temperature range of very cold ambient temperatures

B Temperature range of cold ambient temperatures

C Temperature range of low ambient temperatures

D Temperature range of mild ambient temperatures

E Temperature range of high ambient temperatures

F Cabin heating operating mode

G Cabin reheat operating mode

H Cabin cooling operating mode

K Battery heating operating mode

L Battery passive cooling operating mode

M Battery active cooling operating mode

Claims

1. A heat flow management device (1) for motor vehicles, having a refrigerant circuit, a drivetrain coolant circuit and a heating section heat carrier circuit, wherein:

the refrigerant circuit has a compressor (2), an indirect condenser (3), an expansion element (4), a surroundings heat exchanger (5), at least one evaporator (10,11) with associated expansion element (7, 8), and a chiller (12) with associated expansion element (9);

the drivetrain coolant circuit has a coolant pump (22), the chiller (12), an electric motor heat exchanger (29) and a drivetrain coolant radiator (32);

the heating section heat carrier circuit has a coolant pump (17), the indirect condenser (3) and a heating heat exchanger (19);

wherein the refrigerant circuit and the drivetrain coolant circuit are designed to be directly thermally coupled to one another by means of the chiller (12); and wherein the refrigerant circuit and the heating section heat carrier circuit are designed to be directly thermally coupled to one another by means of the indirect condenser (3), and the drivetrain coolant circuit and the heating section heat carrier circuit are thermally coupled to one another only indirectly by means of the refrigerant circuit.

2. The heat flow management device (1) according to Claim 1, characterized in that, in the refrigerant circuit, a bypass (34) with a shut-off valve (14) is arranged in parallel with respect to the indirect condenser (3).

3. The heat flow management device (1) according to Claim 1 or Claim 2, characterized in that, in the refrigerant circuit, two evaporators (10,11) are provided so as to be connected in parallel, wherein a front evaporator (10) is arranged in a front-end air-conditioning unit (35) and a rear evaporator (11) is arranged in a rearend air-conditioning unit (36).

4. The heat flow management device (1) according to Claim 3, characterized in that, in the refrigerant circuit, the evaporators (10, 11) are assigned separate

-33expansion elements (7, 8).

5. The heat flow management device (1) according to any one of Claims 1 to 4, characterized in that, in the refrigerant circuit, a low-pressure collector (13) for refrigerant is arranged upstream of the compressor (2).

6. The heat flow management device (1) according to any one of Claims 1 to 5, characterized in that, in the refrigerant circuit, an expansion element (4) is arranged upstream of the surroundings heat exchanger (5).

7. The heat flow management device (1) according to any one of Claims 1 to 6, characterized in that, in the refrigerant circuit, a bypass with shut-off valve (6) is arranged in parallel with respect to the surroundings heat exchanger (5) and the expansion element (4).

8. The heat flow management device (1) according to any one of Claims 1 to 7, characterized in that, in the drivetrain coolant circuit, there is arranged an additional coolant pump (28).

9. The heat flow management device (1) according to any one of Claims 1 to 8, characterized in that, in the drivetrain coolant circuit, a bypass (21) is arranged in parallel with respect to the drivetrain coolant radiator (32).

10. The heat flow management device (1) according to any one of Claims 1 to 9, characterized in that, in the drivetrain coolant circuit, in parallel with respect to the bypass (30), there is arranged a bypass (23) by means of which a sub-circuit with the electric motor heat exchanger (29), the drivetrain coolant radiator (32) and the additional coolant pump (28) can be formed.

11. The heat flow management device (1) according to any one of Claims 1 to 10, characterized in that, in the drivetrain coolant circuit, there is arranged a battery cooler (25).

12. The heat flow management device (1) according to Claim 11, characterized in that, in the drivetrain coolant circuit, a bypass (31) is arranged in parallel with respect to the battery cooler (25).

13. The heat flow management device (1) according to any one of Claims 1 to

12, characterized in that, in the drivetrain coolant circuit, in parallel with respect to the bypass (23), there is arranged a bypass (30) by means of which a sub-circuit with the chiller (12), the battery cooler (25) and the coolant pump (22) can be formed, and the drivetrain coolant circuit is designed to be operable in two separately and mutually independently operable sub-circuits.

14. The heat flow management device (1) according to any one of Claims 1 to

13, characterized in that, in the front-end air-conditioning unit (35), in addition to the heating heat exchanger (19), there is arranged an additional heating device (20).

15. The heat flow management device (1) according to Claim 14, characterized in that, as an additional heating device (20), a PTC heating element is arranged in the front-end air-conditioning unit (35).

16. The heat flow management device (1) according to any one of Claims 1 to 15, characterized in that an open-loop and closed-loop control device is formed, wherein, in the refrigerant circuit, in each case one refrigerant pressure and temperature sensor (39) is arranged downstream of the compressor (2), downstream of the surroundings heat exchanger (5) and downstream of the chiller (12), and, in the refrigerant circuit, a refrigerant temperature sensor (38) is arranged downstream of the evaporator (10), and, in the drivetrain coolant circuit, in each case one coolant temperature sensor (40) is arranged upstream of the coolant pump (28), upstream of the coolant pump (22) and downstream of the chiller (12) and an air temperature sensor (37) is arranged in the air stream downstream of the front evaporator (10), downstream of the heating device (20), downstream of the rear evaporator (11) and upstream of the surroundings heat exchanger (5).

17. The heat flow management device (1) according to any one of Claims 1 to

-3516, characterized in that, in the heating section heat carrier circuit, a heat carrier cooling radiator (41) is, by means of a 3-way valve (42), arranged in parallel with respect to the heating heat exchanger (19).

18. The heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in the refrigerant circuit, downstream of the compressor (2), a heating condenser (43) is arranged in a line loop, which can be shut off by means of a 3-way valve (44), so as to be switchable into a series configuration with respect to the surroundings heat exchanger (5).

19. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in a temperature range E in the presence of high ambient temperatures, for the purposes of cabin and active battery cooling, the drivetrain coolant circuit is operated in two sub-circuits, wherein the first sub-circuit is switched so as to be composed of the chiller (12), the bypass (30), the battery cooler (25) and the coolant pump (22), and the second sub-circuit is switched so as to be composed of the drivetrain coolant radiator (32), the coolant pump (28), the bypass (23) and the electric motor heat exchanger (29), and the refrigerant circuit is switched so as to comprise the compressor (2), the bypass (34) with open shut-off valve (14), the surroundings heat exchanger (5), and the chiller (12), front evaporator (10) and rear evaporator (11) connected in parallel.

20. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in a temperature range E in the presence of high ambient temperatures, for the purposes of cabin cooling, the drivetrain coolant circuit is switched so as to comprise the first sub-circuit composed of the chiller (12), the bypass (30), the battery cooler (25) and the coolant pump (22), and the refrigerant circuit is switched so as to comprise the compressor (2), the bypass (34) with open shut-off valve (14), the surroundings heat exchanger (5), and the front evaporator (10) and rear evaporator (11) connected in parallel.

21. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in a temperature range E in the

-36presence of high ambient temperatures, for the purposes of active battery cooling, the drivetrain coolant circuit is operated in two sub-circuits, wherein the first subcircuit is switched so as to be composed of the chiller (12), the bypass (30), the battery cooler (25) and the coolant pump (22), and the second sub-circuit is switched so as to be composed of the drivetrain coolant radiator (32), the coolant pump (28), the bypass (23) and the electric motor heat exchanger (29), and the refrigerant circuit is switched so as to comprise the compressor (2), the bypass (34) with open shut-off valve (14), the surroundings heat exchanger (5) and the chiller (12).

22. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in a temperature range D in the presence of mild ambient temperatures, for the purposes of reheating and for the purposes of passive battery cooling, the drivetrain coolant circuit is switched so as to be composed of the chiller (12), the electric motor heat exchanger (29), the drivetrain coolant radiator (32), the coolant pump (28), the battery cooler (25) and the coolant pump (22), and the heating section heat carrier circuit is switched so as to comprise the coolant pump (17), the indirect condenser (3) and the heating heat exchanger (19), and the refrigerant circuit is switched so as to comprise the compressor (2), the indirect condenser (3), the surroundings heat exchanger (5) and the front evaporator (10).

23. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in a temperature range C in the presence of low ambient temperatures, for the purposes of efficient reheating, the drivetrain coolant circuit is switched so as to be composed of the chiller (12), the electric motor heat exchanger (29), the bypass (21), the coolant pump (28), the battery cooler (25) and the coolant pump (22), and the heating section heat carrier circuit is switched so as to comprise the coolant pump (17), the indirect condenser (3) and the heating heat exchanger (19), and the refrigerant circuit is switched so as to comprise the compressor (2), the indirect condenser (3), the expansion element (4) , the surroundings heat exchanger (5) as evaporator for heat absorption, and the front evaporator (10).

24. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in a temperature range C in the presence of low ambient temperatures, for the purposes of efficient reheating and for the purposes of active battery and drivetrain cooling, the drivetrain coolant circuit is switched so as to be composed of the chiller (12), the electric motor heat exchanger (29), the bypass (21), the coolant pump (28), the battery cooler (25) and the coolant pump (22), and the heating section heat carrier circuit is switched so as to comprise the coolant pump (17), the indirect condenser (3) and the heating heat exchanger (19), and the refrigerant circuit is switched so as to comprise the compressor (2), the indirect condenser (3), the expansion element (4), the surroundings heat exchanger (5) as evaporator for heat absorption, and the chiller (12) and front evaporator (10) connected in parallel.

25. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in temperature ranges A and B in the presence of, respectively, very cold and cold ambient temperatures, for the purposes of cabin heating, the drivetrain coolant circuit is switched so as to comprise the electric motor heat exchanger (29), the bypass (21), the coolant pump (28) and the bypass (23), and the heating section heat carrier circuit is switched so as to comprise the coolant pump (17), the indirect condenser (3) and the heating heat exchanger (19), and the refrigerant circuit is switched so as to comprise the compressor (2), the indirect condenser (3), the expansion element (4), the surroundings heat exchanger (5) as evaporator for heat absorption, and the chiller (12).

26. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in temperature ranges A and B in the presence of, respectively, very cold and cold ambient temperatures, for the purposes of cabin heating with waste heat, the drivetrain coolant circuit is switched so as to comprise the chiller (12), the electric motor heat exchanger (29), the bypass (21), the coolant pump (28), the bypass (31) and the coolant pump (22), and the heating section heat carrier circuit is switched so as to comprise the coolant pump (17), the indirect condenser (3) and the heating heat exchanger (19), and the

-38refrigerant circuit is switched so as to comprise the compressor (2), the indirect condenser (3), the expansion element (4), the bypass with shut-off valve (6), the expansion element (9) and the chiller (12).

27. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in temperature ranges A and B in the presence of, respectively, very cold and cold ambient temperatures, for the purposes of cabin heating with waste heat and ambient heat, the drivetrain coolant circuit is switched so as to comprise the chiller (12), the electric motor heat exchanger (29), the bypass (21), the coolant pump (28), the bypass (31) and the coolant pump (22), and the heating section heat carrier circuit is switched so as to comprise the coolant pump (17), the indirect condenser (3) and the heating heat exchanger (19), and the refrigerant circuit is switched so as to comprise the compressor (2), the indirect condenser (3), the expansion element (4), the surroundings heat exchanger (5) as evaporator for heat absorption, the expansion element (9) and the chiller (12).

28. A method for operating a heat flow management device (1) according to any one of Claims 1 to 16, characterized in that, in temperature ranges A and B in the presence of, respectively, very cold and cold ambient temperatures, for the purposes of battery preconditioning with waste heat, the drivetrain coolant circuit is switched so as to comprise the chiller (12), the electric motor heat exchanger (29), the bypass (21), the coolant pump (28), the battery cooler (25) and the coolant pump (22).