JPH0233469A - Fuel injection nozzle for internal combustion engine - Google Patents

Abstract

PURPOSE: To improve efficiency and emission and restrain noise by forming, on the outer circumference of a valve sleeve, longitudinal grooves from the location of a control flank through a lower end surface edge. CONSTITUTION: Longitudinal grooves 76 are formed from the location of a radial control flank 78 through a lower end surface edge, on the outer circumference of a valve sleeve 34. Thus, it is possible to compare the shapes, dimensions, numbers and injection directions of fuel injection flows of the main injection process and the pre-injection process, therefore it is possible to allow fuel adjustment and distribution to be varied within a wide range. Hence, it is possible to improve efficiency, emission value and fuel consumption value, and restrain noise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fuel injection nozzle for an internal combustion engine, which is provided with a needle valve movably supported within the nozzle body, the needle valve having a closing spring. is pressed against the valve seat fixed to the casing against the flow of fuel, and is loaded in the direction of fuel flow by the fuel, and further upstream of the closing head of the needle valve in the nozzle body. A movably mounted valve sleeve is provided, the upstream end section of which projects into the fuel-filled pressure chamber, and the downstream end edge of which extends into the fuel-filled pressure chamber. A wall recess is provided in the valve sleeve, which is pressed against the closing head of the needle valve by a spring element and forms an injection channel for the bundled fuel pre-injection stream; The opening of the needle valve is controlled by lifting the closing head of the needle valve from a valve seat fixed to the casing at the beginning of the stroke, and at least one main injection channel is provided which is guided from the pressure chamber through the valve sleeve to the valve opening. The invention also relates to a type in which this main injection passage is controlled by a control part formed in the valve sleeve, which controls the opening of this passage after the pre-injection stroke of the needle valve.

[Conventional technology]

Already according to patent application P 3719459.3, the injection opening for the fuel pre-injection stream is provided by a groove-like cutout in the annular edge of the valve sleeve, which is pressed onto the closing head of the needle valve. It is formed. Said injection opening is controlled open by a closing head which is lifted from a valve seat fixed to the casing at the beginning of the injection stroke and then remains open throughout the entire opening stroke of the needle valve. As a result, during the main injection process, fuel is additionally discharged through the injection openings provided for the pre-injection and adapted to the needs thereof. This can be disadvantageous in many cases. Furthermore, in the +11 injection nozzle according to the above-mentioned patent application P 5719459.3, it is not possible to interrupt the injection for a short time at the transition of these processes in order to clearly contrast the pre-injection process with the main injection process. .

[Problem to be solved by the invention]

The object of the invention is to eliminate the above-mentioned drawbacks.

[Failure to solve the problem]

The configuration of the present invention that solves the above problems is as described in claim 1.

[Action and effect]

According to the device according to the invention, having the features as claimed in claim 1,
It is possible to compare the shapes, sizes, numbers, and injection directions of the fuel injection flows in the main injection process and the pre-injection process by easy means. Thereby, the metering and distribution of fuel can be varied over a wide range to improve efficiency and noise suppression as well as fuel consumption and emission values.

Advantageous embodiments of the device according to claim 1 are possible with the features recited in claim 2 and below.

A control edge in the valve sleeve that controls the main injection passage is relative to one or more control edges at the end of a longitudinal passage provided around the valve sleeve as injection openings for the fuel pre-injection flow. It is particularly advantageous if the injection is arranged such that there is a short interruption in the injection between the pre-injection phase and the main injection phase.

Opposed to the valve sleeve is a stop fixed to the casing, said stop stopping the movement relative to the continuously moving needle valve before the full opening stroke of the needle valve has been completed. If the above-mentioned valve sleeve is forced, the fuel is injected as an umbrella jet during the main injection process, or the umbrella jet additionally overlaps the fuel jet at the end of the opening stroke of the needle valve. be done.

The claims 4 to 10 contain advantageous design details.

〔Example〕

The invention will now be explained with reference to the illustrated embodiment.

The injection nozzle according to FIGS. 1 and 2 has a nozzle body 10 which is fastened to a nozzle holder 14 by means of a nozzle nut 12. FIG. The nozzle holder 14 has a connecting pipe for fuel supply, which is not shown in the drawings. In the nozzle body 10 described above, the needle valve 18
is movably supported by means described in more detail below and has a closing head 20 at its end facing the combustion chamber. The closing head 20 has a conical valve seat surface 22 (second
), the valve seat surface 22 is pressed by means of a closing spring 24 onto a valve seat 26 formed in the nozzle body 10 as a sealing edge. The closing spring 24 is connected to the annular disc 2
7 on the annular shoulder 28 of a bushing 30 inserted into the nozzle body 10 and engages via a support 31 in the upper end of the needle valve 18 . At its upper end, the needle valve 18 is guided in a collar-like projection 32 of the bushing 30. In the illustrated closed position of the needle valve 18, the support 31 has an axial spacing hg with respect to the upper end surface of the bushing 30;
g corresponds to the complete stroke of the needle valve 18.

The combustion chamber side end section of the needle valve 18 is a valve sleeve 34.
The valve sleeve 34 is sealed and supported with a movable play in the bore 36 of the nozzle body 10. The hole 36 is fixedly held on the bottom wall 38 by the bottom wall 3830 of the nozzle body 10 without any play, and has a bottom 44 with a hole 46 and a hole recessed into the lower end surface of the body 42 in the axial direction. A wall section 48 is provided which, together with the bottom wall 38 of the nozzle body 10, is annularly bounded in the axial direction. Needle section 18a of needle valve 18 and bushing 3 of small diameter
An annular chamber 60 formed between the guide hole 62 and the guide hole 62 opens into the chamber 58 described above. This annular chamber 60 is
It communicates via a hole 64 in the nozzle holder 14 with a chamber 66 in the nozzle holder 14 which receives the closing spring 24. A hole 68 leads from this chamber 66 to a connecting pipe provided in the nozzle holder 14 for supplying fuel.

Chamber 58 receives a compression spring 70 which is supported by bushing 30 and which engages an annular rib 72 of valve sleeve 34.

The lower end edge 74 of the valve sleeve 34 is bounded by a conical end surface 9 which interacts with the valve seat surface 22 on the closing head 20 of the needle valve 18 . The compression spring 7U is adjusted to be weaker than the closing spring 24 and presses the valve sleeve 34 against the closing head 20 during the injection pause. In this case, the closing lever 20 rests firmly against the valve seat 26 by means of the closing spring 24. In the illustrated closed position, the annular collar 72 has a distance a with respect to the bottom 44 fixed to the casing;
is slightly smaller than the total stroke hg of the needle valve 18.

A longitudinal groove T6 is formed on the outer periphery of the valve sleeve 34, which longitudinal groove 76 starts at the radial control flank γ8 and opens into the lower end edge 74. In the illustrated closed position, the control flank 78 has a spacing hV1 with respect to the control edge 80 of the bottom wall 38, which spacing hv□
corresponds to the pre-injection stroke of the needle valve 18. Additionally, the valve sleeve 34 has a radial control hole 82;
This control hole 82 has a small diameter needle valve section 18b.
and into an annular chamber 84 between the valve sleeve 34 and the valve sleeve 34 . At the above m control hole 82 chain position, this 1 control edge 86
has a spacing hv2 with respect to the control edge 88 of the TFF body 42, which spacing hv2 is slightly larger than the spacing hV1. The lower end edge 74 of the valve sleeve 34 has a
One or more edge grooves 90 are formed, which edge grooves 90 lead from the annular chamber 84 to the valve seat 26 .

The mode of operation of the injection nozzle described above is as follows: At the beginning of the injection process, the increasing fuel pressure exerts a force on the needle valve 18 that exceeds the differential force between the closing spring 24 and the compression spring 70. 18 and the valve sleeve 34 move downward together, and the bundled fuel pre-injection flow first enters the longitudinal groove 7.
6 and is injected into the combustion chamber in a predetermined direction. A plurality of longitudinal grooves 76 may be provided in the valve sleeve 34 to create a plurality of pre-injection flows, optionally with four longitudinal grooves 76.
The positions of the nozzles 76 in the circumferential direction, their lengths, and their angular positions with respect to the generatrix may be different from each other. (When the needle valve and valve sleeve advance through the forward stroke hv1, the vertical groove 76
The control flank γ8 enters the hole 36, thereby terminating the pre-injection. In the above-described position of the needle valve 1d and the valve sleeve 34, the control hole 82 is still completely closed to the hole 4.
6, as a result of which injection is temporarily substantially interrupted.

During the subsequent stroke of the needle valve 18, the control edge 86 of the control hole 820 reaches the area of the pressure chamber 50, so that fuel flows into the annular chamber 84, from which one or possibly several Via the edge 1f 490, the pre-injection flow reaches the combustion chamber in the form of a linear jet with a different position and groove cross section. This phase, in which a portion of the main injection quantity of fuel has already been injected, continues until the needle valve 18 and the valve sleeve 34 have progressed through stroke a and the annular collar 72 of the valve sleeve 34 abuts the insert 42. . As the opening stroke progresses further, the valve sleeve 34 stops relative to the needle valve 18, which continues to move. This causes the annular gap between the lower control edge 74 and the closure head 20 to be controlled open,
The remaining main injection quantity of fuel, which is injected under high pressure, is additionally injected into the combustion chamber in the form of an umbrella jet. At the end of the injection process, the needle valve and the valve sleeve move in the reverse order to that described above.

In the embodiment according to FIG. 6, a pressure chamber 94 in the nozzle body 96
is connected to the annular chamber 10 between the needle valve 100 and a valve sleeve 104 movably supported within the nozzle body 96 via a passage formed in the needle valve 100 by the flat surface 98 .
2 is always in communication. Pre-injection is effected by one or more longitudinal grooves 106 formed on the outer circumference of the valve sleeve 104 and opening into the partial annular restraint 108 upstream. The upper annular edge 110 of the above-mentioned partial annular groove ILI8 acts as a control edge in the closed position of the needle valve 1t) It has a spacing corresponding to the pre-stroke and rests on the opening of the guide hole of the valve sleeve 104 into the pressure chamber 94 .

The square sleeve 104 further has an annular collar 114, and when the needle valve 100 and the valve sleeve 104 move through a stroke C that is slightly larger than the spacing between them, the annular collar 11
4 abuts against the bottom 115 of the pressure chamber 94.

The valve sleeve 104 is connected to the needle valve 1 by a spring 116.
00 closure head 118. Valve sleeve 10
The end wall of the combustion chamber 4 is formed in a conical shape, and the cone angle d of this conical end wall is equal to the valve seat surface 11 which is also formed in a conical shape at the closing head 118 of the needle valve 100.
It is thicker than the cone angle e of 7. Thereby, needle valve 1
00 and its inner bore edge 120 , the valve sleeve 104 abuts the closing head 118 , so that in a position where the flute or grooves 106 open into the lower end wall of the valve sleeve 104 . Also, the sealing of the annular chamber 102 during the pre-injection process takes place satisfactorily.

When the needle valve 1υ0 is lifted from the valve seat 122 fixed to the casing during the opening stroke of the injection nozzle, first the longitudinal groove 106 forming the front injection passage becomes free. After the pre-stroke is performed, the vertical groove 106 is controlled to close, and the injection is temporarily interrupted. After the valve sleeve 104 has rested on the nozzle body 96, the annular gap between the valve sleeve 104 and the closing head 118 is opened, through which the main fuel quantity is injected in the form of an umbrella jet.

In the embodiment according to FIG. 4, a spring-loaded valve sleeve 124 without an annular collar is provided, which follows the needle valve 126 without support over its entire opening stroke. In this embodiment as in the embodiment described above, pre-injected fuel flows from the pressure chamber 127 to the partial annular groove 128 and the valve sleeve 12.
4 into the combustion chamber through at least one longitudinal groove 130 formed around the periphery of the combustion chamber. The main injection, on the other hand, takes place via the other longitudinal groove 132 of the valve sleeve 124 in the form of a linear jet.

This longitudinal groove 132 is arranged offset with respect to the longitudinal groove 130 serving for pre-injection and ends at a control section 134 . When the needle valve 126 is closed, the mlJ n st part 134 is connected to the combustion chamber of the casing hole that guides the valve sleeve 124.
It is provided at the outlet on the side of the corpse and has a spacing f with respect to a valve seat edge 136 which is fixed to the casing. This distance f is slightly larger than the pre-stroke hv of the needle valve 126 in order to interrupt the injection.

In the embodiment according to FIG. 5, the annular chamber 140, which is in constant communication with the pressure chamber 138, is connected to the valve sleeve 142 and the needle valve 1.
44 , and the closing head 146 of the needle valve 144 has a spherical valve closing surface 148 . As a result, a subsequent axial guidance of the needle valve 144 within the valve sleeve 142 may optionally be omitted. In this embodiment, the main injection passage is connected to the valve sleeve 14.
2 , the wall notch 150 opens into the annular chamber 140 .

At the lower end of this wall notch 150, a control # section 151 is provided.
is formed, and this 1flJ edge part 151 is the fourth
In the closed position of the needle valve 144, the cape edge 134 in the illustrated embodiment has a spacing f slightly greater than the front stroke hv with respect to the valve seat edge 152 fixed to the housing.

[Brief explanation of the drawing]

The drawings show four υ embodiments of the fuel injection nozzle according to the present invention, and FIG. 1 is an enlarged longitudinal sectional view of the injection nozzle of the M1 embodiment, and FIG. 2 is the combustion chamber side end of the injection nozzle according to FIG. 1. FIGS. 6, 4, and 5 are longitudinal cross-sectional views showing the sections further enlarged than those in FIG. It is an enlarged longitudinal cross-sectional view. 10... Nozzle body, 12... Nozzle nut, 14.
... Nozzle holder, 18... Needle valve, 18a. 18b... Needle valve section, 20... Closing head,
22... Valve seat surface, No. 4... Closing spring, 26... Valve seat, 27... Annular disc-17, I'2B... Annular shoulder, 30... Bush, 31...・Support, 32...
・Protrusion, 34... Valve sleeve, 36... Hole, 38
... Bottom wall, 40 ... Chamber, 42 ... Insert, 44
...bottom, 46...hole, 48...wall section, 50
...pressure chamber, 52.54...passage, 56...hole,
58... Chamber, 60... Annular chamber, 62... Guide hole,
64...hole, 66...chamber, 68...hole, 70...
- Compression spring, 72... Annular collar, 74... End face edge, 16... Vertical groove, γ8... Control flank, 80...
- Control edge, 82... Control hole, 84... Annular chamber, 8
6.88... Control edge, 90... Edge groove, 94...
・Pressure chamber, 96... Nozzle body, 98... Plane part, 1
00... Needle valve, 102... Annular chamber, 104...
... Valve sleeve, 106... Vertical groove, 108... Partial annular groove, 110... Annular edge, 112... Control edge, 114... Annular collar, 115... Bottom, 116・
... Spring, 11T... Valve seat surface, 118... Closing head, 120... Hole edge, 122... Valve seat, 124...
...Valve sleeve, 126...Needle valve, 127...
・Pressure chamber, 128...partial annular groove 130.132...
- Vertical groove, 134... Control edge, 136... Valve seat edge, 138... Mocha chamber, 140... Annular chamber, 142...
...Valve sleeve, 144...Needle valve, 146...
・Close fi ”h z 148...Valve closing surface Z
150... Wall notch, 151... Control edge, 15
2... Valve seat edge, a, c, f... Spacing, b... Spacing corresponding to the previous stroke, d, θ... Cone angle, hg...
Interval corresponding to the entire stroke, hv...previous stroke, h, v work...
... Interval corresponding to the previous stroke, hV2... Interval FIG,
2

Claims (1)

[Claims] 1. A fuel injection nozzle for an internal combustion engine, comprising a needle valve movably supported within the nozzle body;
This needle valve is pressed by a closing spring against the flow of fuel onto a valve seat fixed to the casing, and is loaded by the fuel in the direction of fuel flow, and furthermore, A valve sleeve is disposed movably mounted in the body upstream of the closing head of the needle valve, the upstream end section of which projects into the fuel-filled pressure chamber and whose downstream end section extends into the fuel-filled pressure chamber. The side end edge is pressed onto the closing head of the needle valve by an additional spring element, and a wall recess is provided in the valve sleeve forming an injection channel for the bundled fuel pre-injection stream. The injection passage is controlled to open by lifting the closing head of the needle valve from the valve seat fixed to the casing at the start of the injection stroke, and is further guided from the pressure chamber to the valve opening via the valve sleeve. at least one main injection passage is provided, the main injection passage being controlled by a control edge formed in the valve sleeve, which controls the opening of this passage after a pre-injection stroke of the needle valve. In this type, a wall cutout provided in the valve sleeve (34) to form an injection opening for the pre-injection flow of fuel is inserted into a vertical passageway (76) provided on the outer circumference of the valve sleeve (34). This vertical passage (76) is formed by the valve sleeve (3).
Starting from the downstream end edge (74) of 4), the control edge (
78), and in the closed state of the needle valve (18) the control edge (78) is connected to the needle valve (18).
) is located upstream of a control edge (80) fixed to the casing at a distance corresponding to the front stroke (hv_l) of the pressure chamber (50). A fuel injection nozzle for an internal combustion engine, characterized in that the fuel injection nozzle is provided at an opening of a guide hole (36) for a valve sleeve (34). 2. A control edge (86) provided on the valve sleeve (34), which controls the main injection channel, provides a longitudinal channel (76) provided around the valve sleeve (34) as an injection opening for the fuel pre-injection flow. Claim 1, characterized in that the control edge(s) at the end of the control edge (78) are arranged such that the injection is briefly interrupted between the pre-injection phase and the main injection phase. 1. The injection nozzle according to 1. 3. A stopper (44) fixed to the casing is opposed to the valve sleeve (34), and said stopper (44)
4) is characterized in that, before the full opening stroke of the needle valve (18) is completely completed, said valve sleeve (34) is forced to move relative to the continuing movement of the needle valve (18). The injection nozzle according to claim 1 or 2. 4. An annular chamber (84) filled with fuel and forming a section of the main injection passage is formed between the valve sleeve (34) and the needle valve (18) and From claim 1, wherein a control passage (82) connecting the pressure chamber (50) and the annular chamber (84) during the main injection stroke of (18) is provided in the valve sleeve (34). 3. The injection nozzle according to any one of items 3 to 3. 5. A control edge (86) for controlling the main injection passage is formed at the control passage (82) of the valve sleeve (34), which control passage (82) is in the closed position of the needle valve (18) and During the pre-injection process, a valve sleeve (
5. The injection nozzle according to claim 4, characterized in that the injection nozzle is covered by a hole wall portion that guides the pressure chamber (50) during the main injection process. 6. Valve sleeve (34) provided for main injection
The valve sleeve (34) has a lateral injection opening (90) placed on the closing head (22) of the needle valve (18).
6. The injection nozzle according to claim 1, wherein the injection nozzle is formed by a cutout in the end edge (74) of the injection nozzle. 7. The valve sleeve (104) together with the needle valve (100) forms an annular chamber (102) filled with fuel, which is in constant communication with the pressure chamber (94) and Forming a section of the injection passage, the lower end edge (120) of the valve sleeve (104) forms a section of the needle valve (
100) controls an annular valve gear for the umbrella-shaped main fuel injection flow, and a stop (115) fixed to the casing is opposed to the valve sleeve (104). This stopper (11
5) forces the valve sleeve (104) to move relative to the continuing moving needle valve (100) towards the end of the full opening stroke of the needle valve (100), and thereby 7. Injection nozzle according to claim 1, characterized in that an annular valve gap is opened. 8. The lower end wall of the valve sleeve (104) is conically shaped, and the cone angle (a) of this conical end wall is likewise conical at the closing head (118) of the needle valve (100). The cone angle of the valve seat surface (117) formed in
The injection nozzle according to claim 7, characterized in that the injection nozzle is larger than e). 9. The main injection passage is defined by at least one longitudinal groove (132) around the valve sleeve (124), which longitudinal groove (132)
) starts at the end face facing the pressure chamber (127) and leads to a control edge (134) which, in the closed state of the needle valve (126), extends into the valve sleeve (1
24) is separated from the valve seat edge (136) formed at the combustion chamber side opening of the guide hole by an overlap amount (f),
Injection nozzle according to any one of claims 1 to 3, characterized in that this overlap amount (f) is equal to or slightly larger than the forward stroke (hv) of the needle valve (126). 10. The main injection channel is formed by at least one wall cutout (150) in the valve sleeve (142), which wall cutout (150) is connected to the valve sleeve (142) and the needle valve ( 1
The pressure chamber (13) is connected to the pressure chamber (13) via the annular chamber (140) between the
8), and when the needle valve (144) is in the closed state, the valve seat edge (152) formed at the combustion chamber side opening of the casing hole guides the valve sleeve (142).
), and this overlap amount (f) is separated from the previous stroke (h) of the needle valve (144).
4. Injection nozzle according to claim 1, characterized in that the injection nozzle is equal to or slightly larger than v).