Method for estimating surface temperature of ventilated seat

Abstract

A method for estimating a surface temperature of a ventilated seat. A heat transfer rate to or from the material layer is determined based on a temperature applied to the material layer by the convective air. A temperature of the material layer is estimated based on a heat transfer rate to or from the material layer. A heat transfer rate to or from the finishing layer is determined based on the temperature of the material layer applied to the finishing layer. A rate of change in the surface temperature is calculated based on a rate of heat transfer to or from the finishing layer. The surface temperature is estimated based on the rate of change of the surface temperature.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 434,562 (filed December 22, 2022), which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] The present disclosure relates to a method for estimating the temperature of a surface that can be ventilated by convective air flow. Background Art

[0004] Some climatized vehicle systems operate at a set of predetermined, discrete set points that are selected by the occupant using actuation of buttons, dials, and the like. One disadvantage of these systems is the inability to adjust the airflow rate between set points. Another disadvantage is the requirement for the occupant to manually change the airflow rate set point during operation of the vehicle to achieve and / or maintain comfort.

[0005] To address these challenges, some climate-adapted vehicle systems employ sensors that monitor parameters such as temperature, blower speed, outside temperature, solar radiation, cabin air temperature, and humidity. Set points selected by the occupant are then associated with these parameters via a lookup table, and the operation of the blower is therefore guided by both the set points and the parameters. Noise, vibration, and harshness (NVH) caused by the blower can also be taken into account. These systems operate under a limited number of predetermined scenarios. One drawback of these systems is the extensive calibration effort required to account for the possible scenarios a vehicle may face. As an example, the system is typically calibrated to account for driving in different seasons, geographic climates, weather conditions, and the like. Furthermore, because these parameters affect different vehicle builds differently, calibration is performed for each make, model, year, and trim level of vehicle.

[0006] Some climate-adapted vehicle systems calibrate the airflow rate to a specific cabin air temperature. However, cabin air temperature does not accurately represent the temperature felt by occupants at the surface and is subject to constant fluctuations. While providing sensors close to the surface can detect the temperature of that surface, several challenges are recognized. Blower operation may require repeatable accuracy and precision in the location of these sensors to coordinate with the calibration of the system. However, consistent location of these sensors can be difficult during the manufacturing process. Furthermore, the automotive industry is focused on reducing costs, so additional sensors and their attendant costs are generally not a favorable solution. Sensors positioned in or on compressible layers (such as the spacer layer in a seat) may be felt by the occupants, negatively impacting comfort. Furthermore, compressible layers can subject the sensors to repeated wear, which can degrade the integrity of the sensors over time.

[0007] Some seats are manufactured with groove lines defined between adjacent sections of material (e.g., adjacent cushion materials). Air can escape along the groove lines from the seat surface to which it is intended to be delivered, and thus leak from the system. Conventional methods for controlling ventilated seats do not account for this leakage.

[0008] A method is needed to accurately and precisely estimate the temperature felt by an occupant at a surface.

[0009] What is needed is a method for estimating surface temperature using existing sensor and / or controller hardware.

[0010] What is needed is a method that provides control of a blower to provide a dynamic air flow that is not constrained by a predetermined set point.

[0011] What is needed is a method that eliminates the need for calibration to populate the lookup table.

[0012] What is needed is a method of controlling a blower between discrete set points.

[0013] What is needed is a method for controlling a blower across a continuous range of possible environmental conditions that may be realized within the cabin of a vehicle.

[0014] What is needed is a method of controlling the operating mode (ON / OFF) and / or set point (eg, low, medium, and high airflow rates) of the blower based on the steady-state temperature of the seating surface. Summary of the Invention

[0015] The present disclosure provides a method that can address at least some of the needs identified above. The method can estimate the surface temperature of a ventilated seat. The method can include determining a heat transfer rate to or from a material layer based on a temperature applied to the material layer by convective air. The method can also include estimating the temperature of the material layer based on the heat transfer rate to or from the material layer.

[0016] The method may include determining a rate of heat transfer to or from the trim layer based on a temperature of a layer of material applied to the trim layer. The method may include calculating a rate of change of surface temperature based on the rate of heat transfer to or from the trim layer.

[0017] The method may include updating the estimated surface temperature of the trim layer from a previous program cycle based on the rate of change of the surface temperature and the estimated surface temperature of the trim layer from the previous program cycle.

[0018] Convective air may flow through one or more ventilation holes formed in the material layer and / or the pores in the material layer.

[0019] This convection air may be drawn from the cabin of the vehicle.

[0020] This convective air may be exempt from thermal conditioning by heating and / or cooling equipment.

[0021] The layer of material may be a spacer layer disposed between the trim layer and the fluid distribution device.

[0022] The method may further include determining a second heat transfer rate to or from the trim layer based on a second temperature applied to the trim layer.

[0023] The second temperature may be applied by cabin air.The cabin air may be located above the trim layer.

[0024] The method may further include determining a third heat transfer rate to or from the trim layer based on a third temperature applied to the trim layer.

[0025] The third temperature may be applied by an occupant.

[0026] The rate of change of the surface temperature may additionally be based on the second heat transfer rate and / or the third heat transfer rate.

[0027] The method may further include determining an occupancy state of the ventilated seat.

[0028] For an occupied seat, the rate of change of the surface temperature may additionally be based on the second heat transfer rate and the third heat transfer rate.

[0029] For unoccupied seats, the rate of change of surface temperature may additionally be based on the second heat transfer rate.

[0030] The rate of heat transfer to and from the material and trim layers is affected by the thermal resistance of the material and trim layers, respectively. The thermal resistance of the material and trim layers can be selected based on whether the ventilated seat is occupied.

[0031] The rate of heat transfer to or from the material layer may be affected by the surface area over which the first temperature is applied. This surface area may be selected based on whether the ventilated seat is occupied or not.

[0032] The estimated temperature and / or rate of change of the surface temperature for the material layer may be based on one or more additional heat transfer rates.

[0033] The one or more additional heat transfer rates relative to the material layer may include a heat transfer rate between the fluid distribution device and the material layer.

[0034] The first temperature may be sensed by a local sensor in a cabin of a vehicle where the ventilated seat is located.

[0035] The method may further include controlling the blower, including: receiving a surface temperature; receiving a cabin air temperature; optionally, receiving a relative humidity; and adjusting a duty cycle of the blower based on the surface temperature, the cabin air temperature, the relative humidity, or any combination thereof.

[0036] The present disclosure provides a system that can address at least some of the needs identified above. The system can implement the method described above. The system can include: a blower operating in a push or pull mode; a fluid dispensing device (e.g., in the form of a bag) with a portion oriented toward an air-permeable seat surface; a temperature sensor (e.g., onboard the blower); and a relative humidity sensor (e.g., located near the seat surface). BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Ventilated seats are shown.

[0038] Figure 2 is a schematic diagram of a system of the present teachings.

[0039] Figure 3 is a flow chart of a method of the present teachings. DETAILED DESCRIPTION

[0040] The present disclosure provides a method for dynamically estimating the temperature of a surface. The surface can be any exposed surface of a vehicle component. The vehicle component and its exposed surface can be located within the vehicle's cabin. The surface can be on a finished surface, i.e., an exposed, visible surface of the vehicle that is typically touched by occupants (e.g., leather, fabric, or the like). The vehicle component can include any component that is touched by occupants.

[0041] The surface can exchange heat with convective air, one or more material layers, an occupant, cabin air, a radiant heat source, or any combination thereof. Convective air can be drawn into the surface and / or exhausted from the surface. Convective air can pass through one or more material layers located beneath the surface.

[0042] The vehicle component may include a seat. The seat may include a backrest portion, one or more backrest cushions, a seat portion, one or more seat cushions, a headrest, or any combination thereof. The seat may be ventilated. That is, convective air may flow through the seat, affecting the temperature of the seat, extracting heat from the occupant, extracting moisture from the occupant, forcing air toward the occupant, or any combination thereof.

[0043] Typically, a vehicle seat may be laid up with a trim layer, a fluid distribution device, and one or more layers of material (eg, spacer layers) disposed therebetween.

[0044] A passenger may sit on and / or contact one or more surfaces of the seat. These surfaces may alternatively be referred to herein as a trim layer. The trim layer may include one or more ventilation holes and / or be made of a porous material. Thus, convective airflow may pass through the trim layer. The trim layer may include fabric, leather, the like, or any combination thereof.

[0045] Typically, one or more material layers may separate the fluid distribution device from the trim layer. The material layer may function to protect the fluid distribution device, provide comfort to the occupant, modulate the rate of heat transfer through the material layer by virtue of the material and thickness of the material layer, promote air flow therethrough, or any combination thereof. The material layer may include one or more woven fabrics, nonwoven fabrics, films, leather, foam, mesh, air pockets, or any combination thereof.

[0046] The material layer may include one or more ventilation holes. The ventilation holes may extend at least partially from one side of the material layer to an opposite side of the material layer. The ventilation holes may direct air flow between the finishing layer and the fluid distribution device. Air may pass through the ventilation holes.

[0047] The material layer can be porous. The porosity of the material layer can allow air to flow through the material layer. By way of example, the material layer can be made of open-cell foam. The present disclosure contemplates that both a porous material layer and ventilation holes formed in the material layer can be employed.

[0048] Although this disclosure discusses arrangements of one material layer (eg, a spacer layer) disposed between the fluid distribution device and the trim layer, this disclosure also contemplates other layer arrangements, such as two or more, or even three or more material layers.

[0049] Furthermore, the present disclosure contemplates a fluid distribution device disposed in direct contact with the trim layer. In such an arrangement, the heat transfer rate between the fluid distribution device and the trim layer can be calculated according to the present teachings.

[0050] The fluid distribution device can function to distribute air across a surface area (in a push mode) or to collect air across a surface area (in a pull mode). The fluid distribution device can include one or more channels and / or a housing through which air flows. The fluid distribution device can define an internal volume through which air flows.

[0051] In some aspects, a material layer can define at least a portion of a fluid distribution device. For example, a layer of a seat can include one or more channels formed therein, the channels being exposed or open on a surface of the layer; a spacer layer can be disposed on the layer and over the one or more channels to define an enclosed volume of the one or more channels through which air can pass.

[0052] The shell can be rigid, flexible, or both. The shell can include a bag. The shell can include one or more air-permeable portions. The one or more portions can be oriented toward the occupant.

[0053] The fluid distribution device may include a spacer material. The spacer material may at least partially prevent compression of the seat from squeezing opposing surfaces of the fluid distribution device and restricting airflow. For flexible fluid distribution devices, the spacer material may maintain a distance between opposing surfaces of the fluid distribution device. The spacer material may include a mesh, foam, a woven textile, a non-woven textile, or any combination thereof. The spacer material may be air permeable.

[0054] In push mode, air can be directed by the fluid distribution device across the surface area of the material layer and / or the trim layer. The air can be directed to vents formed in the material layer and / or pores in the material layer. The air can be directed to vents formed in the trim layer and / or pores in the trim layer. The air can be discharged toward the occupant.

[0055] In pull mode, air can be drawn from the surface of the seat and into the fluid distribution device. The air can be exhausted at a port on the fluid distribution device. The air can ultimately be exhausted into the cabin of the vehicle. The port can be in fluid communication with one or more blowers.

[0056] Non-limiting examples of ventilated seats are described in US Patent No. 7,735,932 B2 and International Publication No. WO 2007 / 142972 A2, both of which are incorporated herein by reference for all purposes.

[0057] Ventilation may be regulated by one or more blowers. Non-limiting examples of blowers are described in International Publication No. WO 2008 / 115831 Al and US Pat. No. 9,121,414 B2, which are incorporated herein by reference for all purposes.

[0058] The blower can be controlled to provide an airflow corresponding to an operating mode and / or set point. The operating mode can be ON or OFF. The set point can include a temperature set point, an airflow rate set point, or both. The set point can be selected from a range of set points.

[0059] The operating mode and / or set point may be determined by occupant actuation of one or more knobs, buttons, dials, toggles, switches, the like, or any combination thereof (also referred to herein as a human-machine interface).

[0060] The operating mode and / or set point can be determined by an autonomous control system. These systems can consider one or more sensor inputs and autonomously adjust the set point via one or more controllers. The autonomous control system can operate in conjunction with input from a human-machine interface.

[0061] The blower can be operated by a duty cycle (e.g., pulse width modulation). The duty cycle can be selected to achieve a desired airflow rate.

[0062] The dynamic temperature estimation of the present disclosure takes into account the complex heat exchange system that occurs throughout the vehicle. Such heat exchanges may be caused by external temperature, humidity, solar radiation, occupant body temperature, cabin air temperature, and / or the temperature of vehicle components. Furthermore, these parameters may change over time due to the operation of one or more blowers and / or the changing environment inside and / or outside the vehicle. In particular, the present disclosure relates to heat exchanges that originate from or ultimately travel to the occupant's body. In this way, thermal comfort may be provided to the occupant. In Huizenga et al., "A model for evaluating human physiology and comfort in complex thermal environments" ( A model ofhumanphysiology and comfortfor assessing complex thermal environments, An exemplary model of heat transfer relative to a human body in a transient, inhomogeneous environment is discussed in [1].

[0063] Dynamic estimation can be based on principles of physics. One or more heat transfer rates can be calculated, and the surface temperature can be estimated based on the heat transfer rate. The heat transfer rate between two media can generally be based on the temperature difference between the two media, the surface area over which heat transfer is occurring, one or more thermal resistances, or any combination thereof.

[0064] The disclosed method can estimate the temperature of a surface and continuously update this temperature estimate. Thus, the disclosed method can adapt to fluctuating ambient cabin conditions. Ambient cabin conditions can refer to the volume of air within the vehicle's cabin, such as the volume of air surrounding an occupant. The disclosed method can adapt in real time, providing continuous thermal comfort to the occupant.

[0065] The present disclosure provides a unique method that can rely on input from existing sensors that measure air temperature, sensors that detect the presence of occupants, any other existing sensors in the vehicle, or any combination thereof. The temperature sensors can include negative temperature coefficient (NTC) resistors, resistance temperature detectors (RTDs), thermocouples, semiconductor-type sensors, or any combination thereof. Thus, the method of the present disclosure may not require the temperature sensor to be located on or near the surface providing the airflow.

[0066] Non-limiting examples of occupancy sensors are described in U.S. Patent No. 7,205,902 B2 (describing sensors for use in the event of air bag activation), which is incorporated herein by reference for all purposes. Non-limiting examples of occupancy sensors that detect contact by an occupant with a vehicle component (e.g., a steering wheel or shift lever) are described in U.S. Patent No. 9,266,454 B2 (describing, for example, capacitive sensors, pressure sensors, etc.), which is incorporated herein by reference for all purposes.

[0067] Compared to conventional methods and systems, dynamic estimation can be based on a relatively small set of predetermined values. These values can include thermal resistance, heat capacity, surface area, the ratio of occupied surface area to unoccupied surface area, or any combination thereof. These values are non-limiting and other values can be implemented by the present disclosure. These values can be stored in a memory storage medium (e.g., a non-transitory memory storage medium).

[0068] One or more heat transfer rates can be dynamically estimated based on one or more of the aforementioned inputs. The heat transfer rates can include heat transfer rates between cabin air and a surface, between an occupant and a surface, between a material layer (e.g., a spacer layer) and a surface, between one or more air distribution devices and a material layer, between convective air and one or more material layers, between convective air and a trim layer, between a first material layer and a second material layer, or any combination thereof. These heat transfer rates are non-limiting and other heat transfer rates can be achieved using the present disclosure.

[0069] The dynamic estimation can employ one or more lookup tables, transfer functions, equations, or any combination thereof. Preferably, the dynamic estimation can be determined by one or more equations and / or transfer functions that characterize the physical principles of heat transfer between media. The equations and / or transfer functions can be input by sensors, calculations from previous program cycles, predetermined values (e.g., thermal resistance, heat capacity, cycle time, and surface area), or any combination thereof. Sensor input can be obtained in real time. Previous program calculations and / or predetermined values can be obtained from a memory storage medium (e.g., a non-transitory memory storage medium).

[0070] The disclosed method can bridge the gap between analytical theory and practical application. In this regard, some approximations and / or assumptions can be made about the real-life operation of the blower to complement the analytical theory. To this end, the concept of lumped capacitance can be employed. That is, a three-dimensional solid object experiencing a varying thermal environment can be assumed to be at a uniform bulk temperature, thereby ignoring temperature gradients throughout the thickness of the object.

[0071] Parameters including thermal resistance, heat capacity, and surface area may be predetermined. The parameters may be measured. The parameters may be stored in a memory storage medium (e.g., a non-transitory storage medium). The parameters may be provided in a lookup table. The parameters may be unique for different materials, layer thicknesses, and the like. Thus, different makes, models, and vehicle types having different vehicle component builds may be associated with different parameters.

[0072] Parameters, including thermal resistance, thermal capacitance, and surface area, can be adjusted to achieve a dynamic temperature estimate that matches the actual temperature of the component. In this regard, calibration can involve performing the method in a controlled environment with a sensor that measures the actual temperature of the seat component, so that the dynamically estimated temperature can be compared to the measured temperature. Thus, one or more values can be adjusted to achieve a dynamic temperature estimate that matches the measured temperature.

[0073] As referred to herein, estimation can mean the calculation of a parameter, with the understanding that the result of such calculation may not correspond exactly to the actual value (e.g., the temperature of a surface). Thus, the result of such calculation may be an estimate of the actual value. The methods of the present disclosure can provide an estimate that deviates from the actual value by about 10% or less, more preferably 5% or less, or even more preferably 1% or less.

[0074] Dynamic as referred to herein may mean that the estimation is reactive to changing conditions (e.g., cabin temperature, occupancy status, and the like). That is, as temperatures are dynamically estimated, they are used in subsequent program cycles to make further dynamic temperature estimates.

[0075] Any calculation, dynamic estimation, storage, transmission and / or acquisition steps described herein can be performed by one or more controllers. The controller can include one or more dedicated effector controllers, vehicle controllers, or both. Calculations and dynamic estimations can be performed by one controller or distributed among multiple controllers. Any predetermined value or input can be stored locally on the controller and / or remotely from the controller. Any input calculated or estimated from a previous program cycle can be stored locally on the controller and / or remotely from the controller. Any input from one or more previous program cycles can be temporarily stored on the controller and / or remotely from the controller. Any calculated or estimated input from one or more previous program cycles can be replaced or updated by calculated or estimated input from the current program cycle. The foregoing applies to all embodiments.

[0076] Any communication or transmission between the various controllers, sensors, and / or other devices described herein may be via a local interconnect network (LIN) bus. Communication or transmission may occur from a sensor to a controller or from a controller to another controller. By way of example and not limitation, an occupancy sensor may transmit an occupancy status to a vehicle controller, and the vehicle controller may then transmit an occupancy signal to a dedicated effector controller. The foregoing applies to all embodiments.

[0077] As used herein, a vehicle may be any automobile, recreational vehicle, marine vessel, aircraft, or the like, or any combination thereof. While this disclosure discusses convective heat transfer in vehicle seats, the teachings herein may be applicable to any object that functions by convective heat transfer. By way of example, the teachings herein may be applied to furniture (e.g., chairs and beds), buildings, or the like, or any combination thereof.

[0078] Dynamic estimation of surface temperature

[0079] The method may include dynamically estimating the surface temperature (T est The surface temperature can be dynamically estimated based on the heat transfer rate of the trimming layer to or from one or more surrounding media. The surface temperature can be dynamically estimated based on the heat transfer rate between the material layer and the trimming layer. Heat transfer rate between cabin air and trim layer Heat transfer rate between occupant and trim layer Heat transfer rate between any number of other sources and the trimming layer or any combination thereof to dynamically estimate.

[0080] Temperature change of the finishing layer per unit time It can be determined based on the aforementioned heat transfer rate and the heat capacity (C) of the trimming layer.

[0081] Using a known program cycle time (t) (e.g., 1 second or less, 50 milliseconds or less, 30 milliseconds or less, or even 10 milliseconds or less), the temperature change (ΔT) over the cycle duration can be determined based on the temperature change of the trimmed layer per unit time according to the following equation.

[0082]

[0083] The temperature change can be added to the initial or previous surface temperature (T (n-1) ) to obtain the estimated surface temperature (T est ).

[0084] Eq.BT (n-1) +ΔT=T est

[0085] Before startup, an initial surface temperature can be used. This initial surface temperature can be assumed to be equal to the temperature sensed by local sensors at startup. This means that the cabin air and vehicle component temperatures can be normalized after the vehicle has been exposed to the environment for a period of time before startup. Local sensors can include sensors located within the cabin, on heating elements, in exhaust vents, or elsewhere. Any sensor within the vehicle can provide the startup temperature.

[0086] After startup, a previous surface temperature may be used. The previous surface temperature may be an estimated surface temperature from a previous program cycle.

[0087] The following provides a method for determining the heat transfer rate between the material layer and the trim layer. Heat transfer rate between cabin air and trim layer Heat transfer rate between occupant and trim layer and the heat transfer rate between any number of other media method.

[0088] Occupancy detection

[0089] The method may include obtaining an occupancy state of the seat. The occupancy state may indicate whether the seat is occupied by an occupant. The occupancy state may be provided by the vehicle using existing sensors, such as occupancy sensors used for airbag operation. The occupancy state may be related to thermal resistance and / or the surface area through which heat transfer occurs.

[0090] An occupied seat can cause compression of the trim layer, one or more material layers, the fluid distribution device, or any combination thereof. Compression can affect the thermal resistance discussed herein because the thickness through which heat travels is different in a compressed seat than in an uncompressed seat. Compression can also affect the surface area discussed herein.

[0091] The method of the present disclosure can be performed on unoccupied seats. The method of the present disclosure can be performed regardless of whether an ON command is provided to one or more blowers. In this way, the initial surface temperature can be known and is known any time an occupant enters the vehicle and / or contacts the seat. This can be useful for pre-conditioned vehicles (e.g., vehicles equipped with automatic start) and / or for passengers entering the vehicle at some point after start-up.

[0092] The heat transfer rate between the convective air and the material layer

[0093] The method may include determining the heat transfer rate between the convective air and the material layer

[0094] Convection air can flow through the air distribution device, enter the ventilation holes formed in the material layer and / or its pores, and reach the finishing layer.When the convection air travels through the ventilation holes formed in the material layer, it can exchange heat with the material layer.

[0095] Convective air can flow through groove lines in the seat. The groove lines can be defined between adjacent portions of the seat. By way of example, air can flow between a fluid distribution device and a spacer layer, between a spacer layer and a finishing layer, or the like. The surface areas for convective heat transfer discussed herein can be calibrated to account for the groove lines. That is, the surface areas employed in the present method can be adjusted to account for the groove lines.

[0096] The heat transfer rate can be expressed as the temperature of the convective air (T conv ), the temperature of the material layer (T material ), the surface area (A) of the material layer with which the convective air is thermally connected, the thermal resistance (R) of the material layer, or any combination thereof.

[0097] The heat transfer rate can be determined by the following equation.

[0098]

[0099] The convective air temperature may be provided by one or more local sensors located in the cabin of the vehicle. The convective air temperature may be assumed to be equal to the cabin air temperature. The convective air temperature may be provided by one or more sensors located in the blower, in a conduit extending between the blower and the fluid distribution device, in the fluid distribution device, or any combination thereof.

[0100] The temperature of the material layer can be assumed to be equal to the temperature sensed by the local sensor at startup. In other words, the temperature of the material layer can be assumed to be equal to the cabin ambient temperature. After startup, the temperature of the material layer can be obtained from the previous program cycle. The temperature of the material layer determined by the program cycle of the present method is discussed further below.

[0101] The surface area may include the surface area of the material layer with which the convective air is in thermal communication. This may include the collective surface area of the vents extending through the material layer, the surface area of the pores of the material layer, the surface area of the material layer contacted by the fluid distribution device, or any combination thereof. Additionally, the surface area may take into account the groove lines within the seat. The surface area of the material layer may be indicative of whether the seat is occupied (A occ ) or unoccupied (A unocc ). That is, compression of the material layer can affect the surface area with which convective air is in thermal communication.

[0102] The thermal resistance of the material layer can be used to characterize whether the seat is occupied (R occ ) or unoccupied (R unocc ). That is, the compression of a material layer can affect its thermal resistance.

[0103] Heat transfer rate between the material layer and the finishing layer

[0104] The method may include determining the heat transfer rate between the material layer and the trim layer

[0105] The temperature of the material layer can be affected by convective air flowing through the material layer. The material layer can exchange heat with the finishing layer by conduction, convection, or both.

[0106] The heat transfer rate can be the temperature of the material layer (T material ), the temperature of the finishing layer (T trim ), the surface area (A) through which the material layer is thermally connected to the trim layer, the thermal resistance (R) of the trim layer, or any combination thereof.

[0107] The heat transfer rate can be determined by the following equation.

[0108]

[0109] The temperature of the trim layer can be assumed to be equal to the temperature sensed by the local sensor at startup. In other words, the temperature of the trim layer can be assumed to be equal to the temperature of the cabin environment. After startup, the temperature of the trim layer can be obtained from the previous program cycle. The temperature of the trim layer can be determined through the program cycles of the present method.

[0110] The temperature of the material layer may be determined as discussed above.

[0111] The surface area may include the surface area of the trim layer with which the material layer is in thermal communication.

[0112] The thermal resistance of the trim layer can be used to characterize whether the seat is occupied (R occ ) or unoccupied (R unocc ). That is, compression of the trim layer can affect its thermal resistance.

[0113] Dynamic estimation of material layer temperature

[0114] Based on the aforementioned heat transfer rate relative to the material layer, the temperature of the material layer (T material ).

[0115] The temperature of the material layer may be the initial or previous temperature (T material(n-1) ), the sum of the heat transfer rates relative to the material layer, the heat capacity of the material layer (C), and the program cycle time (Δt). The temperature of the material layer can be dynamically estimated using the following equation.

[0116]

[0117] The initial temperature of the material layer may refer to the temperature sensed by the local sensor at startup, as discussed above. The previous temperature of the material layer may refer to the temperature from a previous program cycle, as discussed above.

[0118] Heat transfer rate between the environment and / or occupant and the trim layer

[0119] The method may include calculating the heat transfer rate between the cabin air and the trim layer

[0120] The method may include obtaining an occupancy state, as described above. If the seat is unoccupied, a heat transfer rate between the cabin air and the trim layer may be calculated. If the seat is occupied, a heat transfer rate between the cabin air and the trim layer, and a heat transfer rate between the occupant's skin and the trim layer may be calculated. These two heat transfer rates relative to the trim layer may be determined due to different portions of the seat being in thermal communication with each other. As an example, when an occupant is seated, the area between the occupant's legs and the area around the outer edge of the seat may be in thermal communication with the cabin air.

[0121] The heat transfer rate relative to the cabin air can be the cabin temperature (T cab ), the temperature of the finishing layer (T trim ), the thermal resistance to free convection air (R), the surface area through which heat transfer occurs (A), or any combination thereof. The heat transfer rate relative to the cabin air can be determined by the following equation.

[0122]

[0123] The heat transfer rate relative to the occupant can be the temperature of the occupant's skin (T skin ), the temperature of the finishing layer (T trim ), clothing thermal resistance (R clo ) and skin thermal resistance (R skin ), the surface area (A) through which heat transfer occurs, or any combination thereof. The heat transfer rate relative to the occupant can be determined by the following equation.

[0124]

[0125] It will be appreciated that one or both heat transfer rates may be determined based on the seat's occupancy state. Furthermore, the surface area may be selected based on the seat's occupancy state. Given a known seat surface area, one or more first portions of the surface area may be in thermal communication with the cabin air and one or more second portions of the surface area may be in thermal communication with the occupant.

[0126] The cabin air temperature may be provided by a local sensor.

[0127] Skin temperature can be set to a fixed value (e.g., a value within the normal human skin temperature range of 33°C to 37°C). Skin temperature can be modeled as a function of trim temperature, cabin air temperature, blower operation, or any combination thereof. Skin temperature can be determined by one or more sensors.

[0128] The trim temperature may be assumed to be equal to the temperature sensed by the local sensor at vehicle startup.The trim temperature may be provided by a dynamic estimation after vehicle startup as taught herein.

[0129] The thermal resistance of clothing may depend on the geographic region, the season, the part of the body being conditioned, or any combination thereof. The foregoing may inform assumptions about the clothing worn by the occupant. In regions with temperate climates, heavier clothing (e.g., jackets) may be worn in the cooler months, and lighter clothing (e.g., t-shirts) may be worn in the warmer months. In regions with tropical climates, lighter clothing may be worn year-round. Furthermore, the clothing worn may depend on the part of the body being conditioned. As an example, pants worn in the cooler months may have a thermal resistance that is roughly equivalent (e.g., 10% deviation or less) to shorts worn in the warmer months. On the other hand, if the torso is being conditioned, a jacket worn in the cooler months may have a greater thermal resistance than a shirt worn in the warmer months.

[0130] Blower control

[0131] The dynamically estimated trim surface temperature may be employed in the operation of one or more blowers.Based on the dynamic estimate of the surface temperature, the duty cycle and / or ON / OFF command of the blowers may be controlled.

[0132] One or more blowers can be programmed to operate in push mode or pull mode. In push mode, air is first drawn into the blower and pushed to the surface. In pull mode, air is first drawn from the surface into the seat and pulled to the blower.

[0133] The air drawn into the blower in push mode may be drawn from under the seat and / or near the underside of the seat. The air pulled toward the blower in pull mode may be drawn from the surface of the trim and / or near the surface of the trim.

[0134] Seat ventilation may function to draw heat from the seat, provide cooling to the occupant, draw moisture from the occupant, force air toward the occupant, or any combination thereof.

[0135] The blower can be operated to achieve a steady state of surface temperature. In this regard, heat absorbed by the seat from an occupant and / or when immersed in a hot environment can be drawn away from the seat. The dynamically estimated surface temperature can be monitored, and when a steady state is achieved, the blower can be turned off or the airflow rate can be adjusted downward between set points. If the dynamically estimated surface temperature exceeds a threshold, the blower can be adjusted upward between set points.

[0136] The blower can be operated to provide a cooling sensation to the occupant. In this regard, the convective air can draw away heat from the occupant's dry skin or draw away moisture from the occupant. A relative humidity sensor can be provided in the seat to detect humidity.

[0137] The cabin air temperature can be compared to low and / or high thresholds to determine whether the blower should be shut off or at least adjusted downward. When convective air is ventilated through the seats, the cabin air temperature can be uncomfortable for the occupants. This can occur in vehicles exposed to freezing or near-freezing temperatures as well as in vehicles exposed to high temperatures.

[0138] Figure 1A seat 10 is shown. The seat 10 includes a layered construction of a trim layer 12, a spacer layer 14, and a fluid distribution device 16. A blower 18 is located on the underside of the seat 10, although the present teachings also contemplate that the blower 18 may be located to the side of or within the fluid distribution device 16 and fluidly connected to the fluid distribution device 16 with a conduit 20 disposed therebetween. The present teachings contemplate that the conduit 20 may or may not be present and, if not present, the blower 18 may be directly connected to the fluid distribution device 16. Furthermore, the conduit 20 may extend in length to accommodate various positions of the blower 18 relative to the seat 10. In this regard, the conduit 20 may include one or more elbows.

[0139] Figure 1 however, the present teachings contemplate that the same or even similar arrangement may be provided in the back portion or any other portion of the seat 10. The seat 10 may be provided with the illustrated apparatus in both the seat portion and the back portion, and optionally in any other portion of the seat 10.

[0140] Air from the underside of the seat 10 can be drawn into the inlet of the blower 18 and exhausted through the outlet of the blower 18, ultimately entering and filling the fluid distribution device 16. The air travels through a plurality of channels 22 formed in the spacer layer 14 to the trim layer 12, thereby conditioning the occupant 24 who contacts the surface 26 of the trim layer 12. This manner of airflow can be referred to as a push mode (i.e., the air is pushed toward the occupant by the blower), with one exemplary path being shown in phantom as progressing through the seat 10. The present teachings contemplate operation in the opposite manner, referred to as a pull mode (i.e., the air is pulled away from the occupant by the blower).

[0141] The trim layer 12 is in thermal communication with the occupant 24 and / or the ambient air ("ambient") proximate the trim layer 12. In one aspect, the seat 10 can be unoccupied, and in this regard the trim layer 12 is in thermal communication only with the ambient air. In another aspect, the seat 10 can be occupied, and in this regard, a portion of the trim layer 12 is in thermal communication with the occupant 24, while another portion of the trim layer 12 is in thermal communication with the ambient air (e.g., in the area between the occupant's legs, in the seat cushion area, and the like).

[0142] The heat transfer rates to the trim layer 12 are illustrated and include a heat transfer rate 28 relative to the environment, a heat transfer rate 30 relative to the occupant, a heat transfer rate 32 relative to the spacer layer, and a heat transfer rate 34 relative to the convective air. Furthermore, the fluid distribution device 16 and the spacer layer 14 are in thermal communication with each other, so there is heat transfer 36 relative to the fluid distribution device. As shown, the heat transfer rates are all directed toward the trim layer 12, although the present teachings also contemplate heat transfer rates directed in the opposite direction, depending on the relative temperatures of the two thermally connected media.

[0143] The present method dynamically estimates the temperature of a thermal medium (e.g., a trim layer, a spacer layer, a fluid distribution device, etc.) based on one or more calculated heat transfer rates to and / or from the thermal medium. Ultimately, the temperature of the surface contacted by the occupant can be dynamically estimated and utilized in the control of the blower. In this regard, a temperature sensor 38 and, optionally, a relative humidity sensor 40 can be employed. As shown, the temperature sensor 38 is located in the blower 18, and the relative humidity sensor is located in the spacer layer 14, however, the present teachings contemplate that the sensors can be located anywhere practicable, consistent with the teachings of the present invention.

[0144] Figure 2 is a schematic diagram of a system for performing the methods of the present teachings. The system includes a controller 42 that receives an input 44 from a blower, an input 46 from a temperature sensor, and an input 48 from a relative humidity sensor. Based on the input 46 from the temperature sensor, a heat transfer rate estimator module 50 can output a heat transfer rate. Based on the heat transfer rate and optionally one or more other heat transfer rates, a temperature estimator module 50 can output a temperature.

[0145] The system includes a human machine interface ("HMI") 54 that an occupant can actuate to provide user input by selecting an operating mode (e.g., ON / OFF) and / or set points such as a temperature set point and / or an airflow rate set point (e.g., levels 1, 2, and 3) ("user input"). The user input can be signaled directly to the controller 42 and / or to any vehicle controller, such as an engine control unit ("ECU") 56. The ECU 56 processes the user input to generate a controller input and provides the controller input to the controller 42.

[0146] Controller 42 includes a control module 58 that functions to control the duty cycle and / or ON / OFF pattern of blower 44. The duty cycle is a function of user input and / or controller input, relative humidity, one or more temperature estimates, or any combination thereof.

[0147] Figure 3 is a flow chart of a method of the present teachings. Transitions between method steps are represented by solid black arrows, and inputs used in calculations are represented by dashed arrows.

[0148] The method includes determining an occupancy state of the seat, which affects selection of parameters including thermal resistance, thermal capacity, and surface area.

[0149] The method includes determining a heat transfer rate between a convective air flow and a spacer layer. The temperature of the convective air is provided by a local sensor located within the vehicle cabin. The temperature of the spacer layer is provided by a dynamic estimate from a previous program cycle. It should be understood that the temperature of the spacer layer may also be provided by a local sensor prior to startup, as discussed herein.

[0150] The method includes determining a heat transfer rate between a spacer layer and a trim layer. Prior to startup, the temperatures of the spacer layer and the trim layer are provided by local sensors positioned within the vehicle's cabin. The temperatures of the spacer layer and the trim layer are provided by dynamic estimates from a previous program cycle.

[0151] The method includes determining the heat transfer rate between the occupant and the trim layer and / or the cabin environment and the trim layer. At startup, the temperature of the trim layer is provided by a local sensor. After startup, the temperature of the trim layer is provided by a dynamic estimate from the previous program cycle.

[0152] The method includes dynamically estimating the temperature of the material layer and the temperature of the trim layer based on the associated heat transfer rates. The dynamically estimated temperatures can be used in subsequent program cycles.

[0153] Multiple elements or steps may be provided by a single integrated element or step. Alternatively, a single element or step may be divided into separate multiple elements or steps.

[0154] The disclosure of "a" or "an" describing an element or step is not intended to exclude additional elements or steps.

[0155] The method may include one or more steps described herein. Some of the steps may be repeated, removed or eliminated, rearranged relative to other steps, combined into one or more steps, separated into two or more steps, or a combination thereof.

[0156] The flow diagrams described herein do not imply a fixed order to the steps, and embodiments of the invention may be practiced in any order practicable unless otherwise indicated herein.

[0157] Although in this article, term first, second, third etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be restricted by these terms.These terms can be used to distinguish an element, component, region, layer or part from another region, layer or part.Terms such as "first", "second" and other numerical terms do not imply sequence or order when used in this article, unless clearly indicated by context.Therefore, the first element, component, region, layer or part discussed below can be referred to as the second element, component, region, layer or part without departing from teaching.

[0158] Spatially relative terms such as "in," "out," "below," "beneath," "down," "above," "above," and the like may be used herein for ease of description to describe the relationship of one element or feature to another element or feature as shown in the accompanying drawings. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the figures is flipped, elements described as being "below" or "below" other elements or features would then be oriented as being "above" the other elements or features. Thus, the example term "below" can encompass both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly.

[0159] Unless otherwise indicated, all ranges include both the endpoints and all numbers between the endpoints. The use of "about" or "approximately" in connection with a range applies to both ends of the range. Thus, "about 20 to 30" is intended to encompass "about 20 to about 30," including at least the specified endpoints.

[0160] The term "consisting essentially of" used to describe a combination shall include the identified elements, ingredients, components, or steps, and such other elements, ingredients, components, or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms "comprising" or "including" herein to describe a combination of elements, ingredients, components, or steps also contemplates embodiments that consist essentially of the elements, ingredients, components, or steps.

[0161] Reference Mark

[0162] 10 seats

[0163] 12 finishing layers

[0164] 14 spacer layers

[0165] 16Fluid distribution equipment

[0166] 18 Blower

[0167] 20 catheters

[0168] 22 channels

[0169] 24 passengers

[0170] 26 surfaces

[0171] 28 Heat transfer relative to the environment

[0172] 30 Heat transfer relative to the occupants

[0173] 32 Heat transfer relative to the spacer layer

[0174] 34 Heat transfer relative to convection air

[0175] 36 Heat Transfer with Respect to Fluid Distribution Equipment

[0176] 38 temperature sensors

[0177] 40 relative humidity sensors

[0178] 42 controllers

[0179] 44 Blower

[0180] 46 temperature sensors

[0181] 48 relative humidity sensor

[0182] 50 Heat Transfer Rate Estimator Module

[0183] 52 Temperature Estimator Module

[0184] 54 Human-machine interface

[0185] 56 Engine Control Unit

[0186] 58 control module

Claims

1. A method for estimating a surface temperature of a ventilated seat, the method comprising: determining a rate of heat transfer to or from the layer of material based on a temperature imparted to the layer of material by convective air; estimating a temperature of the layer of material based on a rate of heat transfer to or from the layer of material; determining a rate of heat transfer to or from the trim layer based on a temperature of the layer of material applied to the trim layer; calculating a rate of change of the surface temperature based on a rate of heat transfer to or from the trim layer; as well as The estimated surface temperature of the trim layer from a previous program cycle is updated based on the rate of change of the surface temperature and the estimated surface temperature of the trim layer from the previous program cycle.

2. The method according to claim 1, wherein The convective air flows through one or more ventilation holes formed in the material layer and / or pores in the material layer.

3. The method according to claim 1 or claim 2, wherein: The convection air is extracted from the cabin of the vehicle.

4. A method according to any one of the preceding claims, wherein The convective air is not thermally conditioned by heating and / or cooling equipment.

5. A method according to any one of the preceding claims, wherein The material layer is a spacer layer disposed between the trim layer and the fluid distribution device.

6. A method according to any one of the preceding claims, wherein The method also includes determining a second heat transfer rate to or from the trim layer based on a second temperature applied to the trim layer.

7. The method according to claim 6, wherein: The second temperature is applied by cabin air; optionally, wherein the cabin air is located above the trim layer.

8. A method according to any one of the preceding claims, wherein The method also includes determining a third heat transfer rate to or from the trim layer based on a third temperature applied to the trim layer.

9. The method according to claim 8, wherein The third temperature is applied by an occupant.

10. A method according to any one of the preceding claims, wherein The rate of change of the surface temperature is additionally based on the second heat transfer rate and / or the third heat transfer rate.

11. The method according to claim 10, wherein: The method also includes determining an occupancy status of the ventilated seat.

12. The method according to claim 11, wherein For an occupied seat, the rate of change of the surface temperature is additionally based on the second heat transfer rate and the third heat transfer rate.

13. The method according to claim 11 or claim 12, wherein: For unoccupied seats, the rate of change of the surface temperature is additionally based on the second heat transfer rate.

14. A method according to any one of the preceding claims, wherein The heat transfer rate to or from the material layer and the trim layer is affected by the thermal resistance of the material layer and the thermal resistance of the trim layer, respectively; and wherein the thermal resistance of the material layer and the thermal resistance of the trim layer are selected based on whether the ventilated seat is occupied.

15. A method according to any one of the preceding claims, wherein The rate of heat transfer to or from the layer of material is affected by a surface area to which the first temperature is applied; and wherein the surface area is selected based on whether the ventilated seat is occupied.

16. A method according to any one of the preceding claims, wherein The temperature estimated for the material layer and / or the rate of change of the surface temperature is based on one or more additional heat transfer rates.

17. The method according to claim 16, wherein The one or more additional heat transfer rates relative to the layer of material include a heat transfer rate between a fluid distribution device and the layer of material.

18. A method according to any one of the preceding claims, wherein The first temperature is sensed by a sensor local to a cabin of a vehicle in which the ventilated seat is located.

19. The method according to any one of the preceding claims, further comprising controlling the blower, comprising: receiving the surface temperature; Receiving cabin air temperature; optionally receiving relative humidity; as well as A duty cycle of the blower is adjusted based on the surface temperature, the cabin air temperature, the relative humidity, or any combination thereof.

20. A system for performing the method according to claim 19, the system comprising: Blowers operating in push or pull mode; a fluid dispensing device (e.g., in the form of a bag), a portion of which is oriented toward the air permeable seat surface; a temperature sensor (e.g., onboard the blower); and A relative humidity sensor (eg, located proximate to the seating surface).

Images