Lower body structure

Abstract

To raise air velocity of airflow flowing from a front side of an engine room along a top face of an undercover and deflected upward at a guide.SOLUTION: A guide 33 continuously extending upward from a top face of an undercover 3 comprises: a left-front wall part 331 linearly extending from left-front to right-rear in a plan view; a right-front wall part 332 which is positioned at a right side relative to the left-front wall part in a vehicle width direction, linearly extending from right-front to left-rear in the plan view; and a rear wall part 333 which is respectively connected to a rear end of the left-front wall part 331 and a rear end of the right-front wall part 332 in a vehicle longitudinal direction. The guide 33 is constructed in which at least one part of the rear wall part 333 linearly extends in a vehicle crosswise direction in the plan view. Thereby, airflow flowing over a wide range from a front side of an engine room 2 along the top face of the undercover 3 is aggregated into the rear wall part 333 to raise air velocity and deflect upward so as to be capable of blowing airflow whose air velocity has enough cooling performance.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This invention relates to a lower body structure having an under cover that covers the lower part of an engine room of an automobile.

Background Art

[0002] Generally, in the engine room at the front of an automobile, an under cover that covers the lower part of the engine room and has a basically smooth lower surface is provided to prevent the intrusion of water and mud and to reduce the air resistance generated under the automobile.

[0003] When the lower part of the engine room is covered with an under cover, the running wind flowing into the engine room may not reach sufficiently behind the engine, and the heat resistance of the components located near the exhaust pipe behind the engine may become a problem. As a countermeasure, it is useful to guide the air at a relatively low temperature below the engine room to the cooling-required part above in order to dissipate the heat of such cooling-required parts.

[0004] For example, Patent Document 1 discloses an opening provided in an under cover and a slope-shaped guide provided behind the opening and extending rearward and upward. With this configuration, the running wind entering the engine room from the opening climbs the guide and is guided above the engine room. As a result, it is possible to guide the cooling wind at a relatively low temperature and high wind speed to the cooling-required part above the engine room and dissipate the heat.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, if an opening is provided in the underbody cover as in Patent Document 1, the air velocity that can be delivered to the parts that need cooling is sufficient, but the airflow becomes turbulent near the opening, increasing the air resistance acting on the underside of the vehicle. Therefore, it is conceivable to utilize the airflow that passes through the front grille and radiator, enters the engine compartment, and flows rearward between the engine and other powertrain components and the underbody cover as cooling air, without providing an opening in the underbody cover. However, the air velocity of such airflow is small compared to the airflow while driving, so it is not possible to sufficiently dissipate heat in the parts that need cooling, and therefore it is necessary to increase the air velocity with a guide. The shape of the guide in Patent Document 1 is uniform in the width direction of the vehicle, so it only deflects the airflow that flows uniformly from the front in the width direction of the vehicle upward, and is not possible to increase the air velocity in the parts that need cooling. Therefore, there is room for improvement in the guide provided in the underbody cover. [Means for solving the problem]

[0007] In view of the above problems, the inventors of this invention investigated measures to increase the airflow velocity in the area requiring cooling of the airflow from the front that is deflected upward in the guide of the under cover. As a result, instead of deflecting the airflow uniformly upward in the vehicle width direction as in Patent Document 1, they found a measure to increase the airflow velocity in the area requiring cooling by concentrating the airflow flowing from the front in the center in the vehicle width direction and then deflecting it upward.

[0008] This invention, which embodies this strategy, is based on a vehicle underbody structure consisting of an under cover that forms the lower surface of the engine compartment. The under cover extends continuously upward from its upper surface. , guiding the airflow that flows from the front of the engine compartment along the upper surface of the under cover The vehicle has a guide. The guide consists of a left front wall portion that extends linearly from the front left to the rear right in a plan view, a right front wall portion that is located to the right of the left front wall portion in the vehicle width direction and extends linearly from the front right to the rear left in a plan view, and a rear wall portion that is continuous with the rear ends of the left front wall portion and the right front wall portion in the vehicle longitudinal direction. The guide is configured such that at least a portion of the rear wall portion extends linearly in the vehicle lateral direction in a plan view.

[0009] In this configuration, of the airflow that reaches the flow guide along the top surface of the under cover from the front of the engine compartment, the airflow on the left is guided by the left front wall to the rear wall located to the right rear. The airflow on the right is guided by the right front wall to the rear wall located to the left rear. Meanwhile, the airflow flowing through the center reaches the rear wall directly. As a result, most of the airflow that hits the guide is concentrated at the rear wall. Since the rear wall extends in a straight line in the left-right direction of the vehicle, the concentrated airflow does not flow behind the rear wall but is deflected upward. Therefore, by concentrating the airflow over a wide area on the rear wall, increasing the airflow velocity, and deflecting it upwards, it is possible to deliver an airflow with sufficient velocity to the area requiring cooling.

[0010] In this invention, in a plan view, the rear wall portion is ...from the straight-extending portion of the rear wall, it bends diagonally in the vehicle's front-rear direction and left-right direction. It consists of at least one bent section and a plurality of small wall sections continuous in the bent section, wherein the small wall section located furthest rear in the vehicle's longitudinal direction extends linearly in the vehicle's lateral direction. like composition It is being done .

[0011] In this configuration, a portion of the airflow directed to the rear wall, excluding the small wall located at the very rear, reaches that small wall. As a result, the airflow rate reaching that small wall increases, further increasing the airflow velocity of the airflow that is deflected upward there and blown to the area requiring cooling.

[0012] In this invention, the rear wall portion is 、 In a plan view, they extend in a straight line in the left-right direction of the vehicle and are positioned apart from each other. As the aforementioned small wall portion The structure may also have a first rear wall section and a second rear wall section.

[0013] With this configuration, the airflow directed to the rear wall is concentrated at the first and second rear wall sections, increasing the airflow velocity and deflecting it upwards, thereby enabling a sufficient airflow velocity to be delivered to cooling areas located at different positions in the vehicle width direction.

[0014] The first rear wall section and the second rear wall section may be positioned at different locations in the longitudinal direction of the vehicle.

[0015] With this configuration, the airflow directed to the rear wall is concentrated at the first and second rear wall sections, increasing the airflow velocity and deflecting it upwards, thereby enabling the delivery of a sufficient airflow velocity to cooling areas located at different positions in the front-to-back direction.

[0016] In a plan view, between the first rear wall section and the second rear wall section of the rear wall section, extending in the longitudinal and lateral directions of the vehicle. As the aforementioned small wall portion It may have a third rear wall portion.

[0017] This configuration increases the amount of air flowing into the first or second rear wall behind the third rear wall, and increases the wind speed of the airflow deflected upward there. Therefore, it is suitable when the part requiring cooling is located above the first or second rear wall.

[0018] The present invention further includes an auxiliary guide attached to the rear of the powertrain, the auxiliary guide including a rear plate portion that extends linearly in the left-right direction of the vehicle at a distance from the powertrain in a plan view, the rear plate portion being located between the front and rear ends of the guide in the longitudinal direction of the vehicle, and at least a portion of the rear plate portion being located between the right and left ends of the guide in the left-right direction of the vehicle.

[0019] This configuration allows the airflow deflected upward by the guide to be further directed upward along the auxiliary guide. It is particularly suitable when there is a vertical distance between the part requiring cooling and the guide.

[0020] In this invention, the rear wall portion extends linearly in the left-right direction of the vehicle in a plan view and is positioned apart from each other. As the aforementioned small wall portion It has a first rear wall section and a second rear wall section, and further has an auxiliary guide attached to the rear of the powertrain, the auxiliary guide includes a rear plate section that extends linearly in the left-right direction of the vehicle at a distance from the powertrain in a plan view, and the rear plate section is the first rear wall section in the front-rear direction of the vehicle Behind and The second rear wall portion forward It is located in the left-right direction of the vehicle, and at least a portion of the rear panel is located in the left-right direction of the vehicle. handIt may be configured to be located between the right end and the left end of the first rear wall portion or the second rear wall portion.

[0021] According to this configuration, a part of the air flow deflected upward by the rear wall portion can be further guided upward along the auxiliary guide. This is particularly suitable when there is a distance in the vertical direction between the portion that needs to be cooled and the rear wall portion.

[0022] Furthermore, the auxiliary guide may be disposed below the exhaust pipe of the power train.

[0023] According to this configuration, it is suitable when there is a portion that needs to be cooled in the vicinity of the exhaust pipe which is a high-temperature member.

[0024] When the auxiliary guide is disposed below the exhaust pipe, the front opening of the engine room is further provided at the center of the vehicle In the vehicle width direction and a drive shaft boot is disposed at a position between the exhaust pipe and the auxiliary guide in the vertical direction and overlapping the exhaust pipe in the vehicle left-right direction. It is also possible to configure such that the auxiliary guide is located between the inner end in the vehicle width direction of the drive shaft boot and the center in the vehicle width direction of the engine room.

[0025] According to this configuration, the running wind enters the engine room from the front opening provided at the center of the vehicle. The air flow flows rearward between the power train and the under cover. Since the width in the vehicle width direction of the flow path is larger than the width of the front opening, a velocity component toward the outside in the vehicle width direction is generated in the air flow. The velocity component toward the outside is maintained even when the air flow is deflected upward by the guide and further guided upward to the position where the drive shaft boot is located by the auxiliary guide. Since the drive shaft boot is configured to be located outside the auxiliary guide in the vehicle width direction, the air flow can be guided to the space between the exhaust pipe and the drive shaft boot, and the drive shaft boot can be effectively cooled.

Brief Description of the Drawings

[0026] [Figure 1] It is a perspective view of an automobile to which the present invention is applied. [Figure 2] This is a bottom view of an automobile to which the present invention is applied. [Figure 3] This is a partially fractured side view, including the section taken along line III-III in Figure 2. [Figure 4] This is an undercover perspective. [Figure 5] This is a cross-sectional view of the undercover in the direction of the VV line in Figure 4. [Figure 6] This is a view of the underbody cover guide from above the vehicle. [Figure 7] This diagram shows the underbody cover and the drive shaft and exhaust pipe above it. [Figure 8] This is a view of the underbody cover and auxiliary guide area from the left rear. [Figure 9] This is a rear view of the area around the under cover and auxiliary guide. [Figure 10] This is a view of the area around the undercover and auxiliary guide from the lower right. [Figure 11] This is a perspective view of the supplementary guide. [Figure 12] This is a cross-sectional view taken along the line AA in Figure 7, showing the inside of the engine compartment. [Figure 13] This is a cross-sectional view taken along the BB arrow in Figure 7, showing the inside of the engine compartment. [Figure 14] Figure 12 is a schematic diagram showing the airflow in a cross-section. [Figure 15] Figure 13 is a schematic diagram showing the airflow in a cross-section. [Figure 16] This is a schematic diagram showing the airflow along the top surface of the underbody cover. [Modes for carrying out the invention]

[0027] The following describes the underbody structure of an embodiment of the present invention with reference to the drawings. Note that the form described below is one aspect of the present invention, and the present invention is not limited to the following form except for its essential configuration.

[0028] The engine compartment 2 located at the front of the automobile 1 shown in Figure 1 is, as is well known, a space defined by the hood, body panels, and the under cover 3, which will be described later. At the front of this compartment is a front opening 21 located in the center of the fan cowl in the width direction of the vehicle, which is positioned behind the radiator, and which houses the radiator fan. When the automobile 1 is in motion, most of the airflow in the engine compartment 2 flows in through the front opening 21.

[0029] As shown in Figure 2, the underside of the engine compartment 2 is defined by the under cover 3. The underside of the under cover 3 has a smooth shape to reduce air resistance generated beneath the vehicle 1. The under cover 3 is fastened directly or via brackets to the frame members that support the suspension and engine between the left and right front wheels 4.

[0030] Inside the engine compartment 2, as shown in Figure 3, are the powertrain 5, which includes the engine, and the exhaust system 6. Behind the powertrain 5 and below the exhaust system 6, is the drive shaft 7, which transmits the rotational output of the powertrain 5 to the front wheels 4. The under cover 3 is located at the very bottom of the engine compartment, below the powertrain 5.

[0031] The under cover 3 is a resin part in which a plate-shaped portion 31, a reinforcing frame 32, and a guide 33 are integrally molded. The plate-shaped portion 31 has a thickness of approximately 2 mm and consists of a front plate-shaped portion 31b that extends upward toward the front of the vehicle from the bent portion 31a, and a rear plate-shaped portion 3c that extends horizontally toward the rear of the vehicle from the bent portion 31a.

[0032] As shown in Figure 4, a reinforcing frame 32 is provided on the upper surface of the under cover 3 to ensure rigidity. The reinforcing frame 32 is approximately 4 mm high from the upper surface of the plate-like portion 31 and has a plate thickness of approximately 1.5 mm. In a plan view, it consists of five longitudinal ribs 32a extending in the vehicle's front-rear direction, five transverse ribs 32b extending in the vehicle's left-right direction, and two diagonal ribs 32c extending diagonally.

[0033] As shown in Figure 5, the guide 33 extends vertically upward from the upper surface of the plate-like portion 31. The thickness of the guide 33 is approximately 1.5 mm, the same as that of the reinforcing frame 32. On the other hand, the height of the guide 33 from the upper surface of the plate-like portion 31 is greater than that of the reinforcing frame 32, at approximately 35 mm.

[0034] As shown in Figure 6, the guide 33 consists of a left front wall portion 331 on the left side in the vehicle width direction, a right front wall portion 332 on the right side in the vehicle width direction, and a rear wall portion 333 located between the two front wall portions 331 and 332. In a plan view, the left front wall portion 331 extends linearly to the left and forward from the left end of the rear wall portion 333, and the right front wall portion 332 extends linearly to the right and forward from the right end of the rear wall portion 333.

[0035] The rear wall section 333 consists of three small wall sections and two bent sections. The three small wall sections are the first rear wall section 333a, the second rear wall section 333b, and the third rear wall section 333c. The leftmost first rear wall section 333a extends linearly in the left-right direction of the vehicle. The rightmost second rear wall section 333b extends linearly in the left-right direction of the vehicle, further rearward than the first rear wall section 333a. The third rear wall section 333c extends linearly to the left and forward from the left end of the second rear wall section 333b toward the right end of the first rear wall section 333a, specifically at a 45-degree angle to the left with respect to the front-rear direction of the vehicle.

[0036] Therefore, the first rear wall portion 333a and the second rear wall portion 333b, which both extend linearly in the left-right direction of the vehicle, are located apart from each other. Furthermore, the first rear wall portion 333a is located further forward than the second rear wall portion 333b in the front-rear direction of the vehicle.

[0037] As shown in Figures 7 to 11, a sheet metal auxiliary guide 8 is positioned at the rear of the lower part of the engine block 51 of the powertrain 5. As shown in Figure 8, the oil pan 52 is fastened to the engine block 51 from below, the front cover 53 is fastened to the left, and the drive shaft 7 support bracket 71 is fastened to the rear. The auxiliary guide 8 is then fastened to the front cover 53 and the support bracket 71.

[0038] As shown in Figure 11, the auxiliary guide 8 extends vertically and consists of a rear plate portion 81, a left plate portion 82, and a right plate portion 83. The rear plate portion 81 extends in the left-right direction of the vehicle, while the left plate portion 82 and the right plate portion 83 extend forward from the left and right ends of the rear plate portion 81, respectively.

[0039] The left plate portion 82 and the right plate portion 83 of the auxiliary guide 8 are each provided with a left flange portion 82a and a right flange portion 83a that extend in the left-right direction. The left flange portion 82a is fastened to the lower part of the front cover 53, and the right flange portion 83a is fastened to the lower part of the support bracket 71 of the drive shaft 7.

[0040] The rear plate portion 81 is located behind the first rear wall portion 333a of the guide 33 in the vehicle's longitudinal direction, and to the left of the third rear wall portion 333c and straddling the left front wall portion 331 and the first rear wall portion 333a in the vehicle's lateral direction.

[0041] As shown in Figures 7 and 13, the auxiliary guide 8 is positioned below the exhaust pipe 61, which forms part of the exhaust system 6, whether viewed from the side or the rear of the vehicle. The exhaust pipe 61 extends diagonally backward from the left side of the engine toward the rear center.

[0042] The drive shaft boot 72, which covers the right end of the drive shaft 7, is located below the exhaust pipe 61 and above the auxiliary guide 8. The drive shaft boot 72 is located below the exhaust pipe 61. On the other hand, the drive shaft boot 72 is located to the left of the auxiliary guide 8. Specifically, as shown in Figure 9, the left plate portion 82 of the auxiliary guide 8 is located in the same position in the left-right direction of the vehicle as the right end 72a of the drive shaft boot 72.

[0043] Next, we will describe the path through which the airflow is guided upward from the front of the engine compartment 2 to the rear of the powertrain 5. In the vehicle width position shown in Figure 14, the airflow generated by entering the engine compartment 2 from the front opening 21 proceeds rearward along the upper surface of the under cover 3 below the powertrain 5. The airflow that reaches the second rear wall portion 333b of the guide 33 is deflected upward and flows rearward through the area below the drive shaft 7. As a result, the drive shaft 7, which receives radiant heat from the exhaust pipe 61, can be cooled.

[0044] On the other hand, at the vehicle width position shown in Figure 15, the airflow deflected upward by the first rear wall portion 333a of the guide 33 is further guided upward by the auxiliary guide 8 and flows rearward through the space between the exhaust pipe 61 and the drive shaft 7. As a result, the radiant heat received by the drive shaft 7 from the exhaust pipe 61 can be reduced.

[0045] The airflow deflected upward by the flow guide 33 along the upper surface of the under cover 3 will be described in more detail. The airflow flowing in from the front opening 21 located in the center of the vehicle in the left-right direction has a flow path width greater than the width of the front opening 21, so a velocity component is generated outward in the vehicle width direction. As shown in Figure 16, the airflow flowing to the guide 33 along the upper surface of the under cover 3 is generally directed towards the left rear of the vehicle because the guide is located to the left in the vehicle width direction relative to the vehicle opening 21. The airflow on the left front of the guide 33 is guided by the left front wall 331 to the rear right wall 333, and the airflow on the right front is guided by the right front wall 332 to the rear left wall 333. The airflow flowing through the center then reaches the rear wall 333. As a result, the airflow flowing along the upper surface of the under cover 3 is concentrated at the rear wall 333 and deflected upward. The deflected airflow then passes behind the oil pan 52, between the drive shaft 7 and the exhaust pipe 61, and flows to the rear of the engine compartment 2.

[0046] Next, the airflow guided by the auxiliary guide 8 will be explained in detail. As shown in Figure 15, the airflow that flows along the upper surface of the under cover 3 and towards the left rear of the vehicle reaches the first rear wall 333a located on the left. Then, as shown in Figure 16, it is deflected upward by the first rear wall 333a and flows upward between the oil pan 52 and the auxiliary guide 8. As a result, there is a velocity component to the left, so it flows to the rear of the engine compartment 2, passing between the drive shaft boot 72 and the exhaust pipe 61, which are located to the left of the auxiliary guide 8 in the vehicle width direction. [Explanation of symbols]

[0047] 1. Automobile 2. Engine Room 21...Front opening 3. Undercover 31. Plate-like part 32. Reinforcement frame 32a... Longitudinal ribs, 32b... Transverse ribs 33... Guide 331...Left front wall 332...right front wall 333...Rear wall section 333a...First rear wall part, 333b...Second rear wall part, 333c...Third rear wall part 4. Front wheel 5. Powertrain 51. Engine Block 52... Oil pan 53... Front cover 6. Exhaust System 61... Exhaust pipe 7. Drive shaft 71...Support bracket 72... Drive shaft boots 8. Supplementary Guide 81...Rear plate part 82...Left plate part 83...Right panel 82a...Left flange section, 83a...Right flange section

Claims

1. In the underbody structure of a vehicle, where the underside of the engine compartment is formed by an under cover, The under cover has a guide that extends continuously upward from its upper surface and guides the airflow that flows from the front of the engine compartment along the upper surface of the under cover, The guide has a left front wall portion that extends linearly from the front left to the rear right in a plan view, The right front wall section is located to the right of the left front wall section in the vehicle width direction and extends in a straight line from the front right to the rear left in a plan view, It consists of the left front wall portion and the right front wall portion, each of which is continuous with the rear end in the vehicle's longitudinal direction, At least a portion of the rear wall extends in a straight line in the left-right direction of the vehicle when viewed from above. In a plan view, the rear wall portion consists of at least one bent portion that bends diagonally in the vehicle's longitudinal direction and lateral direction from a linearly extending portion of the rear wall portion, and a plurality of small wall portions that are continuous at the bent portion. The characteristic feature is that the small wall section located furthest rear in the vehicle's longitudinal direction extends in a straight line in the vehicle's lateral direction. Underbody structure of the vehicle.

2. The rear wall portion is characterized by having a first rear wall portion and a second rear wall portion, which are small wall portions, that extend linearly in the left-right direction of the vehicle in a plan view and are located apart from each other. The underbody structure of a vehicle according to claim 1.

3. The first rear wall portion and the second rear wall portion are characterized by being positioned at different locations in the vehicle's longitudinal direction. The underbody structure of the vehicle according to claim 2.

4. The rear wall portion is characterized in that, in a plan view, it has a third rear wall portion as a small wall portion that extends in the vehicle's longitudinal direction and vehicle's left-right direction between the first rear wall portion and the second rear wall portion. The underbody structure of a vehicle according to claim 2 or 3.

5. It has a plate-shaped auxiliary guide that extends vertically in the vehicle and is attached to the rear of the powertrain, The auxiliary guide includes a rear plate portion that extends linearly in the left-right direction of the vehicle, spaced apart from the powertrain in a plan view. The rear plate portion is located between the front and rear ends of the guide in the longitudinal direction of the vehicle. The rear plate portion is characterized by being located between the right end and the left end of the guide in the left-right direction of the vehicle. The underbody structure of a vehicle according to any one of claims 1 to 4.

6. It has a plate-shaped auxiliary guide that extends vertically in the vehicle and is attached to the rear of the powertrain, The auxiliary guide includes a rear plate portion that extends linearly in the left-right direction of the vehicle, spaced apart from the powertrain in a plan view. The rear plate portion is located behind the first rear wall portion and in front of the second rear wall portion in the longitudinal direction of the vehicle. At least a portion of the rear panel is located between the right and left ends of the first rear wall or the second rear wall in the left-right direction of the vehicle. The underbody structure of a vehicle according to any one of claims 2 to 4.

7. The underbody structure of the vehicle according to claim 5 or 6, characterized in that the auxiliary guide is positioned below the exhaust pipe of the powertrain.

8. The front opening of the engine compartment is located at the center in the vehicle's width direction. The drive shaft boot is positioned between the exhaust pipe and the auxiliary guide in the vertical direction, and overlaps with the exhaust pipe in the vehicle's left-right direction. The auxiliary guide is characterized in that it is positioned between the inner end of the drive shaft boot in the vehicle width direction and the center of the engine compartment in the vehicle width direction. The underbody structure of a vehicle according to claim 7.

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