Title:
Seat heating and cooling system
Kind Code:
A1


Abstract:
An apparatus for selectively heating and cooling (temperature conditioning) a seat on a vehicle, where the seat is exposed to the environment. A thermoelectric device selectively heats and cools a heat exchanger filled with a liquid. The heat exchanger includes, in one embodiment, an air trap chamber. The liquid is forced through a heat exchanger in the seat by a pump. The coil transfers heat by conduction through the seat to the seat's occupant. A controller permits selection of the amount of heating or cooling of the liquid. A switch determines the polarity of the voltage applied to the thermoelectric device, which determines whether the liquid is heated or cooled.



Inventors:
Mckenzie, Chris (Knoxville, TN, US)
Bates, Danny J. (Jefferson City, TN, US)
Application Number:
11/242155
Publication Date:
02/09/2006
Filing Date:
10/03/2005
Assignee:
Coolseat Technologies, Inc. (Knoxville, TN, US)
Primary Class:
International Classes:
F28D1/06; B60N2/02; B60N2/56; B62J1/00; B62J33/00; F28F3/12
View Patent Images:



Primary Examiner:
DUONG, THO V
Attorney, Agent or Firm:
PITTS & LAKE P C (KNOXVILLE, TN, US)
Claims:
Having thus described the aforementioned invention, we claim:

1. An apparatus for temperature conditioning a seat that is exposed to an environment, said apparatus comprising: a first heat exchanger coupled to a seat for providing heat exchange with an occupant of said seat, said first heat exchanger including a liquid tight bladder through which a first heat transfer fluid is circulated, said first heat transfer fluid being a liquid; a second heat exchanger in fluid communication with said first heat exchanger, said second heat exchanger including an air trap chamber; a first pump for forcing said first heat transfer fluid between said first heat exchanger and said second heat exchanger; a thermoelectric device having a first surface and a second surface, said first surface thermally coupled to said second heat exchanger; a third heat exchanger thermally coupled to said second surface of said thermoelectric device; a radiator in fluid communication with said third heat exchanger; a second pump for forcing a second heat transfer fluid between said third heat exchanger and said radiator, said second heat transfer fluid being a liquid; and a controller providing power to said thermoelectric device, said controller selectively heating one of said first and second surfaces, said controller selectively cooling the other of said first and second surfaces, said controller including a ramp circuit that applies power to said thermoelectric device over a specified period of time.

2. The apparatus of claim 1 further including a temperature selector, said temperature selector in communication with said controller, said controller varying a current flowing through said thermoelectric device.

3. The apparatus of claim 1 further including a switch for reversing a polarity of a direct current voltage applied to said thermoelectric device.

4. The apparatus of claim 1 wherein said first heat exchanger includes a bladder with at least one channel for directing said first heat transfer fluid through said bladder.

5. The apparatus of claim 1 further including a safety cutout device for stopping a direct current voltage applied to said thermoelectric device, said safety cutout device sensing a temperature and operating when said sensed temperature exceeds a selected temperature.

6. An apparatus for temperature conditioning a seat that is exposed to an environment, said apparatus comprising: a first heat exchanger coupled to a seat for providing heat exchange with an occupant of said seat; a second heat exchanger in fluid communication with said first heat exchanger, said second heat exchanger including an air trap chamber; a first pump for forcing a first heat transfer fluid between said first heat exchanger and said second heat exchanger, said first heat transfer fluid being a liquid; a thermoelectric device having a first surface and a second surface, said first surface thermally coupled to said second heat exchanger; a third heat exchanger thermally coupled to said second surface of said thermoelectric device; and a controller providing power to said thermoelectric device, said controller selectively heating one of said first and second surfaces, said controller selectively cooling the other of said first and second surfaces, said controller including a ramp circuit that applies power to said thermoelectric device over a specified period of time.

7. The apparatus of claim 6 further including a temperature selector, said temperature selector in communication with said controller, said controller varying a current flowing through said thermoelectric device.

8. The apparatus of claim 6 further including a switch for reversing a polarity of a direct current voltage applied to said thermoelectric device.

9. The apparatus of claim 6 further including a radiator in fluid communication with said third heat exchanger and a second pump for forcing a second heat transfer fluid between said third heat exchanger and said radiator.

10. The apparatus of claim 6 further including a heat sink on said third heat exchanger and a fan circulating air across said heat sink.

11. The apparatus of claim 6 wherein said first heat exchanger is a bladder with at least one channel for directing said first heat transfer fluid through said bladder.

12. The apparatus of claim 6 further including a safety cutout device for stopping a direct current voltage applied to said thermoelectric device, said safety cutout device sensing a temperature and operating when said sensed temperature exceeds a selected temperature.

13. The apparatus of claim 12 further including a thermistor for sensing said temperature.

14. An apparatus for temperature conditioning a seat that is exposed to an environment, said apparatus comprising: a means for changing a temperature of a liquid; a means for trapping air in said liquid; a pump for transferring said liquid to a seat; and a means for conducting thermal energy between said liquid and said seat for heat transfer between said seat and an occupant of said seat.

15. The apparatus of claim 14 further including a means for controlling a temperature of said liquid.

16. The apparatus of claim 14 further including a means for transferring thermal energy between said means for changing said temperature and the environment.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of prior application Ser. No. 10/763,612, filed Jan. 23, 2004.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention pertains to a system that selectively heats and cools a seat. More particularly, this invention pertains to a seat heating and cooling system in which the heat transfer fluid is a liquid and the seat is an exposed seat, such as found on a motorcycle, a tractor, or industrial equipment.

2. Description of the Related Art

Drivers and passengers of automobiles and trucks have access to air conditioning systems within the vehicle and, in many cases, have the luxury of heated and/or cooled seats. Temperature controlled seats provide increased comfort.

The prior art discloses several different design approaches to the problem of providing an inexpensive, effective and long lasting heated and/or cooled seat. One approach, disclosed in U.S. Pat. No. 2,722,266, entitled “Refrigerated Seat and/or Back Rest,” issued to Kersten on Nov. 1, 1955, is to circulate a refrigerant through a coil in the seat, where the refrigerant can expand and cool the seat and any occupant.

Another, similar approach is disclosed U.S. Pat. No. 6,254,179, entitled “Air Conditionable Vehicle Seat,” issued to Kortum, et al., on Jul. 3, 2001. The Kortum patent discloses using the heating and/or cooling system existing in a vehicle on the primary side of a heat exchanger to heat and/or cool water on the secondary side, which passes through coils embedded in the vehicle seat. An advantage of the system cited by Kortum is that the water passing through the seat is preferably pure and does not contain any harmful additives. Another cited advantage is the utilization of the heating and/or cooling system integrated in the vehicle.

Another approach to seat conditioning is evidenced by various patents that disclose forcing air through the seat surface, thereby heating or cooling the occupant by convection. An example of this approach is disclosed in U.S. Pat. No. 6,223,539, entitled “Thermoelectric Heat Exchanger,” issued to Bell on May 1, 2001, which discloses a fan with a thermoelectric device, a Peltier device, integrated in its annulus. The Peltier device selectively heats and cools the air that is being pushed through the fan and into a vehicle seat, where it is discharged through a permeable surface of the seat.

A similar approach is disclosed in U.S. Pat. No. 5,117,638, entitled “Selectively Cooled or Heated Seat Construction and Apparatus for Providing Temperature Conditioned Fluid and Method Therefor,” issued to Feher on Jun. 2, 1992, which discloses a seat in which convection of air is used to heat and cool the seat occupant. Air is the temperature transfer fluid for a main heat exchanger and a liquid, such as a glycol/water mixture, is the fluid for an auxiliary heat exchanger. The energy from the auxiliary heat exchanger, which is transmitted through the liquid, is used to condition the air from the main heat exchanger discharged from the seat back. This system has the advantage of further conditioning the air that is being discharged at a distance from the original heat source.

Another similar approach, is disclosed in U.S. Pat. No. 6,510,696, entitled “Thermoelectric Air-Condition Apparatus,” issued to Guttman, et al., on Jan. 28, 2003. This patent discloses a Peltier device as a source that selectively heats or cools air. The conditioned air is forced, not through the motorcycle seat, but through a bodysuit and a helmet, thereby supplying conditioned air around the upper body and head of the motorcyclist.

Motorcyclists and drivers of vehicles that do not have an enclosed cabin, such as tractors, forklifts, and boats, do not have access to a cabin with an air conditioning system. It is desirable to provide a heating and cooling source to operators of such equipment. This equipment must operate with the operator subject to wind and other environmental conditions.

BRIEF SUMMARY OF THE INVENTION

According to one embodiment of the present invention, a seat heating and cooling system is provided. A thermoelectric device selectively heats and cools a liquid that is pumped through a seat heat exchanger, coils in one embodiment, a bladder in another. The liquid exchanges heat through the seat by conduction. In one embodiment, the thermoelectric device heats a liquid in a heat exchanger. The liquid is pumped through a seat heat exchanger that is, in one embodiment, inside the seat, thereby warming the seat surface by conduction. In another embodiment, the thermoelectric device cools the liquid, which consequently cools the seat.

In one embodiment, the liquid is a glycol mixture with antifungal and antibacterial properties. The liquid has a freeze point less than the expected ambient temperature expected for its service. In one embodiment, the liquid has a freeze point less than zero degrees Fahrenheit. In one embodiment, the system includes a temperature controller that prevents overheating of the liquid, thereby ensuring that the seat occupant is never exposed to a harmful temperature.

In one embodiment, a heat sink is thermally coupled to the thermoelectric device. The heat sink has air forced through it by a fan. In another embodiment, a second heat exchanger is in fluid communication with a radiator and transfers heat to/from the thermoelectric devices at the opposite end of the devices from the seat loop.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:

FIG. 1 is a pictorial view of a seat heating and cooling system;

FIG. 2 is a top view of the main heat exchanger;

FIG. 3 is a cross-sectional view of the main heat exchanger;

FIG. 4 is an exploded view of the main heat exchanger;

FIG. 5 is a cross-sectional view of the main heat exchanger;

FIG. 6 is a perspective view of the main heat exchanger assembly;

FIG. 7 is a cross-sectional view of a portion of the seat;

FIG. 8 is a block diagram of the electrical connections for the system;

FIG. 9 is a schematic diagram of the electrical connections for one embodiment of the system;

FIG. 10 is a schematic diagram of the electrical connections for a system with temperature control;

FIG. 11 is a pictorial view of another embodiment of a seat heating and cooling system;

FIG. 12 is a top view of one embodiment of a seat cooler;

FIG. 13 is a cross-sectional view of the embodiment of a seat cooler of FIG. 12;

FIG. 14 is an exploded view of one embodiment of a heat exchanger;

FIG. 15 is a perspective view of one embodiment of a seat side reservoir;

FIG. 16 is a perspective view of one embodiment of a seat side channel plate;

FIG. 17 is a perspective view of one embodiment of a opposing side channel plate;

FIG. 18 is a perspective view of one embodiment of a heat sink plate; and

FIG. 19 is a block diagram of another embodiment of the system.

DETAILED DESCRIPTION OF THE INVENTION

A seat heating and cooling system is disclosed. The system provides temperature conditioning of the seat, that is, the temperature of the seat is selectively raised or lowered. The system is suitable for use on vehicles in which the operator is exposed to the environment or in which the operator is not in an air conditioned environment.

FIG. 1 pictorially illustrates one embodiment of the seat heating and cooling system 10 adapted for use on a motorcycle. A motorcycle seat 102 has a coil 104 through which a heat transfer liquid is circulated by a pump 106. The liquid is pumped into a heat exchanger 108, which is part of a heat exchanger assembly 110. The heat exchanger assembly 110 includes the heat exchanger 108, a pair of thermoelectric devices 112a and 112b attached to opposite sides of the heat exchanger 108, a pair of heat sinks 114a and 114b, and a pair of fans 116a and 116b. The inboard surface of the thermoelectric devices 112a and 112b are thermally coupled to the heat exchanger 108. The outboard surface of the thermoelectric devices 112a and 112b are thermally coupled to heat sinks 114a and 114b, through which air 118a and 118b is forced by fans 116a and 116b.

The coil 104, the pump 106, and the heat exchanger assembly 110 are interconnected with tubing 122, 128, and 132. In one embodiment, the pump 106 and the heat exchanger assembly 110 are remote to the seat 102, and the tubing 122 and 128 have sealing quick disconnects 124 and 126 that allow the coil 104 in the seat 102 to be isolated from the remainder of the system 10. In one embodiment, the inlet to the pump 106 has an air separator to trap any air within the system 10.

The thermoelectric devices 112a and 112b, in one embodiment, are Peltier devices, which are devices that selectively cool and heat opposing surfaces based on the polarity of a direct current voltage applied to the device. With the polarity of the voltage applied to the thermoelectric devices 112a and 112b such that the temperature of the heat exchanger 108 is higher than ambient, and the heat transfer liquid is heated. The heated liquid is forced through the coil 104 in the seat 102, thereby warming the body surface of the occupant by conduction. The cooled liquid is pumped from the seat 102, through the pump 106, and into the heat exchanger 108, where the cycle is repeated. Those skilled in the art will recognize that the pump 106 can be located on either side of the heat exchanger 108 without departing from the spirit and scope of the present invention.

By reversing the polarity, the temperature of the heat exchanger 108 is made lower than ambient, and the heat transfer liquid is cooled. The cooled liquid is forced through the coil 104 in the seat 102, thereby cooling the body surface of the occupant by conduction. The liquid warmed by the occupant is pumped from the seat 102, through the pump 106, and into the heat exchanger 108, where the cycle is repeated.

FIG. 2 illustrates the top view of the heat exchanger 108. The top of the heat exchanger 108 has an inlet port 202 and an outlet port 204. In the illustrated embodiment, the two ports 202 and 204 are the same size, that is, they have the same diameter. In another embodiment, the outlet port 204 has a larger diameter than the inlet port 202, thereby reducing the backpressure of the outlet port 204.

FIG. 3 is a cross-sectional view of the heat exchanger 108. The heat exchanger 108 includes a body 304 and an end piece 302. In one embodiment, the end piece 302 is welded to the body 304, thereby forming a liquid-tight seal between the body 304 and the end piece 302. In another embodiment, the end piece 302 is attached to the body 304 with an adhesive or epoxy compound, thereby forming a liquid-tight seal. Inside the heat exchanger 108 are a series of ribs 306a, 306b, 306c, 306d, and 306e. These ribs 306a, 306b, 306c, 306d, and 306e serve two purposes, the first being to increase the surface area of the heat exchanger 108 exposed to the liquid. The second is to secure the baffle plate 402, illustrated in FIG. 4. Those skilled in the art will recognize that the number and size of the ribs can vary without departing from the spirit and scope of the present invention.

The heat exchanger 108, in one embodiment, is fabricated of aluminum, which is corrosion-resistant to the heat transfer liquid. In another embodiment, the heat exchanger 108 is fabricated of a material having a high heat transfer coefficient in order to maximize the transfer of heat between the heat transfer liquid and the thermoelectric devices 112a and 112b.

FIG. 4 illustrates the heat exchanger 108 in an exploded view. The end piece 302 is a top plate that covers the opening in the body 304. The baffle plate 402 is positioned inside the body 304 and secured in place between ribs 306b, 306c, 406b, 406c between the inlet and outlet ports 202 and 204. The baffle plate 402 has an opening 404 at the end opposite the ports 202 and 204, thereby allowing the fluid to flow from the inlet port 202, along the ribs 306a and 406a, through the baffle plate opening 404, along the ribs 306d, 306e, 406d, 406e, and through the outlet port 204. In one embodiment, the baffle plate 402 is fabricated of the same material as the body 108. The purpose of the baffle plate 402 is to direct the flow of the liquid over the greatest possible surface area of the heat exchanger 108.

In another embodiment, the heat exchanger 108 is formed of two halves with the split in the portion of the heat exchanger 108 between the two thermoelectric devices 112a and 112b. In this embodiment, the heat exchanger 108 is formed from two metal slabs that have the ribs 306 machined in one slab and the ribs 406 machined in the other. The two halves are mated and the ports 202 and 204 are drilled through one end. The fastening means that clamps the thermoelectric devices 112a and 112b to the heat exchanger 108 also secures the two halves together. In another embodiment, sealing means, such as an adhesive or O-ring, are employed to ensure that the heat exchanger 108 is fluid tight.

FIG. 5 illustrates a top view of the heat exchanger body 304. The ribs, or fins, 306 and 406 have the function of increasing the surface area of the inside of the heat exchanger 108, thereby increasing the heat transfer between the outside surface of the heat exchanger 108 and the liquid inside the heat exchanger 108. The ribs, or fins, 306 and 406 also function to secure the baffle plate 402 in position inside the heat exchanger 108. In one embodiment, the number of ribs 306 and 406 is greater than the ten illustrated, and multiple baffle plates 402 are used with the openings 404 offset to direct the fluid flow over a greater inside surface area of the heat exchanger 108.

FIG. 6 illustrates the heat exchanger assembly 110. The seat side fluid loop heat exchanger 108 is sandwiched between two thermoelectric devices 112a and 112b. The opposite sides of each of the thermoelectric devices 112a and 112b are each thermally attached to another heat exchanger that includes a heat sink 114a and 114b. The heat sinks 114a and 114b are heated or cooled by fans 116a and 116b, which force air over the fins 602a and 602b of the heat sinks 114a and 114b. The fins 602a and 602b are made of a thins sheets of material with high thermal conductivity, and a fan blade 616 in each fan 116a and 116b forces ambient air to flow between and through the fins 602a and 602b.

In one embodiment, the thermoelectric devices 112a and 112b are Peltier devices that have one surface that increases in temperature and a second surface that decreases in temperature upon the application of a direct current voltage. The two surfaces of the thermoelectric devices 112a and 112b that are subject to temperature changes have a large surface area, and one surface is thermally bonded to the heat exchanger 108 and the other is thermally bonded to the heat sinks 114a and 114b. In one embodiment, fasteners are used to draw the two heat sinks 114a and 114b together, thereby ensuring both a mechanical and thermal connection between the heat sinks 114a and 114b, the thermoelectric devices 112a and 112b, and the heat exchanger 108. In one embodiment, the fasteners are four turnbuckles, each one located at each corner of the heat sinks 114a and 114b, and the turnbuckles do not pass through the thermoelectric devices 112a and 112b or the heat exchanger 108.

In one embodiment, the thermoelectric devices 112a and 112b have heat transfer surfaces that are approximately two inches square and the heat exchanger assembly 110 is approximately seven inches wide, measured from fan 116a to fan 616b. In one embodiment, the heat exchanger assembly 110 and the pump 106 are mounted at a location away from the seat and are enclosed in a housing that provides protection from the environment, but still allows air flow through the fans 116a and 116b and the heat sinks 114a and 114b. The housing, in one embodiment, is incorporated in a bag or other enclosure secured to a travel rack attached to the rear fender of a motorcycle.

In order to minimize the energy loss for the remote installation of the heat exchanger assembly 110, the tubing 122, 128, and 132 between the seat 102, the pump 106, and the heat exchanger assembly 110 is insulated. In one embodiment, the tubing 122, 128, and 132 is covered with an insulator that is flexible, but with low thermal conductivity, for example, a closed cell neoprene. The portions of the tubing 122 and 128 extending from the coil 104 pass through the seat, which includes a material with low thermal conductivity and serves as insulation. The quick disconnects 124 and 126 are located just outside the seat 102.

The portions of the heat exchanger 108 that are not attached to the thermoelectric devices 112a and 112b are insulated to minimize undesired energy transfer between the heat exchanger 108 and the environment. In one embodiment, the heat exchanger 108 insulation is a ceramic coating having low thermal conductivity. In another embodiment, the insulation is an insulator that has low thermal conductivity, for example, closed cell neoprene.

FIG. 7 illustrates a cross-section of a portion of the seat 102 and the coil 104. In one embodiment, the seat 102 has a foam layer 702 shaped to the desired contour of the seat 102. In the illustrated embodiment, the coil 104 includes tubing arranged in a series of strips 104a, 104b, 104c, and 104d that are imbedded in the foam layer 702. Above the strips 104a, 104b, 104c, and 104d is an upper layer 704 of a material. The upper layer 704 serves to provide a smooth surface for the seat occupant and also has a high thermal conductivity to allow heat conduction through the upper layer 704, for example muslin The foam layer 702 and the upper layer 704 are encased in a cover that is waterproof, for example, vinyl or plastic. The waterproof cover is useful for motorcycles and other vehicles that do not have an enclosed cabin to protect the seat from the environment, in particular, rain.

The primary means for heat transfer is conduction between the seat 102 and the seat's occupant. The coil 104 selectively heats and cools the seat 102 by heat transfer between the liquid in the coil 104 and the seat 102. With a heated seat 102, the heat is conducted from the seat 102 to the occupant, and with a cooled seat, the heat is conducted from the occupant to the seat 102. Because an unprotected seat, and its occupant, is exposed to the environment, which includes wind, whether induced by nature or the speed of the vehicle, convective heat transfer is inefficient and unsuitable. Convection is the transfer of heat by the absorption of heat by a fluid at one point followed by motion of the fluid and rejection of the heat at another point. The seat heaters that operate with convective heat transfer use air as the fluid that transfers heat between the heating/cooling source and the occupant. An exposed seat subject to wind tends to reduce the amount of air that flows between the heating/cooling source and the occupant.

The liquid used for the heat transfer fluid requires certain properties because of the environment the system 10 operates. An unprotected seat is exposed to the range of temperatures in which it is stored and operated. For example, a motorcycle stored outside or in an unheated enclosure in a northern state can be expected to reach sub-zero temperatures in the wintertime. A motorcycle stored outside in a southern state can reach a temperature of approximately 100 degrees Fahrenheit. A black seat 102 exposed to sunlight in the Southwest can reach temperatures well over 100 degrees Fahrenheit. Accordingly, the liquid used as a heat transfer fluid must be able to accommodate these temperature extremes.

In one embodiment, the heat transfer fluid is a glycol liquid with a freezing point less than zero degrees Fahrenheit and a boiling temperature above 150 degrees Fahrenheit. In another embodiment, the heat transfer fluid is an inflammable liquid. In still another embodiment, the heat transfer fluid includes an anti-bacterial agent to retard biological growth in the liquid. In yet another embodiment, the heat transfer fluid has a high thermal conductivity and thermal capacity.

The pump 106 must also be able to operate within the temperature constraints identified above. When the system 10 is first started, the heat transfer fluid is at a temperature within the range described above. Accordingly, in one embodiment, the pump 106 has internal mechanisms, including seals and valves, that are suitable for operation at temperatures below zero degrees Fahrenheit. In another embodiment, the pump 106 is insulated, for example, with a cover of closed cell neoprene.

FIG. 8 illustrates a block diagram of one embodiment of an electrical control system for the system 10. A power supply 802 is controlled with a power switch 806. When the circuit is energized through switch 806, the fan 808 and pump motor 810 operate. A polarity switch 812, operated by a hot/cold switch 814, controls the power to the thermoelectric device 816. The thermoelectric device 816 is connected to a safety cutout device 818, which is controlled by a temperature sensor 822, and to a temperature controller 824, which has an operator controlled temperature selector 826 and a temperature sensor 828, which provides feedback for the temperature controller 824. In one embodiment, the hot/cold switch 814 and the temperature selector 826 are located on an operator panel within easy reach of the occupant of the seat 102.

FIG. 9 is a simplified schematic diagram of one embodiment of the electrical control system for the system 10. The system 10 is powered by the vehicle battery 802 and protected by a fuse 904. In another embodiment, the battery 802 is an auxiliary battery in the vehicle. Power to the system 10 is controlled via switch 806. In one embodiment, the switch 806 is a relay operated via a remote operator switch. After power is applied to the system 10, the two fan motors 808a and 808b and the pump motor 810 are energized.

A pair of polarity relays 812a and 812b control the polarity of the power applied to the thermoelectric devices 816a and 816b. Temperature selection switch 814 operates the polarity relays 812a and 812b, which reverses the polarity applied to the thermoelectric devices 816a and 816b when the polarity relays 812a and 812b are energized. With the polarity switch 814 in one position, the heat transfer fluid is heated, with the polarity switch 814 in the other position, the heat transfer fluid is cooled.

Series connected to the thermoelectric devices 816a and 816b is a contact from a cutout relay 918, which interrupts the current through the thermoelectric devices 816a and 816b when the temperature exceeds specified limits. The cutout relay 918 is operated by a transistor 926 operating as a switch. In series with a bias resistor 920 is a thermistor 822. A second resistor 924 completes the voltage divider controlling the transistor 926. The thermistor 822 changes resistance based upon a sensed temperature, and as the thermistor 822 resistance changes the voltage applied to the base of transistor 926, which switches when the voltage reaches a specified level. This circuit performs the function of the safety cutout device 818 and temperature sensor 822 illustrated in FIG. 8. The illustrated embodiment provides for operating the cutout relay 918 when a single limit is reached. In one embodiment, the limit is an upper temperature limit and cuts out the thermoelectric devices 816a and 816b when the temperature exceeds an upper limit.

In one embodiment, the thermistor 822 is thermally coupled to the heat exchanger 108 and the upper limit is approximately 120 degrees Fahrenheit, which is high enough to allow heating of the seat 102 and occupant, but not so high as to cause burning or bodily harm to the occupant. In another embodiment, the thermistor 822 is monitoring the heat transfer fluid and the upper limit is approximately 110 degrees Fahrenheit.

FIG. 10 is a simplified schematic diagram of another embodiment of an electrical control system for the system 10. The circuit of FIG. 10 is similar to that of FIG. 9, except that the safety cutout device 818 illustrated in FIG. 9 is not included in FIG. 10 and the circuit of FIG. 10 includes a circuit for continuously controlling the temperature, as opposed to the circuit of FIG. 9 which controls the temperature by cycling the thermoelectric devices 112 on and off. In another embodiment, the safety cutout device 818 illustrated in FIG. 9 and the circuit temperature controller of FIG. 10 are both utilized. In the embodiment illustrated in FIG. 10, a voltage divider with two fixed resistors 1020 and 1024 in series with a variable resistor 1028 feeds the gate of a metal oxide semiconductor field effect transistor (MOSFET) 1026. The variable resistor 1028 is the temperature selector 826. The current flow between the drain and source of the MOSFET 1026 varies with the voltage applied to the gate. By varying the resistance of the variable resistor 1028, the current flowing through the thermoelectric devices 112a ad 112b varies, thereby varying the heating or cooling energy transferred to the heat exchanger 108.

FIG. 11 illustrates another embodiment of a seat heating and cooling system 10′. In one embodiment, a seat heat exchanger 1104 is adapted to fit over a seat 102. In another embodiment, the seat heat exchanger 1104 is adapted to fit inside the seat 102. The seat heat exchanger is part of a seat loop that is connected to a heat exchanger assembly 110′ through tubing 122, 126, 132. The heat exchanger assembly 110′ includes thermoelectric devices 112 and has a second loop that connects to an air heat exchanger 1102 through tubing 1122, 1126, 1132. The seat loop and the second loop have a fluid pumped through the loops by pumps 106, 106′.

The seat heating and cooling system 10′ has two modes of operation: seat heating and seat cooling. With the seat 102 being heated, the thermoelectric devices 112 are powered such that the seat loop is heated. Heated fluid is pumped by pump 106 through tubing 126, circulated through the seat heat exchanger 1104, exhausted through tubing 122 into the heat exchanger assembly 110′, where it is re-heated. The cold side of the thermoelectric devices 112 are warmed by a fluid pumped through a second pump 106′, through tubing 1126 into an air heat exchanger 1102, where the cold fluid is warmed, and back to the heat exchanger assembly 110′, where it is cooled.

With the seat 102 being cooled, the thermoelectric devices 112 are powered such that the seat loop is cooled. Cooled fluid is pumped by pump 106 through tubing 126, circulated through the seat heat exchanger 1104, exhausted through tubing 122 into the heat exchanger assembly 110′, where it is re-cooled. The hot side of the thermoelectric devices 112 are cooled by a fluid pumped through a second pump 106′, through tubing 1126 into an air heat exchanger 1102, where the hot fluid is cooled, and back to the heat exchanger assembly 110′, where it is again re-heated.

In the illustrated embodiment, the air heat exchanger, or radiator, 1102 is a fluid chamber with air cooling fins affixed to the chamber housing. In one embodiment, the radiator 1102 is mounted in an air stream created by the motion of the motorcycle, thereby transferring heat from or to the radiator 1102. In another embodiment, the radiator 1102 is adapted to be part of the motorcycle frame with the frame serving as a heat sink, which is cooled by the ambient air.

FIG. 12 illustrates one embodiment of a seat heat exchanger, or bladder, 1104 and FIG. 13 illustrates a cross-section of the seat heat exchanger, or bladder, 1104. In the illustrated embodiment, the seat heat exchanger 1104 is a bladder formed of two sheets joined at an outer seam 1212 and inside seams 1202, 1204, 1206, 1208, 1210. The inside seams 1202, 1204, 1206, 1208, 1210, along with the outer seam 1212, form channels 1222, 1224, 1226, 1228, 1230, 1232 through which the heat transfer fluid flows. The heat transfer fluid from pump 106 flows through tubing 126 into inlet 1242, through channel 1222 and then into the other channels 1224, 1226, 1228, 1230, 1232, exiting outlet 1244 into tubing 122.

FIG. 13 illustrates a cross-section of the seat heat exchanger, or bladder, 1104 showing the two sheets 1302, 1304 separating to form channels 1228, 1226. The pump 106, by forcing the heat transfer fluid into the bladder 1104, pressurizes the bladder 1104, thereby inflating the bladder 1104 and providing a cushioned seating surface. The channels 1222, 1224, 1226, 1228, 1230, 1232 allow the heat transfer fluid to flow through every portion of the bladder 1104, thereby preventing localized areas of a different temperature.

In one embodiment, the sheets 1302, 1304 of the bladder 1104 are made of a resilient polymer that is impervious to the heat transfer fluid. Those skilled in the art will recognize that other materials can be used to form the sheets 1302, 1304 without departing from the spirit and scope of the present invention. In one embodiment, the seams 1202, 1204, 1206, 1208, 1210, 1212 are formed by welding the two sheets 1302, 1304 together.

FIG. 14 illustrates an exploded view of one embodiment of the heat exchanger assembly 110′. The illustrated embodiment of the heat exchanger assembly 110′ includes a seat side reservoir 1402, a first gasket 1412, a seat side channel plate 1404, a pair of thermoelectric devices 112a, 112b, a radiator side channel plate 1406, a second gasket 1414, and a heat sink plate 1408.

The seat side reservoir 1402, the first gasket 1412, and the seat side channel plate 1404 are secured together by fasteners in openings 1442 that compress the parts 1402, 1412, 1404 forming fluid tight seals. The radiator side channel plate 1406, the second gasket 1414 and the heat sink plate 1408 are secured together by fasteners in openings 1444 that compress the parts 1406, 1414, 1408 forming fluid tight seals. Another set of fasteners are disposed in openings 1512 to compress the seat side of the heat exchanger assembly 110′, the thermoelectric devices 112a, 112b, and the radiator side of the heat exchanger assembly 110′ and provide for heat transfer between the thermoelectric devices 112a, 112b and the two sides of the heat exchanger assembly 110′. Those skilled in the art will recognize that the number and placement of the openings 1442, 1444, 1512 can vary without departing from the spirit and scope of the present invention.

In one embodiment, the gaskets 1412, 1414 are formed of paper and provide a liquid-tight seal between the plates 1402, 1404 and 1406, 1408. In another embodiment, an o-ring provides the liquid-tight between the plates 1402, 1404 and 1406, 1408.

The seat side reservoir 1402, the seat side channel plate 1404, the radiator side channel plate 1406, and the heat sink plate 1408, in one embodiment, are fabricated of aluminum. In another embodiment, the plates 1402, 1404, 1406, 1408 are fabricated of copper. In still another embodiment, the plates 1402, 1404, 1406, 1408 are fabricated of a material suitable for transferring heat between the heat transfer fluid and the thermoelectric devices 112.

The illustrated embodiment shows two thermoelectric devices 112; however, those skilled in the art will recognize that the number of thermoelectric devices 112 can vary without departing from the spirit and scope of the present invention. In one embodiment, the heat sink plate 1408 is attached behind a motorcycle license plate holder with the inlet port 1422 located above the centerline of the seat side reservoir 1402.

The first and second gaskets 1412, 1414 seal the fluid chambers between the seat side reservoir 1402 and the seat side channel plate 1404, and between the opposing side channel plate 1406 and the heat sink plate 1408. In one embodiment, the seat side reservoir 1402 is insulated. The insulation, in one embodiment, is a neoprene insulation, approximately ⅜ inch thick.

In the illustrated embodiment, for the seat side of the heat exchanger assembly 110′, the inlet port 1422 connects to the tubing 122 from the bladder 1104 and the outlet port 1424 connects to the inlet of the pump 106 via tubing 132. The seat side reservoir 1402 and the seat side channel plate 1404 form one heat exchanger that services the seat side fluid loop of the system 10′. For the radiator side of the heat exchanger assembly 110′, the inlet port 1426 connects to the tubing 1122 from the radiator 1102 and the outlet port 1428 connects to the inlet of the pump 106′ via tubing 1132. The radiator side channel plate 1406 and the heat sink plate 1408 form another heat exchanger and that heat exchanger services the radiator side fluid loop of the system 10′.

FIG. 15 illustrates the seat side reservoir 1402, which has two interconnected chambers 1514, 1516 separated by a barrier 1504. The barrier 1504 has gaps at its ends that allow the heat transfer fluid and any entrained air to flow between the two chambers 1514, 1516. The outlet port 1424 draws heat transfer fluid from the channels in the seat side channel plate 1404, through the opening 1432 in the gasket 1412, from one chamber 1518, which is separated from chamber 1514 by a second barrier 1502. The outlet port 1424 is oriented in the plate 1404 such that it is separated from the inlet port 1422, thereby ensuring any entrained or trapped air in the seat side fluid system is trapped in the seat side reservoir 1402.

FIG. 16 illustrates the seat side channel plate 1404, which has a series of channels formed by the barriers 1602 to 1606, 1612 to 1618. One group of the barriers 1602 to 1606 extend from one side of the plate 1404, and another group of barriers 1612 to 1618 extends from the opposite side of the plate 1404. Those skilled in the art will recognize that the number of barriers 1602 to 1606, 1612 to 1618 forming the series of channels can vary in number and configuration without departing from the spirit and scope of the present invention.

The seat side reservoir 1402 is mated to the seat side channel plate 1404 by aligning one corner 1522 of the seat side reservoir 1402 with the corresponding corner 1622 of the seat side channel plate 1404. With the first gasket 1412 between the plates 1402, 1404, a fluid-tight seal is formed between the plates 1402, 1404. The chambers 1514, 1516, 1518 face the series of channels in the channel plate 1404, separated by the first gasket 1412. The first gasket 1412 has an opening 1432 located adjacent the chamber 1518 whereby the heat transfer fluid flows from the seat side reservoir 1402, through the gasket opening 1432, through the series of channels formed by barriers 1602 to 1606, 1612 to 1618, and out the outlet port 1424. The chambers 1514, 1516 in the reservoir 1402 act as an air chamber and contain any entrained or trapped air in the seat side fluid system. An air chamber in a hydraulic system allows air to elastically compress and expand to regulate the flow of a fluid. The seat side reservoir 1402 and the seat side channel plate 1404 form a heat exchanger in which heat is transferred to/from the heat transfer fluid and the thermoelectric device 112.

FIG. 17 illustrates the radiator side channel plate 1406, which has a series of channels formed by barriers 1702, 1706, 1712 to 1716. Inlet port 1426 is at one end of the series of channels and outlet port 1428 is at the opposite end, thereby allowing the radiator side heat transfer fluid to flow from the inlet port 1426, through the series of channels, and out the outlet port 1428. Those skilled in the art will recognize that the number of barriers 1702, 1706, 1712 to 1716 forming the series of channels can vary in number and configuration without departing from the spirit and scope of the present invention.

FIG. 18 illustrates the heat sink plate 1408, which is a solid plate with a cutout 1410 suitable for mounting a power transistor 926 or a power MOSFET 1026. The radiator side channel plate 1406 is mated to the heat sink plate 1408 with the second gasket 1414 between the plates 1406, 1408 and forming a fluid-tight seal between the plates 1406, 1408. The radiator side channel plate 1406 and the heat sink plate 1408 form a heat exchanger in which heat is transferred to/from the heat transfer fluid and the thermoelectric device 112.

FIG. 19 illustrates a block diagram of another embodiment of the system 10, 10′. In the illustrated embodiment, a power supply 802 is connected via a switch 806 to the pumps 106 and the controller 1902. A hot/cold switch 814 toggles the polarity of the voltage applied to the thermoelectric devices 112, thereby controlling whether the seat side fluid system is heated or cooled by the thermoelectric devices 112. The hot/cold switch 814 is connected to a ramp function 1904, which, in one embodiment, slowly ramps the voltage from one polarity to the other instead of abruptly changing the voltage applied to the thermoelectric devices 112. The ramp function 1904 prevents premature failure of the thermoelectric devices 112 caused by localized heating of the conductors when the device 112 is cold. The temperature control 1906, in one embodiment, controls the current flowing through the thermoelectric devices 112, thereby controlling the system 10, 10′ temperature. In another embodiment, the temperature control 1906 is not used and the thermoelectric devices 112 are driven such that they either heat or cool the seat bladder 1104. The controller 1902 is the device that controls the power delivered to the thermoelectric device 112 based on the inputs received from the ramp function 1904 and the temperature control 1906.

The heating and cooling system 10, 10′ includes various functions. The function of changing a temperature of a liquid is implemented by a thermoelectric device 112 thermally coupled to, in one embodiment, a heat exchanger 108 for containing a fluid, and in another embodiment, a heat exchanger formed from a seat side reservoir 1402 mated to a seat side channel plate 1404. The function of transferring the liquid to a seat is implemented by a pump 106.

The function of conducting thermal energy between the liquid and the seat 102 for heat transfer between the seat and an occupant of the seat is implemented, in one embodiment, by a coil 104 coupled to the seat 102, and in another embodiment, by a bladder 1104 having channels 1222, 1224, 1226, 1228, 1230, 1232 through which the fluid flows.

The function of controlling a temperature of the liquid is implemented, in various embodiments, by an temperature controller 824, 1904. In one embodiment, the temperature controller 824, 1904 provides power to the thermoelectric device 112. In another embodiment, the temperature controller 824, 1904 includes a power transistor 1026 circuit that provides for variable temperature control of the thermoelectric device 112. In one embodiment, the temperature controller 824 includes a safety cutout device 818. In another embodiment, the temperature controller 824 includes a temperature sensor 828. In another embodiment, the temperature controller 824, 1904 includes a hot/cold switch 814. In one embodiment, the temperature controller 1904 includes a ramp function 1904.

The function of transferring thermal energy between the structure for changing the temperature and the environment is implemented, in one embodiment, by a heat sink 114 thermally coupled to the thermoelectric device 114. The heat sink 114, in one embodiment, has a fan 116 forcing air across the heat sink 114. In another embodiment, the function of transferring thermal energy is implemented by a heat exchanger formed from a radiator side channel plate 1406 mated to a heat sink plate 1408 in fluid communication with a radiator 1102.

The function of trapping air is performed by the air trap chambers 1514, 1516 in the seat side reservoir 1402 when the seat side reservoir 1402 is mated to the seat side channel plate 1404.

From the foregoing description, it will be recognized by those skilled in the art that a heating and cooling system for a vehicle seat has been provided. The seat relies upon conductive heat transfer between a liquid heat transfer fluid and the occupant of the seat. The conductive heat transfer is particularly suitable for exposed seats, such as on a motorcycle or tractor. In one embodiment, a heat transfer fluid transfers heat from a thermoelectric device through a heat exchanger to a fluid that is circulated through a heat exchanger, or bladder, coupled to the seat. The cold side of the thermoelectric device, in one embodiment, is air cooled by fans. In another embodiment, the cold side of the thermoelectric device is coupled to another heat exchanger in which warm fluid is circulated. The cooled fluid is pumped to a radiator, where it is warmed again. In another embodiment in which the heat flow is reversed, the heat transfer fluid transfers heat from the heat exchanger or bladder coupled to the seat to the thermoelectric device.

While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.