Multi-passenger vehicle ventilation system

A ventilation system for a vehicle having a cabin includes a segmented plenum comprising a plurality of sub-plenums that are disposed above the cabin, a perforated panel defining the ceiling of the cabin and having plurality of perforations for air communication of the plenum with the cabin, and ductwork including one or more upper main ducts, lower main ducts, vertical ducts, and seat return ducts. The ducts communicate with each other to convey air, descending from the segmented plenum through the perforated panel as a high volume, low turbulence blanket of air through the cabin, back to the segmented plenum. The ventilation system also includes an air processing unit (APU) in communication with the ductwork and operable to sterilize the air conveyed therein, and one or more fans for circulating the air in the ventilation system.

TECHNICAL FIELD

The present disclosure relates generally to ventilation systems, and more particularly, to multi-passenger vehicle ventilation systems.

BACKGROUND

In the wake of the Covid-19 pandemic, governments spent billions of dollars and there are still unspent billions to address making public places and services, such as transportation, safer. While schools may have been made safer with increased air exchange, children are still spending extended periods of time on school buses sneezing, coughing, and discharging respiratory droplets (e.g., spitting) on each other while traveling to and from school. To fully protect our children and their safety this school bus exposure needs to be addressed.

Similarly, in public transportation, public buses ferrying passengers daily to and from jobs and on innumerable short and long term trips expose the passengers to unnecessary risk by intermixing the air they breathe and distributing any germs and biological material among, contributing to spread of respiratory and other diseases, including Covid-19. Occupants of other confined spaces, and particularly vehicles such airplanes, boats, vans, and the like are similarly at risk and need to be protected.

Conventionally, airplane ventilation or other vehicle (e.g., automobile, bus, etc.) and building heating and ventilation systems use high velocity to blow the air into the space and intentionally stir up the air to balance and evenly distribute air temperature. Even a downdraft technology paint booth or lab hood draws and moves air at a high velocity and turbulence. All of these high velocity air forcing distribution methods compromise the air quality of the cabin or room and arguably spread and distribute pathogens, causing more harm than good to occupants.

There is a long-felt need for a cabin or interior space ventilation system, for example for a multi-passenger vehicle such as a bus, that does not agitate the interior air and distribute pathogens, but that still circulates and replaces the air with conditioned air that may be heated, cooled, purified, and/or sterilized as the need may be. “Conditioned air,” as used herein, may be defined as air that has been treated in any of one or more ways such as circulating, heating, cooling, humidifying, dehumidifying, sterilizing, ionizing, filtering, augmenting or replacing with exterior air, or the like.

OVERVIEW

Described herein is a ventilation system for a vehicle having a cabin for transporting passengers. The ventilation system includes a segmented plenum comprising a plurality of sub-plenums that are disposed above the cabin, a perforated panel defining the ceiling of the cabin and having plurality of perforations for air communication of the plenum with the cabin, and ductwork including one or more upper main ducts, one or more lower main ducts, one or more vertical ducts, and one or more seat return ducts. The upper main ducts, lower main ducts, vertical ducts and seat return ducts communicate with each other to convey air, descending from the segmented plenum through the perforated panel as a high volume, low turbulence blanket of air through the cabin, back to the segmented plenum. The ventilation system also includes an air processing unit (APU) in communication with the ductwork and operable to sterilize the air conveyed therein, and one or more fans for circulating the air in the ventilation system.

Also described herein is a vehicle having the ventilation system set forth above.

Also described herein is a method for ventilating a cabin of a vehicle. The method includes balancing air pressure in a plurality of sub-plenums disposed above a cabin and separated therefrom by a perforated panel such that a high volume, low turbulence blanket of air descends through the cabin, capturing and conditioning the descended air before re-introducing it into the sub-plenums.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Example embodiments are described herein in the context of vehicle ventilation systems, and more particularly, multi-passenger vehicle ventilation systems. The following description is illustrative only and is not intended to be in any way limiting. Other embodiments will readily suggest themselves to those of ordinary skill in the art having the benefit of this disclosure. Reference will be made in detail to implementations of the example embodiments as illustrated in the accompanying drawings. The same reference indicators will be used to the extent possible throughout the drawings and the following description to refer to the same or like items.

In the description of example embodiments that follows, references to “one embodiment”, “an embodiment”, “an example embodiment”, “certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. The term “exemplary” when used herein means “serving as an example, instance or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

Described herein is a “High Volume Low Turbulence” (HVLT) system for delivering air through a large plenum (one or more plenums or sub-plenums are contemplated) across substantially the entire top of a vehicle cabin's ceiling through an array of perforations. This approach allows the air, which is evenly pressurized within the plenum(s), to fall planarly, like a sheet across the entire cabin consistently, in blanket fashion.

In certain embodiments, “Air Processing Units” (APUs) are used to supply air. The air may be conditioned as appropriate for passenger comfort and safety, and such conditioning may include any one or more of heating, cooling, humidifying, dehumidifying, sterilizing, ionizing, filtering, augmenting or replacing with exterior air, or the like. The term “conditioning” will thus be used herein to denote any one or more of these actions.

In certain embodiments, two APU's are deployed in the multi-passenger vehicle. Reasons for this include 1) It allows the air plenum(s) to be equally pressurized from both sides, 2) it provides redundancy should one of the system's equipment fail, 3) It provides the most efficient and accurate air cycling of the cabin, and 4) It allows electric heating and air conditioning and other conditioning to be added via a module.

The APU entails a cabinet with a tamper proof access door which is equipped with a battle switch or circuit interrupter switch for safety of maintenance crew due to the dangers of exposure to UVC lighting which may be used for sterilization. The APU operates like a black out box so that there is no possibility of occupants being exposed to the UVC lighting. The APU is sized for the maximum amount of air exposure to the sterilizing UVC bulbs when used, and the bulbs may be designed to special wavelengths of nanometers depending on the targeted pathogens, such as Covid-19. The APU may be designed to expose the air in ratio to the proper UVC lighting in order to implement an effective sterilization regime. The APU can be equipped with both heating and cooling, or any conditioning equipment as that term is defined above.

In certain embodiments, there is a supply duct that comes off each APU and runs up a sidewall of the vehicle cabin and then runs down the side of the of the vehicle, on top of the windows to feed the plenum(s). In certain embodiments, this duct will be plastic so that it is extremely durable and blends with the interior decor of most multi-passenger vehicle cabins. Small in-line booster fans may be deployed within this ductwork to ensure that sub-plenums, when present, remain equally pressurized in a balanced manner.

In certain embodiments, a fully perforated ceiling panel may be implemented, to provide a high volume and low turbulent sheet of air that blankets down across the passengers in a substantially vertical route, carrying particulates down with it and substantially preventing them from dispersing laterally and spreading among passengers. This ceiling panel may have thousands of substantially equally spaced holes (apertures) that allow an even, yet slowly, controlled discharge of air. The plenum depth above the panel ranges from about one to three inches depending on the cabin height for instance.

In certain embodiments, a liquid ceramic heat reflective coating may be applied, as well as a liquid sound reducing coating on the inside bottom of the cabin roof skin.

The pressurized air plenum may be segmented into several “zoned” smaller sub-plenums with the use of small air dampers that allow controllable, even, balanced pressurization. Each sub-plenum may be balanced with manual dampers from the supply duct(s). This blanket of air then falls and is pulled into return air ducts that are located at the perimeter of each seat causing the wind to act like a shear. The air is then returned via a plastic ducting system that is mounted along the floor at both sides of the cabin with branch extensions that feed return ducts under the seats. The seats are equipped with return air ducts at the front, rear, and aisle end. All of this permits the air to be pulled down vertically directly in all areas especially in front of the occupants, which, vastly reduces lateral air motion and eliminates pathogen transfer throughout the air system of the cabin.

In certain embodiments, and for example depending on the geographic location of the vehicle, heat and/or air conditioning may be provided. In certain designs, for example in retrofit configurations of existing passenger vehicles, existing box heaters may be removed as they may cause undesired mixing of air that disrupts the blanket of air approach. In certain embodiments the existing heating element can be installed in an additional module attached to the APU as further detailed below.

In certain embodiments, an air screen or air door is located over the vehicle (e.g. school bus) main access door. This screen/air door can automatically come on (activate) upon the access door being opened. Advantages of such an arrangement are: 1) It prevents the loss of cooled or heated (or otherwise conditioned) air, thus increasing efficiency, 2) It prevents outside contamination from entering the cabin, and 3) It prevents insects from entering the cabin.

It will appreciated that while discussed primarily in terms of a school bus, the system is applicable to any type of multi-passenger vehicle cabin including, but not limited to, public transportation buses, aeronautical aircraft, tour buses, 15-passenger vans or the like, trains, subways, and so on.

FIG.1schematically depicts a multi-passenger vehicle ventilation system100for use in a vehicle, such as a school bus102, in accordance with certain embodiments. Generally, the system100comprises a segmented plenum104from which pressurized conditioned air106(seeFIG.3) is delivered downward into the main passenger cabin through a perforated overhead panel108(seeFIGS.2and3). As seen inFIG.2, perforations109defined in the overhead panel108may be formed in a regular, equidistantly-spaced pattern, although irregular patterns are also contemplated.

Returning toFIG.1, a sequence of partitions110, spaced apart 2-3 feet for example, effect the segmentation of the plenum104into, for example, ten sub-plenums104ithat are substantially sealed from one another and disposed axially in sequence along the length of the bus102. As best seen inFIG.3, in certain embodiments, the panel108may be spaced about 1-3 inches from roof112, generally following the contour of the roof at that spacing along its entire width from the right side114to the left side116of the bus102, with the defined plenum104thereby having a corresponding consistent width of about 1-3 inches. In certain embodiments, one or more coatings (not shown) may be applied to the bottom surface of the roof112, and within the plenum, for example in liquid form for heat and/or sound insulation for instance.

Air supply into the plenum104is provided by way of ductwork comprising a pair of upper main ducts118R (right) and118L (left) (collectively118) that deliver air into each sub-plenum104ithrough dedicated balance valves120i. Each sub-plenum104imay thus be supplied with air by a pair of balance valves120i(FIG.1), one communicating with the upper main duct118R and one communicating with the upper main duct118L. At initial system setup, airflow through each valve120iis adjusted, for example through a valve adjustment mechanism such as a slide door, damper, or the like (not shown), to balance air pressure in the sub-plenums104iso that they are able to evenly deliver, through the perforated overhead panel108, a high volume, low turbulence blanket of air (vertically) downwards into the cabin. Importantly, the inflow of air into the cabin through system100is substantially entirely by way of the plenum104and perforated panel108, without contributions from the side of the vehicle. This results in an even, unagitated down flow of the air in the cabin, avoiding vortices and mixing of the air and its contents. Upper main ducts118R and118L may be made of plastic or other suitable material. Inline booster fans123(FIG.1) may be provided in the ductwork, for example in upper main ducts118R and118L, to aid in movement of air through the ducts and provide air circulation. In certain embodiments the fans123may use brushless fan motors (not shown).

The ductwork of system100also comprises a pair of lower main ducts122R (right) and122L (left) (collectively122) respectively in communication with upper main ducts118R and118L by way of vertical ducts124R and124L (collectively124). Vertical ducts124may be made of plastic and generally run vertically up the back of the vehicle, in the back right and left corners thereof, to connect the respective upper main ducts118and lower main ducts122. In certain embodiments, air circulation in the ductwork is facilitated by the inline booster fans123(FIG.1), which aid in moving the air through the circuit, and sufficiently pressurize the plenum104to motivate the forced downward motion of air through the panel108as described above. The inline booster fans123may be powered by brushless motors (not shown) in some examples.

Lower main ducts122may also be made of plastic or other suitable material and generally extend along the floor of the vehicle cabin, receiving air from a series of seat return ducts126. In certain embodiments, and as best illustrated inFIGS.3and4, two seat return ducts126are associated with each seat127of the vehicle—a front seat return duct126F extending along the width of and beneath the seat at the front thereof, and a back seat return duct126B extending along the width of and beneath the seat at the back thereof. The seat return ducts126have inlets129at the aisle ends thereof (the aisle is defined as the central space between the two rows of seats on either side of the vehicle), as well as at other intermediate locations131along their length and directed at different angles along their perimeter (or circumference in the case of tubular cross-sections). The inlets129are configured to receive cabin air descending vertically from the plenum104, permitting the air to be pulled down vertically directly in substantially all areas especially in front of the occupants, which vastly reduces lateral air motion and eliminates pathogen transfer throughout the air system of the cabin.

With reference toFIG.5, in certain embodiments, system100includes air processing units APU130R and APU130L (collectively130) through which air is circulated, for example for sterilization using ultraviolet light, and/or for heating or cooling as detailed below. Although two APUs130are described, fewer (or more) APUs are also possible in the system100. APUs130include an air inlet132in communication with an inlet pipe134(e.g. 3-inch pipe) at one end, and an air outlet136in communication with an outlet pipe138at another end. Air is provided to the APUs at the air inlet132from the lower main ducts122(FIGS.1and3). The pipes134,138extend substantially interiorly of the APU and communicate with a manifold140that is configured with suitable baffles and the like to permit the air to be sufficiently exposed to UVC light from one or more UVC bulbs139to effectively sterilize it and kill pathogens, such as the Covid-19 virus, during passage of the air through the APU130. The wavelengths of the light may be specifically selected to target particular pathogens, such as Covid-19, and the number of bulbs and intensity is selected for the required exposure given a particular flow rate of air through the APU. Access to the interior of the APU130, for example to permit replacement and servicing of UVC bulbs139, can be facilitated by a providing a removable or openable front or back panels141. One or more such panels can be transparent to permit viewing for maintenance. Suitable circuit precautions, such as a circuit interrupter (not shown), can also be provided for additional safety.

The pipes134,138in APUs130are provided with perforations145through which the air passes into or out of the manifold140, and the perforations can have progressively increasing or decreasing diameters to balance the air pressure so that the air front traversing the manifold140is equally distributed and balanced therein. In certain embodiments, one or more fans143may be provided proximal the outlet136, or at other locations, to help draw the air through the APU130and facilitate circulation in the system100.

With reference toFIG.6, in certain embodiments, one or both APUs130can each include a heat exchanger module142, which can house a heater144and/or a cooler146therein. The heater144can operate by way of a heat exchange element (not shown) such as a hot water coil from the bus heater or powered by a standard 12 V DC (direct current) connection. The cooler146can also be a DC system and operate by way of an evaporator coil (not shown) coupled to an engine mounted air compressor (not shown). A slide-in air filter bank151can be provided in the APU130to help remove particulates and clean the circulating air.

Returning toFIG.1, in certain embodiments, an air door152can be provided, in air communication with the system100, for added security and protection against introduction of pathogens such as Covid-19. The air door152operates to further isolate sterilized cabin air from outside air that may be contaminated.

While embodiments and applications have been shown and described, it would be apparent to those skilled in the art having the benefit of this disclosure that many more modifications than mentioned above are possible without departing from the inventive concepts disclosed herein. The invention, therefore, is not to be restricted based on the foregoing description. This disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative.