Personalized air conditioning settings

Abstract

A vehicle's HVAC system includes a skin temperature sensor to measure the driver's actual skin temperature and a passenger compartment temperature sensor to measure the actual ambient air temperature in the passenger compartment. A controller module stores a target passenger compartment temperature, which it uses to control the HVAC system based on 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, which it uses to adjust the HVAC system 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.

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] The present invention 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. These adjustments, necessary to ensure stable system operation, are subject to certain limitations.

[0007] 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.

[0008] Fig. Figure 1 is a block diagram of an HVAC system with automatic temperature control.

[0009] Fig. Figure 2 is a schematic and block diagram of parts of an HVAC system and controller according to the invention.

[0010] Fig. Figure 3 is a block diagram that illustrates the present invention in more detail.

[0011] Fig. Figure 4 is a flowchart of a preferred method of the invention.

[0012] Fig. Figure 5 is a graphical representation of a diagram for determining an amplification factor.

[0013] Fig. Figure 6 shows a first embodiment of relative orientations of infrared temperature sensors on a steering wheel, directed towards a driver.

[0014] Fig. Figure 7 is a graphical representation of sample temperature data.

[0015] Fig. Figure 8 is a flowchart showing a preferred method for determining a person's skin temperature in a vehicle.

[0016] Referring to Fig. 1 is an electronic automatic temperature control system (EATC) 10 state of the art for climate control in a passenger compartment 11 a transport vehicle shown. An EATC controller. 12 receives ambient air temperature measurements from a sensor 13 , which is in the passenger compartment 11is arranged. Using feedback control, the EATC determines 12 the operation of a blower 14 , a heat source 15 and a cooling source 16 The temperature measurement, heating and cooling functions can be used to implement a multi-zone climate control system as known in the prior art, depending on the zones in the passenger compartment. 11 to be duplicated.

[0017] The present invention builds upon the EATC system. Fig. 10. 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 particular zone. In a transport vehicle, many journeys involve only a driver. During such times, modifying the operation of the EATC system to optimize driver comfort can be highly desirable, as it can also lead to energy savings.

[0018] A system according to the invention is in Fig. 2 shown in more detail. In a passenger compartment 20 There is a steering wheel 21 in front of a driver. A user interface 22 , which is typically mounted on a dashboard, can be an information display 23, an adjustment knob 24 and function keys 25 exhibit an ambient air temperature sensor. 26 measures the passenger compartment temperature in the conventional way. An external temperature sensor 27 It can be mounted outside the vehicle, outside the passenger compartment, to determine the temperature. To obtain a temperature forecast and / or as an alternative means of obtaining the outside temperature, a wireless communication system is used, as described below. 30 and an antenna 31 provided.

[0019] A pair of infrared temperature sensors is used to measure the driver's skin temperature. 32 and 33 on the steering wheel 21 attached. From various registers, including registers 35 , heated or cooled airflow is supplied to the driver.

[0020] A control device for carrying out the present invention is in Fig. 3 shown in more detail. A driver personalization function. 40 is implemented as a module that works with the controller module 22 which works in conjunction with automatic temperature control. The module 40 can be a software module that runs on the same electronic programmable microcontroller in the EATC system 22 or can be executed by a device in a separate box. A skin temperature target command is issued by the driver personalization function. 40 via a selector switch 41 (i.e., a driver-operated switch to select between a conventionally provided zone setpoint temperature and a personalization mode using the skin temperature target command) to the EATC system 22 delivered. As described below, the driver personalization function 40It provides a recommended target value for the driver's skin temperature. The personalization function is used by the driver. 42 regulated, which controls the user interface for turning the function on or off 40 adjusts. If a personalized setting is desired, the driver rates 42 The recommended target value is used, and then this temperature is adopted, or a different temperature is entered via the user interface.

[0021] The driver personalization function 40 receives various temperature measurements, including skin temperature 43 , interior (i.e. passenger compartment) ambient temperature 44 , outside ambient air temperature 45 and temperature forecast 46 The temperature forecast 46It can be adjusted to reflect upcoming outside temperature conditions based on 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 established models that relate various temperature conditions to a person's skin temperature and their personal comfort level, the personalization function then adjusts the settings accordingly. 40 a recommended target skin temperature based on known physical / perceptual models.

[0022] 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 step 4 are modified. In personalization mode for optimizing climate control according to a vehicle occupant's skin temperature, improved feedback control is based on body temperature (i.e., skin) 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. Measurements of the passenger compartment temperature are therefore taken in step 1. 50 filtered according to a first time constant. The skin temperature measurements are taken in step 51 filtered according to a second time constant that is longer than the first time constant. 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, in step 53A tunable gain factor is determined for calculating a compensation to be applied to the target temperature in the passenger compartment. The passenger compartment target temperature is determined in step 54 The system is updated and then resumes conventional operation using the modified target value for feedback control of the passenger compartment temperature.

[0023] 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: 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 BT The filter amplifiers, which define the second time constant, and k are an index. The first error is determined according to a formula: where CT err The first error and CTtar The target passenger compartment temperature (i.e., the one used by the EATC system as a feedback target value) is calculated. The second error is determined according to a formula: 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: CT tar (k) = CT tar (k – 1) + K1BT err (k) where K1 is the tunable gain factor for a normalized gain factor between 0 and 1. The size of BT err is applied when the tunable normalized K1 range is between -1 and 1, in order to provide appropriate directional compensation for the passenger compartment temperature.

[0024] A control basis is provided for the value of the gain factor K1, which is intended to limit the amount of change in each iteration and prevent changes during times when the passenger compartment temperature error is greater than a threshold difference (e.g., 5°F). One embodiment of the control 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 amplification factor K1 is represented as a three-dimensional surface map. 60 shown, which displays the value for K1 for different values ​​of the passenger compartment temperature error along the axis 61 , of the body temperature error along the axis 62 and the K1 value along the axis 63 defined. 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: CT tar (k) = CTtar (k – 1) + K1|BT err (k)|

[0025] The values ​​for the passenger compartment temperature error and the body temperature error are shown on 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, the value of K1 approaches zero at high values ​​of the passenger compartment temperature error along certain regions. 64 and 65 the surface 60 Zero. If the body temperature error is close to zero, the surface 60 analogous to a zero value as in region 66shown. When the passenger compartment temperature error is close to zero, but the body temperature error lies between the upper and lower thresholds, increasingly higher values ​​of the gain factor K1 are shown, as in regions 67 and 68 shown.

[0026] 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. The result is shown in Figure 5. Using the resulting value K1 from such equations, a regression delta_CT is then calculated. tar calculated as follows: delta_CT tar (k) = K1BT err (k) for normalized gain factors between 0 and 1, and delta_CT tar (k) = K1|BT err (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: 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.

[0027] For robust skin temperature measurements, as in Fig. Six areas are shown where the infrared temperature sensors mounted on the steering wheel provide detection. The face of a person 70 Depending on body size or posture, the person in a particular seat (for example, the driver's seat) is in a certain position with respect to the temperature sensors. 72 and 74 on the steering wheel 71 For positions other than the driver's seat, the sensors can be used. 72 and 74 They 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 indicates a detection region 73 on and the infrared sensor 74 indicates a detection region 75 which are directed at slightly different heights and sideways to the right or left side of the person's face 70are spaced apart. The use of detection regions with slightly different heights and slightly different lateral regions increases the probability that at least one temperature measurement will correspond to the face of a driver of unknown height.

[0028] The temperature measurements are evaluated to ensure that the sensor receiving the better skin temperature reading is used as described in the instructions. Fig. 7 is used as shown. The line 77 represents an ambient air temperature measurement, as obtained in the passenger compartment. The line 78 represents temperature measurements from an infrared sensor and the line 79This 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 measure precise skin temperature, will accurately track the ambient air temperature, as indicated by the close alignment of the lines. 77 and 78As shown, a sensor that accurately characterizes the driver's skin temperature produces 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 usually differs from the ambient air temperature, even before the HVAC system reaches thermal equilibrium. By comparing the first and second temperature measurements from the infrared sensors with the actual temperature in the passenger compartment, the temperature that deviates most from the actual passenger compartment temperature can be selected as the actual body temperature.

[0029] As in Fig. 8 will be shown in step 80 Infrared measurements were obtained. The ambient air temperature is measured in step 81 measured in step 82The 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 in a suitable manner to adjust body temperature using an appropriate type of feedback control.

Claims

[1] Device in a passenger compartment of a transport vehicle occupied by one person, comprising: a skin temperature sensor to measure the actual skin temperature of the person; a passenger compartment temperature sensor for measuring the actual temperature of the ambient air in the passenger compartment; an HVAC system to provide a heated and cooled airflow into 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. [2] Device according to claim 1, wherein the compensation is zero when the first error between the target passenger compartment temperature and the filtered actual passenger compartment temperature is greater than a first threshold. [3] Device according to claim 1, wherein the compensation is determined as a reaction to the second fault, multiplied by a gain factor. [4] Device according to claim 3, wherein the gain factor is determined in response to corresponding magnitudes of the first error and the second error. [5] Device according to claim 3, further comprising a map 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, wherein the determination of the filtered actual passenger compartment temperature is carried out according to a formula where CT is the actual 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, wherein the determination of the filtered actual skin temperature is carried out according to a formula where BT is the actual 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, wherein the determination of the filtered actual passenger compartment temperature is carried out according to a formula where CT is the actual passenger compartment temperature, αCT the first time constant and k is an index; in which the determination of the filtered actual skin temperature is carried out according to a formula where BT is the actual skin temperature and α BT the second time constant is; wherein the determination of the first error is carried out according to a formula where CT err The first error and CT tar the target passenger compartment temperature is; wherein the determination of the second error is carried out according to a formula where BT err the second error and BT tar the target skin temperature is; and in which the determination of an updated target passenger compartment temperature is carried out according to a formula CT tar (k) = CT tar (k – 1) + K1BT err (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 of the vehicle and is directed towards a face of the person. [10] Device according to claim 1, wherein the skin temperature sensor comprises first and second infrared sensors which are mounted in a steering wheel of the vehicle and are directed towards a left side or a right side of a person's face, and wherein the personalization module compares the temperature measurements of the infrared sensors with the measured actual passenger compartment temperature to determine the actual skin temperature. [11] Device according to claim 1, further comprising a user interface wherein the target passenger compartment temperature includes a manual setting by the user, which is selected via the user interface. [12] Device according to claim 1, further comprising a user interface wherein the target skin temperature includes a manual setting by the user, which is selected via the user interface. [13] Device according to claim 12, wherein the personalization module calculates a recommended skin temperature and displays the recommended skin temperature via the user interface. [14] Device according to claim 13, further comprising a wireless communication device for obtaining a preview of the outside air temperature, wherein the recommended skin temperature is calculated in response to the preview of the outside air temperature. [15] Device according to claim 1, wherein the control module and the personalization module are integrated into a programmable microcontroller.