Information
-
Patent Grant
-
6622932
-
Patent Number
6,622,932
-
Date Filed
Tuesday, October 16, 200122 years ago
-
Date Issued
Tuesday, September 23, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 239 8892
- 239 96
- 239 5333
- 239 5334
- 239 5332
- 239 5335
- 239 584
- 239 5
-
International Classifications
-
Abstract
Within an injector housing, a nozzle needle comprising a nozzle needle shaft is accommodated in a first guide boring in a longitudinally displaceable manner. A nozzle prechamber which is arranged in front of the nozzle needle shaft and which is situated on the fore-part of the first guide boring is supplied with fuel via a high pressure channel. A control valve permits a control chamber, which is coupled to the nozzle needle and which is subjected to the action of highly pressurized fuel, to be relieved from pressure by opening the nozzle needle. According to a second embodiment, a spring chamber is configured as a high-pressure chamber on the rear side of the first guide boring that guides the nozzle needle shaft. The spring chamber is separate from the control chamber and contains a readjusting spring that impinges upon the nozzle needle in a direction of closure. This configuration prevents fuel exiting the nozzle prechamber from overflowing over the guide boring which guides the nozzle needle.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a fuel injector for injecting fuel provided at a high pressure into the combustion space of an internal-combustion engine.
Such a known fuel injector comprises an injector housing and a nozzle needle which has a nozzle needle shaft, which is longitudinally displaceably disposed in a first guide bore constructed in the injector housing, and a nozzle needle point interacting in the sense of an opening and closing of a valve opening cross-section with a valve seat constructed in the forward end of the injector housing. For supplying highly pressurized fuel to be injected, a high-pressure duct is provided. On the face side of the first guide bore, a nozzle antechamber is disposed in front of the nozzle needle shaft, which antechamber is acted upon at a high pressure by the fuel to be injected which is supplied by way of the high-pressure duct. A control space acted upon by highly pressurized fuel is coupled with the nozzle needle, which control space can be relieved from pressure by a control valve in the sense of an opening of the nozzle needle. At the rearward side of the first guide bore, a space is arranged which receives fuel flowing from the nozzle antechamber by way of the first guide bore.
Such a fuel injector has the disadvantage that considerable leakage occurs between the nozzle antechamber and the space arranged on the rearward side of the first guide bore as well as between the control space and this space, which leakage may be in the range of up to 20 or 30% of the maximal injection quantity.
It is an object of the invention to construct a fuel injector of the initially mentioned type such that this leakage is avoided.
This object is achieved by way of a fuel injector having the space arranged on the rearward side of the first guide bore is a high-pressure space acted upon by a highly pressurized fuel.
Advantageous further developments of the fuel injector according to the invention are characterized in the preferred embodiments.
The fuel injector according to the invention is provided for injecting highly pressurized fuel into the combustion space of an internal-combustion engine. The fuel injector comprises an injector housing and a nozzle needle which has a nozzle needle shaft, which is longitudinally displaceably disposed in a first guide bore constructed in the injector housing, and a nozzle needle point interacting in the sense of an opening and closing of a valve opening cross-section with a valve seat constructed in the forward end of the injector housing. For supplying highly pressurized fuel to be injected, a high-pressure duct is used. On the face side of the first guide bore, a nozzle antechamber is disposed in front of the nozzle needle shaft, which antechamber is acted upon at a high pressure by the fuel to be injected which is supplied by the high-pressure duct. A control space acted upon by highly pressurized fuel is coupled with the nozzle needle, which control space can be relieved from pressure by a control valve in the sense of an opening of the nozzle needle. At the rearward side of the first guide bore, a space is arranged which receives fuel flowing from the nozzle antechamber by way of the first guide bore or from the control space. According to the invention, the space arranged on the rearward side of the first guide bore is a high-pressure space acted upon by a highly pressurized fuel.
The significant advantage of the fuel injector according to the invention is the fact that no space which is at a low pressure level is situated on the rearward side of the first guide bore guiding the nozzle needle, so that no leakage can occur by way of this space.
According to an aspect of the invention, the high-pressure space constructed on the rearward side of the first guide bore is formed by the control space. This results in the advantage that, as a result of the pressure existing in the control space, a flowing over of fuel by way of the first guide bore is not possible. Another advantage is the fact that, because of the direct action upon the nozzle needle by the pressure situated in the control space, a very rapid response behavior of the fuel injector is achieved. Since there is no low-pressure space adjoining the control space, a leakage from the control space cannot take place.
According to a further development of the invention, the control space forming the rearward-side high-pressure space contains a restoring spring acting upon the nozzle needle in the closing direction.
The restoring spring is advantageously formed by a cup spring arrangement. Preferably, it is provided that the restoring spring is supported on one end by a first abutment provided on the rearward side of the nozzle needle shaft and is supported on the other end by a second abutment constructed on the rearward side of the control space.
According to an advantageous embodiment of the invention, the control space forming the rearward-side high-pressure space is formed by a bore extending in the longitudinal direction of the injector housing and, on its rearward side, is bounded by a valve body of the control valve inserted into this bore.
The control space forming the rearward-side high-pressure space is preferably connected by way of a throttle duct with the high-pressure duct carrying the fuel to be injected.
According to a second aspect of the invention, the rearward high-pressure space is formed by a spring space containing the restoring spring acting upon the nozzle needle in the closing direction. In this respect, it is advantageous that the restoring spring can be optimally dimensioned, while simultaneously the control space can be constructed to be very small, which is advantageous for the response behavior of the fuel injector.
The spring space is preferably connected by way of a fluidic connection with the high-pressure duct carrying the fuel to be injected.
According to a particularly advantageous embodiment of this variant of the fuel injector according to the invention, a second guide bore is constructed at the rearward side of the spring space forming the high-pressure space, which second guide bore extends coaxially to the first guide bore carrying the nozzle needle shaft and in which a guiding piston is displaceably in the longitudinal direction disposed, which guiding piston is coupled by way of a needle stilt with the nozzle needle, the guiding piston bounding the spring space on its rearward side.
The control space is preferably constructed on the rearward side of the guiding piston, in which case the fuel which is present at a high pressure in the spring space and the restoring spring act upon the nozzle needle shaft in the sense of a closing of the nozzle needle and, when the control space is relieved from pressure, the nozzle needle is relieved by the control valve by the guiding piston in the sense of an opening.
The first guiding bore guiding the nozzle needle shaft preferably has a diameter D
1
. The spring space is formed by a third bore coaxial to the first guide bore, the diameter D
2
of the third bore being larger than the diameter D
1
of the first guide bore. The control space is formed by the second guide bore with a diameter D
1
′ which is coaxial to the first guide bore and the spring space.
According to a preferred embodiment, it is provided that the diameters D
1
, D
1
′ and D
2
are mutually coordinated such that the needle stilt during the opening as well as during the closing of the nozzle needle is only stressed with respect to tension. As a result, a buckling or a one-sided contact of the nozzle needle stilt, which could result in a jamming, will be avoided.
According to a preferred embodiment, the first guide bore and the second guide bore have the same diameter D
1
. The resulting advantage is a simplification during the manufacturing of the fuel injector.
According to a preferred embodiment, the restoring spring is supported on one end by a first abutment provided on the rearward side of the nozzle needle shaft and is supported on the other end by a second abutment constructed on the rearward side of the spring space.
The control space preferably has a significantly smaller volume than the spring space.
According to an advantageous further development of the fuel injector according to the invention, it is provided that the injector housing contains on the rearward-side end an individual storage device for supplying highly pressurized fuel, which individual storage device is connected with the high-pressure duct carrying the fuel to be injected. Such an individual storage device can be implemented particularly in the case of the fuel injector according to the first embodiment of the invention, in which the rearward-side high-pressure space is formed by the control space because a significant amount of length is saved in this embodiment and can be utilized for the individual storage device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
shows a slightly schematic longitudinal sectional view of a fuel injector according to a first embodiment of the invention having the control space;
FIG. 2
a slightly schematic longitudinal sectional view of a fuel injector according to a second embodiment of the invention having a spring space and a restoring spring; and
FIG. 3
shows a slightly schematic longitudinal sectional view of a fuel injector according to the state of the art.
DETAILED DESCRIPTION OF THE DRAWINGS
First, by way of
FIG. 3
, a fuel injector will be described for injecting highly pressurized fuel into the combustion space of an internal-combustion engine, as known according to the state of the art. The fuel injector, which as a whole has the reference number
300
, comprises an injector housing
301
, in which a nozzle needle
303
with a nozzle needle shaft
304
is longitudinally displaceably disposed in a first guide bore
302
constructed in the injector housing
301
. The nozzle needle
303
has a nozzle needle point
305
which interacts in the sense of an opening and closing of a valve opening cross-section with a valve seat
306
constructed in the forward end of the injector housing
301
, the valve opening cross-section being provided between the needle point
305
and the valve seat
306
. A high-pressure duct
307
is provided for feeding highly pressurized fuel to be injected which is supplied by way of a pressure connection
329
. The fuel is held at a high pressure in an oil-elastic pressure storage device (common rail), into which it is supplied by way of a high-pressure pump from a fuel supply (not shown in the figure).
On the front face of the first guide bore
302
, a nozzle antechamber
308
is disposed in front of the nozzle needle shaft
304
and provided in the injector housing
301
, which nozzle antechamber
308
is acted upon by the highly pressurized fuel to be injected which is supplied by way of the high-pressure duct
307
. A control space
309
which by way of a throttle duct
314
connected with the high-pressure duct
307
is acted upon by highly pressurized fuel, is, by way of a needle stilt
322
, which is displaceably in the longitudinal direction of the fuel injector
300
in a guiding sleeve
330
arranged in the injector housing
301
, coupled with the nozzle needle
303
. On the rearward side of the control space
309
, a control valve
310
is provided which is formed by a valve body
312
and a closing body
313
.
With respect to its operation, the closing body
313
of the control valve
310
is coupled with a solenoid
326
, by which the control valve
310
is opened and closed. When the control valve
310
is closed, the nozzle needle
303
is kept closed by way of the needle stilt
322
by the high pressure present in the control space
309
. While during the opening of the control valve
310
, the control space
309
can be relieved from pressure in the sense of an opening of the nozzle needle
303
by way of the needle stilt
322
.
On the rearward side of the first guide bore
302
guiding the nozzle needle
303
, a low-pressure space
331
is constructed partially surrounding the needle stilt
322
between the nozzle needle
303
and the control space
309
. By way of this low-pressure space
331
, fuel flowing over from the nozzle antechamber
308
by way of the first guide bore
302
and from the control space
309
by way of the guide sleeve
330
is discharged as a leakage quantity. Surrounding the forward end of the needle stilt
322
, a restoring spring
316
for closing the nozzle needle
303
is provided in the low-pressure space
331
between a first abutment
320
provided on the rearward side of the nozzle needle
303
and a second abutment
321
provided on the injector housing
301
.
When the control space
309
is relieved from pressure, the nozzle needle
303
is opened by way of the control valve
310
by the fuel pressure applied in the nozzle antechamber
308
to the nozzle needle shaft
304
. The fuel quantity closing off by way of the control valve
310
when the control space
309
is relieved from pressure, is discharged jointly with the fuel quantity from the low-pressure space
331
by way of a leakage duct
332
.
A first embodiment of a fuel injector according to the invention for injecting highly pressurized fuel into the combustion space of an internal-combustion engine will now be described by way of FIG.
1
. Similar to the known fuel injector, in the case of the fuel injector illustrated here and marked with the reference number
100
in an injector housing
101
, a nozzle needle
103
is longitudinally displaceably disposed with a nozzle needle shaft
104
in a first guide bore
102
constructed in the injector housing
101
. On its forward end, the nozzle needle
103
has a nozzle needle point
105
which interacts in the sense of an opening and closing of a valve opening cross-section with a valve seat
106
constructed in the forward end of the injector housing
101
, which valve opening cross-section is provided between the nozzle needle point
105
and the valve seat
106
. For feeding highly pressurized fuel to be injected, a high-pressure duct
107
is constructed in the injector housing
101
. The fuel to be injected is supplied by way of a pressure connection
129
by an oil-elastic storage device (common rail) to which the fuel is delivered from a fuel supply by way of a high-pressure pump (not shown).
On the forward side of the first guide bore
102
, a nozzle antechamber
108
is disposed in front of the nozzle needle shaft
104
, which nozzle antechamber
108
is acted upon by highly pressurized fuel to be injected which is supplied by way of the high-pressure duct
107
. On the rearward side of the nozzle needle
103
, a control space
109
is constructed in the injector housing
101
and adjoins the first guide bore
102
and by way of a throttle duct
114
connected with the high-pressure duct
107
is acted upon by highly pressurized fuel. The control space
109
is formed by a control space bore
111
in the injector housing
101
and is bounded on its rearward side by a valve body
112
of a control valve
110
inserted into the control space bore
111
. With respect to the operation, a closing body
113
of the control valve
110
is coupled with a solenoid
126
provided in the rearward end of the injector housing
101
. Furthermore, a restoring spring
116
is arranged in the control space
109
, which restoring spring
116
is supported between a first abutment
120
provided on the rearward side of the nozzle needle shaft
104
and a second abutment
121
formed by the forward side of the valve body
112
of the control valve
110
.
When the control valve
110
is closed, the nozzle needle
103
is kept closed under the effect of the restoring spring
116
and of the highly pressurized fuel in the control space
109
. When the control space
109
is relieved from pressure by way of the control valve
110
, the nozzle needle
103
is opened under the effect of the highly pressurized fuel present in the nozzle antechamber
108
, in which case the fuel flowing off from the control space
109
by way of the control valve
110
is discharged by way of the leakage duct
132
.
The injector housing
101
may contain on the rearward side end an individual storage device
127
for supplying highly pressurized fuel. The individual storage device
127
can connect to the high-pressure duct
107
.
As shown by a comparison with the fuel injector according to the prior art illustrated in
FIG. 3
, no low-pressure space is situated on the rearward side of the nozzle needle
103
, by way of which low-pressure space a leakage quantity could occur which flows over from the nozzle antechamber
108
through the first guide bore
102
. The highly pressurized fuel present in the control space
109
prevents such a flowing-over of fuel from the nozzle antechamber
108
by way of the first guide bore
102
. In the illustrated embodiment, the restoring spring
116
is formed by a cup spring arrangement.
FIG. 2
illustrates a second embodiment of a fuel injector according to the invention for injecting highly pressurized fuel into the combustion space of an internal-combustion engine. The fuel injector, which as a whole has the reference number
200
, comprises an injector housing
201
, in which a nozzle needle
203
with a nozzle needle shaft
204
is longitudinally displaceably disposed in a first guide bore
202
constructed in the injector housing
201
. The nozzle needle
203
has a nozzle needle point
205
which interacts in the sense of an opening and closing of a valve opening cross-section with a valve seat
206
constructed in the forward end of the injector housing
201
, the valve opening cross-section being provided between the nozzle needle point
205
and the valve seat
206
.
A high-pressure duct
207
is constructed in the injector housing
201
for feeding highly pressurized fuel to be injected and is connected with a pressure connection
229
to which the fuel to be injected is supplied by an oil-elastic pressure storage device (common rail), into which it is supplied by way of a high-pressure pump from a fuel supply (not shown).
On the front face of the first guide bore
202
, a nozzle antechamber
208
is constructed in the injector housing
201
, which nozzle antechamber
208
is acted upon at a high pressure by the fuel to be injected which is supplied by way of the high-pressure duct
207
.
A control space
209
, having a bore
211
, is constructed in the rearward part of the injector housing
201
and by way of a throttle duct
214
connected with the high-pressure duct
207
is acted upon by highly pressurized fuel and can be relieved from pressure by way of a control valve
210
.
On the rearward side of the first guide bore
202
, a high-pressure space is provided between the nozzle needle
203
and the control space
209
, which high-pressure space is formed by a spring space
215
containing the restoring spring
216
acting upon the nozzle needle
203
in the closing direction. The spring space
215
is separated from the control space
209
by a guiding piston
219
longitudinally displaceably disposed in a second guide bore
218
constructed coaxially to the first guide bore
202
. The guiding piston
219
is coupled by way of a needle stilt
222
with the rear side of the nozzle needle
203
, whereby a coupling of the control space
209
is established with the nozzle needle
203
. The guiding piston
219
therefore bounds the spring space
215
on its rearward side. The spring space
215
is connected by way of a fluidic connection
217
with the high-pressure duct
207
carrying the fuel to be injected, so that the same high pressure exists in the interior of the spring space
215
as in the high-pressure duct
207
and therefore also in the nozzle antechamber
208
. Thus, a flowing-over of fuel from the nozzle antechamber
208
by way of the first guide bore
202
into the space, specifically the spring space
215
, situated on the rearward side of the nozzle needle
203
cannot take place.
Together with the force of the restoring spring
216
, the fuel present in the spring space
215
at a high pressure acts upon the nozzle needle shaft
204
in the sense of a closing of the nozzle needle
203
, while, when the control space
209
is relieved from pressure by way of the control valve
210
, the nozzle needle
203
is relieved by the guiding piston
219
by way of the needle stilt
222
in the sense of an opening.
The control valve
210
contains a valve body
212
and a closing body
213
which, with respect to the operation, is coupled with a solenoid
226
controlling the operation of the fuel injector. The restoring spring
216
arranged in the spring space
215
is supported on one end by a first abutment
220
provided on the rearward side of the nozzle needle shaft
204
and is supported on the other end by a second abutment
221
constructed on the rearward side of the spring space
215
.
The first guide bore
202
guiding the nozzle needle shaft
204
has a diameter D
1
. A third bore
228
, which forms the spring space
215
and is coaxial to the first guide bore
202
, has a diameter D
2
which is larger than the diameter D
1
of the first guide bore
202
. The second guide bore
218
, which is coaxial to the first guide bore
202
and therefore simultaneously to the third bore
228
forming the spring space
215
and which, in its rearward part also forms the control space
209
, has a diameter D
1
′ which, in the illustrated embodiment, is equal to the diameter D
1
of the first guide bore
202
; that is D
1
′=D
1
. The diameters D
1
, D
1
′ and D
2
,—in the present embodiment, therefore only the two diameters D
1
and D
2
—are mutually coordinated such that, during the opening and during the closing of the nozzle needle
203
, the needle stilt
222
is stressed only with respect to tension. As a result, a buckling or a one-sided contacting of the needle stilt
222
, which may lead to a jamming, is avoided.
The control space
209
has a significantly smaller volume than the spring space
215
, whereby the response behavior of the fuel injector is improved.
Claims
- 1. A method of making a fuel injector for injecting high-pressure fuel into a combustion space of an internal combustion engine, comprising:providing an injector housing, longitudinally displaceably disposing a nozzle needle shaft of a nozzle needle in a first guide bore of the injector housing, said nozzle needle including a nozzle needle point which operatively interacts with a valve seat in a forward end of the injector housing, providing a high-pressure duct for operatively supplying the high-pressure fuel to be injected, disposing a nozzle antechamber on a front face side of the first guide bore in front of the nozzle needle shaft, coupling a control space which is operatively acted upon by the high-pressure fuel with the nozzle needle, connecting a control valve to the control space so that the control valve can operatively release pressure from the control space, and arranging a space on a rearward side of the first guide bore so that said space operatively receives fuel flowing over from the nozzle antechamber via the first guide bore or the control space, wherein the space on the rearward side of the first guide bore is a high-pressure space operatively acted upon by the high-pressure fuel.
- 2. A method according to claim 1, wherein the high-pressure space on the rearward side of the first guide bore is formed by the control space.
- 3. A method according to claim 1, wherein the high-pressure space is formed by a spring space and is separate from the control space, said high-pressure space containing a restoring spring operatively acting upon the nozzle needle in a closing direction.
- 4. A method according to claim 1, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
- 5. A method of operating a fuel injector for an internal combustion engine, comprising:providing an injector housing an a nozzle needle which has a nozzle needle shaft longitudinally diplaceably disposed in a first guide bore in the injector housing and a nozzle needle point, supplying highly pressurized fuel to be injected via a high-pressure duct, applying the highly pressurized fuel to a nozzle antechamber disposed on a front face side of the first guide bore in front of the nozzle needle shaft, applying the highly pressurized fuel to a control space coupled with the nozzle needle, applying the highly pressurized fuel to a space arranged on a rearward side of the first guide bore, and relieving pressure in the control space via a control valve to thereby open the nozzle needle by unseating the nozzle needle point from a valve seat at a forward end of the injector housing, wherein said space receives fuel flowing over from the nozzle antechamber via the first guide bore or from the control space.
- 6. A fuel injector for injecting highly pressurized fuel into a combustion space of an internal combustion engine, comprising:an injector housing, a nozzle needle which has a nozzle needle shaft longitudinally displaceably disposed in a first guide bore constructed in the injector housing and a nozzle needle point which interacts with a valve seat constructed in a forward end of the injector housing, a high-pressure duct for supplying the highly pressurized fuel to be injected, a nozzle antechamber disposed on a front face side of the first guide bore in front of the nozzle needle shaft and acted upon at high pressure by the fuel to be injected and supplied by way of the high-pressure duct, a control space which is coupled with the nozzle needle and acted upon by the highly pressurized fuel, said control space being relievable from pressure by way of a control valve which causes an opening of the nozzle needle, and a space arranged on a rearward side of the first guide bore, said space receiving fuel flowing over from the nozzle antechamber by way of the first guide bore or from the control space, wherein the space arranged on the rearward side of the first guide bore is a high-pressure space acted upon by the highly pressurized fuel.
- 7. A fuel injector according to claim 6, wherein the high-pressure space constructed on the rearward side of the first guide bore is formed by the control space.
- 8. A fuel injector according to claim 7, wherein the control space forming the rearward-side high-pressure space contains a restoring spring acting upon the nozzle needle in a closing direction.
- 9. A fuel injector according to claim 8, wherein the restoring spring is formed by a cup spring arrangement.
- 10. A fuel injector according to claim 9, wherein the restoring spring is supported on one end by a first abutment provided on a rearward side of the nozzle needle shaft and is supported on another end by a second abutment constructed on a rearward side of the control space.
- 11. A fuel injector according to claim 7, wherein the control space forming the rearward high-pressure space is formed by a control space bore extending in a longitudinal direction of the injector housing and, on a rearward side, is bounded by a valve body of the control valve inserted into said control space bore.
- 12. A fuel injector according to claim 8, wherein the control space forming the rearward high-pressure space is formed by a control space bore extending in a longitudinal direction of the injector housing and, on a rearward side, is bounded by a valve body of the control valve inserted into said control space bore.
- 13. A fuel injector according to claim 9, wherein the control space forming the rearward high-pressure space is formed by a control space bore extending in a longitudinal direction of the injector housing and, on a rearward side, is bounded by a valve body of the control valve inserted into said control space bore.
- 14. A fuel injector according to claim 10, wherein the control space forming the rearward high-pressure space is formed by a control space bore extending in a longitudinal direction of the injector housing and, on a rearward side, is bounded by a valve body of the control valve inserted into said control space bore.
- 15. A fuel injector according to claim 7, wherein the control space forming the rearward-side high-pressure space is connected by way of a throttle duct with the high-pressure duct guiding the fuel to be injected.
- 16. A fuel injector according to claim 8, wherein the control space forming the rearward-side high-pressure space is connected by way of a throttle duct with the high-pressure duct guiding the fuel to be injected.
- 17. A fuel injector according to claim 9, wherein the control space forming the rearward-side high-pressure space is connected by way of a throttle duct with the high-pressure duct guiding the fuel to be injected.
- 18. A fuel injector according to claim 10, wherein the control space forming the rearward-side high-pressure space is connected by way of a throttle duct with the high-pressure duct guiding the fuel to be injected.
- 19. A fuel injector according to claim 11, wherein the control space forming the rearward-side high-pressure space is connected by way of a throttle duct with the high-pressure duct guiding the fuel to be injected.
- 20. A fuel injector according to claim 6, wherein the rearward-side high-pressure space is formed by a spring space which is separate from the control space and contains a restoring spring acting upon the nozzle needle in a closing direction.
- 21. A fuel injector according to claim 20, wherein the spring space is connected by way of a fluidic connection with the high-pressure duct guiding the fuel to be injected.
- 22. A fuel injector according to claim 20, wherein a second guide bore is constructed on a rearward side of the spring space forming the high-pressure space, which said second guide bore extends coaxial to the first guide bore guiding the nozzle needle shaft, and in which said second guide bore, a guiding piston, which is coupled by way of a needle stilt with the nozzle needle, is longitudinally displaceably disposed, said guiding piston bounding the spring space on said rearward side.
- 23. A fuel injector according to claim 21, wherein a second guide bore is constructed on a rearward side of the spring space forming the high-pressure space, which said second guide bore extends coaxial to the first guide bore guiding the nozzle needle shaft, and in which said second guide bore, a guiding piston, which is coupled by way of a needle stilt with the nozzle needle, is longitudinally displaceably disposed, said guiding piston bounding the spring space on said rearward side.
- 24. A fuel injector according to claim 22,wherein the control space is constructed on a rearward side of the guiding piston, the fuel being situated at a high pressure in the spring space and the restoring spring acting upon the nozzle needle shaft in a sense of a closing of the nozzle needle, and wherein the nozzle needle, when the control space is relieved from pressure by way of the control valve, is relieved by the guiding piston by way of the needle stilt in a sense of an opening.
- 25. A fuel injector according to claim 24, wherein the first guide bore guiding the nozzle needle shaft has a diameter D1, the spring space is formed by a third bore coaxial to the first guide bore, a diameter D2 of the third bore being larger than the diameter D1 of the first guide bore, and the control space is formed by the second guide bore which is coaxial to the first guide bore and the spring space and has a diameter D1′.
- 26. A fuel injector according to claim 25, wherein the diameters D1, D1′ and D2 are mutually coordinated such that the needle stilt is only stressed with respect to tension during the opening as well as during the closing of the nozzle needle.
- 27. A fuel injector according to claim 22, wherein the first guide bore and the second guide bore have the same diameter.
- 28. A fuel injector according to claim 24, wherein the first guide bore and the second guide bore have the same diameter.
- 29. A fuel injector according to claim 25, wherein the first guide bore and the second guide bore have the same diameter.
- 30. A fuel injector according to claim 26, wherein the first guide bore and the second guide bore have the same diameter.
- 31. A fuel injector according to claim 20, wherein the restoring spring is supported at one end by a first abutment provided on the rearward side of the nozzle needle shaft and is supported at the other end by a second abutment constructed on the rearward side of the spring space.
- 32. A fuel injector according to claim 22, wherein the restoring spring is supported at one end by a first abutment provided on the rearward side of the nozzle needle shaft and is supported at the other end by a second abutment constructed on the rearward side of the spring space.
- 33. A fuel injector according to claim 26, wherein the restoring spring is supported at one end by a first abutment provided on the rearward side of the nozzle needle shaft and is supported at the other end by a second abutment constructed on the rearward side of the spring space.
- 34. A fuel injector according to claim 27, wherein the restoring spring is supported at one end by a first abutment provided on the rearward side of the nozzle needle shaft and is supported at the other end by a second abutment constructed on the rearward side of the spring space.
- 35. A fuel injector according to claim 24, wherein the control space has a significantly smaller volume than the spring space.
- 36. A fuel injector according to claim 25, wherein the control space has a significantly smaller volume than the spring space.
- 37. A fuel injector according to claim 26, wherein the control space has a significantly smaller volume than the spring space.
- 38. A fuel injector according to claim 27, wherein the control space has a significantly smaller volume than the spring space.
- 39. A fuel injector according to claim 31, wherein the control space has a significantly smaller volume than the spring space.
- 40. A fuel injector according to claim 6, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
- 41. A fuel injector according to claim 7, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
- 42. A fuel injector according to claim 8, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
- 43. A fuel injector according to claim 15, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
- 44. A fuel injector according to claim 20, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
- 45. A fuel injector according to claim 26, wherein the injector housing contains at a rearward end an individual storage device, which is connected with the high-pressure duct guiding the fuel to be injected, for supplying highly pressurized fuel.
Priority Claims (1)
Number |
Date |
Country |
Kind |
199 17 190 |
Apr 1999 |
DE |
|
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/EP00/03319 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO00/63550 |
10/26/2000 |
WO |
A |
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5692683 |
Mathis |
Dec 1997 |
A |
Foreign Referenced Citations (4)
Number |
Date |
Country |
4332837 |
Jul 1994 |
DE |
582993 |
Feb 1994 |
EP |
639710 |
Feb 1995 |
EP |
844383 |
May 1998 |
EP |