WO2020083548A1

WO2020083548A1 - High-pressure pump arrangement

Info

Publication number: WO2020083548A1
Application number: PCT/EP2019/073572
Authority: WO
Inventors: Jochen Aleker
Original assignee: Robert Bosch Gmbh
Priority date: 2018-10-22
Filing date: 2019-09-04
Publication date: 2020-04-30
Also published as: DE102018217990A1

Abstract

The invention relates to a high-pressure pump arrangement (7) having at least two pump elements (13, 14), which are used to provide pressurized fuel for a high-pressure accumulator, and having a fluidic section (19) between a metering unit (9) and two intake valves (15, 16) of the pump elements (13, 14), the fluidic section (19) comprising a connecting volume (30) with an inlet (35) assigned to the metering unit (9) and two outlets (31, 32) assigned to the intake valves (15, 16), with a fluid flow (33) flowing through the connecting volume (30) to fill the high-pressure accumulator between the inlet (35) and outlets (31, 32) thereof. To improve the delivery volume characteristics of the high pressure pump arrangement (7), a flow deflection device (22) is arranged in the connecting space (30) and has a plurality of fluid passage openings (23), through which the fluid flow (33) is so deflected that fluid energy is converted.

Description

description

title

High pressure pump arrangement

The invention relates to a high-pressure pump arrangement with at least two pump elements, which serve to provide high-pressure fuel for a high-pressure accumulator, and with a fluidic path between a metering unit and two sucking valves of the pump elements, the fluidic path connecting a space with one of the

The input assigned to the measuring unit and two outputs assigned to the infant valves, the connecting space for filling the

High-pressure accumulator between its input and its outputs is flowed through by a fluid flow. The invention further relates to a

Method for operating such a high-pressure pump arrangement in a fuel injection system.

State of the art

From the German published application DE 10 2010 062 159 Al is a

High-pressure injection system for an internal combustion engine is known, in particular for a motor vehicle, comprising a high-pressure pump, a high-pressure rail, preferably a prefeed pump for conveying fuel from a fuel tank to the high-pressure pump, fuel not required by the high-pressure pump being fed back into the line through a fuel return line

Fuel tank is returned, with a metering unit that the

High-pressure pump supplied amount of fuel controls and / or regulates, so that in a further embodiment, the fuel return line can be dispensed with.

Disclosure of the invention The object of the invention is to provide the delivery rate characteristic of a high-pressure pump arrangement with at least two pump elements which serve to provide high-pressure fuel for a high-pressure accumulator and with a fluidic path between a metering unit and two sucking valves of the pump elements, the fluidic path connecting a space with a comprises the input assigned to the metering unit and two outputs assigned to the infant valves, the

Connection space for filling the high pressure accumulator between his

To improve the entrance and its outputs through a fluid flow.

The object is in a high-pressure pump arrangement with at least two pump elements which serve to provide high-pressure fuel for a high-pressure accumulator, and with a fluidic path between a metering unit and two sucking valves of the pump elements, the fluidic path connecting a space with one of the

High-pressure accumulator between its entrance and its exits is flowed through by a fluid flow, in that a flow deflection device is arranged in the connection space, which has a plurality of

Has fluid passage openings through which the fluid flow is deflected so that fluid energy is converted. The conversion of the fluid energy with the aid of the flow deflection device is also referred to as dissipation. Fluid energy, in particular kinetic energy, is advantageously converted into heat by friction and thus during operation of the

High pressure pump arrangement deliberately destroyed. The fluid is, for example, fuel. The fuel is, for example, a hydraulic medium such as gasoline or diesel fuel. However, the fuel may also be a gaseous fuel. The at least two pump elements are advantageously driven by a common drive shaft. The infant valves can also be referred to as intake valves. Outlet valves of the pump elements are also referred to as pressure valves or high pressure valves. The high-pressure accumulator is also known as a rail or common rail. The two pump elements are used, for example, to represent an in-line piston pump with at least two pump elements which are spaced apart in the axial direction on a drive shaft. With regard to the fluid passage openings of the flow deflection device, a plurality advantageously means more than ten, preferably significantly more than ten.

If the high-pressure pump arrangement is operated with diesel fuel, then the high-pressure pump arrangement with the two pump elements is also referred to as a diesel high-pressure pump. High-pressure diesel pumps are usually suction throttled to control the flow rate or operated with a metering unit. The inlet valves for the pump elements, which are also referred to as high-pressure elements, are designed, for example, as spring-assisted check valves, which are referred to as infant valves. The spring-assisted check valves or infant valves are generally designed with relatively lower spring forces and spring rates, in order to enable adequate filling even when the pressure supply is poor, in particular when the internal combustion engine starts hot. In the construction of conventional high-pressure pump arrangements, this leads, among other things, to the fact that these sucking valves close very slowly because little spring force is available. Thus, at the start of delivery, a desired backflow effect can occur, in which part of the amount of fuel in the respective high-pressure element is returned through the not yet closed feeding valve into the valve

Flow direction flows back in front of the area. These

Part of the fuel flowing back is referred to as the loss quantity wave. In the operation of conventional high-pressure pump arrangements, pressure is built up and the respective one only after the infant valve has been closed

Pressure valve or outlet valve or high pressure outlet valve opened. Only then is the regular delivery stroke carried out in conventional high-pressure pump arrangements. The fluidic route between the

High-pressure pump after the metering unit and before the baby valves is also referred to as a gallery. The loss wave can be in the operation of

Conventional high-pressure pump arrangements lead to pressure vibrations occurring in the area of the gallery, which disrupt the filling process and the sucking valve of the second pump element, which is also referred to as a high-pressure element. In extreme cases, the loss wave caused pressure vibrations to apply an additional force to a slider in the metering unit so that it is stationary

Leaves target position unintentionally. This in turn can lead to increased instabilities in the high-pressure delivery rate, which are difficult or impossible to control using a rail pressure regulator.

The flow deflecting device provides a component that has an overall rather large flow cross section through the many small ones

Represents fluid passage openings. The overall large flow cross-section or opening cross-section of the flow deflection device enables the pump elements or to be filled in a simple manner

High pressure elements with sufficient fuel. The many little ones

Fluid passage openings ensure that the fluid flow through the connection space is stabilized in the case of pulsating volume waves. This is advantageously achieved in that part of the energy of the pulsating bulk waves is converted by dissipation. The flow deflection device can be manufactured inexpensively from metal or, if appropriate, from plastic. The flow deflection device advantageously does not itself comprise an elastic element, so that there are no dynamic load requirements for the

Flow deflection devices arise.

A preferred embodiment of the high-pressure pump arrangement is characterized in that the fluid passage openings

Have flow cross sections that are at least ten times smaller than a total flow cross section of the connection space. The connection space is, for example, a hole in a housing body

High pressure pump arrangement executed. This hole, which is also known as the Gallery Bore, has a diameter of ten millimeters, for example. The fluid passage openings of the flow deflection device have a diameter of 0.2 millimeters, for example. The fluid passage openings are designed as bores, for example. They are particularly advantageous

Fluid passage openings Flow cross sections that are at least forty times smaller than the total flow cross section of the connection space. In experiments carried out within the scope of the present invention and

Research has found that a relationship between the Total flow cross section and the respective flow cross sections of the fluid passage openings is particularly advantageously one in fifty.

Another preferred exemplary embodiment of the high-pressure pump arrangement is characterized in that the flow deflection device comprises a semi-finished product with the fluid passage openings, which is arranged in the connecting space between the inlet and the outlet. The semi-finished product is, for example, a bent or punched sheet material. The semifinished product can also be a wire mesh or a deep-drawn sleeve made of sheet metal.

A further preferred exemplary embodiment of the high-pressure pump arrangement is characterized in that the flow deflection device comprises an elongated hollow body with an interior space which extends over the

Fluid passage openings is fluidly connected to an annular space which surrounds the hollow body in the connecting space. The annular space advantageously extends in the axial direction beyond the two exits of the connecting space. In this way, it is advantageously achieved that the fluid flow is directed through the interior and the fluid passage openings to the exits. A

Bypassing the fluid passage openings of the flow deflection device is advantageously not possible for the fluid flow. This creates a desired breakwater function for fluid flow with the

Flow deflection device provided.

A further preferred exemplary embodiment of the high-pressure pump arrangement is characterized in that the elongated hollow body is axially in the

Connection room is arranged. The terms axial and radial refer to a longitudinal axis of the essentially circular cylindrical connection space.

The elongated hollow body essentially has the shape of a

Circular cylinder jacket which delimits the interior on the inside and delimits the annular space on the outside, which delimits in the radial direction between the hollow body and a housing body which serves to represent the connection space. Another preferred exemplary embodiment of the high-pressure pump arrangement is characterized in that the elongated hollow body and the

Connection space each have a circular cross section. As a result, a flow deflection device that is simple in terms of construction and production technology is created in a simple manner.

A further preferred exemplary embodiment of the high-pressure pump arrangement is characterized in that the elongated hollow body is attached to one of the

Entrance of the connecting room facing end is open. This ensures the unimpeded entry of the fluid flow into the elongated hollow body in a simple manner. The end of the elongated hollow body facing away from the entrance space is preferably made closed. The closed end of the elongated hollow body can optionally be equipped with fluid passage openings.

Another preferred exemplary embodiment of the high-pressure pump arrangement is characterized in that the flow deflection device is formed from a sheet metal material. The sheet material is preferably a non-ferrous material in which the fluid passage openings are designed, for example, as bores. A bending process on the sheet metal material is advantageous after the drilling of the holes to show the

Flow deflection device executed.

The invention also relates to a method for operating a previously

described high pressure pump assembly in a fuel injection system.

The invention optionally also relates to a fuel injection system with a high-pressure pump arrangement described above.

The invention further relates to a flow deflection device, in particular a semifinished product or an elongated hollow body, for a high-pressure pump arrangement described above. The parts mentioned can be traded separately. The invention optionally also relates to a kit for a high-pressure pump arrangement described above. The flow deflection device provides, among other things, the advantage that it can also be used in conventional

High pressure pump assemblies can be used in the

Connection space to represent the desired flow deflection.

Further advantages, features and details of the invention emerge from the following description, in which various exemplary embodiments are described in detail with reference to the drawing.

Brief description of the drawing

Show it:

Figure 1 is a schematic representation of a high pressure injection system for injecting fuel in an internal combustion engine, with a

High-pressure pump arrangement, which comprises at least two pump elements, which serve to supply high-pressure fuel for one

To provide high pressure storage;

Figure 2 shows an embodiment of a flow deflection device for a high pressure pump arrangement, as shown in Figure 1, in one

Top view; and

Figure 3 is an enlarged view of a section of Figure 1 with a connecting space, which is arranged between a metering unit and two sucking valves of pump elements of a high-pressure pump arrangement, as shown in Figure 1, and equipped with a flow deflection device, as shown in Figure 2 .

Description of the embodiments

FIG. 1 shows a schematic illustration of a high-pressure injection system 1 of an internal combustion engine (not shown) of a motor vehicle, which is also referred to as an internal combustion engine. The high pressure injection system or fuel injection system 1 comprises one

High-pressure fuel accumulator 2, which is also referred to as a high-pressure rail or common rail. The high-pressure fuel accumulator 2 comprises a

Fuel rail 3, from which high-pressure fuel is injected via valves (not shown) into the combustion chamber or the combustion chambers of the internal combustion engine.

A prefeed pump 4 delivers fuel from a fuel tank 5 via a filter device 10 through a fuel line 6 to one

High-pressure pump arrangement 7. The high-pressure pump arrangement 7 comprises two pump elements 13, 14, which are also referred to as high-pressure pump elements.

The high-pressure pump elements 13, 14 are driven, for example, together with the prefeed pump 4 via a common drive shaft. The drive shaft is coupled to a crankshaft of the internal combustion engine, for example. The fuel delivered by the prefeed pump 4 is passed through the fuel line 6 to the pump elements 13, 14

High pressure pump assembly 7 passed.

The fuel that is not required by the high-pressure pump arrangement 7 is returned to the fuel tank 5 through a fuel return line 8. A metering unit 9 controls or regulates the amount of fuel supplied to the high-pressure pump arrangement 7, so that, if necessary, the

Fuel return line 8 can be dispensed with.

An optionally indicated hydraulic resistance 11 serves, for example, to represent a so-called zero-feed throttle. A valve device 12 serves to represent an overflow valve in a low pressure area. A rectangle 20 indicates a pressure control valve or pressure relief valve for the high pressure in the high-pressure fuel accumulator 2.

A dashed rectangle 19 in FIG. 1 indicates a fluidic path, which is also referred to as a gallery. The fluidic path 19 is as can also be seen in FIG. 3, between the metering unit 9 and infant valves 15, 16 of the two pump elements 13, 14.

The fuel provided with the aid of the prefeed pump 4 reaches the pump elements 13, 14 via the sucking valves 15, 16

High pressure is applied to the fuel in pump elements 13, 14. The high-pressure fuel passes from the pump elements 13, 14 via pressure valves 17, 18 into the high-pressure fuel reservoir 2.

In FIG. 3 it can be seen that the fluidic path comprises a connection space 30 with two exits 31, 32 and one entry 35. The input 35 of the connection space 30 is assigned to the metering unit 9. An arrow 33 in FIG. 3 indicates a fluid flow that flows into the connection space 30 via the metering unit 9 and the inlet 35 of the fluidic path 19.

The connection space 30 is, for example, a bore 34 in one

Housing body of the high pressure pump assembly (7 in Figure 1) executed. The output 31 of the connection space 30 is the sucking valve 15 of the

Pump element 13 assigned. The outlet 32 of the connection space 30 is assigned to the sucking valve 16 of the pump element 14. A line 38 in FIGS. 2 and 3 indicates a longitudinal axis of the connecting space 30 designed as a bore 34.

A flow deflection device 22 is located in the connection space 30

arranged. The flow deflection device 22 is designed, for example, as a semifinished product 36 and has a multiplicity of fluid passage openings 23

fitted.

In FIG. 2 it can be seen that the flow deflecting device 22 comprises, for example, an elongated hollow body 24 which essentially has the shape of a straight circular cylinder jacket. The elongated hollow body 24 comprises an inner space 25 which communicates with the fluid through the openings 23

Annulus 26 communicates. As can be seen in FIG. 3, the annular space 26 is delimited radially on the inside by the elongated hollow body 24 and radially on the outside by the bore 34. The outputs 31, 32 to the infant valves 15, 16 are connected to the annular space 26. The elongated hollow body 24 has a closed end 27 on the right in FIGS. 2 and 3. The left end of the elongated hollow body in FIGS. 2 and 3

24 is open. The open end of the elongated hollow body 24 is designed as a fastening end 28 in the exemplary embodiment shown.

At the fastening end 28, the elongated hollow body 24 has a larger outer diameter. With the larger outside diameter it is

Fastening end 28, as can be seen in FIG. 3, is pressed into the bore 34 in the region of the inlet 35 of the connection space 30. So it can

Flow deflector 22 in a simple manner in the

Connection room 30 are mounted.

Alternatively or additionally, the closed end 27 of the elongated hollow body 24 can be fixed in the bore 34. Alternatively or additionally, the elongated hollow body 24 can be fastened in the middle between its two ends 27, 28 in the bore 34.

Claims

Expectations

1. High-pressure pump arrangement (7) with at least two pump elements (13, 14) that serve to provide high-pressure fuel for a high-pressure accumulator (2) and with a fluidic path (19) between a metering unit (9) and two sucking valves ( 15, 16) of the pump elements (13, 14), the fluidic path (19) being one

Connection space (30) having an input (35) assigned to the metering unit (9) and two outputs (31, 32) assigned to the infant valves (15, 16), the connection space (30) for filling the

High-pressure accumulator (2) between its entrance (35) and its

Outputs (31, 32) are flowed through by a fluid flow (33), characterized in that in the connecting space (30)

Flow deflection device (22) is arranged, which has a plurality of fluid passage openings (23) through which the fluid flow (33) is deflected so that fluid energy is converted.

2. High-pressure pump arrangement according to claim 1, characterized in that the fluid passage openings (23) have flow cross sections which are at least ten times smaller than a total flow cross section of the connection space (30).

3. High-pressure pump arrangement according to one of the preceding claims, characterized in that the flow deflection device (22) comprises a semifinished product (36) with the fluid passage openings (23), which in the connecting space (30) between the input (35) and the outputs (31, 32) is arranged.

4. High-pressure pump arrangement according to one of the preceding claims, characterized in that the flow deflection device (22) comprises an elongated hollow body (24) with an interior (25) which is fluidically connected via the fluid passage openings (23) to an annular space (26) surrounds the hollow body (24) in the connection space (30).

5. High-pressure pump arrangement according to claim 4, characterized in that the elongated hollow body (24) is arranged axially in the connecting space (30).

6. High-pressure pump arrangement according to claim 4 or 5, characterized

characterized in that the elongated hollow body (24) and the

Connection space (30) each have a circular cross section.

7. High-pressure pump arrangement according to one of claims 4 to 6, characterized in that the elongated hollow body (24) is open at an end facing the entrance (35) of the connecting space (30).

8. High-pressure pump arrangement according to one of the preceding claims, characterized in that the flow deflection device (22) is formed from a sheet metal material.

9. A method for operating a high-pressure pump arrangement (7) according to one of the preceding claims in a fuel injection system (1).

10. flow deflection device (22), in particular semi-finished product (36) or

elongated hollow body (24), for a high-pressure pump arrangement (7) according to one of claims 1 to 8.