U.S. patent application number 10/548606 was filed with the patent office on 2007-02-15 for conditioning system for cooling and heating surfaces, particularly automobile seats.
Invention is credited to Christian Bier, Stefan Kerscher.
Application Number | 20070035162 10/548606 |
Document ID | / |
Family ID | 32798781 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070035162 |
Kind Code |
A1 |
Bier; Christian ; et
al. |
February 15, 2007 |
Conditioning system for cooling and heating surfaces, particularly
automobile seats
Abstract
A temperature control mat 5 is described, in particular for the
rapid cooling of a vehicle seat covering 4. The temperature control
mat comprises at least two interconnected thin films of plastic 5a,
5b, forming a fluid chamber system 10, and openings 11 distributed
over the temperature control mat which penetrate through the
temperature control mat 5. For temperature control, initially a
temperature control fluid is directed through the fluid chamber
system. Subsequently, the system is emptied and an air stream is
directed through a spacing structure 6, in order to dissipate
moisture passing through the openings 11.
Inventors: |
Bier; Christian; (MIESBACH,
DE) ; Kerscher; Stefan; (Munich, DE) |
Correspondence
Address: |
Dianne Burkhard;W L Gore & Associates Inc
551 Paper Mill Road
PO Box 9206
Newark
DE
19714-9206
US
|
Family ID: |
32798781 |
Appl. No.: |
10/548606 |
Filed: |
March 5, 2004 |
PCT Filed: |
March 5, 2004 |
PCT NO: |
PCT/EP04/02268 |
371 Date: |
August 14, 2006 |
Current U.S.
Class: |
297/180.15 ;
165/138 |
Current CPC
Class: |
B60N 2/56 20130101; B60N
2/5635 20130101; B60H 1/00285 20130101; B60H 2001/00307 20130101;
B60N 2/5657 20130101 |
Class at
Publication: |
297/180.15 ;
165/138 |
International
Class: |
A47C 31/00 20060101
A47C031/00; F28F 7/00 20060101 F28F007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 6, 2003 |
EP |
03004905.0 |
Claims
1. A temperature control mat (5), in particular for use in a seat
element (2) and/or rest element (3), comprising: at least two
layers of liquid-impermeable plastic (5a, 5b), which are connected
to each other in such a way that they form a fluid chamber system
in between; at least one fluid inlet (13) and at least one fluid
outlet (14) for directing a fluid through the fluid chamber system;
and openings (11), which are arranged in a distributed manner in
the at least two layers of plastic (5a, 5b) and penetrate the
latter in such a manner that water vapor can pass through the
openings (11) past the fluid chamber system.
2. The temperature control mat as claimed in claim 1, the openings
(11) forming 20% to 80% of the projected surface area of the
interconnected layers of plastic (5a, 5b).
3. The temperature control mat as claimed in claim 2, the fluid
chamber system having a maximum volume of 0.3 l/m.sup.2 to 3
l/m.sup.2.
4. The temperature control mat as claimed in claim 1, the openings
(11) having an average diameter in the range from 1 mm to 20
mm.
5. The temperature control mat as claimed in claim 2, the openings
(11) having an average diameter in the range from 1 mm to 20
mm.
6. The temperature control mat as claimed in claim 1, the at least
two layers of plastic (5a, 5b) being connected to each other in
such a way that, when the fluid chamber system is filled with a
fluid, the maximum distance between the at least two layers of
plastic lies in the range from 0.5 mm to 10 mm.
7. The temperature control mat as claimed in claim 2, the at least
two layers of plastic (5a, 5b) being connected to each other in
such a way that, when the fluid chamber system is filled with a
fluid, the maximum distance between the at least two layers of
plastic lies in the range from 0.5 mm to 10 mm.
8. The temperature control mat as claimed in claim 3, the at least
two layers of plastic (5a, 5b) being connected to each other in
such a way that, when the fluid chamber system is filled with a
fluid, the maximum distance between the at least two layers of
plastic lies in the range from 0.5 mm to 10 mm.
9. The temperature control mat as claimed in claim 1, the at least
two layers of plastic (5a, 5b) being connected to each other in
such a way that the fluid chamber system is subdivided into a
number of chambers (10), each chamber (10) defining a fluid
passage.
10. The temperature control mat as claimed in claim 3, the at least
two layers of plastic (5a, 5b) being connected to each other in
such a way that the fluid chamber system is subdivided into a
number of chambers (10), each chamber (10) defining a fluid
passage.
11. The temperature control mat as claimed in claim 9, the fluid
passages being formed with an average length in the range from 3 mm
to 15 mm.
12. The temperature control mat as claimed in claim 9, a number of
or all the fluid passages being connected to a common fluid
distributing chamber (13a) and/or fluid collecting chamber
(14a).
13. The temperature control mat as claimed in claim 11, a number of
or all the fluid passages being connected to a common fluid
distributing chamber (13a) and/or fluid collecting chamber
(14a).
14. The temperature control mat as claimed in claim 11, one or more
common fluid inlets and outlets being provided.
15. The temperature control mat as claimed in claim 1, a single
fluid inlet (13) and a single fluid outlet (14) being provided for
the entire temperature control mat.
16. The temperature control mat as claimed in claim 9, a single
fluid inlet (13) and a single fluid outlet (14) being provided for
the entire temperature control mat.
17. The temperature control mat as claimed in claim 1, each of the
at least two layers of plastic having a thickness in the range from
10 .mu.m to 1 mm.
18. The temperature control mat as claimed in claim 11, the
thickness of each of the at least two layers of plastic being
approximately 200 .mu.m.
19. The temperature control mat as claimed in claim 1, at least one
of the at least two layers of plastic being air-permeable, at least
in certain regions.
20. The temperature control mat as claimed in claim 1, at least one
of the layers of plastic consisting of thermoplastic polyurethane
(TPU).
21. The temperature control mat as claimed in claim 1, at least one
of the layers of plastic consisting of a fluoropolymer.
22. The temperature control mat as claimed in claim 20, at least
one of the layers of plastic consisting of a fluoropolymer.
23. The temperature control mat as claimed in claim 21, the
fluoropolymer being polytetrafluoroethylene (PTFE).
24. The temperature control mat as claimed in claim 23, the PTFE
being compressed, expanded polytetrafluoroethylene (ePTFE) with a
porosity in the range from 2% to 30%, in order to assist the
venting of the fluid chamber system.
25. A seat element (2) and/or rest element (3) with an outer
covering (4) and a cushion core (7) under the outer covering and
with a temperature control mat (5) positioned between the covering
(4) and the cushion core (7), as claimed in claim 1.
26. The seat element and/or rest element as claimed in claim 25, an
open spacer structure (6) being provided between the covering (4)
and the cushion core (7), in order to permit ventilation through
the spacer structure (6).
27. The seat element and/or rest element as claimed in claim 26,
the spacer structure (6) being positioned between the temperature
control mat (5) and the cushion core (7).
28. The seat element and/or rest element as claimed in claim 25,
the temperature control mat (5) not pressing visibly through the
surface of the outer covering (4).
29. The seat element and/or rest element as claimed in claim 25,
the cover (4) comprising a water-vapor-permeable leather
material.
30. The seat element and/or rest element as claimed in claim 29,
leather material having an MVTR value of over 10 mg/cm.sup.2h, in
particular greater than 12 mg/cm.sup.2h.
31. The seat element and/or rest element as claimed in claim 25,
the temperature control mat (5) being connected to the covering
(4).
32. The seat element and/or rest element as claimed in claim 25,
the spacer structure (6) being connected to the temperature control
mat (5).
33. A temperature control system comprising a seat element (2)
and/or rest element (3) as claimed in claim 25 and further
comprising a liquid circuit system, to which the temperature
control mat having one or more common fluid inlets and outlets, is
connected via the fluid inlet and outlet openings (13, 14).
34. The temperature control system as claimed in claim 33, further
comprising in the liquid circuit system a pump (P) downstream of
the outlet (14), in order to suck liquid through the fluid chamber
system, and an inlet shut-off valve (17) upstream of the inlet
(13), in order to interrupt the liquid flow into the fluid chamber
system.
35. The temperature control system as claimed in claim 33, further
comprising ventilation to produce an air stream over a surface of
the temperature control mat (5), in order to dissipate moisture and
vapor entering the seat element (2) and/or backrest element (3)
through the covering (4).
36. The temperature control system as claimed in claim 33, further
comprising a cooling device (15) in the liquid circuit system for
cooling the liquid.
37. The temperature control system as claimed in claim 33, the
cooling device (15) being set up such that the necessary power for
the cooling device can be provided by the vehicle's own
battery.
38. The temperature control system as claimed in claim 37, the
cooling device (15) being activatable by remote control or time
switches.
39. The temperature control system as claimed in claim 33, further
comprising a liquid reservoir (9), the cooling device (15) being
provided for cooling the liquid in the liquid reservoir (9).
40. The temperature control system as claimed in claim 39, further
comprising an insulation (16) for the liquid reservoir (9).
41. The temperature control system as claimed in claim 33, further
comprising a heating device (20) in the liquid circuit system for
heating the liquid.
42. The temperature control system as claimed in claim 36, further
comprising a heating device (20) in the liquid circuit system for
heating the liquid.
43. The temperature control system as claimed in claim 41, further
comprising a bypass line (18), through which the liquid in the
liquid circuit system is directed when the heating device (20) is
activated.
44. A vehicle seat comprising: a seat element (2) and/or rest
element (3) having an outer covering (4) and a cushion core (7)
under the outer covering; a temperature control mat (5) positioned
between the covering (4) and the cushion core (7), wherein the
temperature control mat (5), comprises: at least two layers of
liquid-impermeable plastic (5a, 5b), which are connected to each
other in such a way that they form a fluid chamber system in
between; at least one fluid inlet (13) and at least one fluid
outlet (14) for directing a fluid through the fluid chamber system;
and openings (11), which are arranged in a distributed manner in
the at least two layers of plastic (5a, 5b) and penetrate the
latter in such a manner that water vapor can pass through the
openings (11) past the fluid chamber system.
45. A vehicle seat as claimed in claim 44, further comprising a
temperature control system comprising a liquid circuit system, to
which the temperature control mat having one or more common fluid
inlets and outlets, is connected via the fluid inlet and outlet
openings (13, 14).
46. The vehicle seat as claimed in claim 45 having a temperature
control system further comprising a liquid reservoir (9), and a
cooling device (15) being provided for cooling the liquid in the
liquid reservoir (9), wherein the liquid reservoir (9) being
arranged underneath the vehicle seat.
47. A vehicle seat as claimed in claim 44 further comprising a
spacer structure (6) being positioned between the covering (4) and
the cushion core (7), in order to permit ventilation through the
spacer structure (6).
48. A method for controlling the temperature of a seat element
and/or rest element, the seat and/or rest element having an outer
covering (4) and, under the covering (4), a cushion core (7),
comprising: passing a cooling or heating fluid into a closed fluid
chamber system, which is positioned between the covering (4) and
the cushion core (7), so that the fluid chamber system fills with
the fluid; and when a setpoint temperature is reached at a
predetermined point of the seat and/or rest element, draining the
fluid from the fluid chamber system, whereby the fluid chamber
system empties.
49. The method as claimed in claim 48, wherein the fluid chamber
system inflates during filling and collapses during emptying.
50. The method as claimed in claim 48, the fluid being passed
constantly or intermittently through the fluid chamber system when
the fluid chamber system is filled with fluid.
51. The method as claimed in claim 48, further comprising the step
of producing an air stream over a surface of the fluid chamber
system.
52. The method as claimed in claim 48, the fluid being a
liquid.
53. The method as claimed in claim 48, comprising using a
temperature control system comprising a seat element (2) and/or
rest element (3) having an outer covering (4) and a cushion core
(7) under the outer covering, and a temperature control mat (5)
positioned between the covering (4) and the cushion core (7),
wherein the temperature control mat (5) comprises: at least two
layers of liquid-impermeable plastic (5a, 5b), which are connected
to each other in such a way that they form a fluid chamber system
in between; at least one fluid inlet (13) and at least one fluid
outlet (14) for directing a fluid through the fluid chamber system;
and openings (11), which are arranged in a distributed manner in
the at least two layers of plastic (5a, 5b) and penetrate the
latter in such a manner that water vapor can pass through the
openings (11) past the fluid chamber system, and further comprising
a liquid circuit system, to which the temperature control mat
having one or more common fluid inlets and outlets, is connected
via the fluid inlet and outlet openings (13, 14).
54. A method as claimed in claim 48 comprising providing an open
spacer structure (6)between the covering (4) and the cushion core
(7), in order to permit ventilation through the spacer structure
(6), comprising the step of directing an air stream through the
spacer structure (6) parallel to the covering (4).
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a temperature control system, which
can be used for the rapid cooling and possibly also heating of
surfaces--in particular of car seats. In addition, the invention
relates to a seat and/or rest element, in particular with leather
covering, and to a complete car seat, respectively fitted with such
a temperature control system. Finally, the invention also relates
to a temperature control mat for such a temperature control system
and to a temperature control method for cooling and possibly
heating a seat and/or rest element.
[0002] It is known not only to heat but also to cool seats--in
particular car seats. Cooling is necessary if car seats heat up
under strong solar irradiation to high temperatures, which can lead
to serious burns of the skin. This problem arises in particular in
the case of dark leather seats. In general, the driver must wait
until the seat has cooled down to a temperature comfortable for
sitting, whether by means of the car's air-conditioning system or
by means of natural ventilation. Therefore, a fundamental concern
is to lower the surface temperature of seats to a comfortable level
in a short time.
[0003] It is known from U.S. Pat. No. 6,003,950 to provide between
the seat covering and the cushion core a fiber-like insert which is
enclosed by a film. The part of the film which faces the seat
covering has openings for the passage of air. Air is then sucked
through the seat covering and the insert by means of a fan, in
order to cool the seat.
[0004] It is known from U.S. Pat. No. 6,254,179 B1 to arrange a
meandering system of hoselines or pipelines through which water
flows in a flat cushion underneath the seat covering, in order to
heat or cool the seat area according to requirements. The
temperature of the water in the lines is controlled by means of a
complex heat exchanger system, which is connected for example to
the vehicle's heating and air-conditioning system.
[0005] A system of a similar construction is also described in DE
44 32 497 A1. In this case, the pipeline system for the cooling
liquid is arranged in a temperature control mat between two layers
of air-permeable material, in order that condensed water possibly
occurring on the lines can dry. The temperature control mat may
serve as a seat support or be an integral component of the vehicle
seat.
[0006] Because of the relatively rigid nature of the hoses or
pipes, the system of lines undesirably presses through the seat
covering and adversely affects the feel of the seat. If the system
of lines is arranged further in the interior of the seat to remedy
this disadvantage, however, a significant reduction in efficiency
occurs because of the poor heat transfer associated with the
greater distance from the temperature-controlling surface.
[0007] It is disadvantageous, furthermore, that, in the case of the
previously described systems, no moisture resulting for example
from the perspiration of a person sitting on the surface is
removed. This may have the consequence on hot days of clothing
becoming soaked with perspiration.
[0008] Instead of a liquid, a gas may also be used for controlling
the temperature of the seat. Such a system is described for example
in U.S. Pat. No. 4,572,430. In this case, temperature-controlled
air is directed from the rear side into the seat and backrest
cushion. The seat covering is air-permeable, so that the air can
leave the seat again on the front side.
[0009] A similar system is proposed in U.S. Pat. No. 6,273,810 B1.
There, the temperature-controlled air is directed into air chambers
lying under the seat covering. Individual chambers are merely
inflated and serve exclusively for increasing the comfort of the
underlying structure of the seat. Other chambers are perforated on
their side facing the seat covering and serve for controlling the
temperature of the seat, in that the temperature-controlled air is
forced to the outside through the perforation of the air-chamber
wall and further through the seat covering, which is likewise
perforated.
[0010] Although no lines press through the seat covering in the
case of the two systems last described, the removal of moisture is
not ideal in these cases either, although a certain drying is
reliably achieved by the air stream emerging from the seat.
However, the person sitting on the seat closes the pores in the
seat, so that at these points the transporting of moisture and
exchange of air is virtually completely blocked. Moreover, the air
emerging from the open pores flows past the person, which is felt
to be uncomfortable and may be harmful to health, in particular in
the lumbar region.
[0011] In addition, perforated seat coverings, in particular made
of leather, have a tendency to become clogged with dust and dirt
particles and are also not desired for design reasons. A further
disadvantage is that the systems described only begin to work when
the car is started, i.e. the driver initially sits down on a hot
seat, before the cooling of the seat begins.
[0012] It is therefore the object of the present invention to
propose a solution for cooling heated-up surfaces--in particular of
car seats with leather coverings--to a comfortable temperature in a
very short time, and at the same time for ensuring efficient
transporting away of moisture, in particular perspiration, through
the seat covering. At the same time, sitting comfort and surface
appearance are to be maintained.
[0013] This object is achieved by a temperature control system or
temperature control mat and a method for controlling the
temperature of a seat and/or rest element with the features of the
independent patent claims. Advantageous developments and
refinements of the invention are specified in claims dependent on
these independent claims.
SUMMARY OF THE INVENTION
[0014] The temperature control mat according to the invention is,
on the one hand, air-permeable and, on the other hand, comprises a
fluid chamber system, through which a temperature control fluid is
directed. For this purpose, two or more layers of
liquid-impermeable plastic are connected to each other, for example
welded or adhesively bonded, in such a way that the fluid chamber
system is formed in the space between the layers of plastic. A
number of fluid chamber systems that are separated from one another
may also possibly be formed between the layers of plastic.
[0015] A fluid chamber system formed between the layers of plastic
comprises one or more fluid chambers for receiving the temperature
control fluid and one or more fluid inlets and outlets in
connection with the fluid chambers for supplying and removing the
temperature control fluid to and from the fluid chamber system. The
maximum volume of the fluid chamber system in one embodiment may be
0.3 l/m.sup.2 to 3 l/m.sup.2. Some or all of the fluid chambers of
the fluid chamber system are in flow connection with one another,
so that the temperature control fluid can flow from the fluid inlet
or the fluid inlets through the interconnected fluid chambers of
the fluid chamber system to the fluid outlet or the fluid outlets.
The connecting zones between the fluid chambers are referred to
hereafter as "fluid passages".
[0016] The air permeability of the temperature control mat is based
on openings arranged in a distributed manner passing through the
temperature control mat. These openings pass through the layers of
plastic forming the fluid chamber system in such a way that the
fluid chamber system forms a closed system.
[0017] To ensure the transporting of moisture through the seat
covering, the temperature control mat is combined with an open
spacer structure. Any two-dimensional, open structure which on the
one hand permits a through-flow of gas to dissipate water vapor
passing through the seat covering and on the other hand is
adequately flexible and nevertheless stable under pressure, so that
it does not collapse even under the weight of a person imparting a
load to it, can be used as the spacer structure. The spacer
structure may be securely connected to the temperature control mat,
for example sewn or preferably adhesively bonded, so that the
temperature control mat including the spacer structure can be
easily handled and integrated into a seat. The spacer structure
preferably lies between the temperature control mat and the seat
cushion, so that the sequence of the layer structure is as follows:
seat covering, temperature control mat, spacer structure, seat
cushion, and any additional layers lying inbetween.
[0018] This arrangement is particularly effective, because the
temperature control mat lies directly underneath the seat covering.
This produces great heat conduction and short diffusion paths for
water vapor. The perspiration moisture passing through the seat
covering then passes through the openings in the temperature
control mat and into the open spacer structure and can be diffused
away from there. The transporting away of the moisture is
preferably assisted by an air stream, which is directed through the
spacer structure parallel to the surface of the seat covering, in
order to remove the transmitted moisture actively. The temperature
control mat on one side of the spacer structure and the seat
cushion, usually consisting of closed-cell foam, on the other side
of the spacer structure in this case define an air-directing duct
for the air directed through the spacer structure.
[0019] It goes without saying that it is also possible to provide
the spacer structure on the other side of the temperature control
mat, that is between the seat covering and the temperature control
mat. In this case, the effectiveness of the temperature control mat
is greatly reduced, however, because of the distance from the seat
covering, and the through-openings in the temperature control mat
are no longer important for allowing perspiration moisture through
the temperature control mat. Rather, the openings can then be used
for directing an air stream from the rear side through the openings
of the temperature control mat into the spacer structure.
[0020] If such a temperature control mat combined with a spacer
structure is placed in a seat and/or backrest element between the
outer seat covering and the actual cushion material, the
temperature of the seat covering can be influenced very rapidly and
cooled down to body temperature within about 60 seconds. The
cooling down of a leather seat covering from about 85.degree. C. to
a comfortable body temperature of 37.degree. C. to 40.degree. C.
can be achieved for example in one minute. For this purpose, the
temperature control fluid flows through the fluid chambers of the
fluid chamber system until the desired seat surface temperature is
reached. Preferably used as the temperature control fluid is an
environmentally compatible liquid, for example water, possibly
mixed with an anti-freezing agent, such as glycol or salt solution
for example, and an anti-rotting agent and other additives. The use
of liquid offers the advantage over a gas of greater heat capacity
along with good heat transfer properties, whereby the temperature
control of the seat covering is particularly effective.
[0021] On account of this effectiveness, the seat covering can be
brought to the desired temperature in a very short time, even
before a person sits down on it. For example, the temperature
control can be switched on automatically when the vehicle is
unlocked. Activation by remote control or a timer circuit is
likewise possible. In particular, it is not necessary to start the
vehicle in order to make the power required for the temperature
control of the seat covering available. The temperature control
liquid does not necessarily have to be cooled down to cool the seat
covering, but may be pumped from a storage tank which is located at
a relatively cool place, for example in the region of the vehicle
floor, so that the temperature control liquid is at most at ambient
temperature. This storage tank preferably has an insulating casing.
The supply of liquid contained in it may be additionally cooled,
for example during driving or possibly also when the engine is
switched off, if the vehicle battery produces sufficient power. A
Peltier element comes into consideration for example as the cooling
element.
[0022] According to the same principle, the seat covering can be
heated up. For this purpose, a heated fluid, such as water for
example, flows through the fluid chamber system. In a preferred
embodiment, the fluid is heated by a heating element to a
temperature of approximately 40.degree. C. to 50.degree. C.
[0023] The temperature control fluid is pumped through the fluid
chamber system until the desired temperature is reached.
Subsequently, the fluid chambers of the fluid chamber system are
pumped empty. Since the fluid chamber system is formed by
interconnected films of plastic, the pumped-empty chambers collapse
and form a largely planar surface. To ensure complete emptying of
all regions of the fluid chamber system, it is advantageous to
integrate spacers, for example thin fibers, woven or non-woven
fabrics, into the fluid chamber system. When the fluid chamber
system has been emptied, the temperature control mat consequently
does not press through the seat covering, so that the original
sitting comfort properties are restored immediately after the
desired seat covering temperature is reached. The visual impression
of the surface is not adversely affected by the temperature control
mat. A person sitting on the seat does not feel the temperature
control mat at all.
[0024] If a person then sits down on the seat, brought to an
acceptable temperature in advance, this person will perspire to the
usual extent or--in the case of hot outside temperatures--possibly
also to an increased extent. In the case of conventional seats,
this often leads to clothing that is against the seat covering
becoming soaked by perspiration. In this connection, the openings
arranged in a distributed manner in the temperature control mat are
of great importance. This is so because these openings offer the
possibility of removing this perspiration moisture passively or
preferably actively. A precondition for this is firstly that the
moisture can pass through the seat covering. In the case of textile
coverings, this is readily ensured, since textile coverings act
like a wick for moisture. Standard leather car seat coverings are
not breathable, or scarcely so, i.e. they can at best only remove
minimal amounts of water vapor. However, now there are also
breathable leathers, which are adequately moisture-permeable
without perforation, and can therefore be used for seat coverings.
Instead of vapor-permeable leather coverings, it goes without
saying that perforated leather may also be used for the seat
covering.
[0025] Although the previously described temperature control mat is
intended essentially for the cooling of surfaces, it can also be
used for the heating of surfaces. The two functions can also be
combined. A preferred embodiment provides for this purpose a bypass
line in the fluid circuit, by which the cooling fluid reservoir is
bypassed. In the bypass line there is a heating element, preferably
a continuous flow heater, with which the temperature control fluid
is heated, in order by this means to heat the surface. It goes
without saying that the heating function of the temperature control
mat according to the invention may also be combined with
conventional heating elements, such as for example with an
electrical resistance heater in the seat and/or backrest element
and the like, merely to assist the latter.
[0026] The particular advantages achieved by the invention are to
be seen in that it provides a rapidly acting temperature control
system--in particular for rapid cooling/heating and efficient
moisture removal--which does not adversely affect the sitting
comfort or the appearance of the surface to be cooled, is effective
and is not felt to be uncomfortable by a person sitting on the
seat. In addition, the temperature control mat according to the
invention can be handled easily and can be integrated into a seat
and backrest element in a simple way.
[0027] A further advantage of the temperature control system
according to the invention with the temperature control mat
according to the invention is the resistance to the typical loads
to which a seat element of a car seat is subjected. Car seats are
subjected to sustained loads, which also have to be withstood by
the temperature control system integrated into the seat.
Conventional pipeline and hoseline temperature control systems can
in this case be displaced and mechanically damaged considerably
over time unless they are integrated into the seat element in a
complex way. By comparison with this, the temperature control mat
according to the invention can be securely connected in a simple
way to the seat covering or the cushion core by adhesive bonding
and/or sewing. But even without such fixing, the temperature
control mat according to the invention is not displaced, because of
its extent over a large area under the seat covering. This does not
occur in particular if the temperature control mat is securely
combined with a spacer structure. The high resistance of the
temperature control mat according to the invention is also
additionally based on the very smooth surface of the films of
plastic of the temperature control mat--in particular in the case
of fluoropolymers--which on account of this very property does not
rub against the seat covering, so that no frictional wear occurs.
Finally, it should also be mentioned that the layers of plastic
forming the fluid chamber system may have additional reinforcing
layers, for example in the form of a nylon woven fabric.
[0028] The aforementioned advantages can be optimized by suitable
choice of the layers of plastic forming the fluid chamber
system.
[0029] To be able to produce the temperature control mat in a
simple way, the layers of plastic should be capable of being
welded, laminated, coextruded, sintered or blow-molded with one
another. In principle, the following materials are suitable for
example: thermoplastic polyurethane (TPU), thermoplastic polyester
(TPE), polyamide (PA), polytetrafluoroethylene (PTFE), expanded
polytetrafluoroethylene (ePTFE), polyvinylidine fluoride (PVDF),
ethylene/tetrafluoroethylene copolymer (ETFE), fluorinated ethylene
propylene (FEP) and other fluoropolymers. These materials are
preferably fiber- or fabric-reinforced.
[0030] Of these materials, TPU is suitable to a particular extent
because of its flexibility along with good affinity for adhesive
bonding with other materials, in particular with leather.
Fluoropolymers are suitable because of their diffusion
impermeability and good sliding properties, and accompanying
resistance to wear, but are less well able to bond adhesively with
seat covering materials. Fluoropolymers are additionally highly
temperature-resistant and are therefore particularly suitable in
combination with a heating element integrated into the cushion.
Such heating elements may be up to 120.degree. C. hot. A
particularly temperature-resistant fluoropolymer is, for example,
PTFE. Finally, fluoropolymers are distinguished by high chemical
resistance, which is significant when additives are used in the
temperature control fluid.
[0031] In addition, the layers of plastic from which the fluid
chamber system is formed should be as thin and flexible as
possible, in order that the fluid chamber system can be emptied
without difficulties and thereby collapses without any major folds,
so that the deactivated temperature control mat cannot be felt or
seen through the cushion covering. The layers of plastic may, for
example, respectively have a thickness in the range from 10 .mu.m
to 1 mm, good results having been achieved for example with a layer
thickness of 200 .mu.m in each case.
[0032] For a low-maintenance system, it is advantageous to operate
the fluid circuit in the fluid chamber system as a closed system.
In this case, great value should be attached to the diffusion
impermeability of the films of plastic used, in order that fluid
losses over the service life are kept low.
[0033] However, the variant of a partly open system is also
possible. In this case, the emptying and complete filling of the
fluid chamber system is additionally assisted by at least one of
the layers of plastic forming the fluid chamber system being
liquid-impermeable but air-permeable, at least in certain regions,
so that an exchange of air can take place through the fluid-chamber
wall, in particular the venting of undesired inclusions of air.
Particularly suitable in this connection is expanded
polytetrafluoroethylene (ePTFE) with a low porosity, to keep the
evaporation losses low during operation. Tests with a low porosity
of, for example, 2% to 30% (measured with a Capillary Flow
Porometer CFP-1500-AXLS from PMI--Porous Materials, USA) and a high
water ingress pressure of over 6 bar have produced good
results.
[0034] The openings in the temperature control mat which serve for
moisture removal may comprise 20% to 80% of the projected surface
area of each of the layers of plastic forming the fluid chamber
system. Good results have been obtained for example with an opening
surface area accounting for 30% to 40% of the projected total
surface area. The contour of the openings may be chosen as desired.
In particular, they do not have to be circular and may be of
different sizes. The openings should offer the least possible
diffusion resistance and therefore in any event be macroscopic, in
order not to hinder the moisture removal through the openings. An
average opening diameter may for example lie in the range from 1 mm
to 30 mm. Good results have been obtained for example with an
average opening diameter of approximately 5 mm. On account of the
thin wall thickness of the fluid chamber system and the large
openings passing through the fluid chamber system, a low diffusion
resistance is achieved for the water vapor passing through the
openings. Moisture-laden air can pass relatively unhindered through
the openings into the spacer structure and is transported away by
the air flowing through the spacer structure.
[0035] Just as the openings may have any desired contour, size and
arrangement within the temperature control mat, the chambers of the
fluid chamber system may also have extremely different forms. It
goes without saying that a uniform arrangement of the fluid
chambers is to be preferred for the purpose of uniform temperature
control of the seat covering. There is in this case the possibility
of realizing one or more fluid chamber systems in a temperature
control mat, it being possible in turn for each fluid chamber
system to have one or more fluid inlets and/or fluid outlets. One
or more common fluid inlets and outlets may be provided, but fluid
inlets and outlets that are independent from one another are to be
preferred, to permit a continuous flow through the fluid chambers.
It is particularly advantageous if precisely one fluid inlet and
one fluid outlet are respectively provided for a seat element and a
rest element and if the respective fluid chamber systems have
numerous fluid chambers in fluid connection with one another, so
that the temperature control fluid flows on one side into the fluid
chamber system and flows through the numerous fluid chambers partly
in parallel and partly in succession, in order subsequently to flow
out again from the fluid outlet.
[0036] Such a structure is on the one hand uncomplicated in its
production and integration into a circuit system. On the other
hand, the flow paths are short, so that the flow resistance is low
and the heat transfer over the entire length of flow is virtually
uniform. The fluid passages formed between fluid chambers in
connection with one another should have a length in the range from
3 mm to 50 mm, in order to achieve optimum mixing of the fluid.
[0037] An effective heat transfer is assisted furthermore by the
fact that the temperature control mat, in the state in which
temperature control fluid is flowing through it, swells slightly
and presses against the seat covering. The total thickness of the
filled temperature control mat ranges between approximately 0.5 mm
and 10 mm.
[0038] The invention is explained below by way of example on the
basis of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1a shows a car seat with integrated temperature control
mats schematically in cross section.
[0040] FIG. 1b shows the arrangement of the temperature control
mats according to FIG. 1 in the car seat in plan view.
[0041] FIG. 2 shows the detail A from FIG. 1 during a cooling or
heating phase.
[0042] FIG. 3 shows the same detail as FIG. 2 after a completed
cooling or heating phase, during the moisture removal phase.
[0043] FIG. 4 shows the detail from FIG. 3 in realistic relative
sizes.
[0044] FIG. 5 shows a first exemplary embodiment of a temperature
control mat in plan view.
[0045] FIG. 6 shows a second exemplary embodiment of a temperature
control mat in plan view.
[0046] FIG. 7 shows a third exemplary embodiment of a temperature
control mat in plan view.
[0047] FIG. 8 shows a schematic representation of a temperature
control circuit.
DETAILED DESCRIPTION OF THE INVENTION
[0048] FIG. 1a shows a car seat 1 comprising a seat element 2 and a
backrest element 3. Located under the seat coverings 4 both of the
seat element 2 and of the backrest element 3 there is in each case
a temperature control mat 5, which is kept at a distance from the
cushion core 7 by a spacer structure 6. Water (H.sub.2O) is pumped
as a temperature control fluid by means of a pump P from a storage
tank 9 through the temperature control mat 5 through a system of
fluid lines 8, which is represented as dashed lines with thin,
black arrows, in order to control the temperature of (temperature
control phase), in particular to cool (cooling phase), the seat
covering 4 from the rear side. After completion of the temperature
control phase, air is made to flow through the spacer structure 6
by means of a fan (white arrows), in order to assist the
dissipation of perspiration moisture passing through the seat
covering 4.
[0049] FIG. 1b shows the arrangement of the temperature control mat
5 in the car seat 1 according to FIG. 1 in plan view.
[0050] The cooling phase (or heating phase) is schematically
represented in cross section in FIG. 2 in somewhat more detail. The
temperature control mat 5 comprises regularly arranged,
interconnected fluid chambers 10, the individual fluid chambers
being spaced apart from one another by openings 11 penetrating
through the temperature control mat 5. When the fluid chamber
system formed by fluid chambers 10 is filled with the cooling
liquid, the fluid chambers 10 expand to a thickness which should
lie between 0.5 and 10 mm, and come to bear closely against the
rear side of the seat covering 4. As a result, a particularly
effective heat transfer is achieved between the temperature control
fluid in the fluid chambers 10 and the seat covering 4. The flow
through the fluid chamber system may take place intermittently or
continuously. The structure of the fluid chamber system presses
slightly through the seat covering 4 in this temperature control
phase.
[0051] When a desired seat covering temperature has been reached, a
shut-off valve, not represented in FIG. 1, in the supply line of
the system of fluid lines 8 to the temperature control mat 5 is
closed and all the temperature control fluid remaining in the
temperature control mats 5 is pumped back into the storage tank 9.
When this happens, the fluid chambers 10 collapse, so that the
temperature control mat 5 also collapses. This is schematically
represented in somewhat more detail in FIG. 3. On account of the
thin and flexible films of plastic from which the fluid chamber
system is formed, the temperature control mat 5 in the collapsed
state no longer presses through the seat covering 4. Any minor
folds are not significantly noticeable.
[0052] If a person sits down on the temperature-controlled seat
after the cooling phase, the second temperature control phase
begins, aimed at removing moisture perspired by the person through
the seat covering 4 and the openings 11 of the temperature control
mat 5. For this purpose, the spacer structure 6 is provided between
the cushion core 7 and the temperature control mat 5. Any open
structure which on the one hand is flexible, in order to make the
seat comfortable to sit on, but on the other hand cannot be
completely compressed under exposure to pressure, so that
ventilation through the spacer structure 6 remains ensured under
any circumstances, comes into consideration as the spacer structure
6. Suitable for example are nonwoven or knitted polymer-fiber
fabrics. The dissipation of the moisture transported through the
seat covering 4 is assisted by an actively produced air stream in
the spacer structure 6, which is indicated in FIG. 3 by arrows.
[0053] The detail represented in FIG. 3 is reproduced once again in
FIG. 4, enlarged with the individual layers in realistic
proportions. The seat covering 4 has, for example, a thickness of
1.2 mm and is water-vapor-permeable. Breathable leather,
micro-perforated leather, microfibers such as Alcantara or a woven
textile covering may be used as the material for the seat covering.
The seat covering should preferably have a Ret value of 5 to 20
m.sup.2Pa/W. The Ret value, as a specific material property of
textile fabrics and other textile material structures, defines
their water-vapor transmission resistance. In this case, the latent
evaporation heat flux through a given area in consequence of an
existing steady-state partial pressure is determined. The Ret value
is ascertained by means of the Hohenstein skin model test, which is
described in the standard test specification Ne. BPI 1.4 of
September 1987 of the Bekleidungsphysiologisches Institut e.V.
Hohenstein.
[0054] If it is a leather covering, its outer side is usually
largely sealed by a protective layer 12. The moisture permeability
of a leather seat covering 4 therefore depends essentially on the
water-vapor transporting properties of the protective layer 12. For
the purposes of the present invention, the leather covering should
preferably have an MVTR value (according to DIN 53 333) of greater
than 10 mg/cm.sup.2h. Breathable leathers with an MVTR value of
more than 12 mg/cm.sup.2h are particularly preferred. Such leathers
are obtainable for example from the Vogl leather factory in
Mattinghofen/Austria. In the case of a non-breathable, in
particular fully sealed leather covering, a micro-perforation of
the covering also comes into consideration. This is to be
understood as meaning a leather with pores usually produced in a
needling process, with a pore diameter of 80 .mu.m to 100 .mu.m.
Microperforated leathers with a thickness of between 1.9 mm and 2.5
mm achieve an MVTR value of between 2 and 6 mg/cm.sup.2h, which may
be adequate for the purposes of the invention.
[0055] The perspired moisture then diffuses through the permeable
seat covering 4 to the temperature control mat 5 and through the
openings 11 of the temperature control mat 5 into the spacer
structure 6 lying thereunder. The temperature control mat 5
essentially comprises two thin films of plastic 5a, 5b, lying one
on top of the other and connected to each other in a suitable way.
In the emptied state, the temperature control mat 5 has a slightly
rough surface due to fold formations of the thin films of plastic
5a, 5b. As a result, moisture can also reach an opening 11 of the
temperature control mat 5 from those points of the seat covering 4
under which an opening 11 is not directly located.
[0056] On account of the two thin films 5a, 5b with a thickness of
for example 200 .mu.m in each case, the path through the openings
11 is very short. In one embodiment, the filled temperature control
mat 5 has a thickness of 4 mm. In particular, no build-up of
moisture forms in the openings 11 and no boundary layer forms
between the air in the openings 11 and the air flowing through the
spacer structure 6, so that the moisture diffused through the seat
covering 4 is reliably entrained by the air stream in the spacer
structure 6. For the same reason, the opening diameters of the
openings 1 are chosen to be comparatively large and, in the
exemplary embodiment represented, are approximately 3.5 mm.
[0057] The spacer structure 6 has, for its part, a thickness of
approximately 6 mm to 10 mm in the exemplary embodiment
represented. Depending on the material used for the spacer
structure 6, it may be meaningful to make the spacer structure 6
thicker or thinner.
[0058] With its rear side, the spacer structure 6 is adjacent to
the cushion core 7, which is for example a closed-cell foam core.
The air stream directed through the spacer structure 6 (arrow) is
therefore guided essentially parallel to the covering between the
temperature control mat 5 and the closed-cell cushion core 7.
[0059] The spacer structure 6 and the temperature control mat 5 may
be adhesively bonded to each other, whereby the entire arrangement
can be easily handled and can be correspondingly easily integrated
into a car seat. If the temperature control mat 5 is not adhesively
bonded to the spacer 6, it is essential that the spacer structure 6
has a non-abrasive surface, since otherwise damage to the thin
films of plastic 5a, 5b of the temperature control mat 5 would have
to be feared in the long term.
[0060] The temperature control mat 5 is preferably connected,
preferably adhesively bonded, to the seat covering 4--with or
without spacer structure 6. As a result, rubbing between the seat
covering 4 and the temperature control mat 5 is avoided, whereby
the service life of the temperature control mat 5 is
correspondingly increased.
[0061] The necessary air throughput through the spacer structure 6
for removing moisture from the seat covering 4 is extremely low,
since only little moisture is removed through the seat covering.
Therefore, it is adequate if air is blown from the passenger
compartment of the vehicle through the spacer structure 6 in an
uncomplicated way by means of a simple fan with a power of, for
example, 0.3 to 3 W. In one embodiment, the spacer structure 6 is
connected directly or indirectly to the vehicle's ventilation
system or air-conditioning system.
[0062] In FIG. 5, a first exemplary embodiment of a temperature
control mat 5 is represented in plan view. The temperature control
mat 5 comprises two films which are welded or laminated to each
other and penetrated by regularly distributed openings 11. As a
result, a fluid chamber system comprising numerous fluid chambers
10 in connection with one another is formed. The two interconnected
films 5a, 5b may also be produced by a blow-molded and laid-flat
film bubble or by coextrusion, the openings 11 being cut out from
the film stack in a subsequent method step with simultaneous
welding of the films.
[0063] Water (H.sub.2O) as the temperature control fluid is
directed into the fluid chamber system via a fluid inlet 13 and out
again through a fluid outlet 14. The temperature control fluid
H.sub.2O is thereby distributed uniformly in the fluid chamber
system and--by contrast with a meandering system of lines--passes
from the fluid inlet 13 to the fluid outlet 14 over a relatively
short path. However, as a departure from the exemplary embodiment
represented in FIG. 5, the fluid chamber system may also have one
or more line-like fluid chambers, which are arranged in a parallel
or meandering manner. A number of fluid inlets and/or fluid outlets
may also be provided. However, the exemplary embodiment according
to 5 is particularly efficient, can be easily produced and can be
integrated with little effort into the seat because of the only two
inlets and outlets.
[0064] FIG. 6 shows a second exemplary embodiment of a temperature
control mat 5 likewise schematically in plan view. In this case,
the openings 11 are arranged offset in relation to one another,
whereby they are packed more closely and the removal of moisture
through the openings is correspondingly more effective.
[0065] FIG. 7 shows a third exemplary embodiment of a temperature
control mat 5 likewise schematically in plan view. In this case,
two fluid inlets 13 and two fluid outlets 14 are provided. Fluid
can flow via a fluid-inlet distributing chamber 13a and a
fluid-outlet collecting chamber 14a simultaneously into one and
from a plurality of fluid chambers 10 adjacent thereto, which for
their part are arranged partly in parallel and partly one behind
the other in the direction of flow. The fluid chambers 10 define
fluid passages of any desired length, which should preferably have
a length of approximately 50 mm or less. Between the fluid chambers
10, the films forming the temperature control mat 5 are welded to
each other. Provided in these welded regions are the openings 11,
through which the moisture removal takes place. The temperature
control mat 5 is in this case fixed on the seat cushion, not
represented here, by means of seams 22. However, adhesive bonding
is to be preferred, since it does not show in the seat
covering.
[0066] FIG. 8 schematically shows a suitable temperature control
system. Water H.sub.2O is pumped by means of a pump P from the
storage tank 9 through the temperature control mat 5 and back into
the storage tank 9. The volume of temperature control fluid in the
overall system may lie, for example, in the range from 500 ml to
1500 ml, the storage tank 9 holding for example 800 ml or 1000 ml
and the temperature control mat 5 holding between 50 ml and 250 ml,
for example 200 ml. The operating pressure of the pump P lies in
the range between 0.2 and 2 bar, for example approximately 0.5 bar.
The pump running time preferably lies between 10 seconds and 120
seconds, but as far as possible should not exceed 90 seconds. The
power necessary for this can be comfortably provided by the
vehicle's own battery. Even if the temperature control fluid in the
storage tank 9 is at ambient temperature of 32.degree. C. to
40.degree. C., it is possible with this system for a leather seat
covering for example to be brought to a desired temperature of
approximately 37.degree. C. to 44.degree. C. in a maximum of 90
seconds. Cooling by 40 K within less than 60 seconds is achievable.
If the seat covering temperature is lowered to 35.degree. C., for
example, the temperature control mat 5 is pumped empty and the pump
P is stopped. It goes without saying that higher operating
pressures are also possible, provided that the fluid chamber system
is designed for higher pressures. Operating pressures of 1.5 to 2
bar are currently realistically achievable. For safety reasons, the
temperature control mat should withstand operating pressures of up
to approximately 3 bar. The higher the operating pressure, the
harder the temperature control mat 5 presses against the seat
covering and the more effective the heat transfer and consequently
the temperature control of the seat covering. Consequently, the
heat transfer can be controlled by the system pressure.
[0067] The temperature in the storage tank 9 can be monitored by
means of a temperature sensor and if need be cooled down by a
suitable cooling device. A Peltier element is suitable for example
as the cooling device 15. In addition, the storage tank 9 is
encased with an insulation 16, in order to prevent heat exchange
with the warmer surroundings.
[0068] Once the desired seat covering temperature has been reached,
the valve 17 in the supply line of the system of fluid lines 8 is
blocked and the temperature control mat 5 is pumped empty. In the
subsequent moisture removal phase during driving, air is directed
past the spacing structure 6, not represented in FIG. 6, on the
temperature control mat 5, as described above, by means of a simple
fan.
[0069] A special development provides a bypass 18, with which the
cooling fluid storage tank 9 is bypassed. By appropriate switching
of the shut-off valve and a further shut-off valve 19, which are
accordingly formed as multi-way valves, the fluid present in the
temperature control system can be directed through the bypass 18
and heated by means of a heating element 20 arranged therein, for
example a continuous flow heater. As a result, the temperature
control system may serve both as seat heating and as seat cooling.
On account of the operating pressure, the temperature control mat 5
in turn presses against the seat covering 4, whereby an efficient
heat transfer is ensured. This heat transfer is additionally
assisted by the weight of the person sitting on the seat. The
heating element can be regulated by a temperature sensor 21
arranged in the discharge line of the system of fluid lines 8.
Further temperature sensors 21 are provided in the temperature
control mat or directly on the seat covering and in the cooling
liquid storage tank 9. All the temperature sensors 21 are connected
to a control system, not represented, in which the measured
temperature values are processed and the individual components of
the temperature control system are correspondingly controlled.
Test Result
[0070] With the system described above it was possible to lower the
surface of a leather seat covering from a starting temperature of
85.degree. C. to a temperature of 44.degree. C. within less than 1
minute, the temperature control liquid comprising a temperature of
40.degree. C. and the system an overall volume of 800 ml.
* * * * *