Personalized air conditioning settings

Abstract

Device in a transport vehicle occupied by one person (42) in a passenger compartment (20), comprising: a skin temperature sensor to measure the actual skin temperature (43) of the person (42); a passenger compartment temperature sensor (26) for measuring an actual passenger compartment temperature (44) of the ambient air in the passenger compartment (20); an HVAC system to provide a heated and cooled airflow into the passenger compartment (20); a control module that includes means to store a target passenger compartment temperature and to control the HVAC system according to a first error between the target passenger compartment temperature and a passenger compartment temperature averaged according to a first time constant (44) and a personalization module (40) that includes means to provide a recommended target skin temperature, to choose between accepting the recommended target skin temperature and entering a desired target skin temperature, to save the selected target skin temperature to determine a compensation to be applied to the target passenger compartment temperature, the value of which depends on the first error and on a second error between the selected target skin temperature and a skin temperature averaged according to a second time constant, to determine a modified target passenger compartment temperature and to control the HVAC system according to the modified target passenger compartment temperature, wherein the second time constant is longer than the first time constant.

Description

[0001] The present invention relates generally to heating, ventilation and air conditioning (HVAC) systems for transport vehicles and in particular to the personalized control of an HVAC system based on the skin temperature of a vehicle occupant or driver of the vehicle.

[0002] HVAC systems control the climate in transport vehicles, such as automobiles, to maintain the comfort of the vehicle occupants. Typically, a fan blows air through heat exchangers and delivers conditioned air to various points within the passenger compartment. Warm air can be supplied by a heating element, which, for example, extracts heat from the coolant flowing in an internal combustion engine. Cool air can be drawn from a conventional air conditioning system with a motor-driven compressor and an evaporator.

[0003] The simplest climate control systems in vehicles allow the vehicle occupant to directly control the heating or cooling intensity, the fan speed, and the relative amount of air flowing to different vents. To do this, the user must continuously monitor and adjust the climate control settings to maintain comfort.

[0004] Automatic temperature control systems have also been introduced, in which a feedback control system monitors the ambient air temperature in the passenger compartment and automatically adjusts the fan speed and the operation of the heating element or air conditioning to maintain a desired temperature setting. Some vehicles have multiple zones with separate automatic temperature control and individual target temperature settings for each zone.

[0005] The HVAC systems described above only indirectly controlled the actual skin temperature of a vehicle occupant. Since skin temperature is a better indicator of actual occupant comfort, systems for regulating HVAC operation based on occupant skin temperature have been investigated. However, the thermodynamic environment within a vehicle interior and the relationships between different HVAC system settings and their resulting effects on the skin temperature of various occupants are complex. Therefore, earlier systems were relatively complicated and not cost-effective.

[0006] US 2004 / 0089006A1 and US 2005 / 0103488A1 each disclose a device in a passenger compartment of a single-occupant transportation vehicle, comprising: a skin temperature sensor for measuring the actual skin temperature of the person; a passenger compartment temperature sensor for measuring the actual ambient air temperature in the passenger compartment; an HVAC system for providing a heated and cooled airflow to the passenger compartment; a control module that stores a target passenger compartment temperature, wherein the control module controls the HVAC system according to a first error between the target passenger compartment temperature and the actual passenger compartment temperature, wherein the actual passenger compartment temperature is filtered according to a first time constant;and a personalization module that stores a target skin temperature, wherein the personalization module determines an adjustment to be applied to the target passenger compartment temperature according to a second error between the target skin temperature and the actual skin temperature, wherein the actual skin temperature is filtered according to a second time constant that is longer than the first time constant. The ECU units of the two documents each have all the necessary sensors / signals and memory units to be programmed to perform the functions of the controller module and the personalization module.

[0007] Other publications relevant to the state of the art are US 5 682 329 A, US 2010 / 0 106 365 A1 and DE 10 2007 050 375 A1.

[0008] The present invention provides a device with the features of the independent claim. Advantageous embodiments of the invention are described in the dependent claims. It enables personalized climate control tailored to a vehicle occupant, for example, the driver. Instead of directly attempting to regulate the occupant's skin temperature, certain adjustments are made to the target temperature of the passenger compartment to control the HVAC system, so that its operation is only partially controlled in response to skin (i.e., body) temperature. The adjustments for ensuring stable system operation are subject to certain limitations.

[0009] In one aspect of the invention, a device is provided in a transport vehicle, operated by a driver in a passenger compartment, comprising a skin temperature sensor for measuring the driver's actual skin temperature and a passenger compartment sensor for measuring the actual ambient air temperature in the passenger compartment. A HVAC system provides a heated and cooled airflow to the passenger compartment. A control module stores a target passenger compartment temperature, and the control module controls the HVAC system according to a first error between the target passenger compartment temperature and the actual passenger compartment temperature. The actual passenger compartment temperature is filtered according to a first time constant.A personalization module stores a target skin temperature, from which the personalization module calculates an adjustment to the target passenger compartment temperature based on a second error between the target skin temperature and the actual skin temperature. The actual skin temperature is filtered according to a second time constant that is longer than the first time constant. Fig. Figure 1 is a block diagram of an HVAC system with automatic temperature control. Fig. Figure 2 is a schematic and block diagram of parts of an HVAC system and controller according to the invention. Fig. Figure 3 is a block diagram that illustrates the present invention in more detail. Fig. Figure 4 is a flowchart of a preferred method of the invention. Fig. Figure 5 is a graphical representation of a diagram for determining an amplification factor. Fig. Figure 6 shows a first embodiment of relative orientations of infrared sensors on a steering wheel directed towards a driver. Fig. Figure 7 is a graphical representation of sample temperature data. Fig. Figure 8 is a flowchart showing a preferred method for determining a person's skin temperature in a vehicle.

[0010] Referring to Fig. Figure 1 shows a prior art electronic automatic temperature control system (EATC 10) for climate control in a passenger compartment 11 of a transport vehicle. An EATC controller 12 receives ambient air temperature measurements from a sensor 13 located in the passenger compartment 11. Using feedback control, the EATC 10 determines the operation of a fan 14, a heating source 15, and a cooling source 16. The temperature measurement, heating, and cooling functions can be duplicated according to the zones in the passenger compartment 11 to implement a multi-zone climate control system as known in the prior art.

[0011] The present invention builds upon the EATC 10. Fig. 1. This feature adds a personalization function for adjusting the EATC temperature setpoint to improve the comfort of an individual occupant in a specific climate-controlled zone. The personalization function is provided "on demand." It can typically be selected whenever the occupant is alone in the vehicle or in a specific zone. In a transport vehicle, many journeys involve only a driver. During such times, modifying the operation of the EATC 10 to optimize driver comfort can be highly desirable, as it can also lead to energy savings.

[0012] A system according to the invention is in Fig. 2 shown in more detail. In a passenger compartment 20, a steering wheel 21 is located in front of a driver. A user interface 28, typically mounted on a dashboard, may include an information display 23, a control knob 24, and function keys 25. An ambient air temperature sensor 26 measures the passenger compartment temperature in the conventional manner. An external temperature sensor 27 may be mounted outside the passenger compartment to determine the temperature outside the vehicle. To obtain a temperature preview and / or as an alternative means of obtaining an outside temperature, a wireless communication system 30 and an antenna 31 are provided, as further described below.

[0013] To measure the driver's skin temperature, a pair of infrared sensors 32 and 33 are attached to the steering wheel 21. Heated or cooled airflow is supplied to the driver from various registers, including register 35.

[0014] A control device for carrying out the present invention is in Fig. Figure 3 shows in more detail. A driver personalization function is implemented as a personalization module 40, which works in conjunction with the automatic temperature control controller module. The personalization module 40 can be a software module running on the same electronic programmable microcontroller in the EATC system 22 or by a device in a separate box. A skin temperature target command is supplied to the EATC system 22 by the driver personalization function via a selector switch 41 (i.e., a driver-operated toggle switch to select between a conventionally provided zone setpoint temperature and a personalization mode using the skin temperature target command). As further described below, the driver personalization function provides a recommended target value for the driver's skin temperature.The personalization function is controlled by the driver 42, who uses the user interface 28 to switch the function on or off. If a personalized setting is desired, the driver 42 evaluates the recommended target value and then either adopts this temperature or enters a different temperature via the user interface 28.

[0015] The driver personalization function receives various temperature measurements, including skin temperature (43), interior (i.e., passenger compartment) ambient temperature (44), exterior ambient air temperature (45), and a temperature forecast (46). The temperature forecast (46) can correspond to upcoming exterior temperature conditions based on either 1) current or future temperature measurements at a destination to which the vehicle is being driven, or 2) a short-term temperature forecast for the immediate vicinity of the vehicle. This temperature forecast can be received from a remote service provider via a wireless communication system. Based on known models that relate various temperature conditions to a person's skin temperature and their personal comfort level, the personalization function derives a recommended target skin temperature based on known physical / perceptual models.

[0016] Using a from Fig. Based on the derived target skin temperature, the operation of the HVAC control system in a preferred embodiment is determined according to the above. Fig. The procedures shown in section 4 have been modified. In personalization mode, for optimizing climate control according to a vehicle occupant's skin temperature, improved feedback control is performed based on body temperature (i.e., skin temperature) and passenger compartment temperature. To ensure the stability of the feedback control system, the controller reacts more sensitively to changes in passenger compartment temperature than to changes in body temperature. Passenger compartment temperature measurements are therefore filtered in step 50 according to a first time constant. Skin temperature measurements are filtered in step 51 according to a second time constant, which is longer than the first. In step 52, the errors between the filtered (e.g., averaged) temperature measurements and their respective target temperatures are determined.Based on the magnitude of the errors, a tunable gain factor is determined in step 53 to calculate compensation applied to the target temperature in the passenger compartment. The passenger compartment target temperature is updated in step 54, and then the HVAC system continues conventional operation using the modified target value for feedback control of the passenger compartment temperature.

[0017] Signal processing and decision-making in Fig. Four steps can be performed as follows. The filtering of body temperature and passenger compartment temperature is carried out according to the following equations: CTk¯=αCTCTk−1¯+(1−αCT)CTk BTk¯=αBTBTk−1¯+(1−αBT)BTk where CT is the actual passenger compartment temperature, α CT the filter gain between 0 and 1, which defines the first time constant, BT the actual skin temperature, α BTThe filter amplifiers, which define the second time constant, and k are an index. The first error is determined according to a formula: CTerr(k)=CTtar(k)−CTk¯ where CT err The first error and CT tar The target passenger compartment temperature (i.e., the one used by EATC system 22 as the feedback target value) is determined. The second error is calculated according to a formula: BTerr(k)=BTtar(k)−BTk¯ where BT err the second error and BT tar The target skin temperature is determined. An updated target passenger compartment temperature (i.e., after incrementing the index k by one) is calculated according to a formula: CTtar(k)=CTtar(k−1)+K1BTerr(k) where K1 is the tunable gain factor for a normalized gain factor between 0 and 1. The size of BT erris applied when the tunable normalized K1 range is between -1 and 1, in order to provide appropriate directional compensation for the passenger compartment temperature.

[0018] A rule basis is provided for the value of the gain factor K1, which is intended to limit the amount of change at each iteration and prevent changes during times when the passenger compartment temperature error is greater than a threshold difference (e.g. 5°F).

[0019] One embodiment of the rule basis for the invention is a normalized surface diagram in Fig. Figure 5 shows the mapping of errors to a value of K1. Thus, a value for the gain factor K1 is represented as a three-dimensional surface map 60, which defines the value for K1 for different values ​​of the passenger compartment temperature error along axis 61, the body temperature error along axis 62, and the K1 value along axis 63. In this embodiment, the output of the passenger compartment temperature change for the normalized gain factor between -1 and 1 is determined according to the following formula: CTtar(k)=CTtar(k−1)+K1|BTerr(k)|

[0020] The values ​​for the passenger compartment temperature error and the body temperature error are shown with respect to a normalized scale between 1 and -1, representing thresholds within which the personalization function is permitted to operate. Near these thresholds, the value of K is zero to prevent the personalization function from operating. For example, at high values ​​of the passenger compartment temperature error, the value of K1 approaches zero along regions 64 and 65 of surface map 60. Similarly, when the body temperature error is near zero, surface map 60 is at a zero value, as shown in region 66. When the passenger compartment temperature error is near zero, but the body temperature error is between the upper and lower thresholds, increasingly higher values ​​of the gain factor K1 are shown, as shown in regions 67 and 68.

[0021] Instead of the diagram, the controller can alternatively use a numerical ratio to determine the gain factor. Such a ratio can generally be expressed as K1 = f(CT). err , BT err Suitable equations defining this function are constructed according to the desired properties for a specific vehicle, but would have a gain factor similar to that in Fig. Figure 5 shows the result. Using the resulting value K1 from such equations, a regression delta_CT is then calculated. tar calculated as follows: delta_CTtar(k)=K1BTerr(k) for normalized gain factors between 0 and 1, and delta_CTtar(k)=K1|BTerr(k)| with a normalized K1 range between -1 and 1. To ensure that the personalization function does not affect the overall performance of the temperature control system and to guarantee stable operation, the compensation is further modified according to the following limits: delta_CTtar={0if{|CTerr|>δthres0if{|BTerr|>αthresdelta_CTtarif{(βthres<|CTerr|≤δthres) and{(λthres<|BTerr|≤αthres)0otherwise where δ thres an upper limit for CT err , β thres a lower limit for CT err , α thres a ceiling for BT err , and λ thres a lower limit for BT err The thresholds prevent the introduction of modifications by the personalization function if one of the errors is too small or too large, thus ensuring stability and avoiding unwanted interactions.

[0022] For robust skin temperature measurements, as in Fig. Figure 6 shows the detection regions of the infrared sensors mounted on the steering wheel. The face of a person 70 in a specific seat (for example, the driver's seat) is located in a position relative to the infrared sensors 72 and 74 on the steering wheel 71, depending on their height or posture. For positions other than the driver's seat, the infrared sensors 72 and 74 can be mounted on other suitable surfaces, such as a dashboard or headliner, where they are directed towards the area where the occupant's face is expected to be. The infrared sensor 72 has a detection region 73 and the infrared sensor 74 has a detection region 75, which are directed at slightly different heights and spaced laterally to the right and left sides of the person 70's face, respectively.The use of detection regions with slightly different heights and slightly different lateral regions increases the probability that at least one temperature measurement will match the face of a driver of unknown height.

[0023] The temperature measurements are evaluated to ensure that the sensor receiving the better skin temperature reading is used as described in the instructions. Fig. Figure 7 is used. Line 77 represents an ambient air temperature measurement as obtained in the passenger compartment. Line 78 represents temperature measurements from one infrared sensor, and line 79 represents temperature measurements from the other infrared sensor. Essentially, during all relevant thermal conditions that may prevail in the vehicle, the infrared sensor, which does not accurately measure skin temperature, will accurately track the ambient air temperature, as shown by the close correlation between lines 77 and 78. A sensor that accurately characterizes the driver's skin temperature will produce a measurement that differs significantly from the ambient air temperature measurement. This is because the normal skin temperature of the person's face is higher than a typical target temperature for the passenger compartment air and will generally differ from the ambient air temperature, even before the HVAC system reaches thermal equilibrium.By comparing the first and second temperature measurements of the infrared sensors with the actual temperature in the passenger compartment, the temperature that deviates most from the actual passenger compartment temperature can be chosen as the actual body temperature.

[0024] As in Fig. As shown in Figure 8, infrared measurements are obtained in step 80. The ambient air temperature is measured in step 81. In step 82, the infrared measurements are compared with the ambient air measurements, and the temperature with the greatest deviation is chosen as the body temperature. In step 83, the HVAC system is controlled appropriately to adjust for the body temperature using a suitable type of feedback control.

Claims

[1] Device in a passenger compartment (20) occupied by a person (42), comprising: a skin temperature sensor to measure the actual skin temperature (43) of the person (42); a passenger compartment temperature sensor (26) for measuring an actual passenger compartment temperature (44) of the ambient air in the passenger compartment (20); an HVAC system to provide a heated and cooled airflow into the passenger compartment (20); a control module that includes means to store a target passenger compartment temperature and to control the HVAC system according to a first error between the target passenger compartment temperature and a passenger compartment temperature averaged according to a first time constant (44) and a personalization module (40) that includes means to provide a recommended target skin temperature, to choose between accepting the recommended target skin temperature and entering a desired target skin temperature, to save the selected target skin temperature to determine a compensation to be applied to the target passenger compartment temperature, the value of which depends on the first error and on a second error between the selected target skin temperature and a skin temperature averaged according to a second time constant, to determine a modified target passenger compartment temperature and to control the HVAC system according to the modified target passenger compartment temperature, wherein the second time constant is longer than the first time constant. [2] Device according to claim 1, wherein the compensation is zero when the first error is greater than a first threshold. [3] Device according to claim 1, wherein the personalization module (40) further comprises means for determining the compensation in response to the second error, multiplied by a gain factor. [4] Device according to claim 3, wherein the personalization module (40) further comprises means for determining the gain factor in response to corresponding magnitudes of the first error and the second error. [5] Device according to claim 3, further comprising a surface map (60) for correlating corresponding magnitudes of the first error and the second error with a value for the gain factor. [6] Device according to claim 1, further comprising means for determining the average passenger compartment temperature according to a formula CTk¯=αCTCTk−1¯+(1−αCT)CTk, where CTeine passenger compartment temperature, α CT the filter gain between 0 and 1, which defines the first time constant, and k is an index. [7] Device according to claim 1, further comprising means for determining the average skin temperature according to a formula BTk¯=αBTBTk−1¯+(1−αBT)BTk, where BT is a skin temperature, α BT the filter gain between 0 and 1, which defines the second time constant, and k is an index. [8] Device according to claim 1, further comprising means for determining the average passenger compartment temperature according to a formula CTk¯=αCTCTk−1¯+(1−αCT)CTk, where CT a passenger compartment temperature, α CT the first time constant and k is an index; to determine the average skin temperature according to a formula BTk¯=αBTBTk−1¯+(1−αBT)BTk, where BT is a skin temperature and α BT the second time constant are; to determine the first error according to a formula CTerr(k)=CTtar(k)−CTk¯, where CT err The first error and CT tarthe target passenger compartment temperature; to determine the second error according to a formula BTerr(k)=BTtar(k)−BTk¯, where BT err the second error and BT tar the target skin temperature; and to determine an updated target passenger compartment temperature according to a formula CTtar(k)=CTtar(k−1)+K1BTerr(k), where K1 is the amplification factor. [9] Device according to claim 1, wherein the skin temperature sensor comprises an infrared sensor which is mounted in a steering wheel (21) of the vehicle and is directed towards a face of the person (42). [10] Device according to claim 1, wherein the skin temperature sensor comprises first and second infrared sensors (32, 33) which are mounted in a steering wheel (21) of the vehicle and are directed towards a left side or a right side of a person's face (42), and wherein the personalization module (40) compares the temperature measurements of the infrared sensors (32, 33) with the measured actual passenger compartment temperature (44) to determine the actual skin temperature. [11] Device according to claim 1, further comprising a user interface (28) wherein the target passenger compartment temperature includes a manual setting by a user, which is selected via the user interface (28). [12] Device according to claim 1, further comprising a user interface (28) wherein the input of the desired target skin temperature includes a manual setting by the user, which is selected via the user interface (28). [13] Device according to claim 12, wherein the personalization module (40) further comprises means for displaying the recommended target skin temperature via the user interface (28). [14] Device according to claim 13, further comprising a wireless communication device (30) for receiving a preview of the outside air temperature (46) and means for providing the recommended target skin temperature in response to the preview of the outside air temperature (46). [15] Device according to claim 1, wherein the control module, the personalization module (40) and the means according to claims 6 to 8 and 14 are integrated into a programmable microcontroller.

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