METHOD FOR ESTIMATING THE TEMPERATURE OF A VEHICLE CABIN

Abstract

Method for estimating the temperature of a vehicle cabin (14) and for using the estimated cabin temperature, the method comprising: Obtaining a surface temperature from a first interior surface of the vehicle cabin (14) via at least one temperature sensor (40); Estimating the surface temperature of a second interior surface using a value for heat transfer by solar radiation and a value for heat transfer by convection for the second interior surface as well as the surface temperature of the first interior surface of the vehicle cabin (14); Estimating the heat transfer from the first and second interior surfaces to the cabin air inside the vehicle cabin (14) using the surface temperature of the first and second interior surfaces via a processor; Estimating the cabin temperature of the vehicle (12) using at least the estimated heat transfer via a processor; Control at least one feature of a climate control system (32) of the vehicle (12) using the estimated cabin temperature; wherein the heat transfer is estimated using the respective heat transfer coefficients for the first and second internal surfaces and the respective surface temperature, wherein the respective heat transfer coefficient is determined as a function of the air flow rate of the air conditioning unit of the climate control (32).

Description

TECHNICAL AREA

[0001] The present invention relates generally to a method for estimating the temperature of a vehicle cabin. BACKGROUND

[0002] A typical vehicle with air conditioning includes a temperature sensor that measures the interior air temperature in the passenger compartment (see, for example, DE 101 21 192 A1). The air conditioning system uses these sensor measurements as input to control the temperature in the vehicle cabin. The climate control system determines, at a minimum, the appropriate outlet temperature to achieve a desired cabin temperature. However, the temperature reading from the vehicle's temperature sensor can deviate significantly from the actual cabin temperature due to factors such as air stratification, heat retention in the dashboard, and heat dissipation from nearby vents. The temperature measured by the vehicle's temperature sensor can differ by up to ten degrees Celsius from the air temperature at breathing level (i.e., the air temperature adjacent to the driver's face).An automatic climate control system that reacts to the temperature sensor can therefore overheat or overcool the cabin. Furthermore, this overheating or overcooling can worsen over time because the control algorithm used cannot accurately track the actual cabin temperature.

[0003] Accordingly, it is desirable to provide an accurate method or device for estimating the cabin temperature. Furthermore, it is desirable to provide a method or device that offers real-time corrections to the cabin temperature estimate. Additionally, it is desirable to provide a method or device for estimating the cabin temperature that eliminates the need for a cabin air temperature sensor. Further desirable functions and features will become apparent from the detailed description below and the attached claims in conjunction with the accompanying drawings, as well as the preceding technical field and background information. SUMMARY

[0004] According to the invention, a method for estimating the temperature of a vehicle cabin and for using the estimated cabin temperature is presented, which is characterized by the features of claim 1. DESCRIPTION OF THE DRAWINGS

[0005] The exemplary embodiments are described below in conjunction with the following drawing of the FIGS, where identical numbers denote identical elements, and where the following applies: Fig. Figure 1 is a side view of a vehicle section according to one embodiment; Fig. Figure 2 is a diagram of a control module system according to the various embodiments; and Fig. Figure 3 is a flowchart that outlines the steps of an algorithm according to one embodiment. DETAILED DESCRIPTION

[0006] With reference to now Fig. Figure 1 shows a vehicle 12 incorporating an automatic climate control system 32 according to various embodiments. Although the figures shown herein represent an example with specific arrangements of elements, actual embodiments may include additional intermediate elements, devices, features, or components. It should be noted that Fig. 1 is for illustrative purposes only and may not be to scale.

[0007] As shown, the vehicle 12 includes at least one HVAC controller 34. The HVAC controller 34 is further described herein because it is intended for automatic climate control, e.g., an HVAC controller 34. However, the HVAC controller 34 can have more extensive functionality with respect to controlling the vehicle 12. For example, the HVAC controller 34 controls one or more components of the vehicle 12. The components can be connected to autonomous or semi-autonomous systems of the vehicle 12. For example, the HVAC controller 34 can control vehicle components of a braking system (not shown), a steering system (not shown), and / or a suspension system (not shown) of the vehicle 12, each of which can be controlled autonomously (e.g., without driver input) and / or semi-autonomously (e.g., with some driver input).

[0008] In various embodiments, the HVAC controller 34 includes at least one processor 33 and one memory 35. The memory 35 stores instructions that can be executed by the processor 33, including the methods described herein for automatic climate control and temperature estimation with respect to the Fig. 1 to 3. The instructions in memory 35 can contain one or more separate programs, each containing an ordered list of executable instructions for implementing logical functions.

[0009] When the HVAC control unit 34 is in operation, the task of the processor 33 is to execute instructions from memory 35, to route data to and from memory 35, and generally to control functions of the vehicle 12 according to the instructions. The processor 33 can be a custom-made or a commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors connected to the HVAC module 30, a semiconductor-based microprocessor (in the form of a microchip or chipset), a macroprocessor, or generally a device for executing instructions.

[0010] In various embodiments, the processor 33 executes the instructions of the automatic climate control 32. Generally, the automatic climate control 32 is configured to estimate the cabin temperature of the vehicle 12 and to use the estimated cabin temperature to control at least one feature of the climate control 32. The cabin temperature estimate can be based on solving a heat balance equation with terms for the heat flow by convection to a vehicle cabin 14 of the vehicle 12 and optionally at least one of the heat flows from a heating, ventilation, and air conditioning (HVAC) module 30 and heat generated by one or more occupants of the vehicle 12, as described in more detail below. The automatic climate control 32 can use the cabin temperature estimate as input for controlling one or more settings of the climate control system (e.g., airflow, temperature, etc.).

[0011] With reference to Fig. Figure 1 shows a section of a vehicle 12. The vehicle 12 includes a passenger compartment or cabin 14, which is enclosed by a roof 16, a windshield 18, a floor 20, and doors 22 with windows 24. The windows 24 can, for example, include the front left, front right, rear left, and rear right windows. An instrument panel 26 is located in front of the driver's seat 28. Behind the instrument panel 26 is an HVAC module 30 (or air conditioning unit), which is part of a climate control system 32. A fan 36 is connected to the HVAC module 30 to create an airflow through it. The HVAC module 30 includes an HVAC controller 34, which contains the processor 33 and the memory 35.

[0012] The automatic climate control 32 includes one or more temperature sensors for detecting the temperature on the surface of the vehicle 12. The one or more temperature sensors can be implemented as a thermistor, an infrared sensor, or another type of temperature sensor. The one or more temperature sensors can be mounted on the dashboard 26, the windshield 18, or elsewhere to enable surface temperature measurements. In one embodiment, a solar load sensor is included, which can be mounted on a surface 44 of the dashboard 26 to measure the temperature at that location, as well as the intensity and, optionally, the angle of the solar load. In various embodiments, the climate control 32 includes an ambient air temperature sensor 42, which measures the ambient air temperature outside the vehicle 12.In various embodiments, the climate control unit 32 includes a windshield temperature sensor 37. The windshield temperature sensor 37 can be integrated into a relative humidity sensor (RHS) located on the cabin side of the windshield 18 behind the rearview mirror 39. The one or more temperature sensors operate in conjunction with the HVAC control unit 34.

[0013] Fig. Figure 2 represents an embodiment of a control module system, which in various embodiments is implemented by the processor 33 and the memory 35 of the HVAC controller 34 to achieve the estimation of the cabin temperature and its subsequent use. The HVAC controller 34 is configured to estimate the cabin temperature of the vehicle 12. To achieve this, a cabin air temperature module 62 is provided, which can output an estimate of the breathing air temperature. The cabin air temperature module 62 is configured to output an estimated value for the cabin temperature, which can be the cabin air temperature at the breathing level of a vehicle occupant, at foot level, or at another location.

[0014] The cabin air temperature module 62 is configured to solve a heat balance equation that includes terms representing heat transfer from the HVAC module 30 and heat transfer by convection from the interior surfaces of the vehicle cabin 14. The main interior surfaces of the vehicle cabin 14 may include one or more of the following: the roof 16, the windshield 18, the floor 20, the doors 22, the windows 24, the dashboard 26, etc., as further described below.

[0015] The heat balance equation can also include a term representing the heat generated by one or more vehicle occupants. The number of vehicle occupants can be assumed or determined based on an input from, for example, a seatbelt sensor (or other means) that indicates when a seatbelt has been fastened.

[0016] The heat balance equation can be expressed in the following form: Q_in−Q_out+Q_generated=δQ where (Q_in - Q_out) represents the net heat transfer to the cabin interior, Q_generates the heat supplied by the occupants and δQ the change in the thermal energy of the cabin interior.

[0017] The net heat transfer to the cabin interior can be determined based on the heat transfer by convection between the interior surfaces and the air in the vehicle cabin 14 and the heat transfer through the HVAC module 30.

[0018] In the exemplary embodiment of Fig. 2. Heat transfer by convection is determined via an internal convection module 70, as explained in more detail below. The internal convection module 70 uses, for example, as input parameters at least the surface temperatures of the interior surfaces, which are determined by the surface temperature module 64, and the heat transfer coefficients, which can be stored in the memory 35. The heat transfer coefficients can be selected based on at least one or more settings of the HVAC module 30, such as airflow rate, air distribution mode, and vehicle speed.

[0019] In the Fig. In the example shown in Figure 2, the heat transfer of the HVAC module 30 is determined by an exhaust air energy module 76, which is described in more detail below. The exhaust air energy module 76 can determine the heat transfer into the vehicle cabin 14 through the HVAC module 30 using at least one air volume flow and air temperature output through the blower 36.

[0020] In the example of Fig. 2. The surface temperature module 64 is configured to determine the surface temperatures of the interior surfaces of the vehicle cabin 14 using at least one or more solar load values ​​from a solar load module 60, the outside air temperature from the ambient air temperature sensor 42, and one or more corrected temperature values ​​from a sensor offset correction module 66. The sensor offset correction module 66 is configured to correct for contamination in the outputs of one or more of the temperature sensors 37 and 40 described above.

[0021] In various embodiments, the HVAC control unit 34 receives, in particular, the surface temperature module 64 thereof, a surface temperature of at least one first interior surface of the vehicle cabin 14, based on the measured values ​​from one or more of the temperature sensors 37, 40, 42 described above. In various embodiments, the at least one first interior surface of the vehicle cabin 14 includes the surface 44 of the dashboard 26. In various embodiments, the at least one first interior surface of the vehicle cabin 14 includes the inside of the windshield 18.

[0022] The surface temperature module 64 is configured to correlate the detected temperature of at least one first interior surface of the vehicle cabin 14 with one or more other (or second) interior surfaces. The remaining interior surface temperatures can be determined by linear correlations with the real-time data of one or more of the sensors 37, 40, 42, or other temperature measuring devices described above. For example, the surface of the body elements of the vehicle cabin 14, the windows 24, the windshield 18, or the rear window (not shown) use a linear correlation with the temperature measured by the solar sensor. In this example, vehicle windows (e.g., the windshield 18, the rear window, and the windows 24) use a linear correlation with the windshield temperature measured by the windshield temperature sensor 37.The linear correlation process uses the measured temperature and other parameters, such as information about the solar load, as described in more detail below. For vehicles without a windshield temperature sensor 37, the temperature of the vehicle windows uses a linear correlation with the ambient air temperature sensor 42.

[0023] To obtain the minimum first interior surface temperature of the vehicle cabin 14 in various embodiments, the HVAC controller 34 receives the temperature measurement from, for example, the solar load sensor for use in estimating the interior surface temperature of the dashboard 26. Although positioned correctly, this measurement may, under certain circumstances, deviate to some extent from the actual surface temperature 44. For example, the solar load sensor may be located near a defroster outlet and thus be relatively cooler during active defrosting or in the event of a leak from the defroster outlet. As another example, the solar load sensor may be required to correct for the absorption of solar radiation by the surface 44 of the dashboard 26. Therefore, a correction or offset may be applied to the measurements of the solar load sensor.The correction or offset can be performed by the sensor offset correction module 66. Correction values ​​can be obtained experimentally and are stored in the memory 35 of the HVAC controller 34. The correction values ​​can be viewed and determined based on at least one defrost volume flow from the HVAC module 30 and the solar intensity.

[0024] To determine at least one initial interior surface temperature of the vehicle cabin 14 in various additional or alternative embodiments, the HVAC controller 34 receives the temperature measurement from the windshield temperature sensor 37 for use in estimating the interior surface temperature of the windshield 18. Due to the absorption of solar radiation by the windshield temperature sensor 37, a correction may be necessary for a more accurate estimation of the interior surface temperature of the windshield 18. The correction or offset can be performed by the sensor offset correction module 66. Correction values ​​can be obtained experimentally and are stored in the memory 35 of the HVAC controller 34. The correction values ​​can be viewed and determined based on at least one solar intensity.

[0025] The surface temperature module 64 is configured to estimate one or more other (secondary) interior surface temperatures. In one embodiment, sixteen surfaces are estimated, including ten opaque surfaces (four doors, roof, engine firewall, dashboard, rear seats / border, parcel shelf, and floor) and six transparent surfaces (four side windows, windshield, and rear window). For each surface, the geometry, orientation, optical properties, and material properties are known and stored in the memory 35 of the HVAC controller 34. Using this data, the angle of solar radiation relative to the respective surface can be determined, together with the solar load sensor data on the angle and intensity of solar radiation.

[0026] In various embodiments, the surface temperature module 64 is configured to correlate the at least one first interior surface temperature of the vehicle cabin 14 with one or more other interior surface temperatures using a specific heat transfer via the other interior surface by convection and a specific heat transfer via the other interior surface by solar absorption. In various embodiments, the surface temperature module 64 is configured to correlate the interior surface temperature of the windshield 18, as described above, with other transparent (e.g., glass) surfaces of the vehicle 12, such as the windows 24 and the rear window (not shown).In various embodiments, the surface temperature module 64 is configured to correlate the interior surface temperature of the surface 44 of the instrument panel 26 with other opaque interior surfaces or interior surfaces of body elements, such as the left front side door, the left rear side door, the right front side door, the right rear side door, the roof, the engine firewall (vertical part of the instrument panel), the rear seats, the parcel shelf (storage area), and the floor. Correlation can also be performed for the windshield 18 and the surface 44 of the instrument panel 26, or the corrected temperature values ​​from the sensor offset correction module 66 can be used.

[0027] The correlation described above can be carried out with the surface temperature modulus 64 according to the following equation for the transparent or glass interior surfaces: Tg=Tb+Toffset where Tg is the glass temperature estimate, Tb is a base temperature, and Toffset is the offset temperature obtained from the amount of heat exchanged by each glass pane with the environments (outside and inside the vehicle cabin 14). This correlation is performed for each glass pane to obtain an estimate of the internal surface area of ​​each glass pane.

[0028] Tb, the base temperature, can be the temperature of the inner surface of the windshield 18, obtained from the sensor offset correction module 66, or it can be based on a measured temperature reading for the windshield, as described above. Alternatively, the base temperature Tb is taken from the ambient air temperature sensor 42.

[0029] Toffset can be determined based on a convective heat transfer value for the inner glass surface from the internal convection module 70 and a solar heat transfer value from the solar load module 60, as described below. Toffset can be determined based on external and internal values ​​for heat transfer by convection, i.e., heat transfer by convection to the outside of the vehicle 12 and heat transfer by convection to the inside of the vehicle 12. Toffset is determined independently for each glass pane based on the heat transfer values ​​determined for that specific pane. In particular, the net heat transfer (Qnet), which considers the internal heat transfer by convection (Qconv, intr) and the heat transfer by external convection (Qconv, intr) for the glass, as well as the heat transfer by solar radiation (Qsolar), can be used as input for a lookup table to determine the Toffset.The net heat transfer value can be determined from the formula: Qnet=Qconv,extr−Qconv,intr+Qsolar.

[0030] The correlation described above can be carried out with the surface temperature module 64 according to the following equation for the opaque inner surfaces of the body elements: Ts,intr=Tb+Toffset, where Ts,intr is the estimated internal surface temperature of the body panel, Tb is the base temperature corresponding to the surface temperature 44 of the instrument panel 26 obtained by the sensor offset correction module 66, or otherwise obtained based on a captured temperature measurement for the body panel. Toffset is the offset temperature resulting from the heat exchange between each internal surface and the environment. This heat exchange includes heat transfer by convection and absorption of solar radiation. Convective heat transfer with the cabin air is taken into account. The internal surface temperature is estimated by the surface temperature module 64 for each surface, with Toffset being determined independently for each surface of the body panel.

[0031] Toffset can be determined based on a convective heat transfer value for the inner glass surface from the internal convection module 70 and a solar heat transfer value from the solar load module 60, as described below. Specifically, the net heat transfer (Qnet), which considers the internal heat transfer by convection (Qconv, intr) for the body panel and the heat transfer by solar radiation (Qsolar), can be used as input for a lookup table to determine the Toffset. The net heat transfer value can be calculated from the formula: Qnet = Qsolar - Qconv, intr.

[0032] The solar load module 60 is configured to determine the solar load on each of the interior surfaces area by area. The solar load module 60 receives inputs of physical cabin data from the physical cabin data module 68 and information on ambient solar irradiance to determine the heat transfer from solar irradiance for each interior surface. The physical cabin data can include the window orientation, surface areas, and optical properties of the windows, including transmissivity and absorptivity to account for solar irradiance. The ambient solar irradiance information can include direction and intensity. Ambient solar irradiance can be determined via the solar load sensor and, optionally, via time and location data. The physical cabin data can be stored on memory 35 and retrieved via the physical cabin data module 68.

[0033] A portion of the solar radiation is transmitted through the vehicle's glazing (windows 24, windshield 18, and rear window) and absorbed by the interior surfaces of body panels such as doors, dashboard, parcel shelf, etc. Vehicle glazing comprises those parts of the vehicle through which the occupants can see the outside environment, as distinguishable body panels such as door frames, floor covering, roof, etc. Vehicle glazing generally, but not exclusively, consists of glass. The transmission of solar radiation depends on at least two factors: the direct solar transmittance of the glass panes and the orientation of the glass panes to the sun (azimuth and elevation angles of the surface normals). A portion of the solar radiation is reflected and thus has no effect on the cabin temperature. A portion of the incident solar radiation is absorbed partly by the glass panes and partly by the body panels.The absorption of solar radiation by the glass panes depends on the absorption capacity of the glass panes.

[0034] The solar load module 60 is configured to calculate the absorbed heat from solar radiation through the vehicle glazing using the solar absorption of the panes from the physical cabin data module, the solar intensity, and the solar angle relative to the normality of the glass. The solar intensity can be determined via the solar load sensor. The solar angle can also be determined from the solar load sensor or from time and location information from a GPS module of the vehicle 12.

[0035] The solar load module 60 is configured to calculate the absorbed heat from solar radiation through the interior surfaces of the body panels, which is transferred through the vehicle glazing. The body panels can include: the left front door, the left rear door, the right front door, the right rear door, the roof, the engine firewall (vertical part of the dashboard), surface 44 or dashboard 26 (horizontal part of the dashboard), the rear seats, the parcel shelf, and the floor.

[0036] The solar load module 60 can be configured to use one or more matrices that logically distribute the transmitted solar radiation across the interior surfaces of the cabin, ensuring that none of the transmitted solar energy is lost from inside the cabin. The solar load module can further calculate the absorbed heat from the solar radiation by the interior surfaces of the body panels, utilizing the absorption capacity of each surface and the angle of the sun. Any solar radiation reflected from the interior surfaces of the body panels can be considered as being absorbed equally by all interior surfaces of the body panels. The distribution of solar radiation and the solar absorption capacity of the vehicle 12 can be obtained from the physical cabin data module 68.

[0037] The solar load module 60 is configured to dissipate the absorbed heat from solar radiation via the inner surfaces of the body elements and the absorbed heat from solar radiation via the vehicle windows.

[0038] The output corresponds to Qsolar for each of the aforementioned surfaces. The surface temperature module 64 is configured to receive these absorbed heat values ​​in order to determine the temperature of each individual glass interior surface and body panel components, as described above (e.g., for use in offset determination, as described above).

[0039] The interior convection module 70 is configured to determine convective heat transfer per unit area from the interior surfaces of the vehicle cabin 14 to the interior air of the vehicle cabin 14. This is calculated by multiplying the heat transfer coefficient for the interior surface of the shell elements, including the glass and body elements of the vehicle 12, by the temperature difference obtained by subtracting the estimated breathing temperature for the cabin (Tbreath,fl) from the interior surface temperature of the shell elements (Ts,intr). The interior convection module 70 can be used according to the following equation: Qconv,intr=hi.J_fl.(Ts,intr−Tbreath,fl), where hi is the heat transfer coefficient for the inner surface and Qconv,intr is the heat transfer per unit area required by the surface temperature module 64 to determine Toffset, as described above. The parameter J_fl is an optional constant representing the heat flux distribution obtained through experimentation.

[0040] The temperature of the inner surfaces, Ts,intr, is determined by feedback from the surface temperature module 64 and is taken as the last calculated value for Ts,intr. The breathing level temperature, Tbreath,fl, is determined by feedback from the cabin air temperature module 62 and is taken as the last calculated value for Tbreath,fl. Although the breathing air temperature was used in this exemplary embodiment, it is intended that other cabin air temperatures from the cabin air temperature module 62 can also be used.

[0041] The heat transfer coefficients for each interior surface are determined from the HTC module 72. These coefficients can be stored in a table in memory 35. The table can be two- or three-dimensional. The two-dimensional table can contain heat transfer coefficients for each interior surface of the shell elements, including vehicle glazing and body panels, with different inputs for each shell element depending on the air distribution mode of the HVAC module 30. The three-dimensional table can also contain different heat transfer coefficients depending on the airflow setting of the HVAC module 30. In some embodiments, the heat transfer coefficients are obtained from CFD (Computational Fluid Dynamics) simulations.

[0042] The HTC module 72 is configured to return the heat transfer coefficients hi to the internal convection module 70 based on at least one setting of the HVAC module 30 for use in determining Qconv,intr.

[0043] The interior convection module is further configured to determine the convective heat transfer per unit area (Qconv,extr) from the outside air to the vehicle glazing by multiplying the external heat transfer coefficient (he) by a temperature difference obtained by subtracting the interior surface temperature of the glazing (Tg) from an input signal of the outside air temperature (OAT). This calculation yields the convective heat transfer to the cabin exterior for each of the vehicle windows. Qconv,extr=he.(OAT−Tg)

[0044] The disc temperature Tg can be obtained as the last calculated value by feedback from the surface temperature module 64. The outside air temperature OAT is obtained based on an output from the ambient air temperature sensor 42.

[0045] The external heat transfer coefficients are obtained from the HTC module 72. The HTC module can access the corresponding values ​​for the heat transfer coefficient in memory 35. The HTC module can return the external heat transfer coefficients based on the vehicle speed. The external heat transfer coefficients are stored for each glass pane of the vehicle 12, in addition to the different values ​​that vary depending on the vehicle speed.

[0046] It should be noted that, unlike conventional methods, the method according to the present embodiment relies on the fact that the vehicle manufacturer knows all the physical dimensions and material properties of the vehicle cabin 14. Unlike conventional methods, this is also used in the numerical analysis to accurately predict the heat flow.

[0047] The interior convection module 70 is configured to determine the heat transfer of the vehicle windows by convection Qconv,extr, the heat transfer of each of the interior surfaces of the shell elements by convection Qconv,intr, and to return these heat transfer values ​​to the surface temperature module 64. The solar load module 60 is configured to determine the solar irradiance Qsolar for each of the interior surfaces of the shell elements and to return this heat transfer value to the surface temperature module. From Qconv,extr, Qconv,intr, and Qsolar, the surface temperature module 64 is able to determine the net heat transfer Qnet for each of the surface elements and a temperature offset Toffset. The temperature offset is used by the surface temperature module 64 to determine the temperature Tg and Ts,intr for each of the interior surfaces of the vehicle 12.

[0048] The surface temperature module 64 is configured to output the measured temperatures Tg and Ts,intr to the internal convection module 70 as feedback for subsequent iterations, as described above. The surface temperature module 64 is also configured to output the measured temperatures Tg and Ts,intr to the cabin air temperature module 62 for determining the cabin air temperature.

[0049] The cabin air temperature module 62 is configured to use the surface temperature estimates from the surface temperature module 64 and to estimate one or more cabin air temperatures based thereon. In the following exemplary embodiment, the cabin air temperature is the breathing air temperature. However, other cabin temperatures can be estimated, including the air temperature at foot level.

[0050] The cabin air temperature module 62 is configured to determine the heat flux from the HVAC module 30. The heat flux (Qhvac,fl) of the HVAC module 30 can be determined based on one or more exhaust energy parameters of the HVAC module 30. For example, the exhaust energy parameters can be airflow and air temperature. These parameters can be determined via the exhaust energy module 76 using one or more sensors of the HVAC module 30 or via the settings of the HVAC module. In an exemplary embodiment, the cabin air temperature module uses the following equation to determine the heat flux from the HVAC module 30: Qhvac,fl=m.cp.δT where m is the mass of air injected by the climate control system, cp is the specific heat capacity of the air, and δT is the temperature difference between the air injected by the climate control system 32 and the cabin air, e.g., at the occupant's breathing level. The cabin air temperature used to determine the temperature difference δT is obtained from a previous iteration of the present algorithm for determining the cabin air temperature. The specific heat capacity of the air cp is a constant parameter that can be accessed from memory 35.

[0051] The cabin air temperature module 62 is further configured to determine the heat transfer by convection Q_conv,fl between the interior surfaces and the air using the convective heat transfer per unit area Qconv,intr values ​​calculated by the interior convection module 70, and the interior surface areas for each surface determined from the cabin physical data module 68. The surface area can be stored in memory 35 and retrieved via the cabin physical data module 68.

[0052] The cabin air temperature module 62 is configured to estimate the cabin air temperature by solving the heat balance equation, as described above, with the input parameter of heat transfer by convection from each surface and the heat flux Qhvac,fl from the HVAC module. Specifically, the following equation can be used to determine the net rate of heat transfer, or heat flux Q_net,fl, to the cabin air: Qnet,fl=Qhvac,fl+Q_conv,fl

[0053] The cabin air temperature module 62 is configured to determine a change in the thermal energy δQfl inside the cabin based on the net heat transfer by convection from the interior surfaces of the vehicle cabin 14, the heat transfer from the HVAC module, and the heat generated by the vehicle occupants Qgenerated,fl. The following equation can be used: δQfl=Qnet,fl+Qgenerated,fl

[0054] Based on the change in thermal energy δQfl, the cabin air temperature module 62 is configured to calculate a change in cabin air temperature. For example, the following equation can be used: δT=δQ / (m.cp)=δQ / (ρ.V.cp) where m is the air mass inside the cabin in kg and ρ is the density of the air in kg / m³ 3 and V the volume of cabin air in m³ 3 is.

[0055] The cabin air temperature module 62 is configured to repeat these calculations to determine the change in cabin air temperature, thus enabling the determination of an absolute value for the cabin air temperature. The algorithms may require suitable initial values ​​for various parameters to determine the cabin temperature iteratively. The surface temperature module 64 is also configured for repeated operation to determine interior surface temperatures and may also require a suitable population of initial values. Similarly, the interior convection module 70 can be configured to iteratively determine the heat transfer values ​​for the interior surfaces and may require a suitable population of initial values.

[0056] In the preceding description of the cabin air, surface temperature, and interior convection modules 62, 64, 70, the cabin is treated as a whole. However, the calculations can be reformulated based on the same principles so that the vehicle cabin 14 is divided into several virtual zones. The heat flux from convection from the interior surface within this zone, the heat flux of an occupant in this zone, and the heat flux from the HVAC module 30 to this zone can be determined in such a way that the cabin air temperature in each zone can be determined. If necessary, a suitable crosstalk factor can be included, which can be determined experimentally and stored in memory 35. In this way, the cabin air temperature can be determined more locally.For example, the cabin air temperature for at least one of the following zones is determined: front right breathing level, front left breathing level, rear right breathing level, rear right breathing level, rear left breathing level, front right foot level, front left foot level, front left foot level, rear right foot level, and rear left foot level. The Cabin Air Temperature Module 62 can be configured to estimate multiple cabin air temperatures, one for each virtual zone. Furthermore, an average cabin air temperature can be determined based on the multiple zones.

[0057] The cabin air temperature module 62 is configured to output the estimated cabin air temperature, which can be used as a control input for the automatic climate control 32 to adjust the settings of the HVAC module 30 to achieve a desired cabin air temperature. The output can be used for display on the instrument panel 26.

[0058] With further reference to Fig. 3, and with further reference to the Fig. 1 and Fig. 2 A method for estimating the cabin air temperature of a vehicle and for using the estimated temperature is presented. The method estimates the cabin air temperature based on a model that estimates the temperatures of the interior surfaces for each interior surface of a cabin included in the model, based on heat transfer by convection and solar absorption. The model further estimates the heat transfer by convection based on previous values ​​for the estimated surface temperature for each interior surface and the estimated cabin air temperature and heat transfer coefficient for each interior surface. The method can be performed using a computer program executed by at least one processor, such as the processor 33 of the HVAC controller 34 of the HVAC module 30.

[0059] At step 100 of the procedure of Fig. 3 A surface temperature of at least one first interior surface of the vehicle cabin 14 is obtained based on sensor temperature measurements from one or more temperature sensors 37, 40, 42. In one embodiment, the HVAC controller 34 receives a surface temperature of an interior surface 44 of a body element, such as the dashboard 26, and optionally an interior surface of a window element, such as the windshield 18. Any suitable temperature sensor can be used for one or more temperature sensors.

[0060] In step 102, the solar absorption for the interior surfaces of the vehicle 12 included in the model is estimated. As described above, the solar absorption is estimated at least based on the solar intensity. Optionally, the solar absorption can also be estimated based on the angle of solar radiation in combination with the optical properties of the surface.

[0061] In step 104, the heat energy transfer by convection is estimated for each interior surface included in the model. This estimate can be based on heat transfer coefficients for each interior surface and also on previous estimates for the surface temperature of each interior surface and the cabin air temperature. The feedback of temperature estimates for each interior surface of vehicle cabin 14 according to step 106 and an estimate of the cabin air temperature according to step 110 is provided by lines 112 and 114 in Fig.Figure 3 shows the heat transfer coefficients for each interior surface. The heat transfer coefficients for each interior surface can be determined from memory 35 depending on at least one setting of the air conditioning system or HVAC module 30, taking into account a change in the heat transfer coefficient depending on an air distribution mode of the HVAC module 30 and the like.

[0062] In step 106, the surface temperatures of (second) interior surfaces included in the model are estimated based on the at least one first interior surface temperature obtained in step 100. Specifically, the surface temperature of other interior surfaces of the vehicle is obtained by correlating it with the at least one first surface temperature from step 100, which is obtained from a temperature sensor. This correlation takes into account the estimated solar absorption from step 102 and the estimated heat transfer by convection from step 104.

[0063] In step 108, the effect of the air conditioning system or the HVAC module 30 on heat transfer is determined. In one embodiment, the cabin air temperature module 62 estimates the heat flux from the HVAC module 30 in step 108 based on at least one parameter of the discharge air energy, such as the airflow rate and the air temperature. These parameters can be determined using one or more sensors of the HVAC module 30 or via the settings of the HVAC module.

[0064] In step 110, the cabin air temperature is estimated. In one embodiment, the change in thermal energy within the cabin is determined based on the net heat transfer by convection from the interior surfaces of the vehicle cabin 14, estimated in step 104, and the heat transfer from the HVAC module 30, estimated in step 102. The cabin air temperature can also be estimated based on the heat generated by the vehicle occupants. From the change in thermal energy, a change in cabin air temperature can be determined based on at least one known parameter relating to the air in the vehicle cabin 14, such as the air volume and air mass in the cabin. The change in cabin air temperature makes it possible to estimate the absolute cabin air temperature based on a previous estimate of the cabin air temperature.

[0065] In step 116, the estimated cabin temperature of the vehicle 12 is used to control at least one feature of a climate control system 32 of the vehicle 12. For example, the cabin air temperature provided by step 110 is used as feedback for the temperature control of the vehicle cabin 14 using the HVAC module 30, or the cabin air temperature is output via the dashboard 26, e.g., for viewing by a vehicle occupant, or both.

[0066] The estimation of heat transfer by convection from step 104 can yield a value per unit area. In this case, step 110 can estimate the change in cabin air temperature using the estimation of heat transfer by convection and known surface areas for the cabin interior surfaces stored in memory 35.

[0067] The vehicle cabin 14 can be divided into one or more virtual zones, so that the temperature of the cabin air can be determined separately for one or more virtual zones, especially for the front right side of the vehicle cabin 14, in which the driver sits.

[0068] Using the above-described methods for estimating the cabin temperature and the subsequent adjustment of the HVAC module 30, the desired cabin temperature can be precisely achieved and monitored in real time.

Claims

[1] Method for estimating the temperature of a vehicle cabin (14) and for using the estimated cabin temperature, the method comprising: Obtaining a surface temperature from a first interior surface of the vehicle cabin (14) via at least one temperature sensor (40); Estimating the surface temperature of a second interior surface using a value for heat transfer by solar radiation and a value for heat transfer by convection for the second interior surface as well as the surface temperature of the first interior surface of the vehicle cabin (14); Estimating the heat transfer from the first and second interior surfaces to the cabin air inside the vehicle cabin (14) using the surface temperature of the first and second interior surfaces via a processor; Estimating the cabin temperature of the vehicle (12) using at least the estimated heat transfer via a processor; Control at least one feature of a climate control system (32) of the vehicle (12) using the estimated cabin temperature; wherein the heat transfer is estimated using the respective heat transfer coefficients for the first and second inner surfaces and the respective surface temperature, wherein the respective heat transfer coefficient is determined as a function of the air flow rate of the air conditioning unit of the climate control (32). [2] Method according to claim 1, wherein the surface temperature is obtained based on an offset correction of a sensor reading from the temperature sensor (40). [3] Method according to claim 1, comprising using at least one solar load sensor to estimate the value of heat transfer by solar radiation, and / or using at least one known optical property of a vehicle window (18, 24) to estimate the value of heat transfer by solar radiation. [4] Method according to claim 1, wherein the cabin temperature is estimated using at least one known geometry of the vehicle cabin (14) and the estimated heat transfer, optionally retrieving the heat transfer coefficient using at least one of the vehicle speeds and at least one setting of the HVAC module (30) of the vehicle's HVAC (12).

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