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
  • 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
  • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
  • F02M61/205—Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift
• • 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
• • 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
  • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
  • F02M61/10—Other injectors with elongated valve bodies, i.e. of needle-valve type
• • 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
  • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
  • F02M61/10—Other injectors with elongated valve bodies, i.e. of needle-valve type
  • F02M61/12—Other injectors with elongated valve bodies, i.e. of needle-valve type characterised by the provision of guiding or centring means for valve bodies
• • 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
  • 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
  • F02M2547/001—Control chambers formed by movable sleeves
• • 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
  • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
  • F02M61/042—The valves being provided with fuel passages

Definitions

• the invention is based on a fuel injection valve for internal combustion engines, as is known from published patent application DE 100 24 703 AI.
• a fuel injection valve has a housing with an inlet space in which a valve needle is arranged to be longitudinally displaceable. Through its longitudinal movement, the valve needle interacts with a valve seat and thereby opens and closes at least one injection opening, which is the injection of
• the fuel is supplied to the inlet space via an inlet channel and flows through the annular space, which is formed between the wall of the inlet space and the valve needle, in the direction of the injection openings when the valve needle has lifted off the valve seat.
• the known fuel injection valve is a so-called stroke-controlled system, in which a high fuel pressure is always present in the inlet space.
• the valve needle is acted upon by the fuel pressure in a control chamber and thereby experiences a closing force which is countered by an opening force which is caused by the
• Fuel pressure in the inlet area acts on the valve needle.
• the valve needle opens or returns to its closed position.
• valve needle In the known fuel injection valve, the valve needle is guided with a central guide area in the inlet space, the fuel flow to the injection openings being ensured by side grindings on the valve needle.
• the flow cross-section of these cuts is selected so that there is sufficient throttling of the fuel flow.
• the known fuel injection valve has the disadvantage that the injection characteristic of the injection valve depends very sensitively on the size of the throttles that are formed by the cuts on the valve needle. Even very small manufacturing tolerances in this area lead to a change in the injection behavior, which leads to a large scatter from the injection nozzle to the injection nozzle and thus to an uneven injection behavior in the different pistons of the internal combustion engine.
• a small passage cross section in the area of the ground sections has the disadvantage that this leads to pressure fluctuations in the inlet space when the fuel injection valve closes. Since the passage cross section in the area of the ground sections is relatively small, the fuel must have a high speed in this area in order to supply a sufficient amount to the injection openings.
• the fuel injection valve according to the invention with the characterizing features of patent claim 1 has the advantage over the fact that the fuel injection valve is relatively insensitive to manufacturing tolerances and has less wear in the area of the valve seat.
• the injection behavior is insensitive to temperature fluctuations and fuel-viscosity fluctuations.
• a throttle point is formed on the inlet channel, which feeds fuel into the inlet chamber, which represents the smallest flow cross-section with respect to the fuel flow from the inlet channel to the injection openings. This allows the grindings on the
• Passage cross-section formed larger, which significantly reduces the sensitivity to manufacturing tolerances and there leads to a reduction in the kinetic energy of the fuel. The latter in turn leads to a reduction in pressure vibrations and thus wear on the valve seat.
• the flow cross section at the passage cross section which is formed in the filling area of the valve needle, is two to ten times larger than the flow cross section at the throttle point.
• the passage cross section in the guide region of the valve needle is formed by two to six cuts on the valve needle, which are preferably arranged uniformly distributed over the circumference. Depending on the required flow resistance, the passage cross-section can be adjusted via the number of cuts, without the mechanical stability of the valve needle suffering.
• the passage cross section on the valve needle is dimensioned such that the kinetic energy of the fuel when the valve needle is placed on the valve seat only triggers weak pressure vibrations in the annular space, that is to say in the inlet space, which do not cause wear on the valve seat. If the kinetic energy in the area of the passage cross-section is low enough, the intensity of the pressure vibrations remains below a critical threshold, which does not cause any noteworthy deformation of the housing and therefore also no additional wear.
• Figure 2 shows a cross section through the fuel injector along the line labeled II-II.
• FIG. 1 shows a longitudinal section through a fuel injection valve according to the invention.
• the fuel injection valve has a housing 1, which comprises a valve body 2, a throttle disc 3 and a holding body 5, which are pressed against one another in this order by a clamping nut 7.
• An inlet chamber 12 is formed in the valve body 2, which essentially has the shape of a stepped bore.
• the inlet chamber 12 is delimited at its end on the combustion chamber side by a conical valve seat 20, from which a plurality of injection openings 22 emanate, which open into the combustion chamber of the internal combustion engine in the installed position of the fuel injection valve.
• a piston-shaped valve needle 18 is arranged in the inlet space 12 and is guided in a central guide section 19 on the wall of the inlet space 12.
• the valve needle 18 has at its end on the valve seat side an essentially conical valve sealing surface 23 with which it cooperates with the valve seat 20 for opening and closing the injection openings 22.
• An annular space 15 is formed between the valve needle 18 and the wall of the inlet space 12, through which the fuel detects the injection Openings 22 flows.
• the inlet chamber 12 is filled via an inlet channel 10 with fuel under high pressure, which is formed in the holding body 5 and in the throttle disc 3 and the other end of which is connected to a high-pressure fuel source, not shown in the drawing.
• the valve needle 18 At its end facing away from the valve seat, the valve needle 18 is surrounded by a sleeve 24 which, together with the throttle disk 3, delimits a control chamber 40 which is connected to the inlet channel 10 via an inlet throttle 35.
• a closing spring 28 is arranged under pressure, which presses the sleeve 24 against the throttle disk 3 on the one hand and on the other hand a closing force on the valve needle 18 in the direction of the valve seat 20 exercises.
• the valve needle 18 is held in contact with the valve seat 20 in the absence of further forces, so that in this case, for example when the internal combustion engine is switched off, the injection openings 22 remain closed.
• a control valve 32 is formed in the holding body 5 and comprises a control valve member 33 in a control valve chamber 34.
• the control valve chamber 34 is connected to the control chamber 40 via an outlet throttle 37 and, moreover, to the inlet chamber 12 via an additional throttle 38.
• the control valve member 33 is moved longitudinally via an actuator (not shown in the drawing) and thus connects the control chamber 34 to a leakage oil chamber 41 is formed in the holding body 5 and in which there is always a low fuel pressure. If the control valve member 33 is in its position facing away from the valve needle 18, the inflow of the control valve chamber 34 to the leakage oil chamber 41 is interrupted while the additional throttle 38 is opened. If, on the other hand, the control valve member 33 is in contact with the throttle disk 3, the additional throttle 38 is closed and the connection to the leakage oil chamber 41 is opened. The connection of the control valve chamber 34 to the control chamber 40 always remains open.
• FIG. 2 shows a cross section through the fuel injection valve along the line II-II.
• four bevels 44 are formed, which form four individual channels between the wall of the inlet space 12 and the valve needle 18, which together represent a passage cross section 46.
• the bevels 44 are designed so that the passage cross section 46 only forms a low flow resistance for the fuel flowing into the injection openings 22.
• a throttle point 30 is arranged in the throttle disc 3, which represents the smallest flow cross section for the entire fuel flow. Except for the other unavoidable flow losses, the throttling of the fuel flow takes place exclusively at the throttle point 30, which has a flow cross-section that is 2 to 10 times smaller than that of the passage cross-section 46.
• the fuel injection valve functions as follows: At the beginning of the injection, the control valve member 33 is in its first switching position, in which the inflow from the control chamber 34 to the leakage oil chamber 41 is interrupted. About the inlet throttle 35 and the additional throttle 38 prevails in the control valve chamber 34 and in the control chamber 40, the same high fuel pressure as in the inlet channel 10 and in
• the pressure increase in the area of the valve sealing surface 23 is therefore less steep and only causes a relatively slow increase in the opening force. Since only a very small amount of fuel is to be injected, the control valve 32 is actuated again before the valve needle 18 abuts the throttle valve. disc 3 is. The control valve member 33 again moves away from the throttle disc 3 and closes the connection of the control valve chamber 34 with the leakage oil chamber 41.
• the pressure in the control chamber 40 increases via the inlet throttle 35 and the inlet throttle 38, which additionally fuel via the outlet throttle 37 in the control chamber 40 brings very quickly back on and causes a closing force on the valve needle 18, which brakes its opening movement and accelerates it again in the direction of the valve seat 20 until it sits again on the valve seat 20 and closes the injection openings 22.
• Front side of the valve needle 18 acts to reach a maximum of the area of the front side multiplied by the pressure of the fuel in the control chamber 40, which corresponds to the pressure in the inlet channel 10. If the fuel flow between the inlet duct 10 and the valve seat 20 is not throttled, the hydraulic opening force which acts on the valve needle 18 also has this value when the injection openings 22 are fully open. As a result, only the relatively low biasing force of the closing spring 28 would be available as the resulting closing force. By throttling the fuel flow at the throttling point 30, the hydraulic opening force on the valve needle 18 is slightly reduced and the resulting closing force is increased. This results in a significantly higher closing speed of the valve needle 18 and thus a more precisely defined closing time of the injection valve.
• the fuel In the area of the connections 44, the fuel is in motion as a result of the injection process, as in the entire inlet space 12, and has a certain kinetic energy.
• the fuel column which is located in the annular space 15 is braked abruptly, which converts the kinetic energy into compression work and finally leads to pressure oscillations in the annular space 15. Due to the relatively large passage cross section 46 in the annular space 15, which is approximately 2 mm 2 , the kinetic energy is in
• the area of the bevels 44 is so small that the pressure vibrations do not lead to any significant expansion of the valve body 2 and thus to no additional wear on the valve seat 20.
• the throttle point 30 is formed further upstream in the inlet channel 10, depending on which position is advantageous in terms of flow and production technology. It can also be provided that instead of four grindings 44 in the guide area 19 two, three, five or six grindings 44 are provided which provide a corresponding passage cross section 46.
• Guide region 19 of the valve needle 18 is simply cylindrical.

Applications Claiming Priority (2)

Publications (1)

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ID=34353326

Family Applications (1)

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Cited By (2)

Families Citing this family (4)

Citations (8)

• 2003
  • 2003-10-06 DE DE2003146212 patent/DE10346212A1/de not_active Withdrawn
• 2004
  • 2004-08-13 WO PCT/DE2004/001811 patent/WO2005045233A1/de active Application Filing

Patent Citations (8)

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