Labyrinth structure of intake duct for vehicle internal combustion engine

Abstract

A labyrinth structure 1 of an intake duct 2 includes an upper support member 6 extending rearward of the intake duct 2 and an upper mount bracket 5 extending downward of the intake duct 2. The labyrinth structure 1 also includes a pair of air guide plates 11 disposed outside the intake duct 2 and a cover member 10 covering the intake duct 2 and the upper support member 6. An intake port 2B of the intake duct 2 is opened toward a first air guide plate 11R, and an air gap is formed between the intake port 2B and the first air guide plate 11R. From the first air guide plate 11R, a projecting wall 11A projects toward an end portion 2A of the intake duct 2 where the intake port 2B is formed. A projecting end of the projecting wall 11A overlaps with the end portion 2A as viewed from the front, and an upper portion of the projecting wall 11A overlaps with a lower surface of the cover member 10 as viewed from the front.

Description

Labyrinth structure of intake duct for vehicle internal combustion engine

[0001] The present invention relates to a labyrinth structure of an intake duct for a vehicle internal combustion engine.

[0002] Patent Document 1 discloses an intake duct for an internal combustion engine, which is located above a radiator for the internal combustion engine mounted in the front of a vehicle. The intake duct extends in the vehicle width direction, and an intake port is opened at one end of the duct, facing the vehicle width direction. A water shield is also provided adjacent to the intake port, facing the intake port. The water shield prevents raindrops and the like from being sucked into the intake port.

[0003] Jikko No. 60-020498

[0004] However, in the structure disclosed in Patent Document 1, the air gap formed between the air intake and the water shield is open to the surroundings, which can allow foreign matter such as raindrops and dust to be sucked into the air intake duct from the air intake.

[0005] An object of the present invention is to provide a labyrinth structure of an intake duct for an internal combustion engine that can effectively prevent foreign matter such as raindrops from being sucked into the intake duct.

[0006] A labyrinth structure of an intake duct for a vehicle internal combustion engine according to one aspect of the present invention includes an intake duct extending in the vehicle width direction above a radiator core, an upper support member extending in the vehicle width direction behind the intake duct, and an upper mount bracket extending in the vehicle width direction below the intake duct. The labyrinth structure also includes a pair of first and second air guide plates disposed on the outer sides of the intake duct in the vehicle width direction to guide airflow generated by vehicle travel to the radiator core, and a cover member disposed above the intake duct and the upper support member to cover them. The intake port of the intake duct opens toward the first air guide plate, and an air gap is formed between the intake port and the first air guide plate. A protruding wall protrudes in the vehicle width direction from the first air guide plate toward the end of the intake duct where the intake port is formed. The protruding end of the protruding wall overlaps with the end of the intake duct as seen from the front, and the upper part of the protruding wall overlaps with the lower surface of the cover member as seen from the front.

[0007] The labyrinth structure of the intake duct described above can effectively prevent foreign matter such as raindrops from being sucked into the intake duct for an internal combustion engine.

[0008] FIG. 1 is an exploded perspective view of a labyrinth structure of an intake duct according to an embodiment. FIG. 2 is a partially exploded perspective view of the labyrinth structure. FIG. 3 is a partially exploded perspective view of the labyrinth structure. FIG. 4 is a perspective view of the labyrinth structure. FIG. 5 is a plan view of the labyrinth structure. FIG. 6 is a front view of the labyrinth structure (lower part omitted). FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6. FIG. 9 is a perspective rear view showing an upper support member and a cover member of the labyrinth structure. FIG. 10 is a perspective view showing a first air passageway of the labyrinth structure.

[0009] Hereinafter, a labyrinth structure 1 of an intake duct 2 for a vehicle internal combustion engine according to an embodiment will be described with reference to the drawings. In the following description, up, down, left, right, front, and rear refer to the vehicle. In each drawing, FR and RR indicate the front and rear in the longitudinal direction of the vehicle, respectively, LH and RH indicate the left and right in the width direction of the vehicle, and UP and DN indicate the upper and lower in the vertical direction, respectively. In the following description, the left and right in the width direction of the vehicle and the front, front side, rear, and rear sides in the longitudinal direction of the vehicle will be simply referred to as the left, right, front, front side, rear, and rear side, respectively. Furthermore, components having the same functions as those already described will be designated by the same reference numerals, and description thereof will be omitted.

[0010] The vehicle equipped with the labyrinth structure 1 of the embodiment is a hybrid electric vehicle (HEV) that includes an internal combustion engine (hereinafter referred to as an ICE) and an electric motor. The hybrid type may be a series type, a parallel type, a mixed type, or any other type, and is not limited thereto. Since the ICE is installed, the vehicle has an intake duct 2 and a radiator 3 for the ICE. These components are installed in the front of the vehicle. More specifically, these components are arranged behind a front bumper (not shown) and a front grille (not shown).

[0011] As shown in FIGS. 1 to 4 , a resin-made intake duct 2 extends in the vehicle width direction above a radiator core 3A (see FIGS. 6 to 8 ), which serves as a heat exchanger for a radiator 3. An intake port 2B (see FIGS. 1 and 5 ) is opened at an end 2A of the intake duct 2. The intake port 2B opens in the vehicle width direction, and in this embodiment, opens toward the right side of the vehicle. The end of the intake duct 2 opposite the intake port 2B is curved 90 degrees toward the rear, and a bellows-shaped resin or rubber joint duct 4 is attached to this opposite end, serving as a connection to an air filter box (not shown). The internal flow path of the intake duct 2 is formed from the end 2A, where the intake port 2B opens, to the end where the joint duct 4 is attached, with multiple resonators 2C formed along the way.

[0012] An upper support member 6 extends in the vehicle width direction behind the intake duct 2 and supports the upper part of the radiator 3 via a resin or metal upper mount bracket 5. The upper mount bracket 5 is located below the intake duct 2 and extends in the vehicle width direction. Four mounting pieces 5A extend upward from the rear edge of the upper mount bracket 5. The upper mount bracket 5 is attached to the upper support member 6 by fixing the mounting pieces 5A to the front surface of the upper support member 6 (see Figure 2).

[0013] An air conditioning (HVAC) condenser 7 is located in front of the radiator 3, and an electric motor radiator 8 is located in front of the condenser 7. The electric motor radiator 8 uses airflow during travel to cool the coolant for the electric motor and associated units such as the inverter. The condenser 7 and electric motor radiator 8 are supported by side tanks 3B, which are provided on both sides of the radiator core 3A, via brackets (not shown). The radiator 3 is mounted to the upper mount bracket 5 via bushings at the top of the side tanks 3B. In other words, the upper portion of the radiator core 3A between the pair of side tanks 3B is supported by the upper mount bracket 5. The radiator core 3A of the ICE radiator 3 and the cores of the condenser 7 and electric motor radiator 8 are referred to as a heat exchanger core group.

[0014] A seal member 5B is attached to the underside of the upper mount bracket 5. The seal member 5B is made of an elastically deformable foam material and is slightly compressed between the upper mount bracket 5 and the upper edge of the heat exchanger core group. The seal member 5B prevents airflow from flowing from front to rear between the upper mount bracket 5 and the heat exchanger core group. The radiator 3 is mounted to a lower support member (not shown) via a bushing at the lower end of the side tank 3B. A lower air guide 9 is fixed to the front surface of the lower support member directly below the condenser 7 and the electric motor radiator 8. The lower air guide 9 guides airflow so that it does not flow below the heat exchanger core group.

[0015] The upper support member 6 and the lower support member are pressed steel plates and are part of the vehicle body. The upper support member 6 is located rearward of the intake duct 2. However, the end of the intake duct 2 to which the joint duct 4 is attached extends over the upper support member 6. The intake duct 2 also has two mounting pieces 2D protruding rearward, which are fixed to the upper surface of the upper support member 6 (see Figure 5). The intake duct 2 also has a mounting protrusion 2E protruding downward (see Figure 8). The mounting protrusion 2E engages with an engaging hole 5C (see Figures 1 and 8) in the upper mount bracket 5. A lock bracket 6A is attached to the center of the upper support member 6 in the vehicle width direction. The lock latch that holds the lock striker located at the center of the front end of the hood (not shown) is attached to the lock bracket 6A.

[0016] A resin cover member 10 is provided above the intake duct 2 and the upper support member 6 so as to cover the intake duct 2 and the upper support member 6. The curved leading edge 10A of the cover member 10 is fixed to the upper edge of the front grille using a resin clip or the like. When the hood is closed, the leading edge 10A comes into contact with a seal member attached to the underside of the hood. The cover member 10 has a recess behind the leading edge 10A (see Figures 7 and 8), and a lock hole 10B is formed in the center of this recess in the vehicle width direction. When the hood is closed, the hood's lock striker passes through this lock hole 10B and is held by a lock latch attached to the lock bracket 6A.

[0017] When the hood is closed, the linear rear edge 10C of the recess in the cover member 10 comes into contact with a seal member attached to the underside of the hood. A box section 10D is formed in the center of the leading edge 10A in the vehicle width direction, and the internal space of the box section 10D communicates with the lock hole 10B. A lock lever (not shown) extending forward from the lock latch is disposed inside the box section 10D. Multiple mounting holes 10E (see FIG. 9) are formed along the rear edge of the cover member 10 itself. The rear edge of the cover member 10 is fixed to the upper surface of the upper support member 6 with a resin clip or the like.

[0018] As described above, the end of the intake duct 2 to which the joint duct 4 is attached passes over the upper support member 6. However, as shown in FIG. 9 , a notch 10F is formed in the left rear portion of the cover member 10 to allow this end of the intake duct 2 to exit. This notch 10F also functions as a second air passage formed between the cover member 10 and the upper support member 6. The second air passage path (notch 10F) allows air to flow rearward from the upper support member 6. Therefore, as shown in FIG. 5 , on the left side of the vehicle, the amount of air flowing below the cover member 10 can be increased, ensuring airflow from the left side to the right side toward the labyrinth structure 1. Meanwhile, foreign matter contained in the air flow on the left side can be discharged rearward from the upper support member 6 through the second air passage path (notch 10F).

[0019] In the vehicle widthwise section between the aforementioned midpoint of the intake duct 2 where the tip of the first seal member 13 is located and the second air guide plate 11L, the upper edge of the intake duct 2 (including the resonator 2C) (see dash-dotted line Y in FIG. 8 ) and the upper surface of the upper support member 6 (see dash-dotted line Z in FIG. 8 ) are positioned lower than the lower surface 10H of the cover member 10 (see dash-dotted line X in FIG. 8 ). This allows air traveling from the front to flow rearward through the gap between the intake duct 2 and the cover member 10, and then more easily through the gap between the upper support member 6 and the cover member 10. Meanwhile, as shown in FIGS. 7 and 9 , a downwardly extending restricting wall 10G is formed at the right rear of the cover member 10 (within the vehicle widthwise section where the first seal member 13 is provided). The restricting wall 10G restricts airflow rearward from the upper support member 6.

[0020] A pair of air guide plates 11 are disposed on the outer sides of the intake duct 2 in the vehicle width direction. The air guide plates 11 include a first air guide plate 11R disposed on the right side and a second air guide plate 11L disposed on the left side. The air guide plates 11 guide the airflow that has passed through the front grille and other components to the radiator core 3A. The air guide plates 11 also guide the airflow to the condenser 7 and the core of the electric motor radiator 8. The side tanks 3B of the radiator 3 are located further outward than the air guide plates 11. The intake port 2B of the intake duct 2 opens facing the first air guide plate 11R. An air gap 12 (see FIG. 5) is formed between the intake port 2B and the first air guide plate 11R.

[0021] A protruding wall 11A protrudes in the vehicle width direction from the first air guide plate 11R toward the end 2A of the intake duct 2. The protruding wall 11A has an L-shaped cross section and is composed of a vertical wall and a horizontal wall. The vertical wall of the protruding wall 11A is located in front of the end 2A of the intake duct 2. The horizontal wall of the protruding wall 11A is located below the end 2A of the intake duct 2. As shown in Figures 5 and 6, the protruding end, i.e., the free end, of the protruding wall 11A overlaps the end 2A of the intake duct 2 in the vehicle width direction and up-down direction when viewed from the front. Furthermore, as shown in Figure 7, the upper portion 11A1 of the protruding wall 11A overlaps the lower surface 10H of the cover member 10 in the vehicle width direction and up-down direction when viewed from the front. The protruding wall 11A will be described in more detail below.

[0022] A first seal member 13 is provided between the upper surface of the intake duct 2 and the lower surface 10H of the cover member 10, extending in the vehicle width direction from the end 2A of the intake duct 2 to partway along the intake duct 2. In this embodiment, the first seal member 13 extends to the vicinity of the lock bracket 6A of the upper support member 6. The first seal member 13 is attached to the upper surface of the intake duct 2. The first seal member 13 is made of an elastically deformable foam material, and is slightly compressed between the intake duct 2 and the cover member 10. The first seal member 13 prevents traveling wind from flowing from front to rear between the intake duct 2 and the cover member 10.

[0023] A second seal member 14 is provided between the lower surface of the intake duct 2 and the upper surface of the upper mount bracket 5, extending in the vehicle width direction from the end 2A of the intake duct 2. In this embodiment, the second seal member 14 extends to the curved portion of the intake duct 2 on the opposite side from the end 2A. The second seal member 14 is attached to the lower surface of the intake duct 2. The second seal member 14 is also made of an elastically deformable foam material, and is slightly compressed between the intake duct 2 and the upper mount bracket 5. The second seal member 14 prevents traveling wind from flowing from front to rear between the intake duct 2 and the upper mount bracket 5.

[0024] A third seal member 15 is provided between the end 2A of the intake duct 2 and the protruding wall 11A, and between the end 2A of the intake duct 2 and the cover member 10. As shown in FIG. 7 , the third seal member 15 is attached to the outer surface of the intake duct 2 along the front portion of the intake port 2B. The third seal member 15 is made of an elastically deformable foam material and is slightly compressed between the end 2A and the protruding wall 11A and between the end 2A and the cover member 10. The third seal member 15 prevents traveling wind from flowing into the air gap 12 through the gap between the end 2A and the protruding wall 11A and the gap between the end 2A and the cover member 10.

[0025] A fourth seal member 16 is provided between the lower surface (horizontal wall) of the protruding wall 11A and the upper surface of the upper mount bracket 5. The fourth seal member 16 is attached to the lower surface of the protruding wall 11A. The fourth seal member 16 is made of an elastically deformable foam material and is slightly compressed between the lower surface of the protruding wall 11A and the upper surface of the upper mount bracket 5. The fourth seal member 16 prevents traveling wind from flowing into the air gap 12 through the gap between the protruding wall 11A and the upper mount bracket 5. The end face of the first seal member 13 contacts the upper end side surface of the third seal member 15. The end face of the second seal member 14 contacts the lower end side surface of the third seal member 15. The front end surface of the second seal member 14 contacts the rear surface of the fourth seal member 16.

[0026] The aforementioned restricting wall 10G (see FIG. 9 ) of the cover member 10 is located rearward of the first seal member 13. The restricting wall 10G is part of the cover member 10, but can also be considered to be formed between the cover member 10 and the upper support member 6. The second air passage formed as the aforementioned notch 10F of the cover member 10 can also be considered to be formed between the cover member 10 and the upper support member 6. The first seal member 13 extends from the end 2A of the intake duct 2 to a midpoint in the intake duct 2, and the second air passage path (notch 10F) is formed within the section in the vehicle width direction between this midpoint and the second air guide plate 11L. Furthermore, as shown in FIGS. 9 and 10 , a first air passage path 17 is formed between the cover member 10 and the upper support member 6 behind the first air guide plate 11R. Similar to the second air passage path (notch 10F), the first air passage path 17 allows air to flow rearward from the upper support member 6. The above-mentioned restraining wall 10G that restrains the air flow rearward from the upper support member 6 is formed adjacent to the first air passage 17 .

[0027] The labyrinth structure 1 shown in Fig. 5 is formed with the above-described configuration. By arranging the above-described multiple sealing members in the labyrinth structure 1, the traveling wind changes its flow direction multiple times before being drawn into the inside of the intake duct 2 through the air intake port 2B, as indicated by the multiple arrows in Fig. 5. In particular, in the above-described air gap 12, the flow direction of the traveling wind is turned 180 degrees by the first air guide plate 11R and drawn into the inside of the intake duct 2 through the air intake port 2B. Note that some of the traveling wind flows rearward of the first air guide plate 11R and passes through the first air passage 17 to the rear of the upper support member 6, while some of the traveling wind flows straight without being turned and passes through the second air passage (notch 10F) to the rear of the upper support member 6.

[0028] The airflow caused by driving includes raindrops, snowflakes, sand, mud, dust, and the like. These foreign objects have a greater mass than the air that constitutes the driving airflow. By rotating the airflow multiple times using the labyrinth structure 1, these foreign objects are blown away by inertia and are discharged rearward from the upper support member 6 through the first air passage 17 and the second air passage (notch 10F). Alternatively, these foreign objects may collide with the inner surface of the flow path within the labyrinth structure 1 and not be blown downstream. As a result, it is possible to prevent foreign objects from mixing into the intake air that is drawn into the intake duct 2 through the intake port 2B.

[0029] Here, above the intake duct 2, the traveling wind is diverted so as to bypass the first seal member 13. In this embodiment, below the intake duct 2, the second seal member 14 almost completely prevents the traveling wind from flowing rearward. However, a bypass flow similar to that above the intake duct 2 may also be generated below the intake duct 2. Therefore, the length of the second seal member 14 only needs to be at least equal to the length of the first seal member 13.

[0030] The airflow within the labyrinth structure 1 is predominantly a flow that is redirected several times, as indicated by the arrows in FIG. 5 . However, as shown in FIG. 7 , air also flows into the air gap 12 through the gap between the protruding wall 11A and the underside 10H of the cover member 10. The protruding wall 11A is shaped and positioned to remove raindrops and other foreign objects from this airflow. As described above, the protruding wall 11A is positioned so that its upper portion 11A1 overlaps the underside 10H of the cover member 10 when viewed from the front. This prevents the airflow from flowing linearly into the air gap 12 along with foreign objects from the front. The first, second, and third seal members 13, 14, and 15 (particularly the third seal member 15) suppress airflow around the protruding end, i.e., the free end, of the protruding wall 11A.

[0031] Wind from the front impacts the vertical wall of the protruding wall 11A, causing foreign objects such as raindrops to adhere to the vertical wall. The wind passes through the heat exchanger core group, but flow resistance can create an air current that rises along the vertical wall. To prevent these foreign objects from climbing over the vertical wall due to this rising air current, the upper portion 11A1 of the protruding wall 11A forms a forward-sloping inclined portion 11A1 at an angle of 45° or more relative to the horizontal. That is, the angle α in FIG. 7 is 45° or more. Furthermore, a flange 11A2 is formed on the upper edge of the inclined portion 11A1, inclined further forward than the inclined portion 11A1. Even if raindrops or other foreign objects flow upward along the front surface of the inclined portion 11A1 due to the rising air current, the formation of this flange 11A2 prevents the raindrops or other foreign objects from climbing over the protruding wall 11A.

[0032] The effects of the labyrinth structure 1 of the intake duct 2 according to the above embodiment will be described.

[0033] (1) The labyrinth structure 1 of this embodiment includes an upper support member 6 extending rearward of the intake duct 2 and an upper mount bracket 5 extending downward from the intake duct. The labyrinth structure 1 also includes a pair of air guide plates 11 disposed on the outer sides of the intake duct 2 in the vehicle width direction, and a cover member 10 covering the intake duct 2 and the upper support member 6. The intake port 2B of the intake duct 2 opens toward the first air guide plate 11R, and an air gap 12 is formed between the intake port 2B and the first air guide plate 11R. A protruding wall 11A protrudes from the first air guide plate 11R toward the end 2A where the intake port 2B of the intake duct 2 is formed. The protruding end of the protruding wall 11A overlaps the end 2A described above when viewed from the front, and the upper portion of the protruding wall 11A overlaps the lower surface 10H of the cover member 10 when viewed from the front.

[0034] Furthermore, a first seal member 13 is provided between the upper surface of the intake duct 2 and the lower surface 10H of the cover member 10. The first seal member 13 extends from the end 2A to partway along the intake duct 2 in the vehicle width direction. A second seal member 14 is provided between the lower surface of the intake duct 2 and the upper surface of the upper mount bracket 5. The second seal member 14 extends from the end 2A in the vehicle width direction and has a length equal to or greater than the length of the first seal member 13. Therefore, as shown in FIG. 5 , the traveling wind is redirected around the first seal member 13 and then turned 180 degrees in the air gap 12 before being drawn into the intake duct 2. In this way, the intake duct 2 itself and the seal members 13 and 14 form a labyrinth structure 1 that redirects the air flow several times, allowing intake air that does not contain foreign matter such as raindrops to be drawn into the intake duct 2.

[0035] 7, the upper portion 11A1 of the protruding wall 11A overlaps with the underside of the cover member 10 when viewed from the front. Therefore, foreign matter contained in the wind from the front does not flow directly into the air gap 12, and the foreign matter is blocked by the upper portion 11A1, preventing it from being sucked into the intake duct 2. Note that when the ICE is operating at high load and high speed, the negative pressure near the intake port 2B of the intake duct 2 increases. In this embodiment, the air gap 12 is formed, which prevents this negative pressure from causing the first air guide plate 11R to stick to the intake port 2B, thereby preventing intake obstruction.

[0036] (2) In this embodiment, a third seal member 15 is also provided between the end 2A of the intake duct 2 and the protruding end of the protruding wall 11A. The third seal member 15 also seals between the end 2A and the cover member 10. Therefore, the third seal member 15 suppresses the airflow caused by traveling around the protruding end of the protruding wall 11A and into the air gap 12, preventing foreign matter from being sucked into the intake duct via this route. The third seal member 15 contacts not only the protruding wall 11A but also the underside 10H of the cover member 10, thereby suppressing the airflow caused by traveling from flowing around above the end 2A.

[0037] (3) Furthermore, in this embodiment, a suppression wall 10G that suppresses air flow rearward from the upper support member 6 is formed between the cover member 10 and the upper support member 6 at least rearward of the first seal member 13. Therefore, the air flow that flows rearward from the first seal member 13 is guided by the suppression wall 10G to the air gap 12. Furthermore, a first air passage path 17 that allows air to flow rearward from the upper support member 6 is formed rearward of the first air guide plate 11R between the cover member 10 and the upper support member 6. Therefore, foreign matter contained in the air flow guided by the suppression wall 10G to the air gap 12 turns 180 degrees in the air gap 12 and is discharged rearward from the upper support member 6 through the first air passage path 17 without being sucked into the intake port 2B. As a result, foreign matter is further prevented from being sucked into the intake duct 2.

[0038] (4) In the embodiment, the upper portion 11A1 of the protruding wall 11A forms a forwardly inclined inclined portion 11A1 having an inclination angle of 45° or more with respect to the horizontal. Therefore, at least the upper portion 11A1 of the protruding wall 11A is formed as a wall portion closer to vertical, which more reliably prevents foreign objects contained in the airflow from the front from colliding with the upper portion 11A1 and flowing into the air gap 12. Even if an ascending air current forms in front of the protruding wall 11A, the upper portion 11A1 is formed as a wall portion closer to vertical, which prevents foreign objects from climbing up the front surface of the upper portion 11A1 and climbing over the protruding wall 11A. Furthermore, by forming the upper portion 11A1 as a forward-inclined inclined portion 11A1, foreign objects are more reliably prevented from climbing up the front surface of the upper portion 11A1 and climbing over the protruding wall 11A.

[0039] (5) Furthermore, in this embodiment, the upper edge of the inclined portion 11A1 is formed with a flange 11A2 that is inclined further forward than the inclined portion 11A1. Therefore, even if a foreign object climbs up the front surface of the upper portion 11A1 and reaches the upper edge of the protruding wall 11A, the further forward-inclined flange 11A2 formed on this upper edge can more reliably prevent the foreign object from climbing over the protruding wall 11A.

[0040] (6) In the embodiment, in the section in the vehicle width direction between the second air guide plate 11L and the midpoint of the intake duct 2 where the tip of the first seal member 13 is located, the upper edge of the intake duct 2 (see dash-dotted line Y in FIG. 8) and the upper surface of the upper support member 6 (see dash-dotted line Z in FIG. 8) are positioned lower than the lower surface 10H of the cover member 10 (see dash-dotted line X in FIG. 8). Therefore, foreign matter contained in the airflow from the front can be discharged rearward without being resisted by the intake duct 2 or the upper support member 6.

[0041] The above-described embodiments are merely examples provided to facilitate understanding of the invention. The technical scope of the invention is not limited to the specific technical details disclosed in the above-described embodiments, but also includes various modifications, changes, and alternative technologies that can be easily derived therefrom. For example, the vehicle in the above-described embodiments is an HEV, but it may also be an ICE vehicle that does not have a drive electric motor. Furthermore, the second seal member 14 and the fourth seal member 16 in the above-described embodiments may be integrated, in which case the second seal member 14 also functions as the fourth seal member 16.

[0042] REFERENCE SIGNS LIST 1 Labyrinth structure 2 Intake duct 2A End 2B Intake port 3 (ICE) Radiator 3A Radiator core 5 Upper mount bracket 6 Upper support member 10 Cover member 10H Underside 10F Notch (second air passage path) 11 Air guide plate 11R First air guide plate 11L Second air guide plate 11A Protruding wall 11A1 Inclined portion (upper part of protruding wall 11A) 11A2 Flange 12 Air gap 13 First seal member 14 Second seal member 15 Third seal member 17 First air passage path

Claims

1. A labyrinth structure of an intake duct for a vehicle internal combustion engine, comprising: an intake duct for the internal combustion engine, the intake duct extending in the vehicle width direction above a radiator core for the internal combustion engine disposed at the front of the vehicle, and having an intake port at an end that opens toward the vehicle width direction; an upper support member extending in the vehicle width direction behind the intake duct and supporting an upper part of the radiator core via an upper mount bracket; an upper mount bracket extending in the vehicle width direction below the intake duct and attaching the upper part of the radiator core to the upper support member; a pair of first and second air guide plates disposed respectively outside the intake duct in the vehicle width direction and for guiding airflow caused by running to the radiator core; and a cover member disposed above the intake duct and the upper support member so as to cover the intake duct and the upper support member, the intake port is open toward the first air guide plate, and an air gap is formed between the intake port and the first air guide plate; a protruding wall is provided in the vehicle width direction from the first air guide plate toward the end of the intake duct; a first seal member is provided between the upper surface of the intake duct and the lower surface of the cover member, extending in the vehicle width direction from the end to halfway along the intake duct; a second seal member having a length equal to or greater than the length of the first seal member is provided between the lower surface of the intake duct and the upper surface of the upper mount bracket, extending from the end in the vehicle width direction; and a labyrinth structure of the intake duct, in which the protruding end of the protruding wall overlaps with the end of the intake duct when viewed from the front, and an upper portion of the protruding wall overlaps with the lower surface of the cover member when viewed from the front.

2. A labyrinth structure for an intake duct as set forth in claim 1, wherein a third seal member is provided between the end of the intake duct and the protruding end of the protruding wall, and the third seal member also seals between the end and the cover member.

3. A labyrinth structure of an intake duct as claimed in claim 1 or 2, wherein a restricting wall is formed between the cover member and the upper support member at least to the rear of the first seal member to restrict air flow to the rear of the upper support member, and a first air passage is formed between the cover member and the upper support member to the rear of the first air guide plate to allow air to flow to the rear of the upper support member.

4. A labyrinth structure for an intake duct according to any one of claims 1 to 3, wherein the upper part of the protruding wall forms a sloped portion that slopes forward at an angle of 45° or more with respect to the horizontal.

5. A labyrinth structure for an intake duct as set forth in claim 4, wherein a flange is formed on the upper edge of the inclined portion, inclined further forward than the inclined portion.

6. A labyrinth structure of an intake duct as claimed in any one of claims 1 to 5, wherein, within the section in the vehicle width direction between the middle of the intake duct and the second air guide plate, the upper edge of the intake duct and the upper surface of the upper support member are positioned lower than the lower surface of the cover member.

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