JPH09195887A - Shield structure of fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a noise radiated from a fuel injection pump itself and a standing wave generated between the fuel injection pump and a cylinder block, by composing a shield member to cover the fuel injection pump by a noise insulating member to cover the noise generating face of the fuel injection pump, and a noise absorption member filled between the fuel injection pump and the cylinder block. SOLUTION: After a fuel injection pump 2A is installed to a cylinder block 1A, a first shield member 11 uses a heat resisting rubber at the lower and the upper sides of the rear surface of the fuel injection pump 2A, and it is formed of the rear side noise insulating members 11a and 11c fixed to the cylinder block 1A, and a rear side noise absorption member 11b formed by filling a foaming material to the part surrounded actually by the cylinder block 1A and the fuel injection pump 2A. And a second shield member 12 is formed of the front side noise insulating member 12a fixing the part not covered by the first shield member 11 by a clip and the like, and the front side noise absorption member 12b made by filling a synthetic resin at the space part surrounded by the first shield member 11, the front side noise insulating member 12a, and the fuel injection pump 2A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention occurs between noise emitted from the fuel injection pump itself, which accounts for a large proportion of engine noise, and between the fuel injection pump and the cylinder block of the engine. The present invention relates to an engine noise prevention device for reducing noise due to standing waves.

[0002]

2. Description of the Related Art Engine noise has been a problem in the past for manufacturing comfortable automobiles. The noise generated by the engine and the noise between the engine cylinder block and the fuel injection pump have been known as the noise. There are noise due to standing waves that are mutually amplified and noise emitted from the fuel injection pump itself, and these are collectively referred to as engine noise.

Recently, a method of reducing the engine noise in order to keep the inside of the vehicle quiet has been studied. Specifically, a noise prevention device shown in FIG. 8 has been proposed in Japanese Utility Model Publication No. 4-95631. As described above, the gap G between the cylinder block 1 and the fuel injection pump 2 is closed by the 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 device, even if the standing wave can be prevented, the 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.

Further, the noise prevention device shown in FIG.
As proposed in No. 95072, this device is provided with a casing 6 made of vibration-damping steel plate having a sound absorbing material 5 such as glass wool adhered to the inside of the front surface of the fuel injection pump 2. However, in this device, there is a gap g between the cylinder block 1 and the fuel injection pump 2, and a space portion 7 is also provided between the sound absorbing material 5 bonded to the casing 6 on the front surface and the fuel injection pump 2. Since it remains, noise due to the standing wave cannot be prevented, and noise emitted from the cylinder block 1 and noise emitted from the fuel injection pump 2 itself cannot be sufficiently prevented. Further, since metal is used for the casing 6, there is also a problem of secondary noise generation due to the vibration of the casing 6.

[0005]

SUMMARY OF THE INVENTION The present invention prevents noise emitted from the fuel injection pump itself and noise due to standing waves generated between the fuel injection pump and the cylinder block of the engine, and also prevents the cylinder block. It is intended to reduce some of the noise emitted from the.

[0006]

In order to solve the above problems, a surface of a fuel injection pump fixed to a side of a cylinder block of an engine with a gap is substantially covered with a shielding member. The shielding member provides a fuel injection pump shielding structure including a sound insulating material that covers a noise generating surface of the fuel injection pump and a sound absorbing material filled between the fuel injection pump and the sound insulating material.

The shield member preferably covers the entire surface without any gaps. For example, the operating portion, the pipe lead-out portion,
It substantially covers the fuel injection pump except for small openings and gaps such as windows for heat dissipation that are negligible for noise protection. 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.In particular, heat-resistant rubber is used, and the sound absorbing material absorbs noise from the sound source. It is preferable to use a foamed material of synthetic resin, which is a material having a property of attenuating inside thereof.

Further, in the above-mentioned shielding structure, a shielding member is disposed between the cylinder block and the fuel injection pump, and a surface of the fuel injection pump where the first shielding member is not disposed. A second shield member for covering is provided, and the first and second shield members provide a shield structure for the fuel injection pump that is separably formed on the surface of the fuel injection pump.

The first and second shield members are provided on the surface of the fuel injection pump so that the shield member can be easily disassembled, for example, to cover the back surface and the front surface of the fuel injection pump. Separable at the center. In this case, if the shielding members can be separated so that the surfaces required for adjustment, inspection, and maintenance are easily exposed together, the workability of forming, inspection, and adjustment is good.

Further, when the sound insulating material is brought into direct contact with the fuel injection pump in the vicinity of the separable portion, it is not necessary to make a cut in the sound absorbing material, and a member for closing the cut portion required when the foam material is filled. The process can be eliminated.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS.
A first embodiment of the present invention will be described. 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 it through the upper pipe 13b and the fuel injection nozzle, Inject fuel into.

As shown by the hatched portion in FIG. 7, the shielding members 11 and 12 of the present invention are the operating lever 15 and the pipe 13a.
The fuel injection pump 2A is substantially covered except for the arrangement portion such as 13b. With reference to FIG. 1 and FIG. 2, a method for forming the shielding members 11 and 12 of the present invention composed of the sound insulating materials 11a, 11c and 12a and the sound absorbing materials 11b and 12b will be described below.

First, in the first step, the cylinder block 1
After the fuel injection pump 2A is attached to A, the rear surface sound insulating material 11a made of heat resistant rubber is attached to the lower surface side of the rear surface of the fuel injection pump 2A by the bolts 16 or the like in the cylinder block 1A.
Fixed to the cylinder block 1A and the fuel injection pump 2
Back surface sound insulation material 11a that substantially covers the lower surface side of the gap with A
Attach. Then, a synthetic resin foam material is filled in a portion substantially surrounded by the back surface sound insulation material 11a, the cylinder block 1A, and the fuel injection pump 2A, and the back surface sound absorption material 1 is formed.
1b is formed. Since the back surface sound absorbing material 11b is formed by being filled, it can be formed without forming a small gap.

Further, a back surface sound insulation member 11a made of heat-resistant rubber is fixed to the cylinder block 1A with bolts 16 or the like on the upper surface side of the back surface of the fuel injection pump 2A, and a gap between the cylinder block 1A and the fuel injection pump 2A. The rear surface sound insulating material 11c that substantially covers the upper surface side of is attached. By this first step, it is possible to form the first shielding member 11 including the back surface sound insulating materials 11a and 11c and the back surface sound absorbing material 11b.

This foam material is filled with the sound insulating materials 11a, 11a.
With a structure in which a part of c is brought into direct contact with the surface of the fuel injection pump 2A, a member and a process for closing the gap are unnecessary, and the work of filling the foam material can be simplified. As a second step, after the first shielding member 11 is created, the front surface sound insulating material 12a is attached to the first shielding member 11 of the fuel injection pump 2A.
Clip 1 to substantially cover the surface not covered with
It is fixed by a method using 7 or a sheet fastener. Next, the space portion substantially surrounded by the first shielding member 11, the front surface sound insulating material 12a and the fuel injection pump 2A is filled with a synthetic resin foam material to form the rear surface sound absorbing material 12b. By this second step, the back surface sound absorbing material 12b and the front surface sound insulating material 1
It is possible to form the second shielding member 12 composed of 2a.

The second shield member 12 is an operating portion such as the lever 15 of the fuel injection pump 2A and the pipes 13a and 1a.
The injection pump 1A except for the portion 3b and the exclusion portion 18 which is opened as needed for heat dissipation and filling for filling the foam material.
Has a structure that substantially covers the surface of the. This excluded part 1
8 can also be provided on the first shielding member 11 side as required.

By these steps, the sound absorbing materials 11b, 12
A shielding structure that substantially covers the surface of the fuel injection pump 2A can be formed by the shielding members 11 and 12 configured by b and the sound insulating materials 11a, 11c, and 12a. The sound absorbing material 11b,
The filling step of 12b does not necessarily have to be performed only when the fuel injection pump 2A is attached to the cylinder block 1A of the engine. Sound insulation material 11
It is also possible to use a, 11c and 12a for molding.

These first and second shielding members 11 and 12
Is a surface of the fuel injection pump 2A, and the first shield member 11 and the second shield member 12 are configured to be separable and connectable by a clip 17 or a planar fastener (not shown). If this separable part is structured such that a part of the sound insulating material 12a is brought into direct contact with the surface of the fuel injection pump 2A, a gap is opened between the fuel injection pump 2A and the sound insulating materials 11a and 11c, and the sound absorbing material is formed. As compared with the case of disposing, the member and the process for closing the gap, which are required at the time of filling the foam material, are unnecessary, and the work of filling the foam material can be simplified. With regard to this separable structure, for example, the shielding members 11 and 12 are divided into a back surface portion and a front surface portion of the fuel injection pump 2 so that the fuel injection pump 2A can be easily formed, disassembled, and assembled. The surface part near the central part in the front-back direction is made separable.

At the time of this division, if the shielding member 12 is formed in such a shape that the surfaces of the fuel injection pump 2 that are particularly necessary for adjustment, inspection, and maintenance are collectively exposed, it will be necessary to perform adjustment, inspection, and maintenance work. Can be simplified. The first shielding member 11 and the second shielding member 12 do not necessarily have to be single, and have a structure that can be separated into a plurality of pieces as needed so that they can be easily formed, disassembled, and assembled. To do.

FIG. 3 and FIG. 4 show the second embodiment, in which the first shielding member 11 between the cylinder block 1A and the fuel injection pump 2A is the sound absorbing material 11b and the sound insulating material 11.
It has a sandwich structure such as a, 11c, and sound absorbing material 11b. With 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
Since the sound insulation members 11a and 11c can also be arranged on the back surface of the fuel injection pump 2, the noise prevention effect can be enhanced. This sandwich structure may also be used for the second shield member 12.

FIG. 5 is a graph showing the effect of preventing noise. The horizontal axis of the graph represents the engine speed, and the vertical axis represents the noise level measured in the vicinity of the engine on a scale of 2d.
The relative difference of B is shown. Line A shows the noise level near the engine without the shield structure, and line B shows the noise level with the shield structure of the present invention. Then, the shaded area C between the lines A and B is
It is the difference between the above two noise levels, and represents the noise prevention effect according to the present invention. As indicated by the area C in this graph, the present invention exerts a great effect of preventing noise, although there is a difference in the noise level reduction amount depending on the engine speed.

Therefore, according to the embodiment of the present invention described above, a high effect can be exhibited in preventing engine noise, and the sound absorbing material is easily formed by filling.
Furthermore, the front and rear shields can be separated into multiple parts for easy disassembly, so adjustment of the fuel injection pump
It is possible to provide a fuel injection pump shielding structure for preventing engine noise that facilitates inspection and maintenance work.

[0023]

According to the first aspect of the present invention, since the surface of the fuel injection pump is substantially covered with the shielding member composed of the sound absorbing material and the sound insulating material, the noise emitted from the fuel injection pump itself and the cylinder. Noise due to standing waves between the block and the fuel injection pump can be prevented. Further, since a part of the surface of the cylinder block can be covered with the shielding member, a part of noise emitted from the cylinder block can be prevented.

According to the second aspect of the present invention, since the heat-resistant rubber is used as the sound insulating material, the vibration propagating property thereof can damp the vibration propagating from the engine cylinder block and the fuel injection pump, thereby reducing noise. The next occurrence can be prevented. Also, by forming the sound absorbing material by filling it with a synthetic resin foam material, it is possible to prevent noise due to the sound absorbing characteristics of the foam material, and a standing wave is likely to occur between the cylinder block, the fuel injection pump, and the sound insulation material. Since it is possible to fill a large space without any gaps, it is possible to prevent the generation of noise due to standing waves. Further, since the work of molding the sound absorbing material is facilitated, the work efficiency in forming the shielding member is improved.

According to the third aspect of the present invention, since the shielding material can be separated into a plurality of pieces, the forming work is facilitated and the disassembling / assembling for adjustment / inspection / maintenance is facilitated. Especially when the divided shape of the shielding member is made into a shape that makes it easy to expose the parts required for adjustment, inspection, and maintenance, the number of shielding members required for disassembly is small, and workability of disassembly and assembly is further improved. 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 cross-sectional view showing the structure of the first embodiment.

FIG. 3 is a plan sectional view showing a 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 portion 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]

 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 First Shielding Member 11a, 11c Backside Sound Insulation Material 11b Rear 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 part

Claims (3)

[Claims] 1. A surface of a fuel injection pump fixed laterally of a cylinder block of an engine with a gap is substantially covered with a shielding member, and the shielding member covers a noise generating surface of the fuel injection pump. A shielding structure for a fuel injection pump, comprising a sound insulating material for covering and a sound absorbing material filled between the fuel injection pump and the sound insulating material. 2. The shielding structure for a fuel injection pump according to claim 1, wherein the sound insulating material forming the shielding member is a heat-resistant rubber, and the sound absorbing material is a foamed material of synthetic resin. 3. A first shielding member, wherein the shielding member is arranged between a cylinder block and the fuel injection pump,
The second shield member covers the surface of the fuel injection pump in which the first shield member is not arranged.
The shield structure for a fuel injection pump according to claim 1 or 2, wherein the second shield member and the second shield member are formed so as to be separable from each other on the surface of the fuel injection pump.