GB2125888A

GB2125888A - I.C. Engine fuel injection valve

Info

Publication number: GB2125888A
Application number: GB08224580A
Authority: GB
Inventors: Karl Aichele; Wolfgang Kramer; Ernst Lang; Mathias Linssen; Alois Stemmer; Michael Wissmann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1982-08-26
Filing date: 1982-08-26
Publication date: 1984-03-14
Also published as: GB2125888B

Abstract

A swirl insert (41), which has swirl channels (42) is located in the valve outlet bore (40). The swirl channels (42) also serve as metering channels and their throttling length can be varied through displacement of the insert (41) in the bore (40). The insert may take various forms (Figs. 3 to 9). <IMAGE>

Description

SPECIFICATION Injection valve The present invention relates to an injection valve.

In a known injection valve, swirl channels are provided directly in a nozzle body. The drilling operations required in this case are not only expensive, but also imposes limits on the shape and course of the swirl channels.

According to the present invention there is provided an injection valve comprising a nozzle body, a valve seat arranged in the body, a movable valve element co-operable with the seat to control a flow of fluid therethrough, and a swirl insert disposed in the body downstream of the seat and provided with swirl channels to impart a swirl to and to meter such fluid.

An injection valve embodying the present invention may have the advantage of a simple production and assembly to provide an injection valve for spraying with a swirl for simultaneous fuel metering through the swirl channels.

A subsequent possibility of action for the correction of the metering, by adjusting the position of the insert, is particularly advantageous.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a sectional view of an injection valve according to a first embodiment of the invention; Fig. 2 is a cross-section along the line 11-11 in Fig. 1; Fig. 3 is a partly sectional view of part of an injection valve according to a second embodiment of the invention; Fig. 4 is a cross-section along the line IV--IV in Fig. 3; Fig. 5 is a cross-section along the line V-V in Fig. 4; Fig. 6 is a partly sectional view of part of an injection valve according to a third embodiment of the invention; Fig. 7 is a cross-section along the line VIl-VIl in Fig. 6;; Fig. 8 is a cross-section along the line VIll-VIll in Fig. 7; and Fig. 9 is a partly sectional elevation of an injection valve according to a fourth embodiment of the invention.

Referring now to the drawings, there is shown in Fig. 1 a fuel injection valve 1 which is actuable electromagnetically in known manner and which serves for, for example, the injection of fuel, particularly at low pressure, into the air induction duct of a mixture-compressing, external ignition internal combustion engine. Fuel injection through the fuel injection valve can take place either through a single fuel injection valve into the air induction duct, upstream or downstream of a throttle flap, simultaneously for all cylinders of the engine, or through a respective fuel injection valve into individual induction ducts immediately in front of each inlet valve of each cylinder. The electrical drive of the fuel injection valve can take place in known manner through contact pins 3.

The fuel injection valve is mounted in a guide opening 4 of a retaining body 5 and can, for example, be locatable in axial direction through a claw or a lid 7, while a sealing ring 10 rests against an end face 8, remote from the lid 7, of the fuel injection valve and also bears against a step 9 of the body 5. The retaining body 5 can be formed by the induction duct wall itself or be constructed as an independent part. The valve 1 has an annular fuel feed groove 1 2, from which fuel feed openings 1 3 lead into the interior of the valve.

Axially displaced relative to the fuel feed groove 12 and disposed above this groove is an annular fuel removal groove 14, from which fuel removal openings 1 5 lead into the interior of the valve 1. A fuel feed duct 17, which is connected with a fuel supply source, for example a fuel pump, opens into the groove 12. Fuel flowing through the duct 1 7 into the groove 1 2 passes through the openings 13 into the interior of the valve and is either sprayed off into the induction duct or for heat reception flows through the valve and issues through the openings 1 5 into the groove 14, which is connected with a fuel removal duct 1 8 formed in the body 5.The valve is guided in radial direction in the openings 4 of the body 5 by resilient support bodies 19, 20 and 21 of a fuel filter 23, which extends in axial direction to cover the grooves 12 and 14. The bodies 19, 20 and 21 are produced from a resilient material, for example rubber or synthetic material. The centre body 20 in particular is annularly constructed and, for example, provided with sealing lugs 24 so that it bears on the one hand against the circumference of the valve 1 between the grooves 12 and 14 and on the other hand against the wall of the opening 4 thereby to seal the groove 12 and duct 1 7 from the groove 14 and duct 1 8.

Fuel flowing through the duct 1 7 at first passes into an annular groove 25 formed between the centre support body 20 and the lower support body 21 of the fuel filter and can flow out of the groove 25 through the filter region 26 into the groove 12. The fuel can flow out of the groove 14 through the filter region 27 into an annular groove 28, which is formed between the upper support body 19 and the centre support body 20 and which is connected with the fuel removal duct 1 8.

Any foreign bodies in the fuel are filtered out by the filter regions 26 and 27. A simpler processing is provided by, and greater tolerances at the circumference of the valve 1 and the diameter of the opening 4 are permitted through, the resilient structuring of the centre support body 20. The upper support body 1 9 can be provided at its side facing the valve 1 with a detent lug 30 which, on pushing of the filter 23 onto the valve, engages in a detent groove 31 of the valve so that the valve together with the filter placed thereon can be inserted into the opening 4 of the body 5. A sealing ring 33, which is arranged between the valve and the body 5, can bear axially on the upper support body 19 and be located by the lid 7.

The fuel injection valve 1 possesses a movable valve element 35 which is, for example, spherically or part-spherically shaped and cooperates with a correspondingly shaped fixed valve seat 36 in a nozzle body 37. The valve element 35 is lifted off the valve seat when the electromagnet of the valve is excited, so that fuel can flow between the valve element 35 and the valve seat 36 and into a collecting chamber 38, which has the smallest possible volume. A preparatory bore 40, also formed in the nozzle body 37, adjoins the collecting chamber 38. A cylindrical swirl insert 41 is partially pressed into the bore 40 and has swirl channels 42 which are open towards its circumference and which are ciosed off by the wall 43 of the bore 40.The swirl channels 42 extend in axial direction inclined relative to the axis of the injection valve from one insert end 44 in the collecting chamber 38 to the other insert end 45 and open tangentially into the bore portion 46. The fuel is distributed over the wall of the bore portion 46 as a film and flows towards the open end 47, formed with a sharp edge, of the nozzle body 37. From there, the film of fuel still displaying a swirl, separates and enters into the air induction stream, where a uniform intermixing of air and fuel takes place as is prerequisite for low fuel consumption and low proportions of toxic exhaust gas components. The swirl channels 42 at the same time serve as metering channels and have a semi-circular crosssection which passes over rounded off into the circumference of the swirl insert 41, as is illustrated in Fig. 2.In that case, at least two swirl channels 42, displaced at a desired angle from each other, are provided; four swirl channels 42 displaced through 900 relative to each other are shown in Fig. 2. The metered quantity can be influenced by pressing the insert 41 to a greater or lesser extent into the bore 40, since the throttle effect of the channels 42 is dependent on the length of the channels covered over by the wall 43 of the bore 40. A correction of the metered quantity of fuel can thus take place in the assembled state through displacement of the insert 41.

In the case of the second embodiment illustrated in Fig. 3, the fuel injection valve 1 is shown only in part and the parts, which are the same and act in the same manner compared with the embodiment according to Fig. 1, are indicated by the same reference numerals. The collecting chamber 38 in the embodiment according to Fig. 4 passes over into the preparatory bore 40, which has a smaller diameter than the chamber 38, and a step is formed at the transition. A discshaped swirl insert 51, which has an end face 52 resting against the step 50, is arranged in the chamber 38. As is also illustrated in Figs 4 and 5, swirl channels 53, which are open towards the end face 52 and are covered over by the annular step 50, are formed in the end face 52.The channels 53 extend substantially horizontally and open tangentially into the bore 40, from which the fuel issues, as a swirl in the form of a film, into the air current. According to Fig. 4, four swirl channels 53 are provided in the insert 51, the channels being displaced from each other through 90 and extending parallel to the axis of the end face at a spacing which corresponds to the radius of the bore 40. The channels 53 start at the circumference of the insert 51 and end, as a blind hole, in an arc 54 towards the end face 52.

In the third and fourth embodiments according to Figs. 6, 7, 8 and 9, which also show only part of the valve, a pot-shaped swirl insert 57, which is formed from sheet metal by, for example, deepdrawing, is pressed into a receiving bore 56 in the nozzle body 37, the bore 56 adjoining the collecting chamber 38. Swirl channels 59 are shaped out in the base wall 58 of the swirl insert 57 and open, inclined relative to the longitudinal axis of the injection valve, into a receiving bore 61 defined by the cylindrical wall 60 of the insert 57.

From the bore 61, the fuel issues with swirl distributed in the form of a film into the air current.

The swirl channels 59 serve, as do the swirl channels 53 of the second embodiment, as metering channels. Four swirl channels 59 displaced through 90 relative to each other are illustrated in Fig. 7. As is illustrated in Fig. 8, the opening 62 of each channel 59 is formed by bending out a portion of the base wall 58 into the interior of the insert 57, i.e. into the bore 61.

In the case of the swirl insert 57 shown in Fig. 9, the base wall 58 is provided with an oblique portion 63, from which the swirl channels 59 start out at the collecting chamber 38 and lead in the form of bores to the preparatory bore 61.

Through the arrangement of a swirl insert 41, 51 or 57 in the afore-described embodiments, the production and assembly of a fuel injection valve providing fuel injection in swirl mode is possible in a simple manner.

Claims

1. An injection valve comprising a nozzle body, a valve seat arranged in the body, a movable valve element co-operable with the seat to control a flow of fluid therethrough, and a swirl insert disposed in the body downstream of the seat and provided with swirl channels to impart a swirl to and to meter such fluid.

2. A valve as claimed in claim 1, wherein the insert is pressed into a fluid preparation bore provided in the body downstream of the seat, the channels being open at the external circumference of the insert and extending between two opposite ends of the insert at an angle to the axis of the bore so as to tangentially open into the bore.

3. A valve as claimed in claim 2, wherein the insert is pressed into the bore to a selected extent having a predetermined influence on metering of the fluid by the channels.

4. A valve as claimed in claim 1 wherein the body is provided downstream of the seat with a fluid collecting chamber and downstream of the chamber with an adjoining fluid preparation bore of smaller diameter than the chamber, the insert being disposed in the chamber with a face of the insert against a step between the chamber and the bore of the channels being arranged in said face and opening tangentially into the bore.

5. A valve as claimed in claim 1, wherein the insert is substantially pot-shaped and is so pressed into a receiving bore provided in the body downstream of the seat that the base wall of the insert faces the seat, the channels being formed in the base wall to extend at an angle to the axis of the bore so as to open into a fluid preparation space enclosed by a substantially cylindrical side wall of the insert.

6. A valve as claimed in any one of the preceding claims, wherein each of the channels is substantially semi-circular in cross-section.

7. a valve as claimed in either claim 2 or claim 3, wherein the walls of the channels are rounded at the zones of conjunction thereof with the circumferential surface of the insert.

8. A valve as claimed in any one of the preceding claims, the valve being adapted to serve as a fuel injection valve in a fuel injection system of an internal combustion engine.

9. A valve substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

1 0. A valve substantially as hereinbefore described with reference to Figs. 3 to 5 of the accompanying drawings.

11. A valve substantially as hereinbefore described with reference to Figs. 6 to 8 of the accompanying drawings.

12. A valve substantially as hereinbefore described with reference to Fig. 9 of the accompanying drawings.