JP2013151203A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle capable of easily and effectively reducing air resistance.SOLUTION: A vehicle 1 includes a vibration means 3 provided inside the outer wall face of the vehicle, and a control means 5 for forming a control signal to control the vibration means. The control means sets the frequency of vibration of a piezoelectric element on the basis of a vehicle speed, and generates the control signal to drive the vibration means at the set frequency. The vibration means vibrates at the frequency on the basis of the control signal to vibrate the outer wall face of the vehicle.

Description

  The present invention relates to a vehicle.

  Conventionally, attempts have been made to reduce the air resistance of a vehicle in order to improve the fuel efficiency of the vehicle. For example, in Patent Document 1, a vibration wall that vibrates due to the vibration of an engine is provided on the surface of the vehicle, so that the vibration wall is vibrated to reduce the air resistance of the vehicle. In this case, the vehicle is provided with vibration transmission means for transmitting the vibration of the engine to the vibration wall via the incompressible working fluid. As such a vibration transmission means, it is possible to include a cylinder mechanism that expands and contracts due to engine vibration to generate hydraulic pressure fluctuations. The piston of the cylinder mechanism is connected to the engine, and this cylinder mechanism is connected to the actuator via an oil passage filled with hydraulic oil. Then, the fluid pressure generated in the cylinder mechanism is transmitted to the actuator, and each under cover vibrates.

JP-A-9-226634

  However, in the case of Patent Document 1, since the vibration frequency of the engine vibration is determined depending on the driving state of the vehicle and the vibration condition is not appropriate for the vibration wall, the air resistance may not be reduced. .

  In addition, there is a problem that the cost is high because the configuration is complicated.

  Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a vehicle that can easily and effectively reduce air resistance.

  The vehicle according to the present invention is a vehicle including a vibration unit made of a piezoelectric element provided inside an outer wall surface of the vehicle, and a control unit that forms a control signal for controlling the vibration unit. And setting a vibration frequency of the vibration means based on the vehicle speed, and generating a control signal for driving the vibration means so as to be the set frequency, the vibration means based on the control signal It vibrates so that it may become this frequency, and vibrates the outer wall surface of the said vehicle. In the present invention, vibration can be easily generated by vibrating the piezoelectric element. Further, the frequency of the vibration of the piezoelectric element is set based on the vehicle speed, and a control signal for driving the vibration means is generated so as to be the set frequency, and the vibration means is based on the control signal. Thus, the outer wall surface of the vehicle can be easily vibrated at a predetermined frequency by vibrating the vehicle so as to have the frequency, and the air resistance can be effectively reduced. It is.

  Preferably, the control means sets an amplitude of the control signal based on the vehicle speed, and generates a control signal for driving the vibration means so as to be the set frequency. Thus, it is possible to reduce air resistance more effectively because the control means generates the control signal.

  The control means determines whether or not the vehicle is traveling at a predetermined vehicle speed or higher, vibrates the vibration means when the vehicle is in the traveling state, and stops the vibration means when the vehicle is not in the traveling state. It is preferable. This is because, when the vehicle is not in a traveling state at a predetermined vehicle speed or higher, the contribution of the air resistance in the traveling resistance is small.

  As a preferred embodiment of the present invention, the control means detects whether or not the vehicle is in the running state by detecting at least one or more selected from the vehicle speed, acceleration, fuel consumption rate, accelerator opening, and engine speed. Judging based on the results can be cited.

  The outer wall surface of the vehicle is preferably a floor surface of the vehicle. By being provided on the floor surface, it is possible to further reduce the air resistance of the vehicle.

  According to the vehicle of the present invention, it is possible to achieve an excellent effect of effectively reducing vibration and reducing air resistance.

The schematic diagram which shows the lower surface of a vehicle. The schematic diagram for demonstrating a vibration means. The graph for demonstrating the frequency and amplitude of a vibration means. The schematic diagram for demonstrating the vibration means in another embodiment. The schematic diagram for demonstrating the vibration means in another embodiment.

  An embodiment of the present invention will be described with reference to FIGS.

(Embodiment 1)
As shown in FIG. 1, the vehicle 1 has a floor panel 2 constituting an outer wall surface. In the present embodiment, the floor panel 2 includes a central portion 21 and a pair of front and rear wheels 11 and 22 and 23 configured as vibration portions. A vibration part is an area | region vibrated by the vibration means 3 shown in FIG. In this embodiment, although mentioned later in detail, the vibration part which is this floor surface vibrates, and the frictional resistance between a floor surface and an air flow can be reduced.

  Drive means 4 for driving the vibration means 3 and control means 5 for controlling the drive means 4 are connected to the vibration means 3. The vibration means 3 is provided inside the floor panel 2 (vehicle compartment side). One or more vibration means 3 are provided in each vibration part, and generate predetermined vibrations in the vibration part. The vibration means 3 includes a pair of electrodes 31 and a piezoelectric layer 32 sandwiched between the electrodes 31. The electrode 31 and the piezoelectric layer 32 only have to be made of a material used in a normal actuator device, and a metal such as gold can be used as the electrode 31. As the piezoelectric layer 32, ceramics normally used as a piezoelectric material, such as lead titanate, can be used.

  The drive unit 4 forms a drive waveform to be input to the electrode 31 based on a signal input from the control unit 5 described later in detail. When the formed drive waveform is input to the electrode 31 of the vibration means 3, the piezoelectric layer 32 vibrates and vibrates the vibration part of the floor panel 2 through the electrode.

The control means 5 acquires the vehicle speed detected by the vehicle speed sensor S1. In the present embodiment, the control means 5 determines whether or not the vehicle is in a traveling state faster than a predetermined speed from the acquired vehicle speed, and performs this control when the vehicle is in a traveling state faster than the predetermined speed. This is because the air resistance during traveling can be reduced by performing this control as described in detail below.
When control is started, the control means 5 obtains the optimum frequency and optimum amplitude of vibration of the vibration means 3 from this vehicle speed using a map (recorded in a recording unit (not shown) provided in the control means 5). The control unit 5 inputs a control signal corresponding to the obtained optimum frequency and optimum amplitude to the driving unit 4.

  That is, the control means 5 obtains the optimum frequency and optimum amplitude for reducing the air resistance most efficiently from the map based on the vehicle speed, forms a control signal corresponding to this, and inputs it to the drive means 4 for driving. The means 4 forms a drive waveform corresponding to the input control signal and inputs it to the vibration means 3. Thereby, the vibration means 3 vibrates at the optimum frequency and optimum amplitude based on the drive waveform to vibrate the vibration part. As the vibration part vibrates in this manner, it is possible to effectively reduce the air resistance of the vehicle as will be described in detail below. Further, the configuration is a simple configuration in which a piezoelectric element is provided on the floor panel, and a complicated configuration is not required, so that the cost can be reduced.

  Here, the optimum frequency and the optimum amplitude will be described. FIG. 3 (1) is a graph showing the frictional resistance change rate with respect to the frequency at a certain vehicle speed, and (2) is a graph showing the frictional resistance change rate with respect to the amplitude. When the frictional resistance change rate is 0, there is no change in the frictional resistance (air resistance). When the frictional resistance change rate is greater than 0, the resistance increases. When the frictional resistance change rate is less than 0, the frictional resistance decreases.

  As shown in FIG. 3, the frictional resistance change rate with respect to the frequency is 0 (that is, does not vibrate) when the frequency is f0, but becomes smaller than 0 as the frequency increases. Thereafter, the frictional resistance change rate becomes the smallest at the frequency f1 and starts to rise, and then the frictional resistance change rate becomes larger than 0 at the frequency f2.

  Further, the frictional resistance change rate with respect to the amplitude becomes smaller than 0 (that is, does not vibrate) as the amplitude increases when the amplitude is A0. Thereafter, the frictional resistance change rate becomes the smallest at the amplitude A1 and decreases to increase.

  From these results, it can be seen that the air resistance can be reduced by the vibration of the vibration part only when the vibration has a predetermined frequency (f2 or less). Further, the air resistance can be more effectively reduced by the vibration of the vibration part because the vibration has a predetermined frequency (near f1) and a predetermined amplitude (near A1), and the air resistance is most effectively reduced. Can be reduced when the frictional resistance change rate is the smallest, that is, when the vibration is at the optimum frequency f1 and the amplitude is at the optimum amplitude A1.

  The frequency and amplitude dependency of the frictional resistance change rate varies depending on the vehicle speed, but the frequency and amplitude dependency of the frictional resistance change rate has an optimum value in this way at any vehicle speed. It is thought that the shape becomes a valley.

  Therefore, in the present embodiment, the control means 5 determines the optimum frequency and the optimum amplitude of the vibration so that the vibration is the optimum frequency f1 and the amplitude is the optimum amplitude A1 based on the vehicle speed detected by the vehicle speed sensor S1. And a control signal corresponding to this is formed and input to the driving means 4. The drive unit 4 forms a drive waveform corresponding to the input signal and inputs the drive waveform to the vibration unit 3. Thereby, the vibration means 3 vibrates with the optimal frequency f1 and the optimal amplitude A1 based on the drive waveform, and vibrates the vibration part. As described above, the vibration portion vibrates at the optimum frequency f1 and the optimum amplitude A1, so that the air resistance of the vehicle can be most effectively reduced.

  In the present embodiment, the control means 5 is set based on the vehicle speed so that the optimum frequency f1 and the optimum amplitude A1 are obtained, but the present invention is not limited to this. For example, the frequency may be determined so that the frictional resistance change rate is equal to or less than a predetermined value X. What is necessary is just to set a frequency and an amplitude suitably according to the reduction rate of desired frictional resistance change rate.

(Embodiment 2)
Still another embodiment of the present invention will be described with reference to FIG.

  In this embodiment, the point which provided the cover part (undercover) as a vibration part in the lower surface of the floor panel 2 differs from embodiment mentioned above. In FIG. 4, the same reference numerals as those in FIGS. 1 to 3 denote the same components.

  As shown in FIG. 4, in the present embodiment, a cover member 51 that is an undercover is provided on the outer surface side of the floor panel 2. The cover member 51 is provided so as to cover each vibration part such as the central part 21 of the floor panel 2. The vibration means 3 is provided on the inner surface side of the floor surface portion 52 constituting the floor surface of the cover member 51. That is, when the vibration means 3 vibrates, the floor surface portion 52 vibrates.

  Further, the cover member 51 does not have a flange portion or the like as an example in the present embodiment, and its end is fixed to the floor panel 2 (not shown), but is connected across the edge of the floor surface portion 52. The wall surface portion may be configured to have a flange portion extended from the wall surface portion, and the flange portion may be fixed to the outer surface of the floor panel by a fixing member.

  In the present embodiment, since the floor surface of the vehicle 1 is substantially constituted by the floor surface portion 52, if the floor surface portion 52 vibrates due to the vibration means 3 vibrating at the above-described optimum frequency and optimum amplitude, As in the first embodiment, the resistance between the floor surface and the air flow can be reduced. In this case, for example, even if the floor panel has a high rigidity and is difficult to vibrate, if the cover member 51 is provided separately as in the present embodiment to form the floor surface (outer wall surface), the cover member Since 51 only needs to have rigidity enough to vibrate, it is easy to vibrate.

(Embodiment 3)
Another embodiment of the present invention will be described with reference to FIG. In FIG. 5, the same reference numerals as those in FIGS. 1 to 4 denote the same components. The control shown in FIG. 5 is different from the control shown in FIG. 2 in that acceleration is acquired from the acceleration sensor S2.

  As shown in FIG. 5, in this embodiment, the control means 5 acquires acceleration from acceleration sensor S2 besides vehicle speed. Then, the control means 5 determines whether or not the vehicle is in a predetermined traveling state based on the vehicle speed and acceleration. And the control means 5 does not form the signal according to a vehicle speed, when the acceleration acquired from acceleration sensor S2 is smaller than 0, ie, when the vehicle 1 is in a deceleration state. This is because when it is determined that the vehicle is in a decelerating state, it is preferable to stop the vibration and reduce the energy consumption of the vehicle, rather than suppressing the resistance between the floor and air. Thus, in this embodiment, energy consumption can also be reduced while reducing air resistance.

  Whether or not the vehicle is in a predetermined traveling state is detected based on whether or not the acceleration is a positive value in the present embodiment, but is not limited thereto. Other elements such as a fuel consumption rate, an accelerator opening degree, and an engine speed may be detected by a sensor or the like, and whether or not the vehicle is in a predetermined traveling state may be detected based on the detection result. For example, when the accelerator opening is 0, it can be determined that the vehicle is not in an acceleration state. Moreover, you may perform this control with the vehicle shown in Embodiment 2. FIG.

  In each embodiment mentioned above, although the vibration means 3 was provided in the member which comprises a floor surface among the outer wall surfaces of a vehicle, it is not limited to this. You may provide in the member which comprises another outer wall surface.

In each of the above-described embodiments, the optimum frequency and the optimum amplitude are obtained, but the present invention is not limited to this. For example, the control unit may be configured to obtain only the optimum frequency based on the vehicle speed. Also in this case, although not as much as each embodiment mentioned above, a frictional resistance change rate can be reduced and air resistance can be reduced. Further, for example, the control unit may derive only the optimum frequency, and the amplitude may be appropriately derived as a value that is not more than a predetermined frictional resistance change rate.
In the present embodiment, a piezoelectric element is exemplified as the vibration means, but the present invention is not limited to this. As long as vibration can be applied, for example, a motor or the like may be used.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Floor panel 3 Vibration means 4 Drive means 5 Control means 11 Wheel 21 Center part 31 Electrode 32 Piezoelectric layer 51 Cover member 52 Floor part S1 Vehicle speed sensor S2 Acceleration sensor

Claims (5)

A vehicle comprising vibration means provided inside an outer wall surface of the vehicle, and control means for forming a control signal for controlling the vibration means,
The control means sets a vibration frequency of the vibration means based on a vehicle speed, and generates a control signal for driving the vibration means so as to be the set frequency,
The said vibration means vibrates so that it may become this frequency based on this control signal, and vibrates the outer wall surface of the said vehicle.   2. The control means according to claim 1, wherein the control means sets an amplitude of the control signal based on the vehicle speed, and generates a control signal for driving the vibration means to have the set frequency. vehicle.   The control means determines whether or not the vehicle is traveling at a predetermined vehicle speed or higher, vibrates the vibration means if the vehicle is in the traveling state, and stops the vibration means if the vehicle is not in the traveling state. The vehicle according to claim 1 or 2, characterized by the above.   The control means determines whether or not the vehicle is in the traveling state based on at least one detection result selected from the vehicle speed, acceleration, fuel consumption rate, accelerator opening, and engine speed. The vehicle according to claim 3.   The vehicle according to any one of claims 1 to 4, wherein the outer wall surface of the vehicle is a floor surface of the vehicle.

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