JP2018165118A - Lower vehicle body structure of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lower vehicle body structure of a vehicle which cools an engine room and a device disposed behind the engine room and needing cooling more effectively while inhibiting interference between air discharged from the engine room side to the vehicle body lower side and travel wind flowing from an area below a bumper on a vehicle front surface along a road surface.SOLUTION: In a lower vehicle body structure, a device 35 needing cooling is disposed behind an engine room of a vehicle and an undercover 40 covering the device 35 from below is provided. In the undercover 40, an air intake part 41 is provided at the front side relative to the device 35. The air intake part has: a step part in which the rear side is located lower than the front side; a wind guide part which is located behind the step part and inclines upward from the front side to the rear side; and an opening which is located behind the wind guide part and opens upward in the undercover 40. The wind guide part extends its width to left and right sides from the vehicle body front side to the rear side, and a rear end part of the opening is formed at the vehicle body rear side relative to a rear end part of the wind guide part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lower body structure of a vehicle having an under cover that covers a lower portion of the vehicle, and belongs to the technical field of a vehicle body structure of a vehicle such as an automobile.

  Normally, air that flows into the engine room from a radiator grille in front of the vehicle during vehicle travel passes through a cooling device (condenser, radiator, etc.) disposed behind the bumper and flows toward the rear of the vehicle body. And this air is discharged | emitted below a vehicle body along the exhaust pipe etc. which are arrange | positioned behind a dash panel and an engine room. In this case, the air discharged below the vehicle body described above and the traveling wind that flows in from below the bumper on the front of the vehicle and flows along the road surface interfere with each other below the rear of the engine room, and the air flow below the floor of the vehicle Will be disturbed. As a result, there is a possibility that the air resistance of the vehicle is increased and the fuel efficiency is deteriorated.

  In response to this, the air exhausted downward from the engine room is covered with an under cover to cover the lower part of the rear part of the engine room. In some cases, measures have been taken to avoid interference between the two by partitioning the traveling wind that flows in from below and flows along the road surface.

  By the way, equipment that needs to be cooled, for example, a catalyst that constitutes an exhaust system of the engine (hereinafter referred to as “cooling required equipment”) is disposed in the engine room and in the lower part of the floor behind the engine room. And normally, the said cooling required apparatus is cooled by the driving | running | working wind along the road surface generated with driving | running | working of a vehicle, However, When providing the above-mentioned undercover, the said driving | running | working wind is taken in as a cooling wind. This makes it impossible to cool the equipment requiring cooling. For this reason, the cooling of the cooling-required equipment disposed above the under cover while partitioning the air discharged from the engine room side below the vehicle body and the traveling wind flowing from below the bumper in front of the vehicle and flowing along the road surface It was necessary to ensure performance.

  With regard to this problem, in the lower vehicle body structure of the vehicle described in Patent Document 1, an air guide portion having an inclined surface and an opening opening on the upper surface side of the under cover at the rear end is provided on the under cover that covers the lower portion of the engine room. Is provided. Thereby, by separating the air and the traveling wind as described above, the interference between the two is avoided, and the traveling wind is guided from the air guide portion to the upper portion of the under cover, thereby being disposed above the under cover. The cooling of the required cooling equipment is being achieved.

JP 2013-139178 A

  However, the air guide portion of the under cover described in Patent Document 1 simply has a structure in which an air guide portion having an inclined surface and an opening opening on the upper surface side of the under cover at the rear end is provided in the under cover. Therefore, there may be a case where a sufficient amount of traveling wind cannot be introduced for cooling the equipment requiring cooling. For example, in the case of a high load condition such as uphill traveling where the amount of heat generated by the required cooling device increases, the cooling is insufficient with respect to the heat generated by the required cooling device. In particular, when the equipment requiring cooling is disposed at a position where heat accumulation is likely to occur, such as the tunnel part in the center of the vehicle body floor, measures such as taking in more running air for cooling the equipment requiring cooling are taken. Necessary.

  Therefore, the present invention suppresses the interference between the air discharged from the engine compartment side during traveling and the traveling wind flowing in along the road surface from the lower side of the bumper in front of the vehicle, It is an object of the present invention to achieve both the improvement of the aerodynamic performance of the vehicle and the cooling of the required cooling device by cooling the required cooling device disposed on the rear side more effectively.

  In order to solve the above-mentioned problems, the lower body structure of a vehicle according to the present invention is configured as follows.

First, the invention according to claim 1 of the present application is
Equipment that needs cooling is deployed at the rear of the engine room, and
In the lower vehicle body structure of the vehicle provided with an under cover that covers the device and the lower part of the opening at the rear of the engine room,
The under cover is provided with an air intake portion on the front side of the device,
The air intake portion includes a step portion whose rear side is lower than the front side, a wind guide portion inclined upward from the front toward the rear behind the step portion, and an under cover from the rear end of the wind guide portion to the rear. An opening that opens upward,
The wind guide portion is formed to widen from the front to the rear of the vehicle body on both the left and right sides,
The opening is characterized in that the rear end of the opening is formed on the rear side of the vehicle body with respect to the rear end of the air guide portion.

  Here, the “rear part of the engine room” as referred to in claim 1 indicates a part or all of the region from the rear part in the engine room to the rear part of the engine room following the part. .

The invention according to claim 2 is the invention according to claim 1,
The wind guide portion of the under cover is formed by raising a planar basic surface portion upward,
The wind guide portion is formed of a downwardly convex curved portion that is continuous from the basic surface portion in a side view, and the curvature radius of the curved portion is 100 mm or more.

The invention according to claim 3 is the invention according to claim 1 or 2,
The opening of the air intake portion in the under cover is provided in front of the vehicle body from the lower end portion of the dash panel that partitions the engine room and the vehicle interior of the vehicle body.

  According to the first aspect of the present invention, the lower body structure of the vehicle has the air intake portion provided at the front portion of the vehicle body of the under cover that covers the lower surface of the vehicle body, and the opening portion provided at the rear thereof. Is provided. The wind guide portion is provided so as to be inclined from the front to the rear, and the opening provided at the rear of the wind guide portion is opened above the under cover, so that the vehicle A traveling wind that flows in from below the front bumper and flows along the road surface is guided to the opening of the air intake along the air guide portion of the air intake, above the under cover, and It will flow into the space near the equipment that needs cooling, such as a catalyst, arranged behind the opening. And since the said driving | running | working wind is sufficiently low temperature compared with the air which flows in from an engine room side, the said apparatus will be cooled.

  As a result, the under cover separates the air discharged from the engine room side below the vehicle body and the traveling wind flowing from below the bumper in front of the vehicle and flowing along the road surface. It is possible to effectively cool the engine room and the device arranged behind the engine room while suppressing disturbance of the air flow below the vehicle body.

  And since the step part of the air intake part is formed lower in the rear than the front of the under cover, the air flow is increased while the flow velocity is increased at the step part of the air intake part. Along the under cover.

  Furthermore, since the air guide part of the air intake part is formed so as to widen on both the left and right sides from the front to the rear, the side flow at the left and right ends of the air guide part of the air intake part is The flow velocity is lower than that of the main flow flowing through the central portion of the portion, and both end portions of the air guide portion become negative pressure. As a result, the traveling wind is drawn upward of the under cover, and the flow at the center of the air guide portion can be more effectively accelerated. As a result, the traveling air can be taken in more positively as the cooling air for the equipment that needs to be cooled.

  In addition, since the rear end portion of the opening of the air intake portion is formed to be behind the vehicle body from the rear end portion of the air guide portion, for example, the rear end portion of the opening portion and the guide Compared to the case where the rear end portion of the wind portion overlaps in plan view, a larger flow path for taking in the traveling wind above the under cover is secured, and the flow rate of the traveling wind is more reliably secured. And the effect of cooling the device is improved.

  According to the second aspect of the present invention, the air guide portion of the under cover is formed by raising a planar basic surface portion upward, and the air guide portion is formed from the basic surface portion in a side view. A continuous downward convex curved portion is formed, and the radius of curvature of the curved portion is 100 mm or more, so that the traveling wind flowing along the road surface flows from below the bumper on the front of the vehicle at the normal speed. Since it can be pulled in above the under cover without being peeled along the shape of the curved portion of the under cover, the flow rate of the traveling wind as the cooling air to be guided can be ensured more reliably.

  According to a third aspect of the present invention, the under cover is provided with an opening of the air intake portion in front of the vehicle body rather than a lower end portion of a dash panel that partitions the engine room and the vehicle interior of the vehicle body. Thus, it is possible to prevent the flow of air that flows into the rear of the engine room and goes downward along the shape of the dash panel from flowing into the opening of the air intake portion. As a result, when the traveling wind that flows from the lower side of the bumper in front of the vehicle and flows along the road surface is guided to the upper side of the under cover from the opening of the air intake portion, It is prevented from being obstructed by the air flowing into. As a result, the flow rate and flow velocity of the cooling air for cooling the equipment that needs to be cooled are ensured, and the equipment can be cooled more effectively.

It is a bottom view which shows the lower vehicle body structure of the vehicle which concerns on embodiment of this invention. It is AA sectional drawing in FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a single figure of the tunnel undercover concerning the embodiment of the present invention. (A) The principal part expansion perspective view of a tunnel undercover, (b) It is BB sectional drawing in FIG. It is operation | movement explanatory drawing of the tunnel undercover single-piece | unit based on embodiment of this invention.

  Hereinafter, the details of the lower body structure of the vehicle according to the embodiment of the present invention will be described.

  As shown in FIGS. 1 to 3, a dash panel 11 is provided at a front portion of the vehicle body 1, and the dash panel 11 is disposed so as to stand up from a floor panel 12 of the passenger compartment R, and the engine room. E and compartment R are separated.

  As shown in FIG. 2, on the engine room E side, front side members 13 and 13 that extend in the longitudinal direction of the vehicle body on the left and right sides of the dash panel 11, left and right suspension towers 14 and 14, and the left and right suspension towers Apron reinforcements 15, 15 extending forward from the upper portions of 14, 14, and a front bumper constituting a front bumper 17 fixed to front ends of the left and right front side members 13, 13 via crash cans 16, 16 Reinforcement 18 is provided.

  Further, the front bumper 17 is provided with a radiator grille 17a for taking the traveling wind W generated by traveling of the vehicle as cooling air into the engine room E. Further, a condenser 21, a radiator 22, and a fan 23 that constitute a cooling device 20 for cooling engine cooling water are disposed behind the radiator grill 17a. The cooling device 20 is fixed to a shroud (not shown). The shroud has a substantially rectangular frame shape when viewed from the front, and includes the apron reinforcements 15 and 15 and a front bumper. It is fixed with respect to the reinforcement 18.

  An engine 31 and a transmission 32 are disposed behind the cooling device 20, and an exhaust pipe 34 connected to an exhaust manifold 33 constituting an exhaust system and a catalyst 35 are disposed behind the engine 31. The pre-silencer 36 and the like are arranged so as to extend in the longitudinal direction of the vehicle body.

  By the way, a pair of left and right floor frames 12a, 12a extending in the longitudinal direction of the vehicle body are disposed at the lower portion of the floor panel 12, and a pair of left and right side members 13, 13 whose front end portions extend in the longitudinal direction of the vehicle body in the engine room E. It is connected to the rear end.

  Further, at the center of the floor panel 12 in the vehicle width direction, a front end is connected to the dash panel 11 and a tunnel portion 19 protruding into the vehicle interior is formed. The tunnel portion 19 extends in the longitudinal direction of the vehicle body along the exhaust systems 33, 34, 35, and the exhaust pipe 34, the catalyst 35, the pre-silencer 36, etc. are accommodated in the recessed space of the tunnel portion 19. . A pair of left and right tunnel members 19a and 19a extending in the longitudinal direction of the vehicle along the lower edge of the tunnel portion 19, and a tunnel cross member 19b is provided at the center of the tunnel portion in the longitudinal direction of the vehicle body. .

  The lower part of the floor panel 12 and the floor frames 12a and 12a are covered with, for example, plate-like floor undercovers 12b and 12b made of a resin material. Here, the floor under covers 12b and 12b are divided into left and right at a substantially central portion in the vehicle body width direction, and in the tunnel portion 19 corresponding to the center portion in the vehicle body width direction which is not covered by the floor under covers 12b and 12b. Is covered with a tunnel under cover 40 made of a steel plate, for example. The “under cover” in the claims corresponds to the tunnel under cover 40.

  The tunnel under cover 40 has a front end portion on the suspension cross member 51, left and right end portions on the tunnel members 19a and 19a, a rear end portion on the tunnel cross member 19b, and fastening members 19c... 19c such as bolts and nuts. It is concluded.

  Here, the details of the tunnel undercover 40 will be described with reference to FIGS.

  As shown in FIGS. 3 and 4, the tunnel under cover 40 includes an air intake portion 41 that takes in a traveling wind W that flows from below the bumper 17 in front of the vehicle and flows along the road surface above the under cover 40. First and second air discharge portions 42 and 43 for discharging air W2 flowing into the tunnel portion 19 from the engine room E side of the vehicle are provided.

  First, as shown in FIGS. 4 and 5, the air intake portion 41 includes a basic surface portion 41a, left and right slope portions 41b and 41b rising upward from an end portion of the basic surface portion 41a in the vehicle body width direction, Left and right flange portions 41c and 41c extending in the vehicle body width direction from the upper ends of the left and right slope portions 41b and 41b are provided. The air intake portion 41 includes a front slope portion 41d that rises upward from an end of the basic surface portion 41a on the vehicle body front side, and a front flange portion 41e that extends in the vehicle body front direction from the upper end of the front slope portion 41d. The basic surface portion 41a, the front slope portion 41d, and the front flange portion 41e form a step portion 41f.

  The air intake portion 41 has an air guide surface portion 41g formed by raising a basic surface portion 41a continuous behind the stepped portion 41f, and the air guide surface portion 41g is upward from the front to the rear. It is a downwardly convex curved portion that inclines, and the curved portion has a gently curved surface with a radius of curvature of 100 mm or more. For example, when the curved portion is formed of a cylindrical surface, the center of the cylindrical surface is located immediately above the front end portion 41h of the air guide surface portion 41g, so that the air guide surface portion 41g and the basic surface portion 41a is continuously formed on a smoother surface. The air guide surface portion 41g is widened from the front end portion 41h to the rear end portion 41i on both the left and right sides, and has a substantially trapezoidal shape in plan view.

  The left and right end portions 41g ′ and 41g ′ of the air guide surface portion 41g and the basic surface portions 41a on both sides of the air guide surface portion 41g are connected by substantially triangular side surfaces 41j and 41j. The surface portion 41g and the side surface portions 41j and 41j form an air guide portion 41k of the air intake portion 41.

  In addition, an opening 41l extending in the vehicle body width direction is provided between the right and left slope portions 41b and 41b behind the air guide portion 41k, and a front end portion 41l ′ of the opening is provided in the guide portion 41l ′. A rear end portion 41i of the wind portion 41k is formed, and a rear end portion 41m of the opening portion 41l is disposed behind the rear end portion 41i of the air guide portion 41k.

  As shown in FIG. 3, the opening 41 m of the air intake portion 41 is provided so as to be positioned in front of the lower end portion 11 a of the dash panel 11 in the longitudinal direction of the vehicle body, and the opening 41 m. The catalyst 35 is disposed in the tunnel portion 19 behind the rear.

  Next, as shown in FIG. 3, the first and second air discharge portions 42 and 43 are disposed below the catalyst 35 and below the pre-silencer 36, respectively.

  As shown in FIG. 4, the first air discharge part 42 has a plurality of openings 42a... 42a extending in the vehicle body width direction, and is inclined downward from the front to the rear following the openings 42a. A plurality of air guide portions 42b... 42b are provided.

  The plurality of openings 42a... 42a of the first air discharge section 42 are arranged side by side in the vehicle body front-rear direction, an opening 42a that opens over the entire width, and a vehicle width direction behind the opening 42a. It is comprised by the opening part 42a ... 42a provided by being divided | segmented.

  The plurality of air guide portions 42b... 42b of the first air discharge portion 42 are formed by raising the planar basic surface portion 40a of the tunnel under cover 40, and are formed by a downward curved convex portion, The basic surface portion 40a is continuously provided with a smooth curved surface.

  Similarly to the first air discharge portion 42, the second air discharge portion 43 includes a plurality of openings 43a ... 43a extending in the vehicle body width direction, and from the front to the rear following the openings 43a ... 43a. A plurality of air guide portions 43b... 43b that are inclined downward toward the front are provided.

  The plurality of openings 43a... 43a of the second air discharge part 43 are formed to open over the entire width and are arranged side by side in the longitudinal direction of the vehicle body.

  The plurality of air guide portions 43b... 43b of the second air discharge portion 43 are formed by raising the planar basic surface portion 40a of the tunnel under cover 40, similarly to the second air discharge portion 42, and It is formed with a downwardly convex curved portion and is continuously provided with a smooth curved surface on the basic surface portion 40a.

  The present embodiment is configured as described above, and its operation will be described with reference to FIGS. 3 and 6.

  As shown in FIG. 3, when the vehicle travels, the traveling wind W that flows in from below the bumper 17 in front of the vehicle and flows along the road surface passes along the floor undercovers 12 b and 12 b and the tunnel undercover 40. It flows under the covers 12b, 12b, 40 from the front of the vehicle body to the rear.

  On the other hand, the air W1 and W2 flowing into the engine room E from the radiator grille 17a in front of the vehicle flows into the tunnel portion 19 from the engine room E along the dash panel 11 and the exhaust systems 33 and 34. The air is divided into an air W1 flowing into the upper part of the exhaust system 34, 35, 36 in the tunnel part 19 and an air W2 flowing into the lower part of the exhaust system 34, 35, 36. Then, the air W1 that has flowed into the upper part of the exhaust systems 34, 35, 36 flows in the tunnel portion 19 along the exhaust systems 34, 35, 36 to the rear of the vehicle body, and the exhaust systems 34, 35, 36 The air W <b> 2 that has flowed downward is suppressed by the tunnel under cover 40 from flowing out from below the tunnel portion 19 as indicated by a two-dot chain line W <b> 2 ′.

  In the first and second air discharge portions 42 and 43 of the tunnel under cover 40, the engine room E and the lower part of the vehicle body communicate with each other, but the first and second air discharge portions 42 and 43 are guided. Since the wind portions 42b... 42b, 43b... 43b are formed with gentle curved surfaces, the air W3 flowing below the vehicle body causes the air W2 below the exhaust systems 35 and 36 to be directed to the wind guide portions 42b. , 43b... Along the shape of 43b, the vehicle is discharged downward without peeling. Thereby, it can be made to merge smoothly with the said driving | running | working wind W, and the disturbance of the flow below the floor of a vehicle can be suppressed.

  Furthermore, in the present embodiment, the traveling wind W is taken in from the air intake portion 41 of the tunnel under cover 40 as cooling air for cooling the catalyst 35 as indicated by an arrow W ′, Therefore, the catalyst 35 can be cooled.

  At this time, since the air intake portion 41 is disposed in front of the inclined lower end portion 11 a of the dash panel 11, the air intake portion 41 flows from the engine room E side below the exhaust systems 33 and 34. Interference between the air W2 to be performed and the cooling air W ′ taken in from the air intake portion 41 is prevented.

  Specifically, as shown in FIG. 6A, in the air intake portion 41 of the tunnel undercover 40, the traveling wind W is stepped 41f of the air intake portion 41 as indicated by an arrow W ′. While the flow velocity is increased by the above, the air flows into the tunnel portion 19 from the opening portion 41l behind the air guide portion 41k through the air guide portion 41k behind the step portion 41f.

  Further, the rear end portion 41m of the opening 41l of the air intake portion 41 is formed so as to be behind the vehicle body from the rear end portion 41i of the air guide portion 41k. Compared to the case where the end portion 41m and the rear end portion 41i of the air guide portion 41k overlap in plan view, the traveling wind W is indicated by an arrow W ′ as cooling air for cooling the catalyst 35. As described above, a large flow path for taking in the upper part of the tunnel under cover 40 is secured, and the flow rate of the cooling air W ′ can be secured more reliably.

  And since the said driving | running | working wind W can be drawn above the said tunnel undercover 40, without making it peel along the shape of the wind guide part 41k of the said air intake part 41, the flow volume of the said cooling wind W 'is made more. Can be surely secured.

  Further, as shown in FIG. 6 (b), the air guide portion 41k is formed to widen from the front to the rear of the vehicle body, so that the air W ′ flowing through the center of the air guide portion 41k. The air W ″ flowing through the side surface portions 41j and 41j of the air guide portion 41k becomes slow, and negative pressure is generated at the side surface portions 41j and 41j. As a result, the traveling wind W is drawn more into the air guide portion 41k, and the cooling efficiency of the catalyst 35 is further improved.

  As described above, according to the present invention, there is a possibility that the present invention can be suitably used in the field of manufacturing a vehicle body having an under cover that covers a lower portion of the vehicle.

DESCRIPTION OF SYMBOLS 1 Car body 11 Dash panel 11a Lower end part 35 of a dash panel Catalyst (Equipment which needs cooling)
40 Tunnel under cover (under cover)
41 Air intake portion 41a Basic surface portion 41f Stepped portion 41h Front end portion 41i of the air guide portion Rear end portion 41k of the air guide portion Air guide portion 41l Open portion 41m Rear end E of the opening portion E Engine room R Car compartment

Claims (3)

Equipment that needs cooling is deployed at the rear of the engine room, and
In the lower vehicle body structure of the vehicle provided with an under cover that covers the device and the lower part of the opening at the rear of the engine room,
The under cover is provided with an air intake portion on the front side of the device,
The air intake portion includes a step portion whose rear side is lower than the front side, a wind guide portion inclined upward from the front toward the rear behind the step portion, and an under cover from the rear end of the wind guide portion to the rear. An opening that opens upward,
The wind guide portion is formed to widen from the front to the rear of the vehicle body on both the left and right sides,
The lower body structure of a vehicle according to claim 1, wherein the rear end portion of the opening portion is formed on the rear side of the vehicle body with respect to the rear end portion of the air guide portion. The wind guide portion of the under cover is formed by raising a planar basic surface portion upward,
2. The vehicle according to claim 1, wherein the wind guide portion is formed of a downwardly convex curved portion continuous from the basic surface portion in a side view, and a curvature radius of the curved portion is 100 mm or more. Lower body structure.   The opening part of the air intake part in the said under cover is provided in the vehicle body front rather than the lower end part of the dash panel which partitions off the engine room and vehicle interior of a vehicle body. Lower body structure of the vehicle.

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