WO2015039894A1

WO2015039894A1 - Heat exchanger

Info

Publication number: WO2015039894A1
Application number: PCT/EP2014/068965
Authority: WO
Inventors: Christioph STRELLER
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2013-09-17
Filing date: 2014-09-05
Publication date: 2015-03-26
Also published as: CN105518406B; CN105518406A; EP3047222B1; EP3047222A1; DE102013218587A1

Abstract

The invention relates to a heat exchanger, in particular for an internal combustion engine of a motor vehicle. The heat exchanger has at least two cooling elements (9) through which a heat-conducting fluid (14) can flow and at least one flow channel (10) which is arranged between the cooling elements (9) and through which a cooling air (11) can flow. The aim of the invention is to improve the cooling capacity of the heat exchanger. According to the invention, this is achieved in that the flow channel (10) extends between the two cooling elements (9) such that a flow direction (12) of the cooling air (11) in the flow channel (10) runs parallel to a flow direction (13) of the heat-conducting fluid (14) in the two cooling elements (9).

Description

description

heat exchangers

The invention relates to a heat exchanger, in particular for an internal combustion engine of a motor vehicle, with at least two cooling elements through which a heat-conducting fluid can flow and with at least one flow channel arranged between the cooling elements and through which cooling air can flow.

Motor vehicles are usually equipped with at least one heat exchanger, which serves to dissipate resulting in the operation of an internal combustion engine waste heat to the environment. The heat exchanger, also referred to as a water cooler, is usually arranged in a front region of the motor vehicle and is thermally coupled to the internal combustion engine by a fluid containing a coolant additive.

To dissipate the waste heat of the internal combustion engine to the environment of the heat exchanger is exposed to an air flow. This is for example while driving through the

Driving movement of the motor vehicle generated or can be generated or amplified at slow speed or at a standstill of the motor vehicle by a blower.

Common heat exchangers, as well as the one disclosed in DE 10 2010 027 053 A1, have a plurality of cooling elements which can flow through a heat-conducting fluid and are designed as tubes, which extend parallel to one another over the plane of an inflow surface of the heat exchanger. Between the cooling elements can be traversed by the fluid fins are provided which are thermally coupled to the cooling elements and at the same time provide the largest possible area for the removal of waste heat from the fluid to the air flow or the ambient air.

In this case, the heat exchanger has a plurality of cooling elements extending parallel to one another and designed as tubes. In an installation situation of the heat exchanger in the motor vehicle, the cooling elements extend in a plane formed by the vehicle transverse direction and motor vehicle vertical direction, parallel to the plane

Motor vehicle transverse direction. The guided through the cooling elements heat-conducting fluid thus flows so substantially in the vehicle transverse direction, while the guided through the fins in the flow channel between the cooling elements, heat-absorbing cooling air in Vehicle longitudinal direction flows. The flow direction of the heat-conducting fluid and the flow direction of the cooling air are thus aligned orthogonal to each other.

To provide sufficient for the operation of an internal combustion engine cooling power a comparatively large design is provided for known heat exchangers. In this case, the heat exchanger essentially uses the entire surface which is available in the front region of the motor vehicle and extends in the vehicle transverse direction and vehicle vertical direction as the inflow surface. Due to structural and geometric requirements of the

Motor vehicle body is the available area in the front area and thus also limited to the inflow of the heat exchanger. This also results in a limitation of the cooling capacity of the heat exchanger. If the inflow surface of the heat exchanger must be reduced due to changes in geometric or structural specifications or in

Motor vehicle a more powerful and thus more waste heat generating

If the internal combustion engine is to be installed, the cooling capacity of the heat exchanger which is to be generated with the available inflow area may no longer suffice to ensure sufficient cooling and trouble-free operation of the heat exchanger

Ensuring internal combustion engine.

Against this background, the invention has for its object to perform a heat exchanger of the type mentioned in such a way that it has a better cooling performance for the same inflow.

This object is achieved with a heat exchanger according to the features of

The subclaims relate to particularly expedient developments of the invention.

According to the invention, therefore, a heat exchanger is provided, in which the

Flow channel extends between the two cooling elements such that a

Flow direction of the cooling air in the flow channel parallel to a flow direction of the heat-conducting fluid in the two cooling elements extends. Because of that

Flow directions of the heat-emitting fluid and the flow direction of the heat-absorbing fluid are arranged parallel to each other, the distance, on which the fluid can transfer the absorbed heat to the cooling air, extended. Compared to the aforementioned prior art, in which the flow directions of the fluid and the cooling air are arranged orthogonal to each other, so more heat from the Fluid are discharged to the cooling air. As a result, the heat exchanger with the same inflow surface better cooling performance and better efficiency, so that the heat exchanger at the same cooling capacity must have a smaller inflow than a previously used heat exchanger.

In this case, the flow directions of the fluid and the cooling air can run in the same direction. A particularly advantageous development of the present invention provides, however, that the flow direction of the cooling air in the flow channel in the opposite direction to the flow direction of the heat-conducting fluid in the two cooling elements extends.

Characterized in that the heat-carrying fluid and the heat-absorbing cooling air in

In the opposite direction, a temperature gradient always exists between the fluid and the cooling air, so that a very large part of the heat load of the fluid can be transferred to the cooling air.

A further improvement of the cooling capacity of the heat exchanger is also achieved in that the cooling elements each at least two juxtaposed and in

Flow direction of the heat-conducting fluid have extending fluid channels.

This increases the heat transfer area between the fluid and the cooling air and allows more heat to be dissipated from the fluid to the cooling air.

It proves to be particularly expedient that the fluid channels are formed such that the flow direction of the heat-conducting fluid in at least a first

Fluid channel in the flow direction of the cooling air and in a second fluid channel in the opposite direction to the flow direction of the cooling air extends. In such a case, the end portions of the fluid channels of the cooling elements are at least partially by deflection

fluidically interconnected. By this deflection, the fluid to be cooled within the cooling elements can be deflected one or more times, so that almost the entire heat load of the fluid can be transferred to the cooling air.

Furthermore, it proves to be advantageous for the heat transfer between the fluid and the cooling air that a surface of the cooling elements facing the fluid flowing through has indentations and / or that flow-conducting devices, in particular baffles, are arranged in the cooling elements. As a result, the surface of the cooling elements are increased and improves the heat transfer. In addition, through the indentations or by arranged in the cooling elements baffles, inlays or turbulators the Flow of the fluid in the cooling elements can be influenced such that the total flow-through distance is extended in the cooling elements.

In addition, it is provided that the cooling elements are formed as horizontally or vertically arranged plates and arranged parallel to each other. In a vertical arrangement of the plates, a good uniform distribution of the heat-conducting fluid is possible on the individual plates. This results in addition in a lower pressure loss of the heat-conducting or heat-emitting fluid.

A further feature of the invention is that the plates are arranged inclined to a horizontal or vertical plane, that include a flow direction of the cooling air before entering the flow channel and the flow direction of the cooling air in the flow channel at an obtuse angle. Due to the inclined arrangement of the plates, the heat transfer path between the fluid and the cooling air is extended for the same available space. Depending on the size of the obtuse angle, the aerodynamic properties of the motor vehicle and also the

Cooling capacity of the heat exchanger. An inclination of the plates, in which the direction of flow of the air flow generated by the driving movement of the motor vehicle before entering the flow channel and the flow direction of the cooling air in the flow channel form an angle between 125 ° and 145 °, provides optimal results in terms of

aerodynamic properties and the cooling capacity of the heat exchanger.

It has proven particularly expedient that the two plates enclosing the flow channel between them are fluidically connected to one another and have a common inlet and a common outlet for the heat-conducting fluid, wherein the inlet is on a side facing the cooling-air outlet surface of the flow channel and the outlet is arranged on one of the cooling air inlet surface of the flow channel facing side of the plates and / or that the inlet is arranged with respect to a horizontal plane in an upper region and the drain in a lower edge region of the plates.

A particularly large area for dissipating waste heat to the ambient air is also created by the fact that in the flow channel fins are arranged, which are thermally coupled to the cooling elements. In a further independent aspect, the invention also relates to a motor vehicle with an internal combustion engine and with a heat exchanger for dissipating the heat generated during operation of the internal combustion engine waste heat to the environment. It is the

Heat exchanger formed as described above.

The invention allows numerous embodiments. To further clarify its basic principle, one of them is shown in the drawing and will be described below. This shows in

1 shows a motor vehicle with an arranged in a front region of the internal combustion engine and with a heat exchanger according to the invention in a plan view.

Fig. 2 is a greatly simplified schematic diagram of the front portion of the motor vehicle

Side view;

Fig. 3 is a greatly simplified schematic diagram of the illustrated in Figures 1 and 2

heat exchanger;

4 shows a first embodiment of the heat exchanger in a perspective view;

Fig. 5 shows a second embodiment of the heat exchanger in a perspective

Presentation;

Fig. 6 shows a third embodiment with respect to a horizontal plane inclined

arranged cooling elements;

Fig. 7 is a perspective and sectional view of a plate of the heat exchanger.

FIG. 1 shows a motor vehicle 1 with one arranged in a front region 2

Internal combustion engine 3 and with a heat exchanger 4 in a plan view, while Figure 2 shows a simplified schematic diagram of the front portion 2 in a side view.

The internal combustion engine 3 and the heat exchanger 4 are arranged in an engine compartment 5 of the motor vehicle 1 such that the heat exchanger 4 is in the direction of travel 6 of the motor vehicle 1 in front of the internal combustion engine 3. To dissipate generated during operation of the internal combustion engine 3 waste heat to the environment is the Internal combustion engine 3 is thermally coupled via a fluid having a coolant fluid with the formed as a water cooler heat exchanger 4. The heat-conducting fluid is introduced during operation of the internal combustion engine 3 in the heat exchanger 4 and outputs the heat absorbed to a likewise introduced into the heat exchanger 4 cooling air. By the movement of the motor vehicle 1 in the direction of travel 6 is a

Air flow generated with one of the direction of travel 6 opposite flow direction 7 and introduced via an inflow surface 8 of the heat exchanger 4 in this.

3 shows a greatly simplified schematic diagram of the heat exchanger 4 according to the invention with two cooling elements 9 arranged in parallel and with a flow channel 10 extending between them. The air flow directed onto the inflow surface 8 of the heat exchanger 4 in the inflow direction 7 is introduced into the flow channel 10 and flows as cooling air 1 1 through the flow channel 10. In this case, the cooling air 1 1 a

Flow direction 12, which is parallel and in the opposite direction to a flow direction 13 of the flowing through the cooling elements 9 fluid 14. The cooling elements 9 can be arranged one above the other (FIGS. 3 and 4) or side by side (FIG. 5) with respect to a horizontal plane (xy-plane), the flow direction 13 of the fluid 14 being parallel to the flow direction 12 of the cooling air 11 in both cases ,

Figure 4 shows an embodiment of the heat exchanger 4 according to the invention in a perspective view. The heat exchanger 4 has a plurality of cooling elements 9 formed as plates 15, wherein the plates 15 are arranged horizontally and parallel to each other. Between each adjacent plates 15, a flow channel 10 extends, so that the heat exchanger 4 consists of a plurality of plates 15 and a plurality of flow channels 10. In the flow channels 10 10 cooling fins 16 are arranged to increase the surface of the flow channel, which are thermally coupled to the cooling elements 9 and the plates 15. The plates 15 extend parallel to a through the vehicle transverse direction (y-axis) and the vehicle longitudinal direction (x-axis) spanned plane and each have a plurality of juxtaposed and extending in the flow direction 13 of the fluid 14 fluid channels 17.

For the introduction and the discharge of the waste heat of the internal combustion engine 3 receiving fluid 14 in or out of the heat exchanger 4, this has an inlet 18 and a drain 19. The inlet 18 is on one of the cooling air outlet surface 20 of the

Heat exchanger 4 facing side and the drain 19 on one of the cooling air inlet surface 21 of the heat exchanger 4 facing side of the respective plate 15 is arranged. Through the inlet 18 is coming from the internal combustion engine 3 and heat leading Fluid 14 introduced into the top plate 15 relative to a horizontal plane (xy plane), then distributed within this plate 15 on the adjacent fluid channels

17 and flows through these in the flow direction 13. Since the individual horizontally arranged plates 15 are fluidically connected to each other, this is distributed through the inlet

18 introduced into the uppermost plate 15 fluid 14 evenly into the superposed plates 15 and flows through them in the flow direction 13. During the flow through the plates 15, the fluid 14, the heat absorbed to the flowing in the opposite direction cooling air 1 1 from. Subsequently, the fluid 14 is discharged via the outlet 19 in the bottom plate 15 from the heat exchanger 4 and returned to the internal combustion engine 3.

Figure 5 shows a modified embodiment, according to which the plates 15 of

Heat exchanger 4 are not horizontally but vertically arranged as in the embodiment shown in Figure 4. The plates 15, which are also arranged in parallel, thus extend in this embodiment, parallel to a plane defined by the direction of travel of the motor vehicle (z-axis) and the vehicle longitudinal direction (x-axis).

FIG. 6 shows a further embodiment according to which the plates 15 or the cooling elements 9 are arranged parallel to one another and inclined to a horizontal plane (xy plane). The inclination of the cooling elements 9 is designed such that a direction of flow 8 of the

Air flow before entering the flow channel 10 and the flow direction 12 of the cooling air 1 1 in the flow channel 10 include an obtuse angle 22. In this way, a heat transfer path 23 between the cooling elements 9 and the flow channel 10 or the fluid 14 and the cooling air 1 1 is extended compared to an arrangement of Figure 3 with the same available space and thereby improves the cooling capacity of the heat exchanger 4.

Figure 7 shows a perspective and sectional view of a plate 15 of the

Heat exchanger 4. In the plate 15, a flow-conducting device 24 is integrated. By designed as a guide plate flow-conducting device 24 which are in

Flow direction 13 of the heat-conducting fluid 14 extending, juxtaposed fluid channels 17 formed. Furthermore, a surface 25 of the cooling elements 9 or the plates 15 facing the throughflowing fluid 14 may have indentations 26. In addition, 17 may be provided within the plate 15 and in the individual fluid channels 17 further flow-conducting or turbulence-generating elements or geometries, such as sheets, turbulators or inlays. This will be a improved heat transfer between the heat-conducting fluid 14 and the cooling air 1 1 achieved in the flow channel 10.

As shown in FIG. 5, the plates 15 can have deflection devices 28, which connect adjacent fluid channels 17 to one another in terms of flow. As a result, the fluid 14 flowing in the opposite direction to the cooling air 1 1 is deflected by 180 ° (dashed line), so that the flow direction 13 of the fluid 14 then has the same flow direction as the cooling air 1 1 in the flow channel 10.

Motor vehicle

front area

Internal combustion engine

heat exchangers

Engine compartment direction of travel

Direction of flow (air flow)

inflow area

cooling element

Flow channel cooling air

Flow direction (cooling air)

Flow direction (fluid)

fluid

Plate cooling fins

fluid channel

Intake

procedure

Cooling air outlet surface Cooling air inlet surface

dull angle

Heat transfer distance

Facility

Surface impressions

element

deflecting

Claims

claims

1. heat exchanger (4), in particular for an internal combustion engine (3) of a

Motor vehicle (1), with at least two of a heat conducting fluid (14) through which cooling elements (9) and with at least one between the

Cooling elements (9) arranged and by cooling air (1 1) flow-through flow channel (10), characterized in that the flow channel (10) between the two cooling elements (9) extends such that a flow direction (12) of the cooling air (1 1) in the flow channel (10) parallel to a flow direction (13) of the heat-conducting fluid (14) in the two cooling elements (9).

2. Heat exchanger (4) according to claim 1, characterized in that the

Flow direction (12) of the cooling air (1 1) in the flow channel (10) in the opposite direction to the flow direction (13) of the heat-conducting fluid (14) in the at least two cooling elements (9).

3. Heat exchanger (4) according to claims 1 or 2, characterized in that the cooling elements (9) in each case at least two juxtaposed and in

Flow direction (13) of the heat-conducting fluid (14) extending fluid channels (17).

4. Heat exchanger (4) according to at least one of the preceding claims, characterized in that the fluid channels (17) are formed such that the

Flow direction (13) of the heat-conducting fluid (14) in at least a first fluid channel (17) in the direction of flow (12) of the cooling air (1 1) and in a second fluid channel (17) in the opposite direction to the flow direction (12) of the cooling air (1 1) runs.

5. Heat exchanger (4) according to at least one of the preceding claims, characterized in that the end regions of the fluid channels (17) of the cooling elements (9) are at least partially fluidically connected by a deflection device (28).

6. Heat exchanger (4) according to at least one of the preceding claims, characterized in that a fluid flowing through the heat (14) facing surface (25) of the cooling elements (9) indentations (26) and / or that in the cooling elements (9) flow-conducting means (24), in particular baffles and / or elements (27) are arranged.

7. Heat exchanger (4) according to at least one of the preceding claims, characterized

characterized in that the cooling elements (9) are formed as horizontally or vertically arranged plates (15) and arranged parallel to each other.

8. Heat exchanger (4) according to at least one of the preceding claims, characterized

in that the plates (15) are arranged inclined to a horizontal (xy plane) or vertical plane (xz plane) such that a direction of flow (7) of an air flow before entering the flow channel (10) and the flow direction (FIG. 12) of the cooling air (1 1) in the flow channel (10) include an obtuse angle (22).

9. Heat exchanger (4) according to at least one of the preceding claims, characterized

characterized in that the plates (15) are fluidically connected to one another and have a common inlet (18) and a common outlet (19) for the heat-carrying fluid (14), wherein the inlet (18) on one of the cooling air outlet surface (20) of the Heat exchanger (4) facing side and the drain on one of

Cooling air inlet surface (21) of the heat exchanger facing side of the plates (15) is arranged and / or that the inlet (18) relative to a horizontal plane (xy plane) in an upper region and the outlet (19) in a lower region of the plates (15) is arranged.

10. Motor vehicle (1) with an internal combustion engine (3) and with a heat exchanger (4) for removing the heat generated during operation of the internal combustion engine (3) to the environment according to at least one of the preceding claims.