Patent Application
20170297412
The disclosure generally relates to a method of controlling an HVAC system of a vehicle.
Most vehicles include a Heating Ventilation Air Conditioning (HVAC) system that is at least operable in a defrost mode and/or a cabin heating mode. When controlled to operate in the defrost mode, the HVAC system directs a flow of heated air directly onto an interior surface of the windows to dissipate frost that may have formed on an exterior surface of the windows, and/or dissipate condensation that may have formed on an interior surface of the window. When controlled to operate in the cabin heating mode, the HVAC system directs a flow of heated air into a passenger cabin of the vehicle to warm the air within the passenger cabin to a desired cabin temperature. The HVAC system may also be controlled to operate in a split mode, in which both the defrost mode and the cabin heating mode are simultaneously applied. In so doing, a portion of the flow of heated air is directed onto the windows to defog/defrost the windows, and another portion of the flow of heated air is directed into the cabin to heat the cabin air to the desired cabin temperature.
A method of controlling a Heating Ventilation Air Conditioning (HVAC) system of a vehicle is provided. The method includes repeatedly sensing an area of a window of the vehicle that is not covered by frost with a sensor positioned adjacent the window. When the sensed area not covered by frost is less than an area threshold value, a HVAC controller controls the HVAC system to operate in a defrost mode. When the sensed area not covered by frost is equal to or greater than the area threshold value the HVAC controller controls the HVAC system to operate in a cabin heating mode. The HVAC controller automatically switches the HVAC system from the defrost mode to the cabin heating mode when the sensed area not covered by frost increases to a value that is equal to or greater than the area threshold value.
A vehicle is also provided. The vehicle includes a body defining a passenger cabin, and including a window. The vehicle further includes a HVAC system that is operable in a defrost mode for defrosting the window, or in a cabin heating mode for heating the passenger cabin. An optical sensor is positioned adjacent the window, within the passenger cabin. The optical sensor is operable to sense light through the window. A light source is attached to the body, outside of the passenger cabin, and is positioned to emit light through the window. A HVAC controller is disposed in communication with the optical sensor, such that the optical sensor is operable to sense data related to light emitted from the light source and transmitted through the window, and communicate the sensed data to the HVAC controller. The HVAC controller includes a processor and tangible, non-transitory memory on which are recorded computer-executable instructions, including an HVAC control algorithm. The HVAC control algorithm is operable on the processor to calculate a percentage of the window that is covered by frost, based on the sensed data received from the optical sensor. The HVAC control algorithm automatically controls the HVAC system to operate in one of the defrost mode or the cabin heating mode based on the calculated percentage of the window covered by frost.
Accordingly, the HVAC controller receives data from the sensor adjacent the window, and uses that data to calculate a percentage of the window that is covered by frost. The HVAC controller then automatically determines whether to operate the HVAC system in the defrost mode or the cabin heating mode based on the calculated percentage of the window not covered by frost. As the calculated percentage changes, i.e., increases, to a percentage equal to or greater than the area threshold value, then the HVAC controller may automatically switch the operation of the HVAC system from the defrost mode to the cabin heating mode. By automatically switching the HVAC system from the defrost mode to the cabin heating mode as soon as the window has been defrosted to an appropriate degree, instead of allowing the defrost mode to operate for a period of time after the window has been defrosted, thermal energy is directed to warming the cabin air more quickly, thereby reducing the time required to heat the cabin air to the desired cabin temperature.
The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the teachings when taken in connection with the accompanying drawings.
Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions.
Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a vehicle is generally shown at 20 in
The vehicle 20 further includes a Heating Ventilation Air Conditioning (HVAC) system 28. The HVAC system 28 includes, but is not limited to, a fan 29 for moving a flow of air through a system of ducts 30, a heating core 32 for exchanging heat from an engine coolant to the flow of air, and an evaporator (not shown) for removing heat from the flow of air. The system of ducts 30 includes one or move valves, flaps, or other similar control devices to control the flow of air between different outlets. For example, the system of ducts 30 includes at least one defrost outlet 34 disposed adjacent the window 26 for directing the flow of air directly onto the window 26. The system of ducts 30 also includes at least one cabin outlet 36 positioned to direct the flow of air into the passenger cabin 24 for heating and/or cooling the air within the passenger cabin 24.
The HVAC system 28 is operable in at least a defrost mode and a cabin heating mode. It should be appreciated that the HVAC system 28 may be operable in other modes not described herein. When the HVAC system 28 is controlled to operate in the defrost mode, the system of ducts 30 directs the flow of air through the heating core 32 to draw heat from an engine coolant, and then direct the flow of heated air onto the window 26, generally indicated by arrow 38, to either defrost an exterior surface of the window 26, and/or defog an interior surface of the window 26. When the HVAC system 28 is controlled to operate in the cabin heating mode, the system of ducts 30 directs the flow of air through the heating core 32 to draw heat from the engine coolant, and then directs the flow of heated air into the passenger cabin 24, generally indicated by arrow 40, for heating the passenger cabin 24 to a desired cabin temperature. The cabin heating mode may include any HVAC operating mode that does not directly direct a flow of air onto the window 26 for the purpose of defrosting the window 26. For example, the cabin heating mode may direct the flow of heated air toward a passenger foot area through a lower outlet, or toward a passenger torso area through a panel or dash mounted outlet. It should be appreciated that the cabin heating mode may include other heating mode options that are not specifically noted or described herein. The HVAC system 28 may be operated in a split mode, in which a portion of the flow of heated air is directed onto the window 26, i.e., the defrost mode, and another portion of the flow of heated air is simultaneously directed into the passenger cabin 24, i.e., the cabin heating mode.
The vehicle 20 further includes a sensor 42. The sensor 42 is positioned adjacent the window 26, within the passenger cabin 24. In an exemplary embodiment, the sensor 42 is operable to sense light and/or objects through the window 26. In the exemplary embodiment shown in
If the sensor 42 is a light sensor 42, it may be necessary to equip the vehicle 20 with a light source 44 that is attached to the body 22, outside of the passenger cabin 24, and positioned to emit light through the window 26, into the interior of the passenger cabin 24 and onto the sensor 42, so that the sensor 42 may detect the light passing through the window 26. For example, if the sensor 42 is an infrared light sensor 42, an infrared light source 44 may be placed outside the passenger cabin 24 to shine through the window 26. Such an optical sensor 42 would be operable to sense data related to the light emitted from the light source 44, and transmitted through the window 26.
The vehicle 20 further includes a HVAC controller 46. The HVAC controller 46 is disposed in communication with the sensor 42, with the sensor 42 communicating sensed data to the HVAC controller 46. The HVAC controller 46 is operable to control the HVAC system 28, at least partially on the data sensed by the sensor 42. The HVAC controller 46 may include a computer and/or processor, and include all software, hardware, memory, algorithms, connections, sensor 42s, etc., necessary to manage and control the operation of the HVAC system 28. As such, a method, described below and generally shown in
The HVAC controller 46 includes a tangible non-transitory memory having computer executable instructions recorded thereon, including a HVAC control algorithm. The controller further includes a processor that is operable to execute the HVAC control algorithm to control the HVAC system 28 between the defrost mode, the cabin heating mode, and/or the split mode. The HVAC control algorithm uses the data from the vehicle sensor(s) 42 to determine the percentage of the window 26 that is covered by frost, and control the HVAC system 28 between the defrost mode and the cabin heating mode based on the percent of the window 26 covered by frost.
The HVAC controller 46 may be embodied as one or multiple digital computers or host machines each having one or more processors, read only memory (ROM), random access memory (RAM), electrically-programmable read only memory (EPROM), optical drives, magnetic drives, etc., a high-speed clock, analog-to-digital (A/D) circuitry, digital-to-analog (D/A) circuitry, and any required input/output (I/O) circuitry, I/O devices, and communication interfaces, as well as signal conditioning and buffer electronics.
The computer-readable memory may include any non-transitory/tangible medium which participates in providing data or computer-readable instructions. Memory may be non-volatile or volatile. Non-volatile media may include, for example, optical or magnetic disks and other persistent memory. Example volatile media may include dynamic random access memory (DRAM), which may constitute a main memory. Other examples of embodiments for memory include a floppy, flexible disk, or hard disk, magnetic tape or other magnetic medium, a CD-ROM, DVD, and/or any other optical medium, as well as other possible memory devices such as flash memory.
The HVAC controller 46 includes a processor and tangible, non-transitory memory on which are recorded computer-executable instructions, including the HVAC control algorithm. The HVAC control algorithm implements the method of controlling the HVAC system 28 described below. Referring to
In another example, the sensor 42 may be configured or programmed to sense data related to a boundary line 52 at the edge of intersections between portions of the window 26 that are covered by frost and portions that are not covered by frost. The HVAC controller 46 may then use the data related to the sensed boundary line 52 to determine a size of the area of the window 26 that is or is not covered by frost. In yet another alternative embodiment, the sensor 42 may be configured to sense or detect objects, such as a hood or body 22 line of the body 22. The HVAC controller 46 may then be able to determine the size of the area of the window 26 that is covered by frost based on the amount of the hood/vehicle 20 body 22 that is visible through the window 26 to the sensor 42, through the un-frosted regions of the window 26. It should be appreciated that the data sensed by the sensor 42, and the manner in which the sensor 42 and/or the HVAC controller 46 determines the amount of the window 26 that is covered by frost and is not covered by frost may differ from the exemplary embodiments described herein.
Once the sensor 42 has sensed the data related to the area of the window 26 that is and is not covered by frost, then the HVAC controller 46 may calculate a percentage of the window 26 that is not covered by frost, based on the data sensed by the sensor 42 related to the area of the window 26 not covered by frost. Calculating the percentage of the window 26 not covered by frost is generally indicated by box 102 in
A temperature of the engine coolant is also continuously or repeatedly sensed with a coolant temperature sensor 42 of the vehicle 20. Sensing the engine coolant temperature is generally indicated by box 104 in
The HVAC controller 46 then compares the sensed temperature of the engine coolant to a coolant threshold temperature to determine if the temperature of the engine coolant is less than the coolant threshold temperature, or if the temperature of the engine coolant is equal to or greater than the coolant threshold temperature. The coolant threshold temperature is a pre-defined temperature that the engine coolant should reach prior to being used for heating the flow of air circulating through the HVAC system 28. Prior to the engine coolant reaching the coolant threshold temperature, all of the heat within the engine coolant should be directed toward warming the engine, and not used to warm the flow of air through the HVAC system 28. For example, the coolant threshold temperature may be defined to equal a temperature of approximately 20° C.
A cabin temperature within the passenger cabin 24 of the vehicle 20 is also continuously and/or repeatedly sensed with an air temperature sensor 42. Sensing the cabin temperature is generally indicated by box 106 in
The HVAC controller 46 compares the percentage of the window 26 not covered by frost to an area threshold value, to determine if the percentage of the window 26 not covered by frost is less than or equal to the area threshold value, or if the percentage of the window 26 covered by frost is greater than the area threshold value. The area threshold value is a minimum area of the window 26 that must be cleared of frost or fog before the HVAC fully switches to the cabin heating mode. For example, the area threshold value may be defined to equal between 50% and 100% of the total area of the window 26. The area threshold value may be a user defined value that is input into the HVAC controller 46, or may be a pre-defined value programmed into the HVAC controller 46.
As generally indicated at box 108 in
If the HVAC controller 46 determines that the sensed cabin temperature is not less than the desired cabin temperature, the percentage of the window not covered by frost is not less than the area threshold value, and/or the sensed temperature of the engine coolant is not less than the coolant threshold temperature, generally indicated at 112, then the HVAC controller 46 determines if the sensed cabin temperature is less than the desired cabin temperature, the percentage of the window not covered by frost is less than the area threshold value, and the sensed temperature of the engine coolant is equal to or greater than the coolant threshold temperature, generally indicated by box 114 in
So long as the percentage of the window 26 that is not covered by frost is less than the area threshold value, the HVAC controller 46 controls the HVAC system 28 to operate in the defrost mode. However, if the HVAC controller 46 determines that the sensed cabin temperature is not less than the desired cabin temperature, the percentage of the window not covered by frost is not less than the area threshold value, and/or the sensed temperature of the engine coolant is not equal to or greater than the coolant threshold temperature, generally indicated at 120, then the HVAC controller compares the sensed area that is not covered by frost to an intermediate area threshold value, generally indicated at 122. The intermediate area threshold value may be defined to equal a value between 10% and 90% of a total area of the window 26. If the HVAC controller 46 determines that the sensed area not covered by frost is equal to or greater than the intermediate area threshold value, but is less than the area threshold value, that the temperature of the engine coolant is equal to or greater than the coolant threshold temperature, and the sensed cabin temperature is less than the desired cabin temperature, generally indicated at 124, then the HVAC controller 46 may control the HVAC system 28 to operate in the split mode, i.e., to operate both the defrost mode and the cabin heating mode simultaneously, generally indicated by box 126. In so doing, once the window 26 begins to and is partially defrosted, a portion of the heated flow of air may be directed to heating the passenger cabin 24.
When the sensed area not covered by frost is equal to or greater than the area threshold value, and the air temperature within the passenger cabin 24 is less than the desired cabin temperature, the HVAC controller 46 controls the HVAC system 28 to operate in the cabin heating mode, with the fan 29 at 100% duty cycle, to heat the air within the cabin, generally indicated by box 128. The HVAC operates the HVAC system 28 in the cabin heating mode until the air temperature within the passenger cabin 24 reaches the desired cabin temperature, at which time the HVAC controller 46 controls the fan 29 to operate at a lower duty cycle, for example, a 25% duty cycle, generally indicated by box 130, until the user enters a command into the HVAC controller 46 to alter the control scheme.
The HVAC controller 46 automatically switches the HVAC system 28 from the defrost mode to the cabin heating mode when the sensed area not covered by frost increases to a value that is equal to or greater than the area threshold value. Accordingly, the switch from the defrost mode to the cabin heating mode is not based on a pre-set time, at which the window 26 may or may not be defrosted. Rather, the decision to switch from the defrost mode to the cabin heating mode is based on the current, actual conditions of the window 26. By so doing, the HVAC system 28 operates in the defrost mode only long enough to defrost the window 26, and does not spend extra time directing heated air onto the window 26 after the window 26 has been defrosted. By automatically switching from the defrost mode to the cabin heating mode when the sensed area not covered by frost is a value that is equal to or greater than the area threshold value, heat may be more quickly directed toward warming the air within the passenger cabin 24.
The method described above is particularly useful to vehicles 20 including remote start capabilities, in which the vehicle 20 may be remotely started from a portable hand held device, such as a key fob, a smart phone, tablet, or other mobile device. The HVAC controller 46 may be linked to and in communication with the portable hand held device such that the vehicle 20 may be remotely started and a desired cabin temperature may be input into the HVAC controller 46 via the portable hand held device. In so doing, a user may define the temperature they wish the passenger cabin 24 to be heated to. The HVAC controller 46 will control the HVAC system 28 as described above to first defrost the window 26, for example, the front windshield, and then automatically switch to the cabin heating mode to heat the passenger cabin 24 to the desired cabin temperature when the window 26 is defrosted. The process described above minimizes the amount of time required to defrost the window 26 and heat the passenger cabin 24 to the desired cabin temperature.
The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed teachings have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims.
