US20050089426A1 - Injection nozzle - Google Patents
Injection nozzle Download PDFInfo
- Publication number
- US20050089426A1 US20050089426A1 US10/945,990 US94599004A US2005089426A1 US 20050089426 A1 US20050089426 A1 US 20050089426A1 US 94599004 A US94599004 A US 94599004A US 2005089426 A1 US2005089426 A1 US 2005089426A1
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- US
- United States
- Prior art keywords
- control chamber
- nozzle
- nozzle needle
- coupling path
- needle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000002347 injection Methods 0.000 title claims abstract description 86
- 239000007924 injection Substances 0.000 title claims abstract description 86
- 230000008878 coupling Effects 0.000 claims abstract description 80
- 238000010168 coupling process Methods 0.000 claims abstract description 80
- 238000005859 coupling reaction Methods 0.000 claims abstract description 80
- 239000000446 fuel Substances 0.000 claims abstract description 39
- 238000002485 combustion reaction Methods 0.000 claims abstract description 5
- 238000004891 communication Methods 0.000 claims description 9
- 230000000903 blocking effect Effects 0.000 claims description 4
- 230000000977 initiatory effect Effects 0.000 claims 3
- 230000005540 biological transmission Effects 0.000 description 9
- 239000012530 fluid Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
- F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
- F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
- F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
- F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
- F02M45/08—Injectors peculiar thereto
- F02M45/086—Having more than one injection-valve controlling discharge orifices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
- F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
- F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/46—Valves, e.g. injectors, with concentric valve bodies
Definitions
- the invention relates to an improved fuel injection nozzle for an internal combustion engine.
- One injection nozzle known for instance from German Patent Disclosure DE 100 58 153 A1 has a needle body which has at least one first injection port and at least one second injection port and includes both a first nozzle needle and a second nozzle needle.
- the first nozzle needle is embodied as a hollow needle, and the second nozzle needle is disposed coaxially to and in the first nozzle needle. With the aid of the first nozzle needle, the injection of fuel through the at least one first injection port can be controlled, while the second nozzle needle serves to control the injection of fuel through the at least one second injection port.
- the needle body includes a first control chamber, in which a first control face is disposed.
- This first control face is drive-coupled to the second nozzle needle and is oriented such that a pressure prevailing in the first control chamber generates pressure forces at the first control face that introduce closing forces into the second nozzle needle.
- Communicating with this first control chamber is a control line, with which the pressure in the first control chamber can be controlled.
- the needle body furthermore includes a pressure chamber to which a fuel supply line is connected.
- the first nozzle needle has at least one pressure step, which when the pressure chamber is subjected to pressure introduces opening forces into the first nozzle needle. If a low pressure prevails in the fuel supply line, then closing forces, generated by a suitable closing spring, are generated predominantly at the first nozzle needle.
- a high pressure is generated in the fuel supply line and, in the first nozzle needle by way of its pressure step, this high pressure generates sufficiently high opening forces.
- the first nozzle needle is thus directly controlled by the pressure applied to its pressure step so that the first nozzle needle is pressure-controlled.
- the second nozzle needle is likewise equipped with a pressure step, but only when the first nozzle needle is opened is it acted upon by the high pressure and is capable of generating forces operative in the opening direction of the second nozzle needle.
- a suitable high pressure prevails in the first control chamber, the closing forces predominate in the second nozzle needle. If with the first nozzle needle opened, the pressure in the first control chamber is lowered via the control line, then the opening forces predominate at the second nozzle needle.
- the second nozzle needle is not controlled directly by the pressure applied to its pressure step but rather indirectly via the pressure in the first control chamber. Accordingly, the second nozzle needle in this case is servo-controlled.
- the second nozzle needle To enable the second nozzle needle to open quickly, the pressure in the first control chamber drops correspondingly fast. As a result, the second nozzle needle is given a relatively high stroke speed. At certain engine operating points, it is necessary for the injection to be terminated again only briefly after the opening of the second nozzle needle. This can result in configurations in which the second nozzle needle closes too early, for instance if because of its high stroke speed it bounces back from a stop that defines the maximum opening stroke of the second nozzle needle. To attain optimal emissions and power values for the engine, however, it must be possible to predetermine the opening and closing instants of the injection nozzle as exactly as possible.
- the injection nozzle of the invention has the advantage over the prior art that upon opening of the second nozzle needle, a lesser stroke speed is established for that nozzle needle, so that no bouncing, or only reduced bouncing, of the second nozzle needle occurs.
- the end of injection for the fuel injection through the at least one second injection port, or through all the injection ports can be predetermined with greater accuracy.
- the first control chamber is connected for communication to a suitable pressure source directly or indirectly via a first coupling path.
- the pressure in the control chamber cannot drop so sharply, since hydraulic fluid, in particular fuel, permanently continues to flow in via the first coupling path.
- both nozzle needles are servo-controlled.
- a second control face is provided, which is embodied on the first nozzle needle or is drive-coupled to it and which is disposed in the first control chamber, where it can be acted upon by a pressure acting in the closing direction of the first nozzle needle.
- the pressure in the first control chamber thus controls both the first nozzle needle and the second nozzle needle.
- a second coupling path has particular significance here; it likewise connects the first control chamber to the pressure source for communication and is controlled as a function of the stroke of the first nozzle needle.
- the control of the second coupling path is designed such that beginning at the closing position of the first nozzle needle, the second coupling path is open up to a predetermined prestroke of the first nozzle needle and is blocked beyond a stroke of the first nozzle needle that goes beyond the prestroke.
- the first control chamber is supplied with replenishing hydraulic fluid upon the opening of the first nozzle needle, until the prestroke is attained, both through the first coupling path and through the second coupling path. Beyond the prestroke, or in other words when the second coupling path is blocked, the supply of hydraulic fluid to the first control chamber is then effected only via the first coupling path.
- the pressure in the first control chamber upon opening of the control line that communicates with the first control chamber, initially drops to a first value and then, when the prestroke is reached, drops to a second value that is less than the first.
- These pressure values can be designed such that at the first pressure value, only the first nozzle needle opens, while at the second pressure value, the second nozzle needle opens as well. The expense for achieving the servo control of the two nozzle needles is comparatively slight as a result.
- FIGURE shows a longitudinal section, greatly simplified, through a basic illustration of a preferred exemplary embodiment of the injection nozzle of the invention.
- an injection nozzle 1 of the invention has a needle body 2 , which protrudes with a nozzle tip 3 into a combustion chamber 4 or a mixture-forming chamber 4 of an internal combustion engine, in particular a Diesel engine.
- the needle body 2 includes at least one first injection port 5 and at least one second injection port 6 .
- a plurality of first injection ports 5 are provided, in particular arranged in a ring.
- a plurality of second injection ports 6 may be provided, also expediently arranged in a ring.
- a first nozzle needle 7 is supported with an adjustable stroke.
- the needle body 2 includes a first needle guide 8 , which has a first guide cross section 9 .
- the first nozzle needle 7 is seated in a first seat 10 , which has a first seat cross section 11 .
- the first nozzle needle 7 is equipped with at least one pressure step 12 , which is oriented toward the injection ports 5 , 6 . This pressure step 12 is embodied by providing that the first guide cross section 9 is larger than the first seat cross section 11 .
- the first nozzle needle 7 is braced on a transmission body 13 , which in this case has a disklike or sleevelike shape.
- the transmission body 13 is in turn braced, on a side remote from the nozzle needle 7 , on a coupling sleeve 14 .
- the first nozzle needle 7 , the transmission body 13 , and the coupling sleeve 14 here form a first needle combination 15 , which is supported as a unit, with an adjustable stroke, in the needle body 2 .
- the individual components 7 , 13 , 14 of the first needle combination 15 can rest quasi-loosely against one another. It is equally possible for the individual components 7 , 13 , 14 to be secured to one another. It is equally possible for at least two of the components, such as the transmission body 13 and the coupling sleeve 14 , to be combined into a one-piece component.
- the first nozzle needle 7 is assigned a restoring spring 16 , by way of which the first needle combination 15 is braced on the needle body 2 .
- the restoring spring 16 may introduce a restoring force, operative in the closing direction represented by an arrow 17 , which can be introduced into the first nozzle needle 7 .
- the opening direction is correspondingly represented by an arrow 18 .
- the restoring spring 16 is braced here on the transmission body 13 , which thus transmits the restoring force to the first nozzle needle 7 .
- the first nozzle needle 7 is embodied as a hollow needle and serves in its interior to support a second nozzle needle 19 , which is coaxial with the first nozzle needle 7 .
- the first nozzle needle 7 includes a needle guide 20 , which has a second guide cross section 21 .
- the second nozzle needle 19 in the closing direction shown here, is seated in a second seat 22 , which is disposed between the at least one first injection port 5 and the at least one second injection port 6 and has a second seat cross section 23 .
- this pressure step 24 is embodied by providing that the second seat cross section 23 is smaller than the second guide cross section 21 .
- the second nozzle needle 19 is braced on a transmission bolt 25 , which in turn is braced on a coupling rod 26 .
- the second nozzle needle 19 , the transmission bolt 25 , and the coupling rod 26 again form a common, adjustable-stroke unit, that is, a second needle combination 27 . If in conventional operation of the injection nozzle 1 , solely pressure forces occur inside the second needle combination 27 , then once again the members of the second needle combination 27 , that is, the second nozzle needle 19 , the transmission bolt 25 and the coupling rod 26 , may rest loosely against one another. Once again, it may be expedient for at least two of the components 19 , 25 , 26 to be secured against one another or to be produced as a one-piece component.
- the needle body 2 furthermore includes a first control chamber 28 , in which both a first control face 29 and a second control face 30 are disposed.
- the first control face 29 is a component of the second needle combination 27 and is embodied here on the coupling rod 26 .
- the first control face 29 may also be embodied directly on the second nozzle needle 19 .
- the first control face 29 is oriented away from the injection ports 5 , 6 , so that pressure exerted on the first control face 29 transmits a force acting in the closing direction 17 on the second needle combination 27 , which force is thus introduced into the second nozzle needle 19 .
- the second control face 30 is embodied on the first needle combination 15 and is likewise oriented away from the injection ports 5 , 6 . Accordingly, pressure exerted on the second control face 30 leads to the introduction of a force effected in the closing direction 17 into the first needle combination 15 and thus into the first nozzle needle 7 .
- the first control chamber 28 communicates with a control line 31 , with the aid of which the pressure in the first control chamber 28 can be controlled.
- this control line 31 is embodied as an outlet line, and will therefore henceforth be called the outlet line 31 .
- the outlet line 31 here contains a control valve 32 , which has two connections and two switching positions and can accordingly be embodied on the order of a 2/2-way valve. In the first switching position, shown here, the outlet line 31 is blocked (blocked state). In the other switching position, the outlet line 31 communicates with a return line 33 , which leads to a return 34 , not shown here, which is relatively pressureless and in this sense forms a pressure sink 34 (open state).
- the return or the pressure sink 34 is for instance a reservoir, and in particular a fuel tank.
- the needle body 2 furthermore includes a second control chamber 35 , which is connected via an inlet line 36 to a pressure source 37 .
- This pressure source 37 is for instance a high-pressure fuel line, which serves to supply fuel at high pressure to the injection valve 1 .
- the high-pressure fuel line 37 supplies a plurality of such injection valves 1 simultaneously with fuel on the so-called common rail principle.
- This common high-pressure fuel line 37 is then supplied by a common high-pressure fuel pump, not shown.
- the third control face 38 In the second control chamber 35 , there is a third control face 38 , which is exposed to the pressure prevailing in the second control chamber 35 .
- the third control face 38 is again oriented away from the injection ports 5 , 6 and embodied on the first needle combination 15 .
- the pressure engaging the third control face 38 thus conducts a force, operative in the closing direction 17 , into the first needle combination 15 and hence into the first nozzle needle 7 .
- this first coupling path 39 includes at least one transverse bore 40 , which radially penetrates a cylindrical portion 41 in the first needle combination 15 , in this case the coupling sleeve 14 .
- the positioning of the transverse bore 40 is selected such that it is open toward the second control chamber 35 .
- an annular chamber 42 is formed, which is open toward the first control chamber 28 and into which the transverse bore 40 discharges.
- a communicating connection is created between the control chambers 28 and 35 through the annular chamber 42 and the transverse bore 40 , and this connection also communicates via the inlet line 36 with the high-pressure fuel line 37 , or in other words the pressure source 37 .
- a plurality of such transverse bores 40 may also be provided, which can be expediently distributed over the circumference on the axial portion 41 of the coupling sleeve 14 .
- the first coupling path 39 here thus connects the first control chamber 28 directly to the second control chamber 35 and hence indirectly to the pressure source 37 .
- the first coupling path 39 may be formed by a line which connects the first control chamber 28 directly to the pressure source 37 or directly to the inlet line 36 and thus indirectly to the pressure source 37 . This line could then discharge for instance axially into the first control chamber 28 .
- a second coupling path 43 is provided, which likewise connects the first control chamber 28 directly or indirectly to the pressure source 37 (high-pressure fuel line).
- the second coupling path 43 includes at least one longitudinal groove 44 , which is open toward the first control chamber 28 and which, when the first nozzle needle 7 is closed, protrudes into the second control chamber 35 .
- This longitudinal groove 44 is embodied here in the cylindrical portion 41 of the coupling sleeve 14 .
- the longitudinal groove 44 given a suitably shaped first nozzle needle 7 , could also be embodied directly on the first nozzle needle 7 .
- the longitudinal groove 44 may be embodied not on the first needle combination 15 but rather on the needle body 2 , specifically in a wall 45 radially defining the first control chamber 28 .
- the longitudinal groove 44 would be axially open toward the second control chamber 35 and would be radially open toward the first control chamber 28 .
- the longitudinal groove 44 has an end 46 remote from the first control chamber 28 .
- the needle body 2 also has a wall portion 47 which axially defines the second control chamber 35 . This wall portion 47 and the end 46 of the longitudinal groove 44 form control edges, which cooperate with one another to open and block the second coupling path 43 .
- the second coupling path 43 may for instance also be formed by a line, which is connected directly to the pressure source 37 or directly to the inlet line 36 and hence indirectly to the pressure source 37 .
- This line could then discharge radially into the first control chamber 28 and could be controlled by the outer jacket of the axial portion 41 as a function of the stroke of the first needle combination 15 .
- the first coupling path 39 is disposed or embodied such that is always open, in all the stroke positions of the nozzle needles 7 , 19 .
- the control valve 32 is closed, filling of the first control chamber 28 and thus a pressure buildup in the first control chamber 28 can be assured in any arbitrary relative position of the nozzle needles 7 , 19 to one another and relative to the needle body 2 .
- the first coupling path 39 is expediently more severely throttled than the inlet line 36 , so that via the first coupling path 39 , a pressure drop is made possible.
- the coupling paths 39 and 43 are adapted to one another such that the first coupling path 39 is more severely throttled than the second coupling path 43 .
- the second coupling path 43 is controllable as a function of the stroke of the first nozzle needle 7 .
- An axial spacing between the end 46 of the longitudinal groove 44 and the wall portion 47 defines a prestroke 48 , upon which the second coupling path 43 is switched for the sake of opening and closing.
- the inlet line 36 is expediently disposed such that in all the stroke positions that occur of the nozzle needles 7 , 19 , it is always open and can feed the second control chamber 35 .
- a slaving means 49 is embodied between the first needle combination 15 and the second needle combination 27 .
- This slaving means 49 is designed such that the first needle combination 15 , upon closure, entrains the second needle combination 27 or at least the second nozzle needle 19 in the closing direction 17 .
- the injection ports 5 , 6 are supplied with fuel at high pressure via a fuel supply line 50 .
- this fuel supply line 50 is connected to the pressure source or high-pressure fuel line 37 .
- the fuel supply line 50 discharges into a nozzle chamber 51 , from which an annular chamber 52 leads to the injection ports 5 , 6 .
- the first sealing seat 10 is disposed between the at least one first injection port 5 and the annular chamber 52 , so that the first nozzle needle 7 controls the supply of fuel to the at least one first injection port 5 .
- the second sealing seat 22 is disposed between the at least one second injection port 6 and the annular chamber 52 , so that when the first nozzle needle 7 is open, the second nozzle needle 19 controls the fuel injection through the at least one second injection port 6 .
- the injection nozzle 1 of the invention functions as follows:
- the control valve 32 In the outset position shown in FIG. 1 , the control valve 32 is in the blocking position shown, so that the outlet line 31 is not in communication with the pressure sink 34 . Since the first control chamber 28 moreover communicates, at least via the first coupling path 39 and at short strokes of the first valve combination 15 , indirectly with the pressure source 37 via the second coupling path 43 , the high fuel pressure can build up in the first control chamber 28 . Accordingly, the first control face 29 can introduce a relatively strong closing force into the second needle combination 27 and a resultant force operative in the closing direction 17 is created in the second nozzle needle 19 .
- the second control face 30 introduces a relatively strong closing force into the first needle combination 15 .
- the high fuel pressure also prevails in the second control chamber 35 , so that via the third control face 38 as well, a relatively strong closing force can be introduced into the first needle combination 15 .
- the restoring force of the restoring spring 16 is operative as well. While the pressure forces on the second control face 30 and the third control face 38 and the restoring forces of the restoring spring 16 act in the closing direction 17 , the high fuel pressure at the pressure step 12 of the first nozzle needle 7 generates a force acting in the opening direction 18 .
- a resultant force operative in the closing direction 17 can thus build up in the first nozzle needle 7 as well. Consequently, the first nozzle needle 7 is seated in the first seat 10 , and the second nozzle needle 19 is seated in the second seat 22 .
- the control valve 32 For opening the first nozzle needle 7 , the control valve 32 is adjusted into the open position, and as a result the outlet line 31 is opened and thus communicates with the pressure sink 34 . Accordingly, a pressure drop occurs in the first control chamber 28 . As a result of this pressure drop, a first pressure value can develop in the first control chamber 28 . Since the outlet line 31 has a throttling action, and since via the coupling paths 39 , 43 , replenishing hydraulic fluid permanently flows into the first control chamber 28 when line 31 is open, the first pressure value is indeed less than the high fuel pressure, but is at least greater than the pressure of the pressure sink 34 . At the same time, the pressure also drops in the second control chamber 35 .
- the pressure decrease at the second control face 30 and the third control face 38 leads to reduced closing forces in the first needle combination 15 .
- the involved components of the injection nozzle 1 are adapted to one another in such a way that in the first nozzle needle 7 , a resultant force operative in the opening direction 18 is established and the first nozzle needle 7 lifts from the first seat 10 .
- an injection of fuel occurs through the at least one first injection port 5 .
- the high fuel pressure is essentially applied to the pressure step 24 of the second nozzle needle 19 as well.
- the components of the injection nozzle 1 here are adapted to one another in such a way that in the second needle combination 27 , a resultant force acting in the closing direction 17 continues to result, even though the pressure in the first control chamber 28 has been reduced to the first pressure value, and the pressure step 24 of the second nozzle needle 19 is acted upon by the high fuel pressure.
- the pressure step 24 of the second nozzle needle 19 is made relatively small.
- a restoring spring may also be provided, which is braced on the second needle combination 27 , for instance on the first control face 29 , and introduces a corresponding closing force into the second needle combination 27 . Accordingly, even when the first nozzle needle 7 is opening, the second nozzle needle 19 remains in the second seat 22 .
- the first needle combination 15 executes the predetermined prestroke 48 .
- the control edges, that is the axial end 46 of the longitudinal groove 44 and the wall portion 47 are radially aligned with one another, and as a result the second coupling path 43 is blocked. Because of the blocking or closure of the second coupling path 43 , not as much replenishing hydraulic fluid flows into the first control chamber 28 , so that the pressure there continues to drop, to a second pressure value. In any case, the second pressure value is less than the first pressure value that prevails when the second coupling path 43 is open.
- the second pressure value is also higher than the pressure of the pressure sink 34 .
- the adaptation of the components of the injection nozzle 1 for this state is selected in such a way that the second pressure value at the first control face 29 can now introduce only such slight pressure forces that a resultant force operative in the opening direction 18 is established at the second needle combination 27 , or at the second nozzle needle 19 . Consequently, the second nozzle needle 19 lifts from the second seat 22 . Accordingly, a fuel injection through the at least one second injection port 6 now takes place in addition.
- the first coupling path 39 limits the pressure drop in the first control chamber 28 to the aforementioned second pressure value, so that for the opening stroke of the second nozzle needle 19 or of the second needle combination 27 , only a comparatively low opening speed results.
- a hard impact against a stop face, such as an axial wall 53 of the first control chamber 28 and hence bouncing of the second needle combination 27 can be avoided.
- the second needle combination 27 it is fundamentally possible to design the second needle combination 27 such that it moves in damped fashion against the stop (wall 53 ), which can be achieved for instance by suitable contouring of the first control face 28 .
- the kinematics of the first needle combination 15 change as well.
- the reduced pressure force at the second control face 30 has an effect on the balance of forces at the first needle combination 15 .
- the replenishing medium flowing into the second control chamber 35 via the inlet line 36 can now flow out of the second control chamber 35 only via the first coupling path 39 , so that in the second control chamber 35 , a pressure increase occurs.
- This pressure increase increases the closing force of the third control face 38 , which likewise affects the balance of the forces that engage the first needle combination 15 .
- a damping or braking of the first nozzle needle 7 or the first needle combination 15 can be attained.
- the control valve 32 must be returned to the blocking position shown in good time, before the first nozzle needle 7 reaches the predetermined prestroke 48 .
- the axial length of the prestroke 48 can thus be selected as a function of the opening times for the first nozzle needle 7 .
- the slaving means 49 assures that the first needle combination 15 carries the second needle combination 27 , or at least the second nozzle needle 19 , along with it. As soon as the first nozzle needle 7 arrives in the first seat 10 , the pressure downstream of the first seat 10 drops abruptly, so that then the second needle combination 27 , or the second nozzle needle 19 , moves into the second seat 22 as well.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
An injection nozzle for an internal combustion engine, having a first nozzle needle for controlling the fuel injection through a first injection port, a second nozzle needle for controlling the fuel injection through a second injection port, a first control chamber in which a first control face drive-coupled to the second nozzle needle for introducing closing forces is disposed, and a control line for controlling the pressure in the first control chamber. Especially exact instants of the end of injection can be attained if in the first control chamber, a second control face is disposed that is drive-coupled to the first nozzle needle; a first coupling path connects the first control chamber directly or indirectly to a pressure source; a second coupling path connects the first control chamber directly or indirectly to the pressure source; and the second coupling path is controlled as a function of the stroke of the first nozzle needle such that it is blocked beyond a prestroke of the first nozzle needle.
Description
- 2. Field of the Invention
- The invention relates to an improved fuel injection nozzle for an internal combustion engine.
- 2. Description of the Prior Art
- One injection nozzle known for instance from German Patent Disclosure DE 100 58 153 A1 has a needle body which has at least one first injection port and at least one second injection port and includes both a first nozzle needle and a second nozzle needle. The first nozzle needle is embodied as a hollow needle, and the second nozzle needle is disposed coaxially to and in the first nozzle needle. With the aid of the first nozzle needle, the injection of fuel through the at least one first injection port can be controlled, while the second nozzle needle serves to control the injection of fuel through the at least one second injection port. The needle body includes a first control chamber, in which a first control face is disposed. This first control face is drive-coupled to the second nozzle needle and is oriented such that a pressure prevailing in the first control chamber generates pressure forces at the first control face that introduce closing forces into the second nozzle needle. Communicating with this first control chamber is a control line, with which the pressure in the first control chamber can be controlled.
- In the known injection nozzle, the needle body furthermore includes a pressure chamber to which a fuel supply line is connected. In this pressure chamber, the first nozzle needle has at least one pressure step, which when the pressure chamber is subjected to pressure introduces opening forces into the first nozzle needle. If a low pressure prevails in the fuel supply line, then closing forces, generated by a suitable closing spring, are generated predominantly at the first nozzle needle. For opening the first nozzle needle, a high pressure is generated in the fuel supply line and, in the first nozzle needle by way of its pressure step, this high pressure generates sufficiently high opening forces. The first nozzle needle is thus directly controlled by the pressure applied to its pressure step so that the first nozzle needle is pressure-controlled.
- The second nozzle needle is likewise equipped with a pressure step, but only when the first nozzle needle is opened is it acted upon by the high pressure and is capable of generating forces operative in the opening direction of the second nozzle needle. As long as a suitable high pressure prevails in the first control chamber, the closing forces predominate in the second nozzle needle. If with the first nozzle needle opened, the pressure in the first control chamber is lowered via the control line, then the opening forces predominate at the second nozzle needle. Thus the second nozzle needle is not controlled directly by the pressure applied to its pressure step but rather indirectly via the pressure in the first control chamber. Accordingly, the second nozzle needle in this case is servo-controlled.
- To enable the second nozzle needle to open quickly, the pressure in the first control chamber drops correspondingly fast. As a result, the second nozzle needle is given a relatively high stroke speed. At certain engine operating points, it is necessary for the injection to be terminated again only briefly after the opening of the second nozzle needle. This can result in configurations in which the second nozzle needle closes too early, for instance if because of its high stroke speed it bounces back from a stop that defines the maximum opening stroke of the second nozzle needle. To attain optimal emissions and power values for the engine, however, it must be possible to predetermine the opening and closing instants of the injection nozzle as exactly as possible.
- The injection nozzle of the invention has the advantage over the prior art that upon opening of the second nozzle needle, a lesser stroke speed is established for that nozzle needle, so that no bouncing, or only reduced bouncing, of the second nozzle needle occurs. As a result, the end of injection for the fuel injection through the at least one second injection port, or through all the injection ports, can be predetermined with greater accuracy. This is attained by means of the invention in that the first control chamber is connected for communication to a suitable pressure source directly or indirectly via a first coupling path. As a result, the pressure in the control chamber cannot drop so sharply, since hydraulic fluid, in particular fuel, permanently continues to flow in via the first coupling path. It is also of particular significance in the present invention that now both nozzle needles are servo-controlled. For that purpose, a second control face is provided, which is embodied on the first nozzle needle or is drive-coupled to it and which is disposed in the first control chamber, where it can be acted upon by a pressure acting in the closing direction of the first nozzle needle. The pressure in the first control chamber thus controls both the first nozzle needle and the second nozzle needle. A second coupling path has particular significance here; it likewise connects the first control chamber to the pressure source for communication and is controlled as a function of the stroke of the first nozzle needle. The control of the second coupling path is designed such that beginning at the closing position of the first nozzle needle, the second coupling path is open up to a predetermined prestroke of the first nozzle needle and is blocked beyond a stroke of the first nozzle needle that goes beyond the prestroke. As a result of this design, the first control chamber is supplied with replenishing hydraulic fluid upon the opening of the first nozzle needle, until the prestroke is attained, both through the first coupling path and through the second coupling path. Beyond the prestroke, or in other words when the second coupling path is blocked, the supply of hydraulic fluid to the first control chamber is then effected only via the first coupling path. As a consequence, the pressure in the first control chamber, upon opening of the control line that communicates with the first control chamber, initially drops to a first value and then, when the prestroke is reached, drops to a second value that is less than the first. These pressure values can be designed such that at the first pressure value, only the first nozzle needle opens, while at the second pressure value, the second nozzle needle opens as well. The expense for achieving the servo control of the two nozzle needles is comparatively slight as a result.
- The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments, taken in conjunction with the sole drawing FIGURE which shows a longitudinal section, greatly simplified, through a basic illustration of a preferred exemplary embodiment of the injection nozzle of the invention.
- In
FIG. 1 , an injection nozzle 1 of the invention has aneedle body 2, which protrudes with anozzle tip 3 into acombustion chamber 4 or a mixture-formingchamber 4 of an internal combustion engine, in particular a Diesel engine. In the region of thenozzle tip 3, theneedle body 2 includes at least onefirst injection port 5 and at least onesecond injection port 6. Typically, a plurality offirst injection ports 5 are provided, in particular arranged in a ring. Correspondingly, a plurality ofsecond injection ports 6 may be provided, also expediently arranged in a ring. - In the
needle body 2, afirst nozzle needle 7 is supported with an adjustable stroke. To that end, theneedle body 2 includes afirst needle guide 8, which has a firstguide cross section 9. In the closing position shown here, thefirst nozzle needle 7 is seated in afirst seat 10, which has a firstseat cross section 11. Thefirst nozzle needle 7 is equipped with at least onepressure step 12, which is oriented toward theinjection ports pressure step 12 is embodied by providing that the firstguide cross section 9 is larger than the firstseat cross section 11. - On the side remote from the
first seat 10, thefirst nozzle needle 7 is braced on atransmission body 13, which in this case has a disklike or sleevelike shape. Thetransmission body 13 is in turn braced, on a side remote from thenozzle needle 7, on acoupling sleeve 14. Thefirst nozzle needle 7, thetransmission body 13, and thecoupling sleeve 14 here form afirst needle combination 15, which is supported as a unit, with an adjustable stroke, in theneedle body 2. Since in operation of the injection nozzle 1, solely pressure forces are transmitted among the individual components of thefirst needle combination 15, that is, among thefirst nozzle needle 7, thetransmission body 13, and thecoupling sleeve 14, theindividual components first needle combination 15 can rest quasi-loosely against one another. It is equally possible for theindividual components transmission body 13 and thecoupling sleeve 14, to be combined into a one-piece component. - The
first nozzle needle 7 is assigned a restoringspring 16, by way of which thefirst needle combination 15 is braced on theneedle body 2. The restoringspring 16 may introduce a restoring force, operative in the closing direction represented by anarrow 17, which can be introduced into thefirst nozzle needle 7. The opening direction is correspondingly represented by anarrow 18. The restoringspring 16 is braced here on thetransmission body 13, which thus transmits the restoring force to thefirst nozzle needle 7. - The
first nozzle needle 7 is embodied as a hollow needle and serves in its interior to support asecond nozzle needle 19, which is coaxial with thefirst nozzle needle 7. Accordingly, thefirst nozzle needle 7 includes aneedle guide 20, which has a secondguide cross section 21. Thesecond nozzle needle 19, in the closing direction shown here, is seated in asecond seat 22, which is disposed between the at least onefirst injection port 5 and the at least onesecond injection port 6 and has a secondseat cross section 23. In the preferred embodiment shown here, it may be expedient also to equip thesecond nozzle needle 19 with at least onepressure step 24, which is oriented toward theinjection ports pressure step 24 is embodied by providing that the secondseat cross section 23 is smaller than the secondguide cross section 21. - On a side remote from the
injection ports second nozzle needle 19 is braced on atransmission bolt 25, which in turn is braced on acoupling rod 26. Thesecond nozzle needle 19, thetransmission bolt 25, and thecoupling rod 26 again form a common, adjustable-stroke unit, that is, asecond needle combination 27. If in conventional operation of the injection nozzle 1, solely pressure forces occur inside thesecond needle combination 27, then once again the members of thesecond needle combination 27, that is, thesecond nozzle needle 19, thetransmission bolt 25 and thecoupling rod 26, may rest loosely against one another. Once again, it may be expedient for at least two of thecomponents - The
needle body 2 furthermore includes afirst control chamber 28, in which both afirst control face 29 and asecond control face 30 are disposed. Thefirst control face 29 is a component of thesecond needle combination 27 and is embodied here on thecoupling rod 26. In another embodiment, thefirst control face 29 may also be embodied directly on thesecond nozzle needle 19. Thefirst control face 29 is oriented away from theinjection ports first control face 29 transmits a force acting in the closingdirection 17 on thesecond needle combination 27, which force is thus introduced into thesecond nozzle needle 19. In a distinction from this, thesecond control face 30 is embodied on thefirst needle combination 15 and is likewise oriented away from theinjection ports second control face 30 leads to the introduction of a force effected in the closingdirection 17 into thefirst needle combination 15 and thus into thefirst nozzle needle 7. - The
first control chamber 28 communicates with acontrol line 31, with the aid of which the pressure in thefirst control chamber 28 can be controlled. In the preferred embodiment shown here, thiscontrol line 31 is embodied as an outlet line, and will therefore henceforth be called theoutlet line 31. Theoutlet line 31 here contains acontrol valve 32, which has two connections and two switching positions and can accordingly be embodied on the order of a 2/2-way valve. In the first switching position, shown here, theoutlet line 31 is blocked (blocked state). In the other switching position, theoutlet line 31 communicates with areturn line 33, which leads to areturn 34, not shown here, which is relatively pressureless and in this sense forms a pressure sink 34 (open state). The return or thepressure sink 34 is for instance a reservoir, and in particular a fuel tank. - The
needle body 2 furthermore includes asecond control chamber 35, which is connected via aninlet line 36 to apressure source 37. Thispressure source 37 is for instance a high-pressure fuel line, which serves to supply fuel at high pressure to the injection valve 1. Typically, the high-pressure fuel line 37 supplies a plurality of such injection valves 1 simultaneously with fuel on the so-called common rail principle. This common high-pressure fuel line 37 is then supplied by a common high-pressure fuel pump, not shown. Alternatively, it is equally possible to provide a separate a high-pressure fuel line 37 and/or a separate high-pressure fuel pump for each injection nozzle 1. - In the
second control chamber 35, there is athird control face 38, which is exposed to the pressure prevailing in thesecond control chamber 35. Thethird control face 38 is again oriented away from theinjection ports first needle combination 15. The pressure engaging the third control face 38 thus conducts a force, operative in the closingdirection 17, into thefirst needle combination 15 and hence into thefirst nozzle needle 7. - According to the invention, a
first coupling path 39 is now provided, which directly or indirectly connects thecontrol chamber 28 to the pressure source 37 (high-pressure fuel line). In the special embodiment shown here, thisfirst coupling path 39 includes at least onetransverse bore 40, which radially penetrates acylindrical portion 41 in thefirst needle combination 15, in this case thecoupling sleeve 14. The positioning of thetransverse bore 40 is selected such that it is open toward thesecond control chamber 35. In addition, radially between thefirst needle combination 15 and thesecond needle combination 27, anannular chamber 42 is formed, which is open toward thefirst control chamber 28 and into which the transverse bore 40 discharges. In this way, a communicating connection is created between thecontrol chambers annular chamber 42 and thetransverse bore 40, and this connection also communicates via theinlet line 36 with the high-pressure fuel line 37, or in other words thepressure source 37. It is clear that a plurality of suchtransverse bores 40 may also be provided, which can be expediently distributed over the circumference on theaxial portion 41 of thecoupling sleeve 14. Thefirst coupling path 39 here thus connects thefirst control chamber 28 directly to thesecond control chamber 35 and hence indirectly to thepressure source 37. - Alternatively, the
first coupling path 39 may be formed by a line which connects thefirst control chamber 28 directly to thepressure source 37 or directly to theinlet line 36 and thus indirectly to thepressure source 37. This line could then discharge for instance axially into thefirst control chamber 28. - In addition, a
second coupling path 43 is provided, which likewise connects thefirst control chamber 28 directly or indirectly to the pressure source 37 (high-pressure fuel line). In the preferred embodiment shown here, thesecond coupling path 43 includes at least onelongitudinal groove 44, which is open toward thefirst control chamber 28 and which, when thefirst nozzle needle 7 is closed, protrudes into thesecond control chamber 35. Thislongitudinal groove 44 is embodied here in thecylindrical portion 41 of thecoupling sleeve 14. Thelongitudinal groove 44, given a suitably shapedfirst nozzle needle 7, could also be embodied directly on thefirst nozzle needle 7. Alternatively, it is equally possible for thelongitudinal groove 44 to be embodied not on thefirst needle combination 15 but rather on theneedle body 2, specifically in awall 45 radially defining thefirst control chamber 28. In that case, thelongitudinal groove 44 would be axially open toward thesecond control chamber 35 and would be radially open toward thefirst control chamber 28. Thelongitudinal groove 44 has anend 46 remote from thefirst control chamber 28. Theneedle body 2 also has awall portion 47 which axially defines thesecond control chamber 35. Thiswall portion 47 and theend 46 of thelongitudinal groove 44 form control edges, which cooperate with one another to open and block thesecond coupling path 43. In this way, a control, whose mode of operation will be described in further detail hereinafter, for thesecond coupling path 43 is integrated with the injection nozzle 1. It is clear that preferably a plurality of suchlongitudinal grooves 44 are provided, in particular distributed over the circumference of theaxial portion 41. - Alternatively, the
second coupling path 43 may for instance also be formed by a line, which is connected directly to thepressure source 37 or directly to theinlet line 36 and hence indirectly to thepressure source 37. This line could then discharge radially into thefirst control chamber 28 and could be controlled by the outer jacket of theaxial portion 41 as a function of the stroke of thefirst needle combination 15. - Expediently, the
first coupling path 39 is disposed or embodied such that is always open, in all the stroke positions of the nozzle needles 7, 19. In this way, when thecontrol valve 32 is closed, filling of thefirst control chamber 28 and thus a pressure buildup in thefirst control chamber 28 can be assured in any arbitrary relative position of the nozzle needles 7, 19 to one another and relative to theneedle body 2. - Furthermore, the
first coupling path 39 is expediently more severely throttled than theinlet line 36, so that via thefirst coupling path 39, a pressure drop is made possible. - Expediently, the
coupling paths first coupling path 39 is more severely throttled than thesecond coupling path 43. - The
second coupling path 43 is controllable as a function of the stroke of thefirst nozzle needle 7. An axial spacing between theend 46 of thelongitudinal groove 44 and thewall portion 47 defines aprestroke 48, upon which thesecond coupling path 43 is switched for the sake of opening and closing. - The
inlet line 36 is expediently disposed such that in all the stroke positions that occur of the nozzle needles 7, 19, it is always open and can feed thesecond control chamber 35. - A slaving means 49 is embodied between the
first needle combination 15 and thesecond needle combination 27. This slaving means 49 is designed such that thefirst needle combination 15, upon closure, entrains thesecond needle combination 27 or at least thesecond nozzle needle 19 in the closingdirection 17. - When the nozzle needles 7, 19 are open, the
injection ports fuel supply line 50. To this end, thisfuel supply line 50 is connected to the pressure source or high-pressure fuel line 37. Thefuel supply line 50 discharges into anozzle chamber 51, from which anannular chamber 52 leads to theinjection ports seat 10 is disposed between the at least onefirst injection port 5 and theannular chamber 52, so that thefirst nozzle needle 7 controls the supply of fuel to the at least onefirst injection port 5. The second sealingseat 22 is disposed between the at least onesecond injection port 6 and theannular chamber 52, so that when thefirst nozzle needle 7 is open, thesecond nozzle needle 19 controls the fuel injection through the at least onesecond injection port 6. - The injection nozzle 1 of the invention functions as follows:
- In the outset position shown in
FIG. 1 , thecontrol valve 32 is in the blocking position shown, so that theoutlet line 31 is not in communication with thepressure sink 34. Since thefirst control chamber 28 moreover communicates, at least via thefirst coupling path 39 and at short strokes of thefirst valve combination 15, indirectly with thepressure source 37 via thesecond coupling path 43, the high fuel pressure can build up in thefirst control chamber 28. Accordingly, thefirst control face 29 can introduce a relatively strong closing force into thesecond needle combination 27 and a resultant force operative in the closingdirection 17 is created in thesecond nozzle needle 19. - The
second control face 30 introduces a relatively strong closing force into thefirst needle combination 15. Moreover, the high fuel pressure also prevails in thesecond control chamber 35, so that via the third control face 38 as well, a relatively strong closing force can be introduced into thefirst needle combination 15. The restoring force of the restoringspring 16 is operative as well. While the pressure forces on thesecond control face 30 and thethird control face 38 and the restoring forces of the restoringspring 16 act in the closingdirection 17, the high fuel pressure at thepressure step 12 of thefirst nozzle needle 7 generates a force acting in theopening direction 18. - Overall, a resultant force operative in the closing
direction 17 can thus build up in thefirst nozzle needle 7 as well. Consequently, thefirst nozzle needle 7 is seated in thefirst seat 10, and thesecond nozzle needle 19 is seated in thesecond seat 22. - For opening the
first nozzle needle 7, thecontrol valve 32 is adjusted into the open position, and as a result theoutlet line 31 is opened and thus communicates with thepressure sink 34. Accordingly, a pressure drop occurs in thefirst control chamber 28. As a result of this pressure drop, a first pressure value can develop in thefirst control chamber 28. Since theoutlet line 31 has a throttling action, and since via thecoupling paths first control chamber 28 whenline 31 is open, the first pressure value is indeed less than the high fuel pressure, but is at least greater than the pressure of thepressure sink 34. At the same time, the pressure also drops in thesecond control chamber 35. The pressure decrease at thesecond control face 30 and the third control face 38 leads to reduced closing forces in thefirst needle combination 15. The involved components of the injection nozzle 1 are adapted to one another in such a way that in thefirst nozzle needle 7, a resultant force operative in theopening direction 18 is established and thefirst nozzle needle 7 lifts from thefirst seat 10. - As a consequence, an injection of fuel occurs through the at least one
first injection port 5. - As soon as the
first nozzle needle 7 lifts from thefirst seat 10, the high fuel pressure is essentially applied to thepressure step 24 of thesecond nozzle needle 19 as well. The components of the injection nozzle 1 here are adapted to one another in such a way that in thesecond needle combination 27, a resultant force acting in the closingdirection 17 continues to result, even though the pressure in thefirst control chamber 28 has been reduced to the first pressure value, and thepressure step 24 of thesecond nozzle needle 19 is acted upon by the high fuel pressure. For instance, for this purpose, thepressure step 24 of thesecond nozzle needle 19 is made relatively small. A restoring spring, not shown here, may also be provided, which is braced on thesecond needle combination 27, for instance on thefirst control face 29, and introduces a corresponding closing force into thesecond needle combination 27. Accordingly, even when thefirst nozzle needle 7 is opening, thesecond nozzle needle 19 remains in thesecond seat 22. - If the
control valve 32 is open long enough, then beginning at the outset position, in which thefirst nozzle needle 7 is seated in thefirst seat 10, thefirst needle combination 15 executes thepredetermined prestroke 48. As soon as thisprestroke 48 has been executed, the control edges, that is theaxial end 46 of thelongitudinal groove 44 and thewall portion 47 are radially aligned with one another, and as a result thesecond coupling path 43 is blocked. Because of the blocking or closure of thesecond coupling path 43, not as much replenishing hydraulic fluid flows into thefirst control chamber 28, so that the pressure there continues to drop, to a second pressure value. In any case, the second pressure value is less than the first pressure value that prevails when thesecond coupling path 43 is open. Since as before, thefirst coupling path 39 allows a replenishing flow of hydraulic fluid into thefirst control chamber 28, the second pressure value is also higher than the pressure of thepressure sink 34. The adaptation of the components of the injection nozzle 1 for this state is selected in such a way that the second pressure value at thefirst control face 29 can now introduce only such slight pressure forces that a resultant force operative in theopening direction 18 is established at thesecond needle combination 27, or at thesecond nozzle needle 19. Consequently, thesecond nozzle needle 19 lifts from thesecond seat 22. Accordingly, a fuel injection through the at least onesecond injection port 6 now takes place in addition. - It is notable here that the
first coupling path 39 limits the pressure drop in thefirst control chamber 28 to the aforementioned second pressure value, so that for the opening stroke of thesecond nozzle needle 19 or of thesecond needle combination 27, only a comparatively low opening speed results. In particular, a hard impact against a stop face, such as anaxial wall 53 of thefirst control chamber 28, and hence bouncing of thesecond needle combination 27 can be avoided. - Furthermore, it is fundamentally possible to design the
second needle combination 27 such that it moves in damped fashion against the stop (wall 53), which can be achieved for instance by suitable contouring of thefirst control face 28. - As soon as the
first nozzle needle 7 has exceeded theprestroke 48, the kinematics of thefirst needle combination 15 change as well. For one thing, the reduced pressure force at thesecond control face 30 has an effect on the balance of forces at thefirst needle combination 15. As a result of the blockedsecond coupling path 43, the replenishing medium flowing into thesecond control chamber 35 via theinlet line 36 can now flow out of thesecond control chamber 35 only via thefirst coupling path 39, so that in thesecond control chamber 35, a pressure increase occurs. This pressure increase increases the closing force of thethird control face 38, which likewise affects the balance of the forces that engage thefirst needle combination 15. Depending on the design, a damping or braking of thefirst nozzle needle 7 or thefirst needle combination 15 can be attained. - If only an injection through the at least one
first injection port 5 is wanted, then thecontrol valve 32 must be returned to the blocking position shown in good time, before thefirst nozzle needle 7 reaches thepredetermined prestroke 48. The axial length of theprestroke 48 can thus be selected as a function of the opening times for thefirst nozzle needle 7. - To close the nozzle needles 7 and 19, the
control valve 32 is shifted to the closing position shown. The result is a sharp pressure increase in both thefirst control chamber 28 and thesecond control chamber 35, with the consequence that the balance of forces at thefirst needle combination 15 is reversed again, resulting in a force in the closingdirection 17 that drives thefirst needle combination 15 ahead in the closingdirection 17. Since with thesecond nozzle needle 19 open, the high fuel pressure engages the second seat cross section in theopening direction 18 as well, it can happen that the balance of forces at thesecond needle combination 27, despite the high pressure at thefirst control face 29, does not produce closing force, or only a relatively slight resultant closing force. In this case, the slaving means 49 assures that thefirst needle combination 15 carries thesecond needle combination 27, or at least thesecond nozzle needle 19, along with it. As soon as thefirst nozzle needle 7 arrives in thefirst seat 10, the pressure downstream of thefirst seat 10 drops abruptly, so that then thesecond needle combination 27, or thesecond nozzle needle 19, moves into thesecond seat 22 as well. - The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
Claims (20)
1. An injection nozzle for an internal combustion engine, comprising
a needle body (2), having at least one first injection port (5) and at least one second injection port (6),
a first nozzle needle (7), embodied as a hollow needle, with which the injection of fuel through the at least one first injection port (5) can be controlled,
a second nozzle needle (19), disposed coaxially to the first nozzle needle (7), with which the injection of fuel to the at least one second injection port (6) can be controlled,
a first control chamber (28), in which a first control face (29) embodied at or drive-coupled with the second nozzle needle (19) is disposed for initiating closing forces into the second nozzle needle (19),
a control line (31), which communicates with the first control chamber (28) and with which the pressure in the first control chamber (28) can be controlled,
a second control face (30) in the first control chamber (28), the second control face (30), being embodied at or drive-coupled with the first nozzle needle (7) for initiating closing forces into the first nozzle needle (7);
first coupling path (39) connecting the first control chamber (28) directly or indirectly for communication with a pressure source (37); and
a second coupling path (43), connecting the first control chamber (28) for communication with the pressure source (37);
the second coupling path (43) being controlled as a function of the stroke of the first nozzle needle (7), in such a way that the second coupling path (43), beginning at the closing position of the first nozzle needle (7), is open up to a predetermined prestroke (48), and is blocked beyond a stroke extending beyond the prestroke (48).
2. The injection nozzle in accordance with claim 1 , further comprising
a second control chamber (35), in which a third control face (38), embodied at or drive-coupled with the first nozzle needle (7), is disposed for initiating closing forces into the first nozzle needle (7); and
an inlet line (36) connecting the second control chamber (35) to the pressure source (37);
the second coupling path (43) connecting the first control chamber (28) for communication with the second control chamber (35), so that the first control chamber (28) communicates with the pressure source (37) through the second control chamber (35).
3. The injection nozzle in accordance with claim 2 , wherein the second coupling path (43) has at least one longitudinal groove (44), which is open toward the first control chamber (28) and is embodied in a cylindrical portion (41) of the first nozzle needle (7) or in a coupling sleeve (14) drive-coupled to the first nozzle needle (7), and which when the first nozzle needle (7) is closed protrudes into the second control chamber (35); and wherein an end (46), remote from the first control chamber (28), of the longitudinal groove (44) and a wall portion (47), axially defined by the second control chamber (35), cooperate as control edges for opening and blocking the second coupling path (43).
4. The injection nozzle in accordance with claim 1 , wherein the first coupling path (39) is throttled more severely than the second coupling path (43).
5. The injection nozzle in accordance with claim 2 , wherein the first coupling path (39) is throttled more severely than the second coupling path (43).
6. The injection nozzle in accordance with claim 3 , wherein the first coupling path (39) is throttled more severely than the second coupling path (43).
7. The injection nozzle in accordance with claim 1 , wherein the first coupling path (39) is throttled more severely than the inlet line (36).
8. The injection nozzle in accordance with claim 3 , wherein the first coupling path (39) is throttled more severely than the inlet line (36).
9. The injection nozzle in accordance with claim 1 , wherein the control line comprises an outlet line (31) connecting the first control chamber (28) to a pressure sink (34); and
means switching the connection can be switched at least between an open state and a blocked state.
10. The injection nozzle in accordance with claim 3 , wherein the control line comprises an outlet line (31) connecting the first control chamber (28) to a pressure sink (34); and
means switching the connection can be switched at least between an open state and a blocked state.
11. The injection nozzle in accordance with claim 4 , wherein the control line comprises an outlet line (31) connecting the first control chamber (28) to a pressure sink (34); and
means switching the connection can be switched at least between an open state and a blocked state.
12. The injection nozzle in accordance with claim 7 , wherein the control line comprises an outlet line (31) connecting the first control chamber (28) to a pressure sink (34); and
means switching the connection can be switched at least between an open state and a blocked state.
13. The injection nozzle in accordance with claim 1 , wherein the outlet line (31), the inlet line (36), the coupling paths (39, 43), the nozzle needles (7, 19), and the control faces (29, 30, 38) are designed such that in the open state of the outlet line (31), a pressure is established in the first control chamber (28) that, when the second coupling path (43) is open, is so great that a resultant force, engaging the second nozzle needle (19), acts in the closing direction (17) of the second nozzle needle (19), and when the second coupling path (43) is blocked is so great that the resultant force engaging the second nozzle needle (19) acts in the opening direction (18) of the second nozzle needle (19).
14. The injection nozzle in accordance with claim 9 , wherein the outlet line (31), the inlet line (36), the coupling paths (39, 43), the nozzle needles (7, 19), and the control faces (29, 30, 38) are designed such that in the open state of the outlet line (31), a pressure is established in the first control chamber (28) that, when the second coupling path (43) is open, is so great that a resultant force, engaging the second nozzle needle (19), acts in the closing direction (17) of the second nozzle needle (19), and when the second coupling path (43) is blocked is so great that the resultant force engaging the second nozzle needle (19) acts in the opening direction (18) of the second nozzle needle (19).
15. The injection nozzle in accordance with claim 1 , wherein the first coupling path (39) connects the first control chamber (28) for communication with the second control chamber (35), so that the first control chamber (28) communicates with the pressure source (37) through the second control chamber (35).
16. The injection nozzle in accordance with claim 4 , wherein the first coupling path (39) connects the first control chamber (28) for communication with the second control chamber (35), so that the first control chamber (28) communicates with the pressure source (37) through the second control chamber (35).
17. The injection nozzle in accordance with claim 12 , wherein the first coupling path (39) connects the first control chamber (28) for communication with the second control chamber (35), so that the first control chamber (28) communicates with the pressure source (37) through the second control chamber (35).
18. The injection nozzle in accordance with claim 1 , further comprising to at least one transverse bore (40), which radially penetrates a cylindrical portion (41) in the first nozzle needle (7) or in a coupling sleeve (14) drive-coupled to the first nozzle needle (7) defining at least a portion of the first coupling path (43), and an annular chamber (42) disposed radially between the second nozzle needle (19), or a coupling rod (26) drive-coupled to the second nozzle needle (19), and the first nozzle needle (7), or a coupling sleeve (14) drive-coupled to the first nozzle needle (7), the annular chamber (42) being open toward the first control chamber (28) and communicating with the second control chamber (35) via the at least one transverse bore (40).
19. The injection nozzle in accordance with claim 1 , wherein the first coupling path (39) is disposed such that it is open in all the stroke positions of the nozzle needles (7, 19).
20. The injection nozzle in accordance with claim 1 , wherein the inlet line (36) is disposed such that it is open in all the stroke positions of the nozzle needles (7, 19).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE10343998.6 | 2003-09-23 | ||
DE10343998A DE10343998A1 (en) | 2003-09-23 | 2003-09-23 | injection |
Publications (1)
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US20050089426A1 true US20050089426A1 (en) | 2005-04-28 |
Family
ID=34177903
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US10/945,990 Abandoned US20050089426A1 (en) | 2003-09-23 | 2004-09-22 | Injection nozzle |
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US (1) | US20050089426A1 (en) |
EP (1) | EP1519032A1 (en) |
DE (1) | DE10343998A1 (en) |
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WO2009031713A1 (en) * | 2007-09-07 | 2009-03-12 | Toyota Jidosha Kabushiki Kaisha | Fuel injection control device for internal combustion engine |
US10415522B2 (en) * | 2015-11-23 | 2019-09-17 | Robert Bosch Gmbh | Fuel injector |
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Publication number | Priority date | Publication date | Assignee | Title |
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JP4710892B2 (en) | 2007-09-20 | 2011-06-29 | トヨタ自動車株式会社 | Fuel injection control device for internal combustion engine |
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DE4123721C1 (en) * | 1991-07-17 | 1992-06-17 | Steyr-Daimler-Puch Ag, Wien, At | Fuel injection system with pump and nozzle units - has laterally coupled pump duct to chamber in piston bush |
DE10205970A1 (en) * | 2002-02-14 | 2003-09-04 | Bosch Gmbh Robert | Fuel injection valve for internal combustion engines |
DE10246974A1 (en) * | 2002-10-09 | 2004-04-22 | Robert Bosch Gmbh | Fuel injector nozzle for use in internal combustion engine has needle and sleeve separately cutting off fuel flow to inner and outer nozzle bores |
-
2003
- 2003-09-23 DE DE10343998A patent/DE10343998A1/en not_active Withdrawn
-
2004
- 2004-07-30 EP EP04018073A patent/EP1519032A1/en not_active Withdrawn
- 2004-09-22 US US10/945,990 patent/US20050089426A1/en not_active Abandoned
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4687136A (en) * | 1985-02-15 | 1987-08-18 | Kawasaki Jukogyo Kabushiki Kaisha | Gas injection valve for gas engine |
US6220528B1 (en) * | 1998-06-24 | 2001-04-24 | Lucas Industries | Fuel injector including an outer valve needle, and inner valve needle slidable within a bore formed in the outer valve needle |
US6260775B1 (en) * | 1998-06-24 | 2001-07-17 | Lucas Industries | Fuel injector including outer valve needle and inner valve needle slidable within a passage provided in the outer valve needle |
US6338445B1 (en) * | 1999-10-06 | 2002-01-15 | Delphi Technologies, Inc. | Fuel injector |
US6637675B2 (en) * | 2001-07-13 | 2003-10-28 | Cummins Inc. | Rate shaping fuel injector with limited throttling |
US6557776B2 (en) * | 2001-07-19 | 2003-05-06 | Cummins Inc. | Fuel injector with injection rate control |
US6811105B2 (en) * | 2001-11-16 | 2004-11-02 | Denso Corporation | Fuel injection nozzle |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009031713A1 (en) * | 2007-09-07 | 2009-03-12 | Toyota Jidosha Kabushiki Kaisha | Fuel injection control device for internal combustion engine |
JP2009062920A (en) * | 2007-09-07 | 2009-03-26 | Toyota Motor Corp | Fuel injection control device for internal combustion engine |
US20100170475A1 (en) * | 2007-09-07 | 2010-07-08 | Fumihiro Okumura | Fuel injection control device for internal combustion engine |
US8347851B2 (en) | 2007-09-07 | 2013-01-08 | Toyota Jidosha Kabushiki Kaisha | Fuel injection control device for internal combustion engine |
US10415522B2 (en) * | 2015-11-23 | 2019-09-17 | Robert Bosch Gmbh | Fuel injector |
Also Published As
Publication number | Publication date |
---|---|
DE10343998A1 (en) | 2005-04-14 |
EP1519032A1 (en) | 2005-03-30 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ROBERT BOSCH GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KURZ, MICHAEL;BOLTZ, JOACHIM;REEL/FRAME:015549/0878;SIGNING DATES FROM 20040909 TO 20040929 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |