EP1162364B1 - Kraftstoffeinspritzvorrichtung - Google Patents

Kraftstoffeinspritzvorrichtung Download PDF

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Publication number
EP1162364B1
EP1162364B1 EP20010113920 EP01113920A EP1162364B1 EP 1162364 B1 EP1162364 B1 EP 1162364B1 EP 20010113920 EP20010113920 EP 20010113920 EP 01113920 A EP01113920 A EP 01113920A EP 1162364 B1 EP1162364 B1 EP 1162364B1
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EP
European Patent Office
Prior art keywords
fuel injection
fuel
pressure
passage
taper portion
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.)
Expired - Lifetime
Application number
EP20010113920
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English (en)
French (fr)
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EP1162364A1 (de
Inventor
Takafumi Yamada
Kiyoshi c/o TOYOTA Jidosha Kabushiki Naiki
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Toyota Motor Corp
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Toyota Motor Corp
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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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/02—Conduits between injection pumps and injectors, e.g. conduits between pump and common-rail or conduits between common-rail and injectors
    • F02M55/025—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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/004—Joints; Sealings
    • F02M55/005—Joints; Sealings for high pressure conduits, e.g. connected to pump outlet or to injector inlet
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/04—Means for damping vibrations or pressure fluctuations in injection pump inlets or outlets
    • 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
    • F02M2200/28—Details of throttles in fuel-injection apparatus
    • 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

Definitions

  • the present invention relates to a fuel injection apparatus and, more particularly, to a fuel injection apparatus that distributes fuel from a pressure accumulating chamber (common rail) storing high-pressure fuel to individual fuel injection valves and that intermittently performs fuel injection from the fuel injection valves, for example, a common rail type fuel injection apparatus of an internal combustion engine.
  • a pressure accumulating chamber common rail
  • a common rail type fuel injection apparatus in which a pressure accumulating chamber (common rail) for storing high-pressure fuel is provided and the common rail is connected to individual fuel injection valves so as to distribute high-pressure fuel from the common rail to each fuel injection valve.
  • the pressure in the common rail i.e., pressure of injection from each fuel injection valve
  • the common rail type fuel injection apparatuses are able to maintain high fuel injection pressure even during low-speed operation of the engine, and are able to accomplish good atomization of injected fuel even during low-speed engine operation, thereby achieving the advantage of improving the combustion state of the engine.
  • fuel injection is performed at high pressure (e.g., 100 to 150 MPa), so that each fuel injection valve undergoes great pressure fluctuations at the start and end of fuel injection.
  • pressure fluctuations propagate to the common rail via fuel supplying pipes connecting the fuel injection valves and the common rail, and are reflected in a complicated fashion, thereby fluctuating the injection pressure of the fuel injection valves. For example, if pressure fluctuations occurring in a fuel injection valve at the end of a fuel injection are reflected from the common rail, and return to the fuel injection valve, the pressure in the fuel supplying pipes pulsates despite the end of fuel injection, until the pressure fluctuations attenuate.
  • the main fuel injection may be started before the pressure fluctuations in the fuel supplying pipe caused by the pilot fuel injection attenuate in some cases, so that the amount of injection of the main fuel injection and the injection timing thereof may become inaccurate.
  • each of fuel supplying pipe connecting portions of the common rail to the individual fuel injection valves is provided with a flow passage area-reduced portion, as in an orifice or the like. Due to the passage resistance of each orifice, pressure pulsation is attenuated within a short period of time.
  • an orifice diameter As possible, if the orifice diameter is set small, the resistance of the orifice becomes great, thus giving rise to a problem of reduction in the amount of flow of fuel from the common rail to each fuel injection valve. That is, the setting of the orifice diameter smaller than a certain diameter inconveniently reduces the injection pressure during fuel injection, thereby giving rise to a problem of a prolonged duration of fuel injection for injecting a needed amount of fuel.
  • the orifice diameter can be reduced only to a certain level, thereby giving rise to a problem of an insufficient attenuation of pressure pulsation becomes insufficient.
  • Japanese Patent Application Laid-Open No. HEI 9-112380 proposes that fluidic diodes be disposed in fuel pipes connecting the common rail and the individual fuel injection valves.
  • a fluidic diode described in Japanese Patent Application Laid-Open No. HEI 9-112380 has a large-diameter hole, a contracted pipe-like taper hole, an orifice hole that are continuously formed in that order from the common rail side to the fuel injection valve side.
  • the fluidic diode described in the aforementioned laid-open application utilizes a phenomenon that fuel flowing from the common rail side toward the fuel injection valve side flows from the large-diameter hole into the orifice hole through the contracted pipe-like taper hole, and therefore undergoes a relatively small flow resistance whereas flows of fuel from the fuel injection valve side to the common rail side due to the pressure pulsation in each fuel injection valve directly flow into the orifice hole, and therefore undergo a relatively great flow resistance, so as to attenuate only the pressure pulsation within a short period of time without reducing the supply of fuel from the common rail to the fuel injection valves.
  • the invention has been accomplished in view of the aforementioned problems. It is an object of the invention to provide a fuel injection apparatus that, when applied to a common rail type fuel injection apparatus, is able to maintain a sufficiently small resistance of flow of fuel from the common rail side to the fuel injection valve side and to sufficiently increase the resistance of flow of fuel from the fuel injection valve side to the common rail side.
  • a fuel injection apparatus having a pressure accumulating chamber that stores a pressurized fuel, and a fuel injection valve that is connected to the pressure accumulating chamber and that injects the fuel supplied from the pressure accumulating chamber, includes: a constricted passage that is formed in the passage extending from the pressure accumulating chamber to the fuel injection valve and that has a passage sectional area that is smaller than an area of the ejection opening; a tubular first taper portion that is connected to the constricted passage, and that is formed upstream of the constricted passage, and that tapers in a direction from the pressure accumulating chamber toward the constricted passage at a first predetermined inclination angle; and a tubular second taper portion that is connected to the constricted passage, and that is formed downstream of the constricted passage, and that tapers in a direction from the fuel injection valve toward the constricted passage at a second predetermined inclination angle.
  • the second predetermined inclination angle ( ⁇ ) of the second taper portion is
  • the fuel supplying passage is provided with a constriction, and a taper portion is formed at the inlet side (common rail side) of the constriction. Another taper portion is formed at the outlet side (fuel injection valve side) of the constriction.
  • the inclination angle of a wall surface of the outlet-side taper portion (second taper portion) is set smaller than the inclination angle of a wall surface of the inlet-side taper portion (first taper portion).
  • the flow resistance at the inlet side of the passage increases because the flow of fuel into the constriction encounters a sharp narrowing of the passage at the inlet of the constriction.
  • the aforementioned related-art fluidic diode has a narrowed tube-like taper at the inlet of the passage wherein the flow resistance of fuel flowing into the constriction is reduced.
  • the outlet of the constriction is not provided with a taper portion. Therefore, as for the reverse flow (flow from the fuel injection valve toward the common rail), the flow into the constriction undergoes a sharp diameter reduction, thus increasing the flow resistance.
  • the fluidic diode achieves reduced resistance with respect to forward flow (flow from the common rail toward the fuel injection valve), and achieves increased resistance with respect to reverse flow (flow from the fuel injection valve toward the common rail).
  • the actual passage resistance of a fluid passing through a constriction greatly varies depending on the configuration of the outlet side of the constriction, as well as the configuration of the inlet side thereof. More specifically, if the passage sharply expands at the outlet side of the constriction, the sharp expansion of the passage causes greatly increased eddy loss, so that the passage resistance increases.
  • the related art exhibits an effect of reducing the pressure pulsation due to increased passage resistance in the reverse direction (from the fuel injection valve toward the common rail), the related art hardly reduces the passage resistance of flow in the forward direction (from the common rail side to the fuel injection valve side) in comparison with a construction in which only a simple constriction is provided. Therefore, the related art still has a problem of insufficient fuel supply to a fuel injection valve during a fuel injection period.
  • a taper portion is provided at the outlet side of the constriction, as well as the inlet-side taper portion. Furthermore, the outlet-side taper portion is formed so that the inclination angle of the wall surface (inclination angle of the taper) of the outlet-side taper portion is smaller than that of the inlet-side taper portion.
  • the inclination angle of the taper at the inlet side of the constriction is greater than the inclination angle of the outlet-side taper.
  • the constriction inlet-side taper functions as a constriction outlet-side taper with respect to flow in the reverse direction.
  • the inclination angle of the taper is great, the eddy loss caused by sharp passage expansion increases.
  • the constriction outlet-side taper is relatively gentle with respect to forward flow, so that there is no sharp passage expansion and the forward flow resistance becomes less.
  • the constriction inlet-side taper has a relatively great inclination, so that with respect to reverse flow, the sharp passage expansion at the outlet of the constriction increases the resistance.
  • the passage resistance with respect to flow in the forward direction of the fuel supplying passage (in the direction from the common rail toward the fuel injection valve) is considerably reduced, but the passage resistance with respect to flow in the reverse direction (in the direction from the fuel injection valve toward the common rail) is hardly reduced, in comparison with a construction in which only a simple constriction is provided.
  • the flow caused in the reverse direction in the passage by pressure fluctuation due to injection from the fuel injection valve is blocked by the great resistance, whereas the flow in the forward direction in the passage does not receive resistance.
  • the pressure fluctuation caused by fuel injection attenuates within a short time, and at the same time, sufficient amount of fuel is supplied to the fuel injection valve during a fuel injection period so that the fuel injection pressure decrease during fuel injection period is eliminated.
  • FIG. 1 is a diagram schematically illustrating a construction of an embodiment in which the fuel injection apparatus of the invention is applied to an automotive diesel engine.
  • an internal combustion engine 1 is a four-cylinder four-cycle diesel engine having four cylinders (#1 to #4).
  • the internal combustion engine 1 is equipped with fuel injection valves (10a to 10d) for injecting fuel directly into the cylinders (#1 to #4).
  • the fuel injection valves 10a-10d are connected to a common pressure accumulating chamber (common rail) 3 via high-pressure fuel pipes (fuel supply passages) 11a-11d.
  • the common rail 3 has functions of storing pressurized fuel supplied from a high-pressure fuel injection pump 5, and distributing high-pressure fuel stored therein to the fuel injection valves 10a-10d via the high-pressure fuel pipes 11a-11d.
  • the high-pressure fuel injection pump 5 is, for example, a plunger-type pump having a mechanism for adjusting the amount of ejection.
  • the high-pressure fuel injection pump 5 pressurizes fuel supplied form a fuel tank (not shown) to a predetermined pressure, and supplies pressurized pressure to the common rail 3.
  • the amount of fuel delivered from the pump 5 to the common rail 3 is feedback-controlled by an ECU 20 so that the pressure in the common rail 3 equals a target pressure. Therefore, the fuel pressure in the common rail 3 (i.e., the fuel injection pressure of the fuel injection valves) can be set to high pressure even during a low-speed engine operation.
  • the electronic control unit (ECU) 20 for controlling the engine is formed as a microcomputer having a known construction in which a read-only memory (ROM), a random access memory (RAM), a microprocessor (CPU), and input/output ports are interconnected by a bidirectional bus.
  • the ECU 20 controls the amount of ejection from the pump 5 so to perform a fuel pressure control of controlling the common rail 3 pressure to a target value determined in accordance with an engine operation condition.
  • the ECU 20 performs basic controls of the engine, such as a fuel injection control of controlling the fuel injection timing and the injection amount of main fuel injection by controlling the open valve timing and duration of the fuel injection valves 10a-10d, and the like.
  • the common rail 3 in this embodiment is provided with a fuel pressure sensor 27 for detecting the common rail fuel pressure.
  • an accelerator operation amount sensor 21 is provided near an accelerator pedal (not shown) of the engine 1 for detecting the amount of accelerator operation (the amount of depression of the accelerator pedal accomplished by an operating person).
  • a cam angle sensor 23 for detecting the rotation phase of a camshaft of the engine 1, and a crank angle sensor 25 for detecting the rotation phase of a crankshaft are provided as shown in FIG. 1.
  • the cam angle sensor 23 is disposed near the camshaft of the engine 1, and outputs a reference pulse at every 720 degrees in terms of crank rotation angle.
  • the crank angle sensor 25 is disposed near the crankshaft of the engine 1, and outputs a crank angle pulse at every predetermined crank rotation angle (e.g., every 15 degrees).
  • the ECU 20 calculates the engine revolution speed from the frequency of the crank rotation angle pulse signal input from the crank angle sensor 25. Based on the engine revolution speed and the accelerator operation amount signal input from the accelerator operation amount sensor 21, the ECU 20 calculates the fuel injection timing and the fuel injection amount of each of the fuel injection valves 10a-10d.
  • fuel injection valves 10 When one of the fuel injection valves 10a-10d (hereinafter, collectively referred to as “fuel injection valves 10") opens, fuel flows into the fuel injection valve from the common rail 3 via a corresponding one of the high-pressure fuel pipes 11a-11d (hereinafter, collectively referred to as “high-pressure fuel pipes 11.
  • high-pressure fuel pipes 11a-11d hereinafter, collectively referred to as "high-pressure fuel pipes 11.
  • Portions of the pressure waves propagate from the inside of the common rail 3 into the other high-pressure fuel pipes, and a portion of the pressure waves is reflected at the entrance of the common rail 3, and propagates back to the fuel injection valve 10. Therefore, when the fuel injection stops, reflected pressure waves fluctuate the fuel supplying pressure of the fuel injection valve.
  • the above-described problem is solved by inserting an orifice piece 100 in each high-pressure fuel pipe 11 (more precisely, a connecting portion between each high-pressure fuel pipe 11 and the common rail 3) as shown in FIG. 2.
  • the orifice piece 100 has a constriction that has taper portions at opposite sides.
  • the orifice piece 100 is provided between the common rail 3 and the high-pressure fuel pipe 11.
  • a fuel passage 3a is formed in the common rail 3. Since high-pressure fuel (e.g., about 100 to 150 MPa) is stored in the common rail 3, it is preferable in terms of strength of the common rail that a through-hole formed in the common rail 3 have a hole diameter that is reduced as much as possible. Therefore, in this embodiment, the diameter of the fuel passage 3a formed in a wall of the common rail is set to a small value.
  • the fuel passage 3a also functions as a constriction in the fuel supplying path from the common rail to the fuel injection valve.
  • the orifice piece 100 is provided to prevent pressure fluctuation in the high-pressure fuel pipe 11.
  • the orifice piece 100 in this embodiment has a small-diameter end 103 that is fitted into the high-pressure fuel pipe 11, and a large-diameter end 105 that is received by an orifice piece connecting portion of the common rail 3.
  • the high-pressure fuel pipe 11 and the common rail 3 are firmly interconnected by a fitting (not shown), with the orifice piece 100 being disposed between the high-pressure fuel pipe 11 and the common rail 3.
  • the orifice piece 100 has a fuel passage 110 that is formed by an inlet-side taper portion 111, a small-diameter constricted portion 113, and an outlet-side taper portion 115.
  • FIG. 3 is an enlarged view illustrating the configuration of the fuel passage 110.
  • the inlet-side taper portion 111 is formed at the inlet side (common rail side) of the small-diameter constricted portion 113.
  • the inlet-side taper portion 111 has a taper tubular shape in which the bore gradually decreases in the forward flow direction (i.e., the direction from the common rail toward the fuel injection valve).
  • the inclination angle of the wall surface of the inlet-side taper portion 111 is set to at least 120 degrees.
  • the outlet-side taper portion 115 is formed on the outlet side (fuel injection valve side) of the small-diameter constricted portion 113.
  • the outlet-side taper portion 115 has a taper tubular shape in which the bore gradually increases in the direction opposite to the forward flow direction.
  • the inclination angle of the wall surface of the outlet-side taper portion 115 (indicated by ⁇ in FIG. 3) may be any angle in the range of 0 ⁇ ⁇ ⁇ 120 degrees.
  • the wall surface inclination angle of the outlet-side taper portion 115 is preferably 5 to 10 degrees and, more preferably, 7 to 8 degrees (about 7.5 degrees) as in the embodiment.
  • the wall surface inclination angle of the outlet-side taper portion 115 is smaller than the wall surface inclination angle of the inlet-side taper portion 111.
  • the outlet-side taper portion 115 is provided at the outlet of the small-diameter constricted portion 113 as shown in FIG. 3, the fuel passage gradually expands from the small-diameter constricted portion 113 to the high-pressure fuel pipe 11 via the inlet-side taper portion 111, so that the loss caused by sharp expansion of passage at the outlet is reduced.
  • FIG. 4 is a diagram illustrating changes in the pressure loss of flow of fuel through the outlet-side taper portion 115 where the expansion angle ⁇ of the outlet-side taper portion 115 is changed. As indicated in FIG. 4, the pressure loss increases as the expansion angle ⁇ is increased.
  • the expansion angle of the outlet-side taper portion 115 is set to ⁇ 1 at which the pressure loss practically becomes a minimum.
  • This angle has empirically been found to be about 7.5 degrees. This configuration practically minimizes the flow resistance of forward flow through the passage 110 of the orifice piece 100.
  • the expansion angle ⁇ of the inlet-side taper portion 111 is set to a value that is equal to or greater than the value ⁇ 2.
  • the value ⁇ 2 has been empirically found to be about 120 degrees.
  • the expansion angle ⁇ of the inlet-side taper portion 111 is set as in ⁇ ⁇ 120 degrees ( ⁇ ⁇ 180 degrees).
  • the purpose of setting the expansion angle of the inlet-side taper portion 111 to at least ⁇ 2 is to increase the pressure loss of flow through the passage 110 in the opposite direction (direction from the fuel injection valve side to the common rail side). That is, the inlet-side taper portion 111 avoids the sharp diameter reduction of passage and thereby reduces the pressure loss with respect to forward flow.
  • the inlet-side taper portion 111 functions as an outlet-side taper portion, and increases the pressure loss. Namely, the pressure loss of reverse flow through the passage 110 is increased by setting an increased expansion angle ⁇ of the taper portion. More specifically, by setting the expansion angle ⁇ of the inlet-side taper portion 111 to at least 120 degrees, the pressure loss of reverse flow can be increased while the effect of reducing the pressure loss of forward flow is maintained.
  • the orifice piece 100 of the embodiment produces the pressure loss due to the sharp passage expansion of the inlet-side taper portion 111 in addition to the pressure loss caused by the small-diameter constricted portion 113, with respect to flow through the passage 110 in the reverse direction (the direction from the fuel injection valve toward the common rail).
  • the passage 110 provides great resistance with respect to reverse flow.
  • the inlet-side taper portion 111 reduces the pressure loss caused by the sharp diameter reduction of passage, and the outlet-side taper portion 115 considerably reduces the pressure loss caused by sharp passage expansion. Therefore, with respect to forward flow, the passage 110 causes only a small resistance that is about equal to the conduit resistance of the small-diameter constricted portion 113.
  • the orifice piece 100 exhibits a characteristic in which the flow resistance is small with respect to forward flow, and is great with respect to reverse flow.
  • FIGS. 5A and 5B illustrate effects of the orifice piece 100 of the embodiment based on experiment results.
  • FIG. 5A indicates changes in the fuel injection rate of a fuel injection valve 10 during a fuel injection period.
  • FIG. 5B indicates changes in the fuel pressure at the inlet of a fuel injection valve during the same fuel injection period as in FIG. 5A.
  • a curve I indicated by a one-dot chain line represents a case where the high-pressure fuel pipe 11 is not provided with a constriction (i.e., where only the fuel passage 3a extending through the wall of the common rail 3 is present as a small-diameter portion within the fuel supplying path)
  • a curve II indicated by a solid line represents a case where the orifice piece 100 of the embodiment is provided
  • a curve III indicated by a broken line represents a case where the high-pressure fuel pipe is provided with only a constriction (only a small-diameter constriction without tapered end portions).
  • FIG. 5A changes in the injection rate in the case of the high-pressure fuel pipe 11 without a constriction and changes in the injection rate in the case of the orifice piece 100 are substantially the same, and are indicated by the solid line. Furthermore, in FIGS. 5A and 5B, a point A indicates a fuel injection start time point (time at which the fuel injection valve opens), and a point B indicates a fuel injection end time point (time at which the fuel injection valve closes).
  • the amount of fuel that flows into the fuel injection valve exhibits substantially no decrease during a later stage of the fuel injection period due to effect of provision of the outlet-side taper portion 115, in comparison with the case (curve I) where no constriction is provided.
  • the fuel pressure exhibits only a slight decrease (FIG. 5B).
  • the fuel injection rate changes substantially in the same manner as in the case (curve I) where no constriction is provided, and no reduced fuel injection rate is exhibited during the late stage of the fuel injection period.
  • the inlet-side taper portion 111 operates as a great resistance with respect to reverse flow as mentioned above, the amplitude of pressure pulsation after the end of fuel injection is reduced, and the pressure pulsation attenuates within a reduced time (FIG. 5B), in comparison with the case where no constriction is provided.
  • the pressure pulsation after fuel injection ends affects the amount of fuel injection and the injection timing of the next fuel injection in some cases as mentioned above.
  • a diesel engine that performs pilot fuel injection prior to main fuel injection in particular, there are cases where the fuel pressure pulsation after the end of pilot fuel injection affects the injection amount and the injection timing of the subsequent main fuel injection. Therefore, the fuel pressure pulsation after fuel injection ends needs to be attenuated quickly.
  • FIGS. 6A and 6B are diagram illustrating the influences that pressure pulsation has on the amount of fuel injection in a case where pilot fuel injection is performed.
  • FIG. 6A indicates pilot fuel injection of an amount Q1 of fuel and, after an interval T, main fuel injection of a predetermined length of time.
  • FIG. 6B indicates changes in the total fuel injection amount (i.e., the total amount Q1 + Q2 of the pilot fuel injection amount Q1 and the main fuel injection amount Q2) with changes in the internal T.
  • a curve I indicated by a one-dot chain line represents a case where the high-pressure fuel pipe 11 is not provided with a constriction
  • a curve II indicated by a solid line represents a case where the orifice piece 100 of the embodiment is provided
  • a curve III indicated by a broken line represents a case where the high-pressure fuel pipe is provided with only a constriction without tapered end portions, as in FIGS. 5A and 5B.
  • the fuel pressure pulsation after pilot fuel injection ends is great, the width of fluctuations in the total fuel injection amount with changes in the interval T becomes a greatest.
  • the widths of fluctuations in the total fuel injection amount are less than in the case of the curve I. Therefore, it should be understood that the provision of the orifice piece 100 of the embodiment prevents reduction in the fuel injection rate during the fuel injection period (FIG. 5A), and reduces the fluctuations in the amount of fuel injection occurring with changes in the interval T between pilot fuel injection and main fuel injection, and thereby allows accurate fuel injection control.
  • Embodiments of the invention other than the foregoing embodiment will be described with reference to FIGS. 7 and 8.
  • the orifice pieces 100 are inserted in the connecting portions between the common rail 3 and the high-pressure fuel pipes 11, and are fixed via pipe fittings, an independent orifice piece 100 is not provided in the embodiments.
  • an inlet-side taper portion 111, a small-diameter constricted portion 113 and an outlet-side taper portion 115 are formed in the wall of a common rail 3.
  • an inlet-side taper portion 111, a small-diameter constricted portion 113 and an outlet-side taper portion 115 are formed in a pipe fitting (union) 80 used to interconnect the common rail 3 and the high-pressure fuel pipe 11.
  • the taper expansion angles of the taper portions 111, 115 are set to the same values as in the embodiment shown in FIGS. 2 and 3.
  • the embodiments shown in FIGS. 7 and 8 do not need a separate orifice piece 100, so that the number of component parts of the entire apparatus can be reduced, and the assembly process can be simplified.
  • the orifice piece 100 is inserted in a connecting portion between the common rail 3 and the high-pressure fuel pipe 11 for supplying fuel pressure from the common rail 3 to a fuel injection valve.
  • the orifice piece has a fuel passage formed by the inlet-side taper portion 111, the small-diameter constricted portion 113 and the outlet-side taper portion 115.
  • the inclination angle of the wall surface of the outlet-side taper portion is set smaller than the inclination angle of the wall surface of the inlet-side taper portion.
  • the provision of the outlet-side taper portion with a small inclination angle prevents an increase in the resistance of flow of fuel in the direction from the common rail toward the fuel injection valve.
  • the provision of the inlet-side taper portion with a large inclination angle increases the resistance of flow of fuel caused by pressure pulsation from the fuel injection valve toward the common rail.
  • the invention When the invention is applied to a common rail type fuel injection apparatus, it becomes possible to maintain a sufficiently small resistance of flow of fuel from the common rail side to the fuel injection valve side, and to sufficiently increase the resistance of flow of fuel from the fuel injection valve side to the common rail side.
  • the invention achieves an advantage of improving the precision of the fuel injection control.
  • Orifice pieces (100) are disposed in connecting portions between a common rail (3) and high-pressure fuel pipes (11) that supply high-pressure fuel to fuel injection valves (10a-10d).
  • Each orifice piece (100) has, in its interior, a fuel passage that is formed by an inlet-side taper portion (111), a small-diameter constricted portion (113), and an outlet-side taper portion (115).
  • the inclination angle of a wall surface of the outlet-side taper portion (115) is set smaller than the inclination angle of a wall surface of the inlet-side portion (111).
  • outlet-side taper portion (115) prevents an increase in the resistance of flow of fuel in the direction from the common rail (3) toward a corresponding one of the fuel injection valves (10a-10d).
  • the provision of the inlet-side taper portion (111) with a great inclination angle increases the fuel flow resistance due to pressure pulsation from the corresponding one of the fuel injection valves (10a-10d) toward the common rail.

Claims (6)

  1. Brennstoffeinspritzeinrichtung, mit:
    einer Drücksammelkammer (3), die unter Druck stehenden Brennstoff speichert und den unter Druck stehenden Brennstoff über eine Ausspritzöffnung (105) zuführt;
    einem Brennstoffeinspritzventil (10a-10d), das den Brennstoff erhält, der über einen Durchgang (11) von der Drucksammelkammer (3) zugeführt wird, und das den Brennstoff einspritzt;
    einem verengten Durchgang (113), der in dem Durchgang (11) ausgebildet ist, der sich von der Drucksammelkammer (3) zu dem Brennstoffeinspritzventil (10a-10d) erstreckt, und der einen Durchgangssektionsbereich hat, der kleiner als ein Bereich der Ausspritzöffnung (105) ist;
    einem röhrenförmigen ersten konischen Abschnitt (111), der mit dem verengten Durchgang (113) verbunden ist, und der stromaufwärts des verengten Durchgangs (113) ausgebildet ist, und der in einer Richtung von der Drucksammelkammer (3) in Richtung auf den verengten Durchgang (113) mit einem ersten vorbestimmten Neigungswinkel (α) konisch verläuft;
    gekennzeichnet durch
       einen röhrenförmigen zweiten konischen Abschnitt (115), der mit dem verengten Durchgang (113) verbunden ist, und der stromabwärts des verengten Durchgangs (113) ausgebildet ist, und der von dem Brennstoffeinspritzventil (10a-10d) in einer Richtung auf den verengten Durchgang (113) mit einem zweiten vorbestimmten Neigungswinkel (β) konisch verläuft;
       wobei der zweite vorbestimmte Neigungswinkel (β) des zweiten konischen Abschnitts (11) kleiner als der des ersten vorbestimmten Neigungswinkel (α) des ersten konischen Abschnitts (111) ist.
  2. Brennstoffeinspritzeinrichtung gemäß Anspruch 1, wobei eine Neigungsfläche des zweiten konischen Abschnitts derart ausgebildet ist, dass ein Druckverlust, der während des Brennstoffstroms vom dem verengten Durchgang (113) zu dem Brennstoffeinspritzventil (10a-10d) auftritt, im Wesentlichen gleich sowohl an der stromaufwärtigen Seite des zweiten konischen Abschnitts (115) als auch an der stromabwärtigen Seite des zweiten konischen Abschnitts (115) ist.
  3. Brennstoffeinspritzeinrichtung gemäß Anspruch 1 oder 2,
       wobei der erste vorbestimmte Neigungswinkel (α), der durch eine geneigte Fläche begrenzt ist, die symmetrisch um eine Mittelpunktsachse des verengten Durchgangs (113) ausgebildet ist, zumindest 120° beträgt, und
       wobei der zweite vorbestimmte Neigungswinkel (β), der durch eine geneigte Fläche begrenzet ist, die symmetrisch um die Mittelpunktsachse des verengten Durchgangs (113) ausgebildet ist, 7 bis 8° beträgt.
  4. Brennstoffeinspritzeinrichtung gemäß einem oder jedem der Ansprüche 1 bis 3, wobei eine Bauteil (100), das einstückig den ersten konischen Abschnitt (111) ausbildet, der verengte Durchgang (113) und der zweite konische Abschnitt (115) zwischen der Drucksammelkammer (3) und dem Durchgang (11), der den Brennstoff zu dem Brennstoffeinspritzventil (10a-10d) transportiert, angeordnet sind.
  5. Brennstoffeinspritzeinrichtung gemäß Anspruch 4, wobei das Bauteil (100) eine Funktion einer Befestigung ausführt, um die Drucksammelkammer (3) und den Durchgang (11) zu verbinden.
  6. Brennstoffeinspritzeinrichtung gemäß einem oder jedem der Ansprüche 1 bis 3, wobei der erste konische Abschnitt (111), der mit der Ausspritzöffnung (105) verbunden ist, der verengte Durchgang (113) und der zweite konische Abschnitt (115) innerhalb einer Wand ausgebildet sind, die die Drucksammelkammer (3) ausbildet.
EP20010113920 2000-06-08 2001-06-07 Kraftstoffeinspritzvorrichtung Expired - Lifetime EP1162364B1 (de)

Applications Claiming Priority (2)

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JP2000177171 2000-06-08
JP2000177171A JP3558008B2 (ja) 2000-06-08 2000-06-08 燃料噴射装置

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EP1162364B1 true EP1162364B1 (de) 2002-09-25

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DE10217592A1 (de) * 2002-04-19 2003-11-06 Siemens Ag Injektor zur Einspritzung von Kraftstoff
US6886537B2 (en) * 2002-07-04 2005-05-03 Denso Corporation Accumulation type fuel injection system for engine
FR2845129B1 (fr) 2002-09-30 2006-04-28 Delphi Tech Inc Insert du type diode fluidique pour attenuer des ondes de pression, et rail commun equipe de tels inserts
US6925989B2 (en) 2003-08-18 2005-08-09 Visteon Global Technologies, Inc. Fuel system having pressure pulsation damping
DE102004030266A1 (de) 2004-06-23 2006-01-12 Robert Bosch Gmbh Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine
DE102004041238A1 (de) * 2004-08-26 2006-03-02 Robert Bosch Gmbh Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine
US8569477B2 (en) 2005-02-11 2013-10-29 Life Technologies As Method for isolating nucleic acids comprising the use of ethylene glycol multimers
DE102005026993A1 (de) * 2005-06-10 2006-12-14 Robert Bosch Gmbh Hochdruckspeicherraumkörper mit Hochdruckdrosseln
JP4572843B2 (ja) * 2005-10-13 2010-11-04 株式会社デンソー コモンレール式燃料噴射システムの制御装置
DE102005057951A1 (de) 2005-12-05 2007-06-06 Robert Bosch Gmbh Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine
JP5178176B2 (ja) * 2007-12-17 2013-04-10 臼井国際産業株式会社 高圧燃料噴射管の接続頭部構造

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US4356091A (en) * 1980-10-06 1982-10-26 Caterpillar Tractor Co. Filtering and dampening apparatus
JP3503784B2 (ja) 1995-10-13 2004-03-08 株式会社デンソー 蓄圧式燃料噴射装置
JPH09303232A (ja) * 1996-05-09 1997-11-25 Toyota Motor Corp コモンレール式ディーゼルエンジンの噴射管接続構造
JPH09317599A (ja) * 1996-05-22 1997-12-09 Usui Internatl Ind Co Ltd コモンレールおよびその製造方法

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JP2001349261A (ja) 2001-12-21
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DE60100030T2 (de) 2003-02-06
EP1162364A1 (de) 2001-12-12

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