DE102008042626A1 - High-pressure fuel pump - Google Patents

Abstract

The present invention relates to a high pressure fuel pump (20) for a fuel injection system of an internal combustion engine (10) having a pump housing (32) comprising a flange (38) for attachment to the internal combustion engine (10). In the area between the flange (38) and the internal combustion engine (10), a vibration-damping layer (50) is arranged.

Description

State of the art

The The invention relates to a high-pressure fuel pump for a Fuel injection system of an internal combustion engine according to the preamble of claim 1.

During operation of a high-pressure fuel pump, pressure fluctuations (pulsations) occur in principle in a low-pressure region of the high-pressure fuel pump. In addition, for example, arises when operating a quantity control valve structure-borne noise. The pulsations (fluid sound) and the generated structure-borne noise generate vibrations in the entire audible frequency range, which is transmitted via the flange of the high-pressure fuel pump to a mounting structure of the internal combustion engine. These vibrations also lead to increased vibration load of different components of the internal combustion engine. From the DE 10 2005 033 634 A1 is a high-pressure fuel pump for a fuel injection system of an internal combustion engine is known, which is compact and operates with high efficiency. The resulting during operation of the high pressure fuel pump pulsations in the low pressure region of the high-pressure fuel pump are partially attenuated using a arranged under a pump cover pressure damper.

Disclosure of the invention

task the invention is to develop a high pressure fuel pump so that the high-pressure fuel pump with a low cost one quiet operation guaranteed.

to Solution of the task is a high-pressure fuel pump proposed with the features of claim 1. For the Invention important features can be further found in the following description and in the drawings, the features being both alone as well as in different combinations for the invention can be important without being explicit on each one is pointed out. Advantageous developments are also found in the subclaims.

By the vibration-damping layer will have vibrations that in the high-pressure fuel pump (pulsations) are generated in Direction of the internal combustion engine damped; as well will the transmission of vibrations from the internal combustion engine reduced to the high-pressure fuel pump. The present invention leads to a noise reduction and lowers the vibration or vibration load of the affected components. The reduction in structure-borne sound transmission also lowers a by the structure-borne noise excited airborne sound radiation from the cultivation structure. In addition, the vibration-damping Layer as a side effect in a suitable design as a seal between the high pressure fuel pump and the mounting structure of the Internal combustion engine and, for example, the outlet of engine oil or prevent fuel. The insertion of the vibration damping layer on the flange during assembly is easy to implement, which has a positive effect on the costs. In addition requires the vibration damping layer virtually no additional Space. Despite the use of the vibration-damping layer may be the relatively stiff connection of the high-pressure fuel pump be maintained on the internal combustion engine, which on the one hand the Life of both the high pressure pump and the attachment and on the other hand the efficiency (no tilting of the high-pressure pump) benefits.

Further It is suggested that the flange has mounting screws is attached to the internal combustion engine and between the screw heads the mounting screws and the flange a vibration damping Layer is arranged. This takes into account that besides a bearing surface of the flange on the mounting structure the engine transmitted vibrations via the mounting screws become. Due to the vibration-damping layer under the Screw heads this is prevented or greatly reduced.

Further it is suggested that the vibration damping layer a viscoelastic material. Called viscoelastic one polymers (high molecular weight elastic plastics such as. Polyurethanes, elastomers, plastomers, thermoplastics or silicones) with special elastic properties. The properties outside in the way, as would the elasticity solid body with liquid-like Connect behavior. Under dynamic stress becomes a part the deformation work is absorbed by the viscoelastic material, while another part is dissipated (transformed). In selecting a suitable polymer are further requirements, For example, after temperature resistance and after a chemical Resistance to ambient media (eg oil, fuel) to take into account. In this training is so the transferred structure-borne sound efficiency efficiently Due to the viscoelastic material damping partially in Viscoelastic material absorbed and partially dissipated. The at the transition point from the flange of the high-pressure fuel pump can be transmitted to the mounting structure vibrations thus be reduced particularly effectively.

Advantageously, a damping element which has at least one metallic sheet, wherein at least on one side of the sheet, the vibration-damping layer is arranged. The damping element (so-called "sandwich" or "compound" sheets) is disc-shaped and serves as a support for the flange of the high-pressure fuel pump, which is mounted on the mounting structure. On the metallic sheet, a thin viscoelastic layer is laminated.

additional is suggested that the damping element at least a metallic sheet comprising, on both sides, a vibration damping Layer has. Double-sided lamination of the viscoelastic Layer leads to an increase in viscoelastic Properties of the damping element. The metallic sheet It has a stabilizing effect, so that the elasticity of the Attaching the high pressure fuel pump by the viscoelastic Layer only slightly increases and all functional requirements (no tilting of the pump) and strength requirements (load the mounting screws) are still met. Production the disc-shaped damping elements takes place essentially by trimming just executed Sheets on which the viscoelastic layer (s) are already laminated is. The properties of the damping element can by the choice of the thickness of the respective layer and / or the material properties in terms of optimization parameters (eg to be damped Frequencies or temperature resistance, chemical resistance) be adjusted. In addition, the damping element on a top and / or bottom by a metallic sheet be covered to the stabilizing properties of the damping element continue to increase. Since the damping element off inexpensive to produce material and no consuming Costs incurred, the invention is in any case extremely inexpensive and effective.

One another possibility of the design of the damping element consists in that the damping element at least two metallic Has sheets between which the vibration-damping Layer is arranged. This damping element is also preferred disc-shaped and acts as a base between the flange of the high-pressure fuel pump and the mounting structure the internal combustion engine. While in the first described Embodiment of the damping element, the viscoelastic Properties were increased are in the second embodiment through the use of two metallic sheets the stabilizing Features of the attachment increased. manufacturing technology Here is the viscoelastic layer between the two sheets laminated. Here is a bending stress in the middle lying viscoelastic sandwich layer dynamically strong on shear claimed and thus a high proportion of vibration energy Material damping dissipated. Similar effects act at a normal load, especially under pressure on the sheet. In this case, the viscoelastic layer is compressed and deviates in sheet metal direction, which in turn leads to dissipation due to material deformation in the viscoelastic layer leads. This will produce a sound energy in the transmission path reduced from flange to mounting structure. The dissipation of body sound energy leads in any case to a damping of vibration modes the high-pressure fuel pump and to a reduction of all structure-borne noise, which are transmitted through the viscoelastic layer.

Furthermore it is suggested that the vibration damping layer profiling or micro profiling on at least one side having. This means that at least one side of the vibration-damping Layer that consists of viscoelastic material and directly on the Flange or rests on the mounting structure, has knobs. Thereby the vibration-damping effect is further increased.

Possible is also that the vibration-damping layer transport safety and / or having a mounting aid. This is the vibration-damping Layer after the production of the high-pressure fuel pump and after the simple pressing on the flange, for example, by the circumference the vibration-damping layer arranged retaining clips already in a planned installation position, so for example. Relative centered on the flange, held. Constructive changes at the high pressure pump are not required. This facilitates the assembly of the high-pressure fuel pump, since during assembly the Mounting screws only used and with the mounting structure must be screwed. It is also possible that after production instead of the retaining clips mounting pins in the Holes used to attach the high pressure fuel pump are.

Brief description of the drawings

following Be with reference to figures advantageous embodiments the invention explained in more detail. Show it:

1 a schematic diagram of an internal combustion engine with a high-pressure fuel pump;

2 a perspective view of the high pressure fuel pump 1 ;

3 a first embodiment of a vibration damping layer according to the invention;

4 A second embodiment of the vibration damping layer according to the invention;

5 a third embodiment of the vibration damping layer according to the invention;

6 a schematic representation of a first way of securing the high-pressure fuel pump 1 or 2 ;

7 a schematic representation of a second way of attaching the high-pressure fuel pump 1 or 2 ;

8th a perspective view of a flange of the high-pressure fuel pump 2 with a first possible transport lock / mounting aid for the vibration-damping layer; and

9 a perspective view of the flange of the high-pressure fuel pump 2 with a second possible transport lock / mounting aid for the vibration-damping layer.

embodiments the invention

An internal combustion engine carries in 1 Overall, the reference number 10 , It includes a fuel tank 12 from which a prefeed pump 14 Fuel in a low pressure line 16 promotes. The pressure in the low pressure line 16 is by a pressure control or pressure control valve 18 set.

The low pressure line 16 leads to a high pressure fuel pump 20 whose construction is in 2 will be described in more detail. The high pressure fuel pump 20 is mechanically from the internal combustion engine 10 driven. It compresses the fuel to a very high pressure and delivers it to a high-pressure fuel accumulator 22 which is also referred to as a "rail". There are several injectors on these 24 connected to the fuel under high pressure in them directly associated combustion chambers 26 inject. The operation of the internal combustion engine 10 is controlled by a control device 28 controlled and regulated.

In 2 is the in 1 schematically indicated high pressure fuel pump 20 shown in perspective. The high pressure fuel pump 20 is designed as a radial piston pump and has a pump housing 32 whose outer surface approximates the shape of a hexagon. On the pump housing 32 is a pump cover 34 arranged. In an in 2 Rear-facing area is a quantity control valve 36 arranged. The pump housing 32 is via a flange 38 at the in 1 illustrated internal combustion engine 10 via mounting screws (in 2 not shown) on a designated mounting structure (in 2 not shown) of the internal combustion engine 10 attached. This is indicated by the flange 38 drilling 39 for installing the mounting screws. From the pump housing 32 protrudes a pump piston 40 for the mechanical drive of the high-pressure fuel pump 20 out, of a piston spring 42 is surrounded.

On the outside of the pump housing 32 Different connections for fuel lines are arranged. The in 2 middle connection is through a low-pressure connection 44 formed by the in 1 shown prefeed pump 14 is fed to a low pressure area of the high pressure fuel pump 20 leads. The in 2 port shown on the left is through a high-pressure connector 46 formed, which is a high pressure area of the high pressure fuel pump 20 is assigned and the fuel high-pressure accumulator 22 ( 1 ) feeds. The in 2 Right hand port shown is through a neck 48 formed, the leakage fuel from the high-pressure fuel pump 20 Fuel in the fuel tank 12 ( 1 ) feeds.

The high pressure fuel pump 20 is designed as a plug-in pump, which in a corresponding opening in the motor housing (not shown) of the internal combustion engine 10 is plugged in. In operation, then the radially seated on a cam or balance shaft piston 40 put in a float. The piston stroke compresses the fuel in a delivery chamber (not visible) and to the high-pressure connection port 46 promoted. For this reason, the pump sits relatively stiff in and on the motor housing ("mounting structure").

In the high pressure fuel pump 20 it comes due to the cyclical fuel delivery and the quantity control by the quantity control valve 36 to generate body and fluid sound throughout the audible frequency range. This is essentially due to pulsations (fluid sound) in the low-pressure range and through the high-pressure fuel pump 20 generated structure-borne noise generated. The flange 38 forms - without countermeasures - with the mounting structure of the internal combustion engine, a transition region, via the structure-borne noise in the form of vibrations from the internal combustion engine 10 on the high-pressure fuel pump 20 and body and fluid sounds in the form of vibrations from the high pressure fuel pump 20 to the internal combustion engine 10 is transmitted. The vibrations are partially over the pump housing 32 and over the low pressure line 16 on all body parts and for example one Tank attachment unit (not shown) transmitted, which leads there to an undesirable, disturbing sound radiation. In addition, due to vibrations resulting from the vibrations, different components, in particular the flange 38 the high pressure fuel pump 20 loaded.

In the internal combustion engine shown here is therefore a damping element 50 ( 3 to 7 ) with a vibration-damping layer 54 to reduce the transmission of sound between the flange 38 and the growing structure 56 (only in the 6 and 7 shown) of the internal combustion engine 10 used. The damping element 50 includes at least one metallic sheet 52 and at least one respective viscoelastic layer applied thereto 54 (so-called "sandwich" or "compound" sheets), so that a disc-shaped damping element 50 results. In addition, the damping element 50 Holes for mounting screws (only in the 6 and 7 shown).

3 shows a structure of a first embodiment of the disc-shaped damping element 50 , The damping element 50 has two metal sheets arranged parallel to one another 52 on, between which the vibration-damping layer 54 is arranged. The vibration damping layer is made of a viscoelastic material and laminated between the two sheets. The sheets 52 may be made in a non-illustrated embodiment of different thickness and / or of a different material. The present embodiment is particularly stiff. Of course, the damping element and more than two sheets 52 and therefore more than a viscoelastic layer 54 exhibit.

4 shows a structure of the disc-shaped damping element 50 in a second embodiment. To 3 identical or functionally equivalent components are identified here and below with the same reference numerals.

In 4 has the damping element 50 a single metallic sheet 52 on both sides with a vibration-damping layer 54 is coated from viscoelastic material, for example by lamination. The thickness of the viscoelastic material 54 can be different. Of course, here too, the damping element 50 more than a sheet 52 and thus more than two vibration-damping layers 54 exhibit.

5 shows a structure of the disc-shaped damping element 50 in a third embodiment. To 3 and 4 identical or functionally equivalent components are identified by the same reference numerals.

In the embodiment of 5 are the embodiments of 3 and 4 combined together. The damping element 50 has two metal sheets arranged parallel to one another 52 on, between which a first vibration-damping layer 54 coated from a viscoelastic material, preferably laminated. Additionally is in 5 the upper side of the damping element 50 from the outside with a vibration-damping layer 54 coated from viscoelastic material, which is also preferably laminated. Again, the thickness of the sheets 52 and / or the vibration damping layers 54 be different. Of course, the damping element of course more than two sheets 52 and thus more than two vibration-damping layers 54 exhibit.

The exemplary embodiments show that the arrangement of the individual layers (sheet metal 52 and vibration-damping layer 54 ) of the damping element 50 may be very specific to the specific application.

6 shows a schematic representation of a first possibility of attachment of the high-pressure fuel pump 20 out 1 or 2 using the first and in 3 shown embodiment of a damping element 50 , The high pressure fuel pump 20 points in 6 on its underside the flange 38 on. Between the flange 38 and the growing structure 56 the internal combustion engine 10 is the disk-shaped damping element 50 arranged. The flange 38 includes holes 39 (in 6 is only one hole 39 visible), in the mounting screws 58 are used. The mounting screws 58 penetrate the disc-shaped damping element 50 , which also has holes (without reference numerals) for it. Through a thread 60 The mounting screws will be the entire construction, consisting of high pressure fuel pump 20 with flange 38 and the disc-shaped damping element 50 at the cultivation structure 56 attached.

The effect of the device described is that through the use of the disc-shaped damping element 50 Due to the high material damping in the viscoelastic layer a reduction of the vibration properties and the structure-borne sound emission is realized without the rigid connection of the high-pressure fuel pump 20 at the cultivation structure 56 too flexible. It is immaterial whether the vibrations from the internal combustion engine 10 or from the high pressure fuel pump 20 originate. The required rigid and rigid attachment of the high-pressure fuel pump 20 on the cultivation structure 56 is essentially retained and continues to meet the requirements for acoustics, function and strength, resulting from a high pressure fuel pump design.

7 shows a schematic representation of an alternative to the in 6 illustrated attachment of the high-pressure fuel pump 20 , To 6 identical or functionally equivalent components are denoted by the same reference numerals and will not be explained again. The only difference in 7 to 6 is that under a screw head 62 the mounting screw 58 also a disc-shaped damping element 50 is used.

The embodiment of 7 has an improved sound-absorbing effect, as the sound transmission through the mounting screws 58 in addition to the effects described 6 prevented or at least greatly attenuated.

The 8th and 9 show ways to the damping element 50 to bring after production already in an intended installation position, so that when mounting only the mounting screws 58 must be used and bolted to the mounting structure. So will in 8th the damping element 50 by means of four on the circumference of the damping element 50 arranged retaining clips 64 on the flange 38 held, so that the holes 39 of the flange 38 with the corresponding holes in the damping element 50 cover. After assembly, the retaining clips can remain on the device. Holding the damping element 50 on the flange 38 the high pressure fuel pump 20 can either by means of a non-positive or a positive connection of the retaining clips 64 done with the flange.

9 shows an alternative way to position the damping element 50 , at the mounting pins 66 into the holes 39 and the holes in the damping element 50 are used, which the damping element 50 hold and opposite the flange 38 Center. The mounting pins 66 then, before mounting, only need to go through the final mounting screws 58 be replaced. The mounting pins 66 are designed to be smooth on the circumference, but they can also have a thread or a corrugation or a friction layer, by which the damping element is secured to the flange.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102005033634 A1 [0002]

Claims (10)

High pressure fuel pump ( 20 ) for a fuel injection system of an internal combustion engine ( 10 ) with a pump housing ( 32 ), which has a flange ( 38 ) for attachment to the internal combustion engine ( 10 ), characterized in that between the flange ( 38 ) and the internal combustion engine ( 10 ) a vibration-damping layer ( 50 ) is arranged. High pressure fuel pump ( 20 ) according to claim 1, characterized in that the flange ( 38 ) via mounting screws ( 58 ) on the internal combustion engine ( 10 ) and between the screw heads ( 62 ) of the mounting screws ( 58 ) and the flange ( 38 ) a vibration-damping layer ( 50 ) is arranged. High pressure fuel pump ( 20 ) according to claim 1 or 2, characterized in that the vibration-damping layer ( 50 ) a viscoelastic material ( 54 ). High pressure fuel pump ( 20 ) according to one of the preceding claims, characterized in that it comprises a damping element which comprises at least one metallic sheet ( 52 ), and that at least on one side of the sheet, the vibration-damping layer is arranged. High pressure fuel pump ( 20 ) according to claim 4, characterized in that the damping element comprises at least two metallic sheets, between which the vibration-damping layer is arranged. High pressure fuel pump ( 20 ) according to one of claims 4 or 5, characterized in that the damping element comprises at least one metallic sheet, which has a vibration-damping layer on both sides. High pressure fuel pump ( 20 ) according to one of the preceding claims, characterized in that the vibration-damping layer ( 50 ) has a profiling or micro-profiling on at least one side. High pressure fuel pump ( 20 ) according to one of the preceding claims, characterized in that the vibration-damping layer ( 50 ) a transport safety device ( 64 ) and / or an assembly aid ( 64 . 66 ) having. High pressure fuel pump ( 20 ) according to claim 8, characterized in that the transport lock or assembly aid at least one clip ( 64 ) comprising the layer ( 50 ) on the flange ( 38 ) secures. High pressure fuel pump ( 20 ) according to one of claims 8 or 9, characterized in that the transport lock or assembly aid at least one mounting pin ( 66 ), which in a mounting opening ( 39 ) of the flange ( 38 ) and the layer ( 50 ) opposite the flange ( 38 ).