Patent Application
20230258410
This application claims priority from German Patent Application No. DE 102022103720.7, filed on Feb. 17, 2022, the entirety of which is hereby incorporated by reference in its entirety.
The invention relates to a heat exchanger, in particular for the refrigerant circuit of a motor vehicle, as well as a method for its manufacture and the use of the heat exchanger.
Patent specification DE 102004036951A1 describes a heat exchanger consisting of interconnected plates. Cavities are formed between the plates. Two media flow alternately through these cavities. The plates are profiled in such a way that contact points occur between the respective plates. In the area of which the plates are fixed to one another. The profiles of the plates and their contact points are designed in such a way that the flow of the first and second media forming between the plates from the respective inflow line to the respective outflow line does not follow a linear path. The plates have a repeating wave profile. The wave profile extends substantially transversely to the main flow direction and, in particular, is corrugated in a zigzag pattern around the extension direction. The flow path between the plates, as explained in patent specification DE 102004036951A1, disadvantageously has a component in the direction of the vertical axis. This component causes a disadvantageous pressure loss.
In contrast, the device according to the invention with the features of the independent patent claims has the advantage that a lower pressure loss occurs when the two media flow through the heat exchanger. This pressure loss does not have to be compensated by a larger number of plates. This is the measure to increase the flow cross-section. Advantageously, this results in the present invention using less material for the manufacture of the heat exchanger and thus reducing the manufacturing costs. Another advantage is that the performance of the heat exchanger can be better adapted to the underlying task.
The starting point of the invention is a heat exchanger consisting of a stack of plates stacked on top of each other. Said heat exchanger is made of a metallic material. The heat exchanger is formed of interconnected, preferably rectangular plates. This creates channels between the plates. Two heat-exchanging media flow alternately through the channels formed in this way via at least one inflow opening and at least one outflow opening. The two media flow from the respective inflow opening to the outflow opening of the plate. The plates have profiles. Contact points are created between the plates, where the plates are connected to one another. The resulting flow paths of the two media run from the respective inflow opening to the respective outflow opening. The flow has a main flow direction. The profiles of the plates as well as their contact points are shown in such a way that the profiles run essentially along the main flow direction of the flow that forms between the plates. The profiles are generated from a curve and thus run in a curved manner. A plane curve which changes only in one direction in space is selected as said curve. The selected curve preferably runs in waves along its extension direction.
The profiles in the plates increase the area available for internal heat transfer. The flow is also deflected several times by the profiles. This distributes the fluid more evenly across the entire width of the plate. It is also possible that a turbulent flow develops. The increase in surface area as well as the type of flow improves the heat transfer between the two media. A forming flow path runs along the profiles. According to the state of the art, the flow is deflected in the plane of the plate and also beyond the plane of the plate. In the present invention, the flow is advantageously deflected in the plane of the plate only. This has the advantage that the resulting pressure loss is reduced. As well as that the performance of the heat exchanger can advantageously be adjusted according to the task.
According to the invention, the plates have profiles. The plates have a longitudinal direction, a transverse direction, and a vertical direction. The longitudinal direction coincides with the longer side of the rectangular plate. The extension direction of the profiles is along the longitudinal direction of the plate. The profiles run in waves. In this case, the main flow direction and the extension direction of the profiles coincide. The starting plate and the end plate are designed differently.
The profiles of the plates are formed in the following way. They consist of straight sections and tip angles. A tip angle is arranged between each of the straight sections. Two straight sections and the respective tip angles make up a wavelength of the profile. The number of straight sections and point angles is determined by a given division. The profile reoccurs regularly according to said division. Thus, the profiles are described by the division, the amplitude, the wavelength and the tip angle. The profile have a radius at the tip for better manufacturability.
The profile of the plate has at least one division. The number of divisions depends on the length of the plate. It is advantageous to choose a smaller number of divisions the longer the plate.
The plates according to the invention have different types of arrangements of the profiles. Contact points are formed between the profiles. The plates are connected at the contact points of the profiles. Due to the different arrangements of the profiles and their contact points, the channels for the flow paths are formed in an advantageously simple manner. In a first type of plate, the profile is symmetrical to the transverse axis and longitudinal axis of the plate. This results in a first type of plate.
A second type of plate advantageously results in the following manner. The profile of the second plate is shifted in the direction of the transverse axis by no more than half the wavelength compared to the profile of the first type of plate. Another type of plate advantageously results in the following manner. The profile of this third type of plate is twisted by 180° about the vertical axis of the plate compared to the profile first type of plate. In addition, the profile is shifted by any desired value in the direction of the transverse axis.
The heat exchanger according to the invention is formed from a stack of plates according to the invention. The first type of plate is used. Then the second type of plate or, alternatively, the third type of plate is placed over it. The stack of plates is formed by alternately arranging more and more plates of the two types used, one above the other. Until the heat exchanger with the desired properties is obtained. The stack is terminated by a start plate and an end plate.
The profile of the plate according to the invention is advantageously described by the division, amplitude, wavelength and tip angles. The amplitude of the profile of the plate is preferably between 1.0 to 3.5 mm. The wavelength of the profile of the plate is preferably between 2.0 and 9.0 mm. The tip angle between the straight sections of the profile is preferably between 90° and 180°.
The plate according to the invention has inflow openings and outflow openings for the two media. The inflow opening for the inflow and the outflow opening (ÄÖ1) for the outflow of the first medium is up to a factor of 10 larger than the inflow openings and outflow openings of the second medium. This is particularly advantageous if the first medium is gaseous. The second medium is liquid.
In the plate according to the invention, there is one main direction of flow of the medium. This flow direction runs from the respective inflow opening to the outflow opening in the plate. The inflow openings as well as the outflow openings can be arranged in various ways in the plate. If a type of flow of the medium, such as a U-flow of the medium is desired. To change the flow of the medium, an additional profile is placed between the inflow opening and outflow opening. This profile can be straight. Additional contact points between the plates are added. The plates are connected at these contact points.
According to the invention, the plates are further made of a metallic material. In particular, the plates are made of aluminum. According to the invention, the plates should preferably be joined by a material bond at the contact points. In particular, it is envisaged that the plates are joined by brazing.
The method of manufacturing a heat exchanger according to the invention involves embossing the plates, stacking the plates one on top of the other, and joining the plates to one another in a material-to-material bond. Preferably, brazing should be used as the material-bonding process. The first type of plate together is always alternately superimposed with another type of plate.
The heat exchanger according to the invention is used in a refrigerant circuit for a motor vehicle. For example, in a refrigerant circuit consisting of a compressor, an expansion mechanism, at least one heat exchanger according to the invention, and the connecting pipes.
An internal heat exchanger transfers heat within the refrigerant circuit. In an additional application, the heat exchanger according to the invention is used as an internal heat exchanger for a motor vehicle. An example is the use as an oil cooler in a motor vehicle.
The invention is illustrated in the drawing and explained in more detail in the following description.
Wherein:
To simplify the description, longitudinal axis LA. denotes the longer side of a plate The shorter side is called the transverse axis QA and the resulting third axis is called the vertical axis HA.
Various aspects of the application are represented by the following numbered paragraphs:
Numbered Paragraph 1:
A heat exchanger (100), in particular for the refrigerant circuit of a motor vehicle, wherein the heat exchanger (100) is formed from plates (PL) which are connected to one another, wherein channels (K) are formed between the plates (PL), two heat exchanging media (M1, M2) flow alternately through the channels (K) formed in this way via at least one inflow opening (ZÖ) and at least one outflow opening (AÖ), wherein the plates (PL) have profiles (PR), such that contact points are formed between the plates (PL), at which contact points the plates (PL) are connected to one another, such that flow paths (SP) of the two media (M1, M2) are formed from the respective inflow opening (ZL) to the respective outflow opening (AÖ), wherein the flow has a main flow direction (HS), characterized in that the profiles (PR) of the plates (PL) and their contact points (KS) are shown in such a way that the profiles (PR) run essentially along the main flow direction (HF) of the flow which is formed between the plates (PL).
Numbered Paragraph 2: The heat exchanger (100) according to Numbered Paragraph 1, characterized in that the plates (PL) alternately and respectively have a profile (PR) differing from the adjacent plates (PL), wherein the profiles (PR) run in a curved manner, in particular having waves along the extension direction.
Numbered Paragraph 3: The heat exchanger (100) according to Numbered Paragraph 1 and 2, characterized in that the profile (PR) of the plates (PL) between straight sections has a tip angle (α) which reoccurs at a predetermined division (T) such that the profile (PR) is described by the division (T), an amplitude (A), a wavelength (WL), the tip angle (α), wherein the profile (PR) has a radius (RA) at the tip.
Numbered Paragraph 4: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the profile (PR) of the plates (PL) has at least one division (T), wherein the number of divisions (T) depends on the length of the plate (PL), such that the longer the plate (PL), the smaller the number of divisions (T).
Numbered Paragraph 5: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the profile (PR) forms a first plate (301) and in that the profile (PR) is respectively arranged symmetrically with respect to the transverse axis (QA) and longitudinal axis (LA) of the plate (PL, 200).
Numbered Paragraph 6: The heat exchanger according to the preceding Numbered Paragraphs, characterized in that the profile (RR) of the second plate (301) is shifted in the direction of the transverse axis (QA) by at most half the wavelength (WL) compared to the first plate (200).
Numbered Paragraph 7: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the profile (PR) of a third plate (302) is rotated by 180° about the vertical axis (HA) of the plate (302) compared to the first plate (200), wherein the profile (PR) is also shifted by any desired value in the direction of the transverse axis (QA).
Numbered Paragraph 8: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the heat exchanger (100) is formed of a stack of plates (600), wherein both types of plates (PL) are arranged always alternately one above another.
Numbered Paragraph 9: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the amplitude (A) of the profile (PR) of the plate (PL) is preferably between 1.0 to 3.5 mm.
Numbered Paragraph 10: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the wavelength (WL) of the profile (PR) of the plate (PR) is preferably between 2.0 and 9.0 mm.
Numbered Paragraph 11: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the tip angle (α) between the straight sections of the profile (PR) is preferably between 90° and 180°.
Numbered Paragraph 12: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the inflow opening (ZÖ1) for the inflow, the outflow opening (ÄÖ1) for the outflow of the first medium (M1), in particular for a gaseous medium (M1), are by up to a factor of 10 larger than the inflow opening (ZÖ2) for the inflow and the outflow opening (ÄÖ2) for the outflow of the second medium (M2),
Numbered Paragraph 13: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the plates (PL) between the inflow openings (ZÖ1, ZÖ2) and outflow openings (ÄÖ1, ÄÖ2), respectively, have an additional profile (PRZ), in particular a straight profile, resulting in additional contact points (KS) between the plates (PL) at which the plates (PL) are connected.
Numbered Paragraph 14: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the plates (PL) are made of a metallic material, in particular aluminum.
Numbered Paragraph 15: The heat exchanger (100) according to the preceding Numbered Paragraphs, characterized in that the plates (PL) are connected at the contact points (KS), preferably by material bonding, in particular by brazing.
Numbered Paragraph 16: A method for producing a heat exchanger (100), in particular according to the preceding Numbered Paragraphs, characterized in that the method comprises, in particular, embossing the plates (PL), stacking (600) the plates (PL) one on top of the other, and joining the plates (PL) to one another with a material bond, in particular brazing.
Numbered Paragraph 17: The method according to Numbered Paragraph 16, characterized in that the first type of plate (200) is always arranged alternately with the other type of plate (301) or plate (302) on top of each other.
Numbered Paragraph 18: A refrigerant circuit, preferably for a motor vehicle, having a condenser, an evaporator, an expansion mechanism, at least one heat exchanger (100), the connecting pipes, characterized in that the heat exchanger (100) is designed according to at least one of the preceding Numbered Paragraphs 1-15.
Numbered Paragraph 19: A heat exchanger, in particular an internal heat exchanger for a motor vehicle, preferably an oil cooler, characterized in that the heat exchanger (100) is designed according to at least one of the preceding Numbered Paragraphs 1-15.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102022103720.7 | Feb 2022 | DE | national |
