CN220250300U

CN220250300U - Electric heating device

Info

Publication number: CN220250300U
Application number: CN202190000535.2U
Authority: CN
Inventors: A.费夫雷; B.纳贾; O.E.阿尔科瑟
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2020-06-24
Filing date: 2021-06-16
Publication date: 2023-12-26
Anticipated expiration: 2031-06-16
Also published as: WO2021259716A1; JP2023531088A

Abstract

An electrical heating device (1) is disclosed, the electrical heating device (1) comprising a housing defining a heating chamber (3), the heating chamber comprising a tubular cavity (32) within which a heat transfer fluid is arranged to circulate between a heat transfer fluid inlet (3 a) and a heat transfer fluid outlet (3 b), wherein, within the tubular cavity (32), an electrical heating element (31) extends, the electrical heating element comprising a first inner spiral resistance (31 a) and a second outer spiral resistance (31 b), the outer resistance (31 b) being the second resistance surrounding the first inner resistance (31 a), the first resistance (31 a) and the second resistance (31 b) having opposite winding directions with respect to each other, the heat transfer fluid inlet (3 a) being arranged tangential to the tubular cavity (32) so as to generate a spiral heat transfer fluid flow within the tubular cavity (32) between the heat transfer fluid inlet (3 a) and the heat transfer fluid outlet (3 b), the spiral winding direction of the heat transfer fluid flow being opposite to the winding direction of the outer resistance (31 b) being the second resistance.

Description

Electric heating device

Technical Field

The field of the utility model is electrical devices for heating and circulating heat transfer fluids, in particular for heating, ventilation and/or air conditioning equipment of the interior of motor vehicles. More particularly, the utility model relates to an electric heating device for such a device in electric or hybrid motor vehicles equipped with a high-voltage electric power supply network.

Background

Air for heat treatment of the interior of a motor vehicle having a heat engine is heated via a radiator by heat exchange between an air stream and a heat transfer fluid. In the case of hybrid or electric vehicles, electric heating devices are known which form a source of thermal energy and in which an electric current, typically of high voltage, is circulated in order to raise the temperature of an electric heating element built into the heating device. The heat transfer fluid to be heated thus passes through the electric heating device and is in contact with the electric heating element; there is then a thermal energy exchange between the electric heating element and the heat transfer fluid. The heat transfer fluid then enters a radiator disposed within the heating, ventilation and/or air conditioning apparatus to heat the air flow to the interior.

The electrical heating element is typically composed of an electrical heating device, such as one or more heating resistors. The quality of the heat exchange between the heat transfer fluid and the electric heating element may still change during the circulation of the heat transfer fluid within the electric heating device, in particular along the electric heating element. Thus, this may lead to hot spots forming at the electrical heating element, which may potentially reduce its effectiveness over time. This may also lead to areas where the heat transfer fluid has a higher or lower temperature, which may lead to a temperature change of the heat transfer fluid at the outlet of the electric heating device, which will have an influence on e.g. the radiator and thus the comfort of the occupants.

Disclosure of Invention

It is therefore an object of the present utility model to at least partly overcome the disadvantages of the prior art and to propose an improved electric heating device.

The utility model therefore relates to an electric heating device for heating a heat transfer fluid of a motor vehicle, said electric heating device having a housing defining a heating chamber comprising a tubular cavity in which the heat transfer fluid is intended to circulate between an inlet and an outlet for the heat transfer fluid,

wherein, within the tubular cavity, an electrical heating element extends, comprising an inner spiral resistor as a first resistor and an outer spiral resistor as a second resistor,

the external resistor as the second resistor surrounds the internal resistor as the first resistor,

the first and second resistors have opposite clockwise or counterclockwise winding directions from each other in a direction from the inlet to the outlet of the heat transfer fluid,

the inlet of the heat transfer fluid is arranged tangentially to the tubular chamber so as to create a clockwise or anticlockwise spiral flow of heat transfer fluid within the tubular chamber between the inlet and outlet of the heat transfer fluid, the spiral flow of heat transfer fluid being wound in a direction opposite to that of the external resistor acting as a second resistor.

According to one aspect of the utility model, the inner spiral resistor as a first resistor and the outer spiral resistor as a second resistor form turns around the rotation axis of the tubular cavity.

According to another aspect of the utility model, the first and second resistors have a constant winding diameter along the axis of rotation of the tubular cavity.

According to another aspect of the utility model, the tubular cavity has a lateral tubular wall extending between first and second end walls, the first and second end walls being disposed at each end of the lateral tubular wall, respectively, the inlet for the heat transfer fluid being disposed on said lateral tubular wall.

According to another aspect of the utility model, the inlet for the heat transfer fluid is arranged substantially perpendicular to a plane passing through the rotation axis of the tubular cavity.

According to another aspect of the utility model, the outlet for the heat transfer fluid is provided in one of the first and second end walls of the tubular chamber substantially parallel to the axis of rotation of said tubular chamber.

According to another aspect of the utility model, the outlet for the heat transfer fluid is provided on an edge of the first or second end wall.

According to another aspect of the utility model, the tubular cavity is frustoconical.

According to another aspect of the utility model, the inlet for the heat transfer fluid is provided at a first end of the tubular chamber and the outlet for the heat transfer fluid is provided at a second end of the tubular chamber opposite the first end.

According to another aspect of the utility model, the diameter of the tubular cavity at the first end is greater than the diameter of said tubular cavity at the second end.

According to another aspect of the utility model, the turns of the first and/or second spiral resistor have a constant pitch.

According to another aspect of the utility model, the pitch of the turns of the first spiral resistor and the pitch of the turns of the second spiral resistor are the same.

According to another aspect of the utility model, the first and second resistors are each formed by a tubular string, the diameter of which is constant over its entire length.

Drawings

Further characteristics and advantages of the utility model will become more apparent from reading the following description, provided by way of non-limiting illustration, with reference to the accompanying drawings, in which:

FIG. 1a is a schematic perspective view of an electrical heating device;

FIG. 1b is a schematic exploded perspective view of the electric heating device of FIG. 1 a;

FIG. 2 is a schematic view of a longitudinal cross-section of the electric heating device of FIG. 1 a;

FIG. 3 is a schematic view of a transverse cross-section of the electric heating device of FIG. 1 a;

FIG. 4 is a schematic perspective view of an electrical heating element;

like elements in different drawings have the same reference numerals.

Detailed Description

The following embodiments are examples. While the description is directed to one or more embodiments, this does not necessarily mean that each is directed to the same embodiment, or that the features are applicable to only a single embodiment. Various features of the different embodiments may also be combined and/or interchanged to provide other embodiments.

In this specification, certain elements or parameters may be indexed, such as a first element or a second element, and a first parameter and a second parameter, or a first criterion and a second criterion, etc. In this case, a simple index is of interest to distinguish and name similar but not identical elements or parameters or criteria. Such references do not imply a preference for one element, parameter or criterion over another, and such designations may be readily interchanged without departing from the scope of the specification. Such indexing also does not imply any chronological order, for example, when evaluating any given criteria.

Fig. 1a and 1b show a schematic perspective view of an electric heating device 1 in an assembled view and an exploded view, respectively.

The electric heating device 1 has a housing defining at least one heating chamber 3, a heat transfer fluid being intended to circulate inside said heating chamber 3. More specifically, the heating chamber 3 has a tubular cavity 32, within which tubular cavity 32 a heat transfer fluid is used to enter and exit the heating chamber 3 between an inlet 3a (visible in fig. 3) for the heat transfer fluid and an outlet 3b (visible in fig. 2) for the heat transfer fluid, both inlet 3a and outlet 3b opening into said tubular cavity 32. The tubular cavity 32 may in particular have a lateral tubular wall 22a extending around the rotation axis X. At each end of the lateral tubular wall 22a first end wall 22b and a second end wall 22c are provided, respectively.

Within the tubular cavity 32 there extends at least one electric heating element 31 for heating a heat transfer fluid. The electric heating element 31 encloses, in particular, the heating chamber 3 and, more particularly, the tubular cavity 32, so that the heat transfer fluid can only circulate between the inlet 3a and the outlet 3b of the heat transfer fluid. The electric heating element 31 may thus have a second end wall 22c.

The electric heating device 1 may also have an extension 4 of the heating chamber 3 allowing access to the electrical connectors of the electric heating element 31. The extension 4 may be closed by a cover 41. The heat transfer fluid does not circulate in the extension 4.

The electric heating device 1 further has a recess 5, and an electronic management printed circuit board 51 is provided in the recess 5. The recess 5 may in particular have a cap 52 closing it. The recess 5 also has an electrical connector (not shown) for allowing the supply of electrical power to the printed circuit board 51, typically with low voltage power (e.g. from 12 to 48V), and to the electrical heating element 31, typically with high voltage current (which may exceed 500V for example for an electric vehicle).

The inlet 3a for the heat transfer fluid may in particular be arranged at a first end of the tubular chamber 32 and the outlet 3b for the heat transfer fluid may be arranged at a second end of the tubular chamber 32 opposite to the first end. This therefore allows the heat transfer fluid to circulate throughout the entire length of the electrical heating element 31.

As shown in the cross-section in fig. 2, in the installed state the tubular cavity 32 may in particular be inclined with respect to the horizontal plane. This inclination of the tubular cavity 32 allows, inter alia, a better evacuation of potential air bubbles which will thus accumulate in the top part.

Thus, in the installed state, the second end of the tubular cavity 32 may be disposed at a higher elevation than the first end of the tubular cavity 32. Thus, the air bubbles can be discharged through the outlet 3b of the heat transfer fluid. In order to make it easier to expel the air bubbles, an outlet 3b for the heat transfer fluid may be provided in the top part of the tubular cavity 32.

The outlet 3b for the heat transfer fluid may in particular be provided on one of the first end wall 22b and the second end wall 22c of the tubular chamber 32, substantially parallel to the rotation axis X of said tubular chamber 32. In the example shown in fig. 2, the outlet 3b for the heat transfer fluid is provided in the first end wall 22 b. The inlet 3a for the heat transfer fluid will then be provided at the opposite end of the tubular chamber 32, i.e. close to the second end wall 22c.

Still referring to fig. 2, the tubular cavity 32 may be frustoconical. This means that one of its ends has a larger cross-sectional diameter than the opposite end. More specifically, the diameter of the tubular cavity 32 is larger at its first end, at which the inlet 3a for the heat transfer fluid is provided, than at its second end, at which the outlet 3b for the heat transfer fluid is provided, than at the tubular cavity 32.

As shown in fig. 3, the inlet 3a for the heat transfer fluid is arranged tangentially to the tubular chamber 32, so that a clockwise or anticlockwise helical flow of heat transfer fluid is created within the tubular chamber 32 between the inlet 3a and the outlet 3b for the heat transfer fluid. More specifically, the inlet 3a may be provided on the lateral tubular wall 22a of the tubular cavity 32. The inlet 3a for the heat transfer fluid may in particular be arranged substantially perpendicular to a plane passing through the rotation axis X of the tubular cavity 32. This allows the flow of the heat transfer fluid to match the shape of the inner wall of the tubular cavity 32 and thus to have a spiral profile through the flow of the heat transfer fluid up to the outlet 3b.

As shown in more detail in fig. 4, the electric heating element 31 has in particular an inner spiral resistor 31a as a first resistor and an outer spiral resistor 31b as a second resistor. These first and second resistors 31a, 31b are in particular wound around the rotation axis X of the tubular cavity 32. More specifically, the external resistor 31b as the second resistor surrounds the internal resistor 31a as the first resistor. The first resistor 31a and the second resistor 31b also have clockwise or counterclockwise winding directions opposite to each other in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid. Thus, if the first resistor 31a has a clockwise winding direction in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid, the second resistor 31b will have a counter-clockwise winding direction in the same direction. Also, if the first resistor 31a has a counter-clockwise winding direction in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid, the second resistor 31b will have a clockwise winding direction in the same direction. In particular, the first resistor 31a and the second resistor may each be formed by a tubular string, the diameter of which is constant over its entire length.

More specifically, the first resistor 31a and the second resistor 31b may have a constant winding diameter along the rotation axis X of the tubular cavity 32. Thus, the electric heating element 31 has a cylindrical profile inside the tubular cavity 32.

As also shown in fig. 4 and 2, the turns of the first and second resistors 31a, 31b may have a constant pitch. Further, the pitch of the turns of the internal resistor 31a as the first resistor and the pitch of the turns of the internal resistor 31b as the second resistor may be the same. This significantly allows for easier manufacturing of the electrical heating element 31 and for uniform heating of the heat transfer fluid within the tubular cavity 32.

In fig. 4, the inlet 3a and the outlet 3b of the heat transfer fluid are indicated by grey arrows. The winding direction of the external resistor 31b as a second resistor is opposite to the winding direction of the spiral heat transfer fluid flow in the tubular chamber 32 in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid. Thus, if the second resistor 31b has a clockwise winding direction in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid, the spiral heat transfer fluid flow will have a counter-clockwise winding direction in the same direction. Also, if the second resistor 31b has a counter-clockwise winding direction in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid, the spiral heat transfer fluid flow will have a clockwise winding direction in the same direction. In combination with the tangential inlet 3a of the heat transfer fluid, this makes it possible to improve the performance of the electric heating device 1. More specifically, this makes it possible to increase the heat exchange coefficient between the heat transfer fluid and the electric heating element 31.

An electric heating device 1 has been simulated, which electric heating device 1 has a tangential inlet 3a for a heat transfer fluid and an electric heating element 31 with a power of 7kW, in which electric heating element 31a heat transfer fluid with a flow rate of 0.1726kg/s and an inlet temperature of 70 ℃ is circulated. In these simulations, the characteristics of the tubular cavity 32, such as volume, diameter, and length, are the same.

When the turns of the external resistor 31b as the second resistor are wound in the same direction (clockwise or counterclockwise) as the spiral heat transfer fluid flow in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid, the following result is obtained:

outlet temperature of heat transfer fluid: 81.4 DEG C

Pressure drop of the heat transfer fluid: 12mbar

Maximum temperature of the electric heating element 31: 190 DEG C

Proportion of heat transfer fluid in chamber 32 at a temperature above 100℃:9.5%

Proportion of heat transfer fluid in chamber 32 at a temperature above 130 c: 0.07%.

When the turns of the external resistor 31b as the second resistor are wound in the opposite direction (clockwise or counterclockwise) to the spiral heat transfer fluid flow in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid, the following result is obtained:

outlet temperature of heat transfer fluid: 81.5 DEG C

Pressure drop of the heat transfer fluid: 13mbar

Maximum temperature of the electric heating element 31: 178.8 DEG C

Proportion of heat transfer fluid in chamber 32 at a temperature above 100℃:1.4%

Proportion of heat transfer fluid in chamber 32 at a temperature above 130 c: 0.02%.

Thus, these simulations show that the highest temperature of the electric heating element 31 is lower when the turns of the external resistor 31b, which is the second resistor, are wound in the direction opposite to the spiral heat transfer fluid flow in the direction from the inlet 3a to the outlet 3b of the heat transfer fluid. This indicates a reduction in hot spots on the electrical heating element 31. The heat exchange between the electric heating element 31 and the heat transfer fluid is thus more uniform within the tubular cavity 32. This also results in a lower proportion of heat transfer fluid in chamber 32 at temperatures above 100 c. The temperature of the heat transfer fluid within the tubular chamber 32 is also more uniform. Furthermore, the pressure drop of the heat transfer fluid remains limited.

Claims

1. An electric heating device (1) for heating a heat transfer fluid of a motor vehicle, the electric heating device (1) having a housing defining a heating chamber (3), the heating chamber comprising a tubular cavity (32) inside which the heat transfer fluid is intended to circulate between an inlet (3 a) and an outlet (3 b) of the heat transfer fluid,

wherein inside the tubular cavity (32) an electric heating element (31) extends, said electric heating element comprising an inner spiral resistor (31 a) as a first resistor and an outer spiral resistor (31 b) as a second resistor,

characterized in that the outer spiral resistor (31 b) as a second resistor surrounds the inner spiral resistor (31 a) as a first resistor,

the first and the second resistor having mutually opposite clockwise or anticlockwise winding directions in the direction from the inlet (3 a) to the outlet (3 b) of the heat transfer fluid,

the inlet (3 a) of the heat transfer fluid is arranged tangentially to the tubular chamber (32) so as to create a clockwise or anticlockwise spiral flow of heat transfer fluid within the tubular chamber (32) between the inlet (3 a) and the outlet (3 b) of the heat transfer fluid, the spiral flow of heat transfer fluid having a winding direction opposite to that of the external spiral resistor (31 b) acting as a second resistor.

2. An electric heating device (1) according to claim 1, characterized in that said internal spiral resistor (31 a) as a first resistor and said external spiral resistor (31 b) as a second resistor form turns wound around the rotation axis (X) of the tubular cavity (32).

3. An electric heating device (1) according to claim 2, characterized in that the first and second resistors have a constant winding diameter along the rotation axis (X) of the tubular cavity (32).

4. An electric heating device according to any one of claims 1 to 3, wherein the tubular cavity (32) has a lateral tubular wall (22 a) extending between a first end wall (22 b) and a second end wall (22 c) provided at each end of the lateral tubular wall (22 a), respectively, the inlet (3 a) for the heat transfer fluid being provided on the lateral tubular wall (22 a).

5. An electric heating device (1) according to claim 4, characterized in that the inlet (3 a) for the heat transfer fluid is arranged substantially perpendicular to a plane passing through the rotation axis (X) of the tubular cavity (32).

6. An electric heating device according to claim 5, characterized in that the outlet (3 b) for the heat transfer fluid is provided on one of the first end wall (22 b) and the second end wall (22 c) of the tubular chamber (32) substantially parallel to the rotation axis (X) of the tubular chamber (32).

7. An electric heating device (1) according to claim 6, characterized in that the outlet (3 b) for heat transfer fluid is provided on the edge of the first end wall (22 b) or the second end wall (22 c).

8. An electric heating device according to claim 1, characterized in that the tubular cavity (32) is frustoconical.

9. An electric heating device (1) according to claim 1, characterized in that said inlet (3 a) of the heat transfer fluid is provided at a first end of said tubular cavity (32) and said outlet (3 b) of the heat transfer fluid is provided at a second end of said tubular cavity (32) opposite to said first end.

10. An electric heating device according to claim 1, characterized in that the turns of the inner spiral resistor (31 a) as a first resistor and/or the outer spiral resistor (31 b) as a second resistor have a constant pitch.