Vehicle humidifier system

A humidifier system for a vehicle passenger cabin includes an onboard humidifier, an onboard reservoir in fluid communication with the humidifier and adapted to collect a fluid from a vehicle heat exchanger, and a controller configured to determine at least a passenger cabin relative humidity value and a dew point value for at least one vehicle window. The controller is configured to actuate the onboard humidifier to provide a humidified airflow into the passenger cabin, and to actuate a window heating system to heat the at least one vehicle window sufficiently to prevent or remove fogging resulting from the humidified airflow. Methods for controlling the humidifier system are described.

TECHNICAL FIELD

The present disclosure generally relates to onboard humidifier systems for vehicles. More specifically, the present disclosure relates to an onboard vehicle humidifier system which helps to maintain a desired passenger cabin humidity level and concurrently prevents vehicle window fogging/frosting when the passenger cabin humidity level is increased.

BACKGROUND

During certain climatic conditions, vehicle passenger cabin humidity may decrease below percentages providing an acceptable comfort level to vehicle passengers. As a non-limiting example, a room in a home kept at 70° F. is considered comfortable to an occupant at a relative humidity of 40-50%. Below that relative humidity, skin may dry and become itchy and mucosal membranes and eyes may feel dry and irritated. Similar phenomena may occur during exposure to a passenger cabin held at a below-optimal relative humidity for extended periods of time, for example during a long road trip.

This is known to occur in dry, cold seasons such as winter and in arid regions. For example, in cooler temperatures a vehicle passenger cabin humidity level may decrease to uncomfortable levels because vehicle-exterior air contains less moisture than the passenger cabin interior air. In turn, in a vehicle windows (front and rear windshield, side windows, etc.) are exposed to the ambient temperatures and are therefore colder than the passenger cabin interior. This creates a low dew point for the window that creates fog/frost. To counter this phenomenon, conventionally window defroster/defogger systems are provided which prevent or remove fog/frost from windows by directing a heated airflow against the window interior surface. While effective in countering window fog/frost, the airflow blown against the window interior surface is typically dry, resulting in the unintended consequence of further drying the passenger cabin air and further lowering the passenger cabin interior relative humidity.

This could be solved by simply incorporating a stand-alone or built-in humidifier into the vehicle's climate control accessories. However, this would require the user to perform additional tasks, such as ensuring that the stand-alone humidifier water supply was kept adequately supplied. In turn, the user would need to monitor vehicle window fog/frost status to prevent fogging/frosting during humidifier use.

Accordingly, there is identified a need in the art for methods and systems for supplementing traditional vehicle climate control systems, in particular for increasing passenger cabin relative humidity when and if needed. The methods and systems should require minimal user input, and further should contemplate issues of window fogging/frosting prevention during humidifier use.

SUMMARY

In accordance with the purposes and benefits described herein, in one aspect of the present disclosure a humidifier system for a vehicle passenger cabin is provided, comprising an onboard humidifier, an onboard reservoir in fluid communication with the humidifier and adapted to collect a fluid from a vehicle heat exchanger, and a controller configured to determine at least a passenger cabin relative humidity value and a dew point value for at least one vehicle window. The controller may be further configured to actuate the onboard humidifier to provide a humidified airflow into the passenger cabin for a sufficient time to adjust a passenger cabin relative humidity from the determined passenger cabin relative humidity value to a predetermined passenger cabin relative humidity threshold value.

The controller may be further configured to concurrently or sequentially actuate a window heating system to heat the at least one vehicle window sufficiently to prevent or remove fogging resulting from the humidified airflow. In embodiments, the controller controls an amount of heat applied to the at least one vehicle window by the window heating system according to the adjusted passenger cabin relative humidity and the determined dew point for the at least one vehicle window. Still more, the controller may be further configured to determine an amount of fluid collected in the onboard reservoir.

In embodiments, the humidified airflow may be directed into the passenger cabin through an inlet selected from one or more of a dash panel-mounted air register, a headliner-mounted air vent, a steering wheel-mounted air vent, and a hose and mask apparatus adapted to be worn by a vehicle passenger. In embodiments, the humidifier system may be adapted for manual actuation and/or for automatic actuation by the controller in accordance with the determined passenger cabin relative humidity value.

In another aspect of the disclosure, a method for providing humidified air to a passenger cabin of a vehicle is described, comprising providing an onboard humidifier system as summarized above, determining whether a humidity level of the passenger cabin is less than a predetermined threshold humidity level, and by the described controller, actuating the humidifier to provide a humidified airflow into the passenger cabin and actuating the window heating system to heat the at least one vehicle window sufficiently to prevent or remove frost and/or fog. In embodiments, the method includes actuating the humidifier until the humidity level of the passenger cabin is raised to the predetermined threshold humidity level. The method may further include, by the controller, determining an amount of fluid collected by the reservoir.

In embodiments, the method includes configuring the controller to receive inputs from one or more passenger cabin humidity sensors and from one or more window interior temperature sensors. The method may further include configuring the controller to determine the dew point for the at least one vehicle window from the inputs from the one or more passenger cabin humidity sensors and the one or more window interior temperature sensors. In embodiments, the method includes setting the predetermined threshold humidity level at a relative humidity of 60%. In embodiments, the method includes, by the controller, adjusting an amount of heat supplied by the window heating system according to the adjusted passenger cabin humidity level and the determined dew point for the at least one vehicle window.

In certain embodiments, the method includes manually actuating the humidifier system. In alternative embodiments, the method includes, by the controller, automatically actuating the humidifier system when the amount of fluid collected in the reservoir is determined by the controller to be at or above a predetermined minimum volume and the inputs provided to the controller by the one or more passenger cabin humidity sensors indicate that the passenger cabin humidity level is below the predetermined threshold humidity level. The method may further include, by the controller, automatically actuating the window heating system when the determined window dew point is above a predetermined dew point threshold.

In the following description, there are shown and described embodiments of the disclosed humidifier system for a vehicle, and methods for use thereof. As it should be realized, the described systems and methods are capable of other, different embodiments and their several details are capable of modification in various, obvious aspects all without departing from the systems and methods as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.

Reference will now be made in detail to embodiments of the disclosed vehicle onboard humidifier system, examples of which are illustrated in the accompanying drawing figures.

DETAILED DESCRIPTION

The present disclosure is directed to an onboard humidifier system for a vehicle that can be used to increase a relative humidity of the vehicle passenger cabin while accounting for the tendency of the vehicle windows to frost or fog at higher passenger cabin relative humidity. At a high level, the described onboard humidifier system reclaims water condensation generated by other vehicle systems such as the heating, ventilation, and air-conditioning (HVAC) system, stores the reclaimed water in a reservoir, and pumps the reclaimed water to a humidifier. At need, HVAC air is directed over the humidifier to increase the relative humidity thereof, and then the humidified airflow is directed into the vehicle passenger cabin to improve passenger comfort. Concurrently or sequentially, a window heating system controls a dew point of the vehicle windows to prevent fogging/frosting.

With reference toFIG. 1, a vehicle100includes a passenger cabin102and a plurality of windows104a,104b,104c, . . . ,104x(in the depicted embodiment, the windshield104a, driver's side windows104b, and rear windshield104care shown). The vehicle100further includes an onboard humidifier system106, which as summarized above is adapted to reclaim water condensation generated by systems such as the HVAC system, and use that reclaimed water condensation to generate humidified air which can be provided to the passenger cabin102interior. The vehicle may be an electric vehicle as shown, including a power plug108adapted for connection to a power source (not shown) to charge a battery (not shown) that provides the primary power source for the vehicle. However, it will be appreciated that the described onboard humidifier system106is equally readily adaptable to any vehicle100type, including vehicles powered by combustion engines, hybrid electric-combustion engine vehicles, and others.

In more detail, with reference toFIG. 2the onboard humidifier system106is associated generally with the vehicle HVAC system (shown generally as reference numeral110). The components of a vehicle HVAC system110are well known in the art, and are not described in detail herein. Specifically, in the depicted embodiment the onboard humidifier system106includes a reservoir112adapted to collect water condensation/runoff from a vehicle heat exchanger114, in the depicted embodiment being the air conditioner (AC) condenser. The reservoir includes a dump valve116in fluid communication with an overflow line118leading to a filtration system (not shown). Heating coils120may be included for heat-cleaning the collected water condensation. A similar water reclamation system is disclosed in greater detail in U.S. Published Patent Appl. No. 20160083936 to the present Assignee, Ford Global Technologies, LLC, the entirety of the disclosure of which is incorporated herein by reference as if fully reproduced. A pump122moves reclaimed water condensation via a line124placing the reservoir112in fluid communication with a humidifier126. In the depicted embodiment the humidifier126includes a humidifying wick device128, although alternative humidifier designs are contemplated.

Line130transports a humidified airflow from the humidifier126to one or more inlets132. In the depicted embodiment, the inlets may be one or more of a dash panel131-mounted air register132a, a steering wheel134-mounted air duct132b, a roof panel or headliner-mounted air duct132c, for example an air duct132cassociated with an overhead console (seeFIG. 1), and a hose and mask apparatus132dadapted to be worn by a user (not shown) to provide humidified air directly to the user. A return line136returns dry air to the HVAC system110, in the depicted embodiment returning air to the AC condenser114.

Returning toFIG. 1, the onboard humidifier system106may further include one or more sensors. In the depicted embodiment, the sensors include one or more onboard passenger cabin humidity sensors138(use of alternative sensors such as hygrometers and others is contemplated), one or more passenger cabin temperature sensors140, and one or more exterior ambient temperature sensors142. The onboard humidifier system106may further comprise one or more vehicle window interior temperature sensors144. As will be appreciated, the window interior sensors144may be directly associated with an interior surface of each window104a,104b,104c, . . . ,104x, or may comprise one or more remotely positioned infrared sensors.

The sensors are configured to provide inputs to one or more controllers146by wired or wireless means represented by dashed lines. As will be appreciated, any number of suitable microprocessor-based controllers146are contemplated, including without intending any limitation a centralized controller such as the vehicle Body Control Module (BCM), an HVAC controller, one or more other dedicated Electronic Control Units (ECU), or combinations.

In turn, the onboard humidifier system106includes a window104defrost/defog system150. As will be appreciated, the defrost/defog system150which may comprise one or more air ducts150aadapted to direct a heated airflow against an interior of a window104to prevent or remove frost/fog, may be an infrared window heater150bdirectly associated with a window104, or may be another type of window heating system such as heating coils or wires (not shown) embedded within one or more windows.

Use of the onboard humidifier system106will now be described with reference toFIG. 3illustrating a humidifier system control method200. As will be appreciated, storing fluids such as water condensate for extended periods of time in a hot and potentially humid environment such as a vehicle100engine compartment presents a risk of contamination, for example by particulates and debris, mold, fungi, etc. Accordingly, as is described in greater detail in U.S. Published Patent Appl. No. 20160083936, provision is made for monitoring an amount of time water is stored in the reservoir112and for cleaning/renewing the stored water supply. At step202, controller146is configured to monitor a time of storage of water condensate in reservoir112. In one possible embodiment, a timer (not shown) associated with either the reservoir112or the controller146is started when the reservoir is filled. As will be described, the controller146is further configured to cause the contents of the reservoir112to be discarded if not passed to the humidifier126within a predetermined time period. In one possible embodiment, the predetermined time period may be 12 hours, although of course any suitable time period is contemplated.

At step204, the controller146queries the system to determine if the AC condenser114is operating. If so, at step206the controller146actuates pump122to transfer water condensate from the AC condenser114to the reservoir112via line124. If not, the system proceeds to the next step.

Next, a flush/clean step is provided. At step208the controller146determines whether water is present in the reservoir112and/or the humidifier126. This may be via input provided from a water level sensor113such as an electronic sensor, a simple mechanical float, or other suitable device for determining a water level in the reservoir112and/or the humidifier126. If so, at step210water is drained from the humidifier126via a drain line148(seeFIG. 2) which passes the water to the vehicle100exterior.

If not, at step212the controller146determines whether the water contained in the reservoir112has been stored for more than the predetermined time period. If so, at step214the reservoir is drained by way of dump valve116(seeFIG. 2). If not, at step216the controller146determines whether conditions requiring passage of water stored in reservoir112to the humidifier126have been detected. If not, the system returns to step202. If so, at step218water is transferred to the humidifier126via pump122/line124. The water may be passed through a filter (not shown) prior to entry to the humidifier126to remove particulates, debris, etc.

At step220, the controller146receives inputs from the one or more onboard passenger cabin humidity sensors138to determine a relative humidity level of the passenger cabin102. If the determined relative humidity level if the passenger cabin102is above a predetermined threshold determined to provide satisfactory comfort to a passenger, the relative humidity level monitoring continues (step222). If the passenger cabin relative humidity level is determined to have fallen below the predetermined threshold, at step224the humidifier126is actuated by the controller146, and a humidified airflow is passed into the passenger cabin102by way of lines130/inlets132(seeFIG. 2).

Simultaneously or sequentially, at step226the controller146receives inputs from the one or more passenger cabin temperature sensors140, one or more exterior ambient temperature sensors142, and one or more vehicle window interior temperature sensors144. From these inputs, the controller146calculates a window104fog/dew point and/or fog/dew level. If the calculated window104fog/dew point and/or fog/dew level is determined to be within a predetermined threshold whereby visibility is not considered impaired or at risk of impairment, the system returns to step202. On the other hand, if the calculated window104fog/dew point and/or fog/dew level is not within the predetermined threshold, the controller146actuates the window defrost/defog system150to prevent or remove frosting/fogging from one or more windows104.

In an embodiment, a rate of heat provided by the defrost/defog system150is determined by the controller146in accordance with the amount of humidity provided as humidified air from the humidifier126and according to a defogging algorithm.

Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.