EP1394403A2 - Fuel system for an internal combustion engine - Google Patents

Abstract

Fuel system comprises a low-pressure region (18), a high-pressure fuel pump (24), and a high-pressure region (26). The high-pressure fuel pump consists of a housing (38, 42), at least one moving conveying element (44) defining a conveying chamber (66), at least one drive (54) setting the conveying element in motion, a drive chamber (62) in which the drive is at least partly arranged, and a lubricant supply device (45) for supplying moving parts with fuel as a lubricant. The lubricant supply device loads the drive with a pressure which is higher than the pressure in the low-pressure region. An Independent claim is also included for an alternative fuel system.

Description

State of the art

The invention relates to a fuel system for a Internal combustion engine with a low pressure area, one High pressure fuel pump, and a high pressure area, the high pressure fuel pump comprising: a housing, at least one movable conveyor element, which one Delivery space limited, at least one drive that the Conveyor element can set in motion Drive room in which the drive is at least partially is arranged, and a lubricant supply device to supply moving parts with Fuel as a lubricant.

Such a fuel system is known from DE 197 05 205 A1 known. In this a radial piston pump is shown, the Fuel from an electric pre-feed pump with a certain form is supplied. The radial piston pump compresses the fuel to a very high level. The Pistons of the radial piston pump are driven by a compression spring by means of sliding shoes against a lifting ring, the is placed on a rotating eccentric shaft. Over a The bore in the piston and in the sliding block is the delivery chamber of a cylinder connected to a relief chamber, the between the slide shoe and the corresponding contact surface the cam ring is arranged. In this way, one Delivery stroke of the piston of the relief chamber with pressure acted upon and thereby the contact force of the sliding block reduced on the contact surface of the cam ring.

In the known piston pump, eccentric shaft, cam ring, Sliding shoe, etc., arranged in a drive room that with connected to the low pressure area and in the under pressure standing fuel is present. From this drive room the fuel enters the through an inlet valve Delivery chamber of a respective cylinder. Through the im Drive room fuel will be there moving parts are lubricated and cooled.

The object of the present invention is a Fuel system of the type mentioned above to train that the lubrication and cooling of the moving parts in the drive room under all Operating conditions is guaranteed.

This task is the beginning of a fuel system mentioned type in that the lubricant supply device the drive room with a pressure can be applied, which is higher than the pressure in the Low pressure area.

Advantages of the invention

In the fuel system according to the invention Lubrication and cooling of the moving parts of the high pressure fuel pump guaranteed even if in Low pressure area only a comparatively low pressure prevails. This is, for example, with such a fuel system possible, which is a low pressure fuel supply which provides a variable form. The background to this is the fuel savings through a reduction in drive power in the Low pressure fuel supply used Fuel pump.

Without the measures according to the invention there would be one such a fuel system there is a risk that, for example, in the Bearing area of the drive shaft of the high pressure fuel pump at a low fuel pressure in Drive room due to a local temperature increase steam formation in the drive room Fuel could come, which in turn is an impermissible Wear on the corresponding moving parts of the High-pressure fuel pump. This is through the measures according to the invention reliably avoided.

Advantageous developments of the invention are in Subclaims specified.

First, it is proposed that the drive room is fluidically closed to the low pressure area. As a result, a small amount of fuel is sufficient is to be supplied to the drive room in order to achieve the To cause pressure increase in the drive room. This increases the Efficiency of the fuel system.

It is also proposed that the lubricant supply facility a leakage gap from the delivery room to the drive room. The pressurization of the Drive room is in this way without complicated additional measures possible, which the manufacturing costs of keeps fuel system according to the invention low.

In concrete terms, it is again proposed that the leakage gap between the conveyor element and the housing is arranged. This also automatically Slide bearing lubricated between the conveyor element and the housing and chilled.

It is also possible that the fuel system High pressure area includes a pressure control valve, and that the lubricant supply device one Flow path, which includes the drive space with a Outlet of the pressure control valve connects. To protect the im High pressure area existing components and Pressure setting is usually on there Pressure control valve available. According to the invention Pressure control fluid for the pressure control valve Pressurization of the drive compartment used. So is with very simple means and without complex and expensive additional devices pressurizing the Drive room ensured.

It is also suggested that the fuel system be a Volume control valve with which a high-pressure side of the High pressure fuel pump with the Low pressure area can be connected, and that the Lubricant supply device a flow path comprising the drive chamber with an outlet of the Quantity control valve connects.

Such a volume control valve becomes speed-independent setting of the delivery rate of the High pressure fuel pump used. This is in all of those Cases where the high pressure fuel pump from the crankshaft or camshaft of an internal combustion engine is driven. When the volume control valve opens, high pressure fuel flows from the High pressure side off and thus does not reach, for example Fuel collecting line. This is according to the invention for the Lubrication and cooling of those in the drive room Components of the high pressure fuel pump exploited, so that a complex separate pressure supply for the Drive room can be omitted. Also through this training costs are thus saved.

In a further proposed training of Fuel system according to the invention comprises the Lubricant supply device a flow path, which is the drive room with the low pressure area can connect, and is in this flow path Check valve available, which to the low pressure area locks out. In this way, the drive room can also with a - albeit comparatively low - pressure be applied when the lubricant supply device the in itself in normal operation cannot provide the required high pressure yet.

This is the case, for example, when the high-pressure fuel pump driven by the internal combustion engine and if the low pressure fuel supply is a has electrically driven fuel pump. In this Fall can occur even before starting the engine by switching on the electric fuel pump certain pressure generated in the drive room and there any gas bubbles present are reduced or be eliminated.

Due to a very high pressure in the drive room can lead to an undesirable burden, for example Sealing devices of the high pressure fuel pump come. Around To avoid this, the invention also proposes that the fuel system is a pressure relief valve which includes the pressure in the drive compartment on a desired differential pressure limited.

Alternatively, it is possible that the fuel system comprises a pressure control valve, which the pressure in Drive room adjusts to a desired pressure. This has the advantage over a pressure relief valve that the maximum pressure in the drive compartment is lower.

In further training of the two alternatives mentioned above it is suggested that the outlet side of the Pressure relief valve and / or the pressure control valve with the low pressure fuel supply is connected. in the In the first case, a pressure is set in the drive room that is a certain differential pressure higher than that in Low pressure range existing fuel pressure (this. mostly corresponds to the pre-delivery pressure of an electrical one Fuel pump). Such a pressure relief valve builds simple and inexpensive. At high feed pressure, it can however, to an undesirably high pressure in the drive compartment come. This is prevented if instead of Pressure relief valve used the pressure control valve and if this is with the low pressure fuel supply connected is. In this case, the Pressure in the drive room in the low pressure area prevailing pressure.

The invention further relates to a fuel system for a Internal combustion engine, with a high pressure area and one High pressure fuel pump, which is a housing and comprises at least one movable conveyor element, wherein between at least two movable relative to each other Parts of the high pressure fuel pump are hydrostatic Storage is available.

The operational safety of the fuel system is then significantly improved when the hydrostatic bearing on the outlet of a pressure control valve is connected, which is located in the high pressure area. Through the hydrostatic bearings are relative between the two forces present in relation to one another moving parts considerably reduced. This lowers wear and tear for those High pressure fuel pump drive required Power.

The connection of the hydrostatic bearing to the Pressure control valve of the high pressure range enables in all Operating situations of the high pressure fuel pump Build up sufficient pressure in the hydrostatic Storage through which the formation of vapor bubbles avoided and the lubrication and cooling at this point is guaranteed, regardless of the actual High pressure fuel pump inlet pressure.

drawing

Figur 1

eine schematische Darstellung eines ersten Ausführungsbeispiels eines Kraftstoffsystems mit einer Hochdruck-Kraftstoffpumpe;

Figur 2

einen teilweisen Schnitt durch die Hochdruck-Kraftstoffpumpe von Figur 1;

Figur 3

einen teilweisen Schnitt durch einen Druckregler, welcher bei der Hochdruck-Kraftstoffpumpe von Figur 2 eingesetzt werden kann;

Figur 4

eine Darstellung ähnlich Figur 1 eines zweiten Ausführungsbeispiels eines Kraftstoffsystems;

Figur.5

eine Darstellung ähnlich Figur 1 eines dritten Ausführungsbeispiels eines Kraftstoffsystems; und

Figur 6

eine Darstellung ähnlich Figur 2 der HochdruckKraftstoffpumpe von Figur 4.

Particularly preferred exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawing. The drawing shows:

Figure 1

a schematic representation of a first embodiment of a fuel system with a high pressure fuel pump;

Figure 2

a partial section through the high pressure fuel pump of Figure 1;

Figure 3

a partial section through a pressure regulator, which can be used in the high pressure fuel pump of Figure 2;

Figure 4

a representation similar to Figure 1 of a second embodiment of a fuel system;

Figur.5

a representation similar to Figure 1 of a third embodiment of a fuel system; and

Figure 6

a representation similar to Figure 2 of the high pressure fuel pump of Figure 4.

Description of the embodiments

A fuel system has the reference number 10 in FIG. 1. It comprises a tank 12, from which an electrical one Fuel pump 14 delivers fuel. The fuel passes from the electric fuel pump 14 via a Filter 16 into a low pressure fuel line 18. From this branches off a branch line 20 in the one Low pressure fuel regulator 22 is arranged. The Branch line 20 leads back to tank 12.

The low-pressure fuel line 18 leads to a three-cylinder radial piston pump, which as a high pressure fuel pump 24 is referred to. A high pressure fuel line 26 leads from the high pressure fuel pump 24 to a fuel rail 28 ( "Rail"). There are several on the fuel rail 28 Injectors 30 connected, the fuel directly in in combustion chambers (not shown in FIG. 1) Inject internal combustion engine. The pressure in the Fuel rail 28 is from one Pressure control valve 32 set. This is about one Return line 34 with the low-pressure fuel line 18 connected.

A pressure sensor 35 detects that in the fuel rail 28 prevailing pressure and transmitted corresponding signals to a not shown in Figure 1 Control and regulating device. This controls depending on The electric fuel pump 14 needs fuel Pressure control valve 32, injectors 30, and others Facilities of the fuel system 10.

The high-pressure fuel pump 24 is shown in detail in FIG shown. In the cutting plane shown is however only one cylinder of the high pressure fuel pump 24 visible. In a radially stepped Blind bore 36 in a housing 38 are a cylinder head 40 and a cylinder liner 42 fitted. In the A piston 44 is slidably guided in the cylinder liner 42. Between piston 44 and cylinder liner 42 is a Leakage gap 45 is present. With its radially inner end the piston 44 is supported on a slide shoe 46. Piston 44 and slide shoe 46 are supported by a compression spring 48 against a contact surface (without reference number) a cam ring 50 pressed.

The cam ring 50 is seated on an eccentric section 52 Drive shaft 54. This is via two shaft bearings 56 and 58 rotatably supported in the housing 38. The drive shaft 54 is located axially in the housing 38 Blind bore 60. Between the housing 38 and the blind bore 60 on the one hand and the drive shaft 54, the cam ring 50, the Slide shoe 46, the piston 44 and the cylinder sleeve 42nd on the other hand, a drive room 62 is formed. This is sealed to the outside by a shaft seal 64.

Between the cylinder head 40, the cylinder liner 42 and the Piston 44 has a delivery chamber 66. This is over an inlet duct 68 and an existing in the housing 38 Inlet check valve 70 with the low pressure fuel line 18 connectable. The funding room is also 66 via an outlet channel 72 and an outlet check valve 74 with the high-pressure fuel line 26 connectable. Upstream of inlet check valve 70 an auxiliary duct 76 branches off from the inlet duct 68, which via a check valve 78 blocking the inlet duct 68 opens into the drive space 72. Branches from the auxiliary channel 76 another overflow channel 80, which over a Pressure relief valve 82 also in the drive chamber 62 empties.

Sobald die elektrische Kraftstoffpumpe 14 in Betrieb genommen wird, wird über die Niederdruck-Kraftstoffleitung 18 im Einlasskanal 68 ein Druck aufgebaut. Dieser wird über den Hilfskanal 76 und das Rückschlagventil 78 zu diesem Zeitpunkt (die Hochdruck-Kraftstoffpumpe 24 fördert noch nicht) in den Antriebsraum 62 übertragen. In diesem ist somit unter einem gewissen Druck (Vorförderdruck) stehender Kraftstoff vorhanden, der bei dem nun einsetzenden Betrieb der Hochdruck-Kraftstoffpumpe deren im Antriebsraum 62 befindliche bewegliche Teile schmiert. Hierzu gehören insbesondere das Lager 58, der Hubring 50 und der Gleitschuh 46.

The fuel system 10 shown in FIG. 1 and the high-pressure fuel pump 24 shown in FIG. 2 operate as follows:

As soon as the electric fuel pump 14 is put into operation, a pressure is built up in the inlet duct 68 via the low-pressure fuel line 18. At this time (the high-pressure fuel pump 24 is not yet delivering), this is transferred into the drive chamber 62 via the auxiliary channel 76 and the check valve 78. Fuel is therefore present in this under a certain pressure (pre-delivery pressure), which lubricates the moving parts located in the drive chamber 62 when the high-pressure fuel pump begins to operate. These include in particular the bearing 58, the cam ring 50 and the slide shoe 46.

By connecting the drive chamber 62 with the Low pressure fuel line 18 via the check valve 78 is a rapid loading of the drive space 62 with pressure, for example during initial commissioning or in the Possible case in which the hot Internal combustion engine in the drive room 62 a larger one Vapor bubble has formed. The pressure in the drive room 62 then corresponds to the form minus a small one Pressure drop of approximately 0.2 bar at check valve 78.

The high pressure fuel pump 24 is turned the drive shaft 54 put into operation. Usually is the drive shaft 54 from a crankshaft or from driven by a camshaft of the internal combustion engine, which supplies fuel from the fuel system 10 becomes. By rotating the drive shaft 54 Piston 44 reciprocated. At a radially inward suction stroke of the piston 44 Fuel via intake passage 68 and the intake valve 70 sucked into the delivery chamber 66. With one radially outward delivery stroke of the piston 44 closes the Inlet valve 70 and that enclosed in the delivery chamber 66 Fuel is compressed.

As soon as the differential opening pressure of the exhaust valve 74 is exceeded, the outlet valve 74 and opens compressed fuel can from the delivery chamber 66 in the High pressure fuel line 26 and on into the Fuel manifold 28 escape. A backflow of the compressed fuel from the fuel rail 28. into the delivery chamber 66 through the outlet valve 74 prevented. The fuel thus remains in the fuel line 28 stored under high pressure and can retrieved there by the injectors 30 and into the combustion chambers the internal combustion engine is injected under high pressure become.

If the fuel in a delivery stroke of the piston 44 in Delivery space 66 is compressed, also becomes a small one Amount of fuel through the leakage gap 45 between the Piston 44 and cylinder liner 42 from the delivery chamber 66 in the drive chamber 62 pressed. This will make the Drive chamber 62 fuel even more under Pressure put. As the check valve 78 to the intake port 68 blocks, no fuel from the drive compartment 62 escape. This will pressurize the Drive space 62 to a pressure level, which above the pressure level in the low pressure fuel line 18 lies. The normal operating pressure in Drive chamber 62 corresponds to the pressure in the low-pressure fuel line 18 plus the differential opening pressure of the pressure relief valve 82. By that Pressure relief valve 82 is considered an excessive increase of the fuel pressure prevailing in the drive chamber 62 prevented.

Usually the fuel pressure is that of the electric fuel pump 14 can be provided approximately 1 to 6 bar. At a differential pressure of Pressure relief valve 82 of approximately 2 bar results thus a pressure in the drive chamber 62 of approximately 3 to 8 Bar.

It is easy to see that the one prevailing in the drive space 62 Fuel pressure is in any case higher than that of the electric fuel pump 14 in the low pressure fuel line 18 and generated in the inlet channel 68 Form. In this way, in normal operation, if the electric fuel pump 14 only with lower Power is operated and the pressure in the low pressure fuel line 18 is comparatively low, so sufficient pressure in the drive chamber 62 ensures that even with relatively warm components in the drive compartment 62 Evaporation of the fuel and therefore a breakdown lubrication on the one hand and cooling on the other this point is prevented.

Because of the high pressure fuel pump 24 shown in Figure 2 is shown Pressure relief valve 82 between the drive chamber 62 and the pressure in the drive chamber 62 depends on the inlet duct 68 ultimately to a significant extent from that in inlet duct 68 prevailing form. Is this form, for example at a hot start of the internal combustion engine is relatively high the pressure in the drive chamber 62 is also comparatively high. It may be higher than to avoid one Vapor formation in the drive space 62 would be required per se. Such a high pressure, however especially the shaft seal 64 unnecessarily stressed what could reduce their lifespan. Therefore, in place of the pressure relief valve 82 shown in FIG. 2 a pressure control valve can also be used.

Such is shown by way of example in FIG. 3 and bears reference number 84 there. It comprises one of one Spring 86 acts upon diaphragm 88, which is supported by spring 86 is struck against a seat 90. The seat is 90 ring-shaped and separates one radially inside and connected to the inlet duct 68 Area from a radially outer and with the Drive space 62 connected area. The drive room 62 and the inlet duct 68 are only symbolic in FIG. 3 shown. A vent line (without reference number) is also shown.

When using the pressure control valve shown in Figure 3 84 is affected by a change in the intake duct 68 prevailing form only weakened to the pressure in the Drive space 62 out. The influencing factor can be about the choice of the pressurized areas can be determined.

In Figure 4 is a second embodiment of a Fuel system 10 shown. With this wear Components, area, and parts, which are equivalent Functions for components, areas, and parts of the in Figure 1 have fuel system shown same reference numerals and are not again in detail explained.

The high-pressure fuel pump 24 used in FIG. 4 is shown in detail in Figure 6 and will be further below explained in more detail. An essential difference of that in figure 4 shown fuel system 10 to that of Figure 1 concerns the type of pressurization of the Drive space 62 existing fuel. While at the used in Figure 1 high pressure fuel pump this Pressurization only through the leakage gap between Piston and cylinder liner takes place, is in the in Figure 4 illustrated embodiment additionally the Discharge fuel of the pressure control valve 32 used with which is the pressure in the fuel rail 28 is set. For this purpose leads from the Return line 34 a branch line 92 to the drive room 62nd

In Figure 5 is yet another embodiment a fuel system 10 shown. Wear with him too such components, areas, and parts which are equivalent Functions for components, areas, and parts of the in Figure 1 or the embodiment shown in Figure 4 have the same reference numerals. you are not explained again in detail.

A major difference from that shown in Figure 5 Fuel system 10 to that of Figure 4 relates to the High-pressure fuel pump 24. This is therefore shown in FIG. 5 also shown in somewhat more detail. So the delivery rate the high pressure fuel pump 24 regardless of the Speed of the drive shaft 54 can be adjusted in the high pressure fuel pump shown in Figure 5 24, a quantity control valve 94 is provided. This deals it is a magnetically operated 2/2 switching valve, its inlet with an area upstream from Exhaust valve 74, and its outlet with an area is connected upstream of the inlet valve 70.

The quantity control valve 94 can be used for a specific one Period opened during a delivery stroke of the piston 44 so that during this opening period the Fuel not into the fuel rail 28, but with correspondingly high pressure back into the Low pressure fuel line 18 is promoted. How out FIG. 5 shows a branch line 92 provided which from the outlet side of the Quantity control valve 94 leads to the drive chamber 62 and this thus pressurized.

For the sake of simplicity, this is the one in the present drawing Arrangement of the volume control valve shown as it is the case with a single cylinder pump. At a Multi-cylinder pump would have the input of the Open the volume control valve after the outlet valve. Based on this total point, one would then have to another check valve to the fuel manifold to be available.

A high pressure fuel pump 24 as shown in the figure 4 illustrated embodiment of a fuel system 10 can be used, is in Figure 6 in detail shown. The representation there corresponds to in essential points of the high pressure fuel pump from Figure 2. Therefore, such components, areas, and Parts that are equivalent functions to components, Areas, and parts of that shown in Figure 2 High pressure fuel pump have the same Reference numerals and are not explained again in detail.

In the high pressure fuel pump shown in Figure 6 24 the conveying space 66 is filled by a Inlet channel 68, which in the longitudinal direction in the piston 44th runs. The inlet check valve 70 is also in the Piston 44 arranged. Furthermore, the drive space 62 is over a duct 76 directly to the low pressure fuel line 18 connected. An auxiliary channel 96 leads from the Return line and the branch line 92 of the Pressure control valve also in the drive room 62nd

A pressure relief valve 82 is located in the auxiliary channel 96 arranged. From an upstream from Pressure relief valve 82 located area of the auxiliary channel 96 branches off a channel 98, which in one between the axial end of the drive shaft 54 and the housing 38 located room (without reference number) opens. In the Drive shaft 54 itself is one of the axial end surface outgoing and up to the eccentric section 52 in Channel extending in the longitudinal direction in the drive shaft 54 100 available.

This opens out to the longitudinal axis of the drive shaft 54 radially extending branch channels in the lateral surface of the Drive shaft 54, on the one hand in the area of the bearing 58 and on the other hand in the area of the eccentric section 52 or the cam ring 50. Since the pressure upstream of Pressure relief valve 82 in the auxiliary channel 96 comparatively is high (it is after all by the control fluid of the Pressure relief valve 32) is provided via the Channels 98 and 100 provide good lubrication of the bearing points the outer surface of the drive shaft 54 guaranteed.

As can be seen from Figure 6, the radial open Stub channels in lubrication pockets, which are in the outer surface the drive shaft 54 are present. The angular position of the Lubrication pockets in the area of the shaft bearing 58 is diametrical opposite to the angular position of the lubrication pocket in the area of the eccentric section 52. To avoid an axial force on the drive shaft 54, the channel 98 can also in the Casing surface of the drive shaft 54 open and over a Annular groove connected to the channel 100 in the drive shaft 54 his.

The fact that in the high-pressure fuel pump shown in Figure 6 24 the drive chamber 62 with the branch line 92 of the return line from the pressure control valve is connected (see FIG. 4), can on a check valve between Drive chamber 62 and low pressure fuel line 18 to be dispensed with. Still, a quick one Actuation of that located in the drive room 62 Fuel is ensured and at the same time also for intensive flushing in the drive compartment 62 is ensured. The same effect is achieved if the branch line 92 with is connected to the outlet of the volume control valve (cf. Figure 5).

Claims (11)

Fuel system (10) for an internal combustion engine, having a low-pressure region (18), a high-pressure fuel pump (24), and a high-pressure region (26, 28), the high-pressure fuel pump (24) comprising: a housing (38, 42), at least one movable conveying element (44) which delimits a conveying space (66), at least one drive (54) which can set the conveying element (44) in motion, a drive space (62) in which the drive (54) is at least partially arranged and a lubricant supply device (45; 92, 96) for supplying moving parts with fuel as lubricant, characterized in that the drive chamber (62) can be pressurized by the lubricant supply device (45; 92, 96) , which is higher than the pressure in the low pressure region (18). Fuel system (10) according to claim 1, characterized in that the drive chamber (62) is fluidically closed to the low pressure region (18). Fuel system (10) according to one of the preceding claims, characterized in that the lubricant supply device comprises a leakage gap (45) from the delivery chamber (66) to the drive chamber (62). Fuel system (10) according to Claim 3, characterized in that the leakage gap (45) is arranged between the delivery element (44) and the housing (42). Fuel system (10) according to one of the preceding claims, characterized in that a pressure control valve (32) is arranged in the high-pressure region (26, 28), and in that the lubricant supply device comprises a flow path (92) which shares the drive space (62) connects an outlet of the pressure control valve (32). Fuel system (10) according to one of the preceding claims, characterized in that it comprises a quantity control valve (94) with which a high-pressure side of the high-pressure fuel pump (24) can be temporarily connected to the low-pressure region (18), and that the lubricant supply device comprises a flow path (92) which connects the drive chamber (62) to an outlet of the quantity control valve (94). Fuel system (10) according to one of the preceding claims, characterized in that there is a flow path (76) which can connect the drive space (62) to the low-pressure region (18), and in that flow path (76) a check valve (78) is present, which blocks to the low pressure area (18). Fuel system (10) according to one of the preceding claims, characterized in that it comprises a pressure limiting valve (82) which limits the pressure in the drive chamber (62) to a desired differential pressure. Fuel system (10) according to one of the preceding claims, characterized in that it comprises a pressure control valve (84) through which the pressure in the drive chamber (62) can be set to a desired pressure. Fuel system (10) according to one of claims 8 or 9, characterized in that the outlet side of the pressure relief valve (82) and / or the pressure control valve (84) are / is connected to the low pressure region (18). Fuel system (10) for an internal combustion engine, with a high-pressure area (26) and a high-pressure fuel pump (24), which comprises a housing (38, 42) and at least one movable delivery element (44), with at least two parts ( 50, 52, 54, 58) of the high-pressure fuel pump (24), there is a hydrostatic bearing, characterized in that the hydrostatic bearing is connected to the outlet of a pressure control valve (32) which is arranged in the high-pressure region (28).

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