Patent Application
20070131782
The present invention generally relates to onboard solar sensing systems for vehicle applications, and more particularly relates to an onboard solar sensing system that leverages real-time vehicle position data to generate accurate solar sensing data for one or more vehicle cabin locations.
Solar intensity information can be very useful in vehicle climate control (i.e., HVAC) systems. Intelligent onboard HVAC systems can use solar intensity data to adjust the outlet vent air temperature in the vehicle cabin, to control the routing of air in the vehicle cabin, to adjust the air velocity exiting the outlet vents, and to calculate the interior temperature of the vehicle. Conventional HVAC systems may employ a solar sensor mounted on the vehicle instrument panel such that the solar sensor receives solar energy that passes through the windshield of the vehicle. Such prior art solar sensors are utilized to help determine the light intensity entering the vehicle cabin, which may impact the settings of the HVAC system. For example, for a given ambient outside air temperature the HVAC system might generate relatively cooler air if the passengers are in the direct path of sunlight, and relatively warmer air if the passengers are not in the direct path of sunlight.
Existing HVAC systems having solar sensing capabilities are limited in that they do not adequately compensate for features of the vehicle that represent obstructions to sunlight. For example, window pillars may block the direct path of sunlight from the sun to the solar sensor, depending upon the time of day and the current orientation of the vehicle. These obstructions make the solar intensity measurements inaccurate and, therefore, can lead to unbalanced cooling/heating of the vehicle. Moreover, existing HVAC systems having solar sensing capabilities can be limited in that they do not accurately determine the solar conditions for each individual passenger location. Consequently, a multiple zone vehicle HVAC system that uses conventional solar sensing techniques does not adjust the climate for each passenger location based upon the localized solar conditions, or the HVAC system may require multiple solar sensors or a more complex single-solar sensor assembly, which can sense solar intensity in different directions, for each temperature zone in the vehicle.
Accordingly, it is desirable to have a system and method for generating real-time, accurate solar load information for a vehicle. In addition, it is desirable to have a system and method for generating solar load information suitable for adjusting a vehicle HVAC system, where the adjustments can account for the real-time positioning of the sun relative to the vehicle location and heading, while compensating for any sunlight obstructions associated with the vehicle design. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
An onboard system and method for generating solar load information for a vehicle is described herein. The system can be utilized to control the HVAC system for the vehicle. The system provides an accurate real-time estimation of the position of the sun relative to the current location and heading of the vehicle, and adjusts the HVAC system to compensate for the current solar intensity conditions in the vehicle. In practice, the system provides better climate control by considering the actual and real-time solar intensity experienced by the passengers.
The above and other aspects of the invention may be carried out in one form by a method for generating solar load information for a vehicle. The method involves: obtaining location data for the vehicle; obtaining current date/time data; resolving current sun position relative to the vehicle, based on the location data and the current date/time data, to generate sun correction data; obtaining solar intensity data from an onboard solar sensor; obtaining vehicle configuration data; and normalizing the solar intensity data based on the sun correction data and the vehicle configuration data, to generate at least one solar load value for the vehicle.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
The invention may be described herein in terms of functional and/or logical block components and various processing steps. It should be appreciated that such block components may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. For example, an embodiment of the invention may employ various integrated circuit components, e.g., memory elements, digital signal processing elements, logic elements, look-up tables, or the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that the present invention may be practiced in conjunction with any number of HVAC control protocols and that the HVAC system described herein is merely one exemplary application for the invention.
For the sake of brevity, conventional techniques related to solar sensors, temperature sensors, navigation, GPS systems, vehicle HVAC systems, and other functional aspects of the systems (and the individual operating components of the systems) may not be described in detail herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent example functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical embodiment.
The following description refers to elements or features being “connected” or “coupled” together. As used herein, unless expressly stated otherwise, “connected” means that one element/feature is directly joined to (or directly communicates with) another element/feature, and not necessarily mechanically. Likewise, unless expressly stated otherwise, “coupled” means that one element/feature is directly or indirectly joined to (or directly or indirectly communicates with) another element/feature, and not necessarily mechanically. Thus, although the schematic shown in
Vehicle 100 may include one or more light-obstructing structures, where the number, size, shape, and location of the light-obstructing structures will vary depending upon the particular configuration, design, style, and/or platform of vehicle 100. As used herein, a “light-obstructing structure” is any feature, element, component, or element of a vehicle that can potentially obscure, block, or interfere with the direct path of sunlight that would otherwise directly reach an onboard solar sensor. In this regard, six light-obstructing structures are depicted in
Depending upon the current location of vehicle 100, the current heading of vehicle 100 relative to true north, and the current position of the sun relative to vehicle 100, any of the light-obstructing structures (or any combination thereof) can block or interfere with the amount of direct sunlight reaching solar sensor 102. In the illustrated example where solar sensor 102 is mounted near the front of vehicle 100, the light-obstructing structures may block some of the sunlight when the sun is generally positioned within the dark zone shown in
A system and method for generating solar load information for a vehicle as described herein addresses the limitations of prior art systems by deriving accurate solar intensity information based upon solar sensor (and/or temperature sensor) data, vehicle location information, and sun position information. The technique may be realized in the form of a processing algorithm that uses vehicle heading, time, date, vehicle location, and primitive solar sensor data to obtain high precision solar intensity data relative to the vehicle position and the sun position. The system achieves such precision by calculating sun azimuth angle and sun zenith angle, and resolving the data against the existing vehicle data. The calculated solar load data can correspond to the various vehicle seating positions, and a total or overall solar load value may also be calculated for general HVAC and other vehicle uses.
Processor architecture 202 may be implemented or performed with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A processor may be realized as a microprocessor, a controller, a microcontroller, or a state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.
In practice, processor architecture 202 is suitably configured to control the operation of system 200 and to perform the various tasks described herein. In addition, processor architecture 202 may be configured to control the operation of other features, systems, and/or components of the vehicle in which system 200 is deployed. Although not separately depicted in
For simplicity, the following description assumes that system 200 employs only one solar sensor 204. In practice, however, system 200 can utilize any number of solar sensors 204. Solar sensor 204 is configured to provide sensor data indicative of solar energy for a particular measurement location on the vehicle; solar sensor 204 provides sensor data in a suitable format that can be understood and processed by processor architecture 202. In this regard, solar sensor 204 is preferably mounted in a fixed position on or in the vehicle. For example, solar sensor 204 may be mounted on the instrument panel as depicted in
In lieu of, or in addition to, solar sensor 204, system 200 may utilize temperature sensors 206 to obtain temperature data that is indicative of solar energy for a measurement location on the vehicle. Again, even though any number of temperature sensors 206 can be employed by a practical embodiment, the following description considers only one temperature sensor 206. Temperature sensor 206 is suitably configured to measure the local temperature at the measurement location. In practice, temperature sensor 206 may be realized as a thermistor, which can be mounted on the instrument panel, on the windshield, on the rear window, on the roof of the vehicle, on an external antenna of the vehicle, or the like. Temperature sensor 206 provides sensor data in a suitable format that can be understood and processed by processor architecture 202. As described in more detail below, system 200 processes the temperature data obtained from temperature sensor 206 and performs an energy balance to estimate the actual solar intensity at the measurement location. In other words, system 200 may be configured to derive the solar intensity information using temperature data rather than actual solar data.
Although not separately depicted in
Calendar/clock 208 may be any suitable source that provides current date and time data to system 200. In practice, calendar/clock 208 may be implemented in GPS receiver and/or in telematics system 214. Alternatively, calendar/clock 208 may be realized in connection with any subsystem of the vehicle. Calendar/clock 208 provides date/time data to system 200 in a suitable format that can be understood and processed by processor architecture 202.
Vehicle configuration data source 210 may be any suitable source that provides vehicle configuration data to system 200. As explained above, vehicle configuration data source 210 may be realized as a memory element, e.g., RAM memory. The vehicle configuration data includes data indicative of the physical layout, design, and topology of the vehicle in which system 200 is deployed. In a practical embodiment, the vehicle configuration data may include data indicative of: the vehicle model; the vehicle make; the vehicle model year; the vehicle body dimensions; the locations of the vehicle windows; the locations of any light-obstructing structures; the glass type or composition of each window; glass thickness; locations of occupant seating surfaces; and any information necessary for the operation of system 200, such as the number of separate temperature-controlled zones in side of the vehicle. Vehicle configuration data source 210 provides the vehicle configuration data in a suitable format that can be understood and processed by processor architecture 202.
The location data source is suitably configured to provide current location data for the vehicle in which system 200 is deployed. The location data source provides the location data in a suitable format that can be understood and processed by processor architecture 202. In one practical embodiment, the location data source is telematics system 214. In this context, telematics system 214 is an onboard system that obtains various types of information from one or more data sources (which may be onboard or external sources) for processing, presentation to the operator, etc. For example, a practical telematics system may handle navigation data, ONSTAR system data, telephone data, satellite radio data, and/or satellite video data. Telematics system information may comprise or be derived from: GPS data; vehicle heading data; mapping software data; downloaded data; climate data; solar intensity data; ambient temperature data; weather data; or the like. In the context of system 200, telematics system 214 may provide the current vehicle location in terms of longitude and latitude measurements, the current vehicle heading in an absolute measurement (e.g., north, north-west, south-east, or the like), and/or the current vehicle angular heading relative to true north.
In another practical embodiment, the location data source is GPS receiver 212, which may be a commercial civilian grade receiver. In accordance with known methodologies and techniques, GPS receiver 212 obtains GPS data corresponding to the GPS antenna location on the vehicle. The GPS data may indicate the current vehicle location in terms of longitude and latitude measurements, the current vehicle heading in an absolute measurement (e.g., north, north-west, south-east, or the like), and/or the current vehicle angular heading relative to true north. GPS receiver 212 may also provide system 200 with the current date, the current time, the current time zone, and other pertinent information. In practice, GPS receiver 212 may provide the GPS data to other onboard vehicle systems, such as a navigation system.
As described in more detail below, processor architecture 202 is generally configured to process the current location data for the vehicle, along with the current data/time data, to resolve the current sun position relative to the vehicle. For example, processor architecture 202 may calculate sun azimuth and/or sun zenith. In this regard,
In this example, HVAC control element 218 is designed to accommodate zoned operation of an onboard HVAC system (not shown). In other words, the HVAC system has multiple zones that are independently controllable. In practice, a multi-zone vehicle HVAC system may have separate controls for different passenger seating locations. As depicted in
HVAC control process 600 begins by obtaining data (task 602) from one or more data sources. Such data may include, without limitation: solar intensity data 604 from one or more solar sensors; temperature data 606 from one or more temperature sensors; GPS data 608, which includes location data for the vehicle; telematics system data 610, which includes location data for the vehicle; and other vehicle data 612 (e.g., current date/time data, vehicle configuration data, onboard compass data, and vehicle velocity). Temperature data 606 may include the temperature of a measurement location on or in the vehicle, which is utilized for energy balancing as described below, the outside ambient air temperature, and/or the vehicle cabin air temperature.
HVAC control process 600 may calculate the sun azimuth angle (task 614) and the sun zenith angle (task 616) from the current date/time data and the current vehicle location data. In practice, process 600 may perform a “reverse sextant” technique to determine the azimuth and zenith angles. In addition, process 600 may resolve the current sun position relative to the vehicle (task 618) to generate sun correction data. In the example embodiment, process 600 resolves the current sun position against the current vehicle heading and true north, using the current vehicle location data, the current date/time, the sun azimuth angle, and the sun zenith angle. The resulting sun correction data enables the system to generate a real-time and accurate estimate of the actual solar intensity levels of the vehicle.
In one example embodiment, HVAC control process 600 normalizes the solar intensity data (task 620) based on the sun correction data and the vehicle configuration data. During task 620, process 600 compensates for the presence of any light-obstructing structures that may impact the solar intensity measured by the solar sensor(s). In other words, task 620 transforms the solar intensity data to produce accurate solar intensity estimates for one or more locations in the vehicle.
In an alternate embodiment, HVAC control process 600 calculates estimated solar intensity values based on the temperature data, the sun correction data, and the vehicle configuration data. In other words, process 600 derives solar intensity information from temperature data rather than calculating solar intensity information from a direct solar sensor measurement. In particular, process 600 may calculate the solar intensity based on an interior temperature energy balance technique (task 622, which is shown in dashed lines to indicate its optional nature). The energy balancing obtains an estimated solar intensity corresponding to the measurement location from which the temperature data was obtained. Notably, the energy balance and the estimated solar intensity may also be influenced by the measured inside air temperature of the vehicle, the measured outside ambient air temperature, the measured current velocity of the vehicle, and/or other conditions.
where
Ksol
Tsurr=f(Tambient, vehicle13 speed, Tair); and
HA=f(air13 delivery_method, HVAC_system_airflow)
Of course, the particular energy balance methodology may vary according to the specific system configuration and location of temperature sensor. For example, in lieu of a temperature sensor mounted to the vehicle instrument panel, the system may include a temperature sensor mounted directly to the windshield for measurement of the glass temperature. In this alternate embodiment, the solar intensity would be based on an energy balance around the measured glass temperature. As another example, in lieu of a temperature sensor mounted to the vehicle instrument panel, the system may include a temperature sensor mounted directly to the roof sheet metal for measurement of the inner surface temperature. In this alternate embodiment, the solar intensity would be based on an energy balance around the measured sheet metal temperature.
Whichever solar intensity estimation technique is employed, HVAC process 600 ultimately generates at least one solar load value for the vehicle (task 624). In the practical embodiment, these solar load values represent control signals for the vehicle HVAC system. In this regard, process 600 may adjust operation of the onboard HVAC system in response to the solar load values (task 626). For a multi-zone HVAC system, task 624 generates a plurality of positional solar load values for the vehicle (and possibly a total solar load value for the vehicle), where each positional solar load value corresponds to a particular passenger location of the vehicle. For such an embodiment, task 626 adjusts the zoned operation of the HVAC system in response to the individual positional solar load values (and possibly in response to a total solar load value). In a practical implementation, the solar load values can influence one or more functions of the HVAC system, including, without limitation: fan speed; output air temperature; airflow mode (e.g., upper vents, lower vents, defrost); selection of fresh versus recirculating air.
Following task 626, HVAC control process 600 can be re-entered at task 602, thus forming a continuous loop that represents an ongoing procedure. The technique described herein enables precise solar load estimation for the vehicle at all times regardless of vehicle location and regardless of the position of the sun relative to the vehicle. The HVAC system control technique can be utilized to provide solar compensation for multiple zones within the vehicle. Moreover, the control technique can provide sunrise and sunset correction, and solar filtering for tunnel, garage, and other covered environments.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
