DE102009000830A1 - Fuel injector with length-adjustable coupler concept - Google Patents

Abstract

A fuel injector (10) for injecting fuel into a combustion chamber of an internal combustion engine is proposed. The fuel injector (10) comprises at least one actuator and at least one injection valve member (21) for closing or releasing at least one injection opening (52). The injection valve member (21) is hydraulically controlled by the actuator via at least one valve rod (22) and at least one hydraulic valve (48). The valve rod (22) is connected to the actuator via at least one hydraulic coupler (54) which comprises a coupler space (30) and a coupler sleeve (32). The coupler sleeve (32) is configured at least in two parts and comprises a sleeve part (64) at least partially enclosing the coupler space (30) and a spring support part (66). The spring support part (66) has at least one spring support (74) for acting on the coupler sleeve (32) with a spring force.

Description

State of the art

Out Many types of fuel injectors are known in the art for injecting fuel into the combustion chamber of an internal combustion engine known. The following description refers in particular on fuel injectors, which in the context of high-pressure accumulator injection systems are used to extract fuel from a high-pressure accumulator (Common Rail) inject into a combustion chamber of a self-igniting internal combustion engine. However, the invention is not limited to such applications and basically too for others Types of fuel injectors and / or other types of internal combustion engines used.

fuel injectors As a rule, have an injection valve member, which in a injector is movably mounted and which is adapted to one or several injection openings to close or release. Many fuel injectors are based on that the position of the injection valve member and thus the opening behavior the injection valve member hydraulically via at least one hydraulic Valve is controlled. By means of this hydraulic valve is a control chamber above the injection valve member, depending on the switching position, subjected to a high pressure or depressurized. In a depressurized State, the injection valve member in the direction of the control room move, the at least one injection port will be released, and the injection process begins.

The Hydraulic valve usually has at least one actuator on, which can be configured for example as a valve rod or which may comprise such a valve rod. This valve rod is controlled by an actuator, such as a magnetic actuator and / or a piezoelectric actuator, moves.

A technical challenge with such known fuel injectors However, in many cases the high installation space of known fuel injectors. In particular the high length of the Hydraulic modules known fuel injectors leads to many fuel injectors can not be used in all engine variants. In addition, are known Fuel injectors constructed comparatively complex and condition thus a complex and costly production.

Disclosure of the invention

It Therefore, a fuel injector for injecting fuel proposed in the combustion chamber of an internal combustion engine, which the disadvantages of known fuel injectors described above at least largely avoids.

Of the proposed fuel injector comprises at least one actuator, in particular a piezoelectric actuator and / or a magnetic actuator, and at least one injection valve member for closing or releasing at least one injection port. The injection valve member is hydraulically actuated by the actuator via at least a valve rod and at least one hydraulic valve controlled.

The Valve rod is over with the actuator connected to at least one hydraulic coupler, which a Coupling space and a coupler sleeve comprises. Here is the coupler sleeve multi-part, so at least two parts, designed and includes a sleeve part at least partially enclosing the coupler space and a spring support part. The spring support part has at least one spring support for applying the coupler sleeve with a spring force on.

Under a valve rod is a rod-shaped, so elongated, preferably to understand essentially straight formed element which basically may have any cross-section. For example, can the valve rod at least substantially substantially with a be configured round cross-section.

The Valve rod can be further components of the hydraulic valve include, for example, at least one seat, for example one or several valve plates. These other ingredients can with other components of the hydraulic valve, for example other seats, interact, to the hydraulic valve action, depending on the position of the valve stem, to accomplish. The valve rod can in particular with at least a guide be movably mounted.

Of the Hydraulic coupler is an element in which a force and / or stroke transmission between the at least one actuator and the valve rod via at least a hydraulic fluid is accomplished, preferably fuel. The hydraulic coupler can also be a pressure transmission ratio and / or have a Hubübersetzungsverhältnis, which basically can be arbitrary. Particularly preferred is a transmission ratio of 1: 1, but also deviations from this ratio tolerable are, preferably not more than 5%.

The hydraulic valve is preferably designed as a force-balanced hydraulic valve. This means that the hydraulic valve preferably opens force-free. This can be accomplished, for example, by the hydraulic valve is designed with oppositely acting, equal in terms of the same hydraulic surfaces, so that even with high pressure admission, the hydraulic valve or its actuator or the valve stem can move freely in both directions. In addition, at least one valve spring can be provided which holds the hydraulic valve in a specific closed position and whose spring force must be overcome by the actuator for switching.

The Spring support is formed by at least one surface on which at least a spring element may rest to the coupler sleeve with a spring force apply. For example, the spring support at least one encircling edge, for example a circumferential annular shoulder, on which a spring can rest.

The Spring support member can in particular with the sleeve part by a detachable connection be connected to each other, in particular a plug connection. For example it can be a manually detachable Act connection. Thus, the sleeve part, for example, in be inserted the spring rest part.

The Spring support member may, for example, at least partially a sleeve shape exhibit. In particular, the spring support part can at least partially cup-shaped be configured, wherein the valve rod extends through an opening in the Floor of the spring support member extends therethrough. The sleeve part can be inside the cup-shaped be formed trained spring rest part. The valve rod can then pass through the opening in the bottom of the Federauflageteils into the interior of the sleeve part extend.

Between the sleeve part and the spring support member may further at least one interchangeable Spacer be arranged. By this spacer, which For example, may include at least one shim may for example, a length adjustment and / or a length compensation a hydraulic module of the fuel injector.

To the Apply the coupler sleeve with the spring force can be provided at least one spring element, For example, a coil spring and / or a spring sleeve. This at least one spring element is at one end on the spring rest propped up. At its opposite end can the spring element on a further element of the fuel injector, in particular of the housing of the fuel injector, propped up be.

Especially can the spring element on a valve plate of the hydraulic valve to be supported So an element in which the hydraulic valve is fully or partially formed. In particular, the spring element directly supported on the valve plate be without, for example, a dial required would. A Setting the spring force of the spring element, for example through the above-described exchangeable spacer between Spring support part and sleeve part the coupler sleeve respectively.

The Spring element for acting on the coupler sleeve with a spring force can enclose the spring support part at least partially circumferentially. The Spring element can thus at least partially on the spring support part guided become.

Of the Hydraulic coupler can continue at least one the coupler space limiting setting piece exhibit. For example, this adjusting piece can be assigned to a the actuator Be arranged end of the coupler space. The adjusting piece can also be penetrated by at least one bore, over which the coupler space can be acted upon with hydraulic fluid. The adjusting piece limits the coupler gap, which forms the coupler space, in common with the coupler end of the valve stem. The adjusting piece can do this be performed at least partially in the Federauflageteil. For example, can in the field of this leadership the spring support member at least partially sleeve-shaped to be the adjusting piece too to lead.

As As shown above, the hydraulic valve may continue at least include a valve spring. This valve spring can be on the valve stem supported Be and be set up to close the valve stem with a closing force apply. For example, in the valve stem a circlip groove be provided, in which a retaining ring is inserted, on which in turn the valve spring may be supported.

Of the Fuel injector according to the invention in one or more of the embodiments described above points opposite known fuel injectors numerous advantages. That's the way it is now possible, the length of the entire fuel injector. Furthermore, since now an adjustment of a spring force, which acts on the coupler sleeve is, by other means (for example, by the said, exchangeable spacer element) possible is omitted, a different dial. So in many conventional fuel injectors For example, a dial at an upper end of the valve plate provided, which are embedded in a recess of the valve plate is.

By the now proposed preferred construction, this puncture eliminated, which simplifies the entire structure and costs save. The coupler sleeve can now be greatly simplified getting produced. In particular, an integrally formed directly on the coupler sleeve Omitted spring support and replaced by the multi-part construction of the coupler sleeve become. Also a leadership association for a adjusting piece may be omitted because, as shown above, the setting piece now guided in the Federauflageteil can be.

All in all let yourself continue the total length reduce the hydraulic module of the fuel injector. Thereby is a shortening the fuel injector, for example, by up to 4 mm possible. hereby turn, can be a larger number of Internal combustion engines with the proposed fuel injectors equip.

Brief description of the drawings

embodiments The invention is illustrated in the drawings and in the following Description closer explained.

It demonstrate

1 a known embodiment of a fuel injector; and

2 a modification of a hydraulic module of the fuel injector according to the invention 1 ,

embodiments

In 1 is a known embodiment of a fuel injector 10 shown. The fuel injector 10 includes an actuator module 14 , This takes, for example, a piezoelectric actuator or a solenoid valve, with which the fuel injector 10 is pressed.

Below the actuator module 14 as shown in 1 there is a hydraulic module 16 , For example, via a nozzle retaining nut 18 is a nozzle body in this embodiment 20 , in which an example of a needle-shaped injection valve member 21 is movably received, with the hydraulic module 16 connected.

The hydraulic module 16 includes a valve stem 22 , an optional valve plate 24 and one below the valve plate 24 in the hydraulic module 16 arranged optional throttle plate 26 , In the valve plate 24 and in the throttle plate 26 is a hydraulic valve 48 educated. The valve rod 22 acts as an actuator of this hydraulic valve 48 , The valve rod 22 is substantially parallel to an axis of symmetry 46 arranged and is parallel to this axis of symmetry 46 movably mounted.

From the illustration according to 1 it turns out that the valve stem 22 via a valve spring 38 in a closing direction is subjected to force. The valve spring 38 is at its lower end on the valve plate 24 supported. At its upper end is the valve spring 38 on a circlip 60 supported, which in a circlip groove 62 on the valve stem 22 is included.

At the valve stem 22 is located on the throttle plate 26 assigning end a valve plate 44 a in this example outwardly opening valve seat 42 , About the valve spring 38 is the valve plate 44 to the lower end of the valve plate 24 , the valve seat 42 closing, employed.

The valve plate 44 is in the closed state of the hydraulic valve 48 in the valve seat 42 pressed. This will become a control room 50 above the injection valve member 21 pressurized with fuel pressure, and the injection valve member 21 closes (in 1 not shown) injection ports. If, however, the valve stem 22 in 1 moved down, so opens the hydraulic valve 48 , the control room 50 is connected to a low-pressure part and depressurized, and the injection valve member 21 releases the injection openings.

1 is further evident that the fuel injector 10 a hydraulic coupler 54 having the actuator with the valve stem 22 coupled. Preferably, this hydraulic coupler has 54 a coupling ratio of 1: 1. The hydraulic coupler 54 includes a coupler space 30 in the form of a coupler gap 58 which is in a coupler sleeve 32 is executed. Above the coupler room 30 there is a setting piece 28 which partially into the upper end face of the coupler 32 is taken in and in a leadership 56 is guided.

The coupler sleeve 32 in turn relies on the in 1 illustrated embodiment via a spring element in the form of a spring sleeve 34 on top of the valve plate 24 from. Alternatively or in addition to the spring sleeve 34 can also be provided a coil spring, which in 1 with the reference number 36 is designated. Both in the alternative with spring sleeve 34 as well as the alternative with coil spring 36 can both components 34 respectively. 36 on one in the upper end face of the valve plate 24 taken in support ring 40 support. The support ring 40 can be designed as a dial and can in a recess in the valve plate 24 be included.

At the fuel injector 10 according to 1 and its hydraulic module 16 So is the coupler 32 on the valve stem 22 guided. At the same time the coupler sleeve is used 32 as a guide and stop for the spring sleeve 34 or the coil spring 36 , As a result, on the one hand, the necessary bias on the actuator module 14 applied as well as the coupler gap 58 sealed against the return.

Another task of the coupler sleeve 32 lies in the leadership of the setting piece 28 , This guide is needed to adjust the setting piece 28 during assembly of the hydraulic module 16 in the fuel injector 10 introduce.

In the valve plate 24 is in the in 1 illustrated embodiment of the support ring 40 embedded as a dial, by means of which the necessary spring force is set at a given length. This shim is in a recess in the valve plate 24 sunk. In the upper area is the setting piece 28 placed, with which the tolerances of the actuator module 14 can be compensated.

Disadvantageous in the 1 However, the construction shown is that of the fuel injector 10 is configured comparatively long. Because of this great length, not all engine types can handle this fuel injector 10 to be served. This may result in a competitive disadvantage.

In 2 In contrast, an inventive hydraulic module 16 a fuel injector according to the invention 10 shown. This hydraulic module 16 according to 2 For example, in the fuel injector 10 according to 1 be used. For more, in 2 not shown and not described below, therefore, for example, to the above description of 1 to get expelled.

The hydraulic module 16 in turn, analogous to the embodiment according to 1 , a valve rod 22 , which at their upper end in a coupler room 30 a hydraulic coupler 54 empties. The coupler room 30 will turn, analogous to 1 , closed at the top by the adjusting piece 28 and in turn is annularly enclosed by a coupler sleeve 32 ,

In contrast to the embodiment according to 1 is in the embodiment according to 2 the coupler sleeve 32 but not in one piece, but designed at least two parts and has a sleeve part 64 on which the coupler room 30 radially surrounds and which is annular, and a spring support member 66 , The spring support part 66 is cup-shaped in this embodiment and surrounds the sleeve part 64 periphery. The spring support part 66 has a floor 68 up, with an opening 70 through which the valve stem 22 inside the spring support part 66 entry. Between the ground 68 and the sleeve part 64 is a dial 72 brought in. This shim 72 acts as a spacer and can be used for length compensation.

The sleeve part 64 is in the spring pad part 66 preferably inserted accurately. Furthermore, in this spring support member at the upper end, above the sleeve part 64 , the adjusting piece 28 inserted, which the coupler space 30 limited to the top. The spring support part 66 So acts as a guide for the setting piece 28 ,

At its upper end comprises the Federauflageteil 66 a spring pad 74 in the form of a circumferential edge 76 , Between this spring pad 74 and the valve disc 24 extends in this embodiment, a spring sleeve 34 , which, however, analogous to 1 , also by a coil spring 36 can be replaced. This spring sleeve 34 encloses at its upper end the Federauflageteil 66 circumferentially and is thus on Federauflageteil 66 guided.

In contrast to the embodiment according to the prior art in 1 must be the spring sleeve 34 or the coil spring 36 not necessarily on a replaceable support ring at its lower end 40 be stored. Due to the two-part design of the coupler can now the spring support part 66 geometrically designed so that this both a bearing surface for the sleeve part 64 the coupler sleeve 32 offers as well as for the spring sleeve 34 ,

The spring force of the spring sleeve 34 or the coil spring 36 can now on the positioning of the spring support part 66 be set. The spring force of the spring sleeve 34 or the coil spring 36 can over the spring support part 66 and the sleeve part 64 the coupler sleeve 32 to the adjusting piece 28 be transmitted. The adjustment of the spring force according to the invention by the shim 72 between the spring support part 66 and the sleeve part 64 will be realized.

In this way, a total length can be saved in the construction of the fuel injector 10 realize. Depending on the design of the individual components further shortening of the fuel injector are conceivable.

Claims (11)

Fuel injector ( 10 ) for injecting fuel into a combustion chamber of an internal combustion engine, comprising at least one actuator and min at least one injection valve member ( 21 ) for closing or releasing at least one injection opening ( 52 ), wherein the injection valve member ( 21 ) from the actuator hydraulically via at least one valve rod ( 22 ) and at least one hydraulic valve ( 48 ) is controllable, wherein the valve rod ( 22 ) with the actuator via at least one hydraulic coupler ( 54 ), the hydraulic coupler ( 54 ) a coupler space ( 30 ) and a coupler sleeve ( 32 ), wherein the coupler sleeve ( 32 ) is configured at least in two parts and a the coupler space ( 30 ) at least partially enclosing sleeve part ( 64 ) and a spring support part ( 66 ), wherein the spring support part ( 66 ) at least one spring support ( 74 ) for applying the coupler sleeve ( 32 ) having a spring force. Fuel injector ( 10 ) according to the preceding claim, wherein the spring support part ( 66 ) the sleeve part ( 64 ) at least partially encloses. Fuel injector ( 10 ) according to the preceding claim, wherein the spring support part ( 66 ) at least partially has a sleeve shape. Fuel injector ( 10 ) according to one of the two preceding claims, wherein the spring support part ( 66 ) is at least partially cup-shaped, wherein the valve rod ( 23 ) through an opening ( 70 ) in the ground ( 68 ) of the spring support part ( 66 ) extends therethrough. Fuel injector ( 10 ) according to one of the preceding claims, wherein the sleeve part ( 64 ) and the spring support part ( 66 ) Are connected to each other by a detachable connection, in particular a plug connection. Fuel injector ( 10 ) according to one of the preceding claims, wherein between the sleeve part ( 64 ) and the spring support part ( 66 ) at least one exchangeable spacer element is arranged, in particular at least one adjusting disk ( 72 ). Fuel injector ( 10 ) according to one of the preceding claims, wherein the spring support ( 74 ) at least one peripheral edge ( 76 ). Fuel injector ( 10 ) according to any one of the preceding claims, wherein for applying the coupler ( 32 ) with a spring force at least one spring element ( 34 . 36 ) is provided, wherein the spring element ( 34 . 36 ) the spring support part ( 66 ) encloses at least partially circumferentially. Fuel injector ( 10 ) according to one of the preceding claims, wherein the hydraulic coupler ( 54 ) at least one of the coupler space ( 30 ) limiting setting piece ( 28 ), wherein the adjusting piece ( 28 ) at least partially in the Federauflageteil ( 66 ) is guided. Fuel injector ( 10 ) according to any one of the preceding claims, wherein for applying the coupler ( 32 ) with a spring force at least one spring element ( 34 . 36 ) is provided, wherein the hydraulic valve ( 48 ) at least one valve plate ( 24 ), wherein the spring element ( 34 . 36 ) directly on the valve plate ( 24 ) is supported. Fuel injector ( 10 ) according to one of the preceding claims, further comprising at least one valve spring ( 38 ), wherein the valve spring ( 38 ) on the valve stem ( 22 ) and is adapted to the valve rod ( 22 ) to apply a closing force.