PART OF A BRAKE SYSTEM

TECHNICAL FIELD The present disclosure relates to a cooling apparatus, an assembly including a cooling apparatus and a brake system, a vehicle, and a method of cooling a part of a brake system.

BACKGROUND Certain brake systems experience an increase in temperature during use. For example, friction brake systems act to convert kinetic energy to thermal energy. Consequently, the friction brake discs in a friction brake system necessarily increase in temperature in order to function correctly. However, when a heat limit of a brake system is reached, a phenomenon known as "brake fade" may occur wherein the brake system ceases to operate optimally. Furthermore, certain metallurgical changes may take place at elevated temperatures which may lead to performance or even structural problems in the brake system.

One solution for managing thermal increases in friction brake systems is to increase the mass and hence the thermal capacity of friction brake discs. However, doing so increases manufacturing costs, adds weight to the vehicle carrying the brake system, adds unsprung mass to the system and increases noise levels, amongst other disadvantages.

In other known systems, heat management is achieved without increasing mass. An example of which is a driven air system in which a fan is provided to drive air over a hot part of the brake system such as a friction brake disc. However, the presence of a fan may restrict air flow at high vehicle speeds thereby impeding the cooling effect that might be otherwise achieved with a natural intake of air if no fan were present. Additionally, fan-based systems are unsuitable for use in environments where particulate matter such as dust, mud, water, snow, and road debris may potentially damage the fan. This is particularly problematic in off road environments. In addition, cooling systems comprising moving parts, such as fan- based systems, require periodic maintenance to ensure correct fault-free operation, increasing the vehicle's operating costs.

It is an object of the invention to provide a cooling apparatus for a vehicle brake system that mitigates for at least some of the problems of the prior art. Aspects and embodiments of the invention provide a cooling apparatus for a brake system, an assembly including the cooling apparatus and a brake system, a vehicle including the assembly, a vehicle comprising the cooling apparatus, and a method of cooling a part of a brake system of a vehicle as claimed in the appended claims.

According to an aspect of the present invention, there is provided a cooling apparatus for a brake system, comprising a duct having a first inlet, an outlet, a second inlet disposed between the first inlet and the outlet, and deflection means arranged proximate to the second inlet, wherein the deflection means is configurable to deflect a flow of air received through the second inlet towards the outlet, and to create an area of low pressure in the duct that causes air to be drawn into the duct through the first inlet towards the outlet, and wherein the outlet is configurable to be arranged proximate to a part of a brake system such that air passing out of the outlet cools the part of the brake system. The cooling apparatus advantageously provides an increased air flow towards the part of the brake system. This is in contrast with prior art arrangements in which only relative movement between a duct and the surrounding air is used to provide a cooling flow of air. As such, the cooling apparatus is capable of providing effective cooling to the part of the brake system irrespective of the speed of the duct (e.g. when installed in a vehicle) relative to the surrounding air. The cooling apparatus is therefore useful in providing a cooling effect to the part of the brake system when the speed of the duct relative to the surrounding air is low, i.e. when the natural relative airflow would be incapable of providing sufficient cooling.

The deflection means may comprise a deflector, in which case the deflector is arranged proximate to the second inlet, and is configurable to deflect a flow of air received through the second inlet towards the outlet, and to create an area of low pressure in the duct.

The deflection means may be configured to primarily direct air received through the second inlet along an inner surface of the duct. The pressure of the area of low pressure may be reduced further by directing a flow of air along the inner surface of the duct, thereby increasing the flow rate of induced air through the first inlet.

In certain embodiments, the deflection means may have an aerofoil profile.

The deflection means may include a narrowed restriction through which air passes. Such an arrangement increases the velocity of the air passing through the restriction, thus increasing the flow rate of air along the inner surface of the duct, which increases the flow rate of induced air through the first inlet.

The cooling apparatus may be operable in an active operating state or a passive operating state, and wherein in the active operating state air is actively introduced into the second inlet, and in the passive operating state air is not actively introduced into the second inlet. The cooling apparatus may be operated in the active operating state to provide forced cooling when the natural relative airflow passing through the vent is incapable of providing sufficient cooling to the part of the brake system. In contrast, the cooling apparatus may be operated in the passive operating state when forced cooling is not required or desired, e.g. if sufficient cooling may be provided by the natural relative airflow passing through the vent due to the speed of the vent relative to the surrounding air mass.

The cooling apparatus may comprise control means, for example a controller, for selectively determining whether the cooling apparatus is operating in the active operating state or the passive operating state. The cooling apparatus may comprise a sensing means, for example a sensor, communicably coupled to the control means, wherein the control means selectively determines the operating state of the cooling apparatus in dependence on data received from the sensing means. The sensing means may be configured to determine one or more of a speed of a vehicle in which the apparatus is installed, an inclination angle of the vehicle, a temperature of a part of the brake system, whether the brake system is in use, or whether a user actuated override function has been actuated. As such, appropriate data can be obtained by the sensing means and used to determine the most suitable operating state of the cooling apparatus.

The cooling apparatus may comprise air flow means for introducing air into the second inlet. The air flow means may comprise an air moving apparatus.

The cooling apparatus may comprise cooling means for cooling air introduced into the second inlet. The cooling means may comprise an air cooling apparatus configured to cool air introduced into the second inlet. The cooling effect provided by the cooling apparatus on the part of the brake system may be enhanced further by introducing cooled air into the second inlet, as this reduces the temperature of the air flow through the outlet. According to another aspect of the invention, there is provided an assembly including the cooling apparatus described above and a brake system, wherein the outlet is arranged proximate to a part of the brake system such that air passing out of the outlet cools the part of the brake system. The part of the brake system may include a friction brake disc.

According to another aspect of the invention, there is provided a vehicle including the assembly described above. The first inlet of the cooling apparatus included in the assembly may be arranged proximate to a front of the vehicle.

According to another aspect of the invention, there is provided a vehicle comprising the cooling system described above.

According to another aspect of the invention, there is provided a method of cooling a part of a brake system of a vehicle using a duct comprising a first inlet and a second inlet, the method comprising: creating an area of low pressure in the duct by passing air into the duct through the second inlet; inducing air through the first inlet and directed towards the part of the brake system due to the area of low pressure created in the duct; and cooling the part of the brake system using the air directed towards the part of the brake system. The method advantageously provides an increased air flow towards the part of the brake system. This is in contrast with prior art arrangements in which only relative movement between a duct and the surrounding air is used to provide a cooling flow of air. As such, the method is capable of providing effective cooling to the part of the brake system irrespective of the speed of the duct (e.g. when installed in a vehicle) relative to the surrounding air. The method is therefore useful in providing a cooling effect to the part of the brake system when the speed of the duct relative to the surrounding air is low, i.e. when the natural relative airflow would be incapable of providing sufficient cooling.

The method of may comprise using deflection means to deflect air passing into the duct through the second inlet. Deflecting air passing into the duct through the second inlet may comprise directing air received through the second inlet along an inner surface of the duct. In certain embodiments, the deflection means may have an aerofoil profile. In certain embodiments, the deflection means may include a narrowed restriction through which air passes.

The method may comprise determining when air is passed into the duct through the second inlet on the basis of data generated by a sensing means. For example, the sensing means may relate to a sensor. In certain embodiments a control means (e.g. a controller) may be used to determine when air is passed into the duct through the second inlet on the basis of data generated by the sensing means (e.g. the sensor). In certain embodiments the sensing means may comprise one or more sensors communicably coupled to the control means (e.g. the controller).

The method may comprise determining any one or more of: an inclination angle of the vehicle; a temperature of a part of the brake system; whether the brake system is in use; and whether a user actuated override function has been actuated. In certain embodiments, the sensing means (e.g. a sensor) may be used to determine any one or more of: the inclination angle of the vehicle; the temperature of the part of the brake system; whether the brake system is in use; and whether the user actuated override function has been actuated.

The method may comprise determining a speed of the vehicle, and actively passing air into the duct through the second inlet when the determined speed of the vehicle is below a predetermined threshold speed. For example, the speed of the vehicle may be determined using the sensing means (e.g. the sensor).

As such, appropriate data can be obtained by the sensing means and used to determine when air should be passed into the duct through the second inlet.

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 is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, 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 figures, in which:

Figure 1 shows a cross sectional side view of a cooling apparatus in accordance with an embodiment of the present invention; Figure 2A shows a detailed cross sectional side view of a part of the cooling apparatus of Figure 1 ;

Figures 2B, 2C, and 2D show detailed cross sectional side views of alternative configurations of the part of the cooling apparatus shown in Figure 2A;

Figure 3 shows a cross sectional perspective view of the cooling apparatus of Figure 1 ;

Figure 4 shows a perspective view of a vehicle comprising one or more cooling apparatuses in accordance with an embodiment of the present invention;

Figure 5 is a schematic illustration of an assembly comprising a cooling apparatus, in accordance with an embodiment of the present invention; and Figure 6 is a process flow chart outlining a method of controlling a cooling apparatus, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION Figure 1 shows a cross sectional side view of a cooling apparatus 10 in accordance with an embodiment of the present invention. In the non-limiting embodiment shown in Figure 1 , the cooling apparatus 10 is arranged to cool a part of a brake system 32. In alternative embodiments, the cooling apparatus 10 may be used to cool other components, including other components of a vehicle (not shown).

The cooling apparatus 10 comprises a duct 12 providing a conduit through which air may flow. The duct 12 has a first inlet 14 for allowing air to enter the duct 12. The duct 12 also has an outlet 18 for permitting air to exit the duct. Additionally, the duct 12 has a second inlet 16 disposed between the first inlet 14 and the outlet 18. The second inlet 16 also permits the introduction of air into the duct 12. Deflection means in the form of a deflector 20 are arranged close to the second inlet 16 such that air introduced through the second inlet 16 is deflected by the deflector 20 on its passage into the duct 12. Air entering the second inlet 16 is indicated by arrow 22 in Figure 1 and, downstream of this, air deflected by the deflector 20 is indicated by arrow 24. The deflector 20 deflects air received through the second inlet 16 towards the outlet 18. Furthermore, as a result of the Coanda effect, the deflected air flow 24 is attracted to an inner surface 12a of the duct 12, and follows a path substantially along the inner surface 12a of the duct 12. As a result of the path of this deflected air flow 24, a region 26 of low pressure is created within the duct 12, which induces a flow of air through the first inlet 14 as indicated by arrow 28. The induced flow of air 28 and the deflected flow of air 24 combine to produce an outward flow of air, indicated by arrow 30, that exits the duct 12 through the outlet 18. In the embodiment shown in Figure 1 , the outlet 18 of the air cooling apparatus 10 is arranged proximate to a part of a brake system 32, such that the outward flow of air 30 is directed to the part of the brake system 32 and provides a cooling effect by absorbing heat from the part of the brake system 32. The outward flow of air 30 may additionally induce a flow of air from around the outside of the duct 12 towards the brake system 32 thereby enhancing the cooling effect further.

In certain embodiments, the part of the brake system 32 may comprise a friction brake disc or any component of a brake system that may require cooling. In certain embodiments, the cooling apparatus 10 may be configured such that the outward flow of air 30 cools one or more parts of the brake system that may require cooling.

Figure 2A shows a detailed cross sectional side view of a part of the cooling apparatus 10 of Figure 1 that includes the deflector 20 and the second inlet 16. In the illustrated embodiment, the deflector 20 comprises a cavity 36 having a front end 36a and a rear end 36b. The cavity 36 is fluidly connected to the second inlet 16 via an inlet tube 34 that is positioned between the front end 36a and the rear end 36b. The cavity 36 comprises a cavity outlet 38 towards the rear end 36b that is defined by an opposing pair of surfaces 40a, 40b. The surfaces 40a, 40b are configured to gradually taper towards one another to form a narrowed restriction, and provide a funnel-like shape to the outlet 38. Air passing through the restriction is accelerated as a result of the tapered profile of the outlet 38, increasing the velocity of the deflected air flow 24.

The flow of air 22 entering the second inlet 16 passes along the inlet tube 34 into the cavity 36. Within the cavity 36, the flow of air follows multiple paths as indicated by arrows 23. In particular, the air flows in both a forward direction (i.e. towards the front end 36a of the cavity 36) and a rearward direction (i.e. towards the rear end 36b of the cavity) within the cavity 36. The air is deflected within the cavity 36 until it passes through the outlet 38 as deflected air 24. In the specific embodiment illustrated in the Figure 2A, the deflector 20 is configured such that deflected air flow 24 is directed along the inner surface 12a of the duct 12 towards the outlet 18. As a result of the Coanda effect, the deflected air flow 24 follows substantially the profile of the inner surface 12a even as the inner surface profile 12a curves away from the initial direction of the air flow 24, the initial direction being the direction of the air flow 24 upon exiting the outlet 38. By causing the deflected air 24 to travel along (or close to) the inner surface 12a, a deeper low pressure region 26 is created within the duct, which increases the flow rate of induced airflow 28 through the first inlet 14. In this regard it will be appreciated that the deflector 20 extends around the internal circumference of the cooling apparatus 10, as more clearly illustrated in Figure 3, and so the deflected air 24 is a circumferential flow of deflected air.

Figures 2B, 2C, and 2D show detailed cross sectional side views of alternative configurations of the part of the cooling apparatus shown in Figure 2A, that may be utilised in certain embodiments of the present invention.

In the configuration illustrated in Figure 2B, a blocker 42 is disposed within the cavity 36 axially forwardly of the inlet tube 34 towards the front end 36a of the cavity 36. The blocker 42 may relate to any component configured to inhibit airflow in a part of the cavity 36. In effect, the blocker 42 reduces the size and/or manipulates the shape of the cavity 36 that is available to the airflow 23. In certain embodiments, the blocker 42 may be a filler material that is disposed in the cavity 36. The volume of the cavity 36 available to the airflow 23 in the arrangement of Figure 2B is reduced relative to the arrangement of Figure 2A. The use of the blocker 42 may allow for a design having an optimally sized and/or shaped cavity 36 that does not compromise the form or length of the inner surface 12a of the duct 12 along which the deflected air 24 flows.

Figure 2C shows a further alternative configuration where a blocker 142 is disposed within the cavity 36 and configured to extend from the front end 36a to the rear end 36b. In this configuration the volume of the cavity 36 available to the airflow 23 is reduced relative to the configuration illustrated in Figure 2B.

Figure 2D shows a further alternative configuration where a blocker 242 is disposed within the cavity 36 and is also configured to extend from the front end 36a to the rear end 36b. The volume of the cavity 36 available to the airflow 23 in the configuration of Figure 2D is reduced relative to the configuration of Figure 2C.

Use of a blocker to reduce the volume of the cavity 36 available to the airflow 23 reduces the ability of the airflow 23 to re-circulate within the cavity 36. That is, the degree of turbulence (e.g. eddies) within the cavity 36 may be reduced. A reduction of re-circulation within the cavity 36 gives rise to a more constant mass flow rate of air passing through the outlet 38. This improves the efficiency and/or effectiveness of the cooling apparatus 10 in cooling the part of the brake system 32. In certain embodiments, the blocker may have any suitable shape or size within the cavity 36 to achieve a desired airflow therein. In alternative embodiments, the cavity 36 may be configured with the required shape or size to achieve the desired airflow both within the cavity and along the inner surface 12a of the duct 12, and the blocker may be dispensed with. Indeed, any suitable means or formation may be utilised in embodiments of the present invention to achieve an optimal (e.g. substantially constant) mass flow rate of air passing through the outlet 38. Figure 3 shows a cross sectional perspective view of the cooling apparatus 10 of Figure 1 in which it can be seen that the deflector 20 extends circumferentially around the inner surface 12a of the duct 12. In the illustrated embodiment, a single second inlet 16 is provided. However, in other embodiments, two or more second inlets 16 may be provided that are each fluidly connected to the cavity 36 and may or may not include an inlet tube 34.

In certain embodiments, the creation of the low pressure region 26 by the deflected air 24 may be described by the Venturi effect. Furthermore, and as mentioned previously, the deflector 20 may be configured to exploit the Coanda effect in order to cause the deflected flow of air 24 to travel along the inner surface 12a of the duct 12. In certain embodiments, the deflector 20 may have an aerodynamic or aerofoil profile or configuration such as the one depicted in Figure 3 for optimally achieving the Coanda effect. In other embodiments, the deflector 20 may have any alternative configuration that is capable of producing a flow of deflected air 24 that causes a region of low pressure 26 in the duct 12 irrespective of whether this is achieved by exploiting the Venturi and/or Coanda effect.

Figure 4 shows a vehicle 100 that includes one or more cooling apparatuses 10 according to an aspect of the present invention. The first inlet 14 of any one or more of the cooling apparatuses 10 may be positioned so as to receive air passing through a vent 102 located at the front 104 of the vehicle 100. In alternative embodiments, the vent 102 may be located elsewhere on the vehicle 100. In further alternative embodiments, the first inlet 14 may receive air that is not first passing through a vent.

The cooling apparatus 10 acts as a mass flow amplifier, that, in certain embodiments, may be capable of inducing up to around ten times as much air 28 per unit time through the first inlet 14 compared to the air 22 introduced through the second inlet 16. By creating an area of low pressure 26 (relative to the pressure of air mass surrounding the duct 12) the rate of airflow 28 passing into the duct 12 is increased relative to prior art arrangements in which the airflow is proportional to the speed of the vehicle.

In certain embodiments a fan, pump or other air moving apparatus or air flow means may be provided for introducing air through the second inlet 16. The air 22 introduced into the second inlet 16 may be cooled by cooling means comprising an air cooling apparatus so as to further enhance the cooling effect provided by the cooling apparatus 10. In certain embodiments, the cooling apparatus 10 may be thermally coupled to an air conditioning unit of the vehicle 100 or any other component that is capable of cooling the air 22 introduced into the second inlet 16.

The cooling apparatus 10 may be selectively operable in an active operating state or a passive operating state. In the active operating state, the flow of air 22 is actively introduced into the second inlet 16, which results in air being induced through the first inlet 14 and "forced cooling" of the brake system 32 (or other component) occurs. In the passive operating state, air may be allowed to naturally enter the duct 12 through either or both of the first inlet 14 and second inlet 16, and exits the outlet 18 to "passively cool" the brake system 32 (or other component). Thus, in the passive state, "passive cooling" may be in operation. For example, in "passive cooling" applications, the airflow 28 in the duct, and the outward flow 30 of air, may be dependent on the relative motion between the vehicle and the surrounding air mass. In certain embodiments, in the passive state, no air may enter the second inlet 16, and further, the second inlet 16 may be closed so as to prevent the introduction of air therethrough. It will be appreciated that when passive cooling is reliant on the speed of the vehicle 100 to provide a flow of air into the duct, it is less effective at low vehicle speeds. In certain embodiments, the cooling apparatus 10 may be further operable in an inactive state in which air flow is prevented from passing through the first inlet 14. For example, the first inlet 14 may be temporarily blocked (e.g. by a moveable cover) to prevent air flow therethrough. In the inactive state, air flow may or may not be permitted to pass through the second inlet 16. Preventing any air flow from passing through the first inlet 14 may, in certain circumstances, reduce vehicle drag.

Figure 5 is a schematic illustration of an assembly comprising the cooling apparatus 10, a brake system 32, control means 108 and sensing means 106. The control means 108 may be in the form of a controller, which may be provided for selectively determining the operating state of the cooling apparatus 10. The sensing means 106 may be in the form of one or more sensors communicably coupled to the control means 108. The sensing means 106 may be configured to determine one or more of: a speed of the vehicle 100, an inclination angle of the vehicle, a temperature of a part of the brake system, whether or not the brake system is in use, or whether or not a user actuated override action has been actuated. The control means 108 may selectively determine the operating state of the cooling apparatus 10 in response to data received from the sensing means 106.

The sensing means 106 and/or control means 108 may be separate to the cooling apparatus 10 and may instead be part of an assembly that includes the cooling apparatus 10, as shown in Figure 5. Alternatively, the cooling apparatus 10 may be an apparatus that includes the sensing means 106 and control means 108. It is to be appreciated that Figure 5 is a functional diagram, and any one or more of the sensing means 106, the control means 108 and the cooling apparatus 10 may be formed integrally (i.e. they may be formed together in the same hardware apparatus).

In alternative embodiments, the assembly may comprise the cooling apparatus 10 in combination with one or more of: the sensing means 106, the control means 108 and the brake system 32.

Figure 6 is a process flow chart outlining a control method 200 according to an embodiment of the present invention, for selectively operating the cooling apparatus 10. The method may be initiated at vehicle start-up. At step 202, it is determined as to whether the vehicle speed is below a predetermined threshold speed. The predetermined threshold speed may be selected to be the speed at which passive cooling becomes ineffective at adequately cooling the brake system 32. If the vehicle speed is determined to be above the predetermined threshold speed, the passive cooling mode of operation is selected, at step 208. If the vehicle speed is determined to be below the predetermined threshold speed, then it is subsequently determined, at step 204, whether a predetermined condition is met. Any one or more predetermined conditions may be considered, at step 204, where the predetermined conditions are indicative of a scenario in which forced cooling may be beneficial. The control means 108 may be configured to determine whether or not the predetermined condition is met based on information provided by the sensing means 106. If a predetermined condition is determined to be met at step 204, then the active state mode of operation is selected to provide forced cooling, subject to a "disable mode" of operation not having been previously activated, which overrides the active state mode of operation. The activation of the disable mode of operation is determined at step 205 and is discussed in further detail below. Similarly, if it is determined that the predetermined condition is not met, at step 204, then the passive mode of operation is selected, at step 208. In certain embodiments, the predetermined condition may relate to the temperature of a part of the brake system 32 (e.g. the temperature of the brake disc) exceeding a predetermined temperature threshold. For example, if the vehicle 100 has been travelling at low speed, but has experienced repeated vehicle decelerations in a short period of time, this may result in elevated brake disc temperature. This scenario may occur for example, in a low speed alpine descent or when the vehicle is parked or is travelling at low speeds following a journey involving repeated braking (e.g. on a race track). If it is determined that the predetermined temperature threshold has been exceeded, then the active state mode of operation of the cooling apparatus 10 is selected (subject to the disable mode of operation not being active), and forced cooling of the brake system, and specifically forced cooling of the brake disc may occur. The temperature of the part of the brake system 32 may be measured directly (e.g. with a thermocouple), measured indirectly, or calculated or estimated using algorithms known in the art. In certain embodiments, forced cooling (and therefore the active mode of operation) may be used to pre-emptively cool the brake system 32 to avoid it becoming too hot. In such embodiments, the predetermined condition may relate to the brake system 32 being used a predetermined number of times, or for a predetermined length of time over a predetermined time period. Therefore, whilst the temperature of the brake system 32 may not be particularly high, the cooling apparatus 10 may be operated in the active mode of operation to provide forced cooling so as to pre-emptively cool the brake system 32 to avoid it becoming too hot. Use of the brake system may be determined on the basis of the sensing means 106, which may relate to a brake sensor. Similarly, use of the brake system may be determined on the basis of the control means 108, which may relate to a control system (e.g. a controller) operatively coupled to the brake system.

The predetermined condition may comprise determination of the frequency or duration of use of the brake system 32 in combination with the determination of an angle of inclination of the vehicle 100 being greater than a predetermined threshold angle. For example, if the vehicle is travelling slowly down a steep incline and the brake system is repeatedly engaged to decelerate, the active mode of operation of the cooling apparatus 10 may be activated to provide forced cooling of the brake system 32. In such scenarios it may be beneficial to provide forced cooling, using the cooling apparatus 10, to prevent overheating of the brake system 32.

In certain embodiments, the predetermined condition may relate to the determination of an angle of inclination of the vehicle 100 being greater than a predetermined threshold angle independently from any other conditions. The sensing means 106 may include any suitable means for determining the angle of inclination of the vehicle 100, including, but not limited to, GPS and/or one or more accelerometers. In certain embodiments, the predetermined condition may relate to the actuation of a user actuated override function. For example, the user actuated override function may cause forced cooling irrespective of other factors including brake system 32 temperature, vehicle inclination, and brake system 32 use. The override function may be realised as a "Track Mode" function in certain embodiments, which may be actuated by the pressing of a button by the vehicle user (e.g. the driver).

As noted above, the predetermined condition of step 204 may encompass multiple different criteria either individually or in combination. For example, and as previously mentioned the predetermined condition may be met when the brake temperature exceeds a particular value and the inclination of the vehicle exceeds a particular angle.

If the predetermined condition is not met, and irrespective of the specific details of the predetermined condition, passive cooling is operated, at step 208. In certain scenarios, forced cooling may be undesirable. For example, in scenarios where particles and debris (such as sand, snow, mud, etc.) are likely to be drawn into the duct 12, and would be directed towards the brake system 32, forced cooling may be undesirable, since the potentially negative repercussions of blowing such particles and/or debris on the brake system 32 outweigh the benefits of cooling the brake system 32. In certain embodiments, therefore, the ability of the cooling apparatus 10 to operate in the active state may be automatically inhibited if such adverse environmental conditions are detected by the sensing means 106, or if the disable mode (e.g. an "Off Road Mode") is activated by the user. In other embodiments, the disable mode of operation may not be present. In such embodiments, the control method may be substantially similar to the control method illustrated in Figure 6, with the exception that step 205 is omitted. Therefore, activation of the forced cooling mode of operation is dependent on vehicle speed (e.g. step 202 of Figure 6) and whether the predetermined condition (e.g. step 204 of Figure 6) is met.

Embodiments of the present invention provide improved cooling apparatus, suitable for providing cooling to a brake system 32. In certain embodiments, the cooling apparatus may be selectively controlled to provide optimum cooling, whereby the forced cooling mode of operation may be implemented when brake system cooling is required, and the relative motion between the vehicle and the air mass surrounding the vehicle is insufficient to generate a sufficiently large passive airflow through the duct to satisfy the cooling requirements of the brake system 32. For example, when the relative motion between the vehicle and the air mass surrounding the vehicle, as determined on the basis of the vehicle's speed is insufficient to generate a sufficiently large passive airflow, then the forced cooling mode of operation may be implemented. Similarly, where the vehicle speed is sufficient to generate a large passive airflow, then the passive cooling mode of operation may be implemented for cooling the brake system 32. In both circumstances, the vehicle speed may be used to determine whether to implement the passive or active mode of operation.

It will be appreciated that embodiments of the present invention may be realised in the form of hardware, software or a combination of hardware and software. Any such software may be stored within volatile or non-volatile storage media such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape. It will be appreciated that the storage devices and storage media are embodiments of machine- readable storage that are suitable for storing a program or programs that, when executed, implement embodiments of the present invention. Accordingly, embodiments of the invention provide a program comprising code for implementing a system or method as hereinbefore described and/or as set out in any one of the appended claims when executed on a processor. Similarly, embodiments of the invention may relate to a machine readable storage device comprising the aforementioned program stored thereon. Furthermore, embodiments of the present invention may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or any of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments, which may not be explicitly described but which fall within the scope of the appended claims.