EP3867519A1

EP3867519A1 - Injector arrangement

Info

Publication number: EP3867519A1
Application number: EP19786771.6A
Authority: EP
Inventors: Heinrich Werger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-10-17
Filing date: 2019-10-10
Publication date: 2021-08-25
Anticipated expiration: 2039-10-10
Also published as: FI3867519T3; EP3867519B1; US20210381478A1; DE102018217768A1; CN112912611A; CN112912611B; WO2020078817A1; US11536234B2

Abstract

The invention relates to an injector arrangement (1) having an injector nozzle (2) for injecting medium into a combustion chamber (3), particularly for injecting fuel into a combustion chamber (3) of an internal combustion engine, and having a sealing ring (20), which is pre-loaded in order to seal against a sealing surface (6) of a cylinder head (4), which comprises a through-hole (5), through which the injection nozzle (2) protrudes into the combustion chamber (3) and in which, in the radial direction between the injection nozzle (2) and the cylinder head (4), a heat protection sleeve (10) is arranged, one end (11) of which, facing the combustion chamber (3), is frictionally connected to the injection nozzle (2) by a radial pressing (12). In order to functionally improve the injector arrangement (1), an end (13) of the heat protection sleeve (10) furthest from the combustion chamber (3) is frictionally connected to the sealing ring (20) by an axial pressing (14).

Description

description

title

Injector arrangement

The invention relates to an injector arrangement with an injection nozzle for

Injecting medium into a combustion chamber, in particular for injecting fuel into a combustion chamber of an internal combustion engine, and with a sealing ring that is biased for sealing against a sealing surface of a cylinder head, which comprises a through hole through which the injection nozzle enters the

Combustion chamber protrudes and in which a heat protection sleeve is arranged in the radial direction between the injection nozzle and the cylinder head, which is connected non-positively to the injection nozzle by radial pressure at one end facing the combustion chamber.

State of the art

From the Austrian patent AT 512 667 Bl an injection nozzle for injecting medium into a combustion chamber is known, in particular from

Fuel in the combustion chamber of an internal combustion engine, comprising a

Nozzle body, the nozzle tip having the spray holes in the

Comes into the combustion chamber, a heat protection sleeve arranged in the end region of the nozzle body on the combustion chamber, which surrounds the nozzle body, the

Injection nozzle in a receiving bore of a holding part, in particular

Cylinder head is used, the combustion chamber end region of the nozzle body with the interposition of the heat protection sleeve with the

Receiving hole cooperates, wherein the heat protection sleeve has a first and a second region, which are axially spaced from each other, the second region being arranged closer to the nozzle tip than the first region, with a first outer on the outer jacket in the first region

circumferential sealing surface and on the inner jacket a first inner circumferential sealing surface are formed and in the second area

Outer jacket a second outer circumferential sealing surface and on

Inner jacket are formed a second inner circumferential sealing surface, the second sealing surfaces having a smaller diameter than the first sealing surfaces, the first outer and the second outer sealing surface each sealingly with an annular seat surface running in a radial plane or with a conical seat surface of the receiving bore Cooperate and the first inner and the second inner sealing surface each sealingly cooperate with an annular seat surface running in a radial plane or with a conical seat surface of the nozzle body. From the European patent EP 3 014 105 Bl is a fuel injector, in particular a

Common rail injector, known, with an injector housing that in a

Receiving opening of a cylinder head of an internal combustion engine can be used and, in the installed position, has a first region facing a combustion chamber of the internal combustion engine, to which at least a second region of enlarged diameter is connected on the side facing away from the combustion chamber, the first region being made of metal and on which

Combustion chamber-facing side is radially surrounded by a first sealing element, which in the annular space between the first region of the

Injector housing and the receiving opening in the area of a first

Bore section of the receiving bore can be used, and with a second sealing element, which on the side facing away from the combustion chamber between the injector housing and a contact surface of the receiving opening for the

Injector housing is axially clampable, the first sealing element being axially between the injector housing and a second contact surface

Receiving opening can be tensioned and is designed to seal the annular area between the injector housing and the receiving bore on the side of the first sealing element facing away from the first area, the two sealing elements on a component in the form of a metal

existing sealing sleeve are formed so that the sealing sleeve on the end facing the combustion chamber a conical first

Has sealing area as the first sealing element, while the flange-shaped peripheral edge on the other end face of the sealing sleeve forms a second sealing area or a second sealing element. From the publication of the German translation DE 11 2014 003 643 T5 der International publication WO 2015/020790 discloses an internal combustion engine with a fuel injector arrangement for mounting in an engine cylinder head, comprising: an engine cylinder head sealing surface, a fuel injector body, which has a longitudinal axis

Has nozzle element housing and a nozzle holder; and a

The injector seal arrangement, which is positioned between the fuel injector body and the engine cylinder head, wherein the injector seal arrangement is a sealing component formed from a first material, which in a longitudinal between the fuel injector body and the

Engine cylinder head sealing surface is positioned to receive a fuel injector clamping force, and has a thermally conductive component, which is formed from a second material that is different from the first material, wherein the second material has a higher thermal conductivity than the first material and wherein the thermally conductive component is positioned radially between the nozzle element housing and the sealing component to transfer heat from the nozzle element housing to the sealing component.

Disclosure of the invention

The object of the invention is to provide an injector arrangement with an injection nozzle, for injecting medium into a combustion chamber, in particular for injecting fuel into a combustion chamber of an internal combustion engine, and with a sealing ring which is biased for sealing against a sealing surface of a cylinder head and which has a through hole by which the

Injection nozzle protrudes into the combustion chamber and in which a heat protection sleeve is arranged in the radial direction between the injection nozzle and the cylinder head, which sleeve is connected to the injection nozzle in a force-locking manner with an end facing the combustion chamber by radial pressure.

The task is for an injector arrangement with an injection nozzle for

Injecting medium into a combustion chamber, in particular for injecting fuel into a combustion chamber of an internal combustion engine, and with a sealing ring which is prestressed for sealing against a sealing surface of a cylinder head, which comprises a through hole, through which the injection nozzle protrudes into the combustion chamber and in which a heat protection sleeve is arranged in the radial direction between the injection nozzle and the cylinder head, which is connected non-positively to the injection nozzle with an end facing the combustion chamber by radial pressure that the heat protection sleeve is non-positively connected to the sealing ring with an end facing away from the combustion chamber by an axial pressure. The injection nozzle is also referred to as an injector and comprises a nozzle body in which one

Nozzle needle can be moved back and forth in the direction of a longitudinal axis of the injection nozzle in order to open or close injection openings or injection holes through which a medium under high pressure, such as fuel, can be injected into the combustion chamber. The terms axial and radial refer to the longitudinal axis of the injection nozzle. Axial means in the direction or parallel to the longitudinal axis of the injection nozzle. Radial means transverse to the longitudinal axis of the injection nozzle. The injector arrangement is advantageously used in the operation of modern internal combustion engines for injecting high-pressure fuel, in particular diesel fuel and / or gas, into the combustion chamber. In the context of the present invention

Tests and examinations carried out have found that, in a conventional injector arrangement, fuel gas from the combustion chamber along an annular gap between the heat protection sleeve and the sealing ring into an annular space on a side of the combustion chamber facing away from the combustion chamber

Can lick heat protection sleeve. When the gas in the annular space cools down, it can happen that aggressive media separate from the fuel gas, which can cause corrosion on the parts delimiting the combustion chamber, which is undesirable. The axial pressure creates a tight connection between the heat protection sleeve and the sealing ring. In this way, an undesired passage of fuel gas between the heat protection sleeve and the sealing ring can be reliably prevented. In this way, in addition to the known heat dissipation function, a sealing function can be implemented with the heat protection sleeve.

A preferred embodiment of the injector arrangement is characterized in that the heat protection sleeve is prestressed in the axial direction together with the sealing ring against the sealing surface of the cylinder head. So can An axial pressure between the sealing ring and the cylinder head can be represented via the heat protection sleeve. This further improves the seal against undesired passage of fuel gas from the fuel gas.

Another preferred exemplary embodiment of the injector arrangement is characterized in that the heat protection sleeve has at its end facing away from the combustion chamber a radially outwardly projecting collar, by means of which the heat protection sleeve is non-positively connected to the sealing ring.

Radially outwards means that the collar of the heat protection sleeve is directed away from the longitudinal axis of the injection nozzle. In this way, an axial interference fit between the heat protection sleeve and the sealing ring is created in a simple manner.

Another preferred exemplary embodiment of the injector arrangement is characterized in that an annular space, which is formed in the radial direction between the heat protection sleeve and the cylinder head, is delimited in the axial direction at its end facing away from the combustion chamber by the radially outwardly projecting collar of the heat protection sleeve. This reliably prevents an undesired passage of fuel gas from the combustion chamber at the end of the annular space facing away from the combustion chamber. At its end facing the combustion chamber, the annular space is structurally open.

Another preferred exemplary embodiment of the injector arrangement is characterized in that the sealing ring has a radially inwardly projecting collar, which extends in the axial direction between the radially outwardly projecting collar of the heat protection sleeve and the sealing surface of the cylinder head

is clamped. Radially inwards means that the collar of the sealing ring is directed towards the longitudinal axis of the injection nozzle. The collar of the sealing ring preferably has an essentially rectangular ring cross section. The collar of the heat protection sleeve advantageously also has an essentially rectangular ring cross section. The two collars make it possible to display an axial press fit with the sealing ring and the heat protection sleeve in a simple manner. A further preferred exemplary embodiment of the injector arrangement is characterized in that a radial dimension of the inwardly projecting collar of the sealing ring is at least as large as the axial dimension of the radially outwardly projecting collar of the heat protection sleeve. The axial dimension of the radially inwardly projecting collar of the sealing ring is advantageously somewhat larger than the radially outwardly projecting collar of the heat protection sleeve. The axial dimension of the entire sealing ring is advantageously a little more than twice as large as the axial dimension of the heat protection sleeve.

Another preferred exemplary embodiment of the injector arrangement is characterized in that there is a radial play between the radially outwardly projecting collar of the heat protection sleeve and the sealing ring. As a result, the representation of a radial press fit between the

Heat protection sleeve and the injector simplified. The heat protection sleeve is particularly advantageously surrounded radially on the outside by an annular space. This annular space is delimited radially on the outside by the through hole in the cylinder head and by the sealing ring.

A further preferred exemplary embodiment of the injector arrangement is characterized in that the heat protection sleeve comprises a sleeve body which has the shape of a straight hollow cylinder with an inner circumferential surface, with which the heat protection sleeve is pressed over its entire axial dimension against an outer circumferential surface of the injection nozzle. This ensures an extremely stable radial press fit between the injection nozzle and the heat protection sleeve. In addition, the entire inner lateral surface of the heat protection sleeve can be used for the heat transfer between the injection nozzle and the heat protection sleeve.

Another preferred embodiment of the injector arrangement is characterized in that the heat protection sleeve and the sealing ring in the axial direction between the sealing surface of the cylinder head and one

Nozzle clamping nut are clamped. The radially outward collar of the heat protection sleeve is together with the radially inward collar of the sealing ring between the sealing surface of the cylinder head and the Nozzle clamp nut clamped. The nozzle clamping nut is used in a manner known per se to mount the injection nozzle in the cylinder head.

The invention further relates to a heat protection sleeve and / or a sealing ring for a previously described injector arrangement. The heat protection sleeve and the sealing ring can be traded separately.

The invention also relates to a kit for a preliminary

described injector arrangement. The kit for the injector arrangement advantageously comprises different heat protection sleeves and sealing rings. In this way, the injector arrangement can be easily connected to different ones

Installation specifications and / or operating specifications can be adjusted.

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

Brief description of the drawing

Show it:

1 shows an injector arrangement with an injection nozzle and with a

Heat protection sleeve, which is connected to an end facing a combustion chamber by a radial pressure with the injection nozzle, wherein the heat protection sleeve is non-positively connected to an end facing away from the combustion chamber by an axial pressure with a sealing ring, im

Longitudinal cut;

Figure 2 is a similar representation as in Figure 1 with an optimized

Heat protection sleeve; and

3 shows a representation similar to that in FIGS. 1 and 2 with a further optimized heat protection sleeve. Description of the embodiments

In Figures 1 to 3 is an injector arrangement 1; 31; 41 in three similar versions each shown in longitudinal section. The same reference numerals are used to designate the same or similar parts. First, the similarities of the embodiments are described. The differences between the individual embodiments are then discussed.

The injector arrangement 1; 31; 41 comprises an injection nozzle 2, which projects with a lower end in FIGS. The internal combustion engine comprises a cylinder head 4 with a through hole 5, through which the injection nozzle 2 projects into the combustion chamber 3.

The cylinder head 4 has a sealing surface 6 facing away from the combustion chamber 3. The sealing surface 6 extends in a plane perpendicular to a longitudinal axis 8 of the injection nozzle 2. The injection nozzle 2 comprises a nozzle body 9, in which a (not visible or not shown) nozzle needle can be moved back and forth in the direction of the longitudinal axis 8 in order to (likewise through holes or not visible or not shown)

Open or close passage openings for fuel in the nozzle body 9.

The structure and the function of the injection nozzle 2 can be similar to that of the fuel injector disclosed in the European patent specification EP 3 014 105 B1 or the injection nozzle described in the Austrian patent specification AT 512 667 B1.

A heat protection sleeve 10 is assigned to the nozzle body 9 of the injection nozzle 2 in a manner known per se. The heat protection sleeve 10 is formed from a good heat-conducting material, for example from a copper alloy. Heat is dissipated from the nozzle tip of the injection nozzle 2 via the heat protection sleeve 10. The heat protection sleeve 10 is non-positively connected to the nozzle body 9 of the injection nozzle 2 at one end 11 facing the combustion chamber 3 by radial pressure 12. The heat protection sleeve 10 is at one

End 13 facing away from combustion chamber 3 by axial pressure 14

non-positively connected to a nozzle clamping nut 15 and a sealing ring 20. The sealing ring 20 is in turn non-positively connected to the cylinder head 4. The nozzle clamping nut 15 serves, in a manner known per se, to mount the injection nozzle 2 in the cylinder head 4.

The heat protection sleeve 10 has a collar 16 at its end 13 facing away from the combustion chamber 3. The collar 16 extends radially outward from a base body 17 of the heat protection sleeve 10. The base body 17 of the

Heat protection sleeve 10 has essentially the shape of a straight

Hollow cylinder. The collar 16 has a rectangular ring cross section. At its end 11 facing the combustion chamber 3, the heat protection sleeve 10 has an end section 18 with a reduced diameter.

The reduced diameter end section 18 serves to represent the radial pressure 12 between the heat protection sleeve 10 and the injection nozzle 2. The collar 16 of the heat protection sleeve 10 serves to represent the axial pressure between the heat protection sleeve 10 and the sealing ring 20th

The through hole 5 in the cylinder head 4, together with the sealing ring 20, delimits an annular space 19 radially on the outside, which is delimited radially on the inside by the heat protection sleeve 10. The annular space 19 is open towards the combustion chamber 3. At its end facing away from the combustion chamber 3, the annular space 19 is delimited by the collar 16 of the heat protection sleeve 10.

The sealing ring 20 comprises a base body 21 with a rectangular

Ring cross-section. A collar 22 extends radially inward from the base body 21 of the sealing ring 20. The collar 22 of the sealing ring 20 is clamped non-positively in the axial direction between the collar 16 of the heat protection sleeve 10 and the sealing surface 6 of the cylinder head 4. Due to the axial pressure 14, the heat protection sleeve 10 is non-positively connected to the sealing ring 20, which in turn is non-positively connected to the cylinder head 4. As a result, an axial press fit is created which reliably prevents fuel gas from the combustion chamber 3 from reaching the annular space 19 into an annular space 23 which is due to its construction.

The annular space 23 is delimited axially at the bottom by the collar 22 of the sealing ring 20 in FIGS. 1 to 3. The annular space 23 is axially above

Nozzle clamping nut 15 limited. The annular space 23 results from a structurally required radial play between the collar 16

Heat protection sleeve 10 and the base body 21 of the sealing ring 20.

In the injector arrangements 31; 41 of Figures 2 and 3 includes the

Heat protection sleeve 10 a sleeve body 32, which has the shape of a straight hollow cylinder. The sleeve body 32 lies over its entire axial

Dimension, which is also referred to as length, with an inner circumferential surface 33 on an outer circumferential surface 34 of the nozzle body 9 of the injection nozzle 2 in a force-fitting manner in order to represent the radial pressure 12. At its end 11 facing the combustion chamber 3, the sleeve body 32 has an im

Reduced diameter end portion 18.

In the injector arrangement 41 in FIG. 3, in contrast to FIG. 2, the sleeve body 32 is designed without the end section 18 with reduced diameter. Otherwise, the heat protection sleeve 10 in FIG. 3 is designed in exactly the same way as in FIG. 2.

Claims

Expectations

1. injector arrangement (1; 31; 41) with an injection nozzle (2) for injecting medium into a combustion chamber (3), in particular for injecting fuel into a combustion chamber (3) of an internal combustion engine, and with a sealing ring (20), which is prestressed for sealing against a sealing surface (6) of a cylinder head (4), which comprises a through hole (5) through which the injection nozzle (2) protrudes into the combustion chamber (3) and in which there is a radial direction between the injection nozzle (2 ) and the cylinder head (4) a heat protection sleeve (10) is arranged, which is non-positively connected to the injection nozzle (2) with an end (11) facing the combustion chamber (3) by a radial pressure (12), characterized in that the Heat protection sleeve (10) with an end (13) facing away from the combustion chamber (3) is non-positively connected to the sealing ring (20) by an axial pressure (14).

2. Injector arrangement according to claim 1, characterized in that the heat protection sleeve (10) is biased in the axial direction together with the sealing ring (20) against the sealing surface (6) of the cylinder head (4).

3. Injector arrangement according to one of the preceding claims, characterized in that the heat protection sleeve (10) at its end facing away from the combustion chamber (3) (13) has a radially outwardly projecting collar (16) through which the heat protection sleeve (10) is non-positively connected the sealing ring (20) is connected.

4. Injector arrangement according to claim 3, characterized in that an annular space (19), which is formed in the radial direction between the heat protection sleeve (10) and the cylinder head (4), at its end facing away from the combustion chamber (3) (13) in the axial direction Direction of the radially outwardly projecting collar (16) of the heat protection sleeve (10) is limited.

5. Injector arrangement according to claim 3 or 4, characterized in that the sealing ring (20) has a radially inwardly projecting collar (22) in the axial direction between the radially outwardly projecting collar (16) the heat protection sleeve (10) and the sealing surface (6) of the cylinder head (4) is clamped.

6. Injector arrangement according to claim 5, characterized in that an axial dimension of the radially inwardly projecting collar (12) of the sealing ring (20) is at least as large as the axial dimension of the radially outwardly projecting collar (16) of the heat protection sleeve (10) .

7. Injector arrangement according to one of claims 3 to 6, characterized

characterized in that there is a radial play between the radially outwardly projecting collar (16) of the heat protection sleeve (10) and the sealing ring (20).

8. Injector arrangement according to one of the preceding claims, characterized in that the heat protection sleeve (10) comprises a sleeve body (32) which has the shape of a straight hollow cylinder with an inner lateral surface (33) with which the heat protection sleeve (10) over its entire axial dimension is pressed against an outer circumferential surface (34) of the injection nozzle (2).

9. Injector arrangement according to one of the preceding claims, characterized in that the heat protection sleeve (10) and the sealing ring (20) are clamped in the axial direction between the sealing surface (6) of the cylinder head (4) and a nozzle clamping nut (15).

10. Heat protection sleeve (10) and / or sealing ring (20) for an I

Projector arrangement according to one of the preceding claims.