Patent Application
20240010047
The present disclosure is directed to techniques for ventilation of an enclosure, such as the cargo space of a vehicle.
Embodiments of the present invention provide techniques for ventilating an enclosure such as the cargo space of a vehicle. In an example implementation, a ventilator is affixed to an external wall (e.g., the roof) of the cargo space. The ventilator includes a ram inlet that flows into a venturi, along one or more openings in a boundary of the cargo space, and exits at an outlet. When the vehicle is in motion, external airflow enters the ram inlet, gets compressed in the venturi, and travels over the top of the one or more openings in the boundary, generating a high shear that pulls airflow from the cargo space, into the diffuser, and out the outlet. The ventilator may include an electric fan that generates suction from the cargo space when the vehicle is stationary, and a moveable flap at the inlet that opens at a threshold vehicle speed and closes below a threshold vehicle speed, directing the suction of the electric fan towards the cargo space.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Illustrative embodiments are described in detail below with reference to the attached drawing figures, wherein:
The cargo space of a commercial vehicle is not typically thermally conditioned (unless required for food or perishable storage). However, hot weather climates can create a high level of solar loading, which results in heat transfer through a metal roof and into the cargo space, potentially superheating the cargo space. For example, if a vehicle is parked in an Arizona parking lot where the ambient temperature is 43° C., after an hour or two, the temperature in the cargo space can increase by almost 30° C. above the ambient temperature to about 73° C. This elevated temperature is too hot for human survival and places an extreme strain on any drivers or operators that must enter the cargo space throughout the day.
To compensate for heat transfer into a cargo space, ventilation techniques seek to exchange hot air in the cargo space with relatively cooler ambient air. However, existing ventilation techniques have a variety of drawbacks. For example, passive ventilators that activate in response to air flow generated when driving (e.g., spinning roof mounted devices that act under wind) typically do not provide enough airflow to be effective against the highest levels of solar loading a vehicle may be exposed to. Active ventilators (e.g., electric fans mounted in a hole in the roof) are used in recreational vehicles (RVs), buses, and commercial vehicles, but typically do not work very well when a vehicle is driving, as driving can make the suction generated by active ventilation less effective. Furthermore, when active ventilators are mounted in a hole in the roof, rain can enter through the hole, which is undesirable. At the extreme end, fully integrated roof-mounted active coolers (e.g., heat-pumps) can be installed for up to >4 kW of cooling power. However, active coolers may not be suitable for various reasons, including the impact of their larger size on vehicle form factor, which can impact shipping or driving clearances, increase drag during operation, reduce energy efficiency, and/or reduce driving range.
Accordingly, embodiments of the present invention are directed to techniques for ventilating an enclosure, such as the cargo space of a vehicle. In an example implementation, a ventilator that is affixed to or otherwise positioned on an external surface of the cargo space generates suction flow out of the cargo space using ram air at higher vehicle speeds and/or using one or more electric fans at lower vehicle speeds. An example ventilator includes a ram inlet that flows into a venturi (or venturi tube), then along one or more openings in a boundary of the cargo space (e.g., a louvered or perforated grille, slats), and finally exits the ventilator at an outlet. When the vehicle is in motion, external airflow (ram air) may enter the ram inlet and get compressed in the venturi, substantially increasing the velocity and reducing the pressure of the airflow. This flow resulting from the Venturi effect travels over the top of the opening(s) in the boundary of the cargo space and generates a high shear, which acts to pull flow through the boundary (e.g., through louvers) from the cargo space and into the main jet, which expands in the diffuser and exits through the outlet. When the vehicle is stationary or at lower speeds, one or more electric fans may be activated or throttled up to provide suction through the boundary of the cargo space. At higher speeds and/or above a threshold speed, the electric fan(s) may be deactivated or throttled down as ram intake becomes more effective at generating the suction.
In some embodiments, the ram inlet includes a moveable flap that blocks the airflow based on vehicle speed, and may be operated passively (e.g., spring loaded shut and opened by ram air), using an electro-mechanical device (e.g., an electromechanical actuator, a stepper motor, active grill shutters) driven by a control signal that corresponds to vehicle speed, and/or otherwise. In some embodiments with a moveable flap, when the vehicle is in motion, the moveable flap may be opened (e.g., gradually as vehicle speed increases), thereby opening the ram airflow path of the ventilator, and the fan(s) of the ventilator may be turned off or throttled down (e.g., gradually as vehicle speed increases). By contrast, when the vehicle is below a threshold speed and/or stationary, the fan(s) of the ventilator may be turned on or throttled up (e.g., gradually as vehicle speed deceases) to compensate for the reduced ram airflow, and the moveable flap may be closed (e.g., gradually as vehicle speed deceases) in order to close the ram inlet and direct the suction of the fan(s) toward the cargo space.
In some embodiments, the boundary between the ventilator and the cargo space may be formed with one or more open areas that permit airflow from the cargo space and one or more solid areas that create a boundary that controls expansion in the diffuser and maintains the Venturi effect. For example, the interface between the ventilator and the cargo space may be formed with a louvered grill, a perforated grille, slats, and/or otherwise. In some embodiments, the interface includes a grille that encourages or guides airflow out of the cargo space (e.g., via perforations with bell mouthed inlets, tapered radii, and/or sharp-edged outlets). In some embodiments, the interface includes an inner grille that encourages airflow out of the cargo space paired with an outer grille (e.g., a louvered grille) such that the openings of the outer grill are aligned with a solid portion of the inner grille, and the inner grille acts as a drip tray that catches falling water that entered into the ventilator and transmits the water to a water drain out of the vehicle.
Various fan arrangements are possible, such as at the boundary of the cargo space or at the outlet of the ventilator. In some implementations with one or more fans at the outlet, the fan(s) are tilted to reduce the vertical height of the ventilator and/or positioned under a grille (e.g., a louvered grille) for water protection.
Generally, any number of ventilators may be placed at any suitable location or locations on an enclosure, such as the roof of a cargo or auxiliary space of a vehicle. For example, a cargo space may be subdivided (e.g., with bulkheads), and multiple ventilators may be used to ventilate multiple subdivisions of the cargo space. In some embodiments, the ram inlet of a ventilator is elevated off the roof or other surface of the enclosure by an amount that avoids the thermal boundary layer of heated air on the surface. Since the thermal boundary layer is typically larger towards the rear of a vehicle, the farther back the ventilator is located on a roof, the higher the ram inlet may be elevated, and vice versa. Although some embodiments described herein contemplate a roof-mounted ventilator, a ventilator may additionally or alternatively be located on any suitable surface or boundary of an enclosure, such as on one or both sides of a vehicle, multiple ventilators on a particular surface, and/or other configurations. Furthermore, although some embodiments described herein contemplate ventilating a cargo space, generally any enclosure may be ventilated using the present techniques, such as some other auxiliary or storage space, an electronics enclosure, or other spaces or volumes. Furthermore, a ventilator may be used to ventilate a space in any suitable vehicle, such as a car, truck, bus, train, boat, or drone, to name a few examples. Moreover, although some embodiments described herein contemplate ventilating a moveable enclosure such as a cargo space of a vehicle, some embodiments use a ventilator to ventilate a stationary enclosure, with wind used for ram air. As such, the structures described herein may be used to apply ventilation that compensates for even the high solar loading that can occur in various environments.
In some embodiments where the enclosure 110 is in a vehicle, the vehicle includes one or more electrical power systems, whether alternating or direct current (AC or DC), at any suitable current and voltage, and one or more power sources such as a battery (e.g., a 12V battery), solar panel, or electric generator, to name a few examples. In an example implementation involving an electric vehicle, the electric vehicle may be fully electric or partially electric (e.g., plug-in hybrid), and may be fully autonomous, partially autonomous, unmanned, human-operated, non-autonomous, or otherwise. An electric vehicle such as an electric truck or automobile may include on-board battery packs, battery modules, or battery cells to power the electric vehicle. A battery, battery pack, battery module, and/or battery cell may be installed or placed within the vehicle (e.g., installed on the chassis of the vehicle within one or more of the front portion 112, the body portion 114, or the rear portion 118), and may include or connect with at least one busbar (e.g., a current collector element) comprising electrically conductive material connecting or otherwise electrically coupling the battery, battery pack, battery module, and/or battery cell with other electrical components of the vehicle to provide electrical power to various systems or components of the vehicle.
In the example illustrated in
In some embodiments, the interface between the expanding portion 315 of the ventilator 300 and the enclosed portion 340 of the enclosure includes one or more grilles, perforated sheets (e.g., with holes), slats, or other structures that form a partially open boundary. Generally, the opening(s) 332 provide ventilation for the enclosed portion 340 of the enclosure, while one or more solid portions (e.g., louvers of a louvered grille 330) create a boundary that controls expansion in the expanding portion 315 and maintains the Venturi effect. In some embodiments, one or more solid portions of the interface (e.g., louvers of a louvered grille 330 angled, for example, at 45°) form one or more turning veins that help direct ventilation airflow into the expanding portion 315 and turn the ventilation airflow towards the outlet 328 (e.g., towards the louvered grille 325), reducing resistance and turbulence. Generally, a variety of openings are possible. As a design principle, the percentage of the area of interface that is open may be selected to balance avoiding choking the ventilation airflow, blocking dirt or debris that may enter into the ventilator 300, and/or maintaining the Venturi effect. In a simple non-limiting example, the opening area may be approximately 50% of the area of the interface.
In some embodiments, the interface includes a grille (e.g., perforated grille 335) that encourages or guides airflow out of the cargo space (e.g., via perforations 338 with bell mouthed inlets, tapered radii, and/or sharp-edged outlets). Additionally or alternatively, the interface includes a slanted inner grille (e.g., perforated grille 335) paired with an outer grille (e.g., louvered grille 330) such that the openings of the outer grill are aligned with a solid portion 339 of the inner grille. As such, and using the embodiment illustrated in
Various design principles may be considered when arranging, sizing, and/or locating various components of the ventilator 300. For example, the amount of compression in the venturi 302 depends on the ratio of the height of the inlet 305 to the height of the throat 310. An example compression ratio may be between 1:1 and 4:1 (e.g., 2:1). Although there would be no compression (and no venturi) with a ratio of 1:1, ram airflow through such a channel would still generate shear along the interface with the enclosed portion 340 of the enclosure. Compression ratios above 4:1 are possible, but may be less effective since less air may be captured.
In some embodiments, the enclosure includes a hole (e.g., in the roof) that accommodates the ventilator 300 (e.g., the louvered grille 330 and/or the perforated grille 335), and the size of the hole may be chosen to control how rapidly expansion occurs in the venuri, to make room for a fan (e.g., an interface-mounted fan), to provide separation between the inlet 305 and the outlet 328 (e.g., the louvered grille 325) to limit water ingestion, and/or other considerations. In a nonlimiting example technique, starting with the cross-section view as illustrated in
In some embodiments, the inlet 305 is spaced away from the surface 360 of the enclosure to avoid taking in air from the thermal boundary layer 355 on or adjacent to the surface 360. For example and returning to
In
In some embodiments, the electric fan 320 may be controlled using a control signal that represents speed of the enclosure. For example, the electric fan 320 may be may be activated or throttled up at lower speeds (e.g., below 10 to 15 mph), and/or may be deactivated or throttled down at higher speeds (above 10 to 15 mph). Speed may be measured or otherwise determined using any suitable technique (e.g., using a vehicle or transmission speed sensor, using an airspeed indicator or gauge, determining changes in radiolocated position over time, etc.), and an electronic representation of the speed may be used to generate a control signal that drives the electric fan 320. For example, a vehicle speed sensor may output a speed signal, and the speed signal may be scaled, offset, gain controlled, regulated, and/or otherwise mapped on a desired voltage range, and the resulting control signal may be applied to the electric fan 320. In some embodiments, the electric fan 320 may be activated below a threshold speed (e.g., 10 mph), throttled gradually over a range of speeds (e.g., 10-15 mph), and/or deactivated above a threshold speed (e.g., 15 mph).
The moveable flap 470 may comprise a hinged or otherwise actuated door that blocks the inlet 405 based on speed of the enclosure. In some embodiments, the moveable flap 470 is controlled passively. For example, the moveable flap 470 may be spring loaded shut with a spring selected to balance the force applied on the moveable flap 470 by ram airflow up to a desired threshold speed (e.g., 10 to 15 mph). As such, the moveable flap 470 may remain spring loaded shut when the enclosure is moving at lower speeds, and may gradually open and allow ram airflow to enter the ventilator 400 at higher speeds.
In some embodiments, the moveable flap 470 is controlled using some electro-mechanical device (e.g., an electromechanical actuator, a stepper motor, active grill shutters) driven by a control signal that corresponds to speed of the enclosure. For example, and as described in more detail above, speed may be measured or otherwise determined using any suitable technique and an electronic representation of the speed may be used to generate a control signal that drives the electro-mechanical device and actuates the moveable flap 470. For example, a vehicle speed sensor may output a speed signal, the speed signal may be scaled, offset, gain controlled, regulated, and/or otherwise mapped on a desired voltage range, and the resulting control signal may be applied to the electro-mechanical device to open and shut the door at a desired speed (or over a desired range of speeds). In some embodiments, the moveable flap 470 may be shut below a threshold speed (e.g., 10 mph), gradually opened over a range of speeds (e.g., 10-15 mph), and/or open above a threshold speed (e.g., 15 mph).
In some embodiments that include both an electric fan (e.g., the electric fan 420) and a moveable flap (e.g., the moveable flap 470), the electric fan and the moveable flap may both be controlled using vehicle speed. For example, when the enclosure is in motion, the moveable flap 470 may be opened (e.g., gradually as speed increases), thereby opening the ram airflow path of the ventilator 400, and the electric fan 420 may be turned off or throttled down (e.g., gradually as speed increases). By contrast, when the enclosure is below a threshold speed and/or stationary, the electric fan 420 may be turned on or throttled up (e.g., gradually as speed deceases) to compensate for the reduced ram airflow, and the moveable flap 470 may be closed (e.g., gradually as speed deceases) in order to block the inlet 405 and direct the suction of the electric fan 420 toward the enclosed portion 440 of the enclosure.
While operations are depicted in the drawings in a particular order, such operations are not required to be performed in the particular order shown or in sequential order, and all illustrated operations are not required to be performed. Actions described herein can be performed in a different order.
Having now described some illustrative implementations, it is apparent that the foregoing is illustrative and not limiting, having been presented by way of example. In particular, although many of the examples presented herein involve specific combinations of method acts or system elements, those acts and those elements may be combined in other ways to accomplish the same objectives. Acts, elements and features discussed in connection with one implementation are not intended to be excluded from a similar role in other implementations or implementations.
The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” “comprising” “having” “containing” “involving” “characterized by” “characterized in that” and variations thereof herein, is meant to encompass the items listed thereafter, equivalents thereof, and additional items, as well as alternate implementations consisting of the items listed thereafter exclusively. In one implementation, the systems and methods described herein consist of one, each combination of more than one, or all of the described elements, acts, or components.
Any references to implementations or elements or acts of the systems and methods herein referred to in the singular may also embrace implementations including a plurality of these elements, and any references in plural to any implementation or element or act herein may also embrace implementations including only a single element. References in the singular or plural form are not intended to limit the presently disclosed systems or methods, their components, acts, or elements to single or plural configurations. References to any act or element being based on any information, act or element may include implementations where the act or element is based at least in part on any information, act, or element.
Any implementation disclosed herein may be combined with any other implementation or embodiment, and references to “an implementation,” “some implementations,” “one implementation” or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with the implementation may be included in at least one implementation or embodiment. Such terms as used herein are not necessarily all referring to the same implementation. Any implementation may be combined with any other implementation, inclusively or exclusively, in any manner consistent with the aspects and implementations disclosed herein.
References to “or” may be construed as inclusive so that any terms described using “or” may indicate any of a single, more than one, and all of the described terms. References to at least one of a conjunctive list of terms may be construed as an inclusive OR to indicate any of a single, more than one, and all of the described terms. For example, a reference to “at least one of ‘A’ and ‘B’” can include only ‘A’, only ‘B’, as well as both ‘A’ and ‘B’. Such references used in conjunction with “comprising” or other open terminology can include additional items.
Where technical features in the drawings, detailed description or any claim are followed by reference signs, the reference signs have been included to increase the intelligibility of the drawings, detailed description, and claims. Accordingly, neither the reference signs nor their absence have any limiting effect on the scope of any claim elements.
Modifications of described elements and acts such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations can occur without materially departing from the teachings and advantages of the subject matter disclosed herein. For example, elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of discrete elements or positions can be altered or varied. Other substitutions, modifications, changes and omissions can also be made in the design, operating conditions and arrangement of the disclosed elements and operations without departing from the scope of the present disclosure. For example, the fluid lines or fittings described can be configured for use in various other components including, but not limited to, plumbing systems or other piping systems. Further relative parallel, perpendicular, vertical or other positioning or orientation descriptions include variations within +/−10% or +/−10 degrees of pure vertical, parallel or perpendicular positioning. References to “approximately,” “substantially” or other terms of degree include variations of +/−10% from the given measurement, unit, or range unless explicitly indicated otherwise. Coupled elements can be electrically, mechanically, or physically coupled with one another directly or with intervening elements. Scope of the systems and methods described herein is thus indicated by the appended claims, rather than the foregoing description, and changes that come within the meaning and range of equivalency of the claims are embraced therein.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.
