Air conditioning unit, in particular for a motor vehicle air conditioning system

Abstract

Air conditioning device (20), in particular for a motor vehicle air conditioning system, comprising - an air-conducting housing (1, 2, 11) with at least one air inlet part (1), at least one air outlet part (2) and a diffuser housing (11) arranged therebetween, - a blower unit (5) arranged in the air-conducting housing (1, 2, 11) with a fan wheel (3) and a fan motor (4) and - a cooling device (6) with an air inlet surface (9) facing the blower unit (5), and a heating device (8) arranged downstream therefrom, both of which are arranged downstream of the blower unit (5) in the air-guiding housing (1, 2, 11), characterized in that an air filter (10) is arranged between the blower unit (5) and the cooling device (6) and the blower unit (5) is aligned relative to the cooling device (6) such that the extension of the axis of rotation (12) of the fan wheel (3) intersects the air inlet surface (9) of the cooling device (6).

Description

[0001] The present invention relates to an air conditioning unit, in particular for a motor vehicle air conditioning system. Air conditioning units of this type are well known and comprise an air-conducting housing with an air inlet and one or more air outlets, as well as a fan arranged in the air-conducting housing. They further comprise a cooling device and at least one first heating device arranged downstream therefrom, both of which are typically arranged downstream of the fan in the air-conducting housing. The cooling and heating devices are typically designed as heat exchangers, with evaporators being used as the cooling device and water heat exchangers or electrical auxiliary heaters known as PTC elements being used as the heating device.

[0002] Due to the typical fan requirements in automotive engineering regarding air volume flow, air-side pressure increase, acoustics and production costs, radial fans with forward-curved blades are primarily used as blowers.

[0003] Commonly used radial fans accelerate the air radially to the rotational axis of the fan impeller into a diffuser housing, where the cross-section increases orthogonally to the air flow, thereby building up pressure. The dimensions of this volume are determined according to fluid mechanics based on the functional target values ​​for the air flow rate and pressure buildup.

[0004] The demands of automotive engineering, and particularly those of a vehicle's cockpit, also affect the air conditioning system. Therefore, future vehicle generations must consider one or more of the following features: - An increasing number of additional features are required in the cockpit, such as head-up displays and driver assistance systems. These features require additional installation space and / or flexible installation space design in the cockpit. - A general reduction in costs and weight is desirable. - Due to increasingly quieter engines, especially the use of electric motors, but also due to an increasing need for comfort, it is important to ensure that the air conditioning unit is as quiet as possible. - In order to reduce primary energy requirements, particularly for reasons of reducing emissions and increasing range while maintaining the same level of comfort and performance, air conditioning systems that are as energy-efficient as possible must be developed. - In the course of reducing emissions and costs throughout the entire product development process, the reduction of installation space volume and weight should continue to be sought in order to also reduce, for example, costs and emissions of logistics processes.

[0005] The radial inflow into the diffuser housing in conjunction with the functional and space-related requirements of a vehicle limits the degrees of freedom of arrangement of the fan blower in relation to the heat exchangers.

[0006] The use of an electric fan motor as a drive for an air conditioning unit as described above generally requires active air cooling of the electronic components. The required cooling air flow is extracted from one side of the diffuser inlet or downstream and guided via a cooling air duct to the fan motor's control electronics. In conventional arrangements, this air extraction influences the expansion process, for example, by creating vortices.

[0007] It is the object of the present invention to design an air conditioning device of the type mentioned at the outset in such a way that one or more of the above-mentioned problems are alleviated and the above-mentioned requirements are taken into greater consideration.

[0008] This object is achieved according to the invention by an air conditioning device according to claim 1. Advantageous developments and further developments emerge from the dependent claims.

[0009] The air conditioning unit according to the invention is characterized in that an air filter is arranged between the blower unit and the cooling device, and the blower unit is aligned relative to the cooling device such that the projection of the rotational axis of the fan wheel intersects the air inlet surface of the cooling device. This promotes a straight inflow, whereby the downstream components located in the air flow are supplied with air more efficiently. Advantageously, the projection of the rotational axis is aligned such that it intersects the air inlet surface of the cooling device in the center. This also enables a compact design. "Central" in the sense of the invention includes not only the geometric center of the air inlet surface, but also any point near the center that is closer to the center than any point on one of the edge regions.

[0010] It has been found that such an arrangement can generate an effective airflow with comparatively low noise, especially when a radial blower with a fan wheel featuring backward-curved blades is selected as the blower unit. Although radial blowers with backward-curved blades have been known as such for decades (reference is made here to EP 0 112 932 A1 as an example), their application in automotive air conditioning systems has so far received insufficient attention.

[0011] JP 2019- 69 753 A and DE 11 2015 000 983 T5 show further state of the art.

[0012] Advantageously, the blower unit is integrated into the diffuser housing, with the diffuser housing preferably tapering in cross-section downstream and completely enclosing the blower unit. This allows for an even more compact design. The distance between the blower unit and the air filter located upstream can be further reduced. Tests have shown that this distance can be less than 10 cm, preferably even less than 5 cm.

[0013] Advantageously, air guiding means are provided in front of the diffuser housing, allowing the diffuser housing to receive a circular flow (i.e., a full 360° around the fan wheel). The fan motor can advantageously be located downstream of the fan wheel, in which case the cooling air can be extracted at the downstream end of the diffuser housing. This optionally eliminates the need for a separate cooling air duct for cooling the fan motor, which improves the acoustic properties of the air conditioning unit.

[0014] The invention will now be described using an embodiment and with reference to the Fig. 1 is explained in more detail.

[0015] In the Fig. Figure 1 schematically illustrates the structure of an air conditioning unit 20 according to the exemplary embodiment of the invention. The air conditioning unit 20 comprises an airtight air-conducting housing with an air inlet housing (air inlet part) 1 and an air outlet housing (air outlet part) 2 and is made of a hard plastic, e.g., polypropylene. The air inlet housing 1 has a flap arrangement 13 that regulates the air supply from various air sources, in particular ambient air and recirculated air. The air outlet housing 2 has one or more flap assemblies 7 that regulate the air outlet into the vehicle cabin. These can vary depending on the equipment type and typically include one or more of the following outlets: passenger air vent, defroster outlet, foot outlet, and outlets for rear or seat air conditioning. The air conditioning unit can also be equipped as a single-zone or multi-zone air conditioning unit (not shown).

[0016] Directly downstream of the air inlet housing 1 is a diffuser housing 11, which tapers in cross-section downstream and into which a blower unit 5 is integrated. The blower unit 5, which is completely enclosed by the diffuser housing 11, is designed as a radial blower and comprises a fan wheel 3 with backward-curved blades and a fan motor 4. Between the fan wheel 3 and the inner wall of the diffuser housing 11 are guide vanes, which laterally deflect the air flowing radially from the radial blower to the inner wall of the diffuser housing 11 in an axial direction. Air guiding means (not shown) can be provided in front of the diffuser housing 11 such that the diffuser housing 11 is subjected to a circular flow.

[0017] The fan motor 4 is arranged centrally on the downstream side in the area of ​​the rotation axis 12 of the fan wheel 3. Thus, the fan motor 4 is surrounded by the conveyed air volume flow on all sides.

[0018] Downstream of the end of the tapered diffuser housing 11 is another housing section, which merges even further downstream into the air outlet housing 2. Arranged in this housing section, one behind the other in the direction of air flow, are an air filter 10, an evaporator (cooling device) 6 acting as a cooling device, and a heating heat exchanger (heating device) 8 acting as a heating device, which are known from the prior art. Via a flap arrangement 14, the air flow emerging from the evaporator 6 can be directed entirely or partially through the heating heat exchanger 8 in order to implement temperature control, as is known from the prior art. The flap arrangement 14 can consist of any suitable combination of several flaps and can include, for example, wing flaps and / or sliding flaps.

[0019] According to the invention, the blower unit 5, the evaporator 6 and the heating heat exchanger 8 are arranged parallel one behind the other. The projection (ie the extension, see Fig. 1) The rotational axis 12 of the fan wheel 3 intersects the air inlet surface 9 of the evaporator 6 essentially at right angles and centrally. The fan motor 4 is also arranged centrally, slightly downstream of the fan wheel 3, so that it is intersected by the rotational axis 12 of the fan wheel 3.

[0020] Such an arrangement allows the air conditioning unit 20 to be constructed very compactly. The distance between the fan unit 5 and the air filter 10 arranged in front of the evaporator 6 is in the illustrated embodiment in a range between 3 and 8 cm. REFERENCE SYMBOL 1 air inlet housing (air inlet part) 2 air outlet housing (air outlet part) 3 Fan wheel 4 Fan motor 5 Blower unit 6 Cooling device (evaporator) 7 Flap arrangement air outlet 8 Heating device (heat exchanger) 9 Air inlet surface of the evaporator 10 air filters 11 Diffuser housing 12 Fan rotation axis 13 Flap arrangement air inlet 14 Flap arrangement for temperature control 20 air conditioner

Claims

[1] Air conditioning device (20), in particular for a motor vehicle air conditioning system, comprising - an air-conducting housing (1, 2, 11) with at least one air inlet part (1), at least one air outlet part (2) and a diffuser housing (11) arranged therebetween, - a blower unit (5) arranged in the air-conducting housing (1, 2, 11) with a fan wheel (3) and a fan motor (4) and - a cooling device (6) with an air inlet surface (9) facing the blower unit (5), and a heating device (8) arranged downstream therefrom, both of which are arranged downstream of the blower unit (5) in the air-conducting housing (1, 2, 11), characterized bythat an air filter (10) is arranged between the blower unit (5) and the cooling device (6) and the blower unit (5) is aligned relative to the cooling device (6) such that the extension of the rotational axis (12) of the fan wheel (3) intersects the air inlet surface (9) of the cooling device (6). [2] Air conditioning unit (20) according to claim 1, characterized by that the projection of the rotation axis (12) intersects the air inlet surface (9) of the cooling device (6) centrally. [3] Air conditioning unit (20) according to one of claims 1 or 2, characterized by that the blower unit (5) is a radial blower and the fan wheel (3) has backward curved blades. [4] Air conditioning unit (20) according to one of claims 1 to 3, characterized by that the blower unit (5) is integrated into the diffuser housing (11), wherein the diffuser housing (11) preferably tapers in cross-section downstream and completely encloses the blower unit (5). [5] Air conditioning unit (20) according to one of the preceding claims, characterized by that the distance between the blower unit (5) and the air filter (10) arranged in front of it is less than 10 cm, preferably less than 5 cm. [6] Air conditioning device (20) according to one of the preceding claims, characterized by that air guiding means are provided in front of the diffuser housing (11) so that the diffuser housing (11) is subjected to a circular flow. [7] Air conditioning device (20) according to one of the preceding claims, characterized by that the fan motor (4) is arranged downstream of the fan wheel (3) and the cooling air is extracted from the air volume flow conveyed by the fan wheel (3) at the downstream end of the diffuser housing (11). [8] Air conditioning device (20) according to one of the preceding claims, characterized by that the blower unit (5), the cooling device (6) and the heating device (8) are arranged parallel one behind the other.

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