Patent Application
20140265435
Motor vehicles, and in particular trucks, are a critical component of the system for transporting materials, goods and people from place to place. The amount of energy required to move such vehicles depends on many factors. For instance, a substantial amount of energy is expended to overcome the resistance encountered in moving the vehicle through air. The amount of energy expended depends in large part on the aerodynamic drag force exerted on the vehicle by the air. A vehicle moving through air experiences a drag force, which may be divided into two components: frictional drag and pressure drag. Frictional drag comes from friction generated generally through the boundary layer as the vehicle passes through the air. Pressure drag results from the net pressure forces exerted as the air flows around the vehicle. A substantial component of the pressure drag is associated with the formation of a low pressure zone behind the vehicle, as evidenced by the formation of a wake behind the vehicle.
The distinction between frictional drag and pressure drag is useful because the two types of drag are due to different flow phenomena. Frictional drag is typically most important for attached flows—that is, where the flow boundary layer has not separated from the vehicle surfaces, and is related to the surface area exposed to the flow. Pressure drag dominates for separated flows, and is generally related to the cross-sectional area of the vehicle facing the air flow. When the drag on vehicle is dominated by pressure drag forces, it will expend far more energy traveling through air than the same vehicle dominated by friction drag forces. It is therefore advantageous in the design of a vehicle to reduce pressure drag forces; thereby increasing the aerodynamic properties and efficiency of the vehicle.
A bluff body, such as a conventional truck hood or front section, produces significant pressure drag at typical highway speeds. One reason for the large pressure drag is the presence of a sharp angle located at a leading edge of the truck hood. More specifically, typical truck front sections include a substantially vertical front surface or grill that meets, along an upper edge, a substantially horizontal top surface. The air flow passing over the front section, therefore, must negotiate an abrupt change in direction as the edge where the hood structure transitions from a substantially vertical orientation to a substantially horizontal orientation. This abrupt turn causes the flow to ‘separate’ from the top surface of the hood, forming a highly turbulent region of air located directly above the top surface of the hood, between the leading edge and the windshield.
Another reason for large pressure drag on a bluff body, such as a conventional truck front section, is the presence of a sharp angle located at a lower edge of the truck bumper and the passage of airflow underneath the vehicle and associated trailer. At highway speeds, such underbody air flow interacts with undercarriage components, such as wheel assemblies, skid plates, oil pans, transmission housings, drive shafts, chassis structure, etc., which in turn, develops a substantial amount of turbulent airflow in the underbody region of the vehicle and/or trailer.
To address such aerodynamic deficiencies caused by underbody air flow, air dams have been created to block the air flow. One example of a conventional air dam is shown in
Thus, there exists a need, among others, for an aerodynamically designed front bumper section of a motor vehicle that mitigates drag forces imparted by underbody air flow.
A first exemplary embodiment of a disclosed air dam is configured to improve the aerodynamic characteristics of a vehicle. The air dam includes a vertically extending component that extends downward from an area below a front bumper of the vehicle. The air dam further includes a horizontally extending component that extends forward from an upper end of the vertically extending component to an area located forward of a leading edge of the bumper.
A second exemplary embodiment of an air dam includes a vertically extending component that extends downward from an area below a front bumper of the vehicle. The air dam further includes a horizontally extending component that extends forward from an upper end of the vertically extending component to an area located forward of a leading edge of the bumper. A second horizontally extending component extends in a rearward direction from a lower end of the vertically extending component.
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 of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The detailed description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed.
The following discussion provides examples of systems and methods for improving the aerodynamic efficiency (e.g., reduce drag) on vehicles. Several embodiments of the present disclosure are directed to systems and methods that utilize one or more fairings, deflectors, vanes, fins, etc., on the front section of a vehicle for reducing the aerodynamic drag thereon. Non-limiting examples of vehicles that may benefit from the aerodynamic devices and methods of the present disclosure include but are not limited to light, medium, and heavy duty trucks, recreational and vocational vehicles, buses, etc., just to name a few. Although embodiments of the present disclosure will be described with reference to a Class 8 truck, one skilled in the relevant art will appreciate that the disclosed embodiments are illustrative in nature, and therefore, should not be construed as limited to applications with Class 8 trucks. It should therefore be apparent that the aerodynamic components and drag reducing methods of the present disclosure have wide application, and may be used in any situation where reducing the drag of any type of a vehicle is desirable.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.
One suitable vehicle in which the aerodynamic component of the present disclosure may be employed will now be described in more detail with reference to
As best shown in
The hood 40 extends rearwardly from an upper leading edge 42 of the grille crown 36 to the windshield 48 of a cab section. The front section 28 further includes fenders 56 that cover the wheels 22 and a bumper 64 that extends horizontally across the front of the vehicle 20 just beneath the vehicle grille 32 and fenders 56. In the embodiment shown, the bumper 64 includes a centralized opening 68 that permits air therethrough.
Referring now to
As best shown in
The airflow A also impinges on the contact surface 134 of the vertically extending component 126 of the air dam 120, and is directed laterally outwardly with respect to the longitudinal axis of the vehicle, which in turn, aims to reduce drag on the vehicle from such components as the wheels 22 and other components associated with the undercarriage of the vehicle. In addition, the configuration and arrangement of the horizontally extending component 130 forces air through the centralized opening 68 of the bumper 64, which in turn, provides improved air flow through an associated cooling module positioned behind the bumper, in the engine compartment, etc.
It should be noted that for purposes of this disclosure, terminology such as “upper,” “lower,” “vertical,” “horizontal,” “fore,” “aft,” “inner,” “outer,” “front,” “rear,” etc., should be construed as descriptive and not limiting the scope of the claimed subject matter. Further, the use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings.
The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure, as claimed.
This application claims the benefit of U.S. Provisional Application No. 61/777,478, filed Mar. 12, 2013, the disclosure of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61777478 | Mar 2013 | US |
