WO2014019904A1

WO2014019904A1 - High-pressure pump for internal combustion engines

Info

Publication number: WO2014019904A1
Application number: PCT/EP2013/065587
Authority: WO
Inventors: Friedrich Boecking
Original assignee: Robert Bosch Gmbh
Priority date: 2012-08-01
Filing date: 2013-07-24
Publication date: 2014-02-06
Also published as: EP2880297B1; CN104508293A; CN104508293B; IN2014DN10748A; EP2880297A1; DE102012213546A1

Abstract

The invention relates to a suction valve (2) which is used for a high-pressure pump (1), which is used in particular for air-compressing, self-igniting internal combustion engines. The suction valve (2) comprises a valve closing body (15), which interacts with a sealing seat (13), and an armature (30), which can be magnetically actuated and which is connected to the valve closing body (15). A pressure stage is provided, by means of which the valve closing body (15) can be loaded in an opening direction (28). Furthermore, the armature (30) can be magnetically actuated in such a way that the valve closing body (15) can be loaded against the sealing seat (13) in the closing direction (33) by a magnetic closing force by means of the armature (30). Furthermore, a high-pressure pump (1) having such a suction valve (2) is specified. By means of this embodiment, the activation energy for the suction valve (2) can be reduced.

Description

description

title

High pressure pump for internal combustion engines State of the art

The invention relates to a suction valve for a high-pressure pump, which is used in particular for air-compressive, self-igniting internal combustion engines, and a high-pressure pump, in particular a radial or in-line piston pump. The high-pressure pump can also serve as a piston pump for conveying other suitable liquids.

From DE 10 2010 027 745 A1 a high-pressure pump is known, which serves in particular as a radial or in-line piston pump for fuel injection systems of air-compressing, self-igniting internal combustion engines. In this case, an inlet valve is provided, via which a metering of a guided into a pump working space fuel is possible. This can be done a full filling of the pump working space. However, a partial filling of the pump working space can be achieved by a suitable control of the inlet valve. The actuation takes place by energizing a magnetic coil. Specifically, when the solenoid is deenergized, the force of a valve spring can initiate a closing of the inlet valve largely without delay. The valve spring acts via a valve element and a shim on an anchor, which is connected to a valve lifter. Thus, the valve stem is biased by the bias of the valve spring. The valve spring acts on the valve stem against the

Valve seat.

In the case of the high-pressure pump known from DE 10 2010 027 745 A1, it is therefore possible, by actuating the inlet valve, to supply fuel from a low-pressure space into the engine

Pump work space are led. The actuation of the inlet valve takes place here during a suction stroke of the pump piston. During the delivery of the

Pump piston, the inlet valve is preferably closed. Thus, an intake valve is realized, which is closed in the de-energized state. About a correspondingly high spring preload of the valve spring, a high closing dynamics can be achieved. However, this embodiment has the disadvantage that for opening and keeping open the Inlet valve solenoid coil must be energized. Especially at a high

Spring preload, which is used for the high closing dynamics, a correspondingly strong magnetic field is required, which causes high currents and thus large power losses. This results in the known design large driving energies, as over the entire suction phase, the inlet valve must be kept open.

Disclosure of the invention

The suction valve according to the invention with the features of claim 1 and the

High-pressure pump according to the invention with the features of claim 8 have the advantage that an improved control for the metering of fuel is made possible. In particular, energy consumption and the drive energy thus required can be reduced. The measures listed in the dependent claims are advantageous

Further developments of the suction valve specified in claim 1 and the high pressure pump specified in claim 8 possible.

About the pressure level of the valve closing body can be acted upon in the opening direction. In the closing direction, which is oriented counter to the opening direction, is the

Valve closing body acted upon by the magnetic closing force via the armature. The magnetic closing force therefore serves to support the closing of the suction valve. Preferably, the closing movement is initiated so far by the magnetic closing force that the suction valve passes from a de-throttled state in the throttling. In the throttling closing is then supported by the hydraulic forces or even at least largely conditional. The magnetic clamping force is therefore no longer needed in an advantageous manner at the end of the closing process. This improves the control of the suction valve. In particular, the

Power consumption and the required drive energy reduced to close.

It is advantageous that a guide diameter for guiding the valve closing body is smaller than a seat diameter of the sealing seat. As a result, the pressure stage can act on the valve closing body in the opening direction with an effective force as a function of the prefeed pressure. With a correspondingly large prefeed pressure and at the same time a reduced pressure in the pump working chamber, the pressure opening causes the suction valve to open, so that fuel is conducted into the pump working chamber via the opened sealing seat. It is also advantageous that the valve closing body is connected via a connecting bolt (valve pin) with the armature that the

Connecting bolt is guided in a guide bore with the guide diameter, that between the guide bore and the sealing seat, a valve space is formed, in which under a Vorförderdruck fuel is feasible, that an armature space in which the armature is disposed, guided by the guided in the guide bore

Connecting bolt is separated from the valve chamber and that the armature space is relieved of pressure in relation to the feed pressure. Thus, the prefeed pressure of the fuel in the valve chamber can advantageously bring about an effective force in the opening direction, which, however, is directed counter to a force dependent on the pressure in the pump working space in the closing direction. However, during the suction stroke of the pump piston of the high-pressure pump, the pressure in the pump working space is reduced, so that in the sum of an opening force in the opening direction, which allows the inflow of fuel under the prefeed pressure in the pump working space.

Advantageously, a valve spring can be provided, which acts on the valve closing body at least indirectly in the closing direction. In this case, it is further advantageous that the valve spring is arranged in an armature space in which the armature is arranged, and / or that the valve spring acts on the valve closing body by means of the armature and / or a valve pin which connects the armature to the valve closing body. The closing spring defines for a starting position of the suction valve. On the other hand, can be generated in the closing direction via a choice of the spring constant of the closing spring and a predetermined bias with the deflection and thus the opening stroke increasing spring force. This allows tuning of the suction valve.

In addition, it is advantageous that a control is provided which causes the magnetic actuation of the armature by energizing a solenoid during a closing stroke of the valve closing body, wherein the controller deenergizes the solenoid before a complete closing of the sealing seat. This reduces the required drive energy. This also reduces the cooling requirement for the solenoid coil. In this case, it is also advantageous that the control actuates the valve closing body by energizing the solenoid during the closing stroke of the valve closing body, until a throttling is achieved at the sealing seat. When the restriction at the sealing seat is reached, then the further closing stroke can be closed purely mechanically by the increasing interior pressure of the pump working space.

Thus, advantageously in a suction stroke of the pump assembly, in which a pressure in the pump chamber is reduced, acting on the at the pressure stage Prefetching be allowed to actuate the valve closing body in the opening direction. Further, in a delivery stroke of the pump assembly in which a pressure in the pump working space is increased, the valve closing body of the pressure in

Pumping workspace are actuated in the closing direction when the valve closing body is actuated so far in the closing direction by the magnetic actuation of the armature that a restriction is achieved at the sealing seat.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will be explained in more detail in the following description with reference to the accompanying drawings, in which corresponding elements are given identical reference numerals. It shows:

1 shows a high-pressure pump with a suction valve in a partial, schematic sectional view according to an embodiment of the invention.

Fig. 2 is a diagram for explaining the operation of the high-pressure pump and the suction valve according to the embodiment of the invention; Fig. 3 is another diagram for explaining the operation of the high pressure pump and the suction valve according to the embodiment of the invention.

Fig. 4 is another diagram for explaining the operation of the high pressure pump and the suction valve according to the embodiment of the invention.

Embodiments of the invention

Fig. 1 shows a high-pressure pump 1 in an abstract, schematic

Sectional view according to an embodiment of the invention. The

High-pressure pump 1 can be designed in particular as a radial or in-line piston pump. Specifically, the high-pressure pump 1 is suitable as a fuel pump for

Fuel injection systems of air-compressing, self-igniting internal combustion engines. The high-pressure pump 1 has a suction valve 2. The suction valve 2 is particularly suitable for use in such high-pressure pumps 1. The suction valve 2 according to the invention is suitable in a suitably adapted modification, however, also for others

Use cases. A preferred use of the high pressure pump 1 and the suction valve 2 is for a fuel injection system with a fuel rail, which stores diesel fuel under high pressure. However, other suitable liquids, including other liquids than fuel, controlled by the suction valve 2 and of the

Be promoted high-pressure pump 1.

The high-pressure pump 1 has a cylinder head 3, in which a pump working space 4 of a pump assembly 5 is formed. Here, in the cylinder head 3 is a

Cylinder bore 6 configured in which a pump piston 7 is guided. The pump piston 7 bounded in the cylinder bore 6, the pump working space 4. Further, a drive shaft 8 is mounted with a cam 9 in a housing, not shown. In operation, the drive shaft 8 rotates about its axis of rotation 10. This occurs via the cam 9 to an actuation of the pump piston 7, which is illustrated by the double arrow 1 1. The actuation can take place, for example, via a roller mounted in a roller shoe.

The suction valve 2 has a valve seat body 12 on which a sealing seat 13 is configured. The sealing seat 13 is circular in this embodiment with a

Seat diameter 14 configured. Here, a valve closing body 15 is provided which cooperates with the sealing seat 13 of the valve seat body 12.

The valve seat body 12 is fixed to the cylinder head 3 via a plug screw. Here, a seal between the valve seat body 12 and the cylinder head 3 is formed, so that the pump chamber 4 is sealed against the environment high pressure resistant.

The suction valve 2 has a valve space 20 into which fuel is conveyed via one or more bores 21, 22 under a prefeed pressure. In the closed state, the valve closing body 15 is located on the one hand on the sealing seat 13 with the

Seat diameter 14 at. Further, the valve closing body 15 is connected to a valve pin 23 or designed in one piece with this. The valve pin 23 is in one

Guide bore 24 of a body 25 which may be configured as a magnetic core out. The guide bore 24 in this case has a guide diameter 26 which is smaller than the seat diameter 14 of the sealing seat 13. An armature space 27, in which the valve pin 23 protrudes, is pressure-relieved against the prefeed pressure in the valve chamber 20. Thus, a pressure level is formed, the over the seat diameter 14 of the sealing seat 13 and the

Guide diameter 26 of the guide bore 24 is determined. Due to the

Prefetching pressure therefore results at the pressure stage in a direction of opening 28 along an axis 29 of the valve pin 23 directed force. The suction valve 2 also has an armature 30, which is connected to the valve pin 23 and arranged in the armature space 27. In addition, a magnetic coil 31 is provided which can be energized by a controller 32. When energizing the

Magnetic coil 31 generates this a magnetic force on the armature 30, whereby the

Valve-closing body 15 in a closing direction 33, which is oriented counter to the opening direction 28, is acted upon in the direction of the sealing seat 13 of the valve seat body 12.

In this embodiment, a valve spring 34 is also provided, which acts on the valve closing body 15 via the armature 30 and the valve pin 23 in the closing direction 33.

The design and operation of the high pressure pump 1 and the suction valve 2 are described below with reference to FIGS. 2, 3 and 4. 2, 3 and 4 each show a diagram for explaining the operation of the

High pressure pump 1 and the suction valve 2. In FIG. 2, the abscissa represents the stroke of the valve closing body in the opening direction 28, while the ordinate indicates the flow dependent on the stroke. In FIG. 2, the stroke of the valve closing body 15 in the opening direction 28 is plotted on the abscissa, while the forces acting on the valve closing body 15 in the closing direction 33 are plotted on the ordinate. In Fig. 4, the time is plotted on the abscissa, while at the ordinate, a pressure in the pump chamber 4, the stroke of the valve closing body 15 in the opening direction 28 and energization of the magnetic coil 31 are applied. 2, a curve 40 is shown as an example, the flow 40 between the valve closing body 15 and the sealing seat 13 from the valve chamber 20 in the

Pump workspace 4 illustrated. When the stroke exceeds a value 41, then the suction valve 2 is in the Entschrosselten phase, which is illustrated in Fig. 2 by an area 42. Below the value 41, the suction valve 2 is in the throttling, which is illustrated by an area 43. When the stroke disappears, the flow 40 also disappears.

To explain the Fig. 3 is assumed a state 44 in which the suction valve 2 is in the de-throttled region 42 and in which a comparatively large, in particular maximum, stroke of the valve closing body 15 is achieved. By a curve 45, a possible course of the spring force of the valve spring 34 is shown in the

Closing direction 33 acts on the valve closing body 15. Ordinatenschnittpunkt 46 of the curve 45 with the ordinate indicates a non-vanishing bias. The Preload of the valve spring 44 can be suitably chosen here. Likewise, the slope of the curve 45 can be preset via the spring constant of the valve spring 34. In state 44, the restoring force is initially applied essentially by the valve spring 34. If the pressure conditions in the valve chamber 20 and in the pump working chamber 4 allow this, which is the case for example in a delivery stroke of the pump piston 7, then the valve closing body 15 closes due to the restoring force of the valve spring 34, so that a curve 47 first in the vicinity of the curve 45th is traversed, with the direction of the curve is indicated by the arrow 47. In a region 48, the magnetic coil 31 is energized by the controller 32. This increases the on the

Valve closing body 15 acting in the closing direction 33 closing force sharply, which is illustrated by the arrow 49. As a result, a maximum force 50 on the

Valve closing body 15 exerted. In this case, the value falls below 41, so that the suction valve 2 enters the throttled region 43. Here, the stroke further decreases, which is illustrated by the arrow 51. When the energization of the magnetic coil 31 ends, which is illustrated by the area 48, then the suction valve 2 is already within the throttled area 43. In a region 52, the further closing force can therefore be determined by the valve spring 34 and the rising pressure of the

Pump working space 4 are applied. In a vanishing stroke, in which the suction valve 2 and the sealing seat 13 is closed, there remains a closing force given by the ordinate intersection point 53 of the curve 47 with the ordinate. This results from the bias of the valve spring 34 and the pressure stage. Of the

Ordinatenschnittpunkt 43 thus depends on the prefeed pressure (flow pressure).

This results in a comparatively narrow region 48, in which a current supply of the magnetic coil 31 is required. Thus, the power consumption is significantly reduced.

4 shows time intervals 48 ', 48 "in which the magnetic coil 31 is energized, and the current supply 54 is therefore characterized by a curve 54 with rapidly rising and falling edges.

By a curve 55, the pressure in the pump working space 4 is illustrated. This increases in the time intervals 48 ', 48 "in each case, wherein the increasing pressure in the

Pump work 4 each closing the suction valve 2 in the throttled region 43 is supported. After closing the suction valve 2, the pressure continues to increase, which is due to the delivery stroke of the pump piston 7. The curve 56 illustrates the course of the stroke of the valve closing body 15. For ease of illustration, the curves 54, 55, 56 start from a common level, the output values at this level are not necessarily equal to zero. Thus, the suction valve 2 is designed as an outwardly opening valve 2 with a pressure stage. Is the interior pressure in the pump working space 4 smaller than that

Pre-delivery pressure in front of the suction valve 2, the valve closing body 15 opens against the valve spring 34. The pump working chamber 4 is filled until the suction valve 2 is electrically pulled out by energizing the solenoid coil 31 from the de-throttled phase. The further closing stroke can then be carried out purely mechanically by the increasing interior pressure of the pump working chamber 4, since the suction valve 2 is in the throttling. The advantage thus results in a very short drive time at a small Hubdelta to activate the closing movement of the suction valve 2.

Depending on the configuration of the suction valve 2 or the controller 32, the region 48 can thus also include the initial state 44. Closing the

Suction valve 2 is then initiated immediately by energizing the solenoid coil 31.

The invention is not limited to the described embodiments.

Claims

claims

1 . Suction valve (2) for a high-pressure pump (1), which is used in particular for air-compressing, self-igniting internal combustion engines, with a valve closing body (15) which cooperates with a sealing seat (13), and a magnetically actuated armature (30) which is connected to the valve closing body (15) is connected,

characterized,

that a pressure stage is provided, via which the valve closing body (15) in an opening direction (28) can be acted upon, and that the armature (30) is magnetically actuated, that the valve closing body (15) via the armature (30) of a

magnetic closing force in a closing direction (33) against the sealing seat (13) can be acted upon.

2. Suction valve according to claim 1,

characterized,

a guide diameter (26) for guiding the valve closing body (15) is smaller than a seat diameter (14) of the sealing seat (13).

3. Suction valve according to claim 2,

characterized,

in that the valve closing body (15) is connected to the armature (30) via a valve pin (23), that the valve pin (23) in a guide bore (24) with the

Guide diameter (26) is guided, that between the guide bore (24) and the sealing seat (13), a valve space (20) is formed, in which under a prefeed pressure fuel is feasible, that an armature space (27), in which the armature ( 30) through which in the guide bore (24) guided valve pin (23) is separated from the valve chamber (20) and that the armature space (27) with respect to the

Pre-delivery pressure is relieved of pressure.

4. Suction valve according to one of claims 1 to 3,

characterized,

a valve spring (34) is provided which acts on the valve closing body (15) at least indirectly in the closing direction (33).

5. Suction valve according to claim 4,

characterized,

in that the valve spring (34) is arranged in an armature space (27) in which the armature (30) is arranged and / or in that the valve spring (34) the valve closing body (15) by means of the armature (30) and / or a valve pin (23), the anchor (30) with the

Valve closing body (15) connects, acted upon.

6. Suction valve according to one of claims 1 to 5,

characterized,

in that a control (32) is provided which controls the magnetic actuation of the armature (30) by energizing a magnetic coil (31) during a closing stroke of the armature (30)

Valve Schließkorpers (15) causes, wherein the controller (32), the solenoid (31) de-energized before a complete closing of the sealing seat (13).

7. Suction valve according to claim 6,

characterized,

in that the control unit (32) actuates the valve closing body (15) by energizing the solenoid coil (31) during the closing stroke of the valve closing body (15) until throttling is achieved on the sealing seat (13).

8. High-pressure pump (1), in particular radial or inline piston pump for

Fuel injection systems of air-compressing, self-igniting internal combustion engines, comprising at least one cylinder head (3), a pump assembly (5) comprising a pump working space (4) formed in the cylinder head (3), and at least one suction valve (2) according to one of claims 1 to 7 , wherein via the sealing seat (13) of the suction valve (2) fuel in the pump working space (4) can be guided.

9. High-pressure pump according to claim 8,

characterized,

in the case of a suction stroke of the pump assembly (5), in which a pressure in the

Pump working space (4) is reduced, acting on one of the pressure stage

Prefetching an actuation of the valve closing body (15) in the opening direction (28) is possible.

10. High-pressure pump according to claim 8 or 9,

characterized,

that during a delivery stroke of the pump assembly (5), in which a pressure in the

Pump working space (4) is increased, the valve closing body (15) of the pressure in Pump working space (4) in the closing direction (33) is actuated when the valve closing body (15) is actuated so far in the closing direction (33) by the magnetic actuation of the armature (30) that a throttling at the sealing seat (13) is reached ,