Engine vibration reduction structure

Abstract

To provide an engine vibration reduction structure which can reduce, while suppressing increase of weight of a vehicle, engine vibration and engine noise.SOLUTION: A heat exchanger 30, which is for raising a temperature of a battery of a vehicle 10 being a plug-in hybrid electric vehicle is disposed away from a vehicle-upper side of an engine mount 20. Further, a first bracket 40 is disposed on a front side in a vehicle front-rear direction with respect to the heat exchanger 30 in a vehicle plan view to couple the heat exchanger 30 and the engine mount 20, meanwhile, a second bracket 50 is disposed on a rear side in the vehicle front-rear direction with respect to the heat exchanger 30 in the vehicle plan view to couple the heat exchanger 30 and the engine mount 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an engine vibration reduction structure. [Background technology]

[0002] Patent Document 1 below discloses technology related to a structure for reducing vibration in an engine mount member. Simply put, this prior art technology reduces vibration or vibration noise transmitted to the vehicle body by attaching a mass damper and a dynamic damper to the engine mount member using the same mounting fixture. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-270699 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in this prior art, the mass of the vehicle increases by the amount of the mass damper and the dynamic damper that are attached.

[0005] In consideration of the above, an object of the present invention is to provide an engine vibration reducing structure that can reduce engine vibration and engine noise while suppressing an increase in the mass of a vehicle. [Means for solving the problem]

[0006] The engine vibration reduction structure of the first aspect is intended to heat the battery of a plug-in hybrid vehicle and has a heat exchanger arranged at a distance above the vehicle from the engine mount, a first bracket arranged on one side of the heat exchanger in a plan view of the vehicle and connecting the heat exchanger to the engine mount, and a second bracket arranged on the other side of the heat exchanger opposite the one side in a plan view of the vehicle and connecting the heat exchanger to the engine mount.

[0007] According to a first aspect of the engine vibration reduction structure, a heat exchanger for heating the battery of a plug-in hybrid vehicle is disposed above the engine mount at a distance from the vehicle. A first bracket is disposed on one side of the heat exchanger in a plan view of the vehicle, connecting the heat exchanger to the engine mount. A second bracket is disposed on the other side of the heat exchanger, opposite the one side in a plan view of the vehicle, connecting the heat exchanger to the engine mount. This allows for coupled resonance between the engine mount and the heat exchanger connected to the engine mount by the first and second brackets to occur in a desired frequency band, thereby achieving a favorable vibration reduction effect. Furthermore, because the heat exchanger is mounted for heating the battery of the plug-in hybrid vehicle and is not separately mounted to reduce engine vibration and engine noise, an increase in vehicle mass can be suppressed.

[0008] The engine vibration reducing structure of the second aspect is the engine vibration reducing structure of the first aspect, wherein ribs are formed on the inner surface side of the housing of the heat exchanger.

[0009] According to the second aspect of the engine vibration reduction structure, the ribs formed on the inner surface of the heat exchanger housing suppress elastic deformation of the wall surface of the heat exchanger housing during vibration, which makes it easy to set the natural frequency of the heat exchanger to a frequency band that contributes to reducing engine vibration. [Effects of the Invention]

[0010] As described above, the engine vibration reducing structure according to the present invention has the excellent effect of being able to reduce engine vibration and engine noise while suppressing an increase in the vehicle mass. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an engine vibration reduction structure according to an embodiment of the present invention, as viewed from the diagonally front right side of a vehicle. [Figure 2] 1 is a perspective view showing an engine vibration reduction structure according to an embodiment of the present invention, as viewed from the left rear side of a vehicle. [Figure 3] 2 is a diagram schematically showing a vehicle to which the engine vibration reducing structure of FIG. 1 is applied. FIG. [Figure 4] 4 is a graph showing vibration characteristics of the engine vibration reduction structure according to the embodiment and a comparative structure. [Figure 5] FIG. 2 is a perspective view showing the first comparative structure as viewed diagonally from the front right side of the vehicle. [Figure 6] FIG. 10 is a perspective view showing the second comparative structure as viewed from the diagonally front right side of the vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0012] An engine vibration reducing structure according to one embodiment of the present invention will be described with reference to Figures 1 to 6. In Figures 1 to 3, 5 and 6, arrow FR indicates the front side of the vehicle, arrow UP indicates the upper side of the vehicle, and arrow RH indicates the right side of the vehicle.

[0013] 3 is a schematic diagram of a vehicle 10 to which the engine vibration reduction structure according to this embodiment is applied. The vehicle 10 is a plug-in hybrid vehicle (PHEV (Plug-in Hybrid Electric Vehicle)). The vehicle 10 is provided with an engine 12 at the front of the vehicle. Note that the engine 12 is fastened to the vehicle body via engine mounts at multiple locations in addition to those described below, but a description of the fastening at these locations will be omitted.

[0014] Fig. 1 shows a perspective view of an engine vibration reduction structure provided on a vehicle 10 as seen from the diagonally forward right side of the vehicle, and Fig. 2 shows a perspective view of the engine vibration reduction structure provided on a vehicle 10 as seen from the diagonally rear left side of the vehicle. The components shown in Figs. 1 and 2 are components for fastening the right side of an engine 12 (see Fig. 3) to the vehicle body.

[0015] As shown in Figures 1 and 2, the engine mount 20 is attached to a front side member 14 (shown simply in the figures) via an engine mount bracket 18. The front side member 14 is a vehicle frame member that extends in the longitudinal direction of the vehicle on the side of the front of the vehicle. The engine mount bracket 18 is fixed to the upper surface of the front side member 14 by fastening, for example, using a bolt B1. A front base portion 18A is formed in a convex shape toward the upper side of the vehicle at the front of the engine mount bracket 18, and a rear base portion 18B is formed in a convex shape toward the upper side of the vehicle at the rear of the engine mount bracket 18.

[0016] The engine mount 20 includes a cylindrical tubular portion 22 with a rubber member 21 attached to the inside, a front leg 23 welded to the front side of the tubular portion 22, a rear leg 24 welded to the rear side of the tubular portion 22, an arm-attached ring body 25 welded to the upper end opening of the tubular portion 22 without closing the opening as shown in Fig. 2, and an inverted U-shaped curved plate portion 26 welded to the upper surface of a base end 25A of the arm-attached ring body 25. In the engine mount 20, a nut 27 (shown simply in the figure) is fixed to the rubber member 21 attached to the inside of the tubular portion 22, and the nut 27 protrudes above the rubber member 21.

[0017] As shown in FIG. 1 , the front leg 23 extends from a portion adjacent to the front of the tubular portion 22 toward the front base portion 18A of the engine mount bracket 18 and is bent in a generally U-shape so that the front or upper side of the vehicle is open. The front leg 23 includes a fixed portion 23A that overlaps the upper surface of the front base portion 18A of the engine mount bracket 18 and side portions 23B and 23C formed on both sides in the width direction (left-right direction). The fixed portion 23A of the front leg 23 is fastened to the front base portion 18A of the engine mount bracket 18 with a bolt B2. An attachment member 28 is welded to the upper surface of the right side portion 23B facing the right side of the vehicle. The attachment member 28 includes an attachment portion 28A bent and extended toward the right side of the vehicle at its upper end, and a rib 28B is formed to increase the rigidity of the bent portion. The attachment partner of the attachment member 28 will be described later.

[0018] 2, rear leg 24 extends from a portion adjacent to the rear side of tubular portion 22 toward rear base portion 18B of engine mount bracket 18 and is bent into a substantially U-shape so that the rear side and the upper side of the vehicle are open, and includes fixed portion 24A that is superimposed on the upper surface of rear base portion 18B of engine mount bracket 18, and side portions 24B, 24C formed on both sides in the width direction (left and right direction). Fixed portion 24A of rear leg 24 is fastened to rear base portion 18B of engine mount bracket 18 with bolt B3.

[0019] As shown in Fig. 1, the base end 25A of the armed ring body 25 is formed in a ring shape along the upper end opening of the tubular portion 22. The lower end of the front wall portion 26F of the curved plate portion 26 is welded to a portion of the front portion 25F of the armed ring body 25 in the vehicle longitudinal direction. Also, as shown in Fig. 2, the lower end of the rear wall portion 26R of the curved plate portion 26 is welded to a portion of the rear portion 25R of the armed ring body 25 in the vehicle longitudinal direction.

[0020] 1, armed ring body 25 has arm portion 25B extending obliquely upward and to the right of the vehicle from base end portion 25A. A bolt fastening hole 25H is formed in the tip end portion of arm portion 25B in the extension direction. The tip end portion of arm portion 25B in the extension direction is fastened to an apron (not shown) that constitutes a part of the vehicle body using a bolt (not shown, the central axis of the bolt is indicated by a dashed dotted line J1) that passes through bolt fastening hole 25H.

[0021] As shown in FIG. 2, the curved plate portion 26 provided on the upper side of the arm-attached ring body 25 is formed in an inverted U-shape when viewed in the vehicle width direction. A bolt insertion hole 26H is formed through the upper wall portion 26A of the curved plate portion 26. An engine bracket 60 is disposed below the upper wall portion 26A of the curved plate portion 26 and above the nut 27. The engine bracket 60 is a member fixed to the engine (not shown) and protrudes toward the engine mount 20. Note that in FIG. 2, only a portion of the engine bracket 60 is shown by a two-dot chain line for simplification. Also, the engine bracket 60 is not shown in FIG. 1. As shown in FIG. 2, a bolt B4 is inserted from above into the bolt insertion hole 26H formed in the upper wall portion 26A of the curved plate portion 26. This bolt B4 passes through the upper wall portion 26A of the curved plate portion 26 and the engine bracket 60 and is screwed into the nut 27.

[0022] Meanwhile, a heat exchanger 30 is disposed above the vehicle and spaced apart from the engine mount 20. The heat exchanger 30 is used to raise the temperature of the battery 16 (see FIG. 3) of the vehicle 10, which is a plug-in hybrid vehicle, and contributes to improving the rapid charging performance of the battery 16 in low-temperature environments. Additionally, the heat exchanger 30 is a water-to-water heat exchanger that is linked to the air conditioning system and is installed as standard on the vehicle 10, which is a plug-in hybrid vehicle. Two pipes Pa and Pb are connected to the heat exchanger 30 at the rear side in the vehicle's longitudinal direction, and these two pipes Pa and Pb allow water to flow in and out of the heat exchanger 30.

[0023] The heat exchanger 30 includes a substantially box-shaped housing 32. Ribs 38 are formed on the inner surface of the housing 32 of the heat exchanger 30. The ribs 38 are formed in a lattice pattern, for example. The area in which the ribs 38 are formed can be set as appropriate, but in this embodiment, for example, the ribs 38 are formed over the entire inner surface of the housing 32.

[0024] The heat exchanger 30 also includes a front panel 34 that forms the front surface in the vehicle longitudinal direction as shown in Fig. 1, and a rear panel 36 that forms the rear surface in the vehicle longitudinal direction as shown in Fig. 2. As shown in Fig. 1, the front panel 34 includes an upper protruding piece 34A that protrudes upward. As shown in Fig. 2, the rear panel 36 includes an upper protruding piece 36A that protrudes upward.

[0025] 1 in a plan view of the vehicle, a first bracket 40 that connects the heat exchanger 30 to the engine mount 20 is disposed on the front side (one side in a plan view of the vehicle) of the heat exchanger 30. As an example, the first bracket 40 is configured by connecting an upper component 42 that forms the upper side and a lower component 44 that forms the lower side. The upper component 42 and the lower component 44 are both bent plate-shaped members made of metal (steel, for example).

[0026] The upper component 42 of the first bracket 40 is overlapped with the front panel 34 at a portion including the upper protruding piece 34A, and is fastened with bolts B5 to the upper and lower portions of the upper protruding piece 34A and the left end of the front panel 34 in the vehicle left-right direction. The lower end position of the upper component 42 is at the same vertical position as the lower end position of the front panel 34. The upper component 42 also has a protruding portion 42A that is bent from its lower end toward the front of the vehicle. The first bracket 40 is fastened with bolts B6, with the protruding portion 42A of the upper component 42 overlapping the upper end portion 44A of the lower component 44.

[0027] The lower component 44 is bent and hangs down from the right end of the upper end 44A in the vehicle left-right direction, and the hanging portion 44B is disposed so that its plate thickness direction is along the vehicle width direction. The lower component 44 also has a protruding portion 44C that is bent and hangs down from the lower end of the hanging portion 44B to the right in the vehicle left-right direction. The protruding portion 44C overlaps the mounting portion 28A of the mounting member 28 and is fastened with bolt B7. Note that, in the first bracket 40, the position where the protruding portion 44C of the lower component 44 is fastened to the mounting member 28 of the engine mount 20 with bolt B7 is located further forward of the position where the upper component 42 is fastened to the heat exchanger 30 with bolt B5.

[0028] 2 in the vehicle front-rear direction (the other side opposite to the one side in the vehicle plan view), a second bracket 50 that connects the heat exchanger 30 and the engine mount 20 is disposed. As an example, the second bracket 50 is configured by connecting an upper component 52 that forms the upper side and a lower component 54 that forms the lower side. The upper component 52 and the lower component 54 are both bent plate-shaped members made of metal (steel, for example).

[0029] The upper component 52 of the second bracket 50 is overlapped with the rear panel 36 at a portion including the upper protruding piece 36A, and is fastened with bolts B8 to the upper and lower portions of the upper protruding piece 36A and the left end of the rear panel 36 in the vehicle left-right direction. The lower end position of the upper component 52 is at the same vertical position as the lower end position of the rear panel 36. The upper component 52 also has a protruding portion 52A that is bent from its lower end toward the rear of the vehicle and protrudes. The second bracket 50 is fastened with bolts B9 so that the protruding portion 52A of the upper component 52 is overlapped with the upper end 54A of the lower component 54.

[0030] The lower component 54 is bent and hangs down from the rear end of the upper end 54A in the vehicle front-rear direction, and the hanging portion 54B is disposed so that its plate thickness direction is along the vehicle front-rear direction. Also, as shown in FIG. 1 , a portion of the hanging portion 54B on the right side in the vehicle left-right direction is folded back to form a return portion 54C that sandwiches the rear wall portion 26R of the curved plate portion 26, and this return portion 54C is joined to the rear wall portion 26R of the curved plate portion 26 by welding. In the second bracket 50, the position at which the return portion 54C of the lower component 54 is joined to the curved plate portion 26 of the engine mount 20 is located rearward of the position at which the upper component 52 shown in FIG. 2 is fastened to the heat exchanger 30 with bolt B8.

[0031] As described above, the first bracket 40, the second bracket 50 and the heat exchanger 30 generate a relatively large moment when the engine mount 20 is in a mode in which it tilts left or right.

[0032] Next, the operation and effects of this embodiment will be described.

[0033] In this embodiment, a heat exchanger 30 for heating a battery 16 (see FIG. 3 ) of a vehicle 10, which is a plug-in hybrid vehicle, is disposed above the vehicle at a distance from the engine mount 20. A first bracket 40 shown in FIG. 1 is disposed on the front side of the heat exchanger 30 in the longitudinal direction of the vehicle (one side in the plan view of the vehicle) in a plan view of the vehicle to connect the heat exchanger 30 to the engine mount 20, and a second bracket 50 shown in FIG. 2 is disposed on the rear side of the heat exchanger 30 in the longitudinal direction of the vehicle (the other side opposite the one side in the plan view of the vehicle) in a plan view of the vehicle to connect the heat exchanger 30 to the engine mount 20. This allows coupled resonance between the engine mount 20 and the heat exchanger 30 connected to the engine mount 20 by the first bracket 40 and the second bracket 50 to occur in a desired frequency band, thereby achieving a favorable vibration reduction effect (a desired dynamic damper effect). Furthermore, the heat exchanger 30 is installed to heat the battery 16 (see FIG. 3) of the vehicle 10, which is a plug-in hybrid vehicle, and is not installed separately to reduce engine vibration and engine noise, which makes it possible to suppress an increase in the mass of the vehicle 10.

[0034] In addition, in this embodiment, ribs 38 are formed on the inner surface of the housing 32 of the heat exchanger 30, which reduces elastic deformation of the wall surface of the housing 32 of the heat exchanger 30 during vibration. This makes it possible to easily set the natural frequency of the heat exchanger 30 to a frequency band that contributes to reducing engine vibration.

[0035] Here, the effects of this embodiment will be further explained by comparing it with a first comparative structure 70 shown in Fig. 5 and a second comparative structure 80 shown in Fig. 6. For convenience, components in the first comparative structure 70 shown in Fig. 5 and the second comparative structure 80 shown in Fig. 6 that are substantially similar to those of this embodiment will be denoted by the same reference numerals.

[0036] A first comparative structure 70 shown in Fig. 5 has a structure in which a weight (mass damper) 72 is fixed to the engine mount 20 instead of the first bracket 40, the second bracket 50, and the heat exchanger 30 (see Figs. 1 and 2) of the present embodiment. A plurality of mounting members 74 are fixed to the weight 72, and each of the plurality of mounting members 74 is fixed to the curved plate portion 26. For convenience, the bolts B2 and B4 and the nuts 27 shown in Fig. 2 are not shown in Fig. 5.

[0037] A second comparative structure 80 shown in FIG. 6 includes a front bracket 82 instead of the first bracket 40 (see FIG. 1) of the present embodiment, but does not include the second bracket 50 (see FIG. 2) of the present embodiment. The front bracket 82 is made of steel and formed into a bent plate shape. It is fastened to the front panel 35 of the heat exchanger 30 at multiple locations on the left end and at the bottom with bolts (not shown). The front bracket 82 includes a protruding portion 82A at its lower end that is bent toward the front of the vehicle. The protruding portion 82A is fastened by a bolt (not shown) to a steel mounting member 84 welded to the right side of the front wall portion 26F of the curved plate portion 26 in the vehicle left-right direction. For convenience, bolts B1, B2, and B4, rubber member 21, and nut 27 shown in at least one of FIGS. 1 and 2 are not shown in FIG. 6.

[0038] Fig. 4 is a graph showing the relationship between vibration frequency and vibration level (excitation point inertance) during lateral vibration in the engine vibration reduction structure according to the embodiment and a comparative structure. The dotted line in the graph of Fig. 4 shows the characteristics of the comparative structure before countermeasures were taken, in which the first bracket 40, the second bracket 50, and the heat exchanger 30 (see Figs. 1 and 2) have been removed from the engine vibration reduction structure according to the embodiment. In the graph of Fig. 4, the two-dot chain line shows the characteristics of the first comparative structure 70 (see Fig. 5), the one-dot chain line shows the characteristics of the second comparative structure 80 (see Fig. 6), and the solid line shows the characteristics of the engine vibration reduction structure according to the embodiment.

[0039] 4, in the case of the first comparison structure 70 (see the two-dot chain line), the position of the vibration level peak P1 is shifted slightly to the left and slightly lower in the graph compared to the position of peak P0 in the comparison structure before the countermeasure was taken (see the dotted line), but only the effect as a mass damper is obtained. In the case of the second comparison structure 80 (see the one-dot chain line), the vibration level peak P2 is slightly lower, but the effect as a dynamic damper is small due to the low rigidity of the connection between the engine mount 20 and the heat exchanger 30.

[0040] In contrast, in the case of the engine vibration reduction structure of this embodiment (see solid line), coupled resonances P3 and P4 between the engine mount 20 and the heat exchanger 30 connected to the engine mount 20 by the first bracket 40 and the second bracket 50 occur at frequencies slightly lower and slightly higher than the frequency at peak P0 in the comparison structure before the countermeasures were taken (see dotted line), and the vibration levels of these coupled resonances P3 and P4 are lower than the vibration level of peak P0.Furthermore, an anti-resonance (see the part indicated by arrow A) occurs between these two coupled resonances P3 and P4, thereby effectively reducing the vibration level in the frequency band where the vibration level is desired to be reduced.

[0041] As described above, the engine vibration reducing structure according to this embodiment shown in FIGS. 1 and 2 makes it possible to reduce engine vibration and engine noise while suppressing an increase in the vehicle mass.

[0042] As a variation of the above embodiment, for example, in a structure including an engine mount provided on the rear side of the engine (12) in the vehicle longitudinal direction, the heat exchanger (30) is arranged spaced apart above the engine mount, a first bracket is arranged on the left side of the heat exchanger (30) in the vehicle transverse direction (one side in the vehicle plan view) relative to the heat exchanger (30) in the vehicle plan view to connect the heat exchanger (30) to the engine mount, and a second bracket is arranged on the right side of the heat exchanger (30) in the vehicle transverse direction (the other side opposite to the one side in the vehicle plan view) to connect the heat exchanger (30) to the engine mount.

[0043] In the above embodiment, the first bracket 40 is formed by connecting an upper component 42 and a lower component 44, but as a modification of the above embodiment, the first bracket may be formed by a single component. In the above embodiment, the second bracket 50 is formed by connecting an upper component 52 and a lower component 54, but as a modification of the above embodiment, the second bracket may be formed by a single component.

[0044] In addition, in the above embodiment, ribs 38 are formed on the inner surface of the housing 32 of the heat exchanger 30, and this configuration is preferable, but as a variation of the above embodiment, a configuration in which ribs are not formed on the inner surface of the housing of the heat exchanger may also be adopted depending on the material of the housing of the heat exchanger, etc.

[0045] The above-described embodiment and the above-described modifications can be implemented in appropriate combinations.

[0046] Although one example of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be implemented in various modified forms within the scope of the gist of the present invention. [Explanation of symbols]

[0047] 10 vehicles (plug-in hybrid vehicles) 16 Battery 20 Engine mount 30 heat exchanger 32 Heat exchanger housing 38 Ribs 40 First Bracket 50 Second bracket

Claims

1. a heat exchanger for heating a battery of a plug-in hybrid vehicle, the heat exchanger being disposed above the engine mount and spaced apart from the vehicle; a first bracket disposed on one side of the heat exchanger in a plan view of the vehicle and connecting the heat exchanger and the engine mount; a second bracket disposed on the other side of the heat exchanger opposite to the one side in a plan view of the vehicle and connecting the heat exchanger and the engine mount; Engine vibration reduction structure.

2. 2. The engine vibration reduction structure according to claim 1, wherein a rib is formed on the inner surface of the housing of the heat exchanger.

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