Active deflection system for a motor vehicle

Abstract

Motor vehicle (10, 10', 10''), comprising: a body (12) with a bottom; a plurality of vehicle wheels (14, 14') arranged on the underside, each corresponding wheel of the plurality of vehicle wheels (14, 14') having a respective contact surface for contacting a driving surface, an underbody space being defined between the contact surfaces and the underside of the body (12); a movable wind deflector (28, 28', 28'') coupled to the underside and projecting into the underbody space, the movable wind deflector (28, 28', 28'') having a first position and a second position, the first position having a first blocking profile in the underbody space and the second position having a second blocking profile in the underbody space that is different from the first blocking profile; an actuator (32, 32', 32'') coupled to the movable wind deflector (28, 28', 28'') and configured to drive the movable wind deflector (28, 28', 28'') between the first position and the second position; and a controller (34, 34', 34'') configured to control the actuator (32, 32', 32'') in response to compliance with an operating condition to move the movable wind deflector (28, 28', 28'') from the first position to the second position, wherein the movable wind deflector (28, 28', 28'') comprises an elongated element (30, 30', 30'') having a first end and a second end, the first end being coupled to the actuator (32, 32', 32''), and the actuator (32, 32', 32'') being configured to drive the elongated element (30, 30', 30'') in a pivoting movement about a pivot axis passing through the first end, wherein the movable wind deflector (28, 28', 28'') comprises a second elongate member (30, 30', 30'') coupled to the actuator (32, 32', 32''), and wherein the actuator (32, 32', 32'') is further configured to drive the second elongate member (30, 30', 30'') in a pivoting movement about the pivot axis.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to motor vehicles and, more particularly, to aerodynamic features of motor vehicles. INTRODUCTION

[0002] Modern motor vehicles typically have hydraulically actuated brakes on the front and rear wheels. In vehicles with a disc brake system, the hub of the vehicle's wheel is mounted on an axially concentric, circular disc made of a heat-conducting and wear-resistant metal. A vehicle-mounted brake caliper fits around a cutout of the circular disc. When a driver presses the brake pedal, hydraulic fluid in a brake hose connected to the caliper is pressurized, pressing the caliper's friction material pads against both sides of the rotating wheel disc. The frictional engagement between the brake pads and the rotating disc serves to slow and, if necessary, stop the vehicle's wheels. In drum brake systems, the vehicle wheel has an axially concentric, circular metal drum surface made of heat-conducting and wear-resistant metal.When braking, the pressurized hydraulic fluid in a brake hose pushes curved brake pads made of suitable friction material outwards against the wheel drum in order to slow down the vehicle wheel again and, if necessary, stop it.

[0003] For stylistic reasons and to control the distribution of sand, mud, fluids, and other road spray picked up by the rotating tire, vehicle wheels are generally partially enclosed within the vehicle body in a wheel arch. The wheel arch is a generally circular, partially enclosed cavity that is open at the bottom and at one fender or side panel of the vehicle, and extends partially into the vehicle body. The wheel arch contains the wheel, braking system, and often some suspension components such as springs and shock absorbers. The wheel arch is sized to accommodate the wheel and tire in all possible configurations, so its design allows for the expected range of tire movement. This can include suspension travel and, in the case of the front wheels, the expected range of angles when turning the steering wheel.Usually, the wheel arch is closed on the vehicle interior and around a significant portion of the tire circumference.

[0004] In general, the airflow around a moving vehicle contributes significantly to cooling the brake disc and drum surfaces as they become heated by the repeated wheel braking events of normal driving. This airflow is usually more than sufficient to cool brake discs, drums, and friction materials under most common driving conditions, although extra care may be needed when towing a trailer or driving in mountainous regions with long, steep grades. However, the hood, roof, rear end, and sides are designed more closely to reduce vehicle drag. Some drag-reducing design features, such as air dams, can also reduce the airflow available to cool frictionally heated brake body surfaces.

[0005] The document DE 10 2008 013 336 A1 discloses a motor vehicle comprising a movable wind deflector with an elongated element that can be driven in a pivoting movement about a pivot axis by means of an actuator controlled by a controller. The documents US 2008 / 0 100 071 A1, DE 10 2013 224 447 A1, US 2013 / 0 233 658 A1, and DE 10 2015 113 047 A1 disclose further exemplary air guidance systems for vehicles.

[0006] It is an object of the invention to provide a vehicle with which an optimal balance between a reduction in air resistance and cooling of the brakes is possible.

[0007] This object is achieved according to the invention by the features of claim 1 and by the features of claim 2. Advantageous further developments emerge from the subclaims.

[0008] Embodiments according to the present disclosure provide several advantages. For example, the present disclosure provides a system and method for meeting the brake cooling requirements of a high-performance motor vehicle while reducing vehicle drag. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of a motor vehicle according to an embodiment of the present disclosure; Fig. 2 is a bottom view of a motor vehicle according to an embodiment of the present disclosure; Fig. 3 is a flowchart illustration of a method for controlling a motor vehicle according to an embodiment of the present disclosure; The Fig. 4A and Fig. 4B are schematic representations of a vehicle according to an embodiment of the present disclosure; and The Fig. 5A and Fig. 5B are schematic illustrations of a vehicle according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0009] Embodiments of the present disclosure are described herein. It should be understood, however, that the disclosed embodiments are merely examples, and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be shown larger or smaller to illustrate the details of particular components. Therefore, the specific structural and functional details disclosed herein are not to be considered limiting, but merely as a representative basis. The various features shown and described with reference to any of the figures may be combined with features shown in one or more other figures to produce embodiments not explicitly shown or described.The illustrated combinations of features provide representative embodiments for typical applications. However, any combinations and modifications of the features consistent with the teachings of this disclosure may be undesirable for particular applications and implementations.

[0010] Now with reference to the Fig. 1 and Fig. 2, a first embodiment of a motor vehicle 10 according to the present disclosure is illustrated. The motor vehicle 10 is provided with a body 12. At least one vehicle wheel 14 is disposed below the body 12. A disc rotor 16 is mounted generally concentrically with the wheel 14. A pair of brake pads 18 are configured to frictionally engage the rotor 16 to decelerate the vehicle. The brake pads 18 are carried by pistons 20, which in turn are slidably supported by a brake caliper 22. A fluid line 24 supplies fluid to the brake caliper 22 such that an increase in line pressure in the fluid line 24 causes actuation of the pistons 20 and, thus, the brake pads 18. The brake pads 18 and the rotor 16 experience an increase in thermal energy upon frictional engagement.

[0011] A sensor 26 is configured to measure the temperature of the brake caliper 22. In an exemplary embodiment, the sensor 26 includes a temperature sensor configured to detect the fluid temperature of the fluid supplied from the fluid line 24. In further embodiments, other sensors may also be used, such as an infrared thermometer, to detect the temperature of the brake caliper 22. In an alternative embodiment, the sensor 26 is configured to detect a line pressure in the fluid line 24 and infer a temperature increase of the brake caliper 22 due to a line pressure drop.

[0012] An active wind deflector 28 is arranged in front of the vehicle wheel 14. The active wind deflector 28 comprises at least one movable element 30 which is coupled to one or more actuators 32. In the embodiment shown in the Fig. 1 and Fig. 2, the active wind deflector 28 includes two movable elements 30, each coupled to an actuator 32. The active wind deflector 28 has a cooling position, as shown in Fig. 1, and a locking position as shown in Fig. 2. The locking position and the cooling position have different underbody blocking profiles.

[0013] In the cooling position, the active wind deflector 28 is arranged in such a way that it directs air to the brake calliper 22 and thus provides cooling. In the Fig. In the embodiment illustrated in Figure 1, the movable elements 30 are arranged generally parallel to each other to form a passageway and thereby direct air to the brake caliper 22. The cooling position can be selected, for example, based on computational fluid dynamics (CFD) analyses or wind tunnel testing.

[0014] In the locked position, the active wind deflector 28 is arranged to direct the air around the vehicle wheel 14. In the Fig. In the embodiment illustrated in Figure 2, the movable elements 30 are arranged such that they generally abut one another, forming a deflection path for the vehicle wheel 14. The air is thereby directed around the vehicle wheel 14, thereby reducing drag. As with the cooling position, the locking position can be selected, for example, through CFD analysis or wind tunnel testing.

[0015] The actuator(s) 32 are configured to move the active wind deflector 28 between the blocking position and the cooling position. Fig. 1 and Fig. 2, the actuators 32 are configured to pivot the movable elements 30 between the positions about generally vertical pivot axes, as indicated by the arrows in Fig. 1. The actuators 32 may include electromechanical actuation units, such as solenoid valves, or any other suitable actuation unit. The free ends of the movable elements 30, i.e., the ends not coupled to the actuators 32, may swing freely or be supported by a rail, depending on the embodiment.

[0016] In some embodiments, the actuators 32 may be controlled to progressively change the position of the movable elements 30 from a plurality of intermediate positions between the locking position and the cooling position, thereby gradually increasing cooling when needed while maintaining the deflection effect to reduce drag.

[0017] In the Fig. 1 and Fig. In the embodiment illustrated in Figure 2, an active wind deflector 28 is associated with a front driver-side wheel arch. Other similar deflectors, not shown, may be associated with one or more of the other vehicle wheels. It should be noted that for some vehicles, it may be desirable to use a separate deflector for each wheel, while for other vehicles, a single deflector may provide the blocking and cooling function for multiple wheels.

[0018] The sensor 26 and the actuators 32 are all in communication with or controlled by the controller 34. The controller 34 is programmed to control the actuators 32 to move the active wind deflector 28 based at least in part on the readings from the sensor 26, as described below with respect to Fig. 3 is explained in more detail.

[0019] While depicted as a single unit, controller 34 may include one or more controllers, collectively referred to as a "controller." Controller 34 may include a microprocessor or central processing unit (CPU) in communication with various types of computer-readable storage devices or media. Computer-readable storage devices or media may include volatile and non-volatile memory in read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is persistent or non-volatile memory that may be used to store various operating variables while the CPU is powered off.Computer-readable storage devices or media may be implemented using any of a number of known storage devices, such as PROMs (programmable read-only memories), EPROMs (electrical PROMs), EEPROMs (electrically erasable PROMs), flash memory, or any other electrical, magnetic, optical, or combination storage devices capable of storing data, some of which represent executable instructions used by the controller in controlling the engine or vehicle.

[0020] With reference now to Fig. 3, a method for controlling a channel system according to the present disclosure is illustrated in a flowchart. The method begins in block 100. In an exemplary embodiment, the method is implemented by programming a controller, e.g., the controller shown in Fig. 1 illustrated control 34.

[0021] The wind deflector is controlled to the locked position, as illustrated at block 102. As explained above, in the locked position, the wind deflector is arranged to direct air around one or more vehicle wheels, thereby reducing vehicle drag and increasing fuel consumption.

[0022] As illustrated in block 104, a temperature of the brake caliper is detected. This can be done, for example, with the Fig. 1 illustrated sensor 26.

[0023] A determination is made as to whether the brake caliper temperature exceeds a predefined threshold, as illustrated in operation 106. The first predefined threshold is based on a desired operating temperature range of the braking system and may, for example, be on the order of 1,000 degrees Fahrenheit.

[0024] If the determination of operation 106 is negative, ie, the determined brake caliper temperature does not exceed the first threshold, control returns to block 104. The wind deflector is held in the locked position until a detected brake caliper temperature exceeds the first threshold.

[0025] If the determination of operation 106 is positive, ie, the determined brake caliper temperature exceeds the first threshold, the air deflector is controlled to the cooling position, as illustrated in block 108. As explained above, in the cooling position, the air deflector is arranged to direct air to one or more braking systems connected to vehicle wheels, thus providing cooling.

[0026] As illustrated in block 110, the temperature of the brake caliper is detected. As explained above, this can be done using the Fig. 1 illustrated sensor 26.

[0027] It is determined whether the brake caliper temperature drops below a second predefined threshold, as illustrated in operation 112. The second predefined threshold may be the same as or different from the first predefined threshold. In an exemplary embodiment, the second predefined threshold is less than the first predefined threshold to avoid a rapid transition between cooling and locking modes due to hysteresis.

[0028] If the determination of operation 112 is negative, ie, the detected brake caliper temperature does not fall below the second threshold, control returns to block 110. The wind deflector is held in the cooling position until the detected brake caliper temperature falls below the second threshold.

[0029] If the determination of operation 112 is positive, ie the detected brake caliper temperature does not fall below the second threshold, then control returns to block 102 and the wind deflector is controlled to the locking position.

[0030] Variations of the above are conceivable within the scope of the present disclosure.

[0031] With reference now to the Fig. 4A and Fig. 4B illustrates a second exemplary embodiment according to the present disclosure. In the embodiment of Fig. 4A and Fig. 4B, a vehicle 10' is provided with a wind deflector 28' coupled to an actuator 32'. The wind deflector 28' includes first and second movable members 30'. The actuator 32' is configured to pivot the first and second movable members 30' about a generally vertical pivot axis. The actuator 32' is controlled by a controller 34'. The controller is configured to control the actuator 32' to move the wind deflector 28' between a locking position, as shown in Fig. 4A, and a cooling position as shown in Fig. 4B, for example, according to a similar algorithm as in Fig. 3. In the locked position, the wind deflector 28' acts as an air dam, preventing air from passing under the vehicle 10' and thereby reducing air resistance. In the cooling position, the movable elements 30' are pivoted to present a different locking pattern, redirecting the air toward the vehicle wheels 14' to improve cooling of the vehicle brakes.

[0032] With reference now to the Fig. 5A and Fig. 5B, a third exemplary embodiment according to the present disclosure is illustrated. In the embodiment of Fig. 5A and Fig. 5B, a vehicle 10" is provided with a wind deflector 28" coupled to an actuator 32". The wind deflector 28" includes a movable member 30". The actuator 32" is configured to pivot the movable member 30" about a generally horizontal pivot axis extending laterally across the vehicle. The actuator 32" is controlled by a controller 34". The controller is configured to control the actuator 32" to move the wind deflector 28" between a locking position, as shown in Fig. 5A, and a cooling position as shown in Fig. 5B, for example, according to a similar algorithm as in Fig.3. In the locked position, the wind deflector 28" acts as an air dam, preventing air from passing under the vehicle 10" and thereby reducing air resistance. In the cooling position, the movable elements 30" are pivoted to present a different locking pattern, redirecting the air toward the vehicle wheels 14" to improve cooling of the vehicle brakes.

[0033] As will be appreciated by one of ordinary skill in the art, similar air flow systems can be used to selectively cool other components in a motor vehicle when needed.

[0034] As will be appreciated from the present disclosure, a system and method for balancing drag reduction and brake cooling for a high-performance motor vehicle is provided.

Claims

[1] Motor vehicle (10, 10', 10''), comprising: a body (12) with a bottom; a plurality of vehicle wheels (14, 14') arranged on the underside, each corresponding wheel of the plurality of vehicle wheels (14, 14') having a respective contact surface for contacting a driving surface, an underbody space being defined between the contact surfaces and the underside of the body (12); a movable wind deflector (28, 28', 28'') coupled to the underside and projecting into the underbody space, the movable wind deflector (28, 28', 28'') having a first position and a second position, the first position having a first blocking profile in the underbody space and the second position having a second blocking profile in the underbody space that is different from the first blocking profile; an actuator (32, 32', 32'') coupled to the movable wind deflector (28, 28', 28'') and configured to drive the movable wind deflector (28, 28', 28'') between the first position and the second position; and a controller (34, 34', 34'') configured to control the actuator (32, 32', 32'') in response to compliance with an operating condition to move the movable wind deflector (28, 28', 28'') from the first position to the second position, wherein the movable wind deflector (28, 28', 28'') comprises an elongated element (30, 30', 30'') having a first end and a second end, the first end being coupled to the actuator (32, 32', 32''), and the actuator (32, 32', 32'') being configured to drive the elongated element (30, 30', 30'') in a pivoting movement about a pivot axis passing through the first end, wherein the movable wind deflector (28, 28', 28'') comprises a second elongate member (30, 30', 30'') coupled to the actuator (32, 32', 32''), and wherein the actuator (32, 32', 32'') is further configured to drive the second elongate member (30, 30', 30'') in a pivoting movement about the pivot axis. [2] Motor vehicle (10, 10', 10''), comprising: a body (12) with a bottom; a plurality of vehicle wheels (14, 14') arranged on the underside, each corresponding wheel of the plurality of vehicle wheels (14, 14') having a respective contact surface for contacting a driving surface, an underbody space being defined between the contact surfaces and the underside of the body (12); a movable wind deflector (28, 28', 28'') coupled to the underside and projecting into the underbody space, the movable wind deflector (28, 28', 28'') having a first position and a second position, the first position having a first blocking profile in the underbody space and the second position having a second blocking profile in the underbody space that is different from the first blocking profile; a first actuator (32, 32', 32'') and a second actuator (32, 32', 32''), each coupled to the movable wind deflector (28, 28', 28'') and configured to drive the movable wind deflector (28, 28', 28'') between the first position and the second position; and a controller (34, 34', 34'') configured to control the actuators (32, 32', 32'') in response to compliance with an operating condition to move the movable wind deflector (28, 28', 28'') from the first position to the second position, wherein the movable wind deflector (28, 28', 28'') comprises a first elongate member (30, 30', 30'') having a first end and a second end, the first end being coupled to the first actuator (32, 32', 32''), and the first actuator (32, 32', 32'') being configured to drive the first elongate member (30, 30', 30'') in a pivoting movement about a pivot axis passing through the first end, wherein the movable wind deflector (28, 28', 28'') comprises a second elongate member (30, 30', 30'') coupled to the second actuator (32, 32', 32''), and wherein the second actuator (32, 32', 32'') is configured to drive the second elongate member (30, 30', 30'') in a pivoting movement. [3] Motor vehicle (10, 10', 10'') according to claim 1 or 2, wherein the movable wind deflector (28, 28', 28'') additionally has an intermediate position between the first position and the second position, and wherein the controller (34, 34', 34'') is further configured to, in response to compliance with a second operating condition, control the actuator (32, 32', 32'') or the first and second actuators (32, 32', 32'') to move the movable wind deflector (28, 28', 28'') to the intermediate position. [4] The motor vehicle (10, 10', 10'') of claim 1 or 2, further comprising a vehicle brake assembly and a temperature sensor configured to detect a current temperature of the vehicle brake assembly, wherein the operating condition includes the current temperature exceeding a first predetermined threshold. [5] Motor vehicle (10, 10', 10'') according to claim 4, wherein the controller (34, 34', 34'') is further configured to control the actuator (32, 32', 32'') or the first and second actuators (32, 32', 32'') to move the movable wind deflector (28, 28', 28'') from the second position to the first position in response to falling below a second predefined threshold. [6] Motor vehicle (10, 10', 10'') according to claim 5, wherein the second predefined threshold is smaller than the first predefined threshold. [7] Motor vehicle (10, 10', 10'') according to claim 1 or 2, wherein the pivot axis is generally vertical. [8] Motor vehicle (10, 10', 10'') according to claim 1 or 2, wherein the pivot axis is generally horizontal.

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