The invention relates to a heating, ventilation and/or air conditioning unit for a car.

Heating, ventilation and/or air conditioning units are designed to generate one or more temperature-controlled air streams. In cars, such units are used for the aeration and air conditioning of a vehicle interior. Here, it is commonly possible for variable air streams, which may each have a different temperature, to be fed to different regions of the vehicle interior. In order to adjust whether and how much air is fed to a region, the air streams to different regions of the vehicle interior can be selectively blocked or allowed.

In a heating, ventilation and/or air conditioning unit, a cold air stream is generally available downstream of an evaporator, a proportion of which cold air stream is branched off and warmed by means of a heat exchanger. In this way, a cold air stream and a warm air stream which is separate from said cold air stream are obtained. In order for an air stream for the air conditioning of the vehicle interior to be brought to a desired temperature, the two air streams can be mixed in a predefined mixing ratio.

In order to improve comfort for one or more vehicle occupants, it is desirable for a vehicle occupant to be able to set the temperature for different regions of the vehicle interior to a desired temperature in a particularly exact manner. Furthermore, it is sought for the respective volume flows to the individual regions of the vehicle interior to be adjustable, or capable of being blocked entirely, independently of one another.

It is therefore an object of the invention to provide a heating, ventilation and/or air conditioning unit with which the temperature and a feed of air in different regions of the vehicle interior can be individually adjusted.

Said object is achieved according to the invention by means of a heating, ventilation and/or air conditioning unit for a car, having a first air guide for guiding a first, cold air stream and having a second air guide for guiding a second, warm air stream which is separate from the first air stream, and having a first mixing chamber, wherein the first and the second air guide open into the first mixing chamber, and having a second mixing chamber, wherein the first mixing chamber and the second air guide each have an inlet opening to the second mixing chamber. At the two inlet openings, there is arranged in each case one flap which is mounted so as to be movable between an open position and a closed position in order to selectively open or close the inlet openings.

By means of the heating, ventilation and/or air conditioning unit according to the invention, the cold air stream and the warm air stream can be mixed in the first mixing chamber in order to generate a first mixed air stream. The mixed air stream and at least a proportion of the warm air stream can in turn be mixed with one another in the second mixing chamber. In this way, it is possible to generate two differently temperature-controlled air streams. By virtue of in each case one movably mounted flap being arranged at the two inlet openings to the second mixing chamber, it is possible according to the invention for the mixing ratio of warm air and mixed air in the second mixing chamber to be set in a particularly flexible manner, in particular through corresponding adjustment of the two flaps. Furthermore, in addition to the mixing ratio, it is also possible for a volume flow out of the second mixing chamber to be adjusted.

For example, both flaps can be opened to a maximum extent, or at least one, in particular both flaps may each be only partially opened, such that a volume flow out of the second mixing chamber is smaller than in the case of a maximally opened position of the two flaps. In a further scenario, both flaps may be closed if the second mixing chamber is not required. In the closed state of the flaps, the inlet openings are completely closed, such that, aside from a small leakage stream, no air can flow through the inlet opening. This has the advantage that the heating, ventilation and/or air conditioning unit is particularly energy-efficient. In particular, the flow paths of the warm air stream and of the mixed air stream can be simultaneously set particularly flexibly in a desired manner.

The air guides are for example in the form of channels which are circumferentially closed at least in certain sections.

The second mixing chamber preferably leads to a vehicle interior, specifically in particular to a footwell. More specifically, the second mixing chamber may have an outlet opening which is separate from the inlet openings and via which air can flow from the second mixing chamber into the vehicle interior. By virtue of the fact that, at the two inlet openings, there is arranged in each case one movably mounted flap which can close the inlet openings, it is possible for a further flap at the outlet opening of the second mixing chamber to be omitted.

In one embodiment, the two flaps are kinematically coupled to one another, for example by means of a transmission mechanism, in particular a cam mechanism. In this way, the two flaps can be moved by means of a single drive, in particular from the open position into the closed position and vice versa.

Preferably, the two flaps are kinematically coupled to one another such that the two flaps can close the inlet openings to the second mixing chamber simultaneously. A position of the flaps can be controlled particularly easily by means of such a kinematic coupling.

More specifically, the two flaps may be kinematically coupled to one another such that the flaps are movable with one another oppositely in linear fashion or are movable with one another oppositely in non-linear fashion. This is possible through corresponding design of the cam track of the cam mechanism. Such a coupling has the advantage that the setting of the flap positions relative to one another can be performed within certain specifications. This means that the setting possibilities for the two flaps relative to one another can be restricted, specifically such that only setting possibilities which are expedient from an energy aspect are allowed.

According to a further embodiment, the two flaps are movable independently of one another, in particular by means of in each case one actuator. In this way, the position of each flap can be set in a particularly flexible manner. In particular, in this way, any desired ratio of warm air to mixed air can be set in the second mixing chamber.

In addition to the two flaps at the inlet openings to the second mixing chamber, a further flap, in particular a cold-air flap, may be arranged in the first air guide and/or a further flap, in particular a warm-air flap, may be arranged in the second air guide, in order to adjust the air stream through the associated air guide. By means of the two further flaps, the temperature of the mixed air that has been mixed in the first mixing chamber can be set through corresponding control of the flap position. The warm-air flap and the cold-air flap can preferably completely close the associated air guide.

In order to generate a warm air stream, the heating, ventilation and/or air conditioning unit preferably has a heating device which is arranged at least partially in the second air guide. The heating device is for example a heat exchanger. By means of a heat exchanger, the waste heat of an engine can be utilized to warm the air stream, such that the heating, ventilation and/or air conditioning unit is particularly energy-efficient. Alternatively or in addition, it is also possible for an electric heating element to be provided in order to heat the warm air stream particularly quickly. It is thus possible for a warm air stream to be immediately generated even directly after a cold start.

In one embodiment, the first air guide is led past the heating device and, downstream of the heating device, opens directly into the first mixing chamber. By means of such an arrangement of the cold-air flap, the first air guide is particularly short and opens into the first mixing chamber immediately downstream of the division of the two air streams. This contributes to a compact design of the heating, ventilation and/or air conditioning unit.

The further flap of the first air guide may in this case, in particular in relation to the flow direction of the cold air stream, be situated to the side of the heating device and define the opening to the first mixing chamber. This likewise contributes to a compact design of the heating, ventilation and/or air conditioning unit.

The further flap of the second air guide is situated for example upstream of the heating device. In this way, in the closed state of the warm-air flap, no warm air stream whatsoever is generated, such that only a cold air stream is available in the heating, ventilation and/or air conditioning unit. Such a setting is advantageous if the vehicle interior is to be warmed no further, or is to be cooled.

Furthermore, the heating, ventilation and/or air conditioning unit may have an evaporator, wherein the first and the second air guide are arranged downstream of the evaporator. By means of the evaporator, the air can firstly be cooled before it enters the air guides. In particular, at the evaporator, an overall air stream is cooled to the temperature of the cold air stream. Said overall air stream can then be divided into the first and the second air guide. In one embodiment, the first mixing chamber has at least one outlet opening which leads to a vehicle interior. In this way, the temperature-controlled mixed air can be fed to the vehicle interior for the ventilation and temperature control thereof. For example, in each case one outlet opening to a windscreen, to a front seat, in particular to a driver's seat and a front passenger seat and/or to a rear seat bench may be provided.

At the at least one outlet opening, there is preferably likewise arranged a flap which is mounted so as to be movable between an open position and a closed position and which can close the associated outlet opening as required if no air stream is required in a vehicle region associated with the outlet opening.

More specifically, the first mixing chamber may have separate channels to different interior regions, which channels are each closable by means of a dedicated flap.

The first air guide, the second air guide, the first mixing chamber and/or the second mixing chamber may be formed in a common housing. In this way, the heating, ventilation and/or air conditioning unit is of particularly compact form. Furthermore, in this way, the outlay for the assembly of the unit can be kept low. The housing is for example made up of multiple shells which are to be connected to one another.

The first air guide and the second air guide may in this case have a common partition at least in certain sections. This likewise contributes to a compact design of the unit.

The heating device and/or the evaporator are preferably likewise accommodated in the common housing. This contributes to a compact design of the heating, ventilation and/or air conditioning unit.

In order to set the position of all of the abovementioned flaps, the heating, ventilation and/or air conditioning unit may have an electronic control device which is designed to control the position of the movably mounted flaps. It is thus possible for a temperature profile desired by a vehicle occupant to be set in the vehicle interior. Further advantages and features of the invention will emerge from the following description and from the appended drawings, to which reference is made. In the drawings:

Figure 1 shows a heating, ventilation and/or air conditioning unit according to the invention in a schematic sectional illustration,

Figure 2 shows a diagram for illustrating a kinematic coupling of two flaps of the heating, ventilation and/or air conditioning unit from Figure 1 , and

Figure 3 shows a diagram for illustrating an alternative kinematic coupling of two flaps of the heating, ventilation and/or air conditioning unit from Figure 1.

Figure 1 shows a heating, ventilation and/or air conditioning unit 10 according to the invention for a car in a schematic sectional illustration. The heating, ventilation and/or air conditioning unit 10 serves for the aeration and air conditioning of a vehicle interior.

The heating, ventilation and/or air conditioning unit 10 has a housing 12, which is preferably manufactured from plastic.

The housing 12 has an inlet opening 14 and multiple outlet openings 16, 17, 18, which lead to various air diffusers distributed in the interior.

An evaporator 20 is arranged in the region of the inlet opening 14. More specifically, the evaporator 20 is arranged in the housing 12.

Downstream of the inlet opening 14 and downstream of the evaporator 20, the air guide channel 21 divides into a first air guide 22 for guiding a first, cold air stream and a second air guide 24 which is separate from said first guide and which serves for guiding a second, warm air stream in the housing 12. The first air guide 22 may also be referred to as cold-air guide, and the second air guide 24 may be referred to as warm-air guide.

The air guides 22, 24 are formed at least in certain sections as channels and/or are formed at least in certain sections by walls of the housing 12, along which the cold air stream and/or warm air stream can flow. A heating device 26, more specifically a heat exchanger, is arranged in the second air guide 24. The heating device 26 is likewise arranged in the housing 12.

Instead of a heat exchanger or in addition to this, the heating device 26 may also comprise an electric heating element.

The heating device 26 is dimensioned so as to completely fill a flow cross section of the second air guide 24 at the position at which the heating device 26 is arranged, aside from manufacturing-induced gaps in the peripheral region. This means that the entirety of the second, warm air stream must flow through the heating device 26.

The heating, ventilation and/or air conditioning unit 10 furthermore comprises a first mixing chamber 28 and a second mixing chamber 30. The two mixing chambers 28, 30 are likewise formed in the housing 12 but are separate from one another.

The first air guide 22 and the second air guide 24 both open into the first mixing chamber 28. Here, the first air guide 22 is led past the heating device 26 and opens directly into the first mixing chamber 28 downstream of the heating device 26.

The second air guide 24 furthermore has an inlet opening 32 to the second mixing chamber 30. In other words, the second air guide 24 has a branch to the second mixing chamber 30. Here, the inlet opening 32 is formed in a common wall 36 of the second air guide 24 and of the second mixing chamber 30.

Furthermore, the first mixing chamber 28 has an inlet opening 34 to the second mixing chamber 30.

Of the outlet openings 16, 17, 18, two outlet openings 16, 17 are formed in the first mixing chamber 28 and one outlet opening 18 is formed in the second mixing chamber 30.

The two outlet openings 16, 17 lead for example to different front regions in a vehicle interior, such as a windscreen and a front seat, and conduct mixed air to said regions from the first mixing chamber 28. In particular, the first mixing chamber 28 has separate channels 35, 37 to different interior regions. For example, the outlet opening 18 leads to a footwell and conducts mixed air to said footwell from the second mixing chamber 30.

The second mixing chamber 30 has a smaller volume than the first mixing chamber 28, because a smaller volume flow is required for air conditioning in a footwell of the car than in the other regions of the vehicle interior.

It is optionally possible for yet further outlet openings to be provided if a yet further subdivision of the mixed air streams is desired.

In order to adjust the distribution of all air streams in the housing 12 and the feed of the mixed air streams to the vehicle interior, multiple movably mounted flaps 38, 40, 42, 44, 46, 48 are provided in the housing.

At the two inlet openings 32, 34 to the second mixing chamber 30, there is arranged in each case one flap 38, 40 which is mounted so as to be movable between an open position and a closed position in order to selectively open or close the inlet openings 32, 34.

When the flap 38 is closed, the two mixing chambers 28, 30 are separated from one another in terms of flow.

In one embodiment, the two flaps 38, 40 may be kinematically coupled to one another, for example by means of a mechanism, for example a cam mechanism 50. The mechanism may have a constant or a varying transmission ratio. Accordingly, both flaps 38, 40 can be moved simultaneously through the actuation of a camshaft 52. The cam mechanism 50 is illustrated purely schematically in Figure 1.

In particular, the two flaps 38, 40 are kinematically coupled to one another such that the two flaps 38, 40 can close the inlet openings 32, 34 to the second mixing chamber 30 simultaneously.

Here, the flaps 38, 40 may be movable with one another oppositely in linear fashion or movable with one another oppositely in non-linear fashion. This is possible through corresponding design of the cam track of the cam mechanism 50. In an alternative embodiment, the two flaps 38, 40 may be movable entirely independently of one another. In this case, it is preferable for each of the two flaps 38, 40 to be assigned a symbolically illustrated actuator 41 , 41'.

Furthermore, a flap 42, also referred to as cold-air flap, is arranged in the first air guide 22. As viewed in a flow direction, the flap 42 is situated to the side of the heating device 26 and defines the opening to the first mixing chamber 28.

Furthermore, a flap 44, also referred to as warm-air flap, is arranged in the second air guide 24. The flap 44 of the second air guide 24 is situated upstream of the heating device 26. Both the cold-air flap 42 and the warm-air flap 44 are movable from an open position into a closed position in order to adjust the air stream through the associated air guide 22, 24. In the closed position of the flap 42, 44, an air stream through the associated air guide 22, 24 is preferably blocked completely, aside from small leakage streams. The flaps 46, 48 are arranged at the outlet openings 16, 17 and can be moved from an open position into a closed position in order to adjust or completely block an air stream through the outlet openings 16, 17 to the vehicle interior.

A further flap at the outlet opening 18 can be omitted, because an air stream through the outlet opening 18 can already be blocked by means of the flaps 38, 40.

The flaps 38, 40, 42, 44, 46, 48 are exclusively so-called two-limb flaps, that is to say the flaps 38, 40, 42, 44, 46, 48 have two limbs which intersect at the centre of rotation and which extend to both sides beyond the centre of rotation by a similar or equal length. Such a form of the flaps 38, 40, 42, 44, 46, 48 has the advantage that a torque acting on the flaps 38, 40, 42, 44, 46, 48 as a result of an air flow is considerably lower than that in the case of a single-limb flap. In particular, the resultant torque may be approximately zero. It is however also conceivable for one or more flaps to be designed as single-limb flaps.

In Figure 1 , the flaps 38, 40, 42, 44, 46, 48 are illustrated in each case in a closed position. For illustrative purposes, an open position of the flaps 38, 40, 42, 44, 46, 48 is additionally illustrated by dashed lines. Below, the functioning of the heating, ventilation and/or air conditioning unit 10 will be discussed on the basis of Figure 1. Here, the various air streams are illustrated by arrows for the purposes of improved understanding.

When the heating, ventilation and/or air conditioning unit 10 is in operation, air flows through the inlet opening 14 into the housing 12. Here, the air stream flows through the evaporator 20, such that a cold overall air stream is generated.

This overall air stream can, in a manner dependent on the position of the flaps 42, 44, be divided into the first, cold air stream and the second, warm air stream. In this case, the two flaps 42, 44 must be opened at least partially such that air can flow into the first air guide 22 and into the second air guide 24.

Here, the temperature of the cold air stream corresponds to the temperature of the overall air stream. The warm air stream is generated by virtue of that part of the overall air stream which passes into the second air guide 24 flowing through the heating device 26 and, in the process, absorbing heat.

Subsequently, the cold air stream and at least a proportion of the warm air stream can flow into the first mixing chamber 28, wherein, in the mixing chamber 28, the two air streams that have entered are merged again and thoroughly mixed. The temperature of the mixing air in the first mixing chamber can in this case be set to a desired temperature through corresponding adjustment of the respective volume of the warm air stream and of the cold air stream.

The temperature-controlled mixed air from the mixing chamber 28 can subsequently be fed via the outlet openings 16, 17 to the vehicle interior, if the flaps 46, 48 are at least partially open, for the purposes of air conditioning of the associated regions of the vehicle interior.

Additionally, mixed air can be generated in the second mixing chamber 30 by virtue of mixed air from the first mixing chamber 28 being fed to the second mixing chamber 30 via the inlet opening 34 and, additionally, warm air being branched off from the second air guide 24 and fed to the second mixing chamber 30 via the inlet opening 32. It is thus possible, in the second mixing chamber 30, for mixed air to be generated which has a temperature which differs from the temperature generated in the first mixing chamber 28, wherein, in particular, the mixed air generated in the second mixing chamber 30 is warmer than the mixed air generated in the first mixing chamber 28.

The mixed air from the second mixing chamber 30 can be fed via the outlet opening 18 to a further region of the vehicle interior, in particular the footwell.

The second mixing chamber 30 however does not imperatively need to be utilized to generate mixed air. If the flap 38 is completely closed and the flap 40 is at least partially open, exclusively warm air from the second air guide 24 is fed to the second mixing chamber 30, that is to say no mixing of air occurs. In this case, the second mixing chamber 30 serves merely as an air guide.

Alternatively, it is possible for only mixed air from the first mixing chamber 28 to be fed to the second mixing chamber 30 if the flap 40 is completely closed and the flap 38 is at least partially open.

As a further alternative, the two flaps 38, 40 can both be completely closed. In this case, only the first mixing chamber 28 is used, and in this case the second mixing chamber 30 is inactive.

In the same way, with corresponding flap positioning, the first mixing chamber 28 can also serve merely as an air guide.

Figure 2 illustrates the kinematic coupling of the two flaps 38, 40 on the basis of a diagram. Here, the flaps 38, 40 are coupled to one another oppositely in linear fashion, which means that, as the flap 38 closes, the flap 40 opens.

In the diagram, for improved understanding, the curves associated with the respective flaps 38, 40 are denoted by the corresponding reference designations of the flaps 38, 40.

A degree of opening of the flaps 38, 40 is plotted on the ordinate, wherein the flaps 38, 40 are open to a maximum extent at the value 100, and are completely closed at 0.

The rotational angle of the camshaft 52, which is a constituent part of the cam mechanism 50 for the drive of the flaps 38, 40, is plotted on the abscissa.

In the initial state, the flap 38 which is arranged at the inlet opening 34 from the first mixing chamber 28 to the second mixing chamber 30 is open to a maximum extent, whereas the flap 40 which is arranged at the inlet opening 32 of the second air guide 24 to the second mixing chamber is completely closed.

During a rotation of the camshaft, the flap 38 closes while the flap 40 simultaneously opens to an equal extent, until, at 80% of the maximum range of rotation of the camshaft, the flap 40 is open to a maximum extent, whereas the flap 38 is completely closed.

If the camshaft rotates further, the flap 40 closes again, such that, if the camshaft rotates to 100% of the maximum range of rotation, both flaps 38, 40 are closed. Figure 3 illustrates, on the basis of a further diagram, opposite non-linear coupling of the two flaps 38, 40 to one another. In the case of such coupling, the gradient of the closing curves of the flaps 38, 40 varies.

Such non-linear coupling with varying transmission ratios of the movements of the flaps 38, 40 is possible by means of a corresponding design of a cam track of the cam mechanism 50. By contrast to a linear coupling, in the case of which the gradient of the cam track is constant, the gradient of the cam track varies in the case of a non-linear coupling.

The same can self-evidently also be realized by means of the actuators 41 , 41' which receive commands from an electronic controller.