KR20180121982A - High pressure pump with fluid damper - Google Patents

Abstract

The present invention relates to a high-pressure pump including a pump housing (2) in which a pump cylinder head (4) having a pump cylinder (3) is disposed. In the pump cylinder guide (27) of the pump cylinder (3) A pump tappet 26 is disposed which interacts with the pump operation chamber 36 and the drive unit chamber 8 disposed in the pump housing 2 and the pump operation chamber 36 is connected to the electromagnetic operated suction valve 6 To the drive unit chamber (8), the high pressure pump comprising a fluid damper. According to the present invention, an improved high-pressure pump is provided in connection with damping of pressure fluctuations or pressure pulsations of a fluid to be transferred. This is achieved by forming the fluid damper into one or more membranes 38a, 38b which are inserted into the damper chamber 19, which is recessed in the pump housing 2. [

Description

High pressure pump with fluid damper

The present invention relates to a high-pressure pump including a pump housing in which a pump cylinder head with a pump cylinder is disposed, wherein the pump cylinder guide of the pump cylinder is provided with a pump operating chamber, A pump tappet is disposed that interacts with a drive unit chamber that can be filled with fluid and the pump operation chamber can be fluidly connected to the drive unit chamber through an electromagnetically actuated suction valve and a fluid guide guide includes a fluid damper.

A high pressure pump of this type is known from DE 10 2013 207 393 A1. The high-pressure pump is part of the fuel injection system of the internal combustion engine. The high-pressure pump includes a pump housing in which a pump cylinder head including a pump cylinder is disposed, and a pump tappet for transferring fuel is disposed in a pump cylinder guide of the pump cylinder. To this end, a pump operation chamber is arranged adjacent to the pump cylinder guide, through which the fuel can be supplied from the drive unit chamber of the high-pressure pump via an electromagnetically operated suction valve. The high pressure pump also includes a fluid damper, which is disposed on the pump housing in the region of the fuel supply outside the high pressure pump. The fluid damper is housed in a housing casing fixed on the pump housing from the outside.

It is an object of the present invention to provide an improved high-pressure pump in connection with damping of pressure fluctuations or pressure pulsations of a fluid to be transferred.

The above problem is solved by inserting the fluid damper into a recessed damper chamber formed in the pump housing. This embodiment is based on the fact that pressure fluctuations or pressure pulsations in the region of the high pressure pump may first cause cavitation and / or lubricant rupture between the components of the high pressure pump. Also, vibrations that cause noise may occur in the area of the peripherals that interact with the high pressure pump, especially the fluid lines on which the components are mounted. In the worst case, lines, or components mounted in the lines, such as filters, can be damaged or broken. It is highly structurally complicated to install the fluid damper in the supply line to the high pressure pump or on the high pressure pump on the outside as conventionally known and practiced, and the fluid damper can fail well. Further, for example, by providing a fluid damper on the outside of the high-pressure pump, the space demand of the high-pressure pump is increased. These disadvantages are avoided by embedding a fluid damper in accordance with the present invention in a damper chamber incorporated within the pump housing.

In an improvement of the present invention, the fluid damper is a membrane. The membrane is formed in an annular or cylindrical shape and includes two annular end faces that are opposed to each other and that can move toward each other surrounding the inner membrane chamber. The membrane is basically known and can be made of, for example, a metal material. In other words, the membrane chamber is formed between two end faces opposing each other and is filled, for example, with a gas.

In an improvement of the invention, the membrane is pressurized by fluid pressure predominantly present in the damper chamber on both sides. Thus, the pressure profiles on both sides of the membrane are synchronized to enable ideal operation of the membrane. In other words, the pressure profiles of the media on both sides of the membrane or membrane surfaces are the same and p ₁ (t) = p ₂ (t) is applied. By embedding the membrane in accordance with the invention and supplying fluid, i. E. Fuel, through the supply channel at the bottom of the membrane, the end faces are pressed in the longitudinal direction or parallel to the end faces. Therefore, the function of the membrane and its durability are also positively influenced.

In yet another embodiment of the present invention, the supply port is directly or through the supply channel into the drive unit chamber and into the damper chamber directly connected to the drive unit chamber. Through this embodiment, the attachment position of the fluid damper or membrane is assigned as close as possible to the source of pressure fluctuations or pressure pulsations.

In another embodiment of the present invention, two or more membranes are disposed in the damper chamber. This embodiment is easily realized through a damper chamber formed in the pump housing and the arrangement in relation to the supply port is such that the membrane is not arranged transversely (as was described above) . Thus reducing the load acting on the membrane. As a result, the useful life of the membrane thus mounted increases, thereby increasing or extending the useful life of the high-pressure pump and the maintenance period of the high-pressure pump, respectively.

In another embodiment of the present invention, the damper chamber comprises: a tappet chamber below the pump cylinder head, and a drive unit chamber and a tappet chamber connection; Respectively. Thus, direct damping is performed at the two main pulsation sources triggered by the high-pressure pump. Further, the damper chamber is disposed immediately next to the supply port and the return port. This positively affects the fluid supply portion and the recovery portion with respect to the damping of the pulsation introduced into the supply portion and the recovery portion of the fluid.

In another embodiment of the present invention, one or more membranes may be inserted into a membrane holder, which may be embedded within the damper chamber. This is a preferred embodiment to enable smooth assembly of one or more membranes in the damper chamber. It is also possible in this case to mount membranes which are differently formed for various applications in a damper chamber which is always formed identically on the high-pressure pump.

In yet another embodiment of the present invention, the damper chamber includes an assembly opening that can be covered by the chamber cover. The assembly opening is disposed on the high-pressure pump so that the high-pressure pump can reach the assembly opening even when the add-on part is fully mounted. Therefore, it is possible to reach the damper chamber without disassembling the high-pressure pump. The chamber cover can be fixed with the pump housing and the screw, for example, with the seal ring fitted.

In another preferred embodiment of the present invention, the drive unit chamber is connected to the damper chamber, which is connected to the tappet chamber below the pump cylinder head via the connection channels. This embodiment may be advantageously implemented in terms of construction and manufacturing techniques and further provides advantages associated with damping pressure fluctuations or pressure pulsations of the fluid to be transferred through direct interconnection of components.

In another embodiment of the present invention, a high pressure pump formed as a fuel high pressure pump is part of a fuel injection system of an internal combustion engine, and the fuel injection system is configured as a common rail fuel injection system, for example, to inject fuel into the combustion chamber of an internal combustion engine, And is formed to inject gasoline.

Further preferred embodiments of the present invention are derived from the following description of the drawings, in which one embodiment of the invention shown in the drawings is described in more detail.

1 is an overall perspective view of a high-pressure pump formed in accordance with the present invention;
Fig. 2 is a cross-sectional view showing the high-pressure pump according to Fig. 1 cut away. Fig.
3 is a longitudinal sectional view of a high-pressure pump according to the present invention formed by cutting a high-pressure pump according to the present invention.
4 is a perspective view showing a high-pressure pump similar to that of Fig. 1 with an exploded view of the components of the fluid damping device.
5 is a cross-sectional view of the pump housing of the high-pressure pump according to FIG.
6A is a view for explaining a conventional practical membrane pressurization.
6B is a view for explaining pressurization of a membrane, which is realized through an embodiment according to the present invention.

1 is a perspective view of a high-pressure pump formed as a fuel high-pressure pump 1 of a fuel injection system. The fuel injection system is mounted on the internal combustion engine, and the fuel high pressure pump transfers the fuel supplied by the fuel low pressure system to the high pressure accumulator connected to the fuel high pressure pump 1 through the high pressure line, for example, at a conveying pressure of 3,000 bar or less , The fuel stored in this high pressure accumulator is discharged from the high pressure accumulator by fuel injectors for controlled injection into the assigned combustion chambers of the internal combustion engine. The fuel is, for example, diesel oil, and the internal combustion engine is a self-priming internal combustion engine.

The fuel high-pressure pump includes a pump housing 2 on which a pump cylinder head 4 including a pump cylinder 3 (see also Fig. 2) is mounted. The pump cylinder head 4 includes a high-pressure port 5 for connection with a high-pressure line. In addition, an electrically operated suction valve 6 is built in the pump cylinder head 4, and this suction valve is dealt with again with reference to Fig. 2 below. The intake valve 6 includes a connector 7 for electrical connection with an electronic control unit.

The pump housing 2 is provided with a drive unit chamber 8, which can be seen in FIG. 2, in which a camshaft 10 including a double cam 9 is rotatable Respectively. The drive unit chamber 8 is closed with respect to the surrounding environment by the pump housing cover 11 and the drive taper portion 12 of the camshaft 10 is closed for the interior of the camshaft 10 in the pump housing 2. [ a drive taper is projected through the pump housing cover. For example, a drive gear wheel is mounted on the drive tapered portion 12 in a rotationally fixed manner, and the drive gear wheel rotates during operation of the internal combustion engine by, for example, the drive shaft of the internal combustion engine. The pump housing 2 also includes a supply port 13 and a return port 14. The supply port 13 is connected to the fuel low pressure system via, for example, a pressure-resistant supply hose, while the return port 14 is connected to, for example, a fuel tank via a return hose. The chamber cover 15 is screwed with, for example, three screws 17, with the seal ring 16 (Fig. 2) being fitted on the side surface, in particular, next to the supply port 13 and the return port 14. [ The chamber cover 15 closes the assembly opening 18 of the damper chamber 19, which is further described below.

2 shows a longitudinal sectional view of the fuel high-pressure pump 1 according to Fig. 1 in which the pump cylinder 3 of the pump cylinder head 4 is located inside the tappet chamber 20 in the pump housing 2 As shown in Fig. A roller tappet 21 is inserted into a cylindrical tappet chamber 20 and the roller tappet is rotated on the rotation of the camshaft 10 on the double cam 9 of the camshaft 10 disposed in the drive unit chamber 8 The roller tappet 21 is translated in the tappet chamber 20 up and down as it rolls along with the roller 22 during exercise. A tappet spring 23 is disposed in the tappet chamber 20 so that the roller tappet 21 continuously contacts the double cam 9 of the camshaft 10 together with the roller 22, The spring is fixed between the pump cylinder head 4 and a holding disk disposed within the roller tappet 21. The grasping disc 24 is mounted on the inner ring seating surface 25 of the roller tappet 21 and at the same time a pump tappet 26 capable of translational movement in the pump cylinder guide 27, Is gripped with respect to the roller holder 29 of the roller tappet 21 by using the pump tappet base 28.

The supply port 13 (see FIG. 3) is connected to the drive unit chamber 8 via a supply channel 30 (see FIG. 5). The drive unit chamber 8 is connected to the damper chamber 19 on its side and the two chambers are connected to the tappet chamber 20 under the pump cylinder head 4 via the connection channels 31a and 31b . The connecting channel 31a has an extension 32 (FIG. 2) which extends into the seating face 33 of the pump housing 2 for seating the pump cylinder head 4. The extension 32 is subsequently advanced into the supply channel 34, which is recessed in the pump cylinder head 4 and connected to the electromagnetically operated suction valve 6. The electromagnetic operated suction valve 6 comprises an inlet valve 35 which is actuated by this suction valve and which is open in the pump cylinder head 4 in the open state, And connects the pump operation chamber 36 disposed in the extension of the cylinder guide 27 to the supply channel 34. [ As a result, during downward movement of the pump tappet 26 with the inlet valve 35 open, the fuel supplied through the supply port 13 enters the pump operation chamber 36, followed by the pump tappet 26 in the open state of the inlet valve 35 to the same low-pressure system. Then, when the inlet valve 35 is closed by the switching process of the electromagnetic operated valve 6, pressure is generated in the pump operation chamber 36, and the fuel in the pump operation chamber 36 is returned to the check valve 37 Pressure port 5 through the opening / closing valve (not shown). 5 also shows a return channel 43 which is connected to the return port 14 and which is connected to the pump housing 2 and the pump housing cover 11 for supporting the camshaft 10, To return to the low pressure system or tank the fuel that is guided for cooling and lubrication through the bearings disposed within the low pressure system.

Pressure pulsation, which must be damped in the fuel high-pressure pump 1, also takes place through the prescribed function of the above-described fuel high-pressure pump 1 and in a manner caused by the fuel low-pressure system. To this end, the damper chamber 19 incorporates the fluid damping device described below with reference to Figs. 2, 3 and 4. The fluid damping device comprises two membranes 38a, 38b in the illustrated embodiment, which are formed by a membrane, preferably a membrane formed as a punching bending part, with a membrane spring 39 made, for example, Is inserted into the holder (40). This preassembled membrane holder 40 is then inserted into the damper chamber 19 through the assembly opening 18 according to figure 4 and then the chamber cover 15 is fitted into the pump housing 2) and screws (17). Membranes 38a and 38b are formed annularly or cylindrically and include a membrane chamber 41 located inside and filled with a medium, e.g., a compressible gas. The two end faces 42 are deformed inward into the membrane chamber 41 when a force acts on the two annular end faces 42 facing each other of the two membranes 38a and 38b. This effect is used for damping pressure fluctuations or pressure pulsations predominantly present in the fuel high-pressure pump 1. Through the interior of the membranes 38a and 38b described above and the fuel supply through the feed channel 30 under the membranes 38a and 38b the membranes are oriented in the longitudinal direction 42) and is not pressed transversely (as opposed to the end face 42) as reproduced in Figure 6a as in conventional membranes.

Claims (11)

The pump cylinder guide 3 is provided with a pump cylinder head 2 having a pump cylinder head 4 having a pump cylinder 3 disposed therein. In the pump cylinder guide 27 of the pump cylinder 3, And a pump tappet 26 which interacts with a drive unit chamber 8 disposed in the pump housing 2 is arranged and the pump operation chamber 36 is connected to the drive unit chamber 8 via an electromagnetic operated suction valve 6 The high pressure pump comprising a fluid damper, the high pressure pump comprising:
Characterized in that the fluid damper is inserted into a damper chamber (19) which is recessed in the pump housing (2). The high pressure pump of claim 1, wherein the fluid damper is at least one membrane (38a, 38b). The high pressure pump according to claim 2, characterized in that the membranes (38a, 38b) comprise an internal membrane chamber (41) filled with medium. The high-pressure pump according to claim 2 or 3, characterized in that the membranes (38a, 38b) are pressurized by fluid pressure predominantly present in the damper chamber (19) at both sides. The high-pressure pump according to claim 4, characterized in that the membranes (38a, 38b) are pressed parallel to the end faces (42) of the membrane, which are positioned opposite each other. 6. A device according to any one of claims 2 to 5, characterized in that a supply port (13) for the supply of the medium to be transported by the high pressure pump is connected to the drive unit chamber (8) and a damper chamber ) Through which the fluid flows. 7. A high pressure pump according to any one of claims 2 to 6, characterized in that two or more membranes (38a, 38b) are inserted into the damper chamber (19) parallel to each other. 8. A device according to any one of the claims 2-7, characterized in that the membranes (38a, 38b) are inserted into the membrane holder (40) and the membrane holder can be inserted into the damper chamber (19) Pump. 9. High pressure pump according to any one of the preceding claims, characterized in that the damper chamber (19) comprises an assembly opening (18) which can be covered by a chamber cover (15). 10. A method according to any one of claims 1 to 9, characterized in that the drive unit chamber (8) is connected to a damper chamber (19) and the two chambers are connected via a connecting channel (31a, 31b) Is connected to the lower tappet chamber (20). A fuel injection system comprising a high-pressure pump formed as a fuel high-pressure pump (1) according to any one of claims 1 to 10.

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