JP2003526048A - Fuel high pressure accumulator - Google Patents

Abstract

(57) Abstract: The present invention relates to a fuel high-pressure accumulator for a common rail fuel injection system for an internal combustion engine, comprising a tubular base body (1), It is of the type that at least one bush (13) for connecting the high-pressure line (6) is welded. A flange (14) is formed at the end of the bush (13) on the side facing the base body (1) in order to improve the quality and safety at the high-pressure connection points.

Description

Detailed Description of the Invention

The present invention is a fuel high-pressure accumulator for a common rail fuel injection system of an internal combustion engine, which has a tubular base body, and at least a high-pressure pipe line for connecting to the base body. It relates to a type in which one bush is welded.

High-pressure fuel accumulators of this type are described, for example, in EP 0866221.
No. specification. In the common rail injection system, the high-pressure pump is sometimes assisted by a pre-feed pump to supply the fuel to be injected from a tank to a central fuel high-pressure accumulator as a common rail. Fuel lines lead from the rails of the common rail to the respective injectors, and these injectors are assigned to the cylinders of the internal combustion engine. The injectors are individually controlled by the engine electronics in relation to the operating parameters of the internal combustion engine in order to inject fuel into the combustion chambers of the internal combustion engine.

The object of the invention is to improve the safety and the quality of the high-pressure connection in a fuel high-pressure accumulator of the type mentioned at the outset. Moreover, the fuel high-pressure accumulator according to the present invention must be simple in structure and inexpensive to manufacture.

This problem is a fuel high-pressure accumulator for a common rail fuel injection system of an internal combustion engine, which has a tubular base body, and at least for connecting a high-pressure pipeline to the base body. In the type in which one bush is welded, it is solved by forming a flange at the end of the bush facing the base body.

Advantages of the Invention The flange is used to supply the welding current required to weld the bush. In a conventional bush without a flange, the welding electrode is provided at the end of the flange opposite to the base body. In this case, the welding gun may reach the inside of the bush and damage the screw provided there. Moreover, the internal geometry of the bush deforms undesirably due to the temperatures that occur during welding. Such drawbacks are avoided by designing the flange as the working point for the welding electrode according to the invention. Another advantage resides in that the flange forms a working surface for the force that presses the bush against the base body during welding. Such forces are actually provided by the welding electrode.

In a special embodiment of the invention, a hole opening into the funnel-shaped receiving part extends from the inner chamber of the tubular base body, the funnel-shaped receiving part flaring outwards. Is used to receive the end of the high-pressure line, and the end is high-pressure sealed by a press screw of a substantially hollow cylindrical shape and pressed against the funnel-shaped receiving portion, and the sealing point is a substantially hollow cylindrical shape. It is characterized by being surrounded by an insulating ring.
The insulating ring ensures that the electrical shunt is blocked when welding the bush.
Moreover, the insulating ring ensures that the welding gun does not reach the sealing point when welding the bush.

According to another special embodiment of the invention, the insulating ring is preassembled in the bush, the inner peripheral surface of the insulating ring abutting the outer peripheral surface of the projection, and the funnel in the projection. The shape receiving portion is formed. This allows the bushing to be centered relative to the projection prior to welding during assembly.

According to a special embodiment of the invention, the end of the high-pressure line is constructed spherically,
The inner diameter of the press screw is larger than the outer diameter of the high pressure line. This makes it possible to open the high-pressure line relatively to the bush. This makes it possible to compensate for possible assembly tolerances in the engine compartment.

According to another special embodiment of the invention, the end face side of the bush, which faces the tubular base body, is chamfered inwards. The chamfer reduces access to the connection between the bush and the tubular base body.

Other advantages, features and details of the invention are described in the following description with the drawings. In the following, two embodiments of the present invention are specifically described with reference to the drawings. The features described in the claims and in the description of the embodiments are important to the present invention either individually or in any combination.

FIG. 1 is a cross sectional view of a fuel high pressure accumulator according to a first embodiment of the present invention, and FIG. 2 is a cross sectional view of a fuel high pressure accumulator according to a second embodiment of the present invention. It is shown.

Description of Embodiments The fuel high-pressure accumulator shown in cross-section in FIG. 1 has a tubular base body 1. Longitudinal or longitudinal holes 2 provided in this tubular base body 1 are used for storing fuel loaded at high pressure. A number of lateral holes extend from the longitudinal hole 2, of which only one, namely the lateral hole 3, is shown in FIG. The lateral holes 3 open outwards into the funnel-shaped receptacle 4. The funnel-shaped receptacle 4 is conically shaped and forms the sealing surface for the spherical end 5 of the high-pressure line 6. The spherically shaped end 5 of the high-pressure line 6 transitions into a region 7 having an expanded outer diameter. A high-pressure pipe line 6 of a pressure shoulder 8 is formed outside at a connection portion with a region 7 having an expanded outer diameter.

A recess 9 is in contact with the pressure shoulder 8 of the high-pressure line 6, and the recess 9 is formed on the inner peripheral portion of the end of the press screw 10 on the side facing the tubular base body 1. ing.
The press screw 10 has a substantially hollow cylindrical shape, and the high-pressure pipe line 6 extends through the hollow cylindrical shape. The press screw 10 comprises an external thread 11, which cooperates with an internal thread 12 formed in a hollow cylindrical bush 13.

The bush 13 is provided with a flange 14 at an end thereof on the side facing the tubular base body 1. A chamfered portion 15 is formed on the end face side of the bush 13 of the flange 14 facing the tubular base body 1. The chamfered portion 15 is arranged substantially perpendicular to the concave portion 19 formed on the inner peripheral surface of the bush 13. An annular edge is formed at the transition between the chamfered portion 15 and the recess 19, and this annular edge is rounded and rests on the flat portion 20 formed on the tubular base body 1. ing. The connection between the bush 13 and the tubular base body 1 is made by a weld seam 16.

A protrusion 17 is bulged on the tubular base body 1 at the center of the flat portion 20. The funnel-shaped receiving portion 4 is formed in the center of the protruding portion 17. The protrusion 17 has a cylindrical shape surrounded by an insulating ring 18 on the outside. The insulating ring has the shape of a hollow annular cylinder which fits within the bush 13.

[Brief description of drawings]

[Figure 1]   1 is a cross-sectional view of a fuel high pressure accumulator according to a first embodiment of the present invention.

[Fig. 2]   FIG. 5 is a cross-sectional view of a high pressure fuel pressure accumulator according to a second embodiment of the present invention.

Claims (5)

[Claims] 1. A fuel high-pressure accumulator for a common rail fuel injection system for an internal combustion engine, comprising a tubular base body (1), wherein the base body (1) comprises:
In the type in which at least one bush (13) for connecting the high-pressure line (6) is welded, a flange (14) is provided at the end of the bush (13) facing the base body (1). ) Is formed, the fuel high-pressure accumulator. 2. A funnel-shaped receiving part (4) from the inner chamber (2) of the tubular base body (1).
) Has a hole (3) opening into it, the funnel-shaped receiving part (4) expanding outwards to receive the end (5) of the high-pressure line (6). The end (5) is pressed against the funnel-shaped receiving part (4) by high-pressure sealing with a press screw (10) of a substantially hollow cylindrical shape, and the sealing point is a substantially hollow cylindrical shape. 2. The high-pressure fuel accumulator according to claim 1, which is surrounded by a ring. 3. The insulating ring (18) is preassembled in the bush (13), the inner peripheral surface of the insulating ring (18) abutting the outer peripheral surface of the projection (17), High-pressure fuel accumulator according to claim 2, characterized in that a funnel-shaped receptacle (4) is formed. 4. An end (5) of the high-pressure line (6) is spherically shaped, the inner diameter of the press screw (10) being larger than the outer diameter of the high-pressure line (6). 3. The high-pressure fuel accumulator according to 3. 5. The high fuel pressure according to claim 1, wherein the end surface side of the bush (13) on the side facing the tubular base body (1) is chamfered inward. Accumulator.