Claims:1. A hood assembly (100) for reducing aerodynamic drag on a vehicle (101), the hood assembly (100) comprising:
a hood (103) adapted to rotate about a fixed point at a first end (102A) of an engine compartment (102) in the vehicle (101), when a measured speed of the vehicle (101) exceeds at least one of a plurality of pre-set speed values;
one or more under-hood members (105) coupled to the hood (103) at a second end (102B) of the engine compartment (102), wherein the second end (102B) is closer to a windshield (101A) of the vehicle (101) than the first end (102A), and wherein the one or more under-hood members (105) are adapted to move to at least a first position towards the windshield (101A) upon rotation of the hood (103); and
one or more actuators (104) coupled to one or more of the hood (103) and the one or more under-hood members (105) and configured to rotate the hood (103), deploy the one or more under-hood members (105) towards at least the first position, or a combination thereof, based on the measured speed of the vehicle (101).

2. The hood assembly (100) as claimed in claim 1, wherein the one or more actuators (104) are interfaced with an on-board control unit (108) in the vehicle (101), and the on-board control unit (108) and are configured to receive one or more of the measured speed of the vehicle (101), a desired angle of rotation of the hood (103), and a desired position of each of the under-hood members (105) between corresponding default positions and the windshield (101A) based on one or more stored mappings between the measured speed, the desired angle of rotation of the hood (103), and the desired position of each of the under-hood members (105) that are predetermined to achieve a desired value of one or more aerodynamic performance parameters corresponding to the vehicle (101).

3. The hood assembly (100) as claimed in claim 2, wherein the one or more actuators (104) are configured to rotate a trailing edge (103B) of the hood (103) upwards and away from a resting position of the trailing edge (103B) at the second end (102B) of the engine compartment (102), deploy the one or more under-hood members (105) towards at least the first position, or a combination thereof, based on the measured speed and the stored mappings.

4. The hood assembly (100) as claimed in claim 2, wherein the on-board control unit (108) is further configured to:
measure the value of the aerodynamic performance parameters corresponding to the vehicle (101) subsequent to one or more of the rotation of the hood (103) and deployment of the one or more under-hood members (105) as feedback; and
configure the one or more actuators (104) to further adjust a position of one or more of the hood (103) and the one or more under-hood members (105) based on the feedback to achieve the desired value of one or more aerodynamic performance parameters corresponding to the vehicle (101).

5. The hood assembly (100) as claimed in claim 2, wherein the one or more under-hood members (105) comprise at least a first under-hood member (105A) and a second under-hood member (105B), and wherein the first under-hood member (105A) is stacked over the second under-hood member (105B) ) based on the measured speed and the stored mappings.

6. The hood assembly (100) as claimed in claim 2, wherein the one or more under-hood members (105) comprise a single under-hood member (105) that further comprises a plurality of segments, and wherein the one or more actuators (104) are configured to selectively position each of the plurality of segments at one or more positions between corresponding default positions under the hood (103) and the windshield (101A) based on the measured speed and the stored mappings.

7. The hood assembly as claimed in claim 1, wherein the one or more actuators (104) are configured to hold the hood (103) in a rotated position, support the one or more under-hood members (105) coupled to an underside of the hood (103), or a combination thereof.

8. The hood assembly (100) as claimed in claim 1, wherein the one or more actuators (104) are configured to rotate the hood (103) back and retract the one or more under-hood members (105) to corresponding default positions when the measured speed of the vehicle (101) falls below one or more of the pre-set speed values.

9. The hood assembly (100) as claimed in claim 1, wherein the one or more actuators (104) are configured to rotate the hood (103) back and retract the one or more under-hood members (105) to corresponding default positions when one or more wipers of the vehicle (101) are actuated.

10. The hood assembly (100) as claimed in claim 1, wherein the one or more under-hood members (105) are coupled to an underside of a trailing edge (103B) of the hood (103), wherein the one or more under-hood members (105) are coupled to a surface above the hood (103) at the trailing edge (103B) of the hood (103), or a combination thereof.

11. The hood assembly (100) as claimed in claim 1, wherein hood (103) is adapted to rotate up to a predetermined angle, wherein the predetermined angle is selected to prevent obstruction of visibility of a driver of the vehicle (101).

12. A vehicle (101) comprising the hood assembly as claimed in claim 1.

13. A method for reducing aerodynamic drag on a vehicle (101), the method comprising:
measuring a speed of the vehicle (101);
comparing the measured speed with a plurality of pre-set speed values; and
operating one or more actuators (104) coupled to one or more of a hood (103) and one or more under-hood members (105) in the vehicle (101) when a measured speed of the vehicle (101) exceeds at least one of a plurality of pre-set speed values, wherein the one or more actuators (104) are configured to rotate the hood (103) and deploy the one or more under-hood members (105) to at least a first position towards a windshield (101A) of the vehicle (101), or a combination thereof, when the measured speed of the vehicle (101) exceeds at least one of the plurality of pre-set speed values.

14. The method as claimed in claim 13, further comprising configuring the one or more actuators (104) to rotate the hood (103) and deploy the one or more under-hood members (105) to at least the first position towards the windshield (101A) based on one or more mappings stored in an on-board control unit (108) in the vehicle (101).

15. The method as claimed in claims 14, wherein the measured speed of the vehicle (101) and the one or more stored mappings define a desired angle of rotation of the hood (103) and a desired position of each of the under-hood members (105) between corresponding default positions and the windshield (101A) at different speeds of the vehicle (101) for achieving a desired value of one or more aerodynamic performance parameters corresponding to the vehicle (101).

16. The method as claimed in claim 14, the one or more aerodynamic performance parameters comprise one or more of an aerodynamic drag coefficient, a downforce, and a lift force.

17. The method as claimed in claim 14, wherein the on-board control unit (108) is configured to:
measure value of one or more of the aerodynamic performance parameters corresponding to the vehicle (101) subsequent to one or more of the rotation of the hood (103) and deployment of the under-hood members (105) as feedback; and
configure the one or more actuators (104) to further adjust a position of one or more of the hood (103) and the under-hood members (105) based on the feedback to achieve the desired value of one or more of the aerodynamic performance parameters corresponding to the vehicle (101).

18. The method as claimed in claim 13, further comprising configuring the one or more actuators (104) to rotate the hood (103) back and retract the one or more under-hood members (105) to corresponding default positions when the measured speed of the vehicle (101) falls below one or more of the pre-set speed values.

19. The method as claimed in claim 13, further comprising configuring the one or more actuators (104) to rotate the hood (103) and deploy the one or more under-hood members (105) so as to modify a shape of the vehicle (101) to match an airfoil shape to improve aesthetics of the vehicle (101).
, Description:The following specification particularly describes the invention and the manner in which it is to be performed.

HOOD ASSEMBLY FOR REDUCING AERODYNAMIC DRAG ON A VEHICLE AND A METHOD THEREOF

TECHNICAL FIELD

[0001] The present disclosure generally relates to the field of automobile engineering. Particularly, but not exclusively, the present disclosure relates to a system and method for improving aerodynamics of vehicles. Further, embodiments of the present disclosure disclose a hood assembly for reducing aerodynamic drag on the vehicle.

BACKGROUND

[0002] It is generally known that a vehicle moving in air experiences two types of aerodynamic forces, viz. drag force in a direction opposite to a direction of travel, and lift force acting perpendicular to the drag force which tends to lift the vehicle in vertical direction. The drag force, alternatively referred to as air resistance, can be classified into two major categories, namely frictional drag and pressure drag. Frictional drag comes from friction that depends on a cross-sectional surface area and velocity of the vehicle body acting against air as the vehicle passes through it. Pressure drag results from the net pressure forces exerted as the air flows around the vehicle.
[0003] With an increase in both of these drag forces, the vehicle will have to expend substantial amount of energy to overcome them and to propel the vehicle forward. The increased energy expenditure results in significant increase in fuel consumption by the vehicle, which adversely affects fuel economy of the vehicle. Hence, there is a need to alter or modify design characteristics of the vehicle to improve aerodynamics around the vehicle, so that, the vehicle exhibits enhanced mobility without compromising with fuel economy while traveling at increased speeds. It should also be noted that even a minor modification in aerodynamic design of vehicle can result in considerable improvements in fuel economy and mobility of the vehicle. Hence, the art of aerodynamic design is continuously evolving, or rather improving day by day with advancement in related science and technology areas.
[0004] Conventionally, vehicle manufacturing industries, such as but not limited to automotive industries, which manufacture cars are always looking ways to reduce aerodynamic drag force by reducing drag co-efficient (denoted by Cd). Drag co-efficient is an aerodynamic indicator for drag force which is mathematically equivalent to twice the drag force divided by the product of density of air, effective area of cross-section exposed to air, and square of velocity with which the vehicle is travelling relative to air.
[0005] One technique which is extensively employed to reduce the drag co-efficient is to alter or modify aerodynamic design of the exterior of the vehicle body. The vehicle exterior design is modified in such a way that the end shape resembles an aerofoil shape or a near aerofoil shape which is known to have optimal aerodynamic characteristics with respect to frictional and pressure drag. In addition to this, certain add-ons or fitments including, but not limited to, spoilers, bonnet flaps, deployment fins attached to the grills, and so on are provided at specified locations on exterior of the vehicle to allow better control over the mobility of the car.
[0006] Though presence of spoilers and grills on vehicle bodies optimize aerodynamic performance of the vehicles at low and moderate speeds, they complicate the engineering design and often exhibit reliability issues, thereby impeding vehicle performance at high speeds. This also impairs driving comfort and drivability of the vehicle on rough road surfaces. Moreover, adjustable streamlining surfaces belonging to such add-ons may pose numerous drawbacks such as reduced aesthetics of exterior of the vehicle, and requirement of a mechanically strong, heavy, and high-cost, support and actuating system to withstand aerodynamic stress. Another method of reducing effects of drag force on a vehicle is to modify the vehicle’s windshield wiper design. The effect that windshield wipers have on a vehicle’s airflow varies from vehicle to vehicle. However, they are often discarded from race vehicles and high efficiency concepts in order to maintain the smallest possible coefficient of drag. A much more common option is to replace the windshield wipers with lower profile wipers, or to remove the windshield wiper on the passenger side of the vehicle. Alternatively, a deflector may be used to deflect the air up and over the wipers to reduce the drag coefficient. Another alternative is to equip the vehicle with a single wiper placed in the center of the windshield, allowing it to cover both sides of the windshield. This mitigates the amount of drag by decreasing the surface area of the blade. While the application of a single wiper blade is useful for performance level vehicles, a common street car would see only marginal improvements in both fuel efficiency and acceleration/speed.
[0007] In light of foregoing discussion, there is a need to develop a system for reducing aerodynamic drag on a vehicle, to overcome one or more limitations stated above.

SUMMARY OF THE DISCLOSURE

[0008] One or more drawbacks of drag reducing systems of the vehicles as described in the prior art are overcome, and additional advantages are provided through the system as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0009] In one non-limiting embodiment of the present disclosure, there is provided a hood assembly for reducing aerodynamic drag on a vehicle. The hood assembly comprises a hood adapted to rotate about a fixed point at a first end of an engine compartment in the vehicle, when a detected speed of the vehicle exceeds at least one of a plurality of pre-set speed values. One or more under-hood members are coupled to the hood at a second end of the engine compartment. The second end is closer to a windshield of the vehicle than the first end. The one or more under-hood members are adapted to move to at least a first position towards the windshield upon rotation of the hood. Further, one or more actuators are coupled to one or more of the hood and the one or more under-hood members. The one or more actuators are configured to rotate the hood, and/or deploy the one or more under-hood members towards at least the first position based on the detected speed of the vehicle.
[0010] In an embodiment of the present disclosure, the one or more actuators are interfaced with an on-board control unit in the vehicle. The on-board control unit is configured to receive one or more of the detected speed of the vehicle, define a desired angle of rotation of the hood and a desired position of each of the under-hood members between corresponding default positions and the windshield based on the one or more stored mappings
[0011] In an embodiment of the present disclosure, the one or more actuators are configured to rotate the hood, deploy the one or more under-hood members towards at least the first position, or a combination thereof, based on the measured speed and the stored mappings.
[0012] In an embodiment of the present disclosure, wherein the on-board control unit is further configured to measure the value of the aerodynamic performance parameters corresponding to the vehicle subsequent to one or more of the rotation of the hood and deployment of the one or more under-hood members as feedback. The on-board control unit operates the one or more actuators to further adjust a position of one or more of the hood and the one or more under-hood members based on the feedback to achieve the desired value of one or more aerodynamic performance parameters corresponding to the vehicle.
[0013] In an embodiment of the present disclosure, the one or more under-hood members comprise at least a first under-hood member and a second under-hood member. The one or more actuators are configured to position the first under-hood member and the second under-hood member at one or more positions between corresponding default positions under the hood and the windshield based on the measured speed of the vehicle and the stored mappings. The stored mappings are the data, which correlates the speed of the vehicle measured against related or user-specified vehicle performance parameters such as the fuel efficiency and other data like engine speed, calculated torque values, and the like, generated while the vehicle is on the move. To ensure that hood rotation provides best drag coefficient, the on-board computer provides instruction based on optimum value of the performance parameters under actual driving conditions. In one embodiment, the first under-hood member is stacked over the second under-hood member.
[0014] In an embodiment of the present disclosure, the one or more under-hood members comprise a single under-hood member that further comprises a plurality of segments. The one or more actuators are configured to selectively position each of the plurality of segments at one or more positions between corresponding default positions under the hood and the windshield based on the measured speed and the stored mappings.
[0015] In an embodiment of the present disclosure, the one or more actuators are configured to rotate a trailing edge of the hood upwards and away from a resting position of the trailing edge at the second end of the engine compartment based on the measured speed and the stored mappings.
[0016] In an embodiment of the present disclosure, the one or more actuators are configured to hold the hood in a rotated position, support the one or more under-hood members coupled to the underside of the hood, or a combination thereof
[0017] In an embodiment of the present disclosure, the one or more actuators are configured to rotate the hood back and retract the one or more under-hood members to corresponding default positions when the measured speed of the vehicle falls below one or more of the pre-set speed values.
[0018] In an embodiment of the present disclosure, the one or more actuators are configured to rotate the hood back and retract the one or more under-hood members to corresponding default positions when one or more wipers of the vehicle are actuated.
[0019] In an embodiment of the present disclosure, the one or more under-hood members are coupled to an underside of a trailing edge of the hood and hidden from view when vehicle is off to preserve an aesthetic design of an exterior of the vehicle.
[0020] In an embodiment of the present disclosure, the hood and the one or more under-hood members are deployed in a front portion of the vehicle, a rear portion of the vehicle, or a combination thereof.
[0021] In an embodiment of the present disclosure, the hood is adapted to rotate up to a predetermined angle without obstructing driver’s visibility.
[0022] In another non-limiting embodiment of the present disclosure, there is provided a method for reducing aerodynamic drag on a vehicle. The method comprising acts of measuring a speed of the vehicle, comparing one or more of the measured speed with a plurality of pre-set speed values. Further, the method comprises operating one or more actuators coupled to one or more of a hood and one or more under-hood members when a measured speed of the vehicle exceeds at least one of a plurality of pre-set speed values. The one or more actuators are configured to rotate the hood and deploy the one or more under-hood members to at least a first position towards a windshield of the vehicle, or a combination thereof, based on the measured speed of the vehicle.
[0023] In an embodiment of the present disclosure, the method comprises act of configuring the hood to rotate about a fixed point at a first end of an engine compartment in the vehicle, and coupling the one or more under-hood members to an under-side of the hood at or near a second end of the engine compartment.
[0024] In an embodiment of the present disclosure, the method comprises act of configuring one or more actuators to rotate the hood and deploy the one or more under-hood members to at least a first position towards the windshield based on one or more stored mappings in an on-board control unit in the vehicle.
[0025] In an embodiment of the present disclosure, the detected speed of the vehicle and one or more stored mappings define a desired angle of rotation of the hood and a desired position of each of the under-hood members between corresponding default positions and the windshield at different speeds of the vehicle for achieving a desired value of one or more aerodynamic performance parameters corresponding to the vehicle.
[0026] It is also understood that the onboard unit continuously tracks the vehicle speed and sometimes makes modifications to the angle of rotation to the hood to ensure that the benefits of the aero-dynamics is achieved, this may be slightly different from the pre-set values; in which the pre-set values may also be changed to reflect the adjustments made to the angle of rotation of the hood and the position of the under-hood members based on the measured feedback.
[0027] In an embodiment of the present disclosure, one or more aerodynamic performance parameters comprise one or more of aerodynamic drag coefficient, a downforce and a lift force.
[0028] In an embodiment of the present disclosure, the method comprises act of configuring the one or more actuators to rotate the hood back and retract the one or more under-hood members to corresponding default positions when the measured speed of the vehicle falls below one or more of the pre-set speed values.
[0029] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
[0030] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

[0031] Certain exemplary features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
[0032] FIG. 1 illustrates side view of a vehicle with a hood assembly for reducing aerodynamic drag, according to an exemplary embodiment of the present disclosure;
[0033] FIG. 2 illustrates an exemplary sectional view of the hood assembly of FIG. 1;
[0034] FIG. 3 illustrates an exemplary bottom view of the hood assembly of FIG. 1.
[0035] FIG. 4 illustrates an exemplary side view of the vehicle of FIG. 1 with the hood in resting position, according to an embodiment of the present disclosure;
[0036] FIG. 5 illustrates a schematic block diagram of the system for operating the hood assembly for reducing aerodynamic drag on the vehicle, according to an embodiment of the present disclosure; and
[0037] FIG. 6 illustrates a flowchart depicting an exemplary method for reducing aerodynamic drag on the vehicle, according to an embodiment of the present disclosure.
[0038] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

[0039] The foregoing has broadly outlined the features and technical advantages of the present disclosure such that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the concept and specific embodiments disclosed herein may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its assembly and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
[0040] Use of terms such as “comprises”, “comprising”, or any other variations thereof in the description, are intended to cover a non-exclusive inclusion, such that a system, assembly or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup, system, assembly, device or method. In other words, one or more elements in a setup, system, device or an assembly proceeded by “comprising… a” does not, without more constraints, preclude the existence of other elements or additional elements in the setup, system, device, or assembly.
[0041] To overcome one or more limitations stated in the background, the present disclosure provides a hood assembly for reducing aerodynamic drag on a vehicle (101), such as an automobile. An automobile, or a self-propelled vehicle (101), is subjected to aerodynamic drag force, lift force, and other aerodynamic forces when it moves on ground surface. The drag force tends to offer resistance to vehicle (101) propulsion, especially at high speeds. The drag force increases with an increase in momentum of the vehicle (101) due to size and weight of the vehicle (101) body acting against surrounding air.
[0042] The embodiments of the present system alter flow dynamics around the vehicle (101) body, and reduce drag force acting on the vehicle (101). Particularly, the system comprises a hood assembly that aids in improving aerodynamic performance of the vehicle (101). The assembly includes a hood adapted to rotate about a fixed point at a first end of an engine compartment of the vehicle (101). The hood can move between a closed position and an open position about the fixed point. The rotation of the hood takes place when the speed of the vehicle (101) exceeds at least one of a plurality of pre-set speed values, which will be explained in greater detail in the subsequent paragraphs of the detailed description.
[0043] Further, the hood assembly also includes one or more under-hood members coupled to the hood at or near a second end of the engine compartment. In one embodiment, the under-hood members are coupled to a free end of the hood, which is closer or proximal to windshield of the vehicle (101) than a fixed end of the hood that is closer to the headlights. The free end of the hood is also referred to as “trailing edge” of the hood from where the air leaves the surface of the hood to pass over the profile of the windshield. The rotation of the hood about the fixed point causes trailing end of the hood to lift or to be angularly displaced from its resting position. The rotation of the hood results in a decrease in windshield area, thereby reducing the aerodynamic drag experienced by the vehicle (101).
[0044] However, during such rotation of the hood, a gap will be formed between the hood and the vehicle (101) body, i.e., between the trailing end of the hood and the windshield that hinders air flowing over body of the vehicle (101). Accordingly, the one or more under-hood members may be selectively deployed to a first position towards the windshield to close this gap. The rotation of the hood from a closed position, and deployment of the one or more under-hood members upon rotation of the hood are achieved through one or more actuators depending on the measured speed of the vehicle (101).
[0045] In one embodiment, the closed position of the hood is a position when free end of the hood completely rests on the engine compartment so that the outer profile of the hood is suitably aligned with the profile of the engine compartment. In alternate terms, when the hood is in closed position, there is no noticeable gap formed between the hood and the windshield of the vehicle (101), as well between the hood and the engine compartment, when viewed from vehicle (101) door side. When the hood is in rotated position, the hood is angularly spaced from the engine compartment to form a gap between its free end and the windshield. Throughout the specification, the term “closed position” of the hood is referred to as “resting position” of the hood for the sake of clarity. Additionally, the un-deployed condition of one or more under-hood members accommodated under the hood when the hood is in “resting position” is referred to as “default position” of the under-hood members for the sake of clarity.
[0046] In certain embodiments, the one or more actuators are coupled or interfaced with an on-board control unit to effect and control the rotation of the hood from a resting position to a rotated position, as well as to deploy the one or more under-hood members from the free end of the hood. In one embodiment, the on-board control unit is configured to receive signals relating to measured speed of the vehicle (101) from at least one sensor, such as but not limiting to a vehicle (101) speed sensor. The received signal, indicative of the detected vehicle (101) speed, is compared with a plurality of pre-set speed values, for example, stored in the on-board control unit. In one embodiment, the on-board control unit also contains stored mappings that define different angles of rotation of the hood, and desired positions to which each of the under-hood members is moved or deployed from a corresponding default position. Specifically, the mappings define suitable values for hood rotation and position of under-hood members at different speeds of the vehicle (101) for providing optimal aerodynamic performance.
[0047] Based on the measured speed and the stored mappings, the one or more actuators are configured by the on-board control unit to rotate the hood through a predetermined angle to a desired position. This takes place when the measured speed value, which is being compared, is greater than at least one of a plurality of pre-set speed values stored in the on-board control unit. Depending on the rotation of the hood to a desired position, the one or more under-hood members are moved or deployed to the first position towards the windshield of the vehicle (101) as per the stored mappings. The deployment or movement of the one or more under-hood members towards the windshield of the vehicle (101) conceals a gap formed between free end of the hood and the windshield of the vehicle (101) when the hood is rotated to the desired position.
[0048] As previously noted, any gap formed between the windshield and the hood may impede the flow of the air along the vehicle (101) body. Deployment of the under-hood members closes the gap, thus providing a near continuous surface that allows for more laminar flow of air over the vehicle (101) body. Accordingly, in an embodiment of the present disclosure, the hood assembly includes at least a first under-hood member and a second under-hood member, with the first under-hood member being stacked over the second under-hood member. The one or more actuators of the hood assembly are configured to position or move the first under-hood member and the second under-hood member to one or more positions between corresponding default positions under the hood and the windshield depending on the measured speed of the vehicle (101) and the stored mappings in the on-board control unit. In an alternative embodiment, however, a single under-hood member including a plurality of segments may be provided to close the gap. In such an embodiment, the one or more actuators of the hood assembly are configured to position or move each of the plurality of segments at one or more positions between corresponding default positions under the hood and the windshield depending on the measured speed of the vehicle (101) and the stored mappings in the on-board control unit.
[0049] Further, the on-board control unit is also involved in measuring the value of the aerodynamic performance parameters corresponding to the vehicle (101) subsequent to one or more of the rotation of the hood and deployment of the under-hood members as feedback. Thereafter, the feedback signal is used by the on-board control unit to configure the actuators to further adjust a position of the hood and the under-hood members to achieve the desired value of one or more aerodynamic performance parameters corresponding to the vehicle (101). In an embodiment, the aerodynamic performance parameters comprise one or more of aerodynamic drag coefficient, a downforce, and a lift force.
[0050] Furthermore, the one or more actuators outlined in the above paragraphs are configured to hold the hood in a rotated position, and support the under-hood members coupled to the underside of the hood. Also, the one or more actuators are configured to rotate the hood back and retract the one or more under-hood members to previous or corresponding default positions when the measured speed of the vehicle (101) falls below one or more of the pre-set speed values. In another embodiment of the present disclosure, the one or more actuators are configured to rotate the hood back to a resting position and retract the one or more under-hood members to corresponding default positions when one or more wipers of the vehicle (101) are actuated. This prevents interference between operation of wipers and deployment of the under-hood members when the windshield is to be cleaned while on the vehicle (101) is on the move.
[0051] Reference will now be made to an assembly for reducing aerodynamic drag on a vehicle (101), which is explained with the help of figures. The figures are for the purpose of illustration only and should not be construed as limitations on the assembly. Wherever possible, referral numerals will be used to refer to the same or like parts. It is to be noted that the vehicle (101) shown in the drawings of the present disclosure is solely for the purpose of illustration and simplicity, and should not be construed as limitation to the system, assembly and the method disclosed in embodiments of the present disclosure. A person skilled in the art can envisage any other vehicle (101) to have incorporated or encompassed with the assembly disclosed in the embodiments of the present disclosure.
[0052] FIG. 1 illustrates an exemplary side view of a vehicle (101) including a hood assembly (100) for reducing aerodynamic drag on the vehicle (101). Aerodynamic drag, as explained herein, reduces drivability, mobility and fuel economy of the vehicle (101). The hood assembly (100), disclosed in the embodiments of the present disclosure, is configured to achieve desired value of the aerodynamic performance parameters of the vehicle (101). In one embodiment, the aerodynamic performance parameters comprise one or more of an aerodynamic drag coefficient, a desired downforce, and a desired lift force. The reduction of aerodynamic drag force acting on the vehicle (101) improves drivability and mobility, as well as improves fuel economy of the vehicle (101).
[0053] As shown in FIG. 1, the vehicle (101) comprises a body, including the windshield (101A), whose surface or profile is exposed to air. The direction of air flow over the vehicle (101) body and the windshield (101A) when the vehicle (101) moves in forward direction is depicted by arrows. The extent of drag force acting on the vehicle (101) depends on three critical parameters, viz. the mass density of air, velocity of the vehicle (101) moving relative to air flow and area of vehicle (101) exposed to air. The only variable among the above mentioned parameters is velocity of the vehicle (101) with respect to air flow. As the velocity increases, drag force acting on the vehicle (101) increases and vice-versa. In one embodiment, the drag force acting on the vehicle (101) is quantified in terms of a drag coefficient value. The term drag co-efficient used herein refers to a quantity which correlates the drag force with mass density of air, velocity of the vehicle (101) moving relative to air flow, and the exposed area of the vehicle (101). Generally, a higher value of drag co-efficient denotes a higher magnitude of drag force acting on the vehicle (101), which in turn, indicates reduced drivability, mobility, and fuel economy of the vehicle (101).
[0054] Motor vehicles, as well known in the art, comprise an engine compartment (102) which is typically located at the frontal end of the vehicle (101). The engine compartment (102) houses the engine and other related components of the vehicle (101). The engine compartment (102) is further provided with a hood (103) which covers the engine compartment (102) on the top. The hood (103) can be opened to provide access to the engine compartment (102) for inspection and maintenance purposes. When there is no requirement of maintenance and inspection, the hood (103) is disposed in the closed or resting position. In the normal resting position of the hood (103), the outer profile of the hood (103) suitably aligns with the outer profile of the engine compartment (102) so that the engine compartment (102) is completely concealed and aesthetically appealing.
[0055] When the vehicle (101) moves in forward direction at any speed, a layer of air flows over the outer profile of the hood (103), and thereafter, over the windshield to finally leave the trailing edge of the vehicle (101). The front end of the vehicle (101) proximal to front headlight or front bumper serves as leading edge for air flow, and rear end proximal to tail lights or rear bumper of the vehicle (101) serves as trailing edge from where the air leaves the vehicle (101) surface. During such motion of the vehicle (101), the layer of air offers resistance or aerodynamic drag to forward movement of the vehicle (101. The vehicle (101) experiences lift force and downforce in directions perpendicular to the drag force, in addition to the drag force.
[0056] According to certain aspects of the present disclosure, the hood assembly (100) is configured to reduce aerodynamic drag force acting on the vehicle (101), thereby improving aerodynamic characteristics of the vehicle (101). The assembly (100), as shown in FIG. 1, comprises a hood (103) adapted to rotate about a fixed point at a first end (102A) of the engine compartment (102).The hood assembly (100), comprising the hood (103), is assembled above the engine compartment (102) to cover and protect the engine and other components present inside the engine compartment (102) from external loads, environmental parameters etc. In an embodiment of the disclosure, an additional hood assembly, similar to the hood assembly (100) can be provided in one or more other positions of the vehicle (101) such as but not limited to rear body of the vehicle (101), which functions as a spoiler and is deployed as the vehicle (101) slows down.
[0057] In one embodiment, the hood (103) is pivotally connected to the first end (102A) of the engine compartment (102) proximal to the front bumper (101B) of the vehicle (101). In one embodiment, the end of the hood (103) that is connected through a hinge to the first end (102A) of the engine compartment is referred to as hinged end (103A) of the hood (103). The hinged end (103A) serves as leading edge for allowing the flow of air over the vehicle (101) body and the windshield (101A). The opposite end (103B) of the hood (103) is free and can rotate about the fixed point at the first end (102A) of the engine compartment. The hinged (or pivotal) connection of the hood (103) which allows the hood (103) to be rotated to serve the purpose of reducing aerodynamic drag will be explained in detail with reference to FIG. 2.
[0058] FIG. 2 illustrates an exemplary sectional side view of the hood assembly (100) of FIG. 1. As described with reference to FIG. 1, the hood (103) can rotate about a fixed point associated with the hinge member to allow the free end (103B) of the hood (103) to rise from the resting position. The rising of the free end (103B) of the hood (103) allows the air to flow seamlessly over the windshield (101A) of the vehicle (101) during its forward motion. The free end (103B) of the hood (103) is alternatively referred to as trailing edge (103B) of the hood (103) for the sake of clarity throughout the detailed description.
[0059] Generally, in normal resting position of the hood (103), the trailing edge (103B) facilitates flow of air over the, windshield (101A), and subsequently over rear portion of the vehicle (101) body. The air striking the vehicle (101) body and the windshield (101A) imposes air resistance on the vehicle (101). The magnitude of air resistance or concentration of drag force is significantly high at the bottom edge of the windshield (101A) where trailing edge (103B) of the hood (103) meets the windshield (101A). To mitigate the effects of air resistance on the vehicle (101) body and the windshield (101A), the free end (103B) of the hood (103) is configured to rotate about the fixed point at a first end (102A) of the engine compartment (102). Additionally, one or more under-hood members (105) positioned at the second end (102B) of the engine compartment (102) are deployed towards the windshield (101A) to provide a continuous surface that allows for a more laminar air flow along the vehicle (101) body.
[0060] More particularly, when the vehicle (101) moves in air, the trailing edge (103B) of the hood (103) is angularly lifted about the fixed point so that the outer profile of the hood (103) forms a continuous surface that allows for smoother airflow over the profile of the windshield (101A). Rotation of the hood (103) simultaneously deploys the one or more under-hood members (105) towards the windshield (101A) to ensure continuity between the outer profile of the hood (103) and the profile of the windshield (101A). The likely continuity between outer profiles of the hood (103) and the windshield (101A) allows air to seamlessly pass over the vehicle body, thus reducing aerodynamic drag acting on the vehicle (101).
[0061] In another embodiment of the present disclosure, the hood (103) may be composed of a plurality of inter-connected or inter-linked pieces or sections that provide the functionality of the under-hood members (105). Accordingly, different sections of the hood (103) may be connected to each other via a pivoted joint that allow the sections to be actuated through actuators s to slide over each other. The sliding action aids in seamless flow of air over the windshield (101A), thereby enhancing aerodynamics of the vehicle (101).
[0062] In certain embodiments, the hood assembly (100) comprising a hood (103) and one or more under-hood members (105) may also be provided at a rear portion (106) of the vehicle (101) to provide functionality similar to a spoiler. The hood (103) is hinged or pivoted at the rear end (102D) of the rear portion (106) disposed at or near tail lamps or rear bumper (101D) of the vehicle (101). This hinged connection at the rear end (102D) allows a free end of the hood (103) proximal to rear windshield (101C) [i.e. at end (102D)] to rotate about the rear end (102D), as depicted by the arrow. In addition, one or more under-hood members (105) are coupled to the free end of the hood (103) so that they can be deployed towards the rear windshield (101C) of the vehicle (101) upon hood (103) rotation. The rotation of the hood (103) and the deployment of under-hood members (105) towards the rear windshield (101C) ensure continuity between the outer profile of the hood (103) and the profile of the rear windshield (101C). The continuity between outer profile of the hood (103) and profile of the windshield (101A) allows air to seamlessly pass over the vehicle (101) body, which increases aerodynamic drag, thereby providing greater grip on the road for tires by acting on the rear portion (106) of the vehicle (101).
[0063] As previously noted, the rotation of hood (103) about the fixed point at the first end (102A) is facilitated by one or more actuators (104) coupled to the engine compartment (102) of the vehicle (101). The one or more actuators (104) are configured to rotate or move the hood (103) between a closed position and an open position about the hinge member upon actuation by the one or more actuators (104). In one embodiment, the closed position of the hood (103) corresponds to a position where the profile of the hood (103) completely covers the engine compartment (102) without providing any visibility to inside of the engine compartment (102) when viewed from outside. Furthermore, in the closed position, the outer surface of the hood (103) remains suitably aligned with the profile of the engine compartment (102). The closed position of the hood (103) also restricts access to inside of the engine compartment (102). On the other hand, open position of the hood (103) refers to a position where the hood (103) is rotated to angularly move away from the engine compartment (102) so that a gap is formed between the trailing edge (103B) of the hood (103) and the windshield (101A).
[0064] In certain embodiments, the hinge member of the hood assembly (100) is configured to restrict a maximum angle of opening of the hood (103) to a limited range of motion so that visibility of the driver is not affected during rotation of the hood (103). The angular movement or rotation of the hood (103) about the hinge member actuated by the one or more actuators (104) lifts the profile of the hood (103) and positions the outer profile of the hood (103) with the outer profile of the windshield (101A). This positioning of the outer profiles of the rotated hood (103) and the windshield (101A) allows the air flowing over the outer profile of the hood (103) to seamlessly pass over the windshield (101A).
[0065] In one embodiment, the angle of rotation of the hood (103) by the one or more actuator (104) is selected based on a measured speed at which the vehicle (101) moves in forward direction. To decide the angle of rotation of the hood (103), the actuators (104) are interfaced with an on-board control unit (108) (see FIG. 5) in the vehicle (101). The on-board control unit (108) is operatively coupled to one or more sensors, including but not limited to vehicle (101) speed sensors to receive signals relating to a measured speed of the vehicle (101). The on-board control unit (108) compares the measured speed with a plurality of pre-set speed values stored in an associated memory unit (108A), for example, as shown in FIG. 5.
[0066] When the measured speed value exceeds at least one of a plurality of pre-set speed value stored in the on-board control unit (108), the actuators (104) are actuated to rotate the trailing edge (103B) of the hood (103) about the fixed point at the first end (102A). Specifically, the trailing edge (103B) is rotated by a designated angle that positions the hood (103) to provide a more aerodynamic profile for smoother air flow over the vehicle (101) body during high speed motion. In one embodiment, the on-board control unit (108) retrieves the designated angle of rotation for the measured speed value from stored mappings that correlate the vehicle (101) speed with corresponding angular rotation that has previously been determined to provide a desired aerodynamic performance, for example, a desired drag coefficient value, for the vehicle (101).
[0067] However, as previously noted, the rotation of the hood (103) may result in a gap between the windshield (101A) and the trailing edge (103B) of the hood (103). This gap may disrupt the airflow over the vehicle (101) body. Accordingly, the hood assembly (100) comprises one or more under-hood members (105) coupled to the trailing edge (103B) of the hood (103) and configured to slide towards the windshield (101A) to cover the gap, thereby providing an improved aerodynamic profile for smoother airflow over the vehicle (101) body. To that end, in one embodiment, the one or more under-hood members (105) are positioned under the hood (103) at its trailing edge (103B). In an alternate embodiment, however, the one or more under-hood members (105) are telescopically arranged at the free end or trailing edge (103B) of the hood (103) for telescopic deployment towards the windshield (101A).
[0068] According to certain aspects of the present disclosure, the deployment of the one or more under-hood members (105) is proportional to the angle of rotation of the hood (103), and in turn, the vehicle (101) speed. To that end, the one or more under-hood members (105) are operatively coupled to the hood (103) at the trailing edge (103B), for example via mechanical and/or electronic means. Particularly, one or more of the under-hood members (105) are operatively coupled to the hood (103) such that as soon as the hood (103) rotates through a given angle, one or more of the under-hood members (105) are deployed towards the windshield (101A) by a distance specified in the stored mappings. The specified distance is predetermined such that deployment of the under-hood members (105) conceals at least a portion of the gap formed due to rotation of the hood (103).
[0069] Accordingly, in one embodiment, the one or more under-hood members (105), positioned underneath the hood (103) at the trailing edge (103B) of the hood (103), are deployed or moved to a first position towards the windshield (101A). Particularly, the under-hood members (105) are deployed when the trailing edge (103B) of the hood (103) is raised from the resting position as and when the measured speed of the vehicle (101) exceeds one of a plurality of pre-set speed values stored in the on-board control unit (108).
[0070] In one embodiment, the second under-hood member (105B) is positioned relative to the first under-hood member (105A) in such a way that the first under-hood member (105A) is stacked over the second under-hood member (105B). This arrangement allows the first under-hood member (105A) to be deployed to at least a first position towards the vehicle (101) windshield (101A), and optionally the second under-hood member (105B) to be deployed further from the first position towards the windshield (101A).
[0071] Particularly, when the measured speed of the vehicle (101) exceeds one of a plurality of pre-set speed values, the on-board control unit (108) queries the stored mappings to identify a suitable angle of rotation of the hood (103) and the positions of the under-hood members (105A, 105B) that are known to provide desired aerodynamic performance. The on-board control unit (108) subsequently sends signals corresponding to the identified angle of rotation of the hood (103) and the positions of the under-hood members (105A, 105B) to the one or more actuators (104). Based on the received signals, the actuators (104) are actuated to rotate the hood (103) away from its resting position through the identified angle, say a first angle. In certain embodiments, the rotation of the hood (103) and deployment of the under-hood members (105) are effected by two separate sets of actuators (104) interfaced with the on-board control unit (108).
[0072] In one embodiment, as the hood (103) is rotated, the first under-hood member (105A) may simultaneously be moved or deployed towards the windshield (101A) to conceal at least a portion of the gap formed between the trailing edge (103B) of the rotated hood (103) and the windshield (101A). Thus, the hood (103) is rotated to a first desired position away from the resting position when the speed of the vehicle (101) exceeds a first pre-set value of a plurality of pre-set speed values stored in the on-board control unit (108). Upon rotation of the hood (103) to the first desired position, the first under-hood member (105A) is deployed to a first position towards the windshield (101A). In the first position, the first under-hood member (105A) is configured to partially or completely conceal the gap formed between the trailing edge (103B) of the hood (103) and the windshield (101A). For small angles of rotation of the hood (103), the air turbulence could be minimal and do not necessitate deployment of the under-hood member (105A). Accordingly, in one embodiment, the under-hood member (105A) may not be deployed when the hood (103) is in the first desired position. However, in certain other embodiments, the deployment of first under-hood member (105A) to the first position towards the windshield (101A) mitigates the effect of air turbulence, thereby improving vehicle (101) aerodynamics.
[0073] With a further increase in speed of the vehicle (101), and when the measured speed exceeds a second pre-set value, which is higher than the first pre-set speed value, the hood (103) may be rotated further, say through a second angle. The second angle of the hood (103) being greater than the first angle decreases effects of air turbulence on the vehicle (101). However, in the second angular position of the hood (103), a second or a further gap is formed between the already extended (or deployed) first under-hood member (105A) and the windshield (101A), which increases the air turbulence closer to the windshield (101A). To conceal this subsequently formed gap, the second under-hood member (105B) positioned relative to the first under-hood member (105A) is deployed towards the vehicle (101) windshield (101A) by the one or more actuators (104). The deployment or movement of the second under-hood member (105B), in one embodiment, completely conceals the gap.
[0074] Concealing the gap by deployment of the under-hood members (105) prevents localization or concentration of air in the gap formed between the windshield (101A) and trailing edge (103B) of the hood (103), thus allowing the air to seamlessly pass over the windshield (101A). The rotated hood (103) and the deployed under-hood members (105) also prevent air turbulence that may occur due to disruption in a natural path of air flowing from the hood (103) towards the windshield (101A) caused by the gap. The combined effect of hood (103) rotation and deployment of one or more under-hood members (105) makes the airflow over the hood (103) much more laminar and smooth as the air flows over a continuous surface from the windshield (101A) to the roof of the vehicle (101).
[0075] Moreover, use of two under-hood members (105A, 105B) instead of single under-hood member to close the gap formed between the rotated hood (103) and the windshield (101A) provides enhanced aerodynamic performance in certain scenarios. For example, when the vehicle (101) moves at higher speeds, especially sporty vehicles where speed and aerodynamics are of greater interest, time taken to improve the aerodynamic characteristics is of utmost importance. Even a small reduction in time taken to improve aerodynamics of the vehicles results in significant improvements in mobility, drivability, and fuel economy of the vehicle (101). If only a single under-hood member is employed to conceal the gap formed between a rotated hood and the windshield, the amount of time taken to conceal the gap may be more at high speeds. This is because, at very high speeds, the single under-hood member has to move a greater distance in order to close the gap formed between the rotated hood and the windshield. Any delay or lag in deployment of the single under-hood member at high speeds will result in reduction in mobility and fuel economy of the vehicle (101).
[0076] Hence, the present disclosure employs two or more under-hood members that can be deployed simultaneously, successively, or incrementally, in response to rotation of the hood (103) to conceal the gaps formed between the trailing edge (103B) of the hood (103) and the windshield (101A) at different speed ranges. However, one should not consider use of two or more under-hood members as limitation to the present disclosure, as one can use only a single under-hood member without deviating from the scope of the present disclosure. Certain exemplary implementations for deployment of the under-hood members (105A, 105B) in various scenarios during motion of the vehicle (101) are presented with reference to Tables 1 and 2:

Table 1 - Implementation 1
Position First speed range Second speed range
Hood Rotates based on vehicle (101) speed No further rotation

First under-hood
Member Deploys and at least partially covers a gap formed between the rotated hood and the windshield No further deployment
Second under-hood member No deployment Deploys to cover the gap completely

[0077] In the implementation depicted in Table 1, the hood (103) is rotated to a first angular position corresponding to a measured speed of the vehicle (101) based on the stored mappings. The gap formed between the hood (103) in the first angular position and the windshield (101A) is at least partially concealed by the deployment of first under-hood member (105A) towards the windshield (101A). With a further increase in speed of the vehicle (101), the hood (103) remains in the first angular position and the first under-hood member (105A) remains in the deployed condition. During this time, second under-hood member (105B) that is positioned below the first under-hood member (105A) at the trailing edge (103B) is actuated and adapted to cover the remaining gap between the trailing edge (103B) and the windshield (101A). In this circumstance, the second under-hood member (105B) travels a distance lesser than the distance that would have been covered by a single under-hood cover, and closes a gap between the first under-hood cover (105A) that is already extended and the windshield (101A). Therefore, the time taken by the second under-hood member (105B) to close a gap between the already deployed first under-hood member (105A) and the windshield (101A) is lesser than the time taken if a single under-hood member had been employed to move to close a gap between the hood (103) and the windshield (101A). Thus, deploying two under-hood members reduces time taken to achieve aerodynamics in vehicles operated at higher speeds.
[0078] Table 2 depicts another implementation having alternative positioning of the first under-hood member (105A) and the second under-hood member (10B).

Table 2 - Implementation 2
Position First speed range Second speed range
Hood Rotates by a first angle based on stored mappings Rotates further to a second angle based on the stored mappings

First under-hood
member Deploys and completely covers a gap formed between the rotated hood and the windshield Deploys incrementally corresponding to further rotation of the hood

Second under-hood member The second under-hood-member moves along with first under-hood member based on input from the on-board control unit, which decides the final target. Deploys to fill a successive gap formed between the first under-hood member and the windshield.

[0079] In the implementation depicted in Table 2, once the vehicle (101) starts moving within a first speed range, the hood (103) rotates by a first angle defined for a first speed range as per the stored mappings. Rotation of hood (103) through the first angle creates a first gap between the trailing edge (103B) and the windshield (101A). The first under-hood member (105A) is actuated or deployed to cover the first gap completely. Also, based on inputs from the on-board control unit (108), the second under-hood member (105B) may be deployed to conceal the gap. In one embodiment, the movement of the first under-hood member (105A) towards the windshield (101A) also carries the second under-hood member (105B) with it towards the windshield (101A). This dynamic movement aids in reducing the time for a further deployment of the second under-hood member (105B).
[0080] When vehicle (101) speed increases/decreases to a second speed range (which is greater/lesser than first speed range), the hood (103) rotates further to a second angle defined for the second speed range as per the stored mappings. Rotation of hood (103) through the second angle creates a further gap (of a greater or lesser size) between the deployed first under-hood member (105A) and the windshield (101A). Under such a condition, the first under-hood member (105A) may further extend towards/retract from the windshield (101A) corresponding to second angle rotation of the hood (103). Additionally, the second under-hood member (105B) may deploy from the deployed position of the first under-hood member (105A) to cover the gap formed between the already deployed first under-hood member (105A) and the windshield (101A). With furthermore rotation of the hood (103), the first under-hood member (105A) may undergo further incremental movement along with second under-hood member (105B) to completely cover successive gaps formed ahead of the trailing edge (103B), thus achieving improved aerodynamic characteristics of the vehicle (101).
[0081] In an alternative embodiment, the hood assembly (100) includes only one under-hood member (105A), that includes a plurality of segments disposed on underside of the trailing edge (103B) of the hood (103). The deployment of the plurality of segments of the under-hood member (105A) is similar to implementations 1 and 2 described above, where the deployment of each segment of the under-hood member (105A) is identical with the deployment of first under-hood member and the deployment of second under-hood member. More specifically, the deployment of each of the plurality of segments of the under-hood member (105A) will take place in a sequential or telescopic manner proportional to rotation of the hood (103) that is initiated in response to a measured speed of the vehicle (101), when the speed exceeds at least one of the pre-set speed values.
[0082] Rotation of the hood (103) and deployment of one or more under-hood members (105) results in a more laminar and smoother flow of air over a continuous surface from the windshield (101A) to the roof of the vehicle (101). Improvement in the aerodynamic performance, in turn, results in improved fuel efficiency, higher speeds, enhanced safety, reduced drag force, and the like.
[0083] Moreover, in certain embodiments, the hood (103) and the under-hood members (105) are fabricated using suitable lightweight materials to limit addition of extra weight to the vehicle (101). In one embodiment, for example, the hood (103) may be made of any known material such as metals and alloys including steel, aluminum, carbon fiber, fiber reinforced plastic (FRP), etc. The under-hood members (105) may be made of materials like steel, carbon fiber, FRP, and the like. However, edges of the under-hood members (105) may be made of relatively softer material that does not damage windshield (101A), like ethylene propylene diene monomer rubber (EPDM), Polypropylene, plastic, carbon fiber, soft metals, and the like, to prevent damage to the windshield (101A) and to ensure proper sealing between the edges and the windshield (101A). Moreover, the edges of the under-hood members (105) that move towards the windshield (101A) may also be suitably shaped with respect to the shape of the windshield (101) to aids in improving aerodynamics.
[0084] FIG. 3 illustrates an exemplary sectional bottom view of the hood assembly (100) of FIG. 2 including the one or more under-hood members (105). Particularly, in the embodiment depicted in FIG. 3, the hood assembly (100) includes a first under-hood member (105A) and a second under-hood member (105B). In another embodiment, only a single under-hood member (105) comprising a plurality of segments (105A, 105B) may be provided on the underside of the trailing edge (103B) of the hood (103).
[0085] Each of the one or more under-hood members (105) (or segments) may be operatively coupled to the one or more actuators (104that may be provided on either side of the engine compartment (102) for effective deployment. Particularly, in one embodiment, the two actuators (104) may be coupled to each of the first and second under-hood members (105A, 105B) for deployment towards the windshield (101A). However, one should note that the number of actuators (104) illustrated in FIGS. 2 and 3 are for the purposes of illustration only and that any number of actuators (104) can be connected to the under-hood members (105). Similarly, any number of actuators (104) may be operatively coupled to the hood (103), for example via electromechanical means, to rotate the hood (103) depending on measured speed of the vehicle (101) and the stored mappings. In certain embodiments, the actuators (104) are positioned under the hood (103) such that the actuators (104) are not visible when viewed from top. In certain embodiments, the under-hood members (105) may be visible from the top when they are deployed beyond the trailing edge (103B) of the hood (103) towards the windshield (101A). However, the under-hood members (105) are deployed such that, even when visible, the under-hood members (105) do not protrude obtrusively from the contour of the vehicle (101), without majorly affecting the aesthetic design of the exterior of the vehicle (101).
[0086] Apart from reducing aerodynamic drag and preserving aesthetics of the vehicle (101), use of the hood assembly (100) ensures safety of the vehicle (101), as well as of the passengers inside the vehicle (101). Generally, the hood (103) comprises sidewalls integrally formed on the sides of the hood (103). In the resting position, the sidewalls of the hood (103) reside inside the engine compartment (102) and will not be visible to the observer from either side. However, when the speed of the vehicle (101) increases, the actuators (104) rotate the hood (103) and deploy the under-hood members (105) towards the windshield (101A). In such a scenario, the sidewalls are configured to rotate along with the hood (103) and continue to conceal the engine compartment (102) from both sides.
[0087] Additionally, the gap created in front of the windshield (101A) by rotation of the hood (103) is concealed by the under-hood members (105). Concealment of this gap using the under-hood members (105) guards against entry of foreign matter into the vehicle (101) from above the engine compartment (102). Additionally, the under-hood members (105) are positioned below the hood (103) to ensure that safety of the vehicle (101) and around the vehicle (101) is not compromised whilst the members (105) are moving. Assuming that the under-hood members (105) were on top and moving, there are chances that objects like plastic covers, stones etc. may cause damage to the hood assembly (100) or get stuck between under-hood members (105), leading to undesirable outcomes.
[0088] Moreover, in certain embodiments, the lengths of the two under-hood members (105A, 105B) are suitably adjusted to enable them to reach the car windshield (101A) depending on the angles of rotation of the hood (103). Having two under-hood members (105A, 105B) also ensures that only at highest speeds, both the members (105A, 105B) are fully deployed. In certain other embodiments, the gap formed between the rotated hood (103) and the windshield (101A) may be further concealed by flexible fairings. These flexible fairings may be actuated with or without the use of the actuators (104).
[0089] In one embodiment, the actuators (104) are used not only to support the movement of under-hood members (105), but also to ensure stability during deployment of these members (105) at high vehicle (101) speeds. The actuators (104) also hold the hood (103) rigidly when the hood (103) is rotated to different angular positions and support the weights of one or more under-hood members (105) positioned at the underside of the hood (103). To that end, the one or more actuators (104), for example, include one or more mechanical, electro-mechanical, hydraulic, magnetic, and/or pneumatic actuators that can have linear or rotary motion to rotate the hood (103) and deploy the one or more under-hood members (105) towards the windshield (101A). In certain embodiments, these actuators (104) may be connected electronically to support the hood (103), prevent the deployed under-hood members (105) from sagging at the trailing edge (103B) of the hood (103), and to allow the actuators (104) to withstand the combined loads.
[0090] In an alternative embodiment, however, the rotation of the hood (103) is enabled by one or more motors with or without gearing which can take inputs from one or more speed sensors provided in the vehicle (101). The angle of rotation of the hood (103) is also limited between 0 degrees and ‘X’ degrees, where ‘X’ degree is a maximum specified angle of rotation of the hood (103) that does not affect the visibility of the driver. In one implementation, for example, the angle of rotation of the hood (103) may vary from about 0 degrees to about 85 degrees. Additionally, in some embodiments, the on-board control unit (108) prevents the movement or deployment of the under-hood members (105) during the operation of windshield wipers. This facilitates hassle free operation of the wipers to clear the windshield (101) for better visibility. Further, when speed of the vehicle (101) decreases or when the vehicle (101) comes to rest, the under-hood members (105) are retracted back to default positions under the trailing edge (103B) of the hood (103) by means of the one or more actuators (104). Additionally, the hood (103) also rotates to its original, default, zero, or the resting position, which is also referred to as an un-deployed or retracted hood mode.
[0091] FIG. 4 illustrates an exemplary side view of the vehicle (101) with hood (103) in closed position or resting position. As previously noted, the hood (103) is rotated through an angle about the fixed point only when the measured speed of the vehicle (101) exceeds one of a plurality of pre-set speed values stored in the on-board control unit (108), depending on the stored mappings. But when measured speed of the vehicle (101) is lesser than pre-set speed level or when the vehicle (101) is stationary, the hood (103) remains in closed condition or resting condition or default condition on the engine compartment (102). The closed position or resting position of the hood (103) is considered as zero degree position of the hood (103) and corresponds to default positions of the under-hood members (105). Thus, in resting position of the hood (103), the under-hood members (105) remain in un-deployed condition so that they are not visible beyond the trailing edge (103B) of the hood (103) when viewed from top or sides. Further, when the vehicle (101) is stationary, the appearance of the hood (103) is normal as in every other vehicle (101). This arrangement ensures there are no compromises in aesthetics of the vehicle (101) as the. under-hood members (105) are hidden or not visible in a closed hood (103) position.
[0092] Further, FIG. 5 illustrates a schematic block diagram of an exemplary system (500) for reducing aerodynamic drag. As shown in FIG. 5, the system (500) comprises the hood assembly (100) described with reference to FIGs. 1-4. As previously noted, the hood assembly (100) includes the hood (103) adapted to rotate between a closed position and an open position about a fixed point at a first end (102A) of an engine compartment (102) of the vehicle (101). The rotation of the hood (103) takes place when the speed of the vehicle (101) exceeds at least one of a plurality of pre-set speed values. The plurality of pre-set speed values is stored, for example in the memory unit (108A) in the on-board control unit (108) of the system (500). These pre-set speed values are readily available for comparison with the speed at which the vehicle (101) moves forward.
[0093] In addition, the memory unit (108A) is also configured to store one or more mappings, which determine the angle of rotation of free end (or trailing edge) (103B) of the hood (103) depending on comparison of vehicle (101) speeds with pre-set speed values. The speed of the vehicle (101) is measured by one or more sensors. The vehicle (101) speed values, thus detected, are fed as inputs to the on-board control unit (108). Upon receiving the inputs, the on-board control unit (108) compares the input speed values with the pre-set speed values in the memory unit (108A). When the vehicle (101) speed exceeds one of the pre-set speed values stored in the memory unit (108A), then the hood (103) is rotated by one or more of the actuators (104) to an angle specified in the stored mappings. Accordingly, for different speed values of the vehicle (101) that exceed one or more of the plurality of pre-set speed values stored in memory of the control unit (108), the hood (103) is rotated by different angles. The rotation of the trailing edge (103B) of the hood (103) creates a gap between the windshield (101A) and the trailing edge (103B), and the gap increases proportionately with the increase in angle of rotation. This gap is concealed via deployment of the under-hood members (105) coupled to underside of the trailing edge (103B) of the hood (103) for improved vehicle (101) aerodynamics.
[0094] As soon as the hood (103) rotates to one or more angular positions about the fixed end, the one or more under-hood members (105) are moved or deployed towards the windshield (101A) to conceal the gap. With successive rotations of the hood (103), the one or more under-hood members (105) may be successively deployed towards the windshield (101A). Particularly, in one embodiment, the gap between the windshield and the rotating hood is closed by under-hood members (105) by taking into account the extension of the hood (103). The extension of the hood (103) is measured, for example, by determining the actuator’s piston position and the known windshield angle of the vehicle (101). Rotation of the hood (103) and such intelligent deployment of the under-hood members (105) significantly reduce the aerodynamic drag experienced by the vehicle (101).
[0095] FIG. 6 illustrates a flowchart (600) depicting an exemplary method for reducing aerodynamic drag using the hood assembly (100) described with reference to FIGs. 1-5. At step 601, a speed of the vehicle (101) is measured using the one or more speed sensors that are interfaced to the on-board control unit (108). In one embodiment, the speed sensors include, but are not limited to, electro-mechanical, electronic and optical speed sensors. Further, at step 602, the speed of the vehicle (101) measured by the speed sensors is compared with a plurality of pre-set speed values stored in the on-board control unit (108). To that end, the on-board control unit (108) includes, but is not limited to, an Electronic Control Unit (ECU) of the vehicle (101), or a microprocessor based controller that can be interfaced with electro-mechanical components of the vehicle (101).
[0096] Upon measuring the speed of the vehicle (101), the on-board control unit (108) compares the speed values with the pre-set speed values in the memory unit (108A). If the measured speed is less than the pre-set values, at step 603, the hood assembly (100) continues to operate in the last known mode. However, if the measured speed is greater than the pre-set values, at step 604, the on-board control unit (108) determines the angle at which the hood (103) is to be rotated and the positions to which the under-hood members are to be moved based on the stored mappings. As previously noted, the stored mappings may include values related to angle of rotation of hood (103) and positions near the windshield (101A) to which the under-hood members (105) should be deployed at different speeds. In one embodiment, a first speed range, at which the hood (103) is rotated and one or more under-hood members (105) are deployed, corresponds to a speed range from about 30 kilometers per hour (kmph) to about 60 kmph. The on-board control unit (108) retrieves the designated angle of rotation and position of the under-hood members (105) for the measured speed value from stored mappings that have previously been determined to provide a desired aerodynamic performance, for example a desired drag coefficient, for the vehicle (101).
[0097] Further, at step 605, the actuators (104) rotate the hood (103) through the determined angle, while substantially simultaneously deploying /positioning the under-hood members (105) to one or more determined positions towards the windshield (101A) based on the signals received from the on-board control unit (108). Particularly, in one embodiment, the actuators (104) deploy the one or more under-hood members (105) to a first position towards the windshield (101A) when measured speed of the vehicle (101) exceeds one of the pre-set speed values.
[0098] Subsequently, at step 606, the on-board control unit (108) is configured to measure one or more aerodynamic performance parameters corresponding to the vehicle (101) subsequent to one or more of the rotation of the hood and deployment of the under-hood members as feedback. If the desired value of the aerodynamic performance parameters is achieved, the control moves to step 603, where the method continues to operate the hood assembly (100) in the last known mode while the speed of the vehicle (101) and/or value of aerodynamic performance parameters remains within a desired range.
[0099] However, if the desired value of the aerodynamic performance parameters not achieved, at step 607, the on-board control unit (108) configures the actuators (104) to further iteratively adjust the positions of one or more of the hood (103) and the under-hood members (105). Specifically, the positions of one or more of the hood (103) and the under-hood members (105) may be continually re-adjusted until the desired value of the one or more aerodynamic performance parameters corresponding to the vehicle (101) is achieved.
[0100] In one implementation, the stored mappings specify a rotation of about 10 degrees of the hood when the vehicle (101) is traveling at a speed of about 60 kmph. For a particular type of the vehicle (101), the 10-degree hood may result in approximately 30 % reduction in frontal resistance area of the vehicle (101), which in turn, may reduce the total aerodynamic drag by approximately 25 %.
[0101] It is to be understood that a person skilled in the art could design and develop a hood assembly of many similar configurations without deviating from the scope of the present disclosure. Particularly, various modifications and variations may be made without departing from the scope of the present disclosure. Therefore, it is intended that the present disclosure covers such modifications and variations that fall within the ambit of the appended claims and their equivalents.

ADVANTAGES:

[0102] The present disclosure provides a hood assembly for reducing aerodynamic drag on a vehicle and to improve aerodynamic characteristics of the vehicle. The hood assembly uses vehicle speed as input to rotate the hood to different angular positions and deploy the under-hood members to different positions towards the windshield. Particularly, the rotation of the hood to one or more angular positions and deployment of the under-hood members renders the outer profile of the vehicle closer to an ideal aerodynamic shape. Hence, the disclosed arrangement of hood assembly helps in achieving a highly aerodynamic airflow that allows the vehicle to provide optimized performance. Use of the present hood assembly also avoids the disturbing ‘wake’ along with reduction of down-force or aerodynamic drag, for a near ideal aerodynamic performance of the vehicle. The improved aerodynamic performance, in turn, provides considerable savings in fuel at every stage of vehicle propulsion.
[0103] The present disclosure provides a hood assembly for a vehicle in which the hood and the under-hood members can be manufactured/fabricated using lightweight materials, for example, carbon fibers, plastics, composites, light metals and metal alloys. Hence, presence of under-hood members underneath the hood will not impose extra weight on the vehicle. Also, the hood manufactured using above said materials may reduce overall weight of the vehicle.
[0104] Moreover, the present disclosure provides a hood assembly for a vehicle in which rotation of hood and deployment of the under-hood members is controlled electronically by an on-board control unit through one or more actuators. Since electronic based control system is interfaced, the accuracy of angle of rotation of hood and deployment of under-hood members towards the windshield corresponding to varying speeds of the vehicle is very high.
[0105] The present disclosure also provides a hood assembly for a vehicle, which has greater flexibility with respect to rotation of hood and deployability of under-hood members. The hood remains closed and under-hood members are hid under the hood when vehicle speed is lesser than predetermined speed or when vehicle is at rest. Also, the hood rotation and under-hood member deployment can be inhibited based on weather conditions and whenever wiper is to be actuated to clean the windshield. Further, the hood can be returned to a default position and under-hood members can be retracted whenever a decrease in speed of the vehicle is identified or detected by the control unit. Furthermore, the hood assembly, as disclosed herein, also improves safety and aesthetics of the vehicle by provision of under-hood members that are positioned below the hood to improve aerodynamic performance without creating any protrusions from the contour of the vehicle. In one embodiment, the hood and/or under-hood members may be deployed to improve the aesthetics of the car leading to customer satisfaction. Improving the aesthetics of the car, for example, may entail reducing the frontal area of the vehicle, as when the hood is deployed. Alternatively, improving the aesthetics of the car, for example, may entail positioning the hood assembly so as to adapt/modify the shape of the vehicle to match an airfoil shape.
[0106] Although, the present description refers to the under-hood members (105) positioned on the underside of the hood (103), in certain embodiments, the under-hood members (105) may alternatively or additionally be disposed above the surface of the hood (103). In such embodiments, these under-hood members (105) may be deployed to conceal the gap between the rotated hood (103) and the windshield (101A) in the same manner as discussed herein above.

EQUIVALENTS

[0107] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0108] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.).In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
[0109] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.