WO2025219031A1 - Electric water heater for a vehicle - Google Patents

Abstract

The invention relates to an electric water heater (1) for a vehicle, comprising at least one heating body (2) which surrounds an electric heating element (4), the heating body (2) being delimited by a first face (6) and by a second face (8) opposite the first face (6), the heating body (2) comprising at least one recess (14) which opens onto the first face (6) and at least one second recess (16) which opens onto the second face (8), the heating element (4) being arranged in the heating body (2) between the first recess (14) and the second recess (16), the heating body (2) comprising at least one passage (18) connecting the first recess (14) to the second recess (16).

Description

DESCRIPTION

Title of the invention: Electric water heater for vehicle

The present invention relates to the field of electric water heaters, and more specifically to electric water heaters for vehicles. Typically, a vehicle is equipped with one or more electric water heaters intended to heat a heat transfer fluid, which may for example be glycol or a mixture of glycol and water.

These electric water heaters have various applications. Electric water heaters are used in vehicle interior heating systems to heat the heat transfer fluid, which then heats the air inside the vehicle, and, for example, to heat a heat transfer fluid that heats the vehicle's electric battery.

The operation of these water heaters is based on the circulation of the heat transfer fluid within them. A key component of the electric water heater is its heating element, which is electrical in nature and usually uses a resistive material. The resistive material, once energized by an electric current, heats the rest of the heating element, which in turn transmits its heat, for example, to a heating element of the electric water heater placed in contact with the heating element. This process therefore allows the heat transfer fluid to heat up by passing through the water heater and being in direct contact with the heating element.

However, electric water heaters can have certain limitations. For example, they are prone to heat transfer fluid leaks, leading to the risk of the heat transfer fluid coming into contact with the electric water heater's electronic components. Furthermore, their design often requires many components, which can complicate their assembly. Additionally, traditional electric water heaters can suffer from heat loss to the outside environment, thus reducing the efficiency of heat transfer to the heat transfer fluid.

There is therefore a need for electric water heaters aimed at overcoming at least one of the shortcomings of existing water heaters.

According to one aspect of the invention, the electric water heater is equipped with a heating body which includes a heating element and which comprises at least a first recess and a second recess, the latter being connected by at least one passage, first recess, second recess and passage being intended to be traversed by a heat transfer fluid. The second recess, the first recess and the passage form a heat transfer fluid circuit minimizing heat losses to the outside. In addition, the heating body, by enclosing the heating element, reduces the risk of leakage of the heat transfer fluid and allows the formation of the heat transfer fluid circuit with a limited number of components.

One aspect of the invention relates to an electric water heater for a vehicle comprising at least one heating body which surrounds an electric heating element, said heating body being delimited by a first face and by a second face opposite the first face, the heating body comprising at least one recess which opens onto the first face and at least one second recess which opens onto the second face, the heating element being arranged in the heating body between the first recess and the second recess, the heating body comprising at least one passage connecting the first recess to the second recess.

The term “first recess” refers to the recesses on the first face, the term “second recess” refers to the recesses on the second face.

This is a name and therefore not a numbering.

The role of the heating body is to transmit the heat emitted by the heating element. To do this, it is made of a heat-conducting material. In this way, the heating element generates heat which is then transmitted to the heating body. The latter can then transfer this heat, for example, to a heat transfer fluid in contact with the heating body and this transfer is done by bringing the heat transfer fluid into contact with a first wall of the heating body delimiting the second recess and with a second wall of the heating body which delimits the first recess, above and below the heating element.

In order to maximize the efficiency of heat transmission, the heating body surrounds the heating element. For example, it is overmolded around the heating element, so that the latter can transfer its heat to the heating body in the most efficient way possible. When the heating element has a tubular shape, the heating body is preferably designed to cover the entire circumference of the heating element over at least a portion of the heating element, in order to maximize heat absorption. The overmolded nature of the heating body around the heating element ensures physical contact between the constituent material of the heating body and the external peripheral wall of the electric heating element.

The first face and the second face of the heating body are two opposite surfaces, in this example located in parallel planes and having for example substantially the same area. They are arranged in such a way that, when a straight line is drawn to connect the center of the first face with that of the second face, this line would be perpendicular to each of the faces. However, alternatively, the planes of the opposite faces are not parallel and, more generally, these faces have a shape of any suitable type and are not necessarily flat. The flat shape facilitates manufacturing and sealing.

The first recess, the second recess and the passage are hollow structures formed in the heating body, resulting from the molding operation of the heating body. The first recesses are formed from the first face, the second recesses are formed from the second face and the passages are formed in the material of the heating body by connecting the first recesses to the second recesses.

According to an optional feature of the invention, the passage is arranged at the end of the first recess and/or at the end of the second recess. The end of the first recess and the end of the second recess correspond respectively to one end of the first recess in a direction in which the first recess extends predominantly and to one end of the second recess in another direction in which the second recess extends predominantly.

Preferably, the at least one first recess, the at least one passage and the at least one second recess form a spiral conduit, preferably around the at least one heating element of the heating body.

The heating element is arranged in the core of the heating body material, being spatially arranged between the first recess and the second recess. It should also be understood that the heating element is in the heating body material without protruding into either the second recess, the first recess, or the passage. According to an optional feature of the invention, the first recess extends along a first main extension axis, the second recess extending along a second main extension axis, the first extension axis and the second extension axis being intersecting with respect to each other. It is understood here that the second recess and the first recess intersect at the passage.

The term "first extension axis" refers to the extension axis of a first recess and the term "second extension axis" refers to the extension axis of a second recess. It is therefore a name and not a numbering.

According to an optional feature of the invention, the electric water heater comprises a plurality of first recesses and second recesses, at least some of the first recesses being parallel or of constant spacing between them, and/or at least some of the second recesses are parallel or of constant spacing between them.

According to an optional feature of the invention, the first face comprises a plurality of first recesses which each extend along a first main extension axis, the main extension axis of at least one of the first recesses being parallel to the main extension axis of at least one other first recess. At least two first recesses are parallel. According to a particular example, all the first recesses are parallel to each other.

According to an optional feature of the invention, the second face comprises a plurality of second recesses which each extend along a second main extension axis, the second main extension axis of at least one of the second recesses being parallel to the second main extension axis of at least one other second recess. At least two second recesses are parallel. According to a particular example, all the second recesses are parallel to each other.

When there are a plurality of second recesses and a plurality of first recesses, each of the first recesses extends intersectingly to at least one second recess. This allows, as mentioned previously, for a first recess to be connected by one passage to a first "second recess" and by another passage to a second "second recess" immediately adjacent to the first "second recess". Thus, when there are a plurality of second recesses and a plurality of first recesses, there is also a plurality of passages. Furthermore, when the heating body comprises several first recesses, second recesses and passages, the heat transfer fluid is in contact with a large surface of the heating body which comprises the heating element. In this way, there is therefore a large heat exchange surface with said heat transfer fluid.

According to an optional characteristic of the invention, the heating body comprises at least a first port and a second port, the first port opening for example into the first recess while the second port opening for example into the second recess.

The first port and the second port allow either to introduce or to evacuate the heat transfer fluid which circulates in the heating body through the first recess, the passage and the second recess. When the first port is used as a heat transfer fluid inlet and the second port as a heat transfer fluid outlet, then the heat transfer fluid enters through the first port and arrives in this example directly in the first recess which communicates with the first port. Then, it passes through at least one passage, travels through the second recess and leaves the water heater through the second port. Conversely, when the first port serves as a heat transfer fluid outlet and the second port as an inlet, then the heat transfer fluid enters through the second port and is directed into the second recess which contains the second port. It then passes through at least one passage before exiting through the first recess which contains the first port. More generally, the first port opens into a first recess or into a second recess and the second port opens into a first recess or into a second recess.

If the heating body comprises a plurality of first recesses, second recesses and passages, the heat transfer fluid, after entering, circulates through this multitude of first recesses, second recesses and passages.

According to an optional characteristic of the invention, the heating element comprises at least one tube containing at least one electrical resistor, at least part of the tube being surrounded by the heating body, the material of the heating body which surrounds the tube being in contact with the entirety of an external periphery of said tube.

The electrical resistor generates heat when a current passes through it. The tubing, which surrounds this resistor, conducts the heat from the electrical resistor to the body of heating. Therefore, the tubing material must have good heat transmission capacity. It can, for example, be made of stainless steel, such a material being particularly suitable for establishing physical contact between the overmolded material of the heating body and the tubing itself.

It is interesting to note that the heating element is in contact with the entire outer periphery of the tubing. This means that, at least on a portion of the heating element, the heating element touches the entire outer periphery of the tubing. This outer periphery corresponds to the circumference of the tubing.

According to an optional feature of the invention, the heating element comprises a first end and a second end, at least one of these ends projecting from the first face.

Thus the first end and the second end can protrude from the first face in order to be able to electrically connect these ends, for example, to a control module. This makes it possible to control the production of calories from this heating element, and thus to regulate the temperature of the heating body as well as the temperature to which the heat transfer fluid circulating in the heating body is heated.

According to an alternative of the invention, the heating element comprises a first end which projects from the first face and a second end which projects from the second face.

According to an optional feature of the invention, the electric water heater comprises a heat transfer fluid circuit, said circuit comprising at least the first recess, at least the passage and at least the second recess. The heat transfer fluid circuit also comprises the first port and the second port. When there are a plurality of first recesses, second recesses and passages, the heat transfer fluid circuit therefore comprises the first port, the second port, the plurality of first recesses, the plurality of passages and the plurality of second recesses.

According to an optional feature of the invention, the electric water heater comprises a housing pressed against the first face and which delimits at least the first recess. The arrangement of the housing closes the first recess and allows the heat transfer fluid to be channeled within the heating body. Indeed, by delimiting the first recess, it a closed space is formed where the heat transfer fluid can then circulate in the first recess without exiting through the first face.

According to an optional feature of the invention, the electric water heater comprises a control module for the heating element, said control module being arranged in the housing. In this case, the control module can be connected to the first end of the heating element and/or to the second end of the heating element in order to control the temperature of the heating element. For this, the housing can comprise one or more orifices in order to pass the first end and the second end into the housing and to electrically connect them to the control module.

According to an optional feature of the invention, the electric water heater comprises a cover pressed against the second face and which delimits at least the second recess. The arrangement of the cover closes the second recess and allows the heat transfer fluid to be channeled within the heating body. Indeed, by delimiting the second recess, a closed space is formed where the heat transfer fluid can then circulate in the second recess without being able to exit through the second face.

According to an optional characteristic of the invention, the housing comprises a housing base surrounded by at least one edge, the housing base comprising at least one hollow formed opposite said recess.

The housing, when it includes hollows, allows, when the housing is pressed against the first face, to form a volume of the heat transfer fluid circuit which is greater than the volume of the heat transfer fluid circuit formed by the housing pressed against the first face when it does not include hollows.

According to an optional characteristic of the invention, the cover comprises a cover base surrounded on at least one side, the cover base comprising at least one boss provided opposite said first recess.

When the cover includes bosses, it allows, when said cover is pressed against the second face, to form a volume of the heat transfer fluid circuit which is greater than the volume of the heat transfer fluid circuit formed by the cover pressed against the second face when the cover does not include bosses. Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and examples of embodiment given for informational and non-limiting purposes with reference to the appended drawings on the other hand, in which:

[Fig. 1] is a perspective view of a heating body of an electric water heater.

[Fig. 2] is a view of a second face of the heating body according to the embodiment of Figure 1.

[Fig. 3] is a section along a plane A shown in Figure 1.

[Fig. 4] is a section along a plane B shown in Figure 1,

[Fig. 5] is a top view of the electric water heater according to the embodiment of the preceding figures, in which the electric water heater comprises the heating body, the heating element and a housing.

[Fig. 6] is a bottom view of the electric water heater according to the same embodiment as the previous figures.

[Fig. 7] is a section along a plane C shown in Figure 5.

The features and variants of the invention may be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and/or to differentiate the invention from the prior art.

In the figures, elements common to several figures retain the same reference.

Figure 1 is a view showing a first face of a heating body of an electric water heater, said heating body surrounding a heating element of the electric water heater.

The electric water heater 1 thus comprises the heating body 2 which encircles an electric heating element 4. More specifically, the heating body 2 is overmolded around this heating element 4. In this way, when the heating element 4 produces calories, the heating body 2 is able to transmit this heat by conduction. For this purpose, the heating element 2 is made of a material that provides good heat diffusion. A material such as aluminum is particularly suitable for this application.

The heating body 2 here has the shape of a rectangular parallelepiped and is therefore delimited by a first face 6 and a second face 8 opposite the first face 6. In addition, the heating body 2 is bordered by four walls, each wall connecting the first face 6 to the second face 8. The heating body 2 thus comprises two longitudinal walls 11, which correspond to the walls of larger surface area, and two transverse walls 12, which are walls of smaller surface area. According to one example, the two longitudinal walls 11 are parallel to each other and are arranged perpendicular to the two transverse walls 12. In other words, one of the longitudinal walls 11 is connected to the other longitudinal wall 11 by the two transverse walls 12.

In this embodiment, one of the transverse walls 12 is called the first transverse wall 26 for the sake of understanding for the remainder of the detailed description. The transverse wall 12 opposite the first transverse wall 26 is called the second transverse wall 28. Furthermore, one of the longitudinal walls is called the first longitudinal wall 27, while the longitudinal wall opposite the first longitudinal wall 27 is called the second transverse wall 29.

The heating body 2 also comprises at least one first recess 14 on the first face 6 and at least one second recess 16 on the second face 8. In this figure, the second face 8 and the second recesses 16 are not visible but will be described later in the detailed description of the following figures.

More particularly, in this embodiment the heating body 2 comprises four first recesses 14. These first recesses 14 open onto the first face 6, it should thus be understood that they each form a recess in the material of the heating body 2 from the first face 6.

Each of these four first recesses 14 extends along first main extension axes denoted “a” in FIG. 1. It should thus be understood that each recess 14 comprises its own main extension axis “a” and extends mainly along this axis. These main extension axes “a” extend from the first longitudinal wall 27 to the second longitudinal wall 29. The axes first main extensions “a” are thus arranged parallel to the transverse walls 12. In addition, the first main extension axes “a” of each of the first four recesses 14 are parallel to each other.

According to the invention, the heating body 2 also comprises at least one passage 18 which makes it possible to connect a recess 14 to a second recess 16. In this embodiment, the heating body 2 comprises several passages 18. Although the second recesses 16 are not visible in this figure, the passages 18 are.

Each of the first recesses 14 communicates fluidically with at least one passage 18. These passages 18 are arranged at the end of the first recesses 14, in the direction of the first main extension axes “a”. It should thus be understood that the passages 18 are located at at least one end of the first recesses 14, in the direction of the main extension axis “a”. In this way, the passages 18 are at least partly bordered by a longitudinal wall 11 of the heating body 2 and by an intermediate zone 19 of the heating body, the latter being constituted by the material of the heating body arranged between a second recess 16 and at least two adjacent first recesses 14.

One of the first four recesses 14, subsequently called the first first recess 20, has only one passage 18. This single passage 18 is therefore arranged at one end of the first first recess 20 in the direction of its main extension axis “a”. Furthermore, the heating body 2 comprises a first port 22 connected to this first first recess 20. More precisely, the first port 20 is positioned on the first longitudinal wall 27 and opens at one end of the first first recess 20 opposite, in the direction of the main extension axis “a”, at the end where the passage 18 of the first first recess 20 is located. The first port 22 thus comprises an opening in the first longitudinal wall 27 and opens here into this first first recess 20, this first port forming a portion of conduit between this opening and the zone where it opens into the first first recess 20.

A second port 24 is also present on the first longitudinal wall 27. This second port 24 differs from the first port 22 in that it opens here into one of the second recesses 16. This characteristic will be detailed in the description of the following figures. The first recess 20 is arranged immediately adjacent to the first transverse wall 26. It is therefore the first recess 14 positioned closest to the first transverse wall 26.

The first first recess 20 is delimited by a recess bottom 30 which extends from the first port 22 to the passage 18. In this way, when a heat transfer fluid is introduced through the first port 22, it is guided by the recess bottom 30 to the passage 18 of the first first recess 20, which then allows it to pass from the first first recess to the immediately adjacent second recess with which the first recess communicates fluidically.

The other first recesses 14 fluidly communicate with two passages 18 each and also each include a recess bottom 30. Thus, in each of these first recesses 14, a first passage 18 is positioned at one end of the first recess, and a second passage 18 is positioned at an opposite end of the first recess. It should be noted that these are ends in the direction of the first main extension axis “a”. The heat transfer fluid arriving from a second recess 16 and passing through a passage 18 and thus guided by the recess bottom 30 towards the other passage 18 in order to supply an adjacent second recess 16.

The heating element 4 comprises a tube 32 itself surrounding an electrical resistor 34. The tube 32 is made of a material capable of correctly transferring the heat from the electrical resistor 34 to the heating body 2, for example stainless steel, while protecting this electrical resistor 34 against attacks, in particular during the operation of molding the heating body 2.

This heating element 4 has a first end 36 and a second end 38. These two ends are parts of the heating element 4 which are not surrounded by the heating body 2. Thus, these ends can be connected, for example, to electrical or electronic devices such as a control module making it possible to supply and control an electric current to the electrical resistance 34.

The first end 36 and the second end 38 emerge here from the heating body 2 via the first face 6, more precisely by passing through a solid zone 40 of the heating body 2 which does not include a recess 14 or a second recess 16. This solid zone 40 of the heating body 2 is shown in dotted lines in FIG. 1 and thus corresponds to a location of the heating body 2 where the material extends without discontinuity from the first face 6 and the second face 8. Said solid zone 40 is positioned between the second transverse wall 28 and the first recess 14 closest to this second transverse wall 28. The first end 36 of the heating element 4 and the second end 38 of the heating element 4 thus open out from the first face 6 at the level of this solid zone 40.

A passage 18 has an oblong section. The heating body 2 here comprises two groups of several passages 18, the passages 18 of the same group being aligned along the same straight line, for example parallel to one of the longitudinal walls 11 of the heating body 2.

Figure 2 is a view of the second face 8 of the heating body 2 according to the embodiment of Figure 1.

The heating body 2 therefore comprises at least one second recess 16. More particularly, the heating body comprises four second recesses 16. Each of these four second recesses 16 opens onto the second face 8 and communicates fluidically with at least one passage 18 connecting a second recess 16 to a recess 14.

The second recesses 16 each extend along a second main extension axis denoted “d” in FIG. 2. These second main extension axes “d” extend from the first longitudinal wall 27 of the heating body to the second longitudinal wall 29 of the heating body 2. In this embodiment, each of the second main extension axes “d” are parallel to each other, thus each second recess 16 extends parallel to each other and extends from the first longitudinal wall 27 to the second longitudinal wall 29.

The second main extension axis “d” of each of the second recesses 16 extends in a secant manner relative to the main extension axes “a” of the first recesses 14. By intersecting, the second main extension axes “d” and the first main extension axes “a” then form an angle a of a non-zero value. Thus, unlike the first main extension axes “a” which extend parallel to the transverse walls 12, the second main extension axes “d” also form a non-zero angle with respect to the transverse walls 12.

The heating body 2 comprises a recess 16 which is hereinafter called the second end recess 42. This second end recess 42 comprises only one passage 18. More precisely, the second end recess 42 is connected to the first recess 14 positioned closest to the second transverse wall 28. The second end recess 42 is also the second recess 16 closest to the second transverse wall 28.

Furthermore, this second end recess 42 is connected to the second port 24 positioned on the first longitudinal wall 27. The second port 24 thus comprises an opening in this first longitudinal wall 27 which opens into the second end recess 42. This second port 42 is in this way arranged at the end of the second end recess 42, that is to say at its end in the direction of said second main extension axis “d”. Furthermore, the second port 42 forms a portion of conduit between this opening and the area where it opens into the second end recess 42.

The single passage 18 of the first cavity 42 is arranged at the other end of the first cavity 42, that is to say at the opposite end, in the direction following the second main extension axis “d”, at the end where the second port 24 is positioned.

The three other second recesses 16 comprise between them two passages 18. One passage 18 is positioned at one end of each of these cavities 16 while the other passage 18 is located at the other end of each of these cavities 16, that is to say that the three other second recesses 16 comprise a passage 18 arranged at each of their ends, in the direction following the main extension line “d”.

Each of the second recesses 16 also comprises a second recess bottom 44, connecting, in the second end recess 42, the second port 24 to the passage 18 of the second end recess 42, and in the other second recesses 16 connecting the two passages 18 of each of these second recesses 16. It should be noted that the first recess bottoms 30 and the second recess bottoms recess 44 at least partially delimit the intermediate zone 19 of the heating body 2

Figure 3 is a section along a plane A shown in Figure 1. This section allows one to observe a recess 14, a second recess 16 and their arrangements within the heating body 2.

Figure 3 illustrates that a first recess 14, a second recess 16 and a passage 18 form a heat transfer fluid circuit 84. It should thus be understood that the heat transfer fluid circulates within this heat transfer fluid circuit 84, that is to say that it circulates within at least a first recess 14, a second recess 16 and a passage 18.

The first recess 14 illustrated in this figure is thus delimited transversely by the two longitudinal walls 11 and by the bottom 30 of the first recess 14. Similarly, the second recesses 16 are delimited by the bottom 44 of the second recess 16 and by the two longitudinal walls 11.

The first recesses 14, the second recesses 16 and the passages 18 partly delimit the intermediate zone 19 of the heating body 2. Since it is part of the heating body 2, this intermediate zone 19 is composed of the material constituting the heating body 2.

The heating element 4 is surrounded by the intermediate zone 19, which in turn is surrounded by the second recesses 16, the passages 18 and the first recesses 14. Consequently, when the heating element 4 produces calories, it heats the intermediate zone 19, which in turn heats the heat transfer fluid circulating in the first recesses 14, the passage 18 and the second recesses 16.

In this way, the intermediate zone 19 only heats the heat transfer fluid and therefore does not heat the longitudinal walls 11. This makes it possible to avoid heat losses and thus minimize heat dissipation towards the environment outside the electric water heater according to the invention.

Figure 4 is a section along a plane B shown in Figure 1, this section allowing the arrangement of the heating element 4 in the intermediate zone 19 of the heating body 2 to be observed. The heating element 4 is arranged to wind through the intermediate zone 19 of the heating body 2, which makes it possible to heat a significant portion of this intermediate zone 19 and, consequently, to heat the heat transfer fluid correctly. More precisely, the heating element 4 is positioned to pass opposite the passages 18. The passages 18 thus form a heat recovery barrier, in which the heat is transmitted to the fluid circulating in the passages 18 rather than dissipated into the air via the longitudinal walls 11.

Furthermore, the heating element 4 makes several round trips in the intermediate zone 19, thus maximizing the heating of the intermediate zone 19 and ensuring that all the heat transfer fluid contained in the first recesses 14, the second recesses 16, and the passages 18 is correctly heated.

More precisely, the heating element 4, located within the intermediate zone 19, comprises a first rectilinear portion 66. This first rectilinear portion 66 is followed by a first elbow 68, which is itself followed by a second rectilinear portion 70. Then, this second rectilinear portion 70 is followed by a second elbow 72. This second elbow 72 leads to a third rectilinear portion 74, which is itself followed by a first half-turn 76. This first half-turn 76 precedes a fourth rectilinear portion 78, which is then followed by a second half-turn 80. Finally, this second half-turn 80 is followed by a fifth rectilinear portion 82.

It should be noted that, in this embodiment, the first, third and fifth rectilinear portions are parallel to at least one longitudinal wall 11. Figure 5 is a top view of the electric water heater according to the embodiment of the preceding figures, in which the electric water heater comprises the heating body, the heating element and a housing.

The electric water heater 1 comprises, in addition to the heating body 2 and the heating element 2, a housing 50. This housing 50 is provided with a housing base 52 and at least one edge 54. The housing base 52 is specifically designed to accommodate various electrical and electronic components, including, but not limited to, a control module 55 for the heating element and devices for measuring the temperature of the heat transfer fluid.

In this embodiment, the case bottom 52 is surrounded by four edges 54. These edges 54 delimit a rectangular shape, which corresponds substantially to the shape of the heating body 2. Thus, two of these edges 54 are parallel to at least one transverse wall 12, while the other two edges 54 are parallel to at least one longitudinal wall 11. In this housing bottom 52 there is an orifice 56, for example of oblong shape. This orifice 56 passes completely through the bottom of the housing 52 and is intended to allow the passage of the first end 36 and the second end 38 of the heating element 4. In this way, the heating element 4 can for example be electrically connected to the control module 55 located in this housing bottom 52.

The housing 50 is pressed against the first face 6 of the heating body 2 so as to cover the first recesses 14 and thus create a sealed space with the first recesses 14 formed in the heating body 2. When the heat transfer fluid circulates inside the first recesses 14, it cannot therefore escape through the first face 6 and is forced to continue its path through the first recesses 14.

Figure 6 is a bottom view of the electric water heater according to the same embodiment as the previous figures. It can thus be seen in this figure that the electric water heater also comprises a cover 58.

This cover 58 comprises a cover base 60 and at least one side 62. The cover base 60 is pressed against the second face 8 so as to form a sealed space with the second recesses 16 provided in the heating body 2. Thus, when the heat transfer fluid circulates in a second recess 16, the heat transfer fluid cannot escape through the second face 8 and therefore continues its path in the second recess 16.

When the heating body 2 has a rectangular shape, the cover 58 can, for example, adopt a trapezoidal shape. In this embodiment, the cover 58 thus has a trapezoidal shape, meaning that it is composed of four sides 62, among which two sides 62 are parallel to the main extension line “d” and two other sides 62 are parallel to at least one longitudinal wall 11. The cover base 60 comprises at least one boss 64. In this embodiment the number of bosses 64 is equal to the number of second recesses 16 of the heating body 2, there are thus four bosses 64. Each of these bosses 64 extends mainly in the direction followed by one of the main extension lines “d”.

Figure 7 is a section along a plane C shown in Figure 5. The electric water heater is thus shown with its heating body 2, the box 50 and the cover 58 so as to be able to observe the interaction of the housing 50 and the cover 58 with the heating body 2.

The housing bottom 56 comprises recesses 64 formed in said housing bottom 56. When the housing 50 is pressed against the first face 6, the recesses 64 are arranged in such a way that they correspond to the first recesses 14 of the first face 6. It is understood here that a recess 64 extends entirely opposite a recess 14. By positioning the housing 50, a part of the heat transfer fluid circuit 84 is thus formed, delimited at least in part by the first recesses 14 and the recesses 64. The recesses 64 are designed to form a section of the heat transfer fluid circuit 84 larger than when this section was formed solely by the first recesses 14 and the housing 50, in the absence of recesses 64.

The cover 58, for its part, cooperates with a joint plane surrounding the second recesses 16, which allows said cover 58 to be pressed against the second face 8. The cover 58 comprises bosses 66. These bosses 66 participate in forming another section of the heat transfer fluid circuit 84, delimited by the bosses 66 and the second recesses 16. The bosses 66 serve to increase the volume of this section of the heat transfer fluid circuit 84 compared to a configuration where the cover 58 would be devoid of such bosses 66.

The heat transfer fluid circuit 84 thus allows the heat transfer fluid to circulate around the intermediate zone 19 of the heating body 2. This heat transfer fluid circuit 84 is formed by the hollows 64 of the housing 50, the bosses 66 of the cover 58, the first recesses 14, the second recesses 16 and the passages 18.

The present invention thus provides an electric water heater comprising a heating body surrounding a heating element and comprising first recesses, second recesses and passages connecting at least one recess to a second recess. This organization of the heating body forms a heat transfer fluid circuit making it possible to efficiently heat said heat transfer fluid while avoiding heat loss to the external environment.

The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically effective combination of such means.

Claims

CLAIMS: 1. Electric water heater (1) for a vehicle comprising at least one heating body (2) which surrounds an electric heating element (4), said heating body (2) being delimited by a first face (6) and by a second face (8) opposite the first face (6), the heating body (2) comprising at least one first recess (14) which opens onto the first face (6) and at least one second recess (16) which opens onto the second face (8), the heating element (4) being arranged in the heating body (2) between the first recess (14) and the second recess (16), the heating body (2) comprising at least one passage (18) connecting the first recess (14) to the second recess (16). 2. Electric water heater (1) according to claim 1, wherein the passage (18) is arranged at the end of the first recess (14) and/or at the end of the second recess (16). 3. Electric water heater (1) according to claim 2, wherein the at least one first recess (14), the at least one passage (18) and the at least one second recess (16) form a spiral conduit, preferably around the at least one heating element (4) of the heating body (2). 4. An electric water heater (1) according to any preceding claim, wherein the first recess (14) extends along a first main extension axis (a), the second recess (16) extending along a second main extension axis (d), the first main extension axis (a) and the second main extension axis (d) intersecting each other. 5. An electric water heater (1) according to any preceding claim, comprising a plurality of first recesses (14) and second recesses (16), wherein at least some of the first recesses (14) are parallel or of constant spacing between them and/or at least some of the second recesses (16) are parallel or of constant spacing between them. 6. An electric water heater (1) according to claim 5, wherein the first face (6) comprises a plurality of first recesses (14) each extending along a first main extension axis (a), said first main extension axis (a) of at least one of the first recesses (14) being parallel to said first main extension axis (a) of at least one other first recess (14). 7. Electric water heater (1) according to claim 5 or 6, wherein the second face (8) comprises a plurality of second recesses (16) which each extend along a main extension line (d), the main extension line (d) of at least one of the second recesses (16) being parallel to the main extension line (d) of at least one other second recess (16). 8. Electric water heater (1) according to any one of the preceding claims, in which the heating body (2) comprises at least a first port (22) and a second port (24), the first port (22) opening for example into the first recess (14) and/or the second port (24) opening for example into the second recess (16). 9. Electric water heater (1) according to any one of the preceding claims, in which the heating element (4) comprises at least one tube (32) containing at least one electrical resistance (34), at least a part of the tube (32) being surrounded by the heating body (2), the material of the heating body (2) which surrounds the tube (32) being in contact with the entirety of an external periphery of said tube (32). 10. Electric water heater (1) according to any one of the preceding claims, in which the heating body is overmolded around the heating element (4)- 11. Electric water heater (1) according to any one of the preceding claims, wherein the heating element (4) comprises a first end (36) and a second end (38), at least one of these ends (36, 38) projecting from the first face (6). 12. Electric water heater (1) according to any one of the preceding claims, comprising a heat transfer fluid circuit (84), said circuit (84) comprising at least the first recess (14), at least the passage (18) and at least the second recess (16). 13. Electric water heater (1) according to any one of the preceding claims, comprising a housing (50) pressed against the first face (6) and which delimits at least the first recess (14). 14. Electric water heater (1) according to the preceding claim, comprising a control module (55) for the heating element (4), said control module (55) being arranged in the housing (50). 15. Electric water heater (1) according to any one of the preceding claims, comprising a cover (58) pressed against the second face (8) and which delimits at least the second recess (16). 16. Electric water heater (1) according to any one of claims 13 to 15, in which the housing (50) comprises a housing base (52) surrounded by at least one edge (54), the housing base (52) comprising at least one hollow (64) formed opposite said recess (14). 17. Electric water heater (1) according to any one of claims 14 to 16, in which the cover (58) comprises a cover base (60) surrounded by at least one side (62), the cover base (60) comprising at least one boss (66) arranged opposite said second recess (16).