MODIFYING AERODYNAMIC PERFORMANCE OF A VEHICLE

Abstract

A vehicle (1; 101) is provided comprising a deployable closure panel (3; 103) which, in a deployed position, closes an air inlet (5; 105) of a vehicle body so that one edge thereof aligns with one edge of the vehicle body. A method is also provided for moving the closure panel (3; 103) into one of the deployed position and a retracted position, based on the vehicle (1; 101) satisfying a criterion. A control system (50) is provided for controlling deployment of the deployable closure panel. The control system (50) is configured progressively to deploy the deployable closure panel from the retracted position to the deployed position in dependence on an operating parameter associated with the vehicle (1; 101) to increase airflow through a closed channel formed by an airflow modification device disposed transversely across a recessed channel formed in a bonnet extending towards a bonnet rear edge.

Claims

1. A vehicle comprising: a bonnet, the bonnet comprising a front edge and a rear edge, a recessed longitudinal channel being formed in said bonnet and extending from said front edge towards the rear edge, and an airflow modification device disposed transversely across the longitudinal channel for controlling airflow over the bonnet; a deployable closure panel adapted and arranged to close an air inlet disposed below a front edge of said bonnet and defined by one or more body panels when in a deployed position and to open the air inlet defined by said one or more body panels when in a retracted position, wherein the deployable closure panel has an outer surface which aligns with an outer surface of said one or more body panels when the deployable closure panel is in the deployed position to form a substantially continuous exterior surface; the vehicle comprising a control system for controlling deployment of the deployable closure panel, the control system being configured to deploy the deployable closure panel in dependence on an operating parameter associated with the vehicle, wherein the control system is configured to deploy the deployable closure panel so as to increase airflow between said airflow modification device and said bonnet into the recessed longitudinal channel.

2. (canceled)

3. A vehicle according to claim 1, wherein the outer surface of the closure panel is profiled to form a continuation of the profile of said one or more body panels when the deployable closure panel is in the deployed position.

4. A vehicle according to claim 1, wherein the deployable closure panel is arranged such that at least one edge thereof aligns with an edge of the air inlet defined by said one or more body panels when in the deployed position.

5. A vehicle according to claim 1, wherein the deployable closure panel is positioned within the body of the vehicle when in the retracted position.

6. A vehicle according to claim 5, wherein when in the retracted position the outer surface of the deployable closure panel is arranged in a face-to-face arrangement with an inner surface of at least one of said one or more body panels.

7. A vehicle according to claim 1, wherein the air inlet is a cooling air inlet for accommodating airflow to cool one or more components of the vehicle.

8. (canceled)

9. A vehicle according to claim 1, comprising a control system configured to deploy the deployable closure panel into one of the deployed position and the retracted position.

10. A vehicle according to claim 1, wherein the vehicle operating parameter is a current speed of the vehicle.

11. A vehicle according to claim 10, wherein the deployable closure panel is moved to the deployed position based on a determination that the current speed has exceeded a predetermined speed threshold; and/or the deployable closure panel is moved to the retracted position based on a determination that the current speed has fallen below a second predetermined speed threshold.

12. A vehicle according to claim 1, wherein the vehicle operating parameter is a current temperature of a vehicle component associated with the air inlet.

13. A vehicle according to claim 12, wherein the deployable closure panel is moved to the deployed position based on a determination that the current temperature has exceeded a predetermined temperature threshold; and/or the deployable closure panel is moved to the retracted configuration based on a determination that the current temperature has fallen below a second predetermined temperature threshold.

14. (canceled)

15. A method of modifying aerodynamic performance of a vehicle, the method comprising: based on a determination that an operating parameter associated with the vehicle has satisfied at least one predetermined criterion, moving a closure panel to one of a deployed position in which the closure panel is positioned to close an air inlet defined by one or more body panels, and a retracted position in which the closure panel is moved to open the air inlet; wherein an outer surface of the closure panel aligns with an outer surface of said one or more body panels when the closure panel is in the deployed position to form a substantially continuous exterior surface; the method comprising deploying the deployable closure panel in dependence on said vehicle operating parameter so as to increase airflow between an airflow modification device and a bonnet into a recessed longitudinal channel formed in said bonnet, wherein the airflow modification device is disposed transversely across the recessed longitudinal channel, said recessed longitudinal channel extending towards a rear edge of the bonnet.

16. A method according to claim 15, wherein the outer surface of the closure panel is profiled to form a continuation of the profile of said one or more body panels when the closure panel is in the deployed position.

17. A method according to claim 15, wherein the closure panel is arranged such that at least one edge thereof aligns with an edge of the air inlet defined by said one or more body panels when in the deployed position.

18. A method according to claim 15, wherein the closure panel is positioned within the body of the vehicle when in the retracted position.

19. A method according to claim 18, wherein when in the retracted position the outer surface of the deployable closure panel is arranged in a face-to-face arrangement with an inner surface of at least one of said one or more body panels.

20. (canceled)

21. A method according to claim 15, wherein the closure panel is moved to the deployed position when the operating parameter has been determined to have exceeded a predetermined threshold.

22. A method according to claim 15, wherein the operating parameter is one of a current speed of the vehicle; and/or a current temperature of a vehicle component associated with the air inlet.

23. A controller for a vehicle, configured to perform the method as claimed in claim 15.

24-26. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0039] FIG. 1a is a front perspective view of a vehicle incorporating a deployable closure panel in a retracted position in accordance with an embodiment of the present invention;

[0040] FIG. 1b is a front perspective view of the vehicle shown in FIG. 1a with the deployable closure panel in a deployed position in accordance with an embodiment of the present invention;

[0041] FIG. 2 is a schematic block diagram of a control system in accordance with an embodiment of the present invention;

[0042] FIG. 3a is a front perspective view of a vehicle incorporating a deployable closure panel in a retracted position in accordance with an embodiment of the present invention;

[0043] FIG. 3b is a front perspective view of the vehicle shown in FIG. 3a with the deployable closure panel in a deployed position in accordance with an embodiment of the present invention;

[0044] FIG. 3c is a side profile view of the vehicle shown in FIGS. 3a and 3b with the deployable closure panel in a retracted position in accordance with an embodiment of the present invention;

[0045] FIG. 3d is a side profile view of the vehicle shown in FIGS. 3a, 3b and 3c with the deployable closure panel in a deployed position in accordance with an embodiment of the present invention;

[0046] FIG. 4a is a front perspective view of a vehicle bonnet incorporating an aerofoil in accordance with an embodiment of the present invention;

[0047] FIG. 4b is a side cross-sectional view of the vehicle bonnet and aerofoil of FIG. 4a in accordance with an embodiment of the present invention;

[0048] FIG. 4c is a side cross-sectional view of the vehicle bonnet and aerofoil of FIGS. 4a and 4b in accordance with an embodiment of the present invention, showing an example of the airflow over the vehicle bonnet;

[0049] FIG. 4d is an exploded cross-sectional view of the aerofoil of FIGS. 4a, 4b and 4c in accordance with an embodiment of the present invention, showing an example of the airflow over the vehicle bonnet;

[0050] FIGS. 5a to 7b are schematic diagrams showing alternative arrangements of the aerofoil of FIGS. 4a to 4d on a vehicle bonnet; and

[0051] FIGS. 8a to 8b are side cross-sectional views of a vehicle comprising a vehicle bonnet and aerofoil of FIGS. 4a to 4d, and the deployable closure panel of FIGS. 3a to 3d, showing an example of the airflow over the vehicle bonnet.

DETAILED DESCRIPTION

[0052] A vehicle 1 comprising a deployable closure panel 3 for an air inlet 5 of the vehicle 1 is illustrated in FIGS. 1a and 1b. FIG. 1a shows the closure panel 3 positioned in a retracted position (away from the air inlet 5) and FIG. 1b shows the closure panel 3 positioned in a deployed position (so that the closure panel 3 substantially closes the air inlet 5).

[0053] In more detail, FIG. 1a shows a vehicle 1 which is an automobile having a coupe configuration. The vehicle 1 comprises a closure panel 3, an air inlet 5, a front bumper 7 and a bonnet 9. In particular, the air inlet 5 is defined by an opening in the front bumper 7 of the vehicle 1, which allows air from outside of the vehicle to be channelled towards an engine bay (not shown) of the vehicle 1. The engine bay is at least partly covered by the bonnet 9 and houses an internal combustion engine. The engine could contain an electric machine or a combination of an internal combustion engine and an electric machine. The channelling of air from outside the vehicle, via the air inlet 5 to the engine bay therefore allows, for example, a cooling of engine components housed within the engine bay. A grille 13 (often called a radiator grille due to the design and positioning of the associated air inlet 5 allowing airflow to cool a radiator housed by the engine bay) is positioned within the air inlet 5 and acts to filter unwanted objects such as leaves and stones from entering the engine bay.

[0054] The closure panel 3 is shown by a dashed line to indicate that it is hidden from view beneath the bonnet 9. In particular, the closure panel 3 is located in a retracted position within the vehicle 1, whereby it is spaced at a distance away from the air inlet 5 so that it does not interrupt airflow via the air inlet 5 to the engine bay. The closure panel 3 is sized and shaped so that it can close the air inlet 5 to inhibit, reduce or otherwise substantially prevent airflow via the air inlet 5 to the engine bay. The closure panel 3 thus comprises a continuous (uninterrupted) outer surface 11 so that air cannot pass through the closure panel 3. The outer surface 11 is front facing in the present embodiment. In this example, the opening defining the air inlet 5 is substantially elliptical. Accordingly, the closure panel 3 has a substantially elliptical shape so that the outside edges of the closure panel locate proximal to (or abut against) the inner edges of the air inlet 5 when the closure panel 3 is positioned within the air inlet 5.

[0055] FIG. 1b depicts the closure panel 3 in a deployed configuration, whereby the closure panel 3 is arranged to substantially close the air inlet 5. The closure panel 3 thereby functions as a blanking panel at least substantially to close the air inlet 5. More particularly, the closure panel 3 is constructed and arranged to fit the air inlet 5 so that its outer surface 11 is flush with at least one external surface 15 of the front bumper 7. In this manner, the outer surface 11 of the closure panel 3 substantially aligns with at least one external surface 15 of the front bumper 7 around the air inlet 5. In doing so, the closure panel 3 forms a part of the vehicle's external surface around the vehicle 1 (known as the “A-surface” of the vehicle 1), which defines the external vehicle contour. The resulting composite surface, formed by the outer surface 11 of the closure panel 3 and the at least external surface 15 of the front bumper 7, forms a substantially continuous exterior surface. The closure panel 3 in its deployed position acts to substantially redirect airflow around the front bumper 7 so that the airflow via the air inlet 5 is inhibited.

[0056] In operation, the closure panel 3 is moved between the retracted position (shown in FIG. 1a) and the deployed position (shown in FIG. 1b). Accordingly, the movement from the retracted position to the deployed position acts to modify the vehicle's A-surface and hence fluid flow in and around the vehicle 1. The closure panel 3 may be initialised (e.g. when the vehicle 1 is switched off or otherwise not running) at a default position which may either be the retracted position or the deployed position.

[0057] The operation of the closure panel 3 will now be described in more detail with reference to FIG. 2. For simplicity of explanation, the following example assumes that the default configuration is in the retracted configuration but it will be understood that the default configuration may be initialised in either of the retracted configuration or the deployed configuration.

[0058] A control system 50 is provided within the vehicle 1 for controlling deployment of the closure panel 3. The control system 50 comprises a control means 55, an actuation means and a mechanical assembly 65. The control means 55 may be a control module of a vehicle (not shown), a computer, a processing module, and so forth. As such, the control means 55 may comprise one or more processors, one or more memories and/or logic circuitry and may be capable of executing computer program code. The actuation means is in communication with the control means 55 and may be any form of actuator 60 suitable for moving the closure panel 3 into one of a deployed position and a retracted position. The actuator 60 may, for example, comprising a pneumatic piston, an hydraulic piston, an electric motor, and so forth. The mechanical assembly 65 is in communication with the actuator 60 and accommodates the deployment and retraction of the closure panel 3 in the different positions. Accordingly, the mechanical assembly 65 may comprise devices to enable the necessary rotation and/or translation of the closure panel 3.

[0059] The actuator 60 receives a control signal from the control means 55 to deploy the closure panel 3 to the deployed position. At least in certain embodiments, the control means 55 can be configured to deploy the closure panel 3 progressively to control the proportion of the air inlet 5 which is closed. Responsive to, or based on the control signal received from the control means 55, the actuator 60 causes the mechanical assembly 65 to move the closure panel 3 to the deployed position so that the closure panel 303 effectively seals or closes the air inlet 5. At any point thereafter, the actuator 60 may receive a subsequent control signal indicating that the closure panel 3 should be retracted from the air inlet 5 and accordingly instructs the mechanical assembly 65 to move the closure panel 3 to its retracted position away from the air inlet 5.

[0060] In the example of FIGS. 1a and 1b, the control system 50 for the deployment and retraction of the closure panel 3 is dependent on the speed of the vehicle when travelling. Accordingly, the closure panel 3 is only deployed when it has been determined by the control system 50 that the vehicle 1 is travelling at a current speed that is above a predetermined speed threshold. For example, the closure panel 3 may be deployed after the vehicle 1 has been determined to exceed a predetermined speed threshold of either 30 kilometres per hour (kmph), 40 kmph, 50 kmph, 60 kmph or 70 kmph. If it is determined that the current vehicle speed has fallen below the predetermined speed threshold when the closure panel 3 is in its deployed position, the control system 50 then enables the closure panel 3 to be moved to its retracted position. It will be understood that varying levels of performance may be achieved for closure panel deployment for different vehicles at different speeds and that the predetermined speed threshold at which the closure panel should be deployed is chosen so that the relevant vehicle has improved aerodynamic efficiency at and above that speed.

[0061] In the illustrated arrangement of FIGS. 1a and 1b, the vehicle 1 is shown to have a coupe configuration, however it will be appreciated that the closure panel 3 can be used in other vehicle configurations. For example, the vehicle 1 can be an off-road vehicle or a sports utility vehicle.

[0062] FIGS. 3a to 3d show an vehicle 101 having a saloon (sedan) configuration. Like reference numerals are used to those shown in FIGS. 1a and 1b but increased by one hundred, in order to depict like elements. In this example, the air inlet 105 is associated with a front bumper skirt grille (not shown) of the vehicle 101 rather than the air inlet 5 associated with the radiator grille 13 as described with reference to FIGS. 1a and 1b. The air inlet 105 is used to channel cooling air towards vehicular components (such as those housed within the engine bay of the vehicle 101).

[0063] FIG. 3a shows a front view of the vehicle 101 having a closure panel 103 located in a retracted position. The closure panel 103 is depicted by dashed lines to show that it is hidden from view within the front bumper skirt 107 and above the air inlet 105. Consequently, in the retracted position, the air inlet 105 associated with the closure panel 103 is exposed so as to enable cooling airflow to be channelled towards the vehicular components for which the air inlet 105 is designed.

[0064] FIG. 3b shows the vehicle 101 of FIG. 3a with the closure panel 103 located in the deployed position. The closure panel 103 is sized and shaped so as to substantially close the air inlet 105 and thereby inhibit air flow via the air inlet 105 to the vehicular components. In particular, the air inlet 105 is substantially trapezoid-shaped with the greatest length on a top side of the air inlet 105 and is symmetrical about a vertical axis. The closure panel 103 therefore has the same shape as the air inlet 105 so that its outer edges are arranged to fit within the inside edges of the air inlet 105 when the closure panel 103 is in its deployed position. The closure panel 103 has a continuous front facing surface so as to prevent air from passing through the closure panel 103.

[0065] FIG. 3c shows a cross-sectional side view of the vehicle 101 having the closure panel 103 located in the retracted position so that it does not interfere with the airflow via air inlet 105. The front bumper skirt 107 of the vehicle 101 has a recessed side profile, which defines at least part of the air inlet 105. When the vehicle 101 is travelling, cooling air can be channelled via the air inlet 105 to the appropriate vehicle components.

[0066] FIG. 3d shows a cross-sectional side view of the vehicle 101 when the closure panel 103 is located in the deployed position. The closure panel 103 substantially closes the air inlet 105 so that its front facing surface 111 is flush with at least one surface edge 115 of the front bumper skirt 107. The closure of the air inlet 105 is performed so that the closure panel 103 effectively defines a portion of an outer A-surface of the vehicle 101. The resulting composite surface, formed by the front facing surface 111 of the closure panel 103 and the external surface of the front bumper skirt 107, forms a substantially continuous exterior surface of the vehicle 101.

[0067] The operation of the closure panel 103 is similar to that described above with reference to FIGS. 1a to 3. In particular, the closure panel 103 is operated so that it is moved to a deployed position after a current speed of the vehicle 101 has exceed a predetermined speed threshold and is moved to a retracted position once the current speed of the vehicle 101 has fallen below the predetermined speed threshold.

[0068] Embodiments of the present invention as described herein refer to various air inlets 5; 105, which may be opened or closed using various closure panels 3; 103 so as to modify aerodynamic efficiency. Whilst some air inlets may be specifically designed to control aerodynamic efficiency, many of the air inlets 5; 105 may be designed to enable airflow to cool one or more internal components of a vehicle and consequently may be referred to as “cooling air inlets”.

[0069] It will be appreciated that, whilst embodiments of the present invention have been described with reference to the examples described above, various modifications and alternatives will be apparent. For example, in the above examples described with reference to FIGS. 1a to 3d, the control mechanism for deployment of the closure panel 3; 103 is dependent on a current speed of the vehicle 1; 101. In other examples, such deployment may alternatively or additionally be dependent on other parameters and criteria. For example, where an air inlet 5; 15 associated with a particular closure panel 3; 103 is configured to control air flow to a heat-sensitive vehicle component such as a radiator or the brakes of the vehicle, the deployment of the closure panel 3; 103 may be temperature dependent. In such cases, it will be appreciated that these heat-sensitive components will have an optimum temperature range within which they may operate at their maximum efficiency. Accordingly, a control loop may be provided such that the closure panel 3; 103 is deployed to restrict airflow when the temperature of the relevant component is below a minimum threshold for optimum functionality (to assist heating of the relevant component), and retracted to encourage airflow when the temperature is above a maximum threshold (to assist cooling of the relevant component). Alternatively or additionally, the control mechanism may be dependent on the vehicle's mode of operation. For example, a manual operation may be performed by a user of the vehicle such that they may select an option (via a user interface of the vehicle) so as to indicate that the one or more closure panels 3; 103 should be deployed. Alternatively, the control mechanism may be dependent on a selected driving mode of the vehicle 1, such as one or more of the following: SPORT, DYNAMIC, ROAD, ECONOMY and OFF-ROAD. In some instances, a single speed and/or temperature threshold is used to signal deployment or retraction, however, in other examples, an upper threshold and lower threshold may be used for reasons of hysteresis (i.e. to prevent a current speed or temperature that fluctuates around the predetermined threshold from causing an excess of control signals to deploy and retract the closure panel).

[0070] The external surface of the vehicle 1; 101 is typically painted. The continuous outer surface 11; 111 of the closure panel 3; 103 may have a painted finish which matches, or contrasts with, the painted external surface of the vehicle 1; 101.

[0071] Although the above examples described with reference to FIGS. 1a to 3 provide examples of a single closure panel being used in association with a single air inlet, it will be appreciated that multiple closure panels may be used to cover multiple air inlets, respectively. In such a case, each closure panel may be separately controlled by the control system 50.

[0072] Embodiments of the present invention also relate to using an airflow modification device in the form of an aerofoil 201 (airfoil) to control air flow around a motor vehicle such as the motor vehicles 1; 101 depicted in FIGS. 1a, 1b and 3a to 3d.

[0073] FIG. 4a is a schematic front perspective view of a vehicle bonnet 203 having a recessed channel 205 in a longitudinal direction (in a direction along the X-axis) of a vehicle. The bonnet 203 is formed from a continuous, uninterrupted surface that extends from a front (leading) edge 207 (at a front of a vehicle) towards a rear (trailing) edge 209. The front edge 207 is proximal to a top edge of a front bumper (not shown) of the vehicle. The rear edge 209 is proximal to a windscreen (not shown) of the vehicle. The front edge 207 and the rear edge 209 of the bonnet 203 are joined by a left side edge 211 and a right side edge 213. The side edges 211, 213 are disposed proximal to top side edges (not shown) of the front bumper. The bonnet 203 acts as a cover for a vehicle engine bay such as that discussed herein with reference to FIGS. 1a to 3d. The bonnet 203 in this example has a “clamshell” configuration, whereby the front edge 207 and the left and right side edges 211, 213 of the bonnet 203 curve and extend around the vehicle to partially define the front and sides of the vehicle.

[0074] The recessed channel 205 is formed such that the recess has a maximum depth at the front edge 207 of the bonnet 203 and decreases in height extends towards the rear edge 209 of the bonnet 203. First and second side portions 215, 217 are thereby formed on either side of the channel 205.

[0075] The channel 205 comprises a guide surface 219 (i.e. the surface between the left and right side edges 211, 213). The guide surface 219 acts to direct air flow over the bonnet 203 and towards the top of the windscreen (not shown) of the vehicle as the vehicle is travelling in a forward direction. In the present embodiment the guide surface 219 is continuous and uninterrupted and is formed without air inlets or apertures.

[0076] An aerofoil 201 is disposed at the front of the bonnet 203 and extends transversely between the side portions 215, 217. More particularly, the aerofoil 201 is spaced above the guide surface 219 of the bonnet 203 at a predefined height so that there is a through-gap between the aerofoil 201 and the guide surface 219 of the bonnet 203, thereby forming a horizontal passage 221 to allow airflow through to the recessed channel 205. The aerofoil 201 is secured in position by the side portions 215, 217 via securing or fixing means (not shown). The aerofoil 201 is described in greater detail below with reference to FIG. 4d.

[0077] FIG. 4b shows a cross-sectional side view of the bonnet 203 and aerofoil 201 of FIG. 4a.

[0078] FIG. 4c is a simplified schematic diagram showing a cross-sectional side view of the aerofoil 201 and bonnet 203 of FIGS. 4a and 4b, with arrows 223 depicting fluid flow over the guide surface 219 of the bonnet 203 as the vehicle is travelling in a forward direction. The aerofoil 201 controls the airflow so that the flow of air travels through the horizontal passage 221 and along the recessed channel 205, substantially parallel to the guide surface 219 with minimal disturbance compared with the airflow if no aerofoil 201 were present. The aerofoil 201 thus acts to guide or channel the airflow over and around the top of the vehicle. At least in certain embodiments, this arrangement can improve vehicle efficiency.

[0079] FIG. 4d is a simplified schematic diagram showing a cross-sectional side view of the aerofoil 201 in further detail. The aerofoil 201 is constructed with an upper surface 225 and a lower surface 227, which upper and lower surfaces 225, 227 meet to form a leading edge 229 and a trailing edge 231. The leading edge 229 acts to channel airflow above and below the aerofoil 201 as the vehicle is travelling. In this regard, the position and angle of the aerofoil 201, and indeed the shape and dimensions of the aerofoil 201 are constructed and arranged to streamline the vehicle. It will be understood that these parameters (position, angle, shape, dimensions, etc.) of the aerofoil 201 will vary according to the design of the vehicle.

[0080] A first vertical separation distance is defined between the leading edge 229 and the guide surface 219 and a second vertical separation distance is defined between the trailing edge 231 and the guide surface 219. In the present embodiment, the lower surface 227 of the aerofoil 201 is arranged substantially parallel to the guide surface 219 such that the first and second vertical separation distances are substantially equal. In other examples, the second separation distance may be greater than the first separation distance so as to decelerate airflow over the guide surface 219. In other examples, the second separation distance may be smaller than the first separation distance so as to accelerate airflow over the guide surface 219. The aerofoil 201 and the recessed channel 205 can be viewed as forming a closed channel which is open at each end (i.e. at the front and back). In a first configuration, the closed channel can converge as it extends towards the rear of the bonnet. In a second configuration, the closed channel can diverge as it extends towards the rear of the bonnet.

[0081] In the example described above with reference to FIGS. 4a to 4b, a bonnet 203 is provided having a continuous, uninterrupted surface. In this regard, there are no air inlets or apertures provided on the bonnet 203 or at least along the guide surface 219 of the bonnet 203 such that cooling air is not provided to the engine bay through the bonnet 203. Therefore, separate flow paths are provided around the vehicle for such cooling functionality, such as via the air inlets 5; 105 described with reference to FIGS. 1a, 1b and 3a to 3d.

[0082] It will be appreciated that, whilst embodiments of the present invention have been described above with reference to FIGS. 4a to 4d, various modifications and alternatives will be apparent. For example, in the above examples described with reference to FIGS. 4a to 4d, the aerofoil 201 has a fixed structure. In other examples, the aerofoil 201 may additionally comprise moving parts. For example, the trailing edge 231 of the aerofoil 201 may comprise one or more movable flaps with an adjustable angle (with respect to a horizontal plane) to enable control of aerodynamic lift. The angle of the flaps may be dynamically adjusted dependent on a current speed of the vehicle so as to maximise the aerodynamic efficiency of the vehicle and minimise resistance to airflow over the guide surface 219 of the bonnet 203.

[0083] In the above examples described with reference to FIGS. 4a to 4d, an aerofoil 201 is used to channel airflow over the guide surface 219. However, it will be appreciated that in other examples a different element or airflow modification device may be used, having a shape other than the aerofoil 201 shown, in order to channel airflow over the guide surface 219.

[0084] It will be appreciated that the positioning of the aerofoil 201 along the bonnet 203 may vary according to characteristics and design of the relevant vehicle. FIGS. 5a to 7b illustrate examples of varying aerofoil 201 positions along the bonnet 203. In particular, FIGS. 5a and 5b show the aerofoil 201 being positioned so as to follow the contour of the side portions 215, 217 as viewed from the side of the vehicle. FIGS. 6a and 6b show the aerofoil 201 being placed to protrude beyond the front of the vehicle. FIGS. 7a and 7b show the aerofoil being set back from the front of the vehicle.

[0085] Various closure panels and aerofoils have been described herein. Such elements may be constructed using materials common to vehicle construction such as alloys, aluminium, plastics, fibreglass and other such composite materials.

[0086] FIGS. 8a and 8b illustrate airflow around a vehicle comprising both an airflow modification device 201 as described herein and at least one deployable closure panel 103 as described herein. Streamlines are depicted for purely illustrative purposes.

[0087] FIG. 8a depicts a first configuration in which two deployable closure panels 103 are in retracted positions (not shown). It may be appreciated that one or any number of deployable closure panels 103 can be used. Streamlines 801 are illustrated terminating at cooling inlet(s) to represent airflow entering the cooling inlet(s). A streamline is illustrated extending towards the underside of the vehicle 1, 101. Another streamline 803 is illustrated extending between the airflow modification device 201 and the bonnet into the recessed longitudinal channel 205, representing airflow through the recessed longitudinal channel 205.

[0088] FIG. 8b depicts a second configuration in which the deployable closure panels 103 are in their deployed positions. Reference numerals are omitted for features present in FIG. 8a. Flow that cannot enter the cooling inlet(s) is diverted around the exterior of the vehicle 1, 101. Two streamlines are illustrated extending towards the underside of the vehicle, representing increased flow towards the underside. Two streamlines 805 are illustrated extending between the airflow modification device 201 and the bonnet into the recessed longitudinal channel 205, representing increased airflow through the recessed longitudinal channel 205.

[0089] Combining the airflow modification device 201 with deployable closure panels 103 in the second deployed configuration illustrated in FIG. 8b, allows for a lower-loss flow path for the airflow excluded from the cooling inlet(s), increasing the aerodynamic drag reduction relative to the drag reduction that would be possible with deployable closure panels 103 alone.

[0090] In some, but not necessarily all examples, the control system is configured to control deployment of the deployable closure panel and vary the cross-sectional area of the closed channel formed by the airflow modification device 201 and recessed channel 205 together. The cross-sectional area of the closed channel can be varied by moving the one or more flaps described herein, or moving the airflow modification device and/or at least a portion of the bonnet. This may advantageously enable front axle lift, drag reduction and cooling inlet flow to be balanced in dependence on one or more of the operating parameters described herein.

[0091] The embodiment(s) described herein refer to a vehicle comprising two doors (excluding the tailgate or boot lid), but the vehicle could have a four door configuration (excluding the tailgate or boot). For example, the vehicle could be a saloon (sedan) or a sports utility vehicle. It will be appreciated that aspects of the present invention(s) could be applied to other vehicle configurations. For example, the vehicle could be an estate car (station wagon), hatch-back, coupe, off-road vehicle or a sports utility vehicle. Furthermore, the invention(s) described herein are not limited to motor vehicles. The vehicle can be an automobile, a truck, a lorry, an articulated vehicle and so on.

[0092] The present disclosure describes positioning adjacent panels to form a substantially continuous exterior surface. It will be appreciated that this is subject to usual manufacturing clearances and tolerances for exterior panels. A shut line (or cut line) is formed between adjacent panels where one (or both) of the panels is movable. The shut line comprises a clearance gap to accommodate relative movement of the panels. The outer surfaces of the panels on each side of the shut line are aligned with each other to form the substantially continuous exterior surface described herein. Thus, the composite exterior surface (defined by two or more panels) is substantially continuous insofar as it is free from steps or offsets at the interface between the panels. By way of example, the substantially continuous exterior surface can comprise a continuous curved surface (formed in 2-dimensions or 3-dimensions) and/or a continuous planar surface.