CN108779766B

CN108779766B - High pressure pump with fluid damper

Info

Publication number: CN108779766B
Application number: CN201780017487.6A
Authority: CN
Inventors: D·凯尔巴赫
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2016-03-14
Filing date: 2017-01-26
Publication date: 2020-07-17
Anticipated expiration: 2037-01-26
Also published as: EP3430261A1; KR20180121982A; WO2017157554A1; DE102016204128A1; CN108779766A; EP3430261B1

Abstract

The invention relates to a high-pressure pump having a pump housing (2) on which a pump cartridge head (4) having a pump cartridge (3) is arranged, wherein a pump tappet (26) is arranged in a pump cartridge guide (27) of the pump cartridge (3), which interacts with a pump working chamber (36) and a drive mechanism chamber (8) arranged in the pump housing (2), wherein the pump working chamber (36) is fluidically connected to the drive mechanism chamber (8) via an electromagnetically actuable suction valve (6), and wherein the high-pressure pump has a fluid damper. According to the invention, a high-pressure pump is provided which is improved with regard to pressure fluctuations or pressure pulses of the fluid to be conveyed. This is achieved in the following way: the fluid damper is designed as at least one diaphragm (38a, 38b) which is inserted into a damper chamber (19) which is provided in the pump housing (2).

Description

High pressure pump with fluid damper

Technical Field

The invention relates to a high-pressure pump having a pump housing on which a pump cartridge head having a pump cartridge is arranged, wherein a pump plunger is arranged in a pump cartridge guide of the pump cartridge, which pump plunger interacts with a pump working chamber that can be filled with fluid and a drive mechanism chamber that is arranged in the pump housing and can be filled with fluid, and wherein the pump working chamber can be fluidically connected to the drive mechanism chamber via an electromagnetically actuable suction valve, and wherein the fluid guide of the high-pressure pump has a fluid damper.

Background

Such a high-pressure pump is known from DE 102013207393 Al. The high-pressure pump is part of a fuel injection system of an internal combustion engine. The high-pressure pump has a pump housing on which a pump cartridge head having a pump cartridge is arranged, wherein a pump tappet for delivering fuel is arranged in a pump cartridge guide of the pump cartridge. For this purpose, a pump working chamber is arranged adjacent to the pump barrel guide, to which fuel can be supplied by the drive mechanism chamber of the high-pressure pump via an electromagnetically actuable suction valve. Furthermore, the high-pressure pump has a fluid damper, which is arranged outside the high-pressure pump on the pump housing in the inflow region for the fuel. The fluid damper is inserted into a housing cap which is fastened to the pump housing on the outside thereof.

Disclosure of Invention

The object of the present invention is to provide a high-pressure pump which is improved with regard to damping of pressure fluctuations or pressure pulses of the fluid to be delivered.

This object is achieved in the following manner: the fluid damper is inserted into a damper chamber provided in the pump housing. This configuration is based first of all on the following recognition: pressure fluctuations or pressure pulses in the high pressure pump area may cause cavitation and/or tearing of the lubrication film between the components of the high pressure pump. In addition, vibrations can occur in the peripheral units that interact with the high-pressure pump, in particular in the region of the fluid lines and the components attached thereto, which vibrations cause noise. In the worst case, the lines or the components contained therein, such as filters, can be damaged or destroyed. In the case of the previously known and in practical use fluid dampers are added to the inlet line to the high-pressure pump or to the outside of the high-pressure pump, which constitutes a high construction outlay and is also susceptible to disturbances. Furthermore, the position requirement of the high-pressure pump is increased, for example, by the addition of a fluid damper externally to the high-pressure pump. The aforementioned disadvantages are avoided by the incorporation of the fluid damper into the damper chamber integrated into the pump housing according to the invention.

In a development of the invention, the fluid damper is a diaphragm. The diaphragm is of annular or cylindrical design and has two opposite annular end faces which enclose an inner diaphragm chamber and are movable relative to one another. Such a diaphragm is known in principle and can be made, for example, of a metallic material. That is, the diaphragm chamber is formed between two opposite end faces and is filled with a gas, for example.

In a further embodiment of the invention, the diaphragm is acted upon on both sides by the fluid pressure prevailing in the damper chamber. This makes it possible to achieve ideal operation of the membrane by: the pressure variation process on both sides of the diaphragm is synchronized. In other words, the pressure change process of the medium on both sides of the diaphragm and the diaphragm surface of the diaphragm are the same and p1(t) ═ p2(t) exists. The filling according to the invention with the membrane and the supply of fluid fuel via the inflow channel below the membrane cause the end face to be pressure-loaded in the longitudinal direction or parallel to the end face. Thereby positively affecting the function and durability of the membrane.

In a further embodiment of the invention, the inflow connection opens directly into the drive chamber and into a damper chamber directly connected thereto or via a supply channel. This configuration allows the installation position of the fluid damper or diaphragm to be arranged as close as possible to the source of the pressure fluctuations or pressure pulses.

In a further embodiment of the invention, at least two diaphragms are arranged in the damper chamber. This configuration can be easily implemented by means of a damper chamber provided in the pump housing, wherein the arrangement with respect to the inflow connection is oriented as implemented such that the diaphragm is arranged along the pulse propagation direction and not transverse thereto as has been the case hitherto. Thereby reducing the load on the diaphragm. The service life of the diaphragm mounted in this way is thereby increased, and the service life of the high-pressure pump, or the maintenance intervals of the high-pressure pump, is thereby also increased or lengthened.

In a further embodiment of the invention, the damper chamber is arranged between the drive mechanism chamber and the tappet chamber attachment or tappet chamber below the pump cylinder head. Damping is thereby effected directly at the two main pulse sources caused by the high-pressure pump. In addition, the damper chamber is directly adjacent to the inlet and return connections. This has a positive effect on the damping of the inflow and the return of the fluid with the pulses introduced therein.

In a further embodiment of the invention, the at least one diaphragm can be inserted into a diaphragm holder, which can be inserted into the damper chamber. This is a preferred form of construction which enables a smooth fit of the at least one diaphragm in the damper chamber. In this case, it is possible to install differently designed diaphragms for different applications in the damper chambers, which are always designed identically, on the high-pressure pump.

In a further embodiment of the invention, the damper chamber has a mounting opening which can be covered by a chamber cover. The mounting opening is arranged on the high-pressure pump such that the damper chamber is accessible even when the high-pressure pump is completely equipped with the attachment. The damper chamber is thus accessible without disassembling the high-pressure pump. The chamber cover can be screwed, for example, with the pump housing with the sealing ring installed.

In a further advantageous embodiment of the invention, the drive chamber is connected to the damper chamber and both of them are connected via a connecting channel to the tappet chamber below the pump cylinder head. This configuration can be advantageously implemented in terms of design and manufacturing technology and furthermore offers the following advantages: the direct connection of the zero components to one another achieves advantages with regard to damping of pressure fluctuations or pressure pulses of the fluid to be conveyed.

In a further embodiment of the invention, the high-pressure pump, which is designed as a high-pressure fuel pump, is part of a fuel injection system of the internal combustion engine, wherein the fuel injection system is designed, for example, as a common rail fuel injection system and is designed for injecting fuel, for example, diesel fuel or gasoline, into a combustion chamber of the internal combustion engine.

Drawings

Further advantageous embodiments of the invention can be taken from the description of the figures, in which the embodiments of the invention shown in the figures are described in detail.

The figures show:

figure 1 is a perspective general view of a high pressure pump constructed in accordance with the present invention,

figure 2 a cross-section of the high pressure pump of figure 1,

figure 3 a longitudinal cross-section of a high pressure pump constructed in accordance with the present invention of figure 1,

fig. 4 is a perspective view of the high pressure pump similar to fig. 1, with an exploded view of the components of the fluid damping device,

figure 5 a cross-sectional view of a pump housing of the high pressure pump of figure 1,

FIG. 6a shows a representation of the pressure loading of the diaphragm used hitherto in practice, and

fig. 6b shows the pressure loading of the membrane by means of the embodiment according to the invention.

Detailed Description

Fig. 1 shows a perspective view of a high-pressure pump, which is designed as a high-pressure fuel pump 1 of a fuel injection system. The fuel injection system is installed on the internal combustion engine, and the high-pressure fuel pump delivers the fuel supplied by the low-pressure fuel system at a delivery pressure of, for example, up to 3000bar to a high-pressure accumulator connected to the high-pressure fuel pump 1 via a high-pressure line, from which the fuel injectors extract the fuel stored there for controlled injection into the corresponding combustion chambers of the internal combustion engine. The fuel is, for example, diesel fuel, and the internal combustion engine is a self-igniting internal combustion engine.

The high-pressure fuel pump has a pump housing 2, on which a pump cartridge head 4 with a pump cartridge 3 (see also fig. 2) is fitted. The pump cartridge head 4 has a high-pressure connection 5 for connection to a high-pressure line. Furthermore, an electrically actuable suction valve 6, which is described in more detail below with reference to fig. 2, is inserted into the pump cylinder head 4. The suction valve 6 has a connection plug 7 for electrical connection to an electronic control device.

A drive chamber 8, which can be seen in fig. 2, is provided in the pump housing 2, in which drive chamber 8a camshaft 10 with a double cam 9 is rotatably mounted. In order to insert the camshaft 10 into the pump housing 2, the drive chamber 8 is closed off from the surroundings by a pump housing cover 11, through which cover 11 a drive cone 12 of the camshaft 10 projects. A drive gear, which is set in a rotationally fixed manner, for example, by a drive shaft of the internal combustion engine during operation of the internal combustion engine, is attached to the drive cone 12, for example, in a rotationally fixed manner. The pump housing 2 furthermore has an inlet connection 13 and a return connection 14. The inlet connection 13 is connected to a low-pressure fuel system, for example, via a pressure-resistant inlet hose, while the return connection 14 is connected to a fuel tank, for example, via a return hose. In particular, the chamber cover 15 is screwed together with the sealing ring 16 (fig. 2) by means of three screws 17, in particular on the side of the inlet connection 13 and the return connection 14. The chamber cover 15 closes a mounting opening 18 of a damper chamber 19, which is also explained below.

Fig. 2 shows a longitudinal section through the high-pressure fuel pump 1 of fig. 1, wherein it can be seen from this illustration that the pump barrel 3 of the pump barrel head 4 projects into the tappet chamber 20 in the pump housing 2. In the cylindrically formed tappet chamber 20, a roller tappet 21 is inserted, which rolls with a working roller 22 on a double cam 9 of the camshaft 10, which double cam is arranged in the drive mechanism chamber 8, during a rotational movement of the camshaft 10, so that the roller tappet 21 moves in a translational manner up and down in the tappet chamber 20. In order to keep the roller tappet 21 and the working roller 22 in constant contact with the double cam 9 of the camshaft 10, a tappet spring 23 is arranged in the tappet chamber 20, which tappet spring is clamped between the pump cylinder head 4 and a retaining disk 24, which is arranged in the roller tappet 21. The retaining disk 24 rests on an inner annular bearing surface 25 of the roller tappet 21 and simultaneously retains a pump tappet 26, which is movable in translation in a pump cylinder guide 27 provided in the pump cylinder 3, with a pump tappet foot 28 against a working roller retainer 29 of the roller tappet 21.

The inflow connection 13 (see also fig. 3) is connected to the drive chamber 8 via an inflow channel 30 (see also fig. 5). The drive mechanism chamber 8 itself is connected with the damper chamber 19 and the drive mechanism chamber 8 and the damper chamber 19 are connected with the push rod chamber 20 below the pump barrel head 4 via the connecting

channels

31a, 31 b. The connecting channel 31a has a continuation 32 (fig. 2), which continuation 32 opens into a contact surface 33 of the pump housing 2 for contacting the pump cartridge head 4. The extension 32 extends in a supply channel 34, which supply channel 34 is provided in the pump cylinder head 4 and is connected to the solenoid-actuated suction valve 6. The solenoid-operated suction valve 6 has an inlet valve 35, which is operated by the suction valve 6 and which, in the open state, connects a supply channel 34 to a pump working chamber 36, which is arranged in the pump cylinder head 4 in the extension of the pump cylinder guide 27 above the pump tappet 26. Thus, when the inlet valve 35 is open, fuel supplied via the inflow connection 13 is introduced into the pump working chamber 36 during the downward movement of the pump plunger 26, whereas when the pump plunger 26 is subsequently moved upward, fuel is displaced back into the fuel low-pressure system on the same line when the inlet valve 35 is open. If the inlet valve 35 is closed by the switching process of the solenoid-actuated suction valve 6, pressure builds up in the pump working chamber 36 and the fuel located in the pump working chamber 36 is conveyed via the non-return valve 37 into the high-pressure connection 5. Fig. 5 also shows a return channel 43, which is connected to the return connection 14 and which, for example, leads the fuel which is conducted through for cooling and lubrication purposes back into the low-pressure system or the fuel tank via bearings which are arranged in the pump housing 2 and the pump housing cover 11 and which are used to support the camshaft 10.

Due to the aforementioned conventional function of the high-pressure fuel pump 1 and also due to the low-pressure fuel system, pressure pulses to be damped are formed in the high-pressure fuel pump 1. For this purpose, a fluid damping device is provided in the damper chamber 19, which is explained later with reference to fig. 2, 3 and 4. In the exemplary embodiment shown, the fluid damping device has two

diaphragms

38a, 38b, which, with the diaphragm spring 39, which is made of spring steel, for example, inserted into a diaphragm holder 40, which is preferably designed as a stamped and bent part. The diaphragm holder 40 preassembled in this way is introduced into the damper chamber 19 via the assembly opening 18 according to fig. 4, and the chamber cover 15 is then screwed to the pump housing 2 by means of the screws 17, with the sealing ring 16 installed. The

diaphragms

38a, 38b are of annular or cylindrical design and have an internal diaphragm chamber 41 which is filled with a medium, for example a compressible gas. If a force acts on the two opposing annular end faces 42 of the two

diaphragms

38a, 38b, respectively, the two end faces 42 are deformed inwardly towards the diaphragm chamber 41. This effect serves to dampen the pressure fluctuations or pressure pulses that prevail in the high-pressure fuel pump 1. The aforementioned charging by the

diaphragms

38a, 38b and the fuel are supplied via the inflow channel 30 below the

diaphragms

38a, 38b, which are pressurized in the longitudinal direction (parallel to the end face 42) as shown in fig. 6b and not in the transverse direction (on the front face of the end face 42) as is reflected in fig. 6a in conventional diaphragms.

Claims

1. A high-pressure pump having a pump housing (2) on which a pump cartridge head (4) having a pump cartridge (3) is arranged, wherein a pump plunger (26) is arranged in a pump cartridge guide (27) of the pump cartridge (3) and interacts with a pump working chamber (36), wherein the pump working chamber (36) can be filled with fluid via an electromagnetically actuable suction valve (6), and wherein the high-pressure pump has a fluid damper which is inserted into a damper chamber (19) which is provided in the pump housing (2), characterized in that a drive mechanism chamber (8) is arranged in the pump housing (2), the pump working chamber (36) can be brought into fluid communication with the drive mechanism chamber (8) via the electromagnetically actuable suction valve (6), the damper chamber (19) is connected to the drive mechanism chamber (8) and the drive mechanism chamber (8) is arranged in the pump housing (2) ) Is used for supplying the medium to be delivered by the high-pressure pump into the drive chamber (8).

2. The high-pressure pump as set forth in claim 1,

characterized in that the fluid damper is at least one diaphragm (38a, 38 b).

3. The high-pressure pump as set forth in claim 2,

characterized in that the membrane (38a, 38b) has an inner membrane chamber (41) filled with a medium.

4. The high-pressure pump according to claim 2 or 3,

characterized in that the diaphragms (38a, 38b) are pressure-loaded on both sides by the fluid pressure prevailing in the damper chamber (19).

5. The high-pressure pump according to claim 4,

characterized in that the diaphragms (38a, 38b) are pressure-loaded parallel to opposite end faces (42) of the diaphragms.

6. The high-pressure pump according to any one of claims 2, 3 and 5,

characterized in that at least two diaphragms (38a, 38b) are inserted parallel to each other into the damper chamber (19).

7. The high-pressure pump as claimed in one of claims 2, 3 and 5, characterized in that the diaphragms (38a, 38b) are inserted into a diaphragm holder (40) which can be inserted into the damper chamber (19).

8. The high-pressure pump according to any one of claims 1, 2, 3 and 5,

characterized in that the damper chamber (19) has a fitting opening (18) which can be covered by a chamber cover (15).

9. The high-pressure pump according to any one of claims 1, 2, 3 and 5, characterized in that the drive mechanism chamber (8) is connected with the damper chamber (19), and the drive mechanism chamber and the damper chamber are connected with a push rod chamber (20) below the pump barrel head (4) via connecting channels (31a, 31 b).

10. A fuel injection system having a high-pressure pump configured as a high-pressure fuel pump (1), which high-pressure pump is a high-pressure pump according to one of the preceding claims.