EP4347294A1

EP4347294A1 - Airflow apparatus for a vehicle

Info

Publication number: EP4347294A1
Application number: EP22730830.1A
Authority: EP
Inventors: Michael Farley; Nilabza DUTTA; George IORGA; Jakub KRASKA
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2021-05-27
Filing date: 2022-05-25
Publication date: 2024-04-10
Also published as: GB202107549D0; GB2607059A; WO2022248625A1; GB2607059B

Abstract

Aspects of the present invention relate to an airflow apparatus (2), control system (200) and vehicle (1). The airflow apparatus comprises: a first airflow inlet (10), (12); a first airflow outlet (14); and a second airflow outlet (16), wherein: the airflow apparatus (2) is suitable for use with a heat exchanger (18) positionable downstream of the first airflow inlet (10, 12) and upstream of the first and second airflow outlets (14, 16); the second airflow outlet (16) has a selectively variable opening (16A, 16B); and the airflow apparatus (2) is configured to control airflow downstream of the heat exchanger (18) through the first and second airflow outlets (14, 16) by selectively varying the opening of the second airflow outlet (16).

Description

AIRFLOW APPARATUS FOR A VEHICLE

TECHNICAL FIELD

The present disclosure relates to an airflow apparatus for a vehicle. In particular, but not exclusively it relates to an airflow apparatus for controlling a balance between aerodynamic performance and cooling performance.

BACKGROUND

Aerodynamics plays a key role in the design of vehicles. Particular attention is paid to the drag coefficient, as it directly affects energy consumption and therefore range and/or emissions. Some vehicles have a relatively high drag coefficient due to large areas of flow separation. Various vehicle components are accordingly designed so as to optimise the aerodynamic performance of a vehicle.

SUMMARY OF THE INVENTION

It is an aim of the present invention to provide improved control of airflow. The invention is as defined in the appended independent claims.

According to an aspect of the invention there is provided an airflow apparatus for a vehicle, the airflow apparatus comprising: a first airflow inlet; a first airflow outlet; and a second airflow outlet, wherein: the airflow apparatus is suitable for use with a heat exchanger positionable downstream of the first airflow inlet and upstream of the first and second airflow outlets; the second airflow outlet has a selectively variable opening; and the airflow apparatus is configured to control airflow downstream of the heat exchanger through the first and second airflow outlets by selectively varying the opening of the second airflow outlet. An advantage is an airflow apparatus that enables optimization of cooling performance relative to aerodynamic efficiency. This is because opening the second airflow outlet increases flow rate through the heat exchanger but is not as aerodynamically efficient as ducting airflow exclusively through the first airflow outlet.

In some examples, the airflow apparatus is also configured to selectively control airflow upstream of the heat exchanger.

In some examples, the airflow apparatus comprises an upstream variable opening device configured to be positioned upstream of the heat exchanger to selectively control airflow upstream of the heat exchanger.

In some examples, the first airflow outlet is configured to exhaust at a location of the vehicle that results in a lowering of an aerodynamic drag coefficient of the vehicle when the second airflow outlet is closed or partially closed in comparison to when the second airflow outlet is fully open, and wherein the second airflow outlet is openable to increase a flow rate of airflow through the heat exchanger.

In some examples, the location comprises a bonnet of the vehicle.

In some examples, the second airflow outlet configured to exhaust airflow at a location other than the bonnet.

In some examples, the second airflow outlet is configured to exhaust to a vented compartment of the vehicle.

In some examples, the vented compartment of the vehicle comprises an under-bonnet compartment of the vehicle.

In some examples, the airflow apparatus comprises a variable opening device to enable the selectively variable opening of the second airflow outlet, the variable opening device comprising a closed position to at least partially close the second airflow outlet, and an open position to enable airflow through the second airflow outlet. In some examples, the variable opening device for the second airflow outlet comprises air guiding elements configured to change a direction of airflow passing through the second airflow outlet.

In some examples, the variable opening device for the second airflow outlet comprises a selectable intermediate position between the open position and the closed position.

In some examples, the airflow apparatus comprises a grille, wherein the grille is shaped to define a trailing edge positioned relative to a vehicle bonnet leading edge to define an airflow opening therebetween.

In some examples, the grille comprises apertures configured to enable airflow towards the heat exchanger.

In some examples, the airflow opening of the grille is configured to direct bypass airflow bypassing the heat exchanger.

In some examples, the airflow apparatus comprises an air bypass passage configured to bypass the heat exchanger and exhaust at a vehicle bonnet opening.

According to a further aspect of the invention there is provided a control system configured to control the airflow apparatus to selectively control variable opening of the second airflow outlet, downstream of the heat exchanger, in dependence on a signal indicative of a cooling demand.

In some examples, the control system is configured to request opening of the second airflow outlet, downstream of the heat exchanger, in dependence on the signal indicating an above threshold cooling demand, and is configured to request closing of the second airflow outlet in dependence on the signal indicating a below-threshold cooling demand.

In some examples, the control system is configured to request increased airflow upstream of the heat exchanger in dependence on the signal indicating a cooling demand above a first threshold; and request opening of the second airflow outlet, downstream of the heat exchanger, in dependence on the signal indicating a cooling demand above a second threshold greater than the first threshold, to cause the second airflow outlet to be open concurrently with the increased upstream airflow.

According to a further aspect of the invention there is provided an airflow apparatus for a vehicle, the airflow apparatus comprising: a duct configured to direct airflow associated with a heat exchanger; and an outlet with a selectively variable opening located downstream of the heat exchanger.

In some examples, the duct comprises an airflow inlet, the heat exchanger, a first airflow outlet configured to exhaust airflow at a bonnet of the vehicle, and the outlet with the selectively variable opening, configured to exhaust airflow at a location other than the bonnet, wherein when the outlet with the selectively variable opening is closed, airflow can exhaust through the first airflow outlet, and when the outlet with the selectively variable opening is open, airflow can exhaust through the first airflow outlet and through the outlet with the selectively variable opening concurrently.

According to a further aspect of the invention there is provided a vehicle comprising the airflow apparatus, or the control system.

The one or more controllers may collectively comprise: at least one electronic processor having an electrical input for receiving information; and at least one electronic memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to cause the control system to cause performance of the method.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination that falls within the scope of the appended claims. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination that falls within the scope of the appended claims, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 illustrates an example of a vehicle;

FIG. 2 illustrates an example front perspective view of an airflow apparatus;

FIG. 3 illustrates an example side cross-section of an airflow apparatus;

FIG. 4 illustrates an example of an airflow apparatus in a first configuration;

FIG. 5 illustrates an example of an airflow apparatus in a second configuration;

FIG. 6 illustrates an example of an airflow apparatus in a third configuration;

FIGS. 7A-7B illustrate an example of air guiding elements in different positions;

FIG. 8 illustrates an example of a vented compartment of a vehicle;

FIGS. 9A-9B illustrate an example of upstream air guiding elements in different positions; FIG. 10 illustrates an example of an air bypass passage;

FIG. 11 illustrates an example of a system; and

FIG. 12 illustrates an example of a non-transitory computer-readable storage medium.

DETAILED DESCRIPTION

FIG. 1 illustrates an example of a vehicle 1 in which embodiments of the invention can be implemented. In some, but not necessarily all examples, the vehicle 1 is a passenger vehicle, also referred to as a passenger car or as an automobile. In other examples, embodiments of the invention can be implemented for other applications, such as commercial vehicles.

FIG. 1 is a front perspective view and illustrates a longitudinal x-axis between the front and rear of the vehicle 1 representing a centreline, an orthogonal lateral y-axis between left and right lateral sides of the vehicle 1, and a vertical z-axis. A forward direction typically faced by a driver’s seat is in the positive x-direction; rearward is -x. A rightward direction as seen from the driver’s seat is in the positive y-direction; leftward is -y. These are a first lateral direction and a second lateral direction. The vehicle 1 can comprise any appropriate torque source for delivering tractive torque to vehicle wheels 56. For example, the vehicle 1 can comprise an electric traction motor. Additionally, or alternatively, the vehicle 1 can comprise an internal combustion engine. The vehicle 1 may be an electric vehicle, a hybrid electric vehicle, an internal combustion engine vehicle, or similar.

FIG. 2 illustrates a front perspective view of a front of a vehicle 1. The vehicle 1 comprises a front bumper 66, a bonnet 22 (hood), front quarter panels 64 (fenders, front wings), wheel arches 47, and headlamp clusters 62.

The bonnet 22 is a closure panel that covers a front under-bonnet compartment 24 of the vehicle 1, irrespective of whether the under-bonnet compartment 24 comprises a torque source or not. If the torque source is provided elsewhere, then sometimes the under-bonnet compartment 24 contains other vehicle components and/or front storage (‘frunk’). The bonnet 22 may function as a lid which can be rotated opened and rotated closed, via hinges proximal to its trailing edge 35 or leading edge 34.

The terms ‘leading’ and ‘trailing’ refer to upstream and downstream locations on a vehicle 1 that is configured to primarily drive forward in the +x axis. They can also be referred to as ‘front’ and ‘rear’ edges. The trailing edge 35 of the bonnet 22 is proximal to a front glazing panel (not shown) of a cabin of the vehicle 1. The leading edge 34 of the bonnet 22 is at least a metre or more upstream of the trailing edge 35, and proximal to a top of the bumper.

Each front quarter panel 64 may cover a side section of the vehicle 1, extending downstream from the headlamp cluster 62 towards a front door. Each front quarter panel 64 extends down from a lateral edge of the bonnet 22 to the wheel arch 47 and/or to a lower sill and/or to the front bumper 66.

The front bumper 66 may be a panel covering a front section of the vehicle 1, extending up from a front lip 58, such as a front splitter, to the leading edge 34 of the bonnet 22 and/or to the headlamp clusters 62. The front bumper 66 may extend laterally to cover substantially the whole frontal width of the vehicle 1, and may comprise curved corners to extend back to the wheel arches 47 and/or to the front quarter panels 64. A pair of headlamp clusters 62 may be located to a front left corner and to a front right corner of the vehicle 1 respectively.

It would be appreciated that the above-described panels of the vehicle 1 could be implemented differently. Some panels could be merged and/or omitted.

In FIG. 2, the vehicle 1 comprises an internal heat exchanger 18 in the under-bonnet compartment 24 of the vehicle 1 behind the front bumper 66. The heat exchanger 18 is also referred to as a radiator pack. The heat exchanger 18 may comprise an air-to-liquid heat exchanger, configured to transfer heat to airflow passing therethrough. The liquid to be cooled may comprise water and/or coolant.

If the vehicle 1 is an electric vehicle, the heat exchanger 18 may comprise a radiator configured as part of a cooling system for electric vehicle components such as an electric traction battery and/or an electric traction motor.

Additionally, or alternatively, the heat exchanger 18 comprises a condenser configured as part of a cabin heating ventilation and cooling system for maintaining a user’s desired setpoint cabin temperature.

If the vehicle 1 comprises an internal combustion engine, the heat exchanger 18 may comprise an engine coolant heat exchanger.

Additionally, or alternatively, the heat exchanger 18 can comprise other types of heat exchangers such as oil coolers, intercoolers, exhaust gas coolers, etc.

The heat exchanger 18 may be configured as a log-law drag cooling system, wherein heat is conductively transferred from heat exchanger fluid to its fins and pipes which are parallel to airflow. A boundary layer of airflow along the heat exchanger fins and pipes transports heat to the airflow via convective heat transfer. The heated airflow is exhausted at an appropriate location of the vehicle 1.

As shown in FIG. 3, a fan 74 may be provided downstream of the heat exchanger 18 to actively draw air through the heat exchanger 18 when natural airflow is insufficient, for example, when the vehicle 1 is stationary. In other examples, the fan 74 is located upstream of the heat exchanger 18.

In the Figures, but not necessarily all examples, the heat exchanger 18 is tilted slightly relative to vertical. The illustrated heat exchanger 18 is tilted slightly forwards so that its top edge is further forward than its bottom edge, to optimise airflow. For substantially differently shaped vehicles, the heat exchanger 18 may be tilted differently or not at all.

In order to control airflow through the heat exchanger 18, an airflow apparatus 2 suitable for use with the heat exchanger 18 is provided within the under-bonnet compartment 24 of the vehicle 1. The airflow apparatus 2 comprises one or more first airflow inlets 10, 12 aligned with corresponding grille apertures in a central region of the front bumper 66. The central region of the front bumper 66 refers to a region laterally between the headlamp clusters 62, below the leading edge 34 of the bonnet 22, and above the front splitter 58. The airflow inlets 10, 12 may optionally have a symmetrical shape about a vehicle centreline CL.

In the Figures, but not necessarily in all examples, a first airflow inlet 10 and a second airflow inlet 12 are provided, which are fluidly connected to the same heat exchanger 18. In further examples, only one airflow inlet is provided, or more than two airflow inlets.

In some examples, one of the airflow inlets 10 is above the other airflow inlet 12, as illustrated. Therefore, the first airflow inlet 10 will be described as an upper airflow inlet, and the second airflow inlet 12 as a lower airflow inlet. In some, but not necessarily all examples, the upper airflow inlet is configured to provide airflow primarily or exclusively to an upper portion of the heat exchanger 18. In some, but not necessarily all examples, the lower airflow inlet 12 is configured to provide airflow primarily or exclusively to a lower portion of the heat exchanger 18. In other examples, the upper and lower airflow inlets 10, 12 each provide airflow to the whole heat exchanger 18 (airflow not segregated) or to different portions of the heat exchanger 18 from those given above.

The upper and lower airflow inlets 10, 12 may be vertically separated from each other by a lateral bumper member 60. In some examples, the lateral bumper member 60 covers an internal front bumper crash beam. Optionally, the lateral bumper member 60 is configured to support a vehicle licence plate when the vehicle 1 is registered. In FIG. 2, but not necessarily all examples, the upper airflow inlet 10 has a larger frontal area than the lower airflow inlet 12.

Each of the upper and lower airflow inlets 10, 12 can be covered by an individual grille 30 mounted to the front bumper 66, an example of which is shown in cross-section in FIGS. 3-6 and 9. Either the same grille 30 or different grilles 30, 31 may cover the respective upper and lower airflow inlets 10, 12. In some examples, the grilles 30, 31 may comprise a honeycomb arrangement of apertures 38 (FIG. 10), or may comprise parallel bars or any other suitable arrangement. In some examples, some of the apertures 38 in the grilles 30, 31 are blanked to control airflow, and/or in some examples, airflow may be able to enter the airflow apparatus 2 around a periphery of the grille(s) 30, 31.

The airflow apparatus 2 may comprise a duct 44 as shown by long dashed lines in FIG. 2. The duct 44 comprises the upper airflow inlet 10 and lower airflow inlet 12, wherein the upper airflow inlet 10 and lower airflow inlet 12 are aligned with corresponding grille apertures and grille(s) 30, 31 in the front bumper 66. The upper and lower airflow inlets 10, 12 may be secured to an interior side of the front bumper 66 and/or the duct 44 may be secured to various mounts within the vehicle 1. For example, the upper and lower airflow inlets 10, 12 may seal against the interior side of the front bumper 66 via a rubber seal or any other appropriate sealer, with or without additional fixings. Airflow may be guided to the heat exchanger 18 by the duct 44. The duct 44 may be a molded component such as a molded polymeric housing, for example.

In some examples, the duct 44 segregates airflows from the upper airflow inlet 10 and from the lower airflow inlet 12 and then merges the airflows in a chamber just upstream of the heat exchanger 18. This merging allows the airflows to mix when entering the heat exchanger 18. This arrangement also allows for efficient use of the airflow inlets 10 & 12, opening only one inlet at a time or progressively both in tandem to meet the cooling airflow demand in the most drag efficient manner.

If multiple heat exchanger circuits are provided, such as a radiator circuit and a condenser circuit, the airflows from the upper and lower airflow inlets 10, 12 reaching each heat exchanger circuit may be mixed rather than segregated. In other examples, the first airflow inlet 10 and the second airflow inlet 12 are separate and fluidly connected to different heat exchanger circuits. The duct 44 also extends downstream of the heat exchanger 18, as the same or a separate connected molded part. After the heat exchanger 18, the airflow may be able to mix within a downstream chamber of the duct 44 just downstream of the heat exchanger 18. The airflow then travels to airflow outlets to be exhausted. For instance, the airflow can travel to the duct extensions 45 and then exhaust through the first airflow outlet 14, and can exhaust through the second airflow outlet 16. In other examples, the airflow downstream of the heat exchanger 18 may optionally be segregated all the way from the heat exchanger 18 to respective airflow outlets.

As shown in the Figures, the duct 44 comprises one or more airflow outlets 14, 16 downstream of the heat exchanger 18, at least one of which has a selectively variable opening as shown in FIGS. 3-6. In the illustrated examples, but not necessarily all examples, the duct 44 comprises a plurality of airflow outlets 14, 16, a subset of which have a selectively variable opening.

FIG. 2 illustrates a first airflow outlet 14 and FIG. 3 additionally illustrates a second airflow outlet 16. The first airflow outlet 14 is configured to exhaust airflow through an aperture 23 in an exterior surface body panel of the vehicle 1 to define a surface airflow outlet. In some examples, the first airflow outlet 14 is covered by a grille. The second airflow outlet 16 is an interior airflow outlet configured to exhaust airflow to a volume within an interior of the vehicle 1.

The first airflow outlet 14 is configured to exhaust at a location of the vehicle 1 that has been selected (e.g., via computational fluid dynamics simulations and/or wind tunnel experiments) to lower or minimise an aerodynamic drag coefficient of the vehicle 1 when the second airflow outlet 16 is closed/partially closed in comparison to when the second airflow outlet 16 is fully open. This is because when the second airflow outlet 16 is closed, more airflow is forced to pass through the first airflow outlet 14 to the efficient exhaust location. In FIG. 2, the location is the bonnet 22.

The warm air exhausted over the bonnet 22 reduces the aerodynamic drag coefficient for several reasons, not limited to:

- better attachment of the exterior airflow structure over the bonnet 22 and exterior of the vehicle 1; - non-disruptive merging of airflow streams not leading to any separation; and

- injecting thermal energy into the airflow stream to utilize the Meredith effect.

In other examples, the first airflow outlet 14 may exhaust to a different location such as a wheel arch 47, underfloor 24 or further upstream or downstream within the bonnet 22. The location selection of this airflow outlet is influenced by several factors like packaging and also the overall drag pressure development over the length of the vehicle 1.

In some, but not necessarily all examples, an arrangement of one or more first airflow outlets 14A, 14B is provided, such as the pair of first airflow outlets 14A, 14B illustrated in FIG. 2. The pair of first airflow outlets 14A, 14B exhaust to opposite lateral sides of the centreline CL of the vehicle 1. In other examples, a single first airflow outlet 14 is provided, such as a lateral slot.

The duct 44 may comprise a duct extension 45 leading to the or each first airflow outlet 14A, 14B. The angles of the duct extensions 45 and the shapes of the first airflow outlets 14A, 14B are configured to control the direction in which airflow is exhausted.

In some, but not necessarily all examples, the first airflow outlet 14 of the duct 44 unsecuredly seals against the underside of the bonnet 22, in alignment with the corresponding bonnet aperture 23. For example, the illustrated duct extension 45 may unsecuredly seal against the bonnet 22. The seal may be provided by a rubber seal or any other appropriate non-adhesive sealer. This arrangement enables the bonnet 22 to be raised and lowered without the weight and interference considerations of having the duct 44 secured to the bonnet 22. In other examples, a portion of the duct 44 is secured to the underside of the bonnet 22 and can disengage from the rest of the duct 44 when the bonnet 22 is raised.

The duct extension 45 and/or the shape of a first airflow outlet 14 can be configured to direct the exhausting airflow downstream (-x) and upwardly relative to a bonnet-parallel orientation. The effect of exhausting airflow upwardly over the bonnet 22 is as described earlier, for reducing the aerodynamic drag coefficient. The direction of exhausting airflow is illustrated by streamlines S in FIG. 2. In the illustrated example, the duct extension 45 is oriented approximately diagonally upwardly (+z) with increasing -x distance. Optionally, the duct extension 45 and/or the shape of the first airflow outlet 14 can be configured to direct the exhausting airflow outboard, away from the centreline CL, as well as upwardly. This is further illustrated by the streamlines S in FIG. 2. An effect of directing the exhausting airflow outboard is reducing aerodynamic drag for at least some vehicle body designs. In the illustrated example, the duct extension 45 is oriented approximately diagonally outboard (y) with increasing -x distance.

The illustrated bonnet aperture 23 for the first airflow outlet 14 has an elongated shape, longer than it is narrow. The bonnet aperture 23 is longer in the x-axis than its width in the y-axis. A leading end of the bonnet aperture 23 may optionally be more inboard than a trailing end of the first airflow outlet 14, so that exhausting airflow is directed outboard.

In a conventional vehicle with bonnet vents, the bonnet vents may be open to an under-bonnet compartment of the vehicle such as an engine bay, to reduce engine bay heat. However, in examples of the present disclosure, the heat exchanger exhaust airflow is ducted all or substantially all of the way to the first and second airflow outlets 14, 16 at the bonnet 22. This enables airflow to be captured close to a stagnation point on the front bumper 66, and ducted in a manner that minimises the aerodynamic drag coefficient rather than circulating within the engine bay which can disrupt underbody/wheel arch airflow.

It is most practicable to find packaging space for the duct extensions 45 when the vehicle 1 does not comprise a bulky torque source in the under-bonnet compartment 24.

FIG. 2 also illustrates optional brake duct inlets 54, disposed outboard of the airflow inlets 10, 12, proximal to front corners of the front bumper 66. The brake duct inlets 54 may be fluidly connected to the wheel arches 47 by brake ducts 52 (FIG. 8). The brake ducts 52 may be oriented to exhaust airflow within the wheel arches 47 towards friction brakes, to passively cool the friction brakes and counteract brake fade. The brake ducts 52 may be separate from the duct 44 for the heat exchanger 18. The brake duct inlets 54 may be separate from the upper and lower airflow inlets 10, 12 for the heat exchanger 18. The brake duct inlets 54 may be at a low position on the front bumper 66 below tops of the wheel arches 47.

In some, but not necessarily all examples, the brake ducts 52 have a selectively variable opening as shown in FIG. 8. A brake duct variable opening device 53, such as a controllable valve or louvres, may be configured to control flow through the brake ducts 52. FIG. 3 schematically illustrates a side view cross-section of a vehicle 1 such as the vehicle 1 shown in FIGS. 1 and 2. The airflow apparatus 2 is visible, with the heat exchanger 18 located downstream (+x) of the upper and lower airflow inlets 10, 12, and upstream (+x) and below (- z) the first airflow outlet 14. The airflow apparatus 2 further comprises a second airflow outlet 16, downstream of the heat exchanger 18 and positioned lower than (-z) the first airflow outlet 14. The second airflow outlet 16 may be positioned below the duct extensions 45 and/or below the tops of the wheel arches 47.

The second airflow outlet 16 is configured to exhaust to a different location of the vehicle 1 than the first airflow outlet 14. In the illustrated example, the second airflow outlet 16 is configured to exhaust to a different location of the vehicle 1 than the bonnet 22. In some, but not necessarily all examples, the second airflow outlet 16 is configured to exhaust to the under bonnet compartment 24 of the vehicle 1, an example of which is shown schematically in FIG. 8, in plan view cross-section.

In some examples, the second airflow outlet 16 comprises one or more openings in the surface of the duct 44, opening to the under-bonnet compartment 24. For example, the duct 44 may be molded with said openings. In other examples, the second airflow outlet 16 exhausts to a different low-pressure vented compartment within the vehicle 1 or exhausts directly to a low- pressure exterior region of the vehicle 1.

In the following examples, the second airflow outlet 16 has a selectively variable opening. As shown in FIG. 3, the airflow apparatus 2 may comprise a downstream variable opening device 26 configured to control the second airflow outlet 16 downstream of the heat exchanger 18. The downstream variable opening device 26 may comprise a valve, louvres, or any other appropriate shutter configured to control the second airflow outlet 16. FIGS. 7A-8 later illustrate an example structure of the downstream variable opening device 26.

Additionally, or alternatively, the first airflow outlet 14 has a selectively variable opening that is controllable independently of, or in dependence on, the second airflow outlet 16. This is not shown in the Figures. In some, but not necessarily all examples, the airflow apparatus 2 further comprises an upstream variable opening device 20, as shown in FIG. 3, configured to be positioned upstream of the heat exchanger 18 to control airflow to the heat exchanger 18.

The upstream variable opening device 20 illustrated in FIGS. 3-6 is configured to control the lower airflow inlet 12 upstream of the heat exchanger 18. The upstream variable opening device 20 may comprise a valve, louvres, or any other appropriate shutter configured to control the second airflow outlet 16. FIGS. 9A-9B later illustrate an example implementation of the upstream variable opening device 20.

Additionally, or alternatively, another upstream variable opening device 72 (FIG. 10) is configured to control the upper airflow inlet 10 upstream of the heat exchanger 18. This upstream variable opening device 72 of the upper airflow inlet 10 may be a separate device from the upstream variable opening device 20 of the lower airflow inlet 12, controllable independently of, or in dependence on, the lower airflow inlet 12. Alternatively, a same upstream variable opening device may control airflow through both the upper and lower airflow inlets 10, 12.

When the downstream variable opening device 26 is in a closed position, as shown in FIGS. 3-5 and 7A, the second airflow outlet 16 is at least partially blinded. In some examples, the second airflow outlet 16 is substantially blinded, but not necessarily fully sealed unless required by the implementation.

When the downstream variable opening device 26 is in a closed position, a substantial part of the airflow from the heat exchanger 18 is exhausted through the first airflow outlet 14 which remains open. This configuration is efficient for minimising the aerodynamic drag coefficient of the vehicle 1.

When the downstream variable opening device 26 is in an open position, as shown in FIGS. 6, 7B and 8, the first airflow outlet 14 and the second airflow outlet 16 may be open concurrently, so the second airflow outlet 16 represents an additional airflow outlet. This increases total cooling airflow capacity. Therefore, opening the second airflow outlet 16 increases total cooling performance by allowing a greater rate of airflow through the heat exchanger 18. The second airflow outlet 16 exhausts to the under-bonnet compartment 24 which enables a high flow rate due to a lower pressure differential across the heat exchanger 18, and obviates a requirement for more ducting because the duct 44 is already within the under-bonnet compartment 24. However, exhausting to the under-bonnet compartment 24 is not as aerodynamically efficient as exhausting airflow substantially exclusively through the first airflow outlet 14. Therefore, the decision whether to open or close the second airflow outlet 16 represents a compromise between cooling performance and aerodynamic efficiency.

In the illustrated examples, air is able to flow through the heat exchanger 18 regardless of whether the downstream variable opening device 26 is open or closed. Therefore, the provision of a downstream variable opening device 26, rather than just an upstream variable opening device 20, means that the aerodynamic benefits of the first airflow outlet 14 can be realised even when the heat exchanger 18 is not in use (e.g., thermostat closed/coolant pump off).

When the heat exchanger 18 has achieved a sufficient cooling effect, the downstream variable opening device 26 can be closed.

In some, but not necessarily all examples, one or more of the variable opening devices mentioned above can be actuated into one or more selectable intermediate positions between the open position and the closed position. In some examples, there are five or more intermediate positions. Intermediate positions enables a controller 201 (FIG. 11) to optimise the balance between cooling performance and aerodynamic performance.

The upstream variable opening device 20, when closed, can further improve the aerodynamic drag coefficient of the vehicle 1 when cooling airflow is not required, compared to when the upstream variable opening device 20 is open.

In the illustrated examples of FIGS. 3 to 6, one of the lower and upper airflow inlets 10, 12 is always open while the other has a selectively variable opening. In this example, but not necessarily all examples, the lower airflow inlet 12 has a selectively variable opening. Leaving one airflow inlet (and outlet) always open ensures that if one or more variable opening devices become inoperative, cooling is not compromised. Table 1 below indicates how a plurality of airflow inlets 10, 12 and airflow outlets having selectively variable openings may be controlled by a controller 201 (FIG. 11), for different cooling demands by the heat exchanger 18. Some vehicles may be equipped with more, or fewer, variable opening inlets/outlets than those shown in Table 1.

FIG. 4 illustrates the positions of the upstream and downstream variable opening devices 20, 26 of FIG. 3 in cooling situations 1-3 of Table 1. FIG. 5 illustrates their positions in cooling situation 4. FIG. 6 illustrates their positions in cooling situations 5-7.

As set out in Table 1 and shown in FIGS. 4-6, a threshold cooling demand for opening an airflow inlet such as the lower airflow inlet 12 may be lower than a threshold cooling demand for opening an airflow outlet such as the second airflow outlet 16. Therefore, the lower (or upper) airflow inlet upstream of the heat exchanger 18 opens before the second airflow outlet 16 downstream of the heat exchanger 18. This is because opening outlet 16 vents all the cooling airflow into the under-bonnet compartment 24, taking all the energy out of the airflow stream thus resulting in a higher cooling system aerodynamic drag.

When the second airflow outlet 16 is opened, both the lower airflow inlet 12 and the second airflow outlet 16 are open concurrently. In the illustrated example, all the airflow inlets 10, 12 and all the airflow outlets are open concurrently in this situation.

In the static and low speed situations 2 and 7 in Table 1 , the fan 74 may be running. Aerodynamic drag may not be important but the optional strategy shown in Table 1 may provide the path of least resistance for airflow.

If at least some variable opening devices have intermediate positions, then the behaviour of such devices may be stepped or substantially continuous rather than the binary behaviour in Table 1.

It is also noted that the cooling situations can be defined differently than that shown in Table 1. A controller map may utilise threshold cooling demands or similar. A cooling demand can be based on temperature. A cooling demand can be dependent on other factors too, such as system pressure, vehicle speed, fan demand, driving mode (on-road/off-road, etc).

FIGS. 7A-7B schematically illustrate in plan view an example implementation of the downstream variable opening device 26 for the second airflow outlet 16.

In FIGS. 7A-7B, but not necessarily all examples, an arrangement of one or more second airflow outlets 16A, 16B is provided, such as the pair of second airflow outlets 16A, 16B shown in FIGS. 7A-7B. The pair of second airflow outlets 16A, 16B may be disposed to opposite lateral sides of the centreline CL of the vehicle 1. In other examples, a single second airflow outlet 16 is provided.

In this example, the downstream variable opening device 26 comprises a plurality of air guiding elements 28 such as louvres. Louvres require minimal packaging space compared to a single larger flap. The air guiding elements 28 may be deployable between a closed position shown in FIG. 7A and an open position shown in FIG. 7B.

In some examples, the air guiding elements 28 are configured to change a direction of airflow passing through the second airflow outlet 16. They may function as turning vanes. In some examples, the air guiding elements 28 are rotatable. The air guiding elements 28 are moved by any appropriate linkage connected to an actuator (not shown).

When closed, the air guiding elements 28 may be rotated into an orientation that is approximately parallel with the surrounding surface of the duct 44, to blind the second airflow outlet 16. When open, the air guiding elements 28 may be rotated to a maximum opening angle of, for example, up to 75 degrees (value between 40 and less than 90 degrees), creating slots therebetween through which air can pass. Intermediate positions, if available, can for example correspond to at least one intermediate opening angle within the range 10-20 degrees, and at least one other intermediate opening angle within the range 20-40 degrees.

The air guiding elements 28 may comprise an opening angle that is configured to change a direction of airflow passing through the second airflow outlet 16 to direct the exhausted airflow towards an opening in the under-bonnet compartment 24, to help air vent out of the under bonnet compartment 24 faster. FIG. 8 provides an example.

FIG. 8 is a plan view schematically illustrating the under-bonnet compartment 24 downstream of the air guiding elements 28 of FIG. 7B. A bottom boundary of the under-bonnet compartment 24 is defined by a vehicle body undertray 50. In some examples, the vehicle body undertray 50 is free from apertures to ensure clean underbody airflow. A top boundary of the under bonnet compartment 24 may be defined by the bonnet 22. Lateral boundaries of the under bonnet compartment 24 may be defined by wheel arch liners 46 and optionally by body panels around the wheel arches 47. It would be appreciated that the under-bonnet compartment 24 could comprise various internal equipment that is not shown.

The wheel arch liner 46 may comprise a suspension link aperture 48 enabling a suspension link (not shown) to pass from the wheel arch 47 to an inboard suspension mount. The suspension link aperture 48 provides a possible venting location for any air within the under bonnet compartment 24 to the wheel arch 47. The wheel arch 47 represents a low-pressure zone for helping to continuously exhaust air out of the under-bonnet compartment 24. In order to promote quick exhausting of air out of the under-bonnet compartment 24 and thereby maintain a useful low pressure in the under-bonnet compartment 24, the airflow guiding elements 28 of the second airflow outlet 16 of the duct 44 may be rotatable about a vertical axis to one or more opening angles that point substantially towards the suspension link aperture 48.

Where a pair of second airflow outlets 16A, 16B is provided, the airflow guiding elements 28 of a left hand one of the second airflow outlets 16A may comprise an opening angle pointing substantially towards a left suspension link aperture 48 of a left wheel arch liner 46, and the airflow guiding elements 28 of a right hand one of the second airflow outlets 16B may point substantially towards a right suspension link aperture 48 of a right wheel arch liner 46.

In other examples, the under-bonnet compartment 24 could be vented at another boundary such as the vehicle body undertray 50.

FIGS. 9A-9B are a side view schematically illustrating example air guiding elements 70 for the upstream variable opening device 20 for controlling the lower airflow inlet 12. The upstream variable opening device 20 is illustrated internally within the duct 44, downstream of the grille(s) 30, 31 and the lower airflow inlet 12. The grilles 31 may be non-actuatable. Alternatively, the upstream variable opening device 20 can be implemented as active grille shutters of the grille 31.

In this example, the upstream variable opening device 20 comprises a plurality of air guiding elements 70 such as louvres. Louvres require minimal packaging space compared to a single larger flap.

The air guiding elements 70 of the upstream variable opening device 20 may be deployable between a closed position shown in FIG. 9A and an open position shown in FIG. 9B. In some examples, the air guiding elements 70 are rotatable. The air guiding elements 70 are moved by any appropriate linkage to an actuator (not shown).

FIG. 10 illustrates a further optional aerodynamic feature of the vehicle 1 , comprising an air bypass passage 40 configured to bypass the heat exchanger 18 and exhaust airflow at an airflow outlet separate from the first and second airflow outlets 14, 16. In FIG. 10, but not necessarily all examples, the air bypass passage 40 is configured to exhaust airflow at a vehicle bonnet opening 42 at the bonnet 22. The vehicle bonnet opening 42 may comprise a lateral slot extending across the bonnet 22, for example, or a series of apertures.

The vehicle bonnet opening 42 may be located upstream of the first airflow outlet 14. The air bypass passage 40 and the vehicle bonnet opening 42 can be configured to provide an aerodynamic drag reduction by reducing eddy or separation losses. The air bypass passage 40 can capture airflow close to a leading stagnation point on the front bumper 66 and turn the airflow into an orientation that is more parallel to the bonnet 22. This functionality is similar to that already provided by the duct 44 and the first airflow outlet 14. The air bypass passage 40 provides some aerodynamic drag reduction regardless of whether airflow is possible through the duct 44. For instance, if some or all of the duct 44 can be selectively closed (e.g., the upper airflow inlet 10 also comprises its own upstream variable opening device 72), the air bypass passage 40 may continue to passively provide some aerodynamic benefit. The device 72 may optionally be the same type as the device 70.

In some examples, the air bypass passage 40 has a smaller flow capacity (e.g., average cross- sectional area) than the duct 44 for the heat exchanger 18. For example, the air bypass passage 40 can be thin in a height dimension to prevent a bonnet bulge. In examples where the air bypass passage 40 has a sufficiently large flow capacity, staggered opening of the upstream variable opening devices 70, 72 for increased cooling demand may be a possible addition to the control logic of Table 1.

In FIG. 10, but not necessarily in all examples, the grille 30 for at least the upper airflow inlet 10 does not abut the leading edge 34 of the bonnet 22. Instead, the grille 30 may be shaped to define an upper trailing edge 32, which is positioned close to, but not abutting the leading edge 34 of the bonnet 22. The grille 30 may have a curved-back shape as shown in FIG. 10, for example. The upper trailing edge 32 of the grille 30 may be substantially parallel to the leading edge 34 of the bonnet 22. This separation results in an airflow opening 36 (e.g., slit) between the upper trailing edge 32 of the grille 30 and the leading edge 34 of the bonnet 22, for providing airflow to the air bypass passage 40. Therefore, airflow passing through the apertures 38 in the grille 30 is directed through the heat exchanger 18, whereas airflow passing over the periphery of the grille 30 is directed through the air bypass passage 40.

FIG. 11 illustrates an example system 20. The system 20 comprises a control system 200 having one or more controllers 201. The control system 200 is configured to receive a signal indicative of a cooling demand from a requestor 212 such a controller or human-machine interface. The request may be indicative of a demand for cooling a component such as an electric drive unit, a traction battery, a vehicle cabin, power electronics, onboard computers, etc. The cooling demand indicates required flow through the heat exchanger 18. The system further comprises the upstream variable opening device(s) 20, 72 (if any) and the downstream variable opening device(s) 26, which comprise actuators controlled by the control system 200 in dependence on the signal indicative of the cooling demand.

In various, but not necessarily all examples, the control system 200 can be configured to:

- request opening of the second airflow outlet 16 by the downstream variable opening device 26 in dependence on the signal indicating an above-threshold cooling demand (rising threshold); and

- request closing of the second airflow outlet 16 by the downstream variable opening device 26 in dependence on the signal indicating a below-threshold cooling demand (falling threshold).

The rising and falling thresholds could be the same threshold or different thresholds for hysteresis.

- request opening of the lower and/or upper airflow inlets 10, 12 by the upstream variable opening device(s) 20, 72 in dependence on the signal indicating a cooling demand above a first threshold; and

- request opening of the second airflow outlet 16 by the downstream variable opening device 26 in dependence on the signal indicating a cooling demand above a second threshold greater than the first threshold, to cause the second airflow outlet 16 to be open concurrently with the upper airflow inlet 10. This logic of opening the inlet first is described in Table 1. As cooling demand falls, the second airflow outlet 16 may optionally be closed before the airflow inlets 10, 12 are closed. In various, but not necessarily all examples, the control system 200 can be configured to control the brake duct variable opening device 53 as indicated in Table 1. A signal indicating brake cooling demand may be different from the signal indicating cooling demand through the heat exchanger 18.

The controller 201 of FIG. 11 includes at least one processor 204; and at least one memory device 206 electrically coupled to the electronic processor and having instructions 208 (e.g. a computer program) stored therein, the at least one memory device 206 and the instructions 208 configured to, with the at least one processor 204, cause any one or more of the methods described herein to be performed. The processor may have an interface such as an electrical input/output I/O 202 or electrical input for receiving information and interacting with external components.

FIG. 12 illustrates a non-transitory computer-readable storage medium 300 comprising the instructions 208 (computer software).

For purposes of this disclosure, it is to be understood that the controller(s) described herein can each comprise a control unit or computational device having one or more electronic processors. A vehicle 1 and/or a system thereof may comprise a single control unit or electronic controller or alternatively different functions of the controller(s) may be embodied in, or hosted in, different control units or controllers. A set of instructions could be provided which, when executed, cause said controller(s) or control unit(s) to implement the control techniques described herein (including the described method(s)). The set of instructions may be embedded in one or more electronic processors, or alternatively, the set of instructions could be provided as software to be executed by one or more electronic processor(s). For example, a first controller may be implemented in software run on one or more electronic processors, and one or more other controllers may also be implemented in software run on one or more electronic processors, optionally the same one or more processors as the first controller. It will be appreciated, however, that other arrangements are also useful, and therefore, the present disclosure is not intended to be limited to any particular arrangement. In any event, the set of instructions described above may be embedded in a computer- readable storage medium (e.g., a non-transitory computer-readable storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors/computational device, including, without limitation: a magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; or electrical or other types of medium for storing such information/instructions.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. For example, the airflow apparatus 2 may comprise fewer than two airflow outlets, the sole airflow outlet having a selectively variable opening, to achieve some of the effects described herein.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. Airflow apparatus for a vehicle, the airflow apparatus comprising: a first airflow inlet; a first airflow outlet configured to exhaust at a bonnet of the vehicle; and a second airflow outlet configured to exhaust airflow at a location other than the bonnet, wherein: the airflow apparatus is suitable for use with a heat exchanger positionable downstream of the first airflow inlet and upstream of the first and second airflow outlets; the second airflow outlet has a selectively variable opening; and the airflow apparatus is configured to control airflow downstream of the heat exchanger through the first and second airflow outlets by selectively varying the opening of the second airflow outlet.

2. The airflow apparatus of claim 1, wherein the airflow apparatus is also configured to selectively control airflow upstream of the heat exchanger.

3. The airflow apparatus of claim 2, comprising an upstream variable opening device configured to be positioned upstream of the heat exchanger to selectively control airflow upstream of the heat exchanger.

4. The airflow apparatus of claim 1 , 2 or 3, wherein the first airflow outlet is configured to exhaust in an upward and downstream direction such that it results in a lowering of an aerodynamic drag coefficient of the vehicle when the second airflow outlet is closed or partially closed in comparison to when the second airflow outlet is fully open, and wherein the second airflow outlet is openable to increase a flow rate of airflow through the heat exchanger.

5. The airflow apparatus of any preceding claim, wherein the second airflow outlet is configured to exhaust to a vented compartment of the vehicle.

6. The airflow apparatus of claim 5, wherein the vented compartment of the vehicle comprises an under-bonnet compartment of the vehicle.

7. The airflow apparatus of any preceding claim, comprising a variable opening device to enable the selectively variable opening of the second airflow outlet, the variable opening device comprising a closed position to at least partially close the second airflow outlet, and an open position to enable airflow through the second airflow outlet.

8. The airflow apparatus of claim 7, wherein the variable opening device for the second airflow outlet comprises air guiding elements configured to change a direction of airflow passing through the second airflow outlet.

9. The airflow apparatus of claim 7 or 8, wherein the variable opening device for the second airflow outlet comprises a selectable intermediate position between the open position and the closed position.

10. The airflow apparatus of any preceding claim, comprising a grille, wherein the grille is shaped to define a trailing edge positioned relative to a vehicle bonnet leading edge to define an airflow opening therebetween.

11. The airflow apparatus of claim 10, wherein the grille comprises apertures configured to enable airflow towards the heat exchanger.

12. The airflow apparatus of claim 10 or 11, wherein the airflow opening of the grille is configured to direct bypass airflow bypassing the heat exchanger.

13. The airflow apparatus of claim 12, comprising an air bypass passage configured to bypass the heat exchanger and exhaust at a vehicle bonnet opening.

14. A control system configured to control the airflow apparatus of any preceding claim to selectively control variable opening of the second airflow outlet, downstream of the heat exchanger, in dependence on a signal indicative of a cooling demand.

15. The control system of claim 14, configured to request opening of the second airflow outlet, downstream of the heat exchanger, in dependence on the signal indicating an above-threshold cooling demand, and is configured to request closing of the second airflow outlet in dependence on the signal indicating a below-threshold cooling demand.

16. The control system of claim 14 or 15, configured to request increased airflow upstream of the heat exchanger as claimed in claim 2 or 3 in dependence on the signal indicating a cooling demand above a first threshold; and request opening of the second airflow outlet, downstream of the heat exchanger, in dependence on the signal indicating a cooling demand above a second threshold greater than the first threshold, to cause the second airflow outlet to be open concurrently with the increased upstream airflow.

17. A vehicle comprising the airflow apparatus of any one of claims 1 to 13, or the control system of claim 14, 15 or 16.