JP2012040912A - Engine cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine cover capable of improving the muffling effect, and efficiently executing the heat radiation.SOLUTION: In the engine cover 10, a sound absorbing material 20 formed of resin foam is fixed inside a cover body 11 of a tray structure. The cover body 11 has an air inlet port 15 and an air outlet port 17 for introducing the outside air therein so as to flow between the sound absorbing material 20 and an engine 90. A pair of noise introducing ports 28, 29 are formed in the sound absorbing material 20 so as to be longitudinally arranged in the air flowing direction. A Helmholtz resonator chamber 27 is formed between the sound absorbing material 20 and the cover body 11 so as to perform the communication between the pair of noise introducing ports 28, 29.

Description

  The present invention relates to an engine cover that is provided with a sound absorbing material fixed inside a cover body having a tray structure, and that is fixed to a vehicle in a state where the sound absorbing material is disposed opposite to the engine of the vehicle.

  In general, when an engine cover is attached to a vehicle, the noise of the engine is reduced, but there is a problem that heat dissipation of the engine is hindered. On the other hand, there is known an apparatus in which an air inlet and an air outlet are provided in a cover main body to allow air between the engine cover and the engine to flow (see, for example, Patent Document 1).

JP 2007-170241 A (FIGS. 4 and 5, paragraphs [0018] and [0019])

  By the way, the conventional engine cover provided with the above-described air inlet and the like cannot obtain a sufficient silencing effect because the sound absorbing material has a simple flat plate structure. On the other hand, it is conceivable to improve the silencing effect by providing a Helmholtz resonance room in the sound absorbing material, but if a general Helmholtz resonance room with a bag path structure is provided, heat will accumulate in the Helmholtz resonance room and heat will be dissipated efficiently. Things that couldn't be done could have occurred.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an engine cover that can improve the silencing effect and can efficiently dissipate heat.

  The engine cover (10, 10V) according to the invention of claim 1 made to solve the above problems includes a sound absorbing material (20) made of foamed resin fixed inside a cover body (11) having a tray structure. In the engine cover (10, 10V) fixed to the vehicle with the sound absorbing material (20) facing the engine (90) of the vehicle, the cover body (11) is formed on the cover body (11). ) Formed in the cover main body (11) and the air introduction port (15) for introducing into the sound absorbing material (20) and flowing between the engine (90) and the air in the cover main body (11). An air discharge port (17) for discharging to the outside and an air flow formed from the air introduction port (15) to the air discharge port (17) formed in the sound absorbing material (20) and opening toward the engine (90). Arranged to move back and forth in the direction The inside of the sound absorbing material (20) or the sound absorbing material (20) and the cover main body (20) so as to communicate between the pair of noise introducing ports (28, 29) and the pair of noise introducing ports (28, 29). 11) and a Helmholtz resonance chamber (27) capable of reducing the noise introduced from the pair of noise introduction ports (28, 29) by Helmholtz resonance.

  In the present invention, “opposite the engine” includes both cases of “opposite the engine apart” and “opposite the engine closely”.

  A second aspect of the present invention is the engine cover (10, 10V) according to the first aspect, wherein the noise absorbing material (20) has a plurality of noise reduction protrusions on the surface (23) facing the engine (90). (24, 24V) is formed, and the air introduced into the cover body (11) from the air inlet (15) flows through the gap (30) between the noise reduction projections (24, 24V). It has the characteristic in the place comprised in this way.

  According to a third aspect of the present invention, in the engine cover (10, 10V) according to the second aspect, the air inlet (15) and the air outlet (17) are arranged so as to move back and forth in the vehicle traveling direction (X). The plurality of noise reduction protrusions (24) are characterized in that they are a plurality of triangular protrusions (24) having a triangular cross-section extending in the vehicle traveling direction (X) and arranged side by side.

  According to a fourth aspect of the present invention, in the engine cover (10, 10V) according to the third aspect, the pair of noise introduction ports (28, 29) is configured to include all or part of the plurality of triangular protrusions (24). A plurality of triangular protrusions are formed between a pair of noise introduction ports (28, 29) on the surface of the sound absorbing material (20) facing the engine (90), and are formed so as to cross at two positions in the middle in the longitudinal direction. (24) is characterized in that a block portion (26) that is closer to or in close contact with the engine (90) is provided.

  According to a fifth aspect of the present invention, in the engine cover (10, 10V) according to any one of the first to fourth aspects, the air introduction port (15) is a bottom of the tray structure of the cover body (11). The cover (11) is disposed on the wall (14) and projects into the cover body (11) obliquely forward and outward from the rear opening edge of the vehicle traveling direction (X) in the air introduction port (15). It is characterized in that a guide piece (16) for guiding air to (15) is formed.

  According to a sixth aspect of the present invention, in the engine cover (10, 10V) according to the fifth aspect, the sound absorbing material (20) rises from the rear opening edge of the air introduction port (15) and moves backward. It is characterized in that an internal guide slope (21) that is inclined so as to gradually approach the engine (90) is formed.

  A seventh aspect of the invention is directed to the engine cover (10, 10V) according to any one of the first to sixth aspects, wherein a movable lid (40) capable of changing an opening degree of the air inlet (15) is provided. In response to the heat of the engine (90), the air is deformed and the opening of the air inlet (15) is increased as the temperature of the engine (90) increases, while the air inlet ( It is characterized in that it includes an opening changing section (41) for driving the movable lid (40) so as to reduce the opening of 15).

[Invention of Claim 1]
In the engine cover (10, 10V) according to claim 1, the noise from the engine (90) can be reduced by the silencing effect of the sound absorbing material (20) itself, and the Helmholtz resonance from the noise inlet (28, 29). It can be taken into the room (27) and lowered. Thereby, the silencing effect is improved as compared with the conventional one in which the sound absorbing material (20) is simply provided. Further, air is introduced into the cover body (11) from the air inlet (15) of the cover body (11) to flow between the sound absorbing material (20) and the engine (90), and the air outlet (17). The heat between the sound absorbing material (20) and the engine (90) is smoothly eliminated. Moreover, since the noise inlets (28, 29) to the Helmholtz resonance room (27) are provided in pairs so as to move back and forth in the air flow direction, the air in the Helmholtz resonance room (27) is changed from one to the other. To the noise inlets (28, 29), and heat retention is prevented. That is, according to the engine cover (10, 10V) of the present invention, the silencing effect is improved as compared with the conventional one, and the heat radiation can be efficiently performed.

[Invention of claim 2]
In the engine cover (10, 10V) according to the second aspect, since the plurality of noise reduction projections (24, 24V) are provided in addition to the Helmholtz resonance chamber (27), the noise reduction effect is further improved. Moreover, since the air introduced into the cover main body (11) from the air inlet (15) flows through the gap (30) between the noise reduction projections (24, 24V), the accumulation of heat is also prevented. It is.

[Invention of claim 3]
In the engine cover (10, 10V) according to the third aspect, when the vehicle travels, the air introduced into the cover body (11) from the air introduction port (15) moves rearward in the vehicle traveling direction (X) and is exhausted. It is discharged from the outlet (17). Moreover, since the some triangular protrusion (24) as a noise reduction protrusion (24) is extended in the vehicle advancing direction (X) on the surface facing an engine (90) among sound-absorbing materials (20), Air can smoothly flow through the gap (30) between the triangular protrusions (24), and heat can be efficiently removed.

[Invention of claim 4]
In the engine cover (10, 10V) according to claim 4, the air that has flowed through the gap (30) between the triangular protrusions (24) collides with the block portion (26), and one noise inlet (28, 29), the air in the Helmholtz resonance chamber (27) can surely flow and heat can be efficiently removed.

[Invention of claim 5]
In the engine cover (10, 10V) according to claim 5, since the air inlet (15) is arranged on the bottom wall (14) of the tray structure, the air taken into the cover body (11) is taken into the engine (90). It is possible to promote heat dissipation by colliding with the outer surface of the. Further, since the guide piece (16) projecting obliquely outward and forward is provided from the opening edge on the rear side of the air introduction port (15), air is efficiently introduced into the air introduction port (15) when the vehicle is traveling. can do.

[Invention of claim 6]
In the engine cover (10, 10V) according to claim 6, the air introduced into the cover main body (11) from the air introduction port (15) is smoothly guided by the inner guide slope (21) of the sound absorbing material (20). It can flow to the engine (90) side.

[Invention of Claim 7]
In the engine cover (10, 10V) according to the seventh aspect, since the opening degree of the air inlet (15) automatically increases when the temperature of the engine (90) is high, overheating of the engine (90) is prevented. On the other hand, when the temperature of the engine (90) is low, the opening degree of the air inlet (15) is automatically reduced, so that warm-up is promoted and fuel efficiency is improved.

The perspective view of the engine cover which concerns on 1st Embodiment of this invention. Side view of engine cover Sectional drawing of the engine cover in the AA cut surface of FIG. Sectional drawing of the engine cover in the BB cut surface of FIG. The sectional side view which expanded a part of engine cover of a 2nd embodiment. The perspective view of the protrusion for noise reduction which concerns on the modification of this invention

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the engine cover 10 of this embodiment includes a sound absorbing material 20 inside a cover body 11 having a tray structure, and is fixed to the lower surface of a vehicle engine 90 as shown in FIG. 2, for example. The The cover main body 11 is a molded product of a synthetic resin (for example, PP, nylon, PBT) and has a substantially square planar shape. Further, fixed flanges 12 are formed on a total of three sides of the outer edge portion of the cover body 11, that is, one side at the front end in the vehicle traveling direction X and two sides on both sides thereof. The fixing flange 12 is formed by orthogonally crossing strip-like plates extending along the three sides, and has a gate shape as a whole. A plurality of bolt insertion holes 12 </ b> A are formed through each side of the fixed flange 12. The engine cover 10 is fixed to the engine 90 with bolts inserted through these bolt insertion holes 12A.

  As shown in FIG. 2, the rear end portion of the cover body 11 surrounded by the fixed flange 12 is a bottom upper wall 13 that is recessed toward the side away from the engine 90 from the fixed flange 12. Further, a range of the cover main body 11 surrounded by the fixing flange 12 and the bottom upper wall 13 is a bottom wall 14 that is further depressed than the bottom upper wall 13. Further, the bottom upper wall 13 and the bottom wall 14 have a flat plate shape parallel to the fixing flange 12.

  The step surface between the fixed flange 12 and the bottom upper wall 13 is inclined so as to protrude toward the center of the bottom upper wall 13 as it goes downward. Further, the step surface between the bottom upper wall 13 and the bottom wall 14 and the step surface between the fixing flange 12 and the bottom wall 14 are inclined so as to protrude toward the center side of the bottom wall 14 toward the lower side. is doing.

  As shown in FIG. 1, an air inlet 15 is formed in the bottom wall 14 along the front edge thereof. Further, as shown in FIG. 2, the guide piece 16 protrudes obliquely forward and outward from the opening edge on the rear side of the vehicle traveling direction X in the air introduction port 15. The guide piece 16 has substantially the same size as the air introduction port 15, and the guide piece 16 and the air introduction port 15 are just cut off by cutting a part of the bottom wall 14 into a protruding piece shape and bending it outward. It has a formed structure. Moreover, the opening which was enclosed by the bottom upper wall 13 and the level | step difference surface of the both sides and was open | released back is the air discharge port 17 which concerns on this invention.

  The sound absorbing material 20 is, for example, a synthetic resin (for example, urethane) foam-molded product, and is fixed in a range from the rear opening edge of the air introduction port 15 to the position near the rear end of the bottom upper wall 13. . The front end portion of the sound absorbing material 20 is provided with an internal guide slope 21 inclined obliquely rearward and upward from the opening edge on the rear side of the air inlet 15 toward the engine 90. Further, the rear end portion of the sound absorbing material 20 is a rear end vertical surface 22 that is arranged slightly forward from the rear end portion of the cover body 11 and rises vertically from the bottom upper wall 13.

  As shown in FIG. 1, a plurality of triangular ridges 24 having a triangular cross section extending in the vehicle traveling direction X are arranged side by side on the engine facing surface 23 between the inner guide inclined surface 21 and the rear end vertical surface 22 of the sound absorbing material 20. Is provided. And the cross-sectional shape orthogonal to the vehicle advancing direction X in these triangular protrusions 24 group is a triangular wave shape where the upper and lower peak portions are rounded as shown in FIG. Further, the apex of the triangular protrusion 24 is at a height in contact with the surface including the contact surface with the engine 90 in the fixed flange 12. Further, side flat surfaces 25, 25 having the same height as the apex of the triangular protrusion 24 are formed on both side edges of the engine facing surface 23.

  As shown in FIG. 1, a block portion 26 is provided at a position near the front end in the vehicle traveling direction X on the engine facing surface 23 of the sound absorbing material 20 at a position close to one end side in the left-right direction. The block portion 26 has a rectangular shape whose left-right direction is larger than the vehicle traveling direction X, and traverses the plurality of triangular protrusions 24 in the left-right direction. Further, the upper surface 26A of the block portion 26 is flat, and is located at the same height as the apex of the triangular protrusion 24 and the side flat surfaces 25, 25 as shown in FIG.

  As shown in FIG. 4, a Helmholtz resonance chamber 27 according to the present invention is formed below the block portion 26 between the sound absorbing material 20 and the cover main body 11. Further, as shown in FIG. 2, a pair of noise introduction ports 28 and 29 for taking in noise from the engine 90 into the Helmholtz resonance chamber 27 are provided along the front end face 26F and the rear end face 26B of the block portion 26. It is formed in a slit shape that penetrates 20 up and down.

  Specifically, as shown in FIGS. 1 and 4, the Helmholtz resonance chamber 27 and the pair of noise introduction ports 28 and 29 are formed from a position near one end to a position near the other end of the block portion 26 in the left-right direction. ing. In addition, the Helmholtz resonance chamber 27 of the present embodiment has a substantially rectangular parallelepiped shape that is flat in the thickness direction of the engine cover 10. As shown in FIG. 2, the front inner surface 27A and the rear inner surface 27B of the Helmholtz resonance chamber 27 are slightly inclined. Specifically, the front inner surface 27A of the Helmholtz resonance chamber 27 is continuous from the front opening edge of the noise introduction port 28 in the engine facing surface 23, and slightly protrudes rearward toward the lower inner surface 27C of the Helmholtz resonance chamber 27. It is inclined to. On the other hand, the rear inner surface 27B of the Helmholtz resonance chamber 27 is continuous from the rear opening edge of the noise introduction port 29 in the engine facing surface 23, and slightly protrudes forward toward the lower inner surface 27C of the Helmholtz resonance chamber 27. Inclined. Further, the lower end portions of the front end surface 26F and the rear end surface 26B of the block portion 26 are positioned between the front inner surface 27A and the rear inner surface 27B in the vertical direction of the engine cover 10. The opening areas of the noise introduction ports 28 and 29 are minimized at the lower end portions of the front end surface 26F and the rear end surface 26B of the block portion 26, and the opening of the cut surface perpendicular to the vehicle traveling direction X of the Helmholtz resonance chamber 27 is provided. The area is, for example, approximately twice the minimum opening area of the noise inlets 28 and 29.

  This completes the description of the configuration of the engine cover 10 of the present embodiment. Next, the function and effect of the engine cover 10 will be described. As shown in FIG. 2, the engine cover 10 is fixed to the lower surface of the engine 90 with bolts in a state where the sound absorbing material 20 faces the engine 90. When the engine cover 10 is fixed to the engine 90, as shown in FIG. 4, the upper surface 26A of the block portion 26 of the sound absorbing material 20, the side flat surfaces 25, and the apexes of the triangular protrusions 24 are in contact with the engine 90. Become. A plurality of V-shaped gaps 30 sandwiched between the triangular protrusions 24, 24 are formed between the sound absorbing material 20 and the engine 90, and a pair of noises as shown in FIG. The inlets 28 and 29 are in a state of facing the lower surface of the engine 90.

  Now, when the engine 90 is started, the noise of the engine 90 is absorbed and reduced by the plurality of V-shaped groove 30 between the sound absorbing material 20 and the engine 90, and the noise of the engine 90 is a pair of noises. Reduced by being taken into the Helmholtz resonance chamber 27 from the inlets 28 and 29. As a result, it is possible to obtain a higher silencing effect than that in which the sound absorbing material 20 itself simply absorbs noise.

  By the way, when the temperature of the engine 90 rises, the temperature of the air between the engine cover 10 and the engine 90 also rises. However, when the vehicle travels, as shown by the arrow in FIG. 2, the outside air is guided by the guide piece 16 and flows into the air introduction port 15, and is guided by the internal guide slope 21 to the lower surface of the engine 90. Collide and flow into a plurality of V-shaped gaps 30. The air that has flowed into some of the V-shaped gaps 30 flows straight from the front end to the rear end of the sound absorbing material 20 and is discharged from the air discharge port 17 to the outside of the engine cover 10. Further, the air that has flown into the other part of the V-shaped groove 30 collides with the front end surface 26F of the block portion 26, and flows into the Helmholtz resonance chamber 27 from the noise introduction port 28 on the front side. To the noise introduction port 29, the rear V-shaped gap 30, and the air discharge port 17, and is discharged out of the engine cover 10. In this way, not only the air in the gap 30 between the sound absorbing material 20 and the engine 90 but also the air in the Helmholtz resonance chamber 27 flows to prevent heat retention.

  That is, according to the engine cover 10 of the present embodiment, the silencing effect is improved as compared with the conventional one, and the heat radiation can be efficiently performed. Moreover, since the air introduced from the air introduction port 15 collides with the outer surface of the engine 90, heat dissipation is promoted. Furthermore, since the air introduced into the cover body 11 from the air introduction port 15 is guided obliquely rearward by the internal guide slope 21, the air smoothly flows into the gap 30 between the engine 90 and the sound absorbing material 20. . In addition, since the guide piece 16 protrudes obliquely forward and outward from the rear opening edge of the air inlet 15, the outside air can be efficiently introduced into the air inlet 15.

[Second Embodiment]
FIG. 5 shows an enlarged view of the peripheral portion of the air inlet 15 in the engine cover 10V of the present embodiment. As shown in the figure, in the engine cover 10V of this embodiment, the movable lid 40 is rotatably connected to the rear opening edge of the air introduction port 15 via a hinge 40H instead of the guide piece 16 described above. Yes. The bimetal 41 is attached across the upper surface of the bottom wall 14 of the cover main body 11 and the movable lid 40 with the movable lid 40 in a half-open state. The bimetal 41 is heated by the heat of the engine 90 and expands, and the movable lid 40 is rotated so as to increase the opening of the air inlet 15 as the temperature rises. Since other configurations are the same as those in the first embodiment, a duplicate description is omitted. According to the present embodiment, when the temperature of the engine 90 is high, the opening degree of the air inlet 15 is automatically increased, so that overheating of the engine 90 is prevented. On the other hand, when the temperature of the engine 90 is low, the opening degree of the air inlet 15 is automatically reduced, so that warm-up is promoted and fuel consumption is improved.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) Although the engine cover 10 of the first embodiment is attached to the lower surface of the engine 90, the present invention may be applied to an engine cover attached to an upper surface or a side surface of the engine.

  (2) Although the engine cover 10 of the first embodiment is fixed by the engine 90, the engine cover may be fixed to a surface facing the engine in the engine room of the vehicle and may be disposed facing the engine.

  (3) In the engine cover 10V of the second embodiment, the bimetal 41 is provided as the “opening changing portion” of the present invention, but it may be a shape memory alloy or a thermostat.

  (4) In the first embodiment, the sound absorbing material 20 is provided with the plurality of triangular protrusions 24 as the “noise reduction protrusions” of the present invention. For example, the plurality of conical protrusions shown in FIG. The portion 24V may be provided as the “noise reduction projection” of the present invention. Further, the engine cover of the engine cover may have a flat surface facing the engine and may not have the “noise reduction protrusion” of the present invention.

  (5) In the first embodiment, the air inlet 15 and the air outlet 17 are arranged so as to move back and forth in the vehicle traveling direction X, but the air inlet and the air exhaust are arranged in a direction orthogonal to the vehicle traveling direction X. An outlet may be arranged. Specifically, the air inlet and the air outlet may be separately disposed on one and the other side surfaces of the cover body.

10, 10V Engine cover 11 Cover body 13 Bottom upper wall 14 Bottom wall 15 Air inlet 15H Hinge 16 Guide piece 17 Air outlet 20 Sound absorbing material 21 Internal guide slope 22 Rear end vertical surface 24 Triangular ridge (noise reduction projection) )
24V conical protrusion (noise reduction protrusion)
26 Block part 27 Helmholtz resonance room 28, 29 Noise inlet 30 Clearance 40 Movable lid 41 Bimetal (opening changing part)
90 Engine X Vehicle traveling direction

Claims (7)

A sound absorbing material (20) made of foamed resin is fixed inside the cover body (11) having a tray structure, and the sound absorbing material (20) is fixed to the vehicle in a state of being opposed to the engine (90) of the vehicle. In the engine cover (10, 10V)
An air inlet (15) formed in the cover body (11) for introducing external air into the cover body (11) to flow between the sound absorbing material (20) and the engine (90). )When,
An air discharge port (17) formed in the cover body (11) for discharging the air in the cover body (11) to the outside;
1 formed on the sound absorbing material (20) and opening toward the engine (90), and arranged so as to move back and forth in the direction of air flow from the air inlet (15) to the air outlet (17). A pair of noise inlets (28, 29);
It is formed inside the sound absorbing material (20) or between the sound absorbing material (20) and the cover body (11) so as to communicate between the pair of noise introduction ports (28, 29). An engine cover (10, 10V) comprising a Helmholtz resonance chamber (27) capable of reducing noise introduced from the pair of noise introduction ports (28, 29) by Helmholtz resonance. A plurality of noise reduction protrusions (24, 24V) are formed on a surface (23) of the sound absorbing material (20) facing the engine (90),
The air introduced into the cover main body (11) from the air introduction port (15) is configured to flow through the gap (30) between the noise reduction projections (24, 24V). The engine cover (10, 10V) according to claim 1, characterized in that The air inlet (15) and the air outlet (17) are arranged so as to move back and forth in the vehicle traveling direction (X),
The plurality of noise reduction protrusions (24) are a plurality of triangular protrusions (24) having a triangular cross-section extending in the vehicle traveling direction (X) and arranged side by side. The described engine cover (10, 10V).   The pair of noise introduction ports (28, 29) are formed so as to cross all or part of the plurality of triangular protrusions (24) at two intermediate positions in the longitudinal direction, and the sound absorbing material (20) Among the pair of noise inlets (28, 29) on the surface facing the engine (90), the block portion being close to or closely contacting the engine (90) from the plurality of triangular protrusions (24) The engine cover (10, 10V) according to claim 3, wherein (26) is provided. The air inlet (15) is disposed on the bottom wall (14) of the tray structure in the cover body (11),
The cover body (11) protrudes obliquely outward and forward from the opening edge on the rear side of the vehicle traveling direction (X) in the air introduction port (15) to the air introduction port (15) when the vehicle travels. The engine cover (10, 10V) according to any one of claims 1 to 4, wherein a guide piece (16) for guiding air is formed.   The sound absorbing material (20) includes an internal guide slope (21) that is inclined so as to gradually approach the engine (90) as it rises from the rear opening edge of the air introduction port (15) toward the rear. The engine cover (10, 10V) according to claim 5, characterized in that is formed. A movable lid (40) capable of changing the opening of the air inlet (15);
The heat of the engine (90) is thermally deformed and the opening of the air inlet (15) is increased as the temperature of the engine (90) is increased, while the temperature of the engine (90) is decreased as the temperature of the engine (90) is decreased. An opening degree changing part (41) for driving the movable lid (40) so as to reduce the opening degree of the air introduction port (15) is provided. The engine cover (10, 10V) described in the item.

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