DE10136925C1 - Fuel injector for internal combustion engine with high-pressure piston pump and valves has pump working area linked on intake to low-pressure source and on compression to high-pressure reservoir - Google Patents

Abstract

A valve unit forms a valve module (4) covering a pump casing (3) on its head side and mounted on a flange against the pump casing. The valve module with seats for valve members like a return-stroke piston and an inhibiting piston acts as a support for a flange-mounted reservoir module (5) with a high-pressure reservoir. The reservoir module has a low-pressure channel leading to a source of low pressure and is attached on the valve module opposite the pump casing.

Description

The invention relates to a fuel injection device for Internal combustion engines according to the preamble of claim 1.

A prior art fuel injector of the aforementioned ten Art is known from WO 97/17538 A1 and works with egg ner high pressure pump, which is designed as a stamp pump, at Feeding the fuel in a suction cycle via a low pressure source and with promotion in compression stroke to a high accumulator. The connection of the stamp pump to the Nieder pressure source or the high-pressure accumulator takes place via a Ven tileinheit, which consists of two valve members, one in the Suction cycle the connection between high pressure storage and never the pressure source and the pump workspace and as a return percussion piston is formed and the other as a locking piston the connection of the pump workspace to the low pressure source in Compression stroke interrupts. The two valve members of the Ven tileinheit are coaxial to each other and are on their respective ge locking position spring-loaded, the locking piston over the Check piston guided and supported resiliently against this is such that the direction of action of the check piston loading spring and the spring loading the locking piston is equal to.

Due to this construction, the non-return piston is the Ven valve unit in a valve inserted into the pump housing body guiding element, with both the check piston as also the blocking piston in the non-return piston together determine a sealing limit with the valve body. This leads to an overall tolerance sensitive and proportionate  elaborate structure, especially the valve body of its on the other hand opposite the pump housing via a connecting piece is fixed so that both the structure of the valve unit as their arrangement and fixation in the pump housing the con structural options for a simple and compact opening Construction of the fuel injector, especially down visually complicate the arrangement relative to the pump housing, especially since the high-pressure accumulator and the necessary connection due to working pressures of the order of 2000 bar are exposed to the highest stresses.

From the point of view of minimizing the installation space required it is with fuel injection devices from DE 694 17 846 T2 known for a roller-driven stamp pump whose Pump cylinder ver against the housing of the roller drive flanged headboard to assign that as a high pressure accumulator Labyrinth of interconnected, formed by bores Has chambers and, starting from the pump work room, to conclude this and a low pressure source at two Switched control valve attached to the head part. in the High-pressure transition from the pump workspace to the high pressure accumulator is a non-return valve, the one on the seat side the cover plate of the pump chamber that closes off the pump work space linder is assigned, braced against the headboard is and also channel sections of the led over the head part Channel paths to the control valve or to the low pressure source. With the outsourcing of the connection to the low pressure source lying control valve arises, in view of that Headboard itself, a simplification, but overall a complete xer structure, which also the adaptation to different spatial and design constraints.

From DE 26 49 287 A1 it is known to use a fuel Injection pumps, which are designed to be particularly small Direct injection of stratified injection quantities in gasoline engines should serve and because of the very low injection quantities on egg ne minimization of the harmful volume of the pump work space  is designed to train with a pump housing that in the Ü transition between cylinder bore on the housing and pressure has a valve unit in the suction and Pressure valve, each designed as a check valve, is are arranged. The valve unit covers the head part of the Pump housing provided, receiving the pump piston cylinder the bore and is against the pressure connector Contact surface of the pump housing perpendicular to the cylinder bore braced.

Furthermore, EP 0 990 792 A2 describes a fuel Injection device for internal combustion engines with storage pressure injection known in which the pump against the pressure ver housing directly or indirectly is tensioned and in which the respective cylinder bore in the housing of the pressure accumulator, or in one of the housing of the Accumulator continues to use so that a Part of the pump work space in the housing of the pressure accumulator or in the assignment assigned to it and that to the pump operator beitsraum leading and from this towards the pressure memory running, each secured via check valves connections run through the housing of the pressure accumulator. in the the total results for the housing of the pressure accumulator relatively complex structure, from which the corresponding con structural constraints follow.

The invention has for its object a fuel Injection device of the type mentioned with regard to form a simple, variable structure that is also egg ne simple design of the valve unit enables.

According to the invention this is with the features of the claim 1 reached.

Here, the valve unit as the pump housing is on the head side overlapping valve flanged against the pump housing designed module, which in turn supports for a flanged,  the high-pressure accumulator comprehensive storage module. Such a modular structure enables the configuration the valve unit both in terms of a space-saving as also a technically manageable arrangement where at the same time the requirements are met via the valve unit for the connection to the high-pressure accumulator or the high pressure accumulator and the connection to the low pressure to design the source or the low pressure source modularly and with the valve module to a spatially closed, in view unit to be modified to suit the respective installation conditions connect.

As part of the modular design of the valve unit and the connection to the high pressure accumulator or before moves the high pressure accumulator itself and the connection to the never derdruckquelle, or in particular the connection to, the never derdruckquelle including the low pressure source can in Within the scope of the invention, the connections or the high-pressure accumulator with the connections to the low pressure source and also the low pressure source can be summarized in one module, whereby for the three connection sides of the valve module are available stand. It is also within the scope of the invention, a modu lary division into a storage module and a low pressure module to be carried out, these modules being separate from one another sides of the valve module or also one above the other can be assigned to the following pages of the valve module. here it is also within the scope of the invention to cross the modules did not cut rectangular, but in another cross to form a sectional shape with flat connection sides, so at for example triangular, so that nested structure ren result that the adaptation to various in a favorable manner enable the most diverse of spaces, without the Structure of the individual module would be complicated, and this also regarding the valve module.

The flat system of storage module and / or low pressure module With regard to the valve module, the valve module offers the possibility of  the valve members in the form of the locking piston and the back percussion piston starting from the stop surface hen, so that there are simple bore guides, ei ne particularly simple solution is to use a through working bore in which the respective valve member is based on the connection area opposite the memory module and the valve module Low pressure module.

With regard to such a structure, it proves to be particularly useful as appropriate, both the locking piston and the kickback then piston to the distribution space that is in the common Connection to the pump work room, each with a to provide a guide section sealing against the bore and preferably with a central, starting from the distribution room Bore forming a channel section in the transition from the pumpar working room on the high pressure accumulator or the low pressure source forms, this channel section via cross holes on egg NEN annulus opens out by one opposite the leader section of reduced diameter section of the recoil piston or the locking piston is formed, on which the sealing limit of the respective piston element to the guide bore follows. Especially in connection with such a training It proves one, in particular both valve members as expedient, bridging the distribution space which the ratchet ben in the direction of its closed position loading spring hen. For the locking piston has been shown in the Training an embodiment as appropriate, in which the ring space against which the end face associated with the sealing limit is open, so that the diameter range reduced by the annular space the end face can serve as part of the sealing limit over which the locking piston prefers against the adjacent low pressure mo dul is supported so that the contact surface of the low pressure mo duls forms part of the sealing limit.

Further details and features of the invention emerge from the claims. The invention is further illustrated below  of exemplary embodiments with further details he purifies. Show it:

Fig. 1 is a perspective, schematic representation of a high-pressure stamp pump for internal combustion engines, in which the associated punch pump head side covers to the pump chamber of a valve module of the fuel injection device, a memory module and, opposite, a low are print module provided on the side then,

Fig. 2 is a schematic sectional view through the head portion of the punch pump with covering valve module and laterally flange-mounted on this memory module and low-pressure module,

Fig. 3 is a FIG. 2 corresponding representation in the other form the valve members of the valve modules,

Fig. 4 is an enlarged sectional view of the Ventilglie that of the valve module of FIG. 3, and

. 5 shows a further embodiment of the assignment of the SpeI to the valve module, wherein the low-pressure side connections or possibly also the low-pressure source are integrated FIG chermoduls in the memory module.

Fig. 1 shows a view of a high-pressure pump 1 , which is designed as a stamp pump and, flanged against an internal combustion engine not shown, is to be driven via this. The flange and drive connection is indicated at 2. The Pum pengehäuse is designated 3 and covered on the head side by a valve module 4 , against which a storage module 5 and a low-pressure module 6 are flanged. Memory module 5 and low-pressure module 6 are, transversely to the longitudinal extension of the multi-cylinder plunger pump shown, assigned to opposite longitudinal sides of the valve module 4 , with a flat system being provided between the modules, as the examples according to FIGS . 2, 3 and 5 illustrate ,

. The sectional views according to Figures 2, 3 and 5 move from a configuration of the pump housing 3, are eingebüchst in the pump cylinder 7 in a jacket 8, wherein the pump cylinder 7 form guides for pump plunger 9, which - when not Pictured drive, for example a Cam or Rol lenantrieb for the pump plunger 9 - these delimit a working space 10 on the head side relative to the pump cylinder 7 , from which a connection bore 12 leading to the head end 11 of the pump housing 2 extends.

The end face 11 is covered by a valve module 4 , which, as indicated at 14 ( FIG. 3), is flanged against the end face 11 of the pump housing 3 and has the valve-controlled connections to a storage module 5 and a low-pressure module 6 .

When valve members 2, a check piston 17 and a locking piston 18 are shown in FIG. Provided, of which the non-return piston 17 9, the connection between the memory module 5 associated high-pressure accumulator 19 penarbeitsraum in the suction stroke of the pump plunger towards the pump 10 and controls the low-pressure module 6 during the compression stroke over the locking piston 18 the connection between the pump's work space 10 and low pressure module 6 is interrupted.

The low-pressure module 6 is illustrated with a storage space 21 on the low-pressure side formed by a bore, wherein a corresponding low-pressure pump sucking from a sump can also be integrated in the module 6 , for example as a tube pump.

From the high-pressure accumulator 19 , in a known manner, which is not shown, there are connecting bores to injection injectors of internal combustion engines.

The connection bore 12 assigned to the pump cylinder 7 goes to the valve module 4 via an overlapping connection bore 22 , which opens out onto a transverse bore 25 leading between the mutually opposite, lateral connection surfaces 23 , 24 of the valve module 4 for the storage module 5 and the low pressure module 6 .

This transverse bore 25 forms a distribution space, in the transition to the high-pressure accumulator 19 or the low-pressure storage space 21 of the check piston 17 or the locking piston ben 18 .

The check piston 17 and the locking piston 18 are each arranged in outgoing from the connecting surfaces 23 and 24 , expanded in diameter to the transverse bore 25 , the check piston 17 against the part formed by the connection area of the transverse bore 25 to the connecting bore 22 with its sealing cone 26 forms a sealing limit and is loaded in the direction of this sealing limit via a spring 27 . The spring 27 is located in a cup-like extension in remote from the sealing cone end of the check piston 17 and is supported against the flanged memory module. 5

If the pump plunger 9 is in the compression or delivery cycle, the check piston 17 is moved against the force of the spring 27 from its locked position in the direction of the storage module 5 , as a result of which the sealing cone 26 transfers to a downstream annular space and one to which Spring 27 aufneh mende cup opening bore connection releases, so that the working medium is fed into the high pressure accumulator 19 . The locking piston 18 in the transition from the ge through the transverse bore 25 distribution space on the low-pressure side storage space 21 or low-pressure side connections is in its structure, except for the arrangement of the spring, largely the locking piston 28 accordingly, as he with reference to FIGS . 3 and 4 is explained, so that reference is made to the relevant statements.

In the embodiments according to FIGS. 3 and 4 is the overall structure according to Fig. Given 2 corresponding structure, wherein Lich of the valve module 4 bezüg with a locking piston 28 and a check piston is worked 29 as of in Fig. 4 in their arrangement within Valve module 4 are shown in their assignment to the storage module 5 and the low pressure module 6 .

In the embodiment according to FIGS. 3 and 4, locking piston 28 and check piston 29 with the same guide diameter in egg ner between the memory module 5 and the low-pressure module 6 extend the transverse bore 25 is arranged, the connection bore in the transition to the On 22 forms the distribution chamber, to which adjacent the locking piston 28 and the check piston 29 have in the transverse bore 25 sealingly guided guide section 30 and 31 respectively. Between these guide sections 30 and 31 lies, bridging the distribution brown, the spring 32 loading the locking piston 28 onto its closed position. The guide section 30 is provided with a central channel bore 33 , which opens out via a transverse bore 34 into an annular space 35 , which is formed by a diameter reduction on the part of the locking piston 28 and which is open at the end in the direction of the low-pressure module 6 , so that there is connection with a central end-side recess 36 of the locking piston 28 an annular sealing boundary 37 in the system against the connection surface of the never derdruckmodules 6 results. The opposite Rückschlagkol ben 29 also has, following its guide section 31, a reduced-diameter area, so that an annular space 38 results, onto which a central channel bore 39 extending from the distribution space opens out via transverse bores 40 and that in the direction of the memory module 5 into a section 41 enlarged in diameter compared to the guide section 31 , to which an enlarged bore area 42 is assigned, in such a way that a sealing limit 43 results in the transition to the respectively enlarged section or area.

In the closing direction of this sealing limit 43 , the non-return piston 29 is loaded via the spring 44 , which lies in a spring pocket 45 of the memory module 5 . A structure of a valve module 4 with such an arrangement of the valve members formed by locking pistons 28 and check pistons 29 leads in conjunction with the valve module 4 laterally opposed memory module 5 and low pressure module 6 to a particularly expedient and technically well producible unit.

Fig. 5 shows a further embodiment of the invention with modular units, with 46 a combination module is characterized, which includes the high-pressure accumulator 19 and the low-pressure storage chamber 21 , the Kombinationsmo module 46 opposite the pump housing 3 opposite the valve module 47 , the a valve module 47 with respect to its seats for the valve members, namely, butt the check 17 and the lock piston 18, analogously to FIG. 2 is formed in assignment of the recordings for the check piston 17 and the interlocking piston 18 to the combining module 46 supplied arrange th and covered by this connecting surface 48 , From one of the opposite end face of the valve module 47 zugeord Neten distribution chamber 49, which opens from the pump working chamber 10 from reaching the connection bore 12, lead connection channels 50 and 51 to return piston 17 and locking piston 18th

The locking piston 18 has both in the embodiment shown in FIG. 2 and in FIG. 5 a design corresponding in principle to the structure in FIG. 3, apart from the arrangement of the spring acting on the locking piston 18 , which in the design from FIG. 2 and 5 lies essentially in a spring cup projecting into the guide part of the locking piston 18 .

Analogous to a fork in the connecting channels 50 and 51 according to FIG. 5, for example in the case of a triangular design of the valve module, the valve members can also be arranged in accordance with the extension of the connecting channels and in alignment therewith, the corresponding connection surfaces then being perpendicular to the connecting channels, so that the same basic conditions are given with regard to the receptacles for the valve members as in the previously described exemplary embodiments.

Claims (19)

1.Fuel injection device for internal combustion engines with a high-pressure plunger pump in a pump housing, the pump work chamber of which is connected in the suction cycle to a low-pressure source and in the compression cycle to a high-pressure accumulator via a valve unit, which is arranged on the head side of the pump work chamber and is taken up by this, comprises two valve members, which are located in the connection path of the pump chamber to the low-pressure source or to the high-pressure accumulator and of which the one valve member is formed by a locking piston pressurized in the compression cycle in the closing direction, the pump working chamber delimiting the low-pressure source, and the other valve member than im Suction cycle from the high-pressure accumulator pressurized, the high-pressure accumulator against the low-pressure source and the pump work chamber blocking non-return piston is formed, both valve members being spring-loaded in the closing direction, thereby g ekennzeichnet that the valve unit and the pump housing (3) on the head side ü berdeckendes and verflanschtes against the pump housing (3) Ven tilmodul (4; 47 ), which in turn is a carrier for a flanged-on storage module ( 5 ; 46 ) comprising the high-pressure accumulator ( 19 ). 2. Fuel injection device according to claim 1, characterized in that the storage module ( 46 ) comprises a lead to the low pressure source, the low pressure channel ( Fig. 5). 3. Fuel injection device according to claim 1 or 2, characterized in that the storage module ( 46 ) opposite to the pump housing ( 3 ) on the valve module ( 47 ) is attached ( Fig. 5). 4. Fuel injection device according to claim 1 or 2, characterized in that the storage module ( 5 ) with respect to the longitudinal axis of the pump work chamber ( 10 ) is arranged laterally on the valve module ( 4 ) ( Fig. 2, 3). 5. Fuel injection device according to claim 1, characterized in that in addition to the storage module ( 5 ) a separate low pressure module ( 6 ) is attached to the valve module ( 4 ) ( Fig. 2, 3). 6. The fuel injection device according to claim 5, characterized in that the low-pressure module ( 6 ) comprises a low-pressure channel leading to the low-pressure source, in particular a low-pressure supply chamber. 7. Fuel injector according to one of the preceding the claims characterized, that the low pressure duct together with the low pressure source is assigned to the same module. 8. The fuel injector according to claim 7. characterized, that the low pressure source is arranged in the low pressure channel. 9. Fuel injection device according to one of claims 5 to 8, characterized in that the low pressure module ( 6 ) opposite to the storage module ( 5 ) on the valve module ( 4 ) is arranged ( Fig. 2, 3). 10. Fuel injection device according to one of claims 5 to 9, characterized in that in the case of a separate low-pressure module ( 6 ), the valve module ( 4 ) for the pump housing ( 3 ) and for the storage module ( 5 ) and / or for the low-pressure module ( 6 ) is a two-dimensional system has ( Fig. 2, 3). 11. Fuel injection device according to one of claims 1 to 4, 7 or 8, characterized in that the valve module ( 47 ) to the pump housing ( 3 ) and to the storage module ( 46 ) has a flat system ( Fig. 5). 12. Fuel injection device according to one of claims 5 to 9, characterized in that in the case of a separate low-pressure module ( 6 ), the valve module ( 4 ) starting from its respective side adjoining the storage module ( 5 ) and / or the low-pressure module ( 6 ) has a receptacle for the corresponding valve member (check piston 17 ; 29 ; locking piston 18 ; 28 ) ( Fig. 2, 3). 13. Fuel injection device according to one of claims 1 to 4, 7, 8 or 11, characterized in that the valve module ( 47 ) starting from its, to the SpeI chermodul ( 46 ) side members for the valve members (check piston 17 ; 29 ; locking piston 18 ; 28 ) ( Fig. 5). 14. Fuel injection device according to claim 12 or 13, characterized, that the inclusion as of that for the particular valve member outgoing through the subsequent module covered end face Location hole is formed.   15. Fuel injection device according to one of claims 12 to 14, characterized in that with each other to the valve module ( 4 ) opposite storage module ( 5 ) and low pressure module ( 6 ), the receptacles for the corresponding valve members (check piston 17 ; 29 ; locking piston 18 ; 28 ) are assigned to a common bore ( 25 ) which penetrates the valve module ( 4 ) (FIGS . 2, 3, 4). 16. Fuel injection device according to one of claims 12 to 15, characterized in that for the valve module ( 4 ) arranged, formed by a return piston ( 29 ) formed valve member in the closing direction loading spring ( 44 ) in the flanged memory module ( 5 ) is arranged ( Fig. 3, 4). 17. Fuel injection device according to claim 15 or 16, characterized in that in coaxial in the bore ( 25 ) lying valve members (check piston 29 ; locking piston 28 ) the locking piston ( 28 ) acting in the closing direction spring ( 32 ) against the return piston ( 29 ) is supported ( Fig. 3, 4). 18. Fuel injection device according to one of claims 15 to 17, characterized in that the locking piston ( 28 ) acting spring ( 32 ) in egg nem between the valve members (check piston 29 , locking piston ben 28 ) is arranged, the connection with the pump work space ( 10 ) ( Fig. 3, 4). 19. Fuel injection device according to claim 18, characterized in that, starting from the distribution space, the locking piston ( 28 ) and / or the non-return piston ( 29 ) with a channel section ( 33 or 39 ) running in the direction of displacement, in particular centrally, to the low-pressure module ( 6 ) or to the memory module ( 5 ) are / is, the sealing limit formed by the locking piston ( 28 ) or the return piston ( 29 ) to the low pressure module ( 6 ) or to the memory module ( 5 ) on one formed in the receiving bore Annulus ( 35 and 38 ) opens out ( Fig. 3, 4).