Automatic Seat Thermal Comfort Control System and Method

Abstract

A method for controlling the thermal comfort of an occupant includes the following steps: driving the temperature in the seating area to a temperature set point (54), maintaining the temperature set point in the seating area for a preset time (56), and adjusting the temperature of the seating area to a corrected temperature set point (58) based on an equivalent uniform temperature related to the vehicle compartment conditions and the gender of the occupant.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority of U.S. Provisional Application No. 62 / 951,289, filed on December 20, 2019, and the U.S. Provisional Application is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to an occupant seat thermal comfort control system and method that automatically controls the temperature of the seat surface and / or the adjustment of the occupant neck rest to achieve occupant thermal comfort. Background Art

[0004] Vehicles typically include heating, ventilation, and air - conditioning (HVAC) systems to thermally condition the air inside the vehicle cabin. Typical modern vehicles also include seats with thermal effectors that are controlled to achieve occupant thermal comfort. The thermal effectors can include heating and / or cooling elements that further heat or cool the occupant through the seat support surface.

[0005] Although many systems have been proposed, it is difficult to implement a commercial seat thermal control system to effectively and efficiently achieve occupant thermal comfort using the seat, especially for the numerous variable conditions present in the vehicle cabin. Summary of the Invention

[0006] In one exemplary embodiment, a method of controlling occupant thermal comfort includes the steps of driving the temperature in the seating area to a temperature set - point, maintaining the temperature set - point in the seating area for a preset time, and adjusting the temperature in the seating area to a corrected temperature set - point based on an equivalent uniform temperature related to the vehicle cabin conditions and the occupant's gender.

[0007] In a further embodiment of any of the above - mentioned exemplary embodiments, the driving step includes a temperature set - point determined based on the vehicle ambient temperature, the vehicle cabin temperature, and / or the occupant's gender.

[0008] In a further embodiment of any of the above - mentioned exemplary embodiments, the method includes a plurality of seating areas including a seat cushion and a seat back. The seat cushion and the seat back each have different temperature set - points.

[0009] In a further embodiment of any of the above - mentioned exemplary embodiments, the method includes a plurality of seating areas including a seat cushion and a seat back. When the first of the plurality of seating areas reaches its temperature set - point, the maintaining step begins after the driving step.

[0010] In a further embodiment of any of the above exemplary embodiments, the method includes a plurality of seating areas, the plurality of seating areas including seat cushions and seat backs. The holding step includes determining a holding time for each of the plurality of seating areas. When the first of the plurality of seating areas reaches its holding time, the adjustment step begins after the holding step.

[0011] In a further embodiment of any of the above exemplary embodiments, the corrected temperature setpoint increases with the equivalent uniform temperature.

[0012] In a further embodiment of any of the above exemplary embodiments, the corrected temperature setpoint is maintained within a corrected temperature setpoint range. The corrected temperature setpoint range during heating is greater than the corrected temperature setpoint range during cooling.

[0013] In a further embodiment of any of the above exemplary embodiments, the method includes a plurality of seating areas, the plurality of seating areas including seat cushions and seat backs. The corrected temperature setpoints of the seat cushions and seat backs are independently adjusted based on different estimated levels of the occupant's clothing related to the seat cushions and seat backs.

[0014] In a further embodiment of any of the above exemplary embodiments, the estimated level of the occupant's clothing is determined based on a combination of the vehicle ambient temperature and gender.

[0015] In a further embodiment of any of the above exemplary embodiments, according to the equation ΔT amb_back_i = A - B×T amb the estimated level of the occupant's clothing for the seat cushion is determined, where A and B are preset constants.

[0016] In a further embodiment of any of the above exemplary embodiments, according to the equation ΔT amb_cushion_i = C×T amb the estimated level of the occupant's clothing for the seat back is determined, where C is a preset constant.

[0017] In a further embodiment of any of the above exemplary embodiments, the method includes a plurality of seating areas, the plurality of seating areas including seat cushions and seat backs. The corrected temperature setpoints of the seat cushions and seat backs are independently adjusted based on the occupant's gender.

[0018] In a further embodiment of any of the above exemplary embodiments, the corrected temperature setpoint for the seat cushion and / or seat back for a female is lower than the corrected temperature setpoint for the seat cushion and / or seat back for a male.

[0019] In a further embodiment of any of the above exemplary embodiments, for a female, the corrected temperature setpoint for the seat back is lower than the corrected temperature setpoint for the seat cushion.

[0020] In a further embodiment of any of the above exemplary embodiments, the calibration temperature setpoint is based on control loop feedback on respective surface temperature sensors located in the high pressure zones created by occupant contact.

[0021] In a further embodiment of any of the above exemplary embodiments, the controller is programmed to perform the steps of any one or more of the foregoing embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present disclosure may be further understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0023] Figure 1 is a schematic view of a vehicle having a climate-controlled seat and control system configured to achieve occupant thermal comfort.

[0024] Figure 2 is an example arrangement of thermal effectors in the seating area of the adjustable seat.

[0025] Figure 3 is a flowchart showing a method of operating the disclosed thermal comfort control system.

[0026] Figure 4A is a depiction Figure 3 of a flowchart of a first phase of the method shown.

[0027] Figure 4B is a description Figure 3 of a flowchart of a second phase of the method shown.

[0028] Figure 4C is a description Figure 3 of a flowchart of a third phase of the method shown.

[0029] Figure 5 is a graph showing Figures 3 - 4C the relationship between the temperature and time of the seating area using the method shown.

[0030] Figure 6 is a flowchart schematically showing the method disclosed during three phases.

[0031] Figure 7 is a schematic diagram of the system of the method disclosed.

[0032] The foregoing paragraphs, claims, or embodiments, examples, and alternatives of the following specification and drawings may be employed independently or in any combination, including any one of their respective aspects or individual features. Features described in connection with one embodiment apply to all embodiments unless the features are incompatible. DETAILED DESCRIPTION

[0033] The present disclosure relates to a seat thermal comfort control system and method that automatically sets an initial temperature for seat surface and neck rest adjustment to achieve comfort and then automatically adjusts the temperature based in part on the occupant's equivalent homogeneous temperature (EHT). EHT represents the total thermal effect on the occupant, which, as a measure of the occupant's heat loss, produces a whole-body thermal sensation. EHT takes into account the combined convective, conductive, and radiative effects on the occupant and combines these effects into a single value, which is particularly useful for simulating non-uniform thermal environments. An example calculation of EHT can be found in the paper by Han, Taeyoung and Huang, Linjie, titled “A Model for Relation a Thermal Comfort Scale to EHT Comfort Index,” published in SAE Technical Paper 2004-01-0919, 2004. As described in the SAE paper, which is incorporated herein by reference in its entirety, the modeled thermal environment is affected by the “breathing” air temperature, mean radiant temperature (MRT), air velocity, solar load, and relative humidity.

[0034] The disclosed control proceeds through three different control periods or phases. Thermal energy is transferred to the passenger via various thermal regulation devices or thermal effectors located in the seat and optionally in the area surrounding the passenger.

[0035] In each phase, the controller determines parameters for controlling the transfer of thermal energy to the occupant to achieve thermal comfort. Thermal control parameters are determined for each thermal regulation device and / or each seating area. For example, the thermal control parameters correspond to the desired surface temperature and the regulated air temperature and velocity. A control loop feedback is used to determine when the desired thermal conditions are reached and to adjust the desired thermal conditions. The feedback is provided by sensors associated with the thermal regulation devices and optionally by additional sensors located in the seat (e.g., a seat surface temperature sensor in or under the seat trim).

[0036] Reference Figure 1 , vehicle 10 includes a passenger compartment 22 having a climate-controlled seat 12. In one example, seat 12 includes seat cushion, backrest, and / or neck rest thermal effectors 14, 16, 18. In response to various environmental and occupant inputs, controller 20 communicates with thermal effectors 14, 16, 18 to determine and achieve optimal occupant thermal comfort for any occupant on seat 12. In one example, a passenger compartment air temperature sensor 24 (C; T cabin ), a passenger compartment air velocity sensor 26 (V; V cabin ), a vehicle ambient (i.e., outside) temperature sensor 28 (A; T amb) The solar radiation load sensor 30 (S; solar load) and the occupant recognition sensor 32 (O; e.g., gender) communicate with the controller 20 to provide inputs related to achieving occupant thermal comfort. The cabin air speed is related to the airflow within the cabin from the HVAC system. It should be understood that while specific environmental inputs 24, 26, 28, 30 and occupant inputs 32 are disclosed herein, other environmental (e.g., vehicle interior radiation) and occupant inputs (e.g., occupant clothing, age, weight, height) are also necessary or preferred for determining the occupant EHT that can be provided to the controller 20 (see Figure 7 ).

[0037] Reference Figure 2 , schematically shows an example seating area thermoeffecter configuration for heating and cooling. Each of the seat cushion, backrest, and headrest can be an independent or discrete seating area, or each thermoeffecter or group of thermoeffecters can correspond to a discrete seating area. It should be understood that different and / or additional thermal components and sensors can be used. The illustrated configuration is for illustrative purposes only. The seat 12 includes a seat cover 34 that provides a seat support surface. A surface sensor 36 can be disposed within the seat cover 34. The surface sensor 36 can correspond to a temperature sensor, which can be used alone or in combination with other temperature sensors in the seat to simulate the heat flux between the seat support surface and the occupant. Alternatively, the surface sensor 36 can be a heat flux sensor.

[0038] The thermoelectric assembly 38 can be used to provide thermal regulation to the occupant, such as cooling. The thermoelectric assembly 38 includes an inlet duct 42 for receiving cabin air. A fan 44 or blower can be positioned within the duct of the assembly 38 in any suitable manner. The cabin air flows through a thermoelectric device (TED) 46 that provides a regulated side and a waste side. In this example, the regulated side provides cooled air to an air conditioning duct 50, while the waste side provides heated air to an exhaust duct 48. The regulated air from the air conditioning duct 50 can flow to the seat cover 34 through various channels within the seat in any suitable manner. The TED 46 can include a temperature sensor that is configured to measure the temperature of the primary side and thereby measure the temperature of the air regulated by the primary side.

[0039] The resistive heating element 40 can be used to provide heating to the seat cover 34. The heating element 40 can include a temperature sensor that is configured to measure the temperature of the heating element 30 and thereby measure the temperature of the corresponding seat surface.

[0040] The controller 20 includes a thermal comfort control system method 52 for regulating the thermoeffecters based on inputs and data sets to achieve a desired occupant thermal comfort.

[0041] The method 52 includes a first stage 54 (Stage 1) to drive the temperature in the seating area (e.g., seat cushion, backrest, and / or neck rest) to a desired temperature set point (T set ). Before entering the third stage 58 (Stage 3), a second stage 56 (Stage 2) holds the temperature in the seating area at the desired temperature set point for a preset time. In the third stage 58 (Stage 3), the temperature in the seating area is adjusted based on the Equivalent Homogeneous Temperature (EHT). The control methods for the three stages are in Figures 4A - 4C and are described in more detail in conjunction with Figure 6 and Figure 7 .

[0042] Referring to Figure 4A , the first stage 54 begins by determining the temperature set point for each in the seating area, as shown in block 60. The set point is determined based on various inputs 62, such as the ambient temperature (T amb ), the cabin temperature (T cabin ), and / or the occupant's gender (Gender). A look-up table 64 can be provided based on, for example, the temperature set points and the cabin air speed in a 6×6×2 table. The temperature set points can be determined empirically during the development process. Exemplary initial set points for the seat cushion are 29 °C for cooling and 40 °C for heating; exemplary initial set points for the backrest are 29 °C for cooling and 42 °C for heating; exemplary initial set points for the neck rest are 15 °C + / - 1 °C for cooling and 46 °C + / - 1 °C for heating, with a blower volume flow rate of 0.8 CFM (see Figure 6 and Figure 7 ).

[0043] Using the determined set points, which may be the same or different between the seating areas (e.g., T set Seat cushion: 2 zones heating each surface, 1 zone cooling each surface; T set Backrest: 2 zones heating each surface, 1 zone cooling each surface; T set Neck rest: 1 zone heating, 1 zone cooling; V se Neck rest: 1 zone heating, 1 zone cooling), the thermal effectors for the respective seating areas are driven to the temperature set point, as shown in block 66. At this time, an operation timer (TIMER operation ) is started, as shown in block 68, which runs from the time the control system is started.

[0044] As shown in block 70, a feedback loop is provided to determine whether any seating area has reached its temperature set point. This can be determined based on one or more inputs such as heater NTC, TED NTC, blower speed and / or voltage, seat surface NTC, neck rest regulator PTC heater NTC, neck rest regulator blower speed and / or voltage, and / or any other suitable sensors. The response time required to reach the desired seat surface temperature is much longer than the response time required to reach the desired neck rest adjustment temperature. Therefore, the operating time of stage 1 depends on the time required to reach the desired seat surface temperature, rather than the neck rest adjustment temperature. If any seating area has reached the temperature set point, stage 1 is exited for all temperature-enabled seating areas and stage 2 is started. If no seating area has reached the temperature set point, the elapsed preset time is referenced based on an operation timer, as shown in block 72. If no heating zone has been driven to its set point within the preset time, stage 1 ends and stage 2 starts.

[0045] As Figure 4B shown, stage 2 begins with determining the hold time for each seating area (block 74) based on various inputs 76 and a look-up table 78. In one example, the inputs 76 are vehicle ambient temperature, cabin temperature, and gender. The table can be provided as a 6×6×2 table. The thermal effector in each seating area is held at the desired temperature, which can correspond to the temperature set point for a given seating area, as shown in block 80. A hold time timer 82 (TIMER holdtime ) is started.

[0046] The feedback loop checks whether the seating area hold time has been reached, as shown in block 84. If the hold time has not been reached, the thermal effector in each seating area is continued to be held at the desired temperature, e.g., the temperature set point for a given seating area. If the seating area hold time has been reached, a check is performed to determine whether the maximum thermal effector operating time (t2 operation ,max) has been reached based on the operation timer started in block 68. If the maximum thermal effector operating time has not been reached (block 86), the thermal effector is held at the desired temperature. Once the hold time and the operating time have been reached, stage 2 is exited and stage 3 starts. In one example, stages 1 and 2 are completed in less than 6 minutes.

[0047] Figure 4CThe third stage 58 shown in FIG. 1 determines an equivalent uniform temperature (EHT) for each seating zone, as shown in block 88. The EHT is determined based on inputs 90 and one or more tables 92. Exemplary EHT inputs 90 are based on gender and cabin environmental conditions (cabin temperature, cabin air velocity, and solar load), which can be organized in tables for each of the heating and cooling scenarios. An example table is shown below, where EHT X, X is the EHT for a given ambient temperature (T amb ) and radiant heat (Q rad )’s EHT.

[0048]

[0049] The EHT for each position in the table may be determined, for example, according to the following equation:

[0050]

[0051] in,

[0052] τ is the transmittance,

[0053] F is the field of view factor (varies from vehicle to vehicle, but remains constant)

[0054] T is the temperature (from Q solar and T amb measurement or calculation)

[0055] Q solar is the solar load (from the sensor).

[0056] As can be appreciated from the above equation, convection sources are neglected (ie, EHT=MRT) since the effectors will be controlled as part of the disclosed thermal conditioning method. Based on the temperature of the ventilation air provided by the HVAC and the air velocity from the vents, convection can be added to the EHT equation above.

[0057] It is desirable to compensate for the effects of clothing on the occupant so that a desired amount of heating or cooling can be applied by the thermoeffectors.

[0058]

[0059] therefore

[0060] ΔTamb_back_i=Q*R clo,back

[0061] Determine R for specific gender using the occupant dataset clo,back The intercept (X) and slope (Y) of the curve are then provided with a correction (Z) to account for the effect of ambient temperature (e.g., 20°C).

[0062] R clo,back,male= X - Y * T amb

[0063] R clo,back,20C,male = Z R clo,back,male

[0064] R clo,back,male = R clo,back -R clo,20C

[0065] The vehicle cabin environmental conditions correspond to ΔT amb_i , and the gender information corresponds to ΔT gender_i (see Figure 6 ). As shown in the chart in Figure 6 , for both heating and cooling scenarios, the corrected temperature setpoint (T set_i ) increases as the vehicle cabin environmental conditions increase. The corrected temperature setpoint (T set_i ) is maintained within a preset range of EHT (i.e., ΔT(T set – EHT)), where EHT is the preset temperature.

[0066] At block 94, the EHT compensation factor (ΔT amb_i , ΔT gender_i ) for each seating area is calculated based on interpolation, and at block 96, the temperature setpoint for each seating area is calculated (see Figure 6 ; T set_i = T set + ΔT amb_i + ΔT gender_i ). In one example, the compensation factors for ΔT amb_i and ΔT gender_i correspond to the coefficients A, B, C, D, and E, where ΔT amb_back_i = A - B × T amb_i ; ΔT amb_cushion_i = C × T amb _ i ; ΔT gender_back_i = 0 (if male) and -D (if female); and ΔT gender_cushion_i = 0 (if male) and -E (if female).

[0067] The compensation factors are determined empirically during development. Example correction factors include ΔT amb_back_i = 5.37 - 0.27 × T amb ; ΔT amb_cushion_i = 0 × ΔT amb ; ΔT gender_back_i = -2, if female; and ΔT gender_cushion_i = -0.5, if female (see Figure 6). The thermal effector in each seating area is driven to a corrected temperature set point (T set_i ), or maintained within the corrected temperature set point range for the remainder of Phase 3, as shown in block 98. This control loop can be repeated approximately every 30 seconds during the entire driving cycle of each vehicle 10. The corrected temperature set point is based on control loop feedback from individual surface temperature sensors located in the high pressure zones created by occupant contact.

[0068] As Figure 5 shown, the seat surface temperature is graphically displayed over time through three thermal comfort control system phases (P1, P2, P3). t1 occurs at approximately one (1) to two (2) minutes of operation after the sensible expected time. t1 occurs before the occupant achieves comfort, and t2 begins at the end of the hold time. t2 occurs at approximately five (5) to seven (7) minutes of operation.

[0069] It should also be understood that although a specific component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit therefrom. Although specific step sequences are shown, described, and claimed, it should be understood that the steps can be performed in any order, separately or in combination, unless otherwise stated, and still benefit from the present invention.

[0070] Although the different examples have specific components as shown in the drawings, embodiments of the present invention are not limited to these specific combinations. Some components or features from one example can be used in combination with features or components from another example.

[0071] Although example embodiments have been disclosed, those of ordinary skill in the art will recognize that certain modifications will fall within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.

Claims

1. A method for controlling the thermal comfort of an occupant, comprising the following steps: driving the temperature in the seating area to a temperature set point by at least one thermal effector; maintaining the temperature set point in the seating area for a preset time by the at least one thermal effector; and adjusting the temperature in the seating area to a corrected temperature set point by the at least one thermal effector based on an equivalent uniform temperature related to the vehicle compartment conditions and the occupant's gender, wherein the corrected temperature set point of the seating area is based on an estimated level of the occupant's clothing, and the estimated level of the occupant's clothing is determined based on a combination of the vehicle ambient temperature and gender, and the vehicle ambient temperature is the temperature outside the vehicle.

2. The method according to claim 1, wherein the driving step includes determining the temperature set point based on the vehicle ambient temperature, the vehicle compartment temperature, and / or the occupant's gender.

3. The method according to claim 1, comprising a plurality of seating areas, the plurality of seating areas including a seat cushion and a seat backrest, and the seat cushion and the seat backrest each having a temperature set point different from each other.

4. The method according to claim 1, comprising a plurality of seating areas, the plurality of seating areas including a seat cushion and a seat backrest, wherein when the first of the plurality of seating areas reaches its temperature set point, the maintaining step starts after the driving step.

5. The method according to claim 1, comprising a plurality of seating areas, the plurality of seating areas including a seat cushion and a seat backrest, wherein the maintaining step includes determining the holding time for each of the plurality of seating areas, and when the first of the plurality of seating areas reaches its holding time, the adjusting step starts after the maintaining step.

6. The method according to claim 1, wherein the corrected temperature set point increases with the equivalent uniform temperature.

7. The method according to claim 6, wherein the corrected temperature set point is maintained within a corrected temperature set point range, and the corrected temperature set point range during heating is greater than the corrected temperature set point range during cooling.

8. The method according to claim 1, comprising a plurality of seating areas, the plurality of seating areas including a seat cushion and a seat backrest, wherein the corrected temperature set points of the seat cushion and the backrest are independently adjusted based on different estimated levels of the occupant's clothing related to the seat cushion and the backrest.

9. The method according to claim 1, wherein According to the equation ΔT amb_back_i = A - B×T amb to determine the estimated level of the occupant's clothing for the seat cushion, where A and B are preset constants.

10. The method according to claim 9, wherein Determine an estimated level of occupant clothing for a backrest according to the equation ΔT amb_cushion_i = C × T amb where C is a preset constant.

11. The method according to claim 1, comprising a plurality of seating areas, the plurality of seating areas including a seat cushion and a seat backrest, wherein the corrected temperature set points of the seat cushion and the backrest are independently adjusted based on the occupant's gender.

12. The method according to claim 11, wherein the corrected temperature set point of the seat cushion and / or the backrest for a female is lower than the corrected temperature set point of the seat cushion and / or the backrest for a male.

13. The method according to claim 12, wherein for a female, the corrected temperature set point for the backrest is lower than the corrected temperature set point for the seat cushion.

14. The method according to claim 1, wherein the corrected temperature set point is based on the control loop feedback on each surface temperature sensor located in the high-pressure area generated by the occupant's contact.

15. The method according to claim 1, wherein, the step of driving is performed at a first time, and the step of holding is performed from the first time to a second time, and the step of adjusting is performed from the second time to a third time, wherein the first time and the second time occur before the occupant obtains thermal comfort, and the third time occurs after the occupant obtains thermal comfort.

16. The method according to claim 15, wherein, the second time occurs between 1 minute and 2 minutes from the first time, and the third time occurs between 5 minutes and 7 minutes from the first time.

17. The method according to claim 15, wherein, the second time is determined based on the ambient temperature, the cabin temperature, and the gender.

18. The method according to claim 15, wherein, if the desired temperature is not reached by the second time, the maximum effector operation time of the at least one thermal effector is checked, and if the maximum effector operation time has not been reached, the at least one thermal effector is maintained at the desired temperature.

19. A controller programmed to perform the steps according to any one of claims 1 - 18.

20. A seat comprising the controller according to claim 19.

21. A vehicle comprising the seat according to claim 20.

22. A vehicle comprising the controller according to claim 19.

23. A seat for controlling occupant thermal comfort, which comprises: a seat having a seating area; and a controller configured to drive the temperature in the seating area to a temperature set point by at least one thermal effector, the controller being configured to hold the temperature set point in the seating area for a preset time by the at least one thermal effector, and the controller being configured to adjust the temperature in the seating area to a corrected temperature set point by the at least one thermal effector based on an equivalent uniform temperature related to the cabin conditions and the occupant gender, wherein the corrected temperature set point of the seating area is based on an estimated level of the occupant's clothing, and the estimated level of the occupant's clothing is determined based on a combination of the vehicle ambient temperature and the gender, and the vehicle ambient temperature is the temperature outside the vehicle.

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