The present application relates generally to vehicle air ducts, and more specifically to devices for actively regulating air flow to areas in a vehicle wheel well.
The present disclosure is directed to air duct systems for a vehicle, which can include active air scoops. An air duct system for a vehicle can include one or more ducts capable of directing air to a wheel well of a vehicle, and an active air scoop positioned at an inlet of the duct. The air scoop can be configured to control the amount of air flow to the inlet. In some configurations, the air duct can include one or more outlets to the wheel well, including outlets to a low-pressure area of a wheel well and brake components of the vehicle.
In some cases, the air duct system can include two or more active air scoops. In some examples, each air scoop can independently control air flow to a respective air duct. In other cases, a single active air scoop can control air flow to two or more branches of a duct (e.g., based on how open the air scoop is). In some cases, the air scoop can sit flush against the underbody of the vehicle when in a closed position. The air duct system can also include one or more valves within an air duct configured to direct the air flow to one or more branches within the duct.
In some examples, the operation of one or more active air scoops can be controlled based on the determined temperature in the respective wheel well associated with an active air scoop. For example, an air scoop can be configured to stay open only long enough to cool brake components of a vehicle, but then close when not needed in order to improve aerodynamic efficiency.
It should be noted that the drawing figures may be in simplified form and might not be to scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directional terms, such as top, bottom, left, right, up, down, over, above, below, beneath, rear, front, distal, and proximal are used with respect to the accompanying drawings. Such directional terms should not be construed to limit the scope of the disclosure in any manner.
When a vehicle is in motion, a complex 3-dimensional system of air flow patterns is generated around the vehicle. The flow patterns can be generally grouped as flow past the front of the vehicle, flow over the sides and roof, flow in the gap between a bottom surface of the vehicle and the road, and flow behind the vehicle (wake). These air flow patterns can result in areas or zones of vastly different pressure surrounding the vehicle. Depending on the aerodynamics of the vehicle design, high pressure areas can resist forward movement of the vehicle, and low pressure areas can result in drag that results in forces acting in the direction of the air flow (opposite from the vehicle motion). Both of these resultant forces can either impede the performance of the vehicle, or in the design stage result in the choice of a larger engine to achieve desired performance. In a gasoline or diesel powered vehicle, the resultant forces can decrease the fuel mileage of the vehicle. In an electric vehicle, the resultant forces can decrease the range of the vehicle.
At the front of the moving vehicle, when there can be insufficient air flow to direct the air immediately in front of the vehicle around, over or under the vehicle, the velocity of the air can approach zero. At this point, the static pressure can reach a maximum value, referred to as the stagnation pressure. The area where stagnation pressure occurs is referred to as the stagnation region (see, for example,
Additionally, in modern automotive design, wheel wells now house many thermal sinks that are placed there to bleed off excess energy in the form of heat. A non-exhaustive list of such thermal sinks includes: vehicle brakes, oil coolers, radiators, air conditioning heat exchangers, and battery coolant plates. The placement of these thermal sink components in a wheel well that experiences limited air flow can result in the formation of thermal micro climates surrounding individual thermal sinks. These micro climates may act to limit the designed efficiency of those thermal sinks and negatively affect the associated vehicle system.
Referring now to
As illustrated by the arrows in
The duct inlet 415 can comprise any shape conducive to non-turbulent flow of the air through the duct 405. As such, the duct inlet 415 can be round, oval, rectangular, and the like. The duct inlet 415 can be front facing, or it can be submerged (such as a NACA duct). Although not illustrated in
Depending on the structural design of the vehicle 100, routing the first and second ducts 405, 605 through the structure of the vehicle 100 to the wheel well 425 can prove challenging. Therefore,
In various embodiments, the duct 405 can further comprise a valve 715 to regulate the air flow through the duct 405. The valve 715 can be moveable from a first position in which a maximum air flow is allowed through the duct, to a second position (shown in broken lines) in which the duct 405 is closed or nearly closed, or any position in between. Movement and positioning of the valve 715 can be controlled and directed by a system controller, which in turn can be in communication with an intelligent agent. The intelligent agent can be located within the vehicle 100 or external to the vehicle 100. In various embodiments, the system control can determine a position of the valve 715 based on input data from one or more sensors (not shown). Exemplary sensors can comprise, but are not limited to, pressure sensors located at any exterior point on the vehicle 100 or within the first or second duct 405, 605 or wheel well 425, temperature sensors in the brakes 410, ambient temperature sensors, speed sensors, throttle position sensors, and the like.
In various embodiments, the valve 715 can be positioned where the first and second branches 705, 710 extend from the duct 405 as illustrated in
The valve 715 can be a butterfly valve, a flapper valve, a ball valve, a disk valve, a shutter valve, a gate valve, a globe valve, or any other device known in the art to regulate fluid flow. The valve 715 can, for example, be electrically operated, or hydraulically operated.
In other examples, rather than directing airflow from front of air dam as described above with reference to
The active cooling air scoop may be formed from the same material as the underbody of the vehicle. In some embodiments, it may be a pliable or flexible material which can be made of suitable materials to withstand weather and temperature extremes. Such materials include natural and synthetic polymers, various metals and metal alloys, naturally occurring materials, textile fibers, and all reasonable combinations thereof.
In further contemplated embodiments of the present disclosure, shape-changing or shape-shifting material can also be used in any of the embodiments. The shape-changing aspect of the disclosure is enabled by hardware comprised of motors and actuators governed by a vehicle dynamic control algorithm in a controller. Shape-changing or smart materials are materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields.
The active air scoops 101 are depicted with a fixed outer shape consisting of a flat planar bottom, a straight forward edge, and side walls forming a scoop or channel for air. In a separate contemplated embodiment, each active air scoop 101 has side walls that accordion down such that they form a continuous side wall from the bottom of the scoop to the vehicle underbody. That is, these airflow guiding pieces, each of which has a specific shape, and the pieces may retain their shape whether the pieces are deployed or retracted. In a further contemplated embodiment, any of these guiding pieces can be replaced or augmented by using pliable materials and underlying frames movable by actuators 302 which are governed by a controller 321. For instance, instead of using an underbody panel 104 made of rigid material, the underbody panel 104 is made of an underlying framework enveloped in the pliable material. By actively controlling the movement and shapes of the underlying frame, one can effectively change the outer contour of this particular underbody panel 104. The controller can also selectively change the location of the throat section by shifting the contraction fore or aft to modify aerodynamic distribution of front-to-rear wheel 210, 205 loading.
The active air scoop 101 can be moved using an actuator 302. The actuator 302 can, for example, be electrically operated, or hydraulically operated. In some embodiments, a rod or cable that is connected to an actuator 302, and used to move the active air scoop 101. Each actuator 302 may be configured to open the air scoop through a range of different angles. This opening angle may be selectively chosen to optimally balance the amount of cooling air allowed in while balancing the drag created by opening the active air scoop 101. At different times, each active air scoop 101 may be opened as required by the local thermal environment of the wheel well that active air scoop 101 is associated with.
In one contemplated embodiment, during a hard-turning brake event, the wheel wells 103 on the side facing away from the turn may be cooler and thus require less cooling. The active air scoops 101 on that side of the vehicle may be deployed at a shallow angle relative to the underbody of the car. Conversely the wheel wells 103 on the side of the vehicle closest to the turn may experience greater heat from heavier braking and require significant cooling. The active air scoops 101 may be deployed to a greater angle relative to the underbody of the car on that side. In an emergency braking scenario, high levels of heat may be generated or expected to be generated at all wheel wells 103. The active air scoops 101 in this situation may be deployed to their fullest deployable angle.
Further, movement and positioning of the active air scoop 101 can be controlled and directed by a system controller, which in turn can be in communication with an intelligent agent. The intelligent agent can be located within the vehicle 100 or external to the vehicle 100. In various embodiments, the system control can determine a position of the active air scoop 101 based on input data from one or more sensors (not shown). Exemplary sensors can comprise, but are not limited to, pressure sensors located at any location in the wheel well 103 on the vehicle underbody 104 or within the duct 405 on any thermal emitting component within the wheel well 103. These include thermal sensors on the vehicle brakes oil coolers, radiators, and the like.
Each active air scoop 101 is connected to its respective wheel well 103 via a duct 405. The duct inlet 415 can comprise any shape conducive to non-turbulent flow of the air through the duct 405. This duct inlet is communicatively coupled to the active air scoop 101 and the duct inlet 415 begins at the hinged side of the active air scoop 101. As such, the duct inlet 415 can be round, oval, rectangular, and the like. The duct inlet 415 is communicatively attached to the active air scoop 101. Although not illustrated in
In some embodiments, duct 405 can extend further into the wheel well 103 such that the duct outlet 420 is positioned in closer proximity to the region of low pressure 220. In other embodiments, one or more ducts can be utilized to provide air to both brake rotors and region of low pressure 220.
As with the embodiments described above, movement and positioning of the air scoop (and in some embodiments, valve 715) can be controlled and directed by a system controller, which in turn can be in communication with an intelligent agent. The intelligent agent can be located within the vehicle 100 or external to the vehicle 100. In various embodiments, the system control can determine a position of the valve 715 based on input data from one or more sensors (not shown). Exemplary sensors can comprise, but are not limited to, pressure sensors located at any exterior point on the vehicle 100 or within the first or second duct 405, 605 or wheel well 425, temperature sensors in the brakes 410, ambient temperature sensors, speed sensors, throttle position sensors, and the like.
One or more temperature sensors may be implemented in some embodiments of this disclosure. A thermocouple may be placed in direct contact with some part of the brake system located in a wheel well. In one embodiment, this sensor is a thermocouple that is placed on a surface that is not in the direct path of any cooling air that may be introduced when the active air scoop 101 is deployed. By keeping the thermocouple out of the direct path of cooling air a more accurate thermal reading may be made. In other embodiments, a number of thermocouples are placed both on various vehicle brake components and on other thermal sources in the wheel well.
In another contemplated embodiment one or more IR sensors may be used to detect the temperature of individual components in the wheel well. An IR sensor may be placed in direct line of site with the brake rotor, brake caliper, brake line, or another brake part. The use of multiple IR detectors or a single IR detector that is mechanically targeted at multiple thermal points is also contemplated.
Additionally, brake system temperature may be modeled on existing vehicle inputs such as vehicle speed, brake pressure, brake force applied over a given time, and other similar vehicle data points. Known brake algorithms may be used to calculate the change in kinetic energy of the vehicle. The change in the kinetic energy of the vehicle over a given time may be used to calculate the amount of kinetic energy absorbed by the vehicle's brakes. Known algorithms may be used to estimate the temperature of a vehicle's brake system after it has absorbed a calculated amount of kinetic energy. As such, a vehicle's brake temperature may be estimated without directly measuring the temperature of a vehicles brake system.
In some embodiments, the active air scoops are managed independently. Thus, when the thermal components located in a wheel well do not need additional cooling, the active air scoop is not deployed. However, if cooling is needed by one more thermal components in a wheel well, then the active air scoop is deployed.
It will be understood that the active air scoops may be opened fully or to a partial opened state depending on the commands from the brake management system. In one embodiment, the brake management system receives a thermal signal indicating the wheel well 103 temperature is above a thermal limit. The brake management system commands an actuator to open the active air scoop 101 associated with that wheel well to a half way open position. The brake management system then waits a prescribed period of time, which in some cases may be between 5 and 60 seconds. If the temperature in that wheel well is still above a thermal limit after the prescribed period has passed, then the brake management system may command an actuator to open the active air scoop to a fully open position. If the temperature in that wheel well falls below the thermal limit at any point, then the brake management system may command an actuator to close the active air scoop.
It will be understood by those skilled in the art that the brake management system described herein may be the vehicle's primary braking system or it may be a subsystem within a vehicle braking system. In other contemplated embodiments, the brake management system described herein as the control system for the active air scoops may be a separate system from the rest of the vehicle's braking system.
While the present disclosure has been described in connection with a series of preferred embodiments, these descriptions are not intended to limit the scope of the disclosure to the particular forms set forth herein. The above description is illustrative and not restrictive. Many variations of the embodiments will become apparent to those of skill in the art upon review of this disclosure. The scope of this disclosure should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.
As used herein, the term “vehicle” refers to any land vehicle, motorized, electric, and hybrid. It also includes all vehicle types, including sedans, sports cars, station wagons, sports utility vehicles, trucks, vans, and tractor trailers.
As used herein, the terms “retracted” and/or “retractable” in conjunction with the ability for an airflow guiding piece to move, refer to a motion of retrieving the guiding piece back toward the vehicle's underbody, as opposed to moving away from the vehicle and toward the ground. It should be noted that these terms do not define how the guiding pieces are retrieved, and they do not define in what direction the guiding pieces are retrieved. For example, to “retract” an active air scoop, the motion can include pivoting the active air scoop in almost a rotating action along a longitudinal side of the side skirt. Likewise, to “retract” a side skirt can also include the motion of lifting the side skirt in a vertical direction toward the underbody without rotating the side skirt along its longitudinal side.
As used herein, the terms “having”, “containing”, “including”, “comprising”, and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
Filing Document | Filing Date | Country | Kind |
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PCT/US2017/020267 | 3/1/2017 | WO | 00 |
Number | Date | Country | |
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62301955 | Mar 2016 | US | |
62353950 | Jun 2016 | US |