DE102016225936A1 - Two-piece leakage connection - Google Patents

Abstract

The invention relates to a leakage connection 60 for a fuel injector 10 for injecting fuel into a combustion chamber of an internal combustion engine, which is characterized in that the leakage connection 60 is formed in two parts.

Description

The present invention relates to a leakage port for an injector for injecting fuel into a combustion chamber of an internal combustion engine.

As fuel supply system for internal combustion engine storage injection systems are often used, which operate at very high injection pressures. In these accumulator injection systems, fuel is conveyed by means of a high-pressure pump into a fuel injector, from which fuel is injected into the combustion chamber of the internal combustion engine. Such a fuel injector has an injection valve in which the opening and closing of the nozzle needle is controlled predominantly by means of a servo valve. This means that opening the servo valve creates a connection from the high-pressure area to the low-pressure area and thus generates a leakage current. This leakage flow must be routed from each injector back into the tank or into the intake area of the high-pressure pump. Even with directly controlled diesel injectors, there is a small, continuous leakage current, which must be fed back into the fuel circuit. For the leakage connection at the injector various installation space and position requirements are to be fulfilled according to the installation conditions on the motor.

For example, a leakage connection inclined to the injector axis for a direct hose connection is known from the prior art, which leakage connection is designed as a straight tube. The disadvantage here is that it can not produce a largely axis-parallel leakage connection. Furthermore, leakage connections are known from the prior art, which are designed as a bent tube, to which by means of an O-ring a liquid-tight plug connection to the leakage discharge line is made. In this case, an axis-parallel leakage connection can be produced, the connection to the injector body is made by a laser weld. A disadvantage of such embodiments, however, is that the necessary material properties in terms of Zerspannbarkeit, formability and weldability can not be optimally combined in one material.

It is therefore an object of the present invention to provide a leakage connection for an injector, which avoids the disadvantages known from the prior art.

This object is achieved by a leakage connection with the features of claim 1. The subclaims show advantageous embodiments of the invention.

The leakage connection according to the invention for an injector comprises a two-part leakage connection. The presence of this bipartite makes it possible to form the leakage connection according to the individual installation conditions of the respective injector, without having to make any changes to the injector as a whole. As a result, for example, space is created for the arrangement of the high-pressure fuel connection at the projecting end of the injector. Due to the two-part design of the leakage connection, it is also possible to facilitate the assembly and disassembly of the return port and thus to improve the reliability of the injector.

In a first development, the leakage connection is formed from two parts, an injector-side tube piece, which is arranged fuel-tight on the injector, and a connection-side connection piece for connection to a leakage discharge line.

As a result, the different requirements for the leakage connection from the injector side and also from the side of the leakage drain line can be realized in the best possible way.

Advantageously, the pipe section and the connecting piece are welded together. This type of connection has the advantage that a favorable course of lines of force can be achieved, and this represents a weight saving compared to other types of connection. Furthermore, a high power transmission is guaranteed even at low seam thicknesses.

The pipe section can thus be carried out uniformly for all different Injektorapplikationen. The leakage connection piece can be made variable to the respective space requirements.

According to a further aspect of the invention, the pipe section and the connecting piece can be laser welded together. Neither the pipe section nor the fitting undergo structural changes hereby and are therefore fairly dimensionally stable.

In order for the leakage connection to be able to be adapted to the respective space requirements, the leakage connection can be formed from a tube piece which is uniform for all injector applications and a connection piece which is variable for the respective leakage discharge line. The tube piece, which represents the connector piece between the injector body and the leakage connector piece, can consequently be designed uniformly for all the different injector applications. On the other hand can For example, the leakage fitting may be formed and used with a direct hose connection or a special plug connection. For this purpose, in turn, it is advantageous if the connecting piece is designed for attaching a hose connection or is designed for connection to a plug connection.

Preferably, the fitting and the pipe piece can be arranged at any angle of between 0 to 180 ° to each other. Thus, also largely axially parallel alignment can be displayed on the injector.

Should the requirements of the leakage discharge line make it necessary, the pipe section and the connecting piece can be made of different materials. The materials can be optimally selected with regard to machinability and weldability. Since the process step bending is eliminated, there is no longer any requirement with regard to plastic formability.

In one development of the invention, the longitudinal axis of the connecting piece and the longitudinal axis of the pipe section can be at an angle of preferably approximately 90 ° to each other, such that the longitudinal axis of the connecting piece extends substantially parallel to the longitudinal axis of the injector. This makes it possible to represent a laterally axis-parallel leakage connection.

• 1 den oberen Teil eines Injektors mit einem Leckageanschluss des Stands der Technik;
• 2 den oberen Teil eines Injektors mit einem weiteren Leckageanschluss des Stands der Technik;
• 3 in einer Seitenansicht den oberen Teil eines Injektors mit dem erfindungsgemäßen zweiteiligen Leckageanschluss;
• 4 eine Schnittansicht des erfindungsgemäßen Leckageanschlusses im zusammengebauten Zustand; und
• 5 eine Seitenansicht des Leckageanschlusses im auseinandergebauten Zustand.

An embodiment of the leakage connection according to the invention is described below; show it:

• 1 the upper part of an injector with a leakage connection of the prior art;
• 2 the upper part of an injector with another leakage connection of the prior art;
• 3 in a side view of the upper part of an injector with the two-part leakage connection according to the invention;
• 4 a sectional view of the leakage connection according to the invention in the assembled state; and
• 5 a side view of the leakage connection in the disassembled state.

According to 1 In a manner known per se, the fuel injector 10a essentially consists of an actuator port 20a, an actuator 30a and an injection nozzle (not shown). In this case, the actuator 30a and the nozzle are arranged in an injector body 40a. Moreover, a high-pressure connection 50a, via which fuel can be supplied under high pressure to the injector 10a, and a one-piece leakage connection 60a are provided on the injector body 40a, via which excess fuel can be removed from the injector 10a.

2 branches off another fuel injector 10b with the 1 known components and another one-piece leakage port 60b. Identical components are here designated by the same reference number, but instead of the letter a with the letter b. The out 1 known leakage connection 60a is formed as a straight tube and is at an angle of less than 90 degrees to the injector 15a from the fuel injector 10a. The leakage port 60b is off 2 is in contrast as a bent tube, also formed in one piece. Both leakage ports 60a, 60b are connected by a weld to the respective injector body 40a, 40b.

In 3 is a fuel injector 10 with a leakage connection 60 shown, which is constructed in two parts and essentially of an injector-side pipe section 70 and a connection-side fitting 80 is constructed. The leakage connection 60 is so on the injector body 40 arranged that a pipe piece axis 90 of the pipe section substantially at an angle of about 90 degrees to the injector body axis 95 is aligned and a connector axis 100 essentially a right angle to the pipe piece axis 90 occupies. However, it is also conceivable that the pipe piece axis 90 and the connector axis 100 are arranged at an angle between 0 to 180 degrees to each other.

According to 4 and 5 indicates the leakage connection 60 on the outer circumference of the pipe section 70 a recess 110 on which for fitting the leakage connection 60 in a corresponding opening of the injector body 40 is executed. On the connection side, the pipe section points 70 the leakage connection 60 also a recess 120 on its outer periphery, which is formed such that it is in a receiving bore 130 of the connector 80 can be fitted. The outer contour of the recess 120 of the pipe section 70 is the inner contour of the mounting hole 130 of the connector 80 customized. The pipe piece 70 and the connector 80 are welded together, preferably via a laser weld 135 connected with each other. At the connection end 140 of the connection piece 80 is a groove 150 formed into which an O-ring can be used to make a liquid-tight connection to a leakage drain line. The connection end 140 can be carried out variably adapted to the respective space requirements. So can the connector 80 For example, be used for a direct hose connection or for a special plug connection.

The in the 3 . 4 and 5 shown leakage connection 60 is as a nearly rectangular leakage connection 60 shown. The execution of the leakage connection 60 is not limited to a rectangular training, but any angle can be displayed in all directions, that is, it is also a largely axially parallel alignment on the injector body 40 represented. Also, the materials for the leakage connection 60 are optimally selected in terms of machinability and weldability and are not limited to a material which has the properties to be optimally suitable both for cutting, for forming and for welding. Since the bending process is eliminated, there is no longer any requirement in terms of plastic formability.

In 4 it can be seen that in the pipe section 70 a bore 160 formed centrally and in the fitting 80 is another hole 170 centrally trained. In the connection area 180 of the pipe section 70 and the connector 80 go the holes 160 . 170 into each other. By dividing the leakage connection into the pipe section 70 and the connector 80 There is the advantage that the length of the holes to be produced 160 . 170 , whose diameter is less than two millimeters, is significantly smaller than, for example, a bore in the extended length of a one-piece bent leakage connection.

LIST OF REFERENCE NUMBERS

10

fuel injector

15

the injector

20

actuator connection

30

actuator

40

injector

50

High pressure port

60

leakage connection

70

pipe section

80

connector

90

Axis of the pipe section

95

Injektorkörperachse

100

Axle of the connector

110

recess

120

recess

130

location hole

135

laser weld

140

connection end of the connection piece

150

groove

160

drilling

170

drilling

Claims (10)

Leakage connection (60) for an injector (10) for injecting fuel into a combustion chamber of an internal combustion engine, characterized in that the leakage connection (60) is formed in two parts. Leakage connection (60) to Claim 1 characterized in that the leakage port (60) is formed of two pieces, an injector-side pipe section (70) which is fuel-tightly disposed on the injector (10), and a connection-side fitting (80) for connection to a leakage drain line. Leakage connection (60) according to one of the preceding claims, characterized in that the pipe section (70) and the connecting piece (80) are welded together. Leakage port (60) according to any one of the preceding claims, characterized in that the tube piece (70) and the connecting piece (80) are laser welded together. Leakage connection (60) according to any one of the preceding claims, characterized in that the leakage connection (60) from a uniform for all Injektoranwendungen pipe piece (70) and a variable for the respective leakage discharge line connector (80) are formed. Leakage port (60) according to any one of the preceding claims, characterized in that the connecting piece (80) is designed for attaching a hose connection. Leakage connection (60) according to one of the preceding claims, characterized in that the connecting piece (80) is designed for connection to a plug connection. Leakage port (60) according to one of the preceding claims, characterized in that the connecting piece (80) and the tube piece (70) are arranged at an angle of 0 to 180 degrees to each other. Leakage port (60) according to one of the preceding claims, characterized in that the pipe section (70) and the connecting piece (80) are formed of different materials. Leakage port (60) according to one of the preceding claims, characterized in that the longitudinal axes (100, 90) of the connecting piece (80) and of the tubular piece (70) are at an angle of preferably approximately 90 ° to each other, such that the longitudinal axis (100) of the connecting piece (80) extends substantially parallel to the longitudinal axis (95) of the injector (10).

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