Classifications

• • 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
• • 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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
• • 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
• • 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
  • F02M2200/31—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements
• • 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
  • F02M2200/31—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements
  • F02M2200/315—Fuel-injection apparatus having hydraulic pressure fluctuations damping elements for damping fuel pressure fluctuations
• • 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
  • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
  • F02M2547/003—Valve inserts containing control chamber and valve piston
• • 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
  • F02M63/0012—Valves
  • F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
  • F02M63/0078—Valve member details, e.g. special shape, hollow or fuel passages in the valve member
  • F02M63/008—Hollow valve members, e.g. members internally guided

Definitions

• the invention relates to a fuel injector, in particular a common rail injector, for injecting fuel into a combustion chamber of an internal combustion engine according to the preamble of claim 1.
• the invention has for its object to propose a designed for highest injection pressures fuel injector. Preferably, this should be produced with conventional materials such as C45 steel.
• injector bodies of fuel injectors designed for well over 2000 bar to be designed with conventional materials such as C45 steel, in particular if the fuel pressure in the annular space does not exceed about 1800 bar , If the pressure in the high-pressure chamber of the fuel injector is, for example, at most 2000 bar, it is generally sufficient if the pressure difference between the annular space and the high-pressure space is approximately 200 bar.
• the pressure in the annular space during operation of the fuel injector is at least half as high as the pressure in the pressure chamber so as not to burden the separation between the annulus and the high-pressure chamber overly.
• the fuel flowing in from the fuel supply connection from an external high-pressure fuel accumulator (rail) is conducted directly into the high-pressure space.
• a channel passing through the annular space in the radial direction is preferably provided, which is formed, for example, by the injector component which radially bounds the annular space.
• the fuel injector is preferably a so-called low-leakage injector, preferably without a permanent, low-pressure stage which produces a hydraulic closing force acting on the one-part or multi-part injection valve element.
• Such fuel injectors are preferably equipped with a long injection valve element whose axial extent preferably corresponds to at least 50%, preferably at least 60% or 70%, of the axial extent of the entire fuel injector.
• the high-pressure space in which the injection valve element is accommodated extends in the axial direction as far as a nozzle hole arrangement, wherein the high-pressure space can be subdivided as required into two axially adjacent space sections, between which a closing throttle is arranged is to lower the fuel pressure in the region of an injection valve element tip slightly, for example by 100 to 200 bar, thereby to produce a hydraulic closing force component.
• the high-pressure chamber extends in the axial direction into a nozzle body which is axially adjacent to the injector body, in which case an embodiment can also be realized in which the pressure-reduced annular space formed between the injector body and the high-pressure chamber extends in the axial direction as far as into the nozzle body.
• a series-connected throttle combination which consists of at least one annular space inlet throttle and at least one annular space drain throttle, flowing over the annular space inlet throttle under high pressure, in particular at least approximately under rail pressure, standing fuel in the annulus can.
• Fuel can in turn flow out of the annular space in the direction of the low-pressure region of the fuel injector via the annular space drain throttle, wherein the flow cross-sections of the at least one annular space inlet throttle and the at least one annular space drain throttle are dimensioned such that the desired pressure difference between annular space and high-pressure space adjusts.
• This pressure reduction mechanism is comparable to known Steuerraumdruckab- reduction, as is known from servo-controlled fuel injectors.
• the essential difference is that the annular space pressure in comparison to the control chamber pressure has no influence on the injection behavior of the fuel injector, so that a lower accuracy requirement can be made in the production of the at least one annular space inlet throttle and the at least one annulus flow restrictor.
• the at least one annular space inlet throttle and / or the at least one annular space outlet throttle are structurally realized via a guide and / or a leak gap, as a result of which additional working steps for producing throttle bores can be saved.
• the at least one annulus drain can also be replaced or formed by a pressure relief valve to be explained later.
• an embodiment of the fuel injector is not lowered in the pressure in the annulus during the entire operating time against the pressure in the high pressure chamber, but only at times when the pressure in the high pressure chamber exceeds a critical limit. This is usually only the case when the internal combustion engine is operated under full load.
• an embodiment is preferred in which the pressure in the annular space is reduced or reduced in comparison with the pressure in the high-pressure space only when a minimum pressure, in particular of approximately 1800 bar, is exceeded.
• At least one pressure relief valve is provided in the fuel flow direction between the annulus and the low pressure region of the fuel injector, which is preferably designed as a check valve.
• the overpressure valve is designed in such a way that it acts as an annular space outlet throttle in the open state, so that the desired annular space pressure is set in a defined manner. Due to the only temporary opening of the pressure relief valve, the parasitic drainage quantity can be reduced to an absolute minimum.
• the overpressure valve comprises at least one spring which has an adjustable valve element spring-force-loaded. beat.
• the spring is particularly preferably a leaf spring and / or the valve element is a valve ball, in particular designed as a steel ball.
• Structurally elegant is an embodiment in which the valve element is pressed by the spring onto a valve seat which is formed on an injector component axially delimiting the low-pressure region.
• the leaf spring can be clamped axially between a valve clamping screw for securing the injector component in the injector body and the injector component.
• the adjustable valve element of the pressure relief valve is formed by the low pressure region axially limiting injector component, said injector component is in this case by means of a spring, for example an expansion sleeve or a disc spring, against the injector body spring-loaded.
• a spring for example an expansion sleeve or a disc spring
• the fuel from the annulus with open pressure relief valve flows through an annular leakage gap in the low pressure region of the fuel injector, wherein the leakage gap, preferably axially, is formed between the Injektorbauteil and the injector, wherein to ensure sufficient tightness of the closed overpressure valve on the injector body and / or on the injector component, preferably at least one biting edge is formed.
• the spring of the pressure relief valve is arranged such that the bias of the spring and thus the maximum pressure of the annular space is adjustable by means of a valve clamping screw, the valve clamping screw preferably an axial securing for the low pressure region of the Fuel injector in the axial direction limiting injector component.
• FIG. 1 shows a first embodiment of a fuel injector with an annular space formed between a high-pressure chamber and an injector body in which the fuel pressure during operation of the fuel injector relative to the fuel pressure in
• Fig. 2 an alternative, second embodiment of a fuel Inj ector arranged between the annulus and low pressure region of the fuel injector designed as a check valve overpressure valve, which has the task to reduce the fuel pressure in the annulus only when a minimum pressure is exceeded and
• FIG. 3 shows a further alternative, third exemplary embodiment of a fuel injector, in which the valve element of the pressure relief valve is formed by an injector component delimiting a control chamber.
• FIG. 1 shows a fuel injector 1 designed as a common-rail injector for injecting fuel into a combustion chamber, not shown, of an internal combustion engine of a motor vehicle.
• a high pressure pump 2 delivers fuel from a reservoir 3 into a high-pressure fuel accumulator 4 (rail).
• this fuel especially diesel or gasoline, under high pressure, of about 2500 bar in this embodiment, stored.
• the fuel injector 1 is connected, among other injectors, not shown, via a supply line 5.
• This supply line 5 leads to a fuel supply connection 6 of the fuel Inj ector 1, which leads via a supply channel 7 to a central, serving as a minirail high pressure chamber 8.
• this high-pressure chamber 8 there is essentially rail pressure of about 2500 bar.
• a fuel return port 10 is provided, to which a return line 11 is connected.
• a control quantity to be explained later and a leakage quantity of fuel can be discharged from a low-pressure region 12 of the fuel injector 1 to the reservoir 3, which is also at low pressure of approximately 1 to 10 bar.
• an injection valve element 13 which is integral in the embodiment shown is one recorded axially adjustable.
• the injection valve element 13 is designed in several parts and consists for example of an upper control rod and a lower nozzle needle.
• the injection valve element 13 is guided longitudinally displaceable in a guide bore 14 of a lower nozzle body 15 in the drawing plane.
• axial channels 16 are realized on the outer circumference of the injection valve element 13 in the region of its lower guide as polished sections, via which the fuel can flow in the axial direction down to a nozzle hole arrangement 17 when the injection valve element 13 is open.
• the nozzle body 15 is clamped by means of a union nut 18 with an injector body 19.
• the injector body 19 forms the largest housing part of a housing 20.
• the injection valve element 13 has at its tip 21 a closing surface 22 with which the injection valve element 13 can be brought into tight contact with an injection valve element seat 23 formed inside the nozzle body 15.
• an injection valve element seat 23 formed inside the nozzle body 15.
• the injection valve element 13 abuts against its injection valve element seat 23, ie is in a closed position, the fuel outlet from the nozzle hole arrangement 17 is blocked. If, on the other hand, it is lifted off its injection valve element seat 23, fuel can flow from the high-pressure chamber 8 in the axial direction via the axial channels 16 into a lower nozzle space 24 designed as an annular space and from there past the injection valve element seat 23 to the nozzle hole arrangement 17 and there substantially under high pressure (FIG. Rail pressure) standing in the combustion chamber (not shown) to be injected.
• FOG. Rail pressure high pressure standing in the combustion chamber
• a control chamber 28 is limited, which is supplied via an introduced into the injection valve element 13 inlet throttle 29 with fuel from the high-pressure chamber 8.
• the control chamber 28 is connected via a axially extending in the injector component 27 drain passage 30 with outlet throttle 31 with a valve chamber 32 of a control valve 33 (servo-valve).
• the valve chamber 32 is bounded radially on the outside by a sleeve-shaped control valve element 34.
• the sleeve-shaped control valve element 34 is substantially pressure-balanced in its closed position in the axial direction.
• valve chamber 32 is bounded in the axial direction upward by a pressure pin 35, which is supported axially on Injektorde- disgust 9 and is formed as a component separate from the injector component 27.
• a co-operating with the sleeve-shaped control valve element 34 control valve seat 36 (here flat seat) is formed on the injector component 27.
• the sleeve-shaped control valve element 34 is integrally formed with an anchor plate 37 which cooperates with an electromagnetic actuator 38. If this is energized, lifts the control valve member 34 in the axial direction of its control valve seat 36 so that fuel from the valve chamber 32 and subsequently from the control chamber 28 in the low pressure region 12 and from there via the fuel return port 10 and the return line 11 to the reservoir 3 can flow out.
• the flow cross-sections of the inlet throttle 29, which may alternatively be embodied, for example, in the injector component 27, and the outlet throttle 31 are matched to one another such that when the control valve 33 is open, a net outflow of fuel from the control chamber 28 results. with the result that the fuel pressure in the control chamber 33 drops rapidly and thus a hydraulic opening force acts on the injection valve element 13, which lifts in sequence from its injection valve element seat 23 and the nozzle hole assembly 17 for injecting fuel into the combustion chamber releases.
• the energization of the electromagnetic actuator 38 is interrupted. With a one end on a shoulder of the pressure pin 35 and the other end on an upper end face of the armature plate 37 supporting the control closing spring 39, the sleeve-shaped control valve member 34 is moved back to its control valve seat 36.
• the fuel flowing in through the inlet throttle 29 causes an increase in pressure in the control chamber 28, with the result that the injection valve element 13 is moved back onto the injection valve element seat 23 assisted by a closing spring 40.
• the closing spring 40 is arranged in the high-pressure space 8 projecting into the nozzle body 15 and is supported at one end on a lower end face of the injector component 27 and at the other end against a circumferential collar 41 of the injection valve element 13.
• the axial channels 16 may be formed as throttle channels, thus reducing the pressure in the nozzle chamber 24 in comparison to the high pressure chamber 8 something.
• the pressure is advantageously reduced by only about 100 to 200 bar, so that the nozzle chamber 24 and the high-pressure chamber 8 can be regarded as a common space.
• the fuel injector 1 shown in FIG. 1 provides an annular space 42 extending radially in between the high-pressure chamber 8 and the injector body 19 is located.
• the annular space 42 extends in the axial direction over the largest part of the axial extent of the injector body 19 and, if necessary, can also project axially into the nozzle body 15.
• the annular space 42 is bounded radially inwards with respect to the high-pressure space 8 by a tubular portion 43 of the injector component 27.
• a stepped bore 44 is introduced for this purpose, which delimits the control chamber 28 in its upper end in the drawing plane.
• the pressure in the annular space 42 is permanently lower than in the high pressure chamber 8. Die Flow cross sections of the chokes to be explained below are adjusted so that the pressure in the annular space 42 does not exceed 1800 bar. As a result, the pressure load of the injector body 19, at least in druckkriti- see areas reduced over most of its axial extent.
• the supply channel 7 is formed in sections as a bore in a sleeve-shaped connection part 60 screwed to the injector body 19, wherein the supply channel 7 continues in the radial direction into the high-pressure space 8, and thereby the annular space 42 in FIG Passed through radial direction and sealed against this.
• the injector component 22 is provided with a positive diameter jump 45 (circumferential collar) in the region of the supply channel 7, into which recesses 46 running at a distance from the supply channel 7 are introduced, via which the fuel flows from a lower section of the annular space 42 into an upper one Section of the annular space 42 can flow unhindered and preferably unthrottled.
• the injector component 27 shown in FIG. 1 does not necessarily have to be made in one piece.
• the annular space 42 is bounded by the plate section 47 of the injector component 27, which, as mentioned above, can also be embodied as a separate component. This is pressed by a valve clamping screw 48 against an annular shoulder 49 of the injector body 19.
• a sealing element 50 In the axial direction down the annular space 42 is bounded by a sealing element 50, which is located radially between the lower region of the tubular section 43 of the injector component 27 and the injector body 19.
• 2500 bar of fuel can flow in the radial direction via an annular space inlet throttle 51 into the annular space 42. From there, fuel flows through an annular component outlet throttle 52 provided in the injector component 27 into the low-pressure region 12 of the fuel injector 1.
• the flow cross-sections of the annular space inlet throttle 51 and the annular space outlet throttle 52 are matched to one another such that the pressure in the annular space 42, as explained above, does not exceed a maximum pressure of 1800 bar, whereby the pressure load of the injector body 19 is significantly reduced.
• the annular space inlet throttle 51 and the annular space outlet throttle 52 are designed as throttle bores, whereby alternative production possibilities can also be realized.
• the annular space inlet throttle 51 and the annular space drain throttle 52 can be made very small, whereby the necessary for the pressure reduction parasitic flow rate is low.
• the pressure in the annular space 42 does not react to highly dynamic pressure changes in the high-pressure space 8 serving as a minirail, but only to function-related rail pressure changes.
• FIGS. 2 and 3 further alternative embodiments of a fuel injector 1 are explained with reference to FIGS. 2 and 3.
• the structure of these embodiments substantially corresponds to that shown in Fig. 1 and before described embodiment.
• FIG. 1 With regard to common features, reference is made to FIG. 1 and the preceding description of the figures.
• the pressure in the annular space 42 is not permanently reduced in the embodiment of FIG. 2 compared to the high-pressure chamber 8. This is due to the fact that the fuel from the annular space 42 can only temporarily flow into the low-pressure region 12 of the fuel Inj ector 1.
• the flow from the high-pressure chamber 8 into the annular space 42 also takes place in the exemplary embodiment shown in FIG. 2 via an annular space inlet throttle 51 designed as a throttle bore.
• the annular space drain throttle 52 is formed by a pressure relief valve 53 designed as a check valve in the embodiment according to FIG is designed that this opens only in the direction of low pressure area 12 when a minimum pressure in the annular space 42 is exceeded.
• the overpressure valve 53 comprises a valve element 54 formed as a steel ball, which is acted upon by a spring 55 designed as a flat spring in the direction of a valve seat 56 formed on the injector component 27, more precisely on the plate section 47.
• a spring 55 designed as a flat spring in the direction of a valve seat 56 formed on the injector component 27, more precisely on the plate section 47.
• the underside of the valve element 54 via a channel 57 in the injector 27 is permanently in communication with the annulus volume of the annular space 42.
• the pressure relief valve 53 is dimensioned so that the throttling action of the pressure relief valve 53 has the desired level of pressure reduction in the annular space 42 result.
• the spring 55 designed as a flat spring is clamped axially between the valve clamping screw 48 and the upper side of the plate section 47 of the injector component 27 in the plane of the drawing.
• the exemplary embodiment of a fuel injector 1 shown in FIG. 3 functions on the same principle as the exemplary embodiment shown in FIG. 2 and described above.
• the annular space inlet throttle 51 is not designed as a throttle bore but as a leakage gap between a circumferential collar 58 of the tubular section 43 of the injector component 27 and the injector body 19.
• a further annular space inlet throttle 51 is provided between the upper positive diameter jump 45 (circumferential collar) and the injector body 19.
• annular space drain throttle 52 no throttle channel is provided as annular space drain throttle 52.
• This is formed by the pressure relief valve 53, via which the annular space 42 is connected to the low-pressure region 12 of the fuel Inj ector 1.
• the valve element 54 is formed by the plate portion 47 of the Injektorbauteils 27. This is in the closed state of the pressure relief valve 53 on the annular shoulder 49 of the injector body 9 on.
• the overpressure valve 53 is open, the plate section 47 is adjusted in the axial direction upward, so that an annular gap is formed axially between the plate section 47 and a biting edge 59 of the injector body 19, with the flow cross-section of the annular gap being adjusted so that the desired throttling is achieved ,
• the plate section 47 only lifts off from its valve seat 56 formed by the biting edge 59 on the injector body 19 when the pressure force acting on it exceeds the spring force of a spring 55 designed as a plate spring, which is supported in the axial direction upward on the valve clamping screw 48.
• the spring 55 tends to press the plate portion 47 axially downwardly against the annular shoulder 49 of the injector body 19.

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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)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40887985

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (5)

Citations (5)

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• 2008
  • 2008-06-19 DE DE102008002527A patent/DE102008002527A1/de not_active Withdrawn
• 2009
  • 2009-04-22 WO PCT/EP2009/054814 patent/WO2009153087A1/de active Application Filing
  • 2009-04-22 EP EP09765667.2A patent/EP2294309B1/de not_active Not-in-force
  • 2009-04-22 CN CN200980123041.7A patent/CN102066741B/zh not_active Expired - Fee Related
  • 2009-04-22 BR BRPI0914857-4A patent/BRPI0914857A2/pt not_active Application Discontinuation
  • 2009-04-22 RU RU2011101635/06A patent/RU2541484C2/ru not_active IP Right Cessation

Patent Citations (5)

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