GB2601176A

GB2601176A - Control system for a vehicle cooling system

Info

Publication number: GB2601176A
Application number: GB2018351.3A
Authority: GB
Inventors: Dutta Nilabza; John Tickle David
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2020-11-23
Filing date: 2020-11-23
Publication date: 2022-05-25
Also published as: DE102021213190A1; GB202018351D0

Abstract

A control system (310 fig 7a) is provided for a cooling system of a vehicle, which uses a radiator 22 and an air flow directing mechanism (14, 16 fig 4) which can be put into a first position directing air via a wheel region (18 fig 2) and a second position bypassing it. The control system determines a cooling parameter in dependence on a received first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition, and then outputs a director signal in dependence on the cooling parameter, which controls the directing mechanism into the first or second position. Aspects of the invention also relate to a cooling system: a directing mechanism; a cooling fan 12; a vehicle (1 fig 1); a method (400 fig 8); computer software; and a computer-readable storage medium. The invention utilises air pressure in a wheel region and is effective at regulating radiator cooling and is applicable where there is a low temperature gradient and for example in electric vehicles and in fuel cell vehicles.

Description

CONTROL SYSTEM FOR A VEHICLE COOLING SYSTEM

TECHNICAL FIELD

The invention relates to the control of a cooling system for a vehicle. Aspects of the invention relate to a control system, a directing mechanism, a cooling fan, a cooling system, a vehicle, a method, computer software and a non-transitory computer-readable storage medium. In particular, but not exclusively the invention relates to the control of a cooling system for a fuel cell vehicle.

BACKGROUND

It is known to provide cooling for powertrain components of a vehicle by means of a radiator wherein heat transfer, or heat rejection, serviced by the radiator is determined in part by a temperature gradient across the radiator, and in part by the pressure drop of air passing across a surface of the radiator. When the temperature gradient is low a higher air pressure drop is required to service the same heat rejection. Vehicles powered by a battery or a fuel cell typically have a relatively low radiator temperature gradient compared with internal combustion engine vehicles since electrical/fuel cell powertrain components operate at lower temperatures than engines. Consequently, the heat rejection in battery and fuel cell vehicles is very dependent on air pressure drop. However, a large air pressure drop is associated with increased aerodynamic drag especially at high vehicle speeds. Furthermore it can be difficult to arrange for a large air pressure drop at low vehicle speeds, and some driving conditions require a lot of heat rejection even at low vehicle speeds.

It is an aim of the present invention to address the problems associated with the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided a control system for a cooling system of a vehicle, the control system comprising one or more controller, the cooling system comprising a radiator and a directing mechanism for directing an air flow downstream from the radiator, the directing mechanism operable in a first position and a second position, the control system configured to receive a first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition, determine a cooling parameter in dependence on the first signal and the second signal, output a director signal in dependence on the cooling parameter, for controlling the directing mechanism to be operable in the first position or the second position, wherein in the first position the directing mechanism is configured to direct air flow via a first air path to a wheel region of the vehicle, and in the second position the directing mechanism is configured to direct air flow via a second air path to bypass the wheel region.

The advantage of providing a directing mechanism for directing an air flow downstream from the radiator is that air may be directed towards a low air pressure in a region downstream of the radiator, so enabling a greater cooling air flow through the radiator independently of the air pressure upstream of the radiator. The air pressure in a wheel region may be determined by the aerodynamic features and speed of the wheel and the air pressure in a bypass region may be determined by different aerodynamic features of the vehicle, for example where the bypass region is unobstructed by the wheel and/or is subject to a venturi effect which reduces pressure. The benefits of providing control of such a directing mechanism include that the pressure drop across the radiator, and therefore the heat rejection of the radiator, may be controlled according to the operating condition of the vehicle and/or according to a cooling requirement.

According to an embodiment of the invention an air pressure in the wheel region of the first air path is lowered by a spinning road wheel fan moment. This provides the advantage that the first path may be effective at enabling an increased air flow through the radiator when the wheel is spinning at high speed, such as when the vehicle is travelling at high speed. It must be understood that in the present document a spinning wheel is a rotating wheel, which may or may not be freely spinning relative to the road surface due to poor traction. In some situations the spinning road wheel fan moment can increase the pressure drop without having recourse to the use of a cooling fan which would use energy from the vehicle energy store. It is also advantageous to be able to switch to the second air path because in some driving situations the cooling system does not require increased air flow through the radiator -for example, when the powertrain components need to be warmed. In such driving situations the second air path may be selected in order to avoid a higher pressure drop being caused by the spinning road wheel fan moment, and so avoid an increased air flow through the radiator.

In some embodiments the directing mechanism is operable in a third position and the director signal is for controlling the directing mechanism to operate in the third position wherein the third position is configured to inhibit air flow via the second air path. This provides an additional benefit of limiting the air flow in the second air path and/or of ensuring that air is directed via an air path that is not the second air path. By this means the heat rejection may be further controlled, and the cooling air flow may be increased without additional energy expenditure such as increasing drag or by means of a fan.

Additionally the directing mechanism may be operable in a fourth position and the director signal is for controlling the directing mechanism to operate in the fourth position wherein the fourth position is configured to inhibit air flow via the first air path. This provides an additional benefit of limiting the air flow in the first air path and/or of ensuring that air is directed via an air path that is not the first air path. By this means the heat rejection may be further controlled, and the cooling air flow may be increased without additional energy expenditure such as increasing drag or by means of a fan.

Some embodiments provide for the director signal controlling the directing mechanism to operate in a fifth position comprising the first and second position. The fifth position allows mixing of air flow via both the first and second air paths which can be useful in controlling the degree of heat rejection.

Some embodiments provide for the director signal controlling the directing mechanism to operate in a sixth position comprising the third and fourth position. The sixth position is used to inhibit air flow through the radiator, which may be useful for allowing the cooling system to warm rapidly, so allowing the powertrain components to warm rapidly. Powertrain components such as batteries and motors generally operate more efficiently when they are warm than when they are cold.

Optionally the vehicle operating condition comprises one or more of the following: a current vehicle speed, an anticipated vehicle speed, a vehicle acceleration, an air speed, and a wind direction. This provides the advantage that the heat rejection may be set according to the conditions under which the vehicle is operating. It may be desirable to provide greater cooling for a vehicle which is anticipated to, at some future point, be driven at high speed against a headwind, for example.

The cooling requirement may comprise a temperature of a coolant, and/or a temperature of a powertrain component, and/or a heat-flux requirement of the vehicle. This provides the advantage that the cooling system is configured according to the degree of heat rejection required by the powertrain components. This is important because powertrain components generally operate most effectively within specific temperature ranges. The efficiency of a powertrain component may be maximized at a specific temperature.

In an embodiment the second air path comprises a low air pressure region provided by a venturi effect created underneath the vehicle. The venturi effect may be generated by the relative air movement passing the moving vehicle, acting on aerodynamic forms of the second air path as the vehicle moves at speed. The venturi effect thereby creates the low air pressure region in the second air path and so may increase the air pressure drop across the radiator. Therefore the advantage of providing a venturi effect in the second air path is that cooling air flow may be increased because the low air pressure region draws air through the radiator.

This is beneficial because the heat rejection may be increased in this case, and may be more efficient than other means of increasing the pressure drop such as deploying a fan.

Alternatively, or additionally, an air pressure in the second air path is associated with a deflecting feature for deflecting the air flow to the outside of the wheel region. The advantage is that cooling air flow at the radiator is improved even by a pre-existing aerodynamic feature which may be present for other reasons. For example a deflecting feature such as an aerodynamic drag lift (ADL) lip or a deflector for directing air flow around a wheel. Such features are known to those skilled in the art, and as well as deflecting air they may also develop localised regions of low pressure which may then be included in an air path of the present invention.

In some embodiments the second air path is directed to a lateral side surface of the vehicle or to an upper surface of the vehicle. The advantage of deflecting air to a side or upper surface of the vehicle is that cooling air flow may then be different in the second air path compared to that in the first air path, so heat rejection may be controlled by selecting the path. Also by directing air to a side or upper surface there are different effects on the aerodynamic behaviour of the vehicle compared with the air being directed to underneath the vehicle or into the wheel region. The aerodynamics may impact the downforce acting on the vehicle, and so impact the vehicle handling and dynamics. This may be beneficial in different vehicles where the balance of heat rejection and vehicle dynamic requirements is different.

In an embodiment the control system receives a third signal indicative of a vehicle dynamic condition, the control system determining an aerodynamic downforce parameter in dependence on the third signal, and wherein the directing signal is determined in dependence on the downforce parameter. This provides the advantage that the vehicle dynamics may be controlled by adjusting the cooling air flow under the vehicle, and can be important for providing a good driving response for the driver of the vehicle.

The cooling system may comprise a cooling fan and the control system is configured to output a cooling fan signal in dependence on the cooling parameter, for controlling the duty of the cooling fan. The cooling fan may be positioned adjacent to the radiator or in the first air path or in the second air path. The advantage is that air flow may be increased by the fan which assists the cooling system to provide greater heat rejection. If the fan is only in one of the first or second air paths then an increase in the air resistance due to the presence of a non-rotating fan in the other air path is avoided. Having the cooling fan in only one air path can be used to enhance the heat rejection in that path alone.

The cooling fan may be an electrically powered cooling fan. Electrical power is a convenient method for powering a fan on a vehicle, and also easily configured for the control of the fan.

According to further aspects of the invention there are provided a directing mechanism, a cooling fan, a cooling system and a vehicle.

According to a still further aspect of the invention there is provided a method for controlling a cooling system of a vehicle, the cooling system comprising a radiator and a directing mechanism for directing an air flow downstream from the radiator, the directing mechanism operable in a first position and a second position, the method comprising: receiving a first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition, determining a cooling parameter in dependence on the first signal and the second signal, outputting a director signal in dependence on the cooling parameter, for controlling the directing mechanism to operate in the first position or the second position, wherein in the first position the directing mechanism is configured to permit air flow via a first air path to a wheel region of the vehicle, and in the second position the directing mechanism is configured to permit air flow via a second air path to bypass the wheel region.

The advantage of such a method is that the air flow may be configured to control heat rejection of a cooling system by directing air downstream of a radiator to a low air pressure region.

A yet further aspect of the invention provides a method for controlling a cooling system of a vehicle, the cooling system comprising: a radiator; a cooling fan; and a directing mechanism for directing an air flow downstream from the radiator, the directing mechanism operable in a first position and a second position, the method comprising: receiving a first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition, determining a cooling parameter in dependence on the first signal and the second signal, outputting a director signal in dependence on the cooling parameter, for controlling the directing mechanism to operate in the first position or the second position, outputting a cooling fan signal in dependence on the cooling parameter, for controlling the duty of the cooling fan, wherein in the first position the directing mechanism is configured to permit air flow via a first air path to a wheel region of the vehicle, and in the second position the directing mechanism is configured to permit air flow via a second air path to bypass the wheel region.

The advantage of such a method is that the air flow may be configured to control heat rejection of a cooling system by directing air downstream of a radiator to a low pressure region and by controlling the duty of a cooling fan.

An aspect of the invention provides computer software that, when executed, is arranged to perform methods as described. The advantage is that the methods may be implemented in a controller for a cooling system of a vehicle.

An aspect of the invention provides a non-transitory, computer-readable storage medium storing instructions thereon that, when executed by one or more electronic processors, causes the one or more electronic processors to carry out the methods as described. The advantage is that the methods may be implemented in a controller for a cooling system of a vehicle.

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 drawings, in which: Figure 1 is a perspective view of a vehicle according to an embodiment of the invention; Figure 2 is a plan view of the front right corner of the vehicle of Figure 1, showing a horizontal section along the line A-A' in Figure 1; Figure 3 is a side view of the front right corner of the vehicle of Figure 1, showing a cutaway portion along the line B-B' in Figure 1, to reveal elements of the cooling system and the director mechanism in the third position; Figure 4 is the same view as Figure 3 with the director mechanism in the fourth position; Figure 5 is a side view of the front right corner of the vehicle according to another embodiment of the invention and the director mechanism in the fifth position; Figure 6 is the same view as Figure 5, including a fan, and the director mechanism in the third position; Figures 7A, 7B illustrate an example of a control system and of a non-transitory computer-readable storage medium; Figure 8 provides a method for controlling a cooling system according to an embodiment of the invention; and Figure 9 provides a modified method for controlling a cooling system according to an embodiment of the invention.

DETAILED DESCRIPTION

In order to avoid overheating powertrain components such as batteries, fuel cells, power electronics, electric machines, transmissions and engines there is a need to reject heat via a radiator of a cooling system. It is known that the amount of heat rejected by a radiator is determined in part by a temperature gradient across the radiator, and in part by the pressure drop of air passing across a cooling surface of the radiator. The air pressure drop is itself determined in part by the speed of the vehicle such that at high speed a greater pressure drop is possible. In fact, as is known to persons skilled in the art, the air pressure drop depends on the speed of the vehicle relative to the speed and direction of any ambient wind. The air pressure drop across a radiator also depends in part on the aerodynamic characteristics of the vehicle at different speeds, both upstream and downstream of the radiator. The term 'upstream' is understood to mean a region in which air flows towards the radiator, with 'downstream' meaning a region in which air flows away from the radiator. Normally the upstream region will be towards the front of a vehicle when the vehicle is moving in a forward direction, and the downstream region will then be considered to be behind the radiator. Such a downstream region may be anywhere in which air flows away from the radiator, such as an engine bay, or a wheel arch, or an underneath of the vehicle, or an exhaust or transmission tunnel, or a vent enabling the air to flow to some other surface of the vehicle. For example, some radiators have a downstream vent opening onto a bonnet surface.

At some vehicle operating conditions, aerodynamic features of the vehicle can generate low air pressure which, if they are downstream of the radiator, can contribute to a large air pressure drop across the radiator. However, different aerodynamic features can develop low pressures at different operating conditions, meaning that the location of the lowest air pressure region varies with the operating condition of the vehicle. An operating condition may include the speed or acceleration of the vehicle and/or the speed and direction of the ambient air.

A large pressure drop is associated with high aerodynamic drag acting on the vehicle, meaning that energy is expended by the vehicle to force air through the radiator. This increased energy expenditure reduces the overall energy efficiency of the vehicle; that is, the energy required to make the vehicle travel a given distance. If the heat rejection requirement at a given operating condition is low then an energy expenditure due to such aerodynamic drag would be wasteful. This means that simply designing for a consistently large pressure drop across the radiator is not always desirable because in some operating conditions there is minimal requirement for heat rejection and the aerodynamic drag caused by a large pressure drop would make the vehicle less efficient than if the pressure drop were lower.

However, it is sometimes desirable for there to be a large air pressure drop across the radiator even when the vehicle speed is low. For example, when the vehicle is travelling slowly off-road with the powerunit generating a large amount of power and a substantial amount of heat is being rejected by the powertrain components. Example scenarios include driving up a steep gradient or through deep dry sand or over boulders. In this case it can be difficult to arrange for a large pressure drop since the vehicle speed is low and the pressure at the front of the vehicle is therefore low.

Therefore the designer of a cooling system for a battery or fuel-cell powered vehicle has conflicting requirements. At times there is a great demand for heat rejection at high speeds, and a large pressure drop may easily be provided. Sometimes there is a great demand for cooling capacity at low vehicle speeds. This may require a large pressure drop across the radiator but the aerodynamic features of the vehicle are not helpful for developing a large pressure drop at low speed. At other times there is low demand for cooling capacity, and a large pressure drop across the radiator would be wasteful of energy because the large pressure drop is associated with high aerodynamic drag. The present invention provides the vehicle designer with a way of controlling the air pressure drop by directing the air flow downstream of the radiator to different regions of air pressure.

A vehicle 1 according to an embodiment of the invention is shown in Figure 1. An opening 4 in the front surface of the vehicle 1 permits ambient air to enter the cooling system. In this example the opening is in the bumper 2 towards one side of the vehicle 1, but suitable openings may be provided elsewhere such as underneath the bumper 2, at the side of the vehicle 1, underneath the vehicle 1 or towards the centre of the vehicle 1. In the example shown in Figure 1 the opening 4 is in front of a road wheel 6. In this case the road wheel 6 is a front wheel although the opening may usefully be positioned in front of a rear wheel. A plan view of the arrangement is shown in Figure 2, in a sectional view through the wheel arch and vehicle road wheel 6 at A-A'. In this view the wheel 6 is seen as comprising spokes 8 connecting the hub 7 of the wheel, with the tyre 10 on the wheel rim 5.

In Figure 2 air entering the opening 4 passes through a radiator 22, the air being directed by guides 2. The guides 2 may be of any suitable form such as ducting or deflecting panels and will be known to those skilled in the art. Arrows indicate the direction of air flow as the vehicle is moving forwards, entering through the opening 4 to the inboard side of the vehicle road wheel 6 and then through spaces between the spokes to the outboard side of the wheel.

Figure 2 indicates an air pressure P1 at the front of the vehicle 1 and a lower air pressure P2 in a region 18 inboard of the vehicle road wheel 6. Due to the air pressure difference (P1-P2) air passes through the radiator 22. In an embodiment of the invention a cooling fan 12 is provided in an location behind the radiator. Other cooling fan positions may be useful.

The pressure P2 is determined in part by a spinning road wheel fan effect or moment. Spokes 8 are designed to behave like fan blades so that air is drawn between the rotating spokes 8, so that the road wheel operates as a centrifugal fan. In this situation the road wheel may be spinning because the vehicle is moving at speed, or the wheel may be spinning because it is slipping against the road surface while the vehicle is moving at low speed. For example, a known technique for driving in deep dry sand does provide for a fast-spinning wheel while the vehicle itself is moving slowly.

In the arrangement of Figure 2, air is drawn from a wheel region 18 which is inboard of a wheel 6 (i.e. towards the centreline of the vehicle), the air being drawn between the spokes to the outboard side of the wheel 6 and thereby reducing the air pressure P2 in the wheel region 18.

It should be noted that without the spinning road wheel fan effect then the air flow in the wheel region 18 will be affected by the obstructions of the chassis components 9 such as suspension links, wheel knuckle, brake calliper, and brake disc which may block the flow of air. Therefore, although the air pressure P2 in the wheel region 18 may effectively be reduced by the centrifugal fan effect of the spinning road wheel, at other times the same wheel region 18 will not have a particularly low air pressure P2 due to such obstructions, and in a given circumstance a lower air pressure may be available if the wheel region 18 is bypassed to avoid such obstructions. For example, if the wheel is not spinning and the cooling fan 12 is operating to draw air through the radiator 22, then the air pressure P2 in the wheel region 18 would not be reduced by the spinning road wheel fan effect at all, and in that case there would be less resistance to air exiting the fan if it bypassed the obstructions within the wheel region 18 altogether.

A side view of the cooling system through section B-B' is shown in detail in Figure 3, in which air entering the opening 4 passes through the radiator 22, the air being directed by the guides 2. The cooling fan 12 is also shown in Figure 3, positioned adjacent to the downstream face of the radiator. Other cooling f an 12 locations are possible and will be described later.

Figure 3 indicates the air pressure P1 at the front of the vehicle 1, and the air pressure P2 downstream of the radiator in the wheel region 18 which is towards the inboard side of the road wheel 6 of the vehicle 1. Therefore the air pressure drop across the radiator is substantially defined as (P1-P2) when the effects of friction and the cooling fan 12 are discounted.

Figure 3 illustrates a first air path downstream of the radiator 22 being opened by means of a directing mechanism operating in a first position. In Figure 3 the directing mechanism comprises a door 14 and a positioning device 16 such as a DC motor, wherein the door 14 is pivotally rotated by the positioning device 16. Methods other than a DC motor may be employed for the positioning device 16. As will be described later, the position of the directing mechanism 14, 16 in Figure 3 may also be described as the third position. In this embodiment the flow control surface of the directing mechanism is in the form of a door 14 but this function of the directing mechanism may also be performed by other devices such as louvres, vents, vanes, moving panels, deflectors or any other means known to those skilled in the art for directing air flow.

If the wheel is spinning such that the spinning road wheel fan effect reduces the pressure P2 then the door 14 of the directing mechanism may be operated in the first position to direct air flow via the first air path to the wheel region 18 as shown in Figure 3. At high vehicle speed the pressure drop (P1-P2) across the radiator is relatively large due a high air pressure P1 at the front of the vehicle and also due to the reduction in air pressure P2 caused by the spinning road wheel fan effect. A high vehicle speed driving condition may be above 50kph, and particularly above 80kph. If the wheel is spinning because there is a loss of traction with the road surface, rather than because the vehicle is travelling at high speed, then it is the rotational speed of the wheel that is relevant to determining the position of the door 14 of the directing mechanism, and so the rotational speed may be referenced as an equivalent vehicle speed or a surrogate value thereof.

Figure 4 illustrates the same embodiment as Figure 3 but shows the door 14 of the directing mechanism in a second position for directing air flow downstream of the radiator 22 via a second air path in order to bypass the wheel region 18. The condition of Figure 4 may be used when the wheel speed is low, for example if the vehicle speed is equal to or less than 80kph. A vehicle speed of less than 50kph may also be useful for defining a low speed threshold for the purposes of determining the operation of the directing mechanism. If the wheel 6 is rotating slowly such that the spinning road wheel fan effect would be negligible in reducing the pressure P2, then the directing mechanism may be operated in the second position to direct air flow via the second air path to bypass the wheel region 18 to a different low pressure region 28. In this case the pressure of air downstream of the radiator P2' may be less than the pressure P2 that would be achieved with the directing mechanism in the first position under the same vehicle operating conditions.

Advantageously the pressure drop across the radiator P1-P2' when the directing mechanism is in the second position may be greater than the pressure drop across the radiator P1-P2 when the directing mechanism is in the first position. Therefore it is the quantities P1-P2' and P1-P2 which are helpful in determining the optimum position of the directing mechanism, rather than simply P2' and P2. P2' in the bypass region 28 with the directing mechanism in the second position may be a lower pressure than P2 in the wheel region 18 with the directing mechanism in the first position because it is a shorter path to the ambient air, or because it is not obstructed by the wheel, chassis and suspension components 9, or because of other aerodynamic features that influence the air pressure in the bypass region 28. An example of such an aerodynamic feature which may influence the air pressure P2' in the bypass region 28 is shown in Figures 3 to 6 where a lip 20 is positioned underneath the vehicle in front of the wheel, sometimes called an Aerodynamic Drag Lift (ADL) lip 20. The purpose of such a feature may be to deflect air to the outside (outboard) of the wheel or to detach air flow from the underneath of the vehicle or some other purpose or combination of purposes. However, irrespective of the main purpose such a feature may also provide an area of low pressure which is suitable, in some driving conditions, for enabling the low pressure P2' in the bypass region 28.

The low pressure P2' may be generated by a venturi effect created underneath the vehicle by the form of the undersurface of the vehicle. In this case the cooling air flow via the second air path is directed to the underneath of the vehicle to bypass the wheel region.

The low pressure P2' may be associated with the air passing at the side surface (lateral aspect) of the vehicle, for example on a wing area of the vehicle. In this case the cooling air flow via the second air path is directed to the lateral side surface of the vehicle to bypass the wheel region.

The low pressure P2' may be associated with the air passing on an upper surface (top) of the vehicle, for example on or near to the bonnet area of the vehicle. In this case the cooling air flow via the second air path is directed to an upper surface of the vehicle to bypass the wheel region.

The first position is not always associated with high vehicle speed and the second position is not always associated with low vehicle speed. In some driving conditions the vehicle speed is low but the road wheel 6 is spinning fast because it is slipping against the road surface, or against the mud or sand if driving off-road. This situation may occur when the vehicle 1 is being driven in deep dry sand and the vehicle 1 is designed to make progress by spinning the wheels rapidly. This condition may be termed 1wheelspin'. In such a condition the directing mechanism might usefully be operated in the first position even though the vehicle speed is low. The cooling system may then benefit from the spinning road wheel fan effect acting to reduce the pressure P2 below what would be achieved by pressure P2' if the directing mechanism was operated in the second position.

The directing mechanism may also be operated in a third position configured to inhibit air flow in the second air path. This is also illustrated in Figure 3 where the door 14 of the directing mechanism in the first position inhibits air flow via the second air path as well as directing air flow via the first air path. Therefore, in the case of Figure 3 the directing mechanism is in both the first and the third position. The advantage of this embodiment and configuration is that a single device (door 14) may be employed to direct all the air via the first air path and none via the second air path. Other embodiments may provide the same directing effect, such as an air guide being hinged upstream to direct air flow via the first air path and not the second air path.

Conversely, the directing mechanism may also be operated in a fourth position configured to inhibit air flow in the first air path. This is also illustrated in Figure 4 where the door 14 of the directing mechanism in the second position inhibits air flow via the first air path as well as directing air flow via the second air path. Therefore, in the case of Figure 4 the directing mechanism is in both the second and the fourth position. The advantage of this configuration is that a single device (door 14) may be employed to direct all the air via the second air path and none via the first air path. As above, other arrangements may provide the same directing effect, such as an air guide being hinged upstream to direct air flow via the second air path and not the first air path.

It is possible for the door 14 of Figure 3 and 4 to be positioned to allow air to flow in both the first and second air paths at the same position. Other embodiments may better facilitate such a condition, such as that shown in Figure 5 and 6 now described.

Figures 5 and 6 illustrate yet a further embodiment of the invention using positionable louvres 30, 32 for implementing the directing mechanism instead of the door 14 and positioning device 16 of the embodiment of Figures 3 and 4. In the embodiment of Figures 5 and 6 the first and third positions and the second and fourth positions are not necessarily coupled together as they are in the embodiment of Figures 3 and 4. The embodiment of Figures 5 and 6 may then be operated in a first position but not a third position. Alternatively the embodiment of Figures 5 and 6 may then be operated in a second position but not a fourth position.

Figure 5 illustrates the embodiment operating in a fifth position wherein the first and second positions are operated simultaneously to allow air flow via both the first path and the second path. This is the condition illustrated in Figure 5, where both the louvres 30, 32 are open. This may be desirable in some intermediate conditions where the cooling effect of the air flow is to be moderated in order to limit the heat rejection of the cooling system.

The directing mechanism may also be operated in a sixth position wherein the third and fourth positions are operated simultaneously to inhibit air flow via either the first path or the second air path. This condition would arise if both the louvres 30, 32 of Figure 5 are closed. This may be desirable when the cooling effect of the air flow would be detrimental to the overall system performance, for example if the heat rejection is to be limited so that the powertrain components operate more efficiently when warmed. In such an instance the cooling requirement placed upon the cooling system of the vehicle would require that all cooling be inhibited so that the cooling system, and the powertrain components serviced by the cooling system, are warmed quickly.

Figure 6 illustrates the louvres 30, 32 operating in the second and fourth position, so that the directing mechanism is in the second position to direct air flow via the second air path and also in the fourth position to inhibit air flow via the first air path. Therefore, in terms of the position of the directing mechanism Figure 6 is the equivalent of Figure 4.

In some circumstances a low pressure area underneath the vehicle is desirable in order to assist in the dynamic control of the vehicle. In this case the low pressure can provide a downforce on the vehicle which will provide or enhance vehicle stability during cornering manoeuvres. Therefore the directing mechanism position is determined according to the vehicle dynamic condition. This is likely to be a short-term requirement and so would be unlikely to greatly impact the cooling performance.

It will be understood that a cooling fan 12 as hereinbefore described may be provided for assisting in the development of a pressure drop across the radiator 22. Positioning the cooling fan 12 in front of the radiator 22 may enhance the upstream pressure coming into the radiator 22. In this location the cooling fan may be protected by a mesh or grill to prevent damage to the cooling fan 12 by objects entering the opening 4. In alternative embodiments the cooling fan 12 is positioned downstream of the radiator 22 in order to draw air through the radiator 22.

Figures 3 to 5 illustrate a cooling fan 12 positioned adjacent to the radiator 22 for this purpose.

The cooling fan 12 may be positioned adjacent to the radiator 22 or may be positioned in either the first air path or the second air path. For example, Figure 6 shows the cooling fan 12 in only the second air path while the directing mechanism is in the second and fourth positions. In this way the cooling fan 12 assists in the movement of air in the second air path but does not provide an obstruction in the first air path. This is advantageous if the cooling system designer needs to enhance cooling air flow at low vehicle speeds, but simultaneously needs to reduce aerodynamic losses at high vehicle speeds.

The cooling fan 12 is preferably electrically powered for convenience and in order to facilitate control of the cooling fan 12.

It will be understood from the foregoing that the preferred position of the directing mechanism 14, 16, 30, 32 depends on at least the cooling requirement of the powertrain components and the vehicle operating condition. Figure 7A illustrates how a control system 310 may be implemented for determining the position of the deflecting mechanism. The control system 310 of Figure 7A illustrates a controller 300. In other examples, the control system 310 may comprise a plurality of controllers on-board and/or off-board the vehicle 1.

The controller 300 of Figure 7A includes at least one processor 302; and at least one memory device 304 electrically coupled to the electronic processor 302 and having instructions 306 (e.g. a computer program) stored therein, the at least one memory device 304 and the instructions 306 configured to, with the at least one processor 302, cause any one or more of the methods described herein to be performed. The processor 302 may have an electrical input/output 308 or electrical input for receiving information and interacting with external components.

Figure 7B illustrates a non-transitory computer-readable storage medium 312 comprising the instructions 306 (computer software). The controller 300 is thus enabled to carry out a method of controlling the directing mechanism, and an example of such a method 400 is provided in Figure 8.

According to Figure 8 an embodiment of the controller 300 is configured to receive a first signal 402 indicative of a cooling requirement of the vehicle and to also receive a second signal 404 indicative of a vehicle operating condition. The controller 300 then determines a cooling parameter 406 in dependence on the first signal 402 and the second signal 404. The cooling parameter 406 may be a series of parameters for describing the optimized condition of the cooling system and directing mechanism for servicing the cooling requirement. For example the cooling requirement may consist of a requirement to inhibit cooling so that the powertrain components are allowed to warm quickly. This may be useful for enabling the powertrain components to operate efficiently.

The contents of the steps shown in Figure 8 are listed in Table 1.

Step Description

402 Receive cooling requirement signal 404 Receive vehicle operating condition signal 406 Determine cooling parameter 408 Output director signal 410 Configure directing mechanism position In dependence on the cooling parameter(s) the control system 310 then outputs a director signal 408 for controlling the directing mechanism. The directing mechanism is thus configured to operate in one or more of the positions 410 previously described.

Figure 9 provides an example modification of Figure 8 for a method 401 incorporating the control of the fan duty. In order to control the cooling fan 12 the control system 300 is configured to output a cooling fan signal 412 in dependence on the cooling parameter. The cooling fan signal 412 may take the form of a cooling fan 12 speed signal or of a pulse-width modulation (PWM) signal or some other signal for controlling fan duty. In this way the cooling fan throughput or duty 414 is controlled, either by controlling the cooling fan 12 speed or by controlling the proportion of time that the cooling fan 12 is powered or some other means.

Tabir. ad 401 Step Descri *tion 402 Receive cooling requirement signal 404 Receive vehicle operating condition signal 406 Determine cooling parameter 408 Output director signal 410 Configure directing mechanism position 412 Determine fan duty 414 Control fan duty The vehicle operating condition may comprise one or more of the following conditions: a current vehicle speed, an anticipated vehicle speed, a vehicle acceleration, an air speed, and a wind direction. The anticipated vehicle speed may be derived from mapping data or other route data which provides an indication of the vehicle speeds that are likely to be attained on the route ahead. Such indication might be determined by satellite navigation system data, traffic data, weather data, terrain information or a combination of these. The data may be provided to a controller on the vehicle or to a controller remote from the vehicle for processing and onward communication as part of the control system 310. Data may also be derived from machine learning algorithms for anticipating a current journey on the basis of previous journeys.

The cooling requirement may comprise an indication of the heat that must be transferred through the cooling system in order to maintain or achieve the desired thermal condition of the powertrain components. Therefore the cooling requirement may be in the form of a temperature of a coolant or a temperature of a powertrain component, for example the temperature of an electric motor or fuel-cell or sub-component thereof. The cooling requirement may comprise a heat-flux requirement for the cooling system. The heat-flux requirement may be defined in terms of the amount of energy to be expelled through the cooling system in a given time period, or it may be defined as a correlate of such a metric. For example the amount of heat-flux may be determined by a look-up table in which driving conditions, such as the vehicle operating conditions or the environmental conditions, will give rise to specific levels of heat-flux to be expelled through the cooling system.

For purposes of this disclosure, it is to be understood that the controller(s) 300 described herein may each comprise a control unit or computational device having one or more electronic processors. A vehicle 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.

The blocks illustrated in Figure 8 may represent steps in a method 400 and/or sections of code in the computer program 306. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted.

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.

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

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 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 endeavouring 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 claim 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

CLAIMS1. A control system for a cooling system of a vehicle, the control system comprising one or more controller, the cooling system comprising a radiator and a directing mechanism for directing an air flow downstream from the radiator, the directing mechanism operable in a first position and a second position, the control system configured to: receive a first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition; determine a cooling parameter in dependence on the first signal and the second signal; and output a director signal in dependence on the cooling parameter, for controlling the directing mechanism to be operable in the first position or the second position, wherein in the first position the directing mechanism is configured to direct air flow via a first air path to a wheel region of the vehicle, and in the second position the directing mechanism is configured to direct air flow via a second air path to bypass the wheel region.
2. The control system according to claim 1 wherein an air pressure in the wheel region of the first air path is lowered by a spinning road wheel fan moment.
3. The control system according to any preceding claim, wherein the directing mechanism is operable in a third position and the director signal is for controlling the directing mechanism to operate in the third position wherein the third position is configured to inhibit air flow via the second air path.
4. The control system according to any preceding claim, wherein the directing mechanism is operable in a fourth position and the director signal is for controlling the directing mechanism to operate in the fourth position wherein the fourth position is configured to inhibit air flow via the first air path.
5. The control system according to any preceding claim, wherein the director signal controls the directing mechanism to operate in a fifth position comprising the first and second position.
6. The control system according to any preceding claim, wherein the director signal controls the directing mechanism to operate in a sixth position comprising the third and fourth position.
7. The control system of any preceding claim wherein the vehicle operating condition comprises one or more of the following: a current vehicle speed, an anticipated vehicle speed, a vehicle acceleration, an air speed, and a wind direction.
8. The control system of any preceding claim wherein the cooling requirement comprises a temperature of a coolant, and/or a temperature of a powertrain component, and/or a heat-flux requirement of the vehicle.
9. The control system of any preceding claim wherein the second air path comprises a low pressure region associated with a venturi effect created underneath the vehicle.
10. The control system of any preceding claim wherein an air pressure in the second air path is associated with a deflecting feature for deflecting the air flow to the outside of the wheel region.
11. The control system of any preceding claim wherein the second air path is directed to a lateral side surface of the vehicle.
12. The control system of any preceding claim wherein the second air path is directed to an upper surface of the vehicle.
13. The control system of any preceding claim wherein the control system receives a third signal indicative of a vehicle dynamic condition, the control system determining an aerodynamic downforce parameter in dependence on the third signal, and wherein the directing signal is determined in dependence on the downforce parameter.
14. The control system of any previous claim wherein the cooling system comprises a cooling fan and the control system is configured to output a cooling fan signal in dependence on the cooling parameter, for controlling the duty of the cooling fan.
15. The control system of claim 14 wherein the cooling fan is positioned adjacent to the radiator.
16. The control system of claim 14 wherein the cooling fan is positioned in the first air path or the second air path.
17. The control system of claims 14 to 16 wherein the cooling fan is an electrically powered cooling fan.
18. A directing mechanism according to any previous claim.
19. A cooling fan according to any previous claim.
20. A cooling system according to any previous claim. 15
21. A vehicle according to any previous claim.
22. A method for controlling a cooling system of a vehicle, the cooling system comprising a radiator and a directing mechanism for directing an air flow downstream from the radiator, the directing mechanism operable in a first position and a second position, the method comprising: receiving a first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition, determining a cooling parameter in dependence on the first signal and the second signal, outputting a director signal in dependence on the cooling parameter, for controlling the directing mechanism to operate in the first position or the second position, wherein in the first position the directing mechanism is configured to permit air flow via a first air path to a wheel region of the vehicle, and in the second position the directing mechanism is configured to permit air flow via a second air path to bypass the wheel region.
23. A method for controlling a cooling system of a vehicle, the cooling system comprising: a radiator; a cooling fan; and a directing mechanism for directing an air flow downstream from the radiator, the directing mechanism operable in a first position and a second position, the method comprising: receiving a first signal indicative of a cooling requirement and a second signal indicative of a vehicle operating condition, determining a cooling parameter in dependence on the first signal and the second signal, outputting a director signal in dependence on the cooling parameter, for controlling the directing mechanism to operate in the first position or the second position, outputting a cooling fan signal in dependence on the cooling parameter, for controlling the duty of the cooling fan, wherein in the first position the directing mechanism is configured to permit air flow via a first air path to a wheel region of the vehicle, and in the second position the directing mechanism is configured to permit air flow via a second air path to bypass the wheel region.
24. Computer software that, when executed, is arranged to perform a method according to claims 22 or 23.
25. A non-transitory, computer-readable storage medium storing instructions thereon that, when executed by one or more electronic processors, causes the one or more electronic processors to carry out the method of claims 22 to 23.