vehicle

Abstract

The present invention provides a vehicle equipped with an underbody cover that can be moved up and down, and which can reduce the loss of kinetic energy by lowering the underbody cover while driving. [Solution] The vehicle comprises a pair of left and right front wheels 11, an under cover 12, and a drive unit. The under cover 12 is positioned in front of the front wheels 11 in the longitudinal direction and between the front wheels 11 in the vehicle width direction, and is provided to cover the bottom surface of the vehicle body. The drive unit has an actuator and a link mechanism and moves the under cover 12 up and down. In the vehicle, when the under cover 12 is in a lowered and deployed state, it has a rear portion (bottom flat portion) 12b between the rear edge portion 12e and the front portion 12a, where the bottom surface 12c is parallel to the road surface.

Description

Technical Field

[0001] The present invention relates to a vehicle, and particularly to a structure of a front lower portion of a vehicle.

Background Art

[0002] Vehicles are required to reduce eddy currents generated during traveling to reduce kinetic energy loss. When a vehicle is traveling, air flows into the lower portion of the vehicle from between the front bumper and the road surface, and eddy currents may be generated below the vehicle, resulting in kinetic energy loss. Structures intended to suppress the generation of such eddy currents below the vehicle are disclosed in Patent Documents 1 to 3.

[0003] Patent Documents 1 and 2 disclose a vehicle provided with an undercover arranged to extend from a lower portion of a front end of a front bumper to a position near a rear end of a front wheel. The undercover has a structure in which a front cover portion disposed forward of a front end portion of a wheel house and a rear cover portion disposed rearward of the front end portion of the wheel house are connected to each other. The undercover is connected to an actuator, and is configured to be capable of state change between a stowed state where a connecting portion between the front cover portion and the rear cover portion is lifted upward, and a deployed state where the connecting portion is lowered downward. In the undercover in the deployed state, the front cover portion is inclined such that its height is displaced upward as it goes forward from the connecting portion, and the rear cover portion is provided so as to be inclined such that its height is displaced upward as it goes rearward from the connecting portion.

[0004] Patent Document 3 discloses a vehicle including flow regulating members (undercovers) disposed on each of left and right sides in a vehicle width direction, and an air actuator that raises / lowers the flow regulating members. Each flow regulating member is disposed in front of each of left and right front wheels. When the flow regulating members are brought into a lowered state by the air actuator, the lower surface of each flow regulating member is provided with a curved surface whose height is displaced from above to below as it goes from the front to the rear.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-10984 [Patent Document 2] U.S. Patent Application Publication No. 2023 / 0099045 [Patent Document 3] Japanese Patent Publication No. 2007-30549 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the structures disclosed in the above-mentioned Patent Documents 1-3 are considered to have room for improvement in reducing the loss of kinetic energy during vehicle operation. Specifically, when a vehicle is in motion, the air flowing beneath the vehicle also collides with the tire tread at the front end of the front wheel. For this reason, the structures disclosed in Patent Documents 1-3 are considered to have room for improvement in suppressing the generation of vortices near the front end of the front wheel, thereby reducing the loss of kinetic energy during vehicle operation.

[0007] Specifically, in the structures disclosed in the above-mentioned Patent Documents 1-3, the under cover is arranged such that, in the deployed state, the gap with the road surface gradually narrows from the front of the vehicle towards the front end of the front wheel, resulting in high air pressure directly in front of the front wheel. Therefore, in the structures disclosed in Patent Documents 1-3, it is thought that the air flowing between the under cover and the road surface does not hit the front end of the front wheel (tire tread) straight in the longitudinal direction, but rather hits it at an angle. Thus, it is thought that there is room for further improvement in the structures disclosed in Patent Documents 1-3 to reduce the loss of kinetic energy.

[0008] The present invention aims to solve the above-mentioned problems and provides a vehicle equipped with an under cover that can move up and down, and which can reduce the loss of kinetic energy by lowering the under cover while driving. [Means for solving the problem]

[0009] A vehicle according to one aspect of the present invention comprises a pair of left and right front wheels, an under cover, and a drive unit. The pair of left and right front wheels are positioned at both ends in the width direction of the vehicle at the front of the vehicle. The under cover is positioned in front of the pair of left and right front wheels in the longitudinal direction of the vehicle, between the pair of left and right front wheels in the width direction of the vehicle, and is provided to cover the bottom surface of the vehicle body. The drive unit moves the under cover up and down.

[0010] In the vehicle according to this embodiment, when the under cover is in an extended state lowered by the drive unit, the portion in front of the rear edge has a flat bottom surface where the bottom surface is parallel to the road surface.

[0011] The vehicle according to the above embodiment is equipped with an under cover having a flat bottom portion. The flat bottom portion of the under cover is the part that is parallel to the road surface when it is in the deployed state. Therefore, when the vehicle according to the above embodiment is driven with the under cover deployed, the air pressure flowing backward between the bottom surface of the flat bottom portion of the under cover and the road surface decreases as it approaches the trailing edge of the flat bottom portion. Thus, in a vehicle equipped with an under cover having a flat bottom portion, when the vehicle is driven with the under cover deployed, air hits the front wheels straight in the front-rear direction, making it possible to reduce the loss of kinetic energy.

[0012] Furthermore, since the vehicle according to the above embodiment is equipped with a drive unit that moves the under cover up and down, it is possible to drive with the under cover raised without lowering it when driving on a road surface with many irregularities or when the under cover and its surrounding parts are frozen in a low-temperature environment. Therefore, the vehicle according to the above embodiment can suppress deformation and damage to the under cover and its surrounding parts caused by driving and the up and down movement of the under cover.

[0013] In the above, "parallel" includes not only cases where the bottom surface of the flat section of the underbody cover is perfectly parallel to the road surface, but also cases where it is slightly inclined to the road surface (for example, 2 degrees or less). The same applies hereafter.

[0014] In the vehicle according to the above embodiment, a front bumper may be further provided, which is positioned in front of the pair of left and right front wheels and extends in the width direction at the front end of the vehicle. In this case, the front portion of the under cover may further have a front portion that is continuous with the front end of the bottom flat portion and extends to the vicinity of the front end of the front bumper. Furthermore, the front portion of the under cover may be composed of a smooth curved surface such that the bottom surface is gradually displaced upward from the point of continuity with the bottom flat portion towards the vicinity of the front end of the front bumper.

[0015] In the above-described vehicle, the front bottom surface of the underbody cover is composed of a smooth curved surface, so that the air introduced below the front bumper is guided along the front bottom surface to below the flat bottom section. For this reason, the above-described vehicle is suitable for reducing the loss of kinetic energy during driving compared to a vehicle in which there is a step or the like in front of the flat bottom section of the underbody cover.

[0016] In the vehicle according to the above embodiment, the vehicle may further include a control unit. The control unit acquires vehicle information of the vehicle and, based on the acquired vehicle information, issues a command to the drive unit to raise or lower the under cover.

[0017] The vehicle according to the above embodiment is equipped with a control unit that issues commands to the drive unit to raise / lower based on acquired vehicle information. Therefore, under possible conditions, the underbody cover can be lowered to reduce kinetic energy loss, while under conditions where the underbody cover is not suitable, the underbody cover can be raised to suppress deformation and damage to the underbody cover and its surrounding parts. Thus, the vehicle according to the above embodiment is more suitable for reliably reducing kinetic energy loss and suppressing deformation and damage to the underbody cover and its surrounding parts compared to when the driver commands the drive unit to raise / lower.

[0018] In the vehicle according to the above embodiment, the vehicle may further include an outside temperature measuring unit and a vehicle speed measuring unit. The outside temperature measuring unit measures the outside temperature. The vehicle speed measuring unit measures the vehicle's speed. In this case, the control unit may acquire outside temperature information related to the outside temperature input from the outside temperature measuring unit and vehicle speed information related to the vehicle speed input from the vehicle speed measuring unit as the vehicle information.

[0019] In the above-described vehicle, the control unit acquires outside temperature information and vehicle speed information as vehicle information, and issues an upward / downward command to the drive unit based on the acquired information. Therefore, if the outside temperature is low and there is a concern about the road surface freezing or freezing of the underbody cover and surrounding mechanisms, the underbody cover will not be lowered even if the vehicle speed is high. Also, if the vehicle speed is low, it is presumed that the vehicle is driving in an urban area, so the underbody cover will not be lowered. As a result, in the above-described vehicle, when the outside temperature is relatively low or the vehicle speed is relatively low, the underbody cover can be raised to suppress deformation and damage to the underbody cover and surrounding parts.

[0020] On the other hand, in the case of the vehicle described above, if the outside temperature is relatively high and the vehicle speed is judged to be relatively high, the under cover is lowered because freezing and urban driving conditions are not expected. This suppresses the generation of vortices near the front end of the front wheels and reduces the loss of kinetic energy.

[0021] In the vehicle according to the above aspect, the control unit may include a reference map storage unit that pre-stores a reference map in which an outside air temperature threshold and a vehicle speed threshold are defined as thresholds for raising / lowering the undercover.

[0022] In the vehicle according to the above aspect, since the reference map in which the outside air temperature threshold and the vehicle speed threshold are defined is pre-stored in the reference map storage unit of the control unit, the control unit can acquire outside air temperature information and vehicle speed information, and determine raising / lowering of the undercover based on these pieces of information and the reference map. Therefore, in the vehicle according to the above aspect, the control unit can perform the determination of raising / lowering of the undercover based on the vehicle information (outside air temperature information, vehicle speed information).

[0023] In the vehicle according to the above aspect, when the control unit determines from the outside air temperature information that the outside air temperature is equal to or higher than the outside air temperature threshold, and determines from the vehicle speed information that the vehicle speed is equal to or higher than the vehicle speed threshold, the control unit may issue a command to the drive unit to lower the undercover.

[0024] The vehicle according to the above aspect lowers the undercover only when it is determined from the acquired vehicle information that the outside air temperature is equal to or higher than the outside air temperature threshold and the vehicle speed is equal to or higher than the vehicle speed threshold, so the conditions such as freezing and urban area traveling are not assumed, and deformation and damage of the undercover and its peripheral portions can be suppressed even when the undercover is lowered. By lowering the undercover, generation of eddy currents near the front end of the front wheels can be suppressed, and loss of kinetic energy can be reduced.

[0025] In the vehicle according to the above aspect, the drive unit may include an actuator and a link mechanism unit. The actuator is fixed to the perimeter frame. The link mechanism unit connects the actuator and the undercover.

[0026] In the vehicle according to the above embodiment, the drive unit comprises an actuator and a linkage mechanism. Therefore, the vehicle according to the above embodiment can reduce manufacturing costs without employing a special structure for raising / lowering the under cover.

[0027] Furthermore, in the vehicle according to the above embodiment, since the actuator is fixed to the perimeter frame, the height positions of the under cover when raised and lowered relative to the underside of the vehicle can be reliably defined. That is, since the perimeter frame does not undergo vertical displacement relative to the structural members of the vehicle body, fixing the actuator to the perimeter frame is suitable for defining the raised and lowered positions of the under cover.

[0028] Furthermore, since the perimeter frame is located at the front of the vehicle and close to where the under cover is to be installed, there is no need to use long brackets or other intermediate components to secure the actuator. Therefore, the actuator can be securely fixed to the vehicle body. [Effects of the Invention]

[0029] In each of the above embodiments, the vehicle can reduce kinetic energy loss by raising the under cover to suppress deformation and damage to the under cover and its surrounding parts during driving, and by lowering the under cover to suppress the generation of vortices near the front end of the front wheels. [Brief explanation of the drawing]

[0030] [Figure 1] This is a perspective view showing the front lower part of the vehicle according to the embodiment. [Figure 2] This is a bottom view showing the front lower part of the vehicle. [Figure 3] This is a schematic diagram showing the structure related to the movement of the underbody cover. [Figure 4] (a) is a side view showing the deployed state with the under cover lowered, and (b) is a side view showing the stowed state with the under cover raised. [Figure 5] This is a side view illustrating the placement and shape of the underbody cover. [Figure 6] This is a bottom view diagram illustrating the shape of the underbody cover. [Figure 7] This is a cross-sectional view illustrating the positional relationship between the undercover and the PT cover in their deployed state. [Figure 8] This is a block diagram showing the control configuration related to the movement of the underbody cover. [Figure 9] This diagram shows the reference maps that are pre-stored in the reference map storage unit of the control unit. [Figure 10] This is a flowchart illustrating the movement control of the underbody cover performed by the control unit. [Figure 11] (a) is a schematic diagram showing the under cover in the deployed state in a vehicle according to the embodiment, (b) is a graph showing the pressure change in the longitudinal direction under the under cover, and (c) is a schematic diagram for explaining the airflow at the front underside of the vehicle. [Figure 12] (a) is a schematic diagram showing the under cover in the deployed state of a vehicle relating to the comparative example, (b) is a graph showing the pressure change in the longitudinal direction under the under cover, and (c) is a schematic diagram to explain the airflow at the front underside of the vehicle. [Modes for carrying out the invention]

[0031] Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are illustrative examples of the present invention, and the present invention is not limited to these embodiments except for its essential configuration.

[0032] Furthermore, in the diagrams used in the following explanation, "FR" indicates the front of the vehicle, "RR" indicates the rear of the vehicle, "LH" indicates the left side of the vehicle, "RH" indicates the right side of the vehicle, "UP" indicates the top of the vehicle, and "LO" indicates the bottom of the vehicle.

[0033] 1. Structure of the front lower part of vehicle 1 The structure of the front lower part of vehicle 1 according to this embodiment will be explained with reference to Figures 1 to 3.

[0034] As shown in Figure 1, the vehicle 1 is equipped with a pair of left and right front wheels 11 (left front wheel 11L, right front wheel 11R), an under cover 12, a front bumper 13, and a pair of left and right deflectors 14 at the front lower part of the vehicle. The pair of left and right front wheels 11 are positioned at both ends in the width direction of the vehicle at the front of the vehicle 1.

[0035] The front bumper 13 is positioned in front of the pair of left and right front wheels 11 and extends in the width direction at the front end of the vehicle 1. The under cover 12 is positioned in front of the pair of left and right front wheels 11 in the front-rear direction and in the area between the left front wheel 11L and the right front wheel 11R in the width direction. The under cover 12 is provided to cover the bottom surface of the vehicle body in the said area. In this embodiment, the under cover 12 is formed using a resin material (for example, PP: polypropylene).

[0036] The left and right pair of deflectors 14 are each positioned directly in front of the front wheels 11. Furthermore, as shown in Figure 2, the deflectors 14 are positioned on both outer sides in the vehicle width direction relative to the under cover 12. In this embodiment, the deflectors 14 are formed using elastomer as an example.

[0037] As shown in Figure 2, the vehicle 1 further includes a powertrain under cover (PT cover) 15 located behind the under cover 12, in the area between the left front wheel 11L and the right front wheel 11R. The PT cover 15 is provided to cover the underside of the powertrain (e.g., engine and traction motor) mounted in the powertrain room.

[0038] Furthermore, as shown in Figure 3, the vehicle 1 includes an actuator 17 and a link mechanism 16 that connects the actuator 17 and the under cover 12. The actuator 17 and the link mechanism 16 constitute a drive unit that moves the under cover 12 up and down. The actuator 17 is fixed to the perimeter frame 18.

[0039] The under cover 12 is configured to move up and down as indicated by arrow A by the drive of the actuator 17. The configuration related to the drive control of the actuator 17 will be described later.

[0040] 2. Up and down movement of undercover 12 As described above, the under cover 12 is configured to be able to be raised and lowered by a drive unit including an actuator 17. In the vehicle 1 according to this embodiment, the under cover 12 can change between a deployed state, where it is lowered, and a retracted state, where it is raised. The deployed state and the retracted state of the under cover 12 will be explained with reference to Figure 4.

[0041] As indicated by arrow B1 in Figure 4(a), the under cover 12 can assume a position where it protrudes below the lower edge 13a of the front bumper 13 (deployed state).

[0042] On the other hand, as shown by arrow B2 in Figure 4(b), the under cover 12 can be positioned in a way that at least a portion of it is stored inside the front bumper 13 (stored state). In this embodiment, one example of the stored state is that a portion of the under cover 12 protrudes below the lower edge 13a of the front bumper 13, but a configuration in which the entire under cover 12 rises above the lower edge 13a of the front bumper 13 may also be adopted.

[0043] 3. Detailed structure of Undercover 12 The detailed structure of the under cover 12 will be explained using Figures 5 and 6. Figure 5 is a side view of the under cover 12 in its deployed state, and Figure 6 is a bottom view of a part of the under cover 12, viewed from below.

[0044] As shown in Figure 5, the under cover 12 is provided such that the front portion 12a and the rear portion 12b are continuous in the front-rear direction. The rear portion 12b of the under cover 12 extends forward from the trailing edge portion 12e, which is located in front of the front end (front end of the tire tread) 11a of the front wheel 11, when deployed, and has a flat bottom surface 12c. The rear portion 12b of the under cover 12 is provided such that the bottom surface 12c is parallel to the road surface when deployed. In other words, the rear portion 12b of the under cover 12 is a flat bottom portion.

[0045] In the above, "parallel" includes not only cases where the bottom surface of the flat section of the underbody cover is perfectly parallel to the road surface, but also cases where it is slightly inclined to the road surface (for example, 2 degrees or less). The same applies hereafter.

[0046] The front portion 12a of the under cover 12 is continuous with the rear portion 12b, and is composed of a smooth curved surface such that the bottom surface 12c gradually displaces upward as it moves from the point of continuity with the rear portion 12b towards the vicinity of the front end 13b of the front bumper 13. The front portion 12a is provided with, for example, a radius of curvature R1. In this embodiment, the radius of curvature R1 is, for example, 30 mm to 70 mm.

[0047] In the deployed state, the under cover 12 is positioned such that the front end of its front portion 12a is located behind the front end 13b of the front bumper 13 by a dimension G. In this embodiment, dimension G is, for example, 70 mm to 90 mm.

[0048] As shown in Figure 6, when the under cover 12 is viewed from below, the rear portion 12b is provided such that its outer edge in the vehicle width direction is aligned with the longitudinal direction of the vehicle 1. The under cover 12 is provided with a rear edge portion 12e that is straight and aligned with the vehicle width direction. That is, the rear edge portion 12e of the under cover 12 is formed to be straight and not inclined with respect to the vehicle width direction, nor does a part of it protrude toward the rear.

[0049] The front portion 12a has a front corner portion 12d that has an arc shape with a radius of curvature R2. In this embodiment, the radius of curvature R2 is, for example, 20 mm to 200 mm.

[0050] Here, when the undercover 12 is in the deployed state, if the length of the front part 12a in the front-rear direction is L12a and the length of the rear part 12b in the front-rear direction is L12b, then L12a and L12b are provided to satisfy the following relationship. 300mm≦(L12a+L12b)≦500mm (1)

[0051] 4. Height position of the undercover 12 in the deployed state The height position of the under cover 12 in the deployed state will be explained using Figure 7. Figure 7 is a schematic cross-sectional view showing the under cover 12 in the deployed state and the PT cover 15 positioned behind the under cover 12.

[0052] As shown in Figure 7, in the unfolded state, the under cover 12 is positioned such that its bottom surface 12c is at approximately the same height as the bottom surface 15a of the PT cover 15 at its rear edge 12e. However, there may be a slight difference in height between the bottom surface 12c of the under cover 12 and the bottom surface 15a of the PT cover 15. For example, there may be a difference in height equal to the thickness of the under cover 12.

[0053] 5. Control configuration for the movement of the under cover 12 The control configuration related to the movement (up and down movement) of the under cover 12 will be explained using Figures 8 and 9.

[0054] As shown in Figure 8, the vehicle 1 further comprises an outside temperature measurement unit 19, a vehicle speed measurement unit 20, and a control unit 21. The outside temperature measurement unit 19 measures the outside temperature around the vehicle 1 and inputs the measured outside temperature information to the control unit 21.

[0055] The vehicle speed measurement unit 20 measures the driving speed (vehicle speed) of the vehicle 1 while it is in motion and inputs the measured vehicle speed information to the control unit 21.

[0056] The control unit 21 is configured with a microprocessor including an MPU / CPU, ASIC, ROM, RAM, etc., and memory. The control unit 21 executes firmware etc. pre-stored in memory to acquire outside temperature information and vehicle speed information as vehicle information and executes drive control of the actuator 17.

[0057] The control unit 21 includes a reference map storage unit 211, a cover state determination unit 212, and an actuator drive command unit 213. The reference map storage unit 211 pre-stores a reference map in which an outside temperature threshold and a vehicle speed threshold are defined as thresholds for raising / lowering the under cover 12.

[0058] As shown in Figure 9, the reference map stored in the reference map storage unit 211 defines an ambient temperature threshold Ts, which is the ambient temperature threshold for raising or lowering the under cover 12, and a vehicle speed threshold Vs, which is the vehicle speed threshold. The ambient temperature threshold Ts and the vehicle speed threshold Vs may differ depending on the destination of the vehicle 1. In this embodiment, as an example, the ambient temperature threshold Ts is defined to be in the range of 5°C to 7°C, and the vehicle speed threshold Vs is defined to be in the range of 45 km / h to 60 km / h.

[0059] The cover state determination unit 212 determines whether the under cover 12 should be in the deployed state (lowered state) or the retracted state (upward state) based on the acquired outside temperature information and vehicle speed information, and the reference map stored in the reference map storage unit 211.

[0060] The actuator drive command unit 213 issues a drive command to the actuator 17 based on the result determined by the cover state determination unit 212.

[0061] 6. Drive control of actuator 17 performed by control unit 21 The method for controlling the drive of the actuator 17, which is performed by the control unit 21, will be explained with reference to Figure 10.

[0062] As shown in Figure 10, the control unit 21 determines whether the ambient temperature T obtained from the ambient temperature measurement unit 19 is lower than the ambient temperature threshold Ts defined in the reference map (see Figure 9) (step S1). If the control unit 21 determines that the ambient temperature T is lower than the ambient temperature threshold Ts (step S1: YES), the cover state determination unit 212 decides to put the under cover 12 into the retracted state, and the actuator drive command unit 213 issues an upward command to the actuator 17 (step S3).

[0063] On the other hand, if the control unit 21 determines that the outside temperature T is the same as or higher than the outside temperature threshold Ts (step S1: NO), it determines whether the vehicle speed V obtained from the vehicle speed measurement unit 20 is lower than the vehicle speed threshold Vs defined in the reference map (see Figure 9) (step S2). If the control unit 21 determines that the vehicle speed V is lower than the vehicle speed threshold Vs (step S2: YES), the cover state determination unit 212 decides to put the under cover 12 into the retracted state, and the actuator drive command unit 213 issues an upward command to the actuator 17 (step S3).

[0064] In response, if the control unit 21 determines that the vehicle speed V is equal to or higher than the vehicle speed threshold Vs (step S2: NO), the cover state determination unit 212 decides to deploy the under cover 12, and the actuator drive command unit 213 issues a lowering command to the actuator 17 (step S4). That is, in the vehicle 1 according to this embodiment, if the control unit 21 determines that the outside temperature T is equal to or higher than the outside temperature threshold Ts, and the vehicle speed V is equal to or higher than the vehicle speed threshold Vs, it issues a command to the drive unit, including the actuator 17, to lower the under cover 12.

[0065] The control unit 21 repeatedly executes steps S1 to S4 when the vehicle 1 is in the ignition state.

[0066] 7. Effects The vehicle 1 according to this embodiment is equipped with an under cover 12 having a rear portion 12b which is a flat bottom portion. The rear portion 12b of the under cover 12 is the part that is parallel to the road surface when the under cover 12 is deployed. Therefore, when the vehicle 1 is driving with the under cover 12 deployed, the air pressure flowing backward between the bottom surface 12c of the rear portion 12b of the under cover 12 and the road surface decreases as it approaches the rear edge 12e of the under cover 12.

[0067] Therefore, in a vehicle 1 equipped with an under cover 12 having a rear portion 12b which is a flat bottom portion, when the vehicle is driven with the under cover 12 deployed, air hits the front wheels 11 in a straight line along the longitudinal direction, making it possible to reduce the loss of kinetic energy. This will be explained in detail with reference to Figures 11 and 12. Figure 11 shows the air pressure under the under cover 12 and the airflow at the front bottom of the vehicle in vehicle 1 according to this embodiment. Figure 12 shows the air pressure under the under cover 92 and the airflow at the front bottom of the vehicle in a comparative example vehicle.

[0068] As shown in Figure 12(a), the vehicle in the comparative example is equipped with an under cover 92 at the front lower part of the vehicle, which is inclined such that the gap between the bottom surface of the rear 92b and the road surface narrows as it moves from front to rear. As shown in Figure 12(b), the air pressure below the under cover 92 increases as it moves from front to rear. Therefore, in the vehicle in the comparative example, as shown in Figure 12(c), the air introduced from the front is deflected outward in the vehicle width direction, and the air hitting the front wheels is directed diagonally outward. From this, it is thought that vortices are generated near the tire treads of the front wheels, resulting in a large loss of kinetic energy.

[0069] In contrast, as shown in Figure 11(a), the vehicle 1 according to this embodiment is equipped with an under cover 12 at the front lower part of the vehicle 1, which has a rear portion 12b that is parallel to the road surface when deployed. As shown in Figure 11(b), the air pressure below the under cover 12 decreases as it goes from the front to the rear. Therefore, in the vehicle 1 according to this embodiment, as shown in Figure 11(c), the air introduced from the front flows straight along the longitudinal direction and hits the front wheel 11 straight. As a result, the generation of vortices near the front end 11a (near the tire tread) of the front wheel 11 is suppressed, and the loss of kinetic energy during driving can be kept to a minimum.

[0070] Furthermore, since the vehicle 1 according to this embodiment is equipped with a drive unit (actuator 17, link mechanism 16) for moving the under cover 12 up and down, it is possible to drive with the under cover 12 raised without lowering it when driving on a road surface with large irregularities or when the under cover 12 and its surrounding parts are frozen at low temperatures. Thus, the vehicle 1 can suppress deformation and damage to the under cover 12 and its surrounding parts caused by driving and the up and down movement of the under cover 12.

[0071] The interpretation of "parallel" in the above context is the same as described above.

[0072] Furthermore, in this embodiment, since the bottom surface 12c of the front portion 12a of the under cover 12 of the vehicle 1 is composed of a smooth curved surface, the air introduced below the front bumper 13 flows along the bottom surface 12c of the front portion 12a and is guided downward to the rear portion (bottom flat portion) 12b without separation. For this reason, the vehicle 1 is suitable for reducing the loss of kinetic energy during driving compared to cases in which there is a step or the like in front of the bottom flat portion of the under cover.

[0073] Furthermore, the vehicle 1 according to this embodiment is equipped with a control unit 21 that issues commands to the actuator 17 to raise / lower based on acquired vehicle information. Therefore, under possible conditions (when both step S1 and step S2 are NO), the under cover 12 can be lowered to reduce kinetic energy loss, while when the conditions are not met (when at least one of step S1 and step S2 is NO), the under cover 12 can be raised to suppress deformation and damage to the under cover 12 and its surrounding parts. Thus, the vehicle 1 is more suitable for reliably reducing kinetic energy loss and suppressing deformation and damage to the under cover 12 and its surrounding parts compared to when the driver commands the actuator 17 to raise / lower.

[0074] Furthermore, in this embodiment, the vehicle 1 has a control unit 21 that acquires outside temperature information and vehicle speed information as vehicle information, and based on the acquired information, issues an upward / downward command to the actuator 17. Therefore, if the outside temperature T is lower than the outside temperature threshold Ts (step S1: YES), and there is a concern about the road surface freezing or freezing of the under cover or drive unit, the under cover 12 is not lowered (it remains in the retracted state) even if the vehicle speed V is equal to or greater than the vehicle speed threshold Vs. Also, if the vehicle speed V is slower than the vehicle speed threshold Vs, it is estimated that the vehicle is driving in an urban area, so the under cover 12 is not lowered (it remains in the retracted state). As a result, in the vehicle 1, when the outside temperature T is lower than the outside temperature threshold Ts, or when the vehicle speed V is lower than the vehicle speed threshold Vs, the under cover 12 is kept in the retracted state, thereby suppressing deformation and damage to the under cover 12 and its surrounding parts.

[0075] On the other hand, if vehicle 1 is determined to have an outside temperature T of or greater than the outside temperature threshold Ts and a vehicle speed V of or greater than the vehicle speed threshold Vs (under the condition that both step S1 and step S2 are NO), then the under cover 12 is deployed because the above-mentioned freezing and urban driving conditions are not expected. This reduces the loss of kinetic energy.

[0076] Furthermore, in the vehicle 1 according to this embodiment, a reference map in which an outside temperature threshold Ts and a vehicle speed threshold Vs are defined is pre-stored in the reference map storage unit 211 of the control unit 21. Therefore, the control unit 21 can acquire outside temperature information and vehicle speed information and determine whether the under cover 12 is rising or falling based on this information and the reference map.

[0077] Furthermore, since the vehicle 1 according to this embodiment is equipped with a drive unit having an actuator 17 and a link mechanism 16, it is possible to reduce manufacturing costs without employing a special structure for raising / lowering the under cover 12.

[0078] Furthermore, in vehicle 1, since the actuator 17 is fixed to the perimeter frame 18, the height positions of the under cover 12 when raised and lowered relative to the underside of vehicle 1 can be reliably defined. That is, since the perimeter frame 18 does not move up and down relative to the structural members of the vehicle body, fixing the actuator 17 to the perimeter frame 18 is suitable for defining the reference position of the under cover 12 when vibrations are added during driving.

[0079] Furthermore, since the perimeter frame 18 is located at the front of the vehicle 1 and close to the area where the under cover 12 is to be installed, there is no need to interpose a long bracket or the like to fix the actuator 17. Therefore, the actuator 17 can be securely fixed to the vehicle body.

[0080] As described above, the vehicle 1 according to this embodiment can reduce the loss of kinetic energy during driving by suppressing deformation or damage to the under cover 12 and its surrounding parts during driving by raising the under cover 12, and by suppressing the generation of vortices near the front end 11a of the front wheel 11 by lowering the under cover 12 under possible conditions.

[0081] [Differentiation] In the vehicle 1 according to the above embodiment, the rear edge 12e of the under cover 12 is positioned in front of the front wheel 11, but the present invention is not limited thereto. For example, the under cover 12 may be positioned such that the rear edge 12e is located around the axle of the front wheel 11 in the longitudinal direction.

[0082] Furthermore, although the vehicle 1 according to the above embodiment has a front portion 12a of the under cover 12 that is formed of a curved surface, the present invention is not limited thereto. The under cover 12 may have a front portion formed of a flat slope leading to a bottom surface, as long as the air flowing under the front of the vehicle 1 is guided to the rear portion 12b of the under cover 12 without separation. Also, the under cover 12 does not necessarily have to have a front portion 12a.

[0083] Furthermore, in the above embodiment of the vehicle 1, the control unit 21 acquires outside temperature information and vehicle speed information as vehicle information and decides whether to keep the under cover 12 in the retracted state or in the deployed state based on this information. However, the present invention is not limited to this. For example, navigation information may be acquired instead of vehicle speed information. This makes it possible to determine whether to raise or lower the under cover 12 based on the road surface conditions that have been registered in advance as navigation information.

[0084] Furthermore, a system (for example, a laser measuring instrument) that monitors the road surface conditions in front of vehicle 1 can be used as a basis for judging the road surface conditions.

[0085] Furthermore, the vehicle according to the present invention does not necessarily have to be equipped with a control unit 21. Specifically, the under cover 12 may be raised or lowered by the driver of the vehicle 1 in response to the environment of the road surface and the route on which the driver intends to travel.

[0086] Furthermore, while the vehicle 1 according to the above embodiment employs a structure in which the actuator 17 is fixed to the perimeter frame 18, the present invention also allows the actuator 17 to be fixed to other parts. For example, the actuator 17 can be fixed to the front side member or the front cross member. [Explanation of Symbols]

[0087] 1 vehicle 11 Front Wheel 11a Front end 12 Undercover 12b Rear (bottom flat section) 13 Front Bumper 17 Actuators 18 Perimeter Frame 19. Outdoor temperature measurement unit 20. Vehicle speed measurement unit 21 Control Unit 211 Reference map storage unit

Claims

1. At the front of the vehicle, a pair of front wheels are positioned at both ends in the width direction of the vehicle, An under cover is provided in front of the pair of left and right front wheels in the longitudinal direction of the vehicle, and between the pair of left and right front wheels in the width direction of the vehicle, and covers the bottom surface of the vehicle body. The drive unit that moves the under cover up and down, Equipped with, When the under cover is in the deployed state lowered by the drive unit, the portion in front of the rear edge has a bottom flat portion where the bottom surface is parallel to the road surface. vehicle.

2. The vehicle further comprises a front bumper positioned in front of the aforementioned pair of left and right front wheels, and extending in the width direction at the front end of the vehicle. The under cover further has a front portion that is continuous with the front end of the bottom flat portion and extends to the vicinity of the front end of the front bumper, The front portion of the under cover is composed of a smooth curved surface such that the bottom surface gradually displaces upward from the point of continuity with the bottom flat portion towards the vicinity of the front end of the front bumper. The vehicle according to claim 1.

3. The system further includes a control unit that acquires vehicle information of the vehicle and issues a command to the drive unit to raise or lower the under cover based on the acquired vehicle information. The vehicle according to claim 1 or claim 2.

4. An ambient temperature measuring unit that measures the ambient temperature, A vehicle speed measuring unit for measuring the vehicle's speed, Furthermore, The control unit acquires the outside temperature information input from the outside temperature measurement unit and the vehicle speed information input from the vehicle speed measurement unit as the vehicle information. The vehicle according to claim 3.

5. The control unit includes a reference map storage unit that pre-stores a reference map in which an outside temperature threshold and a vehicle speed threshold are defined as thresholds for raising / lowering the under cover. The vehicle according to claim 4.

6. The control unit, when it determines from the outside temperature information that the outside temperature is equal to or greater than the outside temperature threshold, and from the vehicle speed information that the vehicle speed is equal to or greater than the vehicle speed threshold, issues a command to the drive unit to lower the under cover. The vehicle according to claim 5.

7. The aforementioned drive unit is An actuator fixed to the perimeter frame, A link mechanism connecting the actuator and the under cover, Equipped with, The vehicle according to claim 1 or claim 2.

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