JP3796789B2 - Shielding structure of fuel injection pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to noise radiated from the fuel injection pump itself, which occupies a large proportion of engine noise, and noise caused by standing waves generated between the fuel injection pump and the engine cylinder block. The present invention relates to an engine noise prevention apparatus for reduction.
[0002]
[Prior art]
Engine noise has become a problem in order to produce a more comfortable automobile than before, but this noise is a constant that amplifies the noise generated by the engine and the noise between the engine cylinder block and the fuel injection pump. There are noise due to standing waves and noise radiated from the fuel injection pump itself, and these are combined into engine noise.
[0003]
Recently, in order to keep the interior of the vehicle quiet, a method for reducing the engine noise has been studied. Specifically, as shown in Japanese Utility Model Publication No. 4-95631, a noise prevention device shown in FIG. The gap G between the cylinder block 1 and the fuel injection pump 2 is closed by metal covers 4a and 4b attached to the side surface of the cylinder block 1 and the side surface of the fuel injection pump 2 via the sealing material 3 at the upper and lower portions. The closed gap G is filled with a sound absorbing material 5 such as glass wool. However, in this apparatus, even if the standing wave can be prevented, noise radiated from the fuel injection pump 2 itself cannot be prevented. There is also a problem of secondary generation of noise due to vibration of the metal covers 4a and 4b.
[0004]
9 has been proposed in Japanese Utility Model Laid-Open No. 3-95072. This device is made of a vibration-damping steel plate in which a sound absorbing material 5 such as glass wool is adhered to the front surface of the fuel injection pump 2 inside. The casing 6 is provided. However, in this apparatus, there is a gap g between the cylinder block 1 and the fuel injection pump 2, and there is also a space portion 7 between the sound absorbing material 5 bonded to the casing 6 on the front portion and the fuel injection pump 2. As a result, noise due to standing waves cannot be prevented, and noise radiated from the cylinder block 1 and noise radiated from the fuel injection pump 2 itself cannot be sufficiently prevented. Further, since metal is used for the casing 6, there is a problem of secondary generation of noise due to vibration of the casing 6.
[0005]
[Problems to be solved by the invention]
The present invention prevents noise radiated from the fuel injection pump itself and noise due to standing waves generated between the fuel injection pump and the engine cylinder block, and also eliminates part of the noise radiated from the cylinder block. It is intended to reduce.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the surface of the fuel injection pump fixed to the side of the cylinder block of the engine with a gap is substantially covered with a shielding member, and the shielding member is configured to generate noise of the fuel injection pump. a sound insulator which the generating surface covering, including the gap, filled with a foam of a substantially enclosed synthetic resin into the gap even space portion including between said fuel injection pump wherein the sound insulating member and the cylinder block And a first shielding member in which the shielding member is disposed between the cylinder block and the fuel injection pump, and the fuel injection in which the first shielding member is not disposed. The second shielding member that covers the surface of the pump is configured such that the first and second shielding members can be divided on the surface of the fuel injection pump, and the sound insulating material is directly attached to the fuel injection pump. surface Providing shielding structure of the fuel injection pump is mounted in contact.
[0007]
The shielding member preferably covers the entire surface without any gaps, but is substantially free of small openings and gaps that are negligible in terms of noise prevention, such as operation parts, piping outlets, and heat dissipation windows. Cover the fuel injection pump in a sense.
In this shielding structure, the sound insulating material that constitutes the shielding member is a material that does not generate vibration sound from itself and does not allow sound to pass through, especially heat-resistant rubber, and the sound absorbing material absorbs noise from the sound source. It is preferable to use a synthetic resin foam material, which is a material having a property of damping inside.
[0008]
Further, in the above shielding structure of the fuel injection pump, a first shielding member and the fuel injection pump the first shielding member is not arranged to said shielding member is disposed between said fuel injection pump and the cylinder block It is composed of a second shielding member covering the surface of these first and second shielding members being separable formed on the surface of the fuel injection pump, and the surface of the fuel injection pump of the sound insulation material A fuel injection pump shielding structure in which the sound insulation materials of the first and second shielding members are superimposed on each other at the attachment portion .
[0009]
The first and second shielding members are arranged at the center of the surface of the fuel injection pump so as to cover, for example, the back surface portion and the front surface portion of the surface of the fuel injection pump so that the shielding member can be easily disassembled. Make it separable. In this case, if the shielding member can be separated so that the surfaces necessary for adjustment, inspection, and maintenance can be easily exposed together, the workability of formation, inspection, and adjustment is good.
[0010]
In addition, when the sound insulating material is brought into direct contact with the fuel injection pump in the vicinity of the separable part, there is no need to make a cut in the sound absorbing material, and there is no need for a member and process for closing the necessary cut part when filling the foam material. Can be.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 6, the fuel injection pump 2A is fixed to the side of the cylinder block 1A of the engine 10, sucks fuel from the lower pipe 13a, pressurizes it, and passes through the upper pipe 13b and the fuel injection nozzle to the inside of the cylinder. Inject fuel into the tank.
[0012]
As shown by the hatched portion in FIG. 7, the shielding members 11 and 12 of the present invention substantially cover the fuel injection pump 2A except for the arrangement portions such as the operation lever 15 and the pipes 13a and 13b.
With reference to FIG. 1 and FIG. 2, the formation method of the shielding members 11 and 12 of this invention comprised by the sound insulation materials 11a, 11c, and 12a and the sound absorption materials 11b and 12b is demonstrated below.
[0013]
First, in the first step, after the fuel injection pump 2A is attached to the cylinder block 1A, the back surface sound insulating material 11a using heat-resistant rubber is attached to the cylinder block 1A using bolts 16 or the like on the lower surface side of the back surface of the fuel injection pump 2A. The back surface sound insulating material 11a that substantially covers the lower surface side of the gap between the cylinder block 1A and the fuel injection pump 2A is fixed. Next, a portion substantially surrounded by the back surface sound insulating material 11a, the cylinder block 1A, and the fuel injection pump 2A is filled with a synthetic resin foam material to form the back surface sound absorbing material 11b. Since the back surface sound-absorbing material 11b is formed by filling, it can be formed without leaving a small gap.
[0014]
Further, the back surface sound insulating material 11a using heat-resistant rubber is fixed to the cylinder block 1A with a bolt 16 or the like on the upper surface side of the back surface portion of the fuel injection pump 2A, and the upper surface side of the gap between the cylinder block 1A and the fuel injection pump 2A A back surface sound insulating material 11c that substantially covers is attached. By this first step, it is possible to form the first shielding member 11 composed of the back surface sound insulating materials 11a and 11c and the back surface sound absorbing material 11b.
[0015]
If the foam filling material has a structure in which a part of the sound insulating materials 11a and 11c is in direct contact with the surface of the fuel injection pump 2A, a member and a process for closing the gap become unnecessary, and the foam filling operation is simplified. Can be
As a second step, after the first shielding member 11 is created, the clip 17 is formed so that the front surface sound insulating material 12a substantially covers the surface of the fuel injection pump 2A that is not covered by the first shielding member 11. And fix it by a method using a surface fastener. Next, the back portion sound absorbing material 12b is formed by filling a space portion substantially surrounded by the first shielding member 11, the front surface sound insulating material 12a, and the fuel injection pump 2A with a synthetic resin foam material. By this second step, the second shielding member 12 composed of the back surface sound absorbing material 12b and the front surface sound insulating material 12a can be formed.
[0016]
The second shielding member 12 includes an operating portion such as the lever 15 of the fuel injection pump 2A and the pipes 13a and 13b, and an excluded portion 18 opened as necessary for heat dissipation and injection for filling with foam material. Except for this, the surface of the injection pump 1A is substantially covered. The exclusion portion 18 can be provided on the first shielding member 11 side as necessary.
[0017]
By these steps, a shielding structure that substantially covers the surface of the fuel injection pump 2A with the shielding members 11 and 12 including the sound absorbing materials 11b and 12b and the sound insulating materials 11a, 11c, and 12a can be formed.
The filling process of the sound absorbing materials 11b and 12b is not necessarily performed only at the time of attaching the fuel injection pump 2A to the cylinder block 1A of the engine. If there are molds having the same shape, the process is convenient. Accordingly, the mold and the sound insulating materials 11a, 11c, and 12a can be formed in advance.
[0018]
The first and second shielding members 11 and 12 are the surface of the fuel injection pump 2A, and the first shielding member 11 and the second shielding member 12 are separated by a clip 17 or a planar fastener (not shown). And connectable.
If the separable part is structured such that a part of the sound insulating material 12a is in direct contact with the surface of the fuel injection pump 2A, a gap is formed between the fuel injection pump 2A and the sound insulating materials 11a and 11c, and the sound absorbing material is obtained. Compared with the case where the material is disposed, a member and a process for closing the gap required when filling the foam material are not required, and the filling operation of the foam material can be simplified.
With regard to this separable configuration, for example, the fuel injection pump 2A is formed so that the shielding members 11 and 12 can be divided into a back surface portion and a front surface portion of the fuel injection pump 2 and can be easily formed, disassembled and assembled. It is made separable at the surface portion near the center in the front-rear direction.
[0019]
In this division, if the shielding member 12 is formed in a shape that makes it easy to expose the surface of the fuel injection pump 2 that is particularly necessary for adjustment, inspection, and maintenance, the work for adjustment, inspection, and maintenance is simplified. I can do it.
The first shielding member 11 and the second shielding member 12 do not necessarily have to be single, and can be separated into a plurality of parts as necessary so that formation, disassembly, and assembly are easy. To do.
[0020]
3 and 4 show a second embodiment. The first shielding member 11 between the cylinder block 1A and the fuel injection pump 2A serves as a sound absorbing material 11b, sound insulating materials 11a and 11c, and a sound absorbing material 11b. Thus, it is configured with a sandwich structure. By adopting such a sandwich structure, the effect of holding the sound absorbing material 11b is enhanced by the sound insulating materials 11a and 11c having high rigidity, and the sound insulating materials 11a and 11c can be arranged also on the back surface of the fuel injection pump 2, so that noise is generated. The prevention effect can also be enhanced. This sandwich structure may also be used for the second shielding member 12.
[0021]
FIG. 5 is a graph showing the effect of noise prevention. The horizontal axis of the graph shows the engine speed, and the vertical axis shows the noise level measured close to the engine by a relative difference of 1 scale 2 dB. .
Line A shows the noise level when the shielding structure is not provided at a location close to the engine, and line B shows the noise level when the shielding structure of the present invention is provided. A hatched area C between the two lines A and B is the difference between the two noise levels and represents the noise prevention effect of the present invention. As shown in region C of this graph, the present invention has a great noise prevention effect although there is a difference in the amount of noise level reduction depending on the engine speed.
[0022]
Therefore, according to the embodiment of the present invention described above, it is possible to exert a high effect on the prevention of engine noise, and the formation of the sound absorbing material is easy because it is performed by filling. The fuel injection pump shielding structure can be provided to prevent engine noise and to facilitate adjustment, inspection and maintenance of the fuel injection pump because it can be separated into a plurality of parts for easy disassembly.
[0023]
【The invention's effect】
According to the first aspect of the present invention, since the surface of the fuel injection pump is substantially covered with a shielding member composed of a sound absorbing material and a sound insulating material including a gap with the side of the cylinder block, radiation from the fuel injection pump itself. Noise and noise caused by standing waves between the cylinder block and the fuel injection pump can be prevented. Furthermore, since a part of the surface of the cylinder block can be covered with the shielding member, part of the noise radiated from the cylinder block can be prevented.
Also, by forming the sound absorbing material by filling the synthetic resin foam material, noise can be prevented by the sound absorbing characteristics of the foam material, and standing waves between the cylinder block, the fuel injection pump and the sound insulating material are likely to occur. Since it is possible to fill a large space without any gaps, it is possible to prevent the occurrence of noise due to standing waves. Furthermore, since the work of forming the sound absorbing material is facilitated, the work efficiency when forming the sound insulating member is improved.
[0024]
According to the invention of claim 2, since heat-resistant rubber is used as a sound insulating material, the vibration propagating from the engine cylinder block and the fuel injection pump can be attenuated by the damping characteristic against the vibration, and secondary generation of noise is generated. Can be prevented .
[0025]
In the invention of claim 3, since the shielding material can be separated into a plurality of parts, the forming operation is facilitated, and the disassembly / assembly for adjustment, inspection, and maintenance is facilitated. In particular, when the divided shape of the shielding member is adjusted so that the parts necessary for adjustment, inspection, and maintenance can be easily exposed, the number of shielding members required for disassembly is reduced, and the workability of disassembly and assembly is further reduced. It can be improved.
[Brief description of the drawings]
FIG. 1 is a plan sectional view showing a structure of a first embodiment.
FIG. 2 is a side sectional view showing the structure of the first embodiment.
FIG. 3 is a plan sectional view showing the structure of a second embodiment.
FIG. 4 is a side sectional view showing the structure of the second embodiment.
FIG. 5 is a graph showing a noise reduction effect.
FIG. 6 is a perspective view showing an injection pump mounting position.
FIG. 7 is a perspective view showing a shielding part of the injection pump.
FIG. 8 is a side sectional view showing a structure of a conventional embodiment.
FIG. 9 is a side sectional view showing a structure of a conventional embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1A Cylinder block 2, 2A Fuel injection pump 3 Sealing material 4a, 4b Metal cover 5 Sound absorbing material 6 Casing 7 Space part 8 Rubber 9a Upper stay 9b Lower stay 10 Engine 11 1st shielding member 11a, 11c Back surface sound insulation Material 11b Back surface sound absorbing material 12 Second shielding member 12a Front surface sound insulating material 12b Front surface sound absorbing material 13a, 13b Piping 15 Lever 16 Bolt 17 Clip 18 Excluded portion

Claims (3)

The surface of the fuel injection pump fixed to the side of the cylinder block of the engine with a gap is substantially covered with a shielding member, and the shielding member includes a noise generation surface of the fuel injection pump including the gap. composed of a sound insulation material covering, and the fuel injection pump and said sound insulator and the cylinder block and in a substantially enclosed sound absorbing material formed by filling a foaming material of a synthetic resin into the gap also including spatial portion And a second shielding member covering the surface of the fuel injection pump where the first shielding member is not disposed, and the shielding member is disposed between the cylinder block and the fuel injection pump. is composed of the shielding member, the first of these and the second shielding member, to be divided by the surface of the fuel injection pump, and the sound insulating member is attached in contact with the direct surface of the fuel injection pump Shielding structure of the fuel injection pump. Shielding structure of the fuel injection pump according to claim 1, wherein the sound insulating material forming the shielding member is made up of heat-resistant rubber. Configuration in a second shielding member covering the first shielding member disposed, the surface of the first said fuel injection pump shielding member is not disposed in between the shielding member and the cylinder block and the fuel injection pump The first and second shielding members are formed to be separable on the surface of the fuel injection pump , and the first and second shielding members are attached to the surface of the fuel injection pump by the sound insulating material. The fuel injection pump shielding structure according to claim 1 or 2 , wherein the sound insulation material of the second shielding member is superposed .

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