The present disclosure is related to vehicle seating systems. More particularly, the present disclosure is related to thermal management and occupant positional sensing in vehicle seating.
The ability to regulate temperature within a vehicle is a desirable aspect for vehicle consumers. Vehicle HVAC systems have been in common use for years, allowing the vehicle occupants to increase/decrease the heating and cooling systems within the vehicle to obtain a desirable temperature. Various advances in vehicle heating and cooling have provided further ability to tailor the temperature within the vehicle to suit the needs of individual users.
One aspect of vehicle heating and cooling includes the use of seat heating devices and/or seat cooling devices. Rather than cooling the occupant via forced air from a vent in the vehicle interior, heating and cooling may be applied via contact with the user's body between the body and the vehicle seat.
In a seat heating device, current may be passed through conductive circuits, for example a circuit of nichrome wire. As the current passes through the wire, the resistance in the wire causes the wire to increase in temperature. The increase in temperature may be transferred to the vehicle occupant, who is seated on the vehicle seat adjacent the heating circuit.
In a seat cooling device, a fan may be used to transfer cool air from a cooling mat through apertures formed in the vehicle seat trim, thereby providing cool air to the occupant's body.
Additionally, seat surface temperatures, particularly in hot environments, can be unsafe. The existing cooling solutions utilizing fans can mitigate these surface temperatures, but they also create undesirable amounts of noise, which affects the comfort of the occupants.
Another related aspect of vehicle seat heating and cooling systems is an occupant positional sensing device. Occupant positional sensing devices may be used to determine whether a vehicle occupant is present, in particular for vehicle passengers. Such sensors may be used to trigger whether a passenger side airbag will deploy in case of an accident, or whether or not a fasten seatbelt signal will be emitted if the passenger seatbelt is not buckled. Similarly, the occupant sensor may be used to determine whether to apply seat heating or cooling to the passenger seats. For instance, if no passenger is detected, the heating or cooling circuits may be deactivated.
With these sensors serving different functions, these integrated seat devices are installed as separate devices, which adds complexity and cost to the vehicle, including additional assembly time. These systems have not been combinable because of the different types of technology used for heating (resistive heating) and cooling (convective cooling).
In view of the above, it is desirable for a more compact, simple, and cost-effective solution for regulating vehicle temperature.
It is an aspect of the present disclosure to provide heating, cooling, and occupant sensing to a vehicle seat in a single unit.
In one aspect, a vehicle seat system includes: a seat structure including leg portion and a back portion; a carbon nanotube (CNT) element attached to at least one of the leg portion and the back portion; a Peltier element attached to the carbon nanotube element; a heatbank attached to the Peltier element; a power supply electrically connected to the Peltier element, wherein the power supply is configured to apply a current to the Peltier element and the CNT element; wherein the Peltier element transfers heat between the CNT element and the heatbank in response to applying the current.
In one aspect, the CNT element is adapted to provide resistive heating and bypass the Peltier element
In one aspect, the CNT element is adapted to sense a presence of an occupant in the vehicle seat by deforming in response to the presented of a vehicle occupant to alter the current and/or resistance in the CNT element.
In one aspect, the heatbank is a seat rail of the seat structure.
In one aspect, the heatbank is a heatsink including a plurality of fins.
In one aspect, current passing in a first direction causes heat transfer from the CNT element to the heatbank via the Peltier element, and current passing in a second direction opposite the first direction causes heat transfer from the heatbank to the CNT element via the Peltier element.
In one aspect, the Peltier element is a first Peltier element and the system includes a second Peltier element, wherein the first and second Peltier element are operatively connected to separate CNT elements configured to heat and cool separate portions of the vehicle seat.
In one aspect, the heatbank has the first and the second Peltier elements mounted at opposite ends thereof
In one aspect, the CNT element is a mat.
In one aspect, the CNT element is woven into a seat cover.
In another aspect, a method of thermally managing a vehicle seat is provided. The method includes: providing a carbon nanotube (CNT) element at a vehicle seat; providing a Peltier element attached to the CNT element; providing a heat bank attached to the Peltier element; applying a current to the Peltier element in a first direction, and in response thereto transferring heat from the CNT element to the heat bank and cooling the CNT element; applying a current to the Peltier element in a second direction opposite the first direction, and in response thereto transferring heat to the CNT element and heating the CNT element.
In another aspect of the invention, CNT can be used as a resistive heating circuit directly, bypassing Peltier element, in addition to or alternatively to using the Peltier element to provide heat via the CNT element.
In one aspect, the method includes detecting a vehicle occupant via the CNT element by detecting a change in current and/or resistance in the CNT element.
In one aspect, the heat bank is in the form of a heat sink.
In one aspect, the Peltier elements are attached to seat rails, and the heat bank is in the form of the seat rails.
In one aspect, the CNT element is woven into a seat cover of the vehicle seat.
In one aspect, the CNT element is a mat disposed between a seat cover and a seat cushion of the vehicle seat.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring now to the Figures, a system 100 for providing thermal management and occupant position sensing is provided. The system 100 may include a seat assembly 102 and a controller 104, illustrated in
As shown in
As shown, the seat structure 106 may include a leg support portion 110 and a back support portion 112. The leg support portion 110 may be the portion that is generally horizontal to the vehicle floor. The back support portion 112 extends upwardly from the rear of the leg support portion 110. The back support portion 112 may be adjustable in a pivotable manner relative to the leg support portion 110.
With reference to the exploded view of
For reference,
Returning again to the present disclosure, the thermal structure 108 may be installed with the seat structure 106 in different ways, as further described below. In one aspect, the thermal structure 108 may include a mat portion 116 (
In one aspect, the thermal structure 108 includes a plurality of Carbon Nano Tubes (CNT) in the form of a CNT strand 120 (
As shown in
With reference to
As shown in the windowed portion of
As described above, in one aspect, the strand 120 may be woven into the material of the cover 110b. The strand 120 may be woven in a pattern that defines a path that crosses back and forth to span an area of the cover 110b for providing heating or cooling to the spanned area, such as that shown in
In one aspect, and with reference to
Along with the use of Peltier elements 134, the thermal circuit 132 may also include a heat bank 136, as shown in
In one aspect, shown in
In one aspect, the TiM 138 is a compressible material with high conductivity. In one aspect, the TiM 138 may be a solder, a Room Temperature or Near Room Temperature liquid metal alloy, a thermally conductive adhesive such as an epoxy filled with super-fine particles, thermal greases and compounds, phase change materials, thermal sheets, pads, foils, and the like. Thermal adhesives and solders may provide an added benefit of providing a mechanical attachment between the heat bank 136 and the Peltier element 134. Other thermal interface materials may also be used for improving the heat transfer between the Peltier elements 134 and heat bank 136.
With the TiM 138 disposed between the heat bank 136 and the Peltier element 134, heat may be transferred between the CNT element 130 and the heat bank 136 via the Peltier element 134 and the TiM 138, with the TiM 138 improving the efficiency of the heat transfer.
In one aspect, the Peltier element 134 may be attached to a power supply (or the like) capable of generating a DC current, with the Peltier element 134 including a pair of leads for connecting to the power supply. One side (which may be in the form of a plate) of the Peltier element 134 is attached to a first lead, and the other side (which may also be in the form of a plate) of the Peltier element 134 is attached to a second lead. Current can therefore pass through the Peltier element 134 via these leads connected to the power supply. The direction of current passing through the leads may be controlled by the power supply. For example, current may pass from the first lead to the second lead (a first direction) or current may pass from the second lead to the first lead (a second direction that is opposite the first direction. The direction of current passing between the two leads (as set by the power supply) determines the direction of the heat transfer. In a first direction, with heat flowing from the CNT element 130 to the heat bank 136, the CNT element 130 will be cooled. In a second direction, with heat flowing from the heat bank 136 to the CNT element 130, the CNT element 130 will be heated.
Accordingly, the use of the Peltier element 134 (and its associated leads and power supply) allows the CNT element 130 to be selectively heated or cooled, thereby providing both a heating function and a cooling function from the same element/material. This ability to both heat and cool is an improvement on the separate prior art structures that were limited to only one of either heating or cooling.
In one aspect, the heat bank 136 may be in the form of a heat sink 150 having a plurality of fins 150a, as shown in
Accordingly, when the CNT element 130 is hot, for example inside a hot vehicle, the Peltier element 134 may be actuated to transfer heat from the CNT element 130 to the heat sink 150, and heat may be dissipated from the heat sink 150 via the fins 150a. The heat sink 150 may be a separate component attached to the vehicle structure (such as the floor of the vehicle cabin), or it may be attached to the vehicle seat structure 106.
In another aspect, shown in
In one aspect, the seat rails 114 may include fins similar to the heat sink 150 described above. In another aspect, one Peltier element 134 may be mounted to a seat rail 114 and another Peltier element may be mounted to a separate heat sink 150. It will be appreciated that multiple Peltier elements 134 may be used and mounted to multiple types of heat banks 136 (heat sink 150 or seat rail 114).
In one aspect, two Peltier elements 134 may be used, with one Peltier element 134 mounted to one of the seat rails 114, and another Peltier element 134 mounted to the other seat rail 114. Each of the two Peltier elements 134 may be connected to CNT elements 130. By using two Peltier elements 134 mounted to different seat rails 114, the efficiency of the system may be improved. For example, the area of the seat to be heated or cooled may be divided among the Peltier elements 134, such that each Peltier element 134 is responsible for a smaller overall area to be managed thermally. Additionally, the overall area of the heat bank 136 is increased by using both seat rails 114. In one aspect, additional Peltier elements 134 may be provided to further divide the overall heating/cooling circuit. The use of additional Peltier elements 134 may also provide additional control to heat specific portions or locations of the overall seat structure.
In one aspect, the Peltier element 134 may be connected to CNT elements 130 disposed on both the leg portion 110 and the back portion 112 of the seat. When two Peltier elements 134 are used, each Peltier element 134 may be connected to CNT elements 130 disposed on both the leg portion 110 and the back portion 112. In another aspect, one of the two Peltier elements 134 may be connected to CNT elements 130 disposed on the leg portion 110, and the other Peltier element 134 may be connected to CNT elements 130 disposed on the back portion 112.
In one aspect, one Peltier element 134 may be disposed at one end of the seat rail 114, and another Peltier element 134 may be disposed at the opposite end of the seat rail 114, further dividing and dispersing the heat being transferred. Similarly, Peltier elements 134 may be disposed and spaced apart along the heat sink 150 in multiple locations. It will be appreciated that additional Peltier elements 134 may be added to heat sinks 150 or seat rails 114 to further distribute the heat being transferred.
In addition to transferring heat to and from the seat, the CNT element 130 may also be configured to perform occupant detection. For example, the CNT element 130 may be electrically connected to the controller 104, and the controller 104 may receive and process data based on current passing through the CNT element 130 or electrical resistance change due to CNT element change in length caused by the weight of the occupant to determine whether an occupant is present in the vehicle seat. In response to receiving a detected current, resistance, or other data, the controller 104 may automatically determine that the seat is occupied. The same CNT elements 130 used for heating and cooling can be used in a manner similar to traditional occupant detection/sensing systems. In one aspect, the controller 104 may determine which CNT elements 130 from multiple CNT elements have a changed current/resistance and automatically determine which portions of the overall seat structure are occupied. In one aspect ,the controller 104 may determine that the seat is not occupied by a passenger even in response to current/resistance changing, based on other CNT elements 130 having an unchanged or substantially unchanged current/resistance. For example, if a heavy object is placed on the seat, only the leg portion of the seat and a lower portion of the back portion may apply weight and cause a current/change in resistance, and the controller 104 may determine that the seat is unoccupied based on the particular CNT elements 130 that are changed relative to the CNT elements 130 that are unchanged.
As described above, the CNT element 130 may be woven into the material of the seat cover 110b /112b, with the ends of the CNT element 130 being attached to the Peltier elements 134. In another aspect, the CNT element 130 may be stitched, as a separate element, to the existing woven material of the seat cover 110b /112b and into an overall assembled form. Accordingly, manufacturing and assembly may be improved, by reducing the number of separate components that are later assembled to define the overall seat. However, it will also be appreciated that the CNT element 130 may be part of a mat structure 116, with the mat structure 116 inserted/placed between the foam of the cushion and the cover of the seat, with the mat 116 having the CNT elements 130 disposed therein. Whether disposed in the mat 116 or attached to the seat cover 110b /112b (via weave or stitching), the CNT elements 130 are disposed adjacent the upper surface of the seat and therefore adjacent the occupant for cooling or heating the seating surface, as desired. This close proximity of CNT element 130 to the seat occupant reduces thermal impedance of the system and decreases heating/cooling ramp up time to the desired temperature.
The operation of transferring heat via the Peltier element 134 and the CNT element 130 is generally the same regardless of the whether the CNT element 130 is a strand woven/stitched to the cover or whether the CNT element 130 is a mat. In each case, current may applied to the CNT element 130 via the Peltier element 134 to transfer heat to/from the CNT element 130 depending on the direction of the current. Thus, regardless of CNT element type, in hot weather, the CNT element 130 may be controlled to transfer heat to the heat bank 136 and away from the occupant, and in cold weather the CNT element 130 may be controlled to increase heat and transfer heat to the occupant.
In addition to using the Peltier elements 134 and the CNT element 130 for heating and cooling described above, the CNT element 130 may be used for resistive heating, wherein a current passes through the CNT element 130 and bypasses the Peltier element 134. In this aspect, the CNT element 130 may heat the seat via resistive heating. The CNT element 130 may provide increased levels of resistive heating relative to Nichrome-based resistive heating.
Thus, in view of the above, heating, cooling, and occupant sensing may be accomplished using a single unit, rather than a separate unit for sensing, a separate unit for heating, and a separate unit for cooling. In one aspect, the CNT element 130 may be used for two of the three aspects, with a separate unit remaining for third aspect, or excluded from the system. For example, the CNT element 130 may be used for heating and cooling, and the occupant sensing may be excluded or managed via a separate element, depending on various design needs. In either case, system efficiency and assembly requirements are improved.
In one aspect, a method of using the system includes providing the CNT element 130 at the seat structure. The method further includes providing the Peltier element 134 attached to the CNT element 130. The method further includes providing the heat bank 136 attached to the Peltier element 130. In one aspect, the method includes applying a current to the Peltier element 134 and the CNT element 130 in a first direction, and in response thereto transferring heat from the CNT element 130 to the heat bank 136 and decreasing the temperature of the CNT element 130. The method may further include applying a current to the Peltier element 134 and the CNT element in a second direction opposite the first direction, and in response thereto increasing the heat of the CNT element 130. The method may also include bypassing the Peltier element and passing a current through the CNT element to provide resistive heating.
With reference to
Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims.
This PCT International Patent Application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/985,505 filed on Mar. 5, 2020, and titled “Seat Thermal Management And Positional Sensing”, the entire disclosure of which is hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US21/20808 | 3/4/2021 | WO |
Number | Date | Country | |
---|---|---|---|
62985505 | Mar 2020 | US |