Vehicle, system, and method for controlling active aerodynamic elements

A vehicle includes a motor for propelling the vehicle and at least one active aerodynamic element configured to generate a variable amount of aerodynamic downforce on the vehicle when the vehicle is in motion. The vehicle also includes at least one driver input sensor configured to detect a driver input and generate a feedforward signal indicative of a desired behavior of the vehicle. The vehicle additionally includes a controller in communication with the at least one driver input sensor and the at least one active aerodynamic element and configured to regulate the at least one active aerodynamic element at least partially in response to the feedforward signal. A method for controlling such an active aerodynamic element and a system for controlling an aerodynamic downforce on a vehicle are also disclosed.

TECHNICAL FIELD

The disclosure generally relates to vehicles with active aerodynamic elements and associated control methods therefor.

BACKGROUND

Vehicles often utilize aerodynamic elements to change the airflow around the vehicle. The aerodynamic elements typically function to increase aerodynamic downforce on the vehicle to enhance the vehicle's dynamic handling characteristics. Such aerodynamic elements include, but are not limited to, spoilers, wings, and air dams. Typically, along with an increase in aerodynamic downforce created by such aerodynamic elements, aerodynamic drag on the vehicle, particularly at high speeds, is also increased.

Some vehicles utilize active aerodynamic elements. Such active elements may change shape and/or be repositioned to change the aerodynamic properties of the vehicle while the vehicle is in motion, typically to improve handling and response of the vehicle. Such active aerodynamic elements may also be utilized to assist in braking of the vehicle. Additionally, such active aerodynamic elements may be utilized to change an airflow directed toward a cooling system of the vehicle.

SUMMARY

According to one embodiment, a vehicle includes a motor for propelling the vehicle and at least one active aerodynamic element configured to generate a variable amount of aerodynamic downforce on the vehicle when the vehicle is in motion. The vehicle also includes at least one driver input sensor configured to detect a driver input and generate a feedforward signal indicative of a desired behavior of the vehicle. The vehicle additionally includes a controller in communication with the at least one driver input sensor and the at least one active aerodynamic element and configured to regulate the at least one active aerodynamic element at least partially in response to the feedforward signal.

Each of the at least one active aerodynamic element may include an actuator configured to either change a shape of or reposition the respective active aerodynamic element relative to the vehicle to thereby vary the amount of the aerodynamic downforce on the vehicle. In such a case, the controller can be configured to control the actuator of each active aerodynamic element at least partially in response to the feedforward signal.

The vehicle may also include a steering wheel, an accelerator device configured to regulate a torque output of the motor, and a brake lever configured to retard the motion of the vehicle. In such a case, the at least one driver input sensor can include at least one of a steering wheel sensor configured to detect a rotational position of the steering wheel, an accelerator device sensor configured to detect a position of the accelerator device, and a brake lever sensor configured to detect a position of the brake lever.

In the case where the at least one driver input sensor includes the steering wheel sensor, the controller can be configured to determine, using the detected rotational position of the steering wheel, that the desired behavior of the vehicle is a desired lateral acceleration of the vehicle during cornering. Additionally, in such a case, the generated feedforward signal can be indicative of the desired lateral acceleration.

The vehicle may also include at least one vehicle performance sensor in communication with the controller. Each of such vehicle performance sensors can be configured to detect actual behavior of the vehicle and generate a feedback signal indicative of the detected actual behavior of the vehicle.

The vehicle may additionally include a road wheel, wherein the motor is coupled to the road wheel to propel the vehicle. The at least one vehicle performance sensor can include at least one of a wheel speed sensor configured to detect a rotating speed of the road wheel, an accelerometer configured to detect lateral or longitudinal acceleration of the vehicle, and a yaw-rate sensor configured to detect an angular velocity of the vehicle.

The controller can be configured to determine an actual lateral acceleration of the vehicle using the at least one vehicle performance sensor. In such a case, the controller can be additionally configured to regulate the at least one active aerodynamic element in response to the desired lateral acceleration and the determined actual lateral acceleration of the vehicle, i.e., using both, the feedforward and the feedback signals.

Another embodiment of the disclosure is directed to a method for controlling such an active aerodynamic element.

Yet another embodiment of the disclosure is directed to a system for controlling an aerodynamic downforce on a vehicle.

DETAILED DESCRIPTION

Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” “front,” “back,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions. Moreover, the term “coupled,” as used herein, may denote either a direct connection between components or an indirect connection, where the subject components are not in physical contact with one another.

Referring to the figures, wherein like numerals indicate like parts throughout the several views, a vehicle100, a control system110, and method200are shown and described herein.

The vehicle100of the exemplary embodiment is an automobile. However, it should be appreciated that in other embodiments, the vehicle100may be implemented with a performance or racing vehicle, industrial vehicle, motorcycles, aircraft, watercraft, or any other similar apparatus.

The vehicle100of the exemplary embodiment includes a plurality of road wheels102. The road wheels102may operatively engage the ground, a roadway, and/or other surface as appreciated by those skilled in the art. For instance, a tire (not shown) may be coupled to one or more of the road wheels102, as is also appreciated by those skilled in the art. The vehicle100also includes a motor104for generating motion. The motor104is operatively connected or coupled to at least one of the road wheels102for rotating the subject wheel(s). The motor104may be an engine, e.g., an internal combustion engine, an electric motor, or other device for generating motion, as appreciated by those skilled in the art. The vehicle100may also include a transmission assembly106coupling the motor104to at least one of the road wheels102. The transmission assembly106may be configured to change the rotational speed ratio between the motor104and the road wheel102, as is readily appreciated by those skilled in the art.

The vehicle100of the exemplary embodiment includes a control system110for controlling aspects of the vehicle including speed and direction, as described in greater detail herein. The control system110includes at least one controller112. In the exemplary embodiment, a single controller112is shown, but those skilled in the art appreciate that multiple controllers112may be utilized. The controller112of the exemplary embodiment includes a processor114capable of performing calculations and executing instructions (i.e., running a program). The processor114may be implemented with a microprocessor, microcontroller, application specific integrated circuit (“ASIC”) or other suitable device. Of course, the controller112may include multiple processors114which may, or may not, be disposed in separate locations. The controller112of the exemplary embodiment also includes a memory116capable of storing data and in communication with the processor114. The memory116may be implemented with semiconductors (not shown) or any other suitable devices. Multiple memories116may also be utilized.

The vehicle100of the exemplary embodiment also includes a steering wheel120coupled to at least one of the road wheels102for turning the subject road wheels. As is appreciated by those skilled in the art, an operator of the vehicle100may turn, i.e., rotate, the steering wheel120to alter a trajectory of the subject vehicle. The control system110includes a steering wheel sensor122in communication with the controller112. The steering wheel sensor122is configured to detect the rotational position of the steering wheel120, often referred to as the steering wheel angle, and communicate the detected rotational position to the controller112. The steering wheel angle may also be utilized by the processor114to determine or compute a desired lateral acceleration of the vehicle100during desired vehicle cornering.

The vehicle100of the exemplary embodiment also includes an accelerator device, such as a switch or a pedal,124and a foot or hand operated brake lever, such as a pedal126. The accelerator device124is utilized by the operator of vehicle100to control the vehicle's speed, particularly via regulating the torque output of the motor104. The control system110includes an accelerator device sensor128configured to detect the position of the accelerator device124and, thus, the desired speed and/or desired change in speed of the vehicle100. The accelerator device sensor128is in communication with the controller112to communicate the detected position of the accelerator device124to the controller112. The brake lever126is generally utilized by the operator of the vehicle100to retard vehicle motion, i.e., to slow and/or stop the subject vehicle. The control system110includes a brake lever sensor130configured to detect the position of the brake lever126. The brake lever sensor130is also in communication with the controller112to communicate the detected position of the brake lever126to the controller112. The above described steering wheel sensor122, the accelerator device sensor128, and the brake lever sensor130may be generally identified as driver input sensors.

The controller112is configured to calculate gradients, that is, measures of change over time, for positions of the steering wheel120, the accelerator device124, and the brake lever126based on the readings provided by the steering wheel sensor122, the accelerator device sensor128, and the brake lever sensor130, respectively. The controller112can be configured to determine via the signal from the steering wheel sensor122that the desired behavior of the vehicle100is an intended or desired lateral acceleration during vehicle turning or cornering.

In addition to the previously described driver input sensors122,128,130, the control system110may also include various vehicle performance sensor(s) for detecting or measuring specific aspects of performance or actual behavior of the vehicle100. Such vehicle performance sensors may include, but are not limited to, an accelerometer(s)132for detecting or measuring longitudinal acceleration of the vehicle100, i.e., along an X-axis, and lateral acceleration of the vehicle, i.e., along a transverse Y-axis, and a yaw-rate sensor134for detecting an angular velocity of the vehicle around its vertical Z-axis, and wheel speed sensors136configured to detect rotating speeds of the respective road wheels102and thereby facilitate measurement of the road speed or velocity of the vehicle. The controller112can be additionally configured to acknowledge or verify that the vehicle100is in the process of turning or cornering via processing of the received signals from any of the respective vehicle performance sensors132,134,136.

The vehicle100includes at least one active aerodynamic element140. As shown inFIG. 1, the active aerodynamic element140is in operative communication with the controller112. The active aerodynamic element140may be configured to change shape and/or be repositioned to alter the aerodynamic properties of the vehicle100, while the vehicle is in motion. That is, the active aerodynamic element140can generate a variable amount of force, such as an aerodynamic downforce FDacting on the vehicle100substantially parallel to the Z-axis. In other words, as used herein, the term “aerodynamic downforce” is defined as an aerodynamic force acting on the vehicle100in a downward, normal direction relative to a direction of travel of the vehicle. As such the aerodynamic downforce FDis a negative lift force acting on the body of the vehicle100when the vehicle is in motion.

The downforce FDcan be employed to enhance handling characteristics of the vehicle100, specifically during cornering events, which can be detected by the position of the vehicle operator's steering wheel120, as understood by those skilled in the art. The increase of the downforce FDby aerodynamic elements is generally accompanied by a corresponding increase in aerodynamic drag force (not shown). The subject drag force can be desirable during vehicle braking events, for which reason a position of the vehicle's brake pedal126can be detected, as understood by those skilled in the art, and used as a signal for controlling the downforce FDvia one or more active aerodynamic elements140, as will be discussed in detail below.

For example, a fin-like rear spoiler embodiment (not shown) of the active aerodynamic element140may be movable up or down and/or tilted to alter the aerodynamic properties of the vehicle100. The active aerodynamic element140may also include an electric, mechanical, and/or hydraulic actuator (not shown), an electric motor (not shown), and/or other devices for changing shape and/or repositioning the subject active aerodynamic element relative to the vehicle100in response to specific commands issued by the controller112. The controller112may also be configured to regulate the active aerodynamic element(s)140during the determined desired vehicle cornering.

FIG. 2depicts a method200for controlling the active aerodynamic element(s)140, as described above with respect toFIG. 1. An exemplary embodiment of the method200shown inFIG. 2commences in frame202. In frame202the frame includes detecting and communicating via any of the driver input sensors122,128,130the respective driver input signal indicative of the desired behavior of the vehicle100when the vehicle is in motion. Following frame202, the method proceeds to frame204, where the method includes receiving, via the controller112, the at least one driver input signal. As described with respect toFIG. 1, these driver input signals may include, but are not limited to, a desired lateral acceleration (e.g., calculated from the detected position of the steering wheel120), a gradient of the steering wheel120angle, a desired brake force (e.g., calculated from the detected brake lever126position), a gradient of the desired brake force, a position of the accelerator device124, and a gradient of position of the accelerator device.

In other words, in frame204the method200may include receiving, via the controller112, driver input signal(s) as detected by any of driver input the sensors122,128,130. The received driver input signal(s) may also include a detection or determination of whether the vehicle100is operating on a racetrack or in a track mode, for example via a selection using a dedicated switch or other operator interface. The at least one driver input signal may be referred to as a “feedforward” signal because this signal is not dependent on the actual performance and/or behavior of the vehicle100, but is rather indicative of a desired or intended performance and/or behavior, i.e., target response, of the vehicle100as requested via a specific input by the driver.

It should be noted that the determination of whether the vehicle100is operating on a racetrack may be accomplished via a sensed or estimated lateral acceleration and/or speed of the vehicle, such as by utilizing data received by the controller112from the vehicle performance sensors132,134, and136. An exemplary technique for determination of whether the vehicle100is operating on a racetrack is described in the U.S. Pat. No. 6,408,229.

The method200also includes, in frame206, determining or calculating, via the controller112, an aerodynamic force target utilizing the at least one driver input signal. The aerodynamic force target may reflect a measure of the downforce FDthat is desired to be produced on the vehicle100, including by the at least one active aerodynamic element140. In the exemplary embodiment, calculating the aerodynamic force target may include converting and calibrating each received driver input signal from any of the driver input sensors122,128,130to common units. Calculating the aerodynamic force target may further include summing the driver input signals from one or more driver input sensors122,128,130to generate a continuous, feedforward signal in accordance with the target signal. In one embodiment, the aerodynamic force target would reflect a greater downforce FDwhen it is detected that the vehicle100is operating on a racetrack, than in non-racetrack situations. Such a control dichotomy can be beneficial to facilitate enhanced response of the vehicle100during competitive driving with high-g cornering experienced in vehicle racing, while favoring other factors, such as noise, comfort, and energy efficiency during general vehicle operation, for example, during a roadway commute.

In frame206the act of determining the aerodynamic force target may include generating a target signal of the vehicle100, i.e., a signal indicative of a vehicle target response based on the driver input signal(s) received in frame204, within one part of the controller112and then receiving the subject target signal within another part of the controller. For example, the target signal of the vehicle100can be generated by one processor114of the controller112, and then received via a separate processor114. In one example, the target signal is a desired yaw of the vehicle100that can be generated in response to the received driver input signal(s). Accordingly, in frame206, the act of determining the aerodynamic force target may include each of the detected driver input signal(s) and the generated target signal.

Following frame206, the method proceeds to frame208, where the method includes generating, via the controller112, the feedforward signal in response to the aerodynamic force target determined in frame206. Following frame208, the method advances to frame210. In frame210the method includes actuating the at least one active aerodynamic element140based at least partially on the calculated aerodynamic force target. That is, the active aerodynamic element140is moved and/or controlled to change shape in response to the feedforward signal generated by the controller112at least partially in response to the calculated aerodynamic force target.

Additionally, following frame206, but prior to frame208, the method may advance to frame212. In frame212the method may include determining, via the controller112using the detected rotational position of the steering wheel via the steering wheel sensor122, that the desired behavior of the vehicle100is a desired lateral acceleration of the vehicle during cornering.

After frame210, the method may proceed to frame214, where the method may include detecting actual behavior of the vehicle100and generating a feedback signal indicative of the detected actual behavior of the vehicle via any of the vehicle performance sensors132,134, and136. In frame214, the method may additionally include determining, via the controller112, the actual lateral acceleration of the vehicle100using at least one of the vehicle performance sensors132,134,136. For instance, the accelerometer(s)132may be used to provide lateral and/or longitudinal acceleration of the vehicle100, the yaw sensor134may be utilized to provide the yaw of the vehicle100, and/or wheel speed sensors136may be used to provide rotating speeds of the respective road wheels102, when the target signal indicative of the vehicle target response is any of the respective performance aspects of the vehicle100. Accordingly, in frame214, the method200may include determining, by the controller112, the aerodynamic force target utilizing both the driver input signal(s) from any driver input sensor(s)122,128,130and feedback signals from any vehicle performance sensor(s)132,134,136.

For example, the controller112can be configured to determine actual or current lateral acceleration of the vehicle100using the vehicle performance sensor(s)132,134, and136. The controller112can be additionally configured to regulate the active aerodynamic element(s)140to achieve the desired lateral acceleration of the vehicle100during cornering in response to the determined actual lateral acceleration, i.e., based on the feedback signal. In such a case, a plurality of driver's input signals detected via the sensor(s)122,128,130can be utilized by a driver-intent algorithm in the controller112to generate a set of feedforward signal components. The feedforward signal components can be combined with feedback from the vehicle100performance signals measured or detected via the respective sensors132,134, and136to generate, via the controller112, a target position for the at least one active aerodynamic element140. Accordingly, in frame214the controller112can generate a corrected or updated feedforward signal for the active aerodynamic element(s)140that is indicative of both the desired lateral acceleration and the detected actual lateral acceleration of the vehicle100.

After frame214, the method may advance to frame216. In frame216, the method may include regulating the active aerodynamic element(s)140to a revised target position using the updated feedforward signal. Following either of the frames210or216, the method200may loop back to frame202to resume control of the active aerodynamic element(s)140in response to an additional maneuver of the vehicle100, as detected by the vehicle performance sensors132,134,136, or another request from the driver, as detected by the driver input sensors122,128,130.

The vehicle100, system110, and the method200described herein provide numerous advantages. First, the response of the active aerodynamic elements140to the driver input can be improved which, in turn, can improve handling, i.e., controllability of the vehicle100. Improved handling of the vehicle100can be used by the driver to improve, i.e., lower, racetrack lap times. Second, the system110and method200using the described feedforward signal(s) indicative of driver input allow for more accurate adaptation of aerodynamic control to different driving styles. As a result, such adaptation of the active aerodynamic elements140to the driver input will provide greater consistency between drivers. Finally, the dynamic response of the vehicle100can be enhanced during cornering and other transient vehicle maneuvers.