EP0582993B1 - Accumulator fuel injection apparatus - Google Patents
Accumulator fuel injection apparatus Download PDFInfo
- Publication number
- EP0582993B1 EP0582993B1 EP19930112796 EP93112796A EP0582993B1 EP 0582993 B1 EP0582993 B1 EP 0582993B1 EP 19930112796 EP19930112796 EP 19930112796 EP 93112796 A EP93112796 A EP 93112796A EP 0582993 B1 EP0582993 B1 EP 0582993B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- nozzle
- pressure
- piston
- end side
- control chamber
- 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
Links
Images
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
- 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
- F02M45/083—Having two or more closing springs acting on injection-valve
-
- 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
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
Definitions
- the present invention relates to an accumulator fuel injection apparatus according to the preamble of claim 1 and, more particularly, to a fuel injection apparatus for a diesel engine, which facilitates setting of an amount of pre-lift of a nozzle needle.
- a generic accumulator fuel injection apparatus As a fuel injection apparatus for a diesel engine, a generic accumulator fuel injection apparatus has been disclosed, for example, in the US-A-5 156 132 corresponding to the EP-A-393 590, which comprises common accumulator piping called a common rail for accumulating high-pressure fuel, and an injector for injecting the fuel.
- a nozzle needle for opening and closing an injection bore is slidably arranged within the injector.
- the nozzle needle defines a back-pressure chamber for retaining fuel pressure which acts on the nozzle needle. Pressure within the back-pressure chamber is so controlled as to be switched to fuel pressure on the high-pressure side and fuel pressure on the low-pressure side by a three-way electromagnetic valve.
- the high-pressure fuel supplied from the accumulator piping is injected from the injection bore.
- pre-lift of a nozzle needle is so set as to achieve boot-type injection which is such an injection rate that an amount of injection at initial time of injection is constant, the amount of injection is made substantially constant after the amount of injection rises again, and running-out of the injection is completed instantaneously.
- the amount of pre-lift of the nozzle needle which determines or decides the initial amount of injection is decided by uppermost portions of the group of parts which are moved together with the nozzle needle. Accordingly, there is a problem that dimensional management or administration of a plurality of parts in a longitudinal direction and an estimate of longitudinal deformation of the parts due to hydraulic pressure are extremely difficult.
- the nozzle element is divided into a plurality of nozzle bodies, which have conventionally been united together, and the nozzle element is provided in which the maximum-movement position is set. It is possible to set the amount of pre-lift by a location between one end to the other end of the nozzle element.
- the accumulator fuel injection apparatus it is possible to manage or administer setting of the amount of pre-lift of the nozzle needle by the spacer and the second piston.
- it is possible to facilitate operation of adjustment of the amount of pre-lift and operation of maintenance and inspection.
- an injector 100 has a casing 1 which comprises a lower element 1a, a spacer 1b, a distance piece 1c and a valve casing element 1d.
- the lower element 1a and the spacer 1b are coupled together by a first retaining ring 1e.
- the spacer 1b, the distance piece 1c and the valve casing element 1d are coupled together by a second retaining ring 1f.
- a valve sliding bore 2 and a fuel reservoir chamber 3 are defined in the valve casing element 1d.
- a nozzle needle 5 has a larger diameter portion 6 which is slidably fitted in the valve sliding bore 2 which communicates with the fuel reservoir chamber 3.
- a connecting portion 7 is formed at the larger diameter portion 6 of the nozzle needle 5.
- a smaller-diameter portion 8 and a valve portion 9 are integrally formed at a location below the connecting portion 7.
- a seat x is opened and closed by the valve portion 9 so that injection from a jetting or injection bore 4 is turned on and off.
- a first piston 11 is slidably fitted within a cylinder 14 which is defined in the lower element 1a.
- the first piston 11 is abutted against one end of a second piston 12.
- the other end of the second piston 12 is formed with a smaller-diameter portion 54, as shown in Fig. 3.
- the connecting portion 7 of the nozzle needle 5 has a forward end thereof which is slidably fitted in a cylinder 55 formed in the smaller-diameter portion 54.
- a first pressure control chamber 15 is defined within the cylinder 14, as shown in Fig. 5, to form a one-way orifice 38.
- the first pressure control chamber 15 communicates with a passage 36 through a restriction passage 35 which is defined in a valve body 29.
- a compressive coil spring 32 has one end 32a thereof which is abutted against the valve body 29. The other end 32b of the compressive coil spring 32 is abutted against the first piston 11 through a valve seat 34. If high pressure is introduced to a passage 36 from a passage 22 through an inner valve 19 and an outer valve 18, the valve body 29 is depressed or is moved downwardly so that the compressive coil spring 32 and the valve body 29 are abutted against the first piston 11 to push down the first piston 11.
- a second pressure control chamber 50 communicates with the passage 36 through a high-pressure fuel passage 56.
- an annular spring element 51 is received within the second pressure control chamber 50.
- the annular spring element 51 has one end 51a thereof which is abutted against an annular groove 52 which is formed in a bottom surface of the distance piece 1c.
- the other end 51b of the annular spring element 51 is abutted against a larger-diameter spring seat 53 which is formed at a rearward end of the nozzle needle 5.
- the connecting portion 7 is slidable vertically within the cylinder 55 which is defined in the smaller-diameter solid cylindrical portion 54 which is formed at a rearward end of the second piston 12.
- an amount of full lift and an amount of pre-lift of the nozzle needle 5 are decided.
- the amount of pre-lift H is decided by a difference between the spacer 1b and a top of the second piston 12 illustrated in Fig. 4 upon assembling.
- the three-way electromagnetic valve (control valve) 16 is arranged above the first piston 11.
- the three-way electromagnetic valve (control valve) 16 comprises valve means and magnetizing or exciting means.
- the valve means has the outer valve 18 slidably guided by a cylinder 17, and the inner valve 19 slidably guided by an internal bore 18a in the outer valve 18.
- the exciting means has a coil 20 mounted on a solenoid housing 63, a stator 60 fixedly mounted on a case 62 through the solenoid housing 63, a movable core 61 fixedly mounted on the outer valve 18 and attracted against the stator 60 upon energization, and a compressive coil spring 21 for biasing the outer valve 18 toward a side opposite to the attracting side.
- the outer valve 18 When the coil 20 is deenergized, the outer valve 18 is located at a lower position by a biasing force of the compressive coil spring 21 so that the passage 22 and the first pressure control chamber 15 communicate with each other through the passage 36. Further, when the coil 20 is energized, the outer valve 18 is moved upwardly so that the first pressure control chamber 15 and the drain passage 23 communicate with each other. In this connection, as shown in Fig. 2, fuel within a drain passage 23 can be drawn to a drain tank (not shown) through passages 43 and 44 and an outlet 27.
- the casing 1 is formed therein with a fuel supply passage 24.
- the fuel supply passage 24 has one end thereof which is connected to the fuel reservoir chamber 3 and the other end which is connected to the passage 22 in the three-way electromagnetic valve 16.
- An accumulator piping 26 accumulates high-pressure fuel which is supplied from a high-pressure supply pump (not shown).
- the accumulator piping 26 supplies the high-pressure fuel to the injectors 100 arranged respectively for cylinders, through an inlet 25.
- Signals from a cylinder judgment sensor, a cam-angle sensor, an accelerator-opening sensor and the like are inputted to a controller 28 so that the controller 28 controls the three-way electromagnetic valve 16 at predetermined fuel injection timing.
- the high-pressure fuel in the accumulator piping 26 is supplied into the injector 100 through the inlet 25.
- the fuel is supplied to the fuel reservoir chamber 3 through the fuel supply passage 24, and is supplied to the three-way electromagnetic valve 16.
- the outer valve 18 is seated by the compressive coil spring 21.
- the fuel supplied to the three-way electromagnetic valve 16 moves the inner valve 19 upwardly in the figures and flows into the passage 36.
- the fuel flowing into the passage 36 flows into the first pressure control chamber 15 through the restriction passage 35.
- the first pressure control chamber 15 is filled with the high-pressure fuel.
- the first pressure control chamber 15, the second pressure control chamber 50 and the fuel reservoir chamber 3 are high in pressure.
- the first piston 11 is abutted against a stopper 45.
- the second piston 12 is abutted against the first piston 11.
- the nozzle needle 5 is seated upon the seat x by a difference between a pressure receiving area within the second control chamber and a pressure receiving area at the fuel reservoir chamber 3 and the setting force of the annular spring element 51.
- the outer valve 18 When the three-way electromagnetic valve 16 is excited or energized, the outer valve 18 is attracted upwardly in the figures, and the fuel within the first pressure control chamber 15 escapes toward the low pressure side through the passage 36 and the drain passage 23. At this time, however, the first pressure control chamber 15 is restricted in outflow of the fuel by the restriction passage 35. Accordingly, the pressure within the first pressure control chamber 15 is not at once reduced, but is maintained to high pressure during a predetermined period of time. Thus, the first piston 11 is retained to a condition abutted against the stopper 45. At this time, the second piston 12 is located while being abutted against the first piston 11. The nozzle needle 5 rises or is moved upwardly by the amount of pre-lift indicated in Fig. 3, by a difference between pressure (low pressure) received by the pressure receiving area of the second pressure control chamber 50 and pressure (high pressure) received by the pressure receiving area at the fuel reservoir chamber 3 and the setting pressure of the annular spring element 51.
- the three-way electromagnetic valve 16 when the three-way electromagnetic valve 16 is deenergized, the high-pressure fuel is supplied to the fist pressure control chamber 15 and the second pressure control chamber 50 through the three-way electromagnetic valve 16 and the passage 36. Then, the first piston 11 receives the pressure within the first pressure control chamber 15 and is instantaneously moved downwardly in the figures. In keeping therewith, the second piston 12 and the nozzle needle 5 are moved downwardly. Thus, injection has soon come to an end.
- Fig. 6 is a time chart showing pressure variation or change of the passage 36, the second pressure control chamber 50 and the first pressure control chamber 15 due to the above-described operation.
- Fig. 7 is a time chart showing displacement of each of the first piston 11, the second piston 12 and the nozzle needle 5 in the above-mentioned operation.
- an amount of pre-lift can be adjusted by axial length of each of the distance piece 1c and the spacer 1b illustrated in Fig. 4.
- Fig. 9 by regulation or adjustment of the restriction diameter of the restriction passage 35, it is possible to control an inclination of full-lift ascending of the nozzle needle 5.
- Fig. 10 since it is possible to reduce the amount of injection during a period of ignition lag or delay time as compared with the conventional delta-type injection, it is possible to prevent dash combustion from occurring to reduce nitrogen oxides.
- the second piston 12 upon assembling, the second piston 12 is abutted against the nozzle needle 5, and the amount of pre-lift H is set by a step between the second piston 12 and the spacer 1b.
- Setting of the amount of pre-lift H of the nozzle needle 5 can be managed only by the step H between the spacer 1b and the top of the second piston 12 illustrated in Fig. 4.
- the longitudinal size of the lower element has controlled or governed the amount of pre-lift.
- dimensional management of the lower element la is dispensed with because the amount of pre-lift is decided. Accordingly, setting of the amount of pre-lift is facilitated.
- only rearrangement of the various parts illustrated in Fig. 4 into a body by the retaining ring le makes it possible to perform operation of adjustment of the amount of pre-lift and operation of inspection and maintenance. Thus, there is provided an advantage that serviceability is improved.
- the fuel injection apparatus for the diesel engine enables the boot-type injection and decides the amount of pre-lift of the nozzle needle which decides the injection rate, by the intermediate portion of the group of parts which are moved together with the nozzle needle. Accordingly, there are produced advantages that the operation of setting of the amount of pre-lift is facilitated, and operability upon maintenance and inspection is also improved. Moreover, there are produced the following advantages. That is, when the amount of pre-lift of the nozzle needle is decided, management of the longitudinal dimension of the plurality of parts which cooperate to form the injector is facilitated. Furthermore, an estimate of the longitudinal deformation of the parts due to the hydraulic pressure is facilitated.
- An accumulator fuel injection apparatus in which a nozzle element is divided into a first nozzle body having a one end side of said nozzle element and a second nozzle body having the other end side of the nozzle element.
- the accumulator fuel injection apparatus comprises a stopper for setting a maximum movement position of the first nozzle body toward the second nozzle body, a second pressure control chamber communicating with a first pressure control chamber and forming a predetermined space or interval through which the first nozzle body and the second nozzle body are spaced away from each other under a condition that the first nozzle body is arranged at the maximum movement position, and delay means for delaying reduction of pressure within the first pressure control chamber due to the fact that fluid flows into a low-pressure chamber from the first pressure control chamber upon communication of the first pressure control chamber and the low-pressure chamber with each other. It is possible to easily perform operation of setting an amount of pre-lift of the nozzle needle which decides an injection rate, and operation of assembling constitutional elements thereof.
Landscapes
- 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)
Description
- The present invention relates to an accumulator fuel injection apparatus according to the preamble of claim 1 and, more particularly, to a fuel injection apparatus for a diesel engine, which facilitates setting of an amount of pre-lift of a nozzle needle.
- As a fuel injection apparatus for a diesel engine, a generic accumulator fuel injection apparatus has been disclosed, for example, in the US-A-5 156 132 corresponding to the EP-A-393 590, which comprises common accumulator piping called a common rail for accumulating high-pressure fuel, and an injector for injecting the fuel. A nozzle needle for opening and closing an injection bore is slidably arranged within the injector. The nozzle needle defines a back-pressure chamber for retaining fuel pressure which acts on the nozzle needle. Pressure within the back-pressure chamber is so controlled as to be switched to fuel pressure on the high-pressure side and fuel pressure on the low-pressure side by a three-way electromagnetic valve. Thus, the high-pressure fuel supplied from the accumulator piping is injected from the injection bore. In order to improve engine performance, pre-lift of a nozzle needle is so set as to achieve boot-type injection which is such an injection rate that an amount of injection at initial time of injection is constant, the amount of injection is made substantially constant after the amount of injection rises again, and running-out of the injection is completed instantaneously.
- For the conventional fuel injection apparatus for the diesel engine having an arrangement of the kind referred to above, however, the amount of pre-lift of the nozzle needle which determines or decides the initial amount of injection is decided by uppermost portions of the group of parts which are moved together with the nozzle needle. Accordingly, there is a problem that dimensional management or administration of a plurality of parts in a longitudinal direction and an estimate of longitudinal deformation of the parts due to hydraulic pressure are extremely difficult.
- It is an object of the present invention to further develop an accumulator fuel injection apparatus according to the preamble of claim 1 such that the amount of pre-lift of the nozzle needle is adjustable more easily while the accumulator fuel injection apparatus is easy to assemble.
- This object is achieved by the features of claim 1.
- Advantageous further developments are set out in the dependent claims.
- Accordingly, with the accumulator fuel injection apparatus according to the invention, the nozzle element is divided into a plurality of nozzle bodies, which have conventionally been united together, and the nozzle element is provided in which the maximum-movement position is set. It is possible to set the amount of pre-lift by a location between one end to the other end of the nozzle element.
- According to an advantageous further development of the accumulator fuel injection apparatus according to the invention, it is possible to manage or administer setting of the amount of pre-lift of the nozzle needle by the spacer and the second piston. Thus, it is possible to facilitate operation of adjustment of the amount of pre-lift and operation of maintenance and inspection.
- Fig. 1 is a cross-sectional view showing a fuel injection apparatus for a diesel engine, according to an embodiment of the invention;
- Fig. 2 is a cross-sectional view showing the fuel injection apparatus for the diesel engine illustrated in Fig. 1, the cross-sectional view being cut in a cross-sectional surface different from that shown in Fig. 1;
- Fig. 3 is an enlarged cross-sectional view showing a portion B in Fig. 1;
- Fig. 4 is a cross-sectional view showing the fuel injection apparatus for the diesel engine illustrated in Fig. 1, describing operation of setting the amount of pre-lift prior to completion of assembling;
- Fig. 5 is an enlarged cross-sectional view showing a portion A illustrated in Fig. 1;
- Fig. 6 is a time chart showing pressure changing characteristic of the above-described embodiment of the invention;
- Fig. 7 is a time chart showing displacement characteristic of the above-mentioned embodiment of the invention;
- Fig. 8 is a view for description of injection characteristic of the above-described embodiment of the invention;
- Fig. 9 is a view for description of injection characteristic of the above-described embodiment of the invention; and
- Fig. 10 is a view for description of injection characteristic of the above-described embodiment of the invention.
-
- A preferred embodiment of the invention will hereunder be described with reference to the accompanying drawings.
- Referring first to Fig. 1, an
injector 100 has a casing 1 which comprises a lower element 1a, a spacer 1b, a distance piece 1c and a valve casing element 1d. The lower element 1a and the spacer 1b are coupled together by a first retaining ring 1e. The spacer 1b, the distance piece 1c and the valve casing element 1d are coupled together by a second retaining ring 1f. Avalve sliding bore 2 and afuel reservoir chamber 3 are defined in the valve casing element 1d. Anozzle needle 5 has alarger diameter portion 6 which is slidably fitted in thevalve sliding bore 2 which communicates with thefuel reservoir chamber 3. A connectingportion 7 is formed at thelarger diameter portion 6 of thenozzle needle 5. A smaller-diameter portion 8 and a valve portion 9 are integrally formed at a location below the connectingportion 7. A seat x is opened and closed by the valve portion 9 so that injection from a jetting orinjection bore 4 is turned on and off. - A first piston 11 is slidably fitted within a
cylinder 14 which is defined in the lower element 1a. The first piston 11 is abutted against one end of asecond piston 12. The other end of thesecond piston 12 is formed with a smaller-diameter portion 54, as shown in Fig. 3. The connectingportion 7 of thenozzle needle 5 has a forward end thereof which is slidably fitted in acylinder 55 formed in the smaller-diameter portion 54. - A first
pressure control chamber 15 is defined within thecylinder 14, as shown in Fig. 5, to form a one-way orifice 38. The firstpressure control chamber 15 communicates with apassage 36 through arestriction passage 35 which is defined in avalve body 29. Acompressive coil spring 32 has oneend 32a thereof which is abutted against thevalve body 29. Theother end 32b of thecompressive coil spring 32 is abutted against the first piston 11 through avalve seat 34. If high pressure is introduced to apassage 36 from apassage 22 through aninner valve 19 and anouter valve 18, thevalve body 29 is depressed or is moved downwardly so that thecompressive coil spring 32 and thevalve body 29 are abutted against the first piston 11 to push down the first piston 11. At this time, high-pressure fuel flows into the firstpressure control chamber 15 from arestriction passage 35 so that the pressure within the firstpressure control chamber 15 is soon raised to high pressure. Then, when thepassage 36 is switched to low pressure, the fuel flows out from therestriction passage 35 until pressure balance of the firstpressure control chamber 15 is broken, to maintain the first piston 11 under a depressed condition. Subsequently, when the firstpressure control chamber 15 is reduced to low pressure, pressure balance of the firstpressure control chamber 15 is broken so that the first piston 11 lifts or is moved upwardly. - A second
pressure control chamber 50 communicates with thepassage 36 through a high-pressure fuel passage 56. As shown in Fig. 3, anannular spring element 51 is received within the secondpressure control chamber 50. Theannular spring element 51 has oneend 51a thereof which is abutted against anannular groove 52 which is formed in a bottom surface of the distance piece 1c. The other end 51b of theannular spring element 51 is abutted against a larger-diameter spring seat 53 which is formed at a rearward end of thenozzle needle 5. The connectingportion 7 is slidable vertically within thecylinder 55 which is defined in the smaller-diameter solidcylindrical portion 54 which is formed at a rearward end of thesecond piston 12. Here, as shown in Fig. 3, an amount of full lift and an amount of pre-lift of thenozzle needle 5 are decided. The amount of pre-lift H is decided by a difference between the spacer 1b and a top of thesecond piston 12 illustrated in Fig. 4 upon assembling. - Referring back to Fig. 1, the three-way electromagnetic valve (control valve) 16 is arranged above the first piston 11. The three-way electromagnetic valve (control valve) 16 comprises valve means and magnetizing or exciting means. The valve means has the
outer valve 18 slidably guided by acylinder 17, and theinner valve 19 slidably guided by an internal bore 18a in theouter valve 18. The exciting means has acoil 20 mounted on asolenoid housing 63, astator 60 fixedly mounted on acase 62 through thesolenoid housing 63, amovable core 61 fixedly mounted on theouter valve 18 and attracted against thestator 60 upon energization, and acompressive coil spring 21 for biasing theouter valve 18 toward a side opposite to the attracting side. - When the
coil 20 is deenergized, theouter valve 18 is located at a lower position by a biasing force of thecompressive coil spring 21 so that thepassage 22 and the firstpressure control chamber 15 communicate with each other through thepassage 36. Further, when thecoil 20 is energized, theouter valve 18 is moved upwardly so that the firstpressure control chamber 15 and thedrain passage 23 communicate with each other. In this connection, as shown in Fig. 2, fuel within adrain passage 23 can be drawn to a drain tank (not shown) throughpassages outlet 27. - The casing 1 is formed therein with a
fuel supply passage 24. Thefuel supply passage 24 has one end thereof which is connected to thefuel reservoir chamber 3 and the other end which is connected to thepassage 22 in the three-wayelectromagnetic valve 16. Anaccumulator piping 26 accumulates high-pressure fuel which is supplied from a high-pressure supply pump (not shown). Theaccumulator piping 26 supplies the high-pressure fuel to theinjectors 100 arranged respectively for cylinders, through aninlet 25. Signals from a cylinder judgment sensor, a cam-angle sensor, an accelerator-opening sensor and the like are inputted to acontroller 28 so that thecontroller 28 controls the three-wayelectromagnetic valve 16 at predetermined fuel injection timing. - Operation will next be described.
- The high-pressure fuel in the accumulator piping 26 is supplied into the
injector 100 through theinlet 25. The fuel is supplied to thefuel reservoir chamber 3 through thefuel supply passage 24, and is supplied to the three-wayelectromagnetic valve 16. - At this time, in a case where the three-way
electromagnetic valve 16 is deenergized, theouter valve 18 is seated by thecompressive coil spring 21. The fuel supplied to the three-wayelectromagnetic valve 16 moves theinner valve 19 upwardly in the figures and flows into thepassage 36. - The fuel flowing into the
passage 36 flows into the firstpressure control chamber 15 through therestriction passage 35. Under a condition in which predetermined time elapses, the firstpressure control chamber 15 is filled with the high-pressure fuel. At this time, the firstpressure control chamber 15, the secondpressure control chamber 50 and thefuel reservoir chamber 3 are high in pressure. The first piston 11 is abutted against astopper 45. Thesecond piston 12 is abutted against the first piston 11. Thenozzle needle 5 is seated upon the seat x by a difference between a pressure receiving area within the second control chamber and a pressure receiving area at thefuel reservoir chamber 3 and the setting force of theannular spring element 51. - When the three-way
electromagnetic valve 16 is excited or energized, theouter valve 18 is attracted upwardly in the figures, and the fuel within the firstpressure control chamber 15 escapes toward the low pressure side through thepassage 36 and thedrain passage 23. At this time, however, the firstpressure control chamber 15 is restricted in outflow of the fuel by therestriction passage 35. Accordingly, the pressure within the firstpressure control chamber 15 is not at once reduced, but is maintained to high pressure during a predetermined period of time. Thus, the first piston 11 is retained to a condition abutted against thestopper 45. At this time, thesecond piston 12 is located while being abutted against the first piston 11. Thenozzle needle 5 rises or is moved upwardly by the amount of pre-lift indicated in Fig. 3, by a difference between pressure (low pressure) received by the pressure receiving area of the secondpressure control chamber 50 and pressure (high pressure) received by the pressure receiving area at thefuel reservoir chamber 3 and the setting pressure of theannular spring element 51. - Subsequently, when the pressure within the first
pressure control chamber 15 is reduced to a level so bearing as to raise the first piston 11 and thesecond piston 12, the first piston 11 and thesecond piston 12 are brought to a full-lift condition. - Subsequently, when the three-way
electromagnetic valve 16 is deenergized, the high-pressure fuel is supplied to the fistpressure control chamber 15 and the secondpressure control chamber 50 through the three-wayelectromagnetic valve 16 and thepassage 36. Then, the first piston 11 receives the pressure within the firstpressure control chamber 15 and is instantaneously moved downwardly in the figures. In keeping therewith, thesecond piston 12 and thenozzle needle 5 are moved downwardly. Thus, injection has soon come to an end. - In connection with the above, Fig. 6 is a time chart showing pressure variation or change of the
passage 36, the secondpressure control chamber 50 and the firstpressure control chamber 15 due to the above-described operation. Fig. 7 is a time chart showing displacement of each of the first piston 11, thesecond piston 12 and thenozzle needle 5 in the above-mentioned operation. As shown in Fig. 8, an amount of pre-lift can be adjusted by axial length of each of the distance piece 1c and the spacer 1b illustrated in Fig. 4. Further, as shown in Fig. 9, by regulation or adjustment of the restriction diameter of therestriction passage 35, it is possible to control an inclination of full-lift ascending of thenozzle needle 5. Moreover, as shown in Fig. 10, since it is possible to reduce the amount of injection during a period of ignition lag or delay time as compared with the conventional delta-type injection, it is possible to prevent dash combustion from occurring to reduce nitrogen oxides. - With the arrangement of the embodiment, as shown in Fig. 4, upon assembling, the
second piston 12 is abutted against thenozzle needle 5, and the amount of pre-lift H is set by a step between thesecond piston 12 and the spacer 1b. Setting of the amount of pre-lift H of thenozzle needle 5 can be managed only by the step H between the spacer 1b and the top of thesecond piston 12 illustrated in Fig. 4. Conventionally, the longitudinal size of the lower element has controlled or governed the amount of pre-lift. In the present embodiment, however, dimensional management of the lower element la is dispensed with because the amount of pre-lift is decided. Accordingly, setting of the amount of pre-lift is facilitated. Furthermore, only rearrangement of the various parts illustrated in Fig. 4 into a body by the retaining ring le makes it possible to perform operation of adjustment of the amount of pre-lift and operation of inspection and maintenance. Thus, there is provided an advantage that serviceability is improved. - Since elastic deformation of the
annular spring element 51 is relatively low as compared with that of the compressive coil spring upon assembling-of theannular spring element 51 in the aforesaid embodiment, there is also provided an advantage that the amount of pre-lift can always be maintained properly or adequately. - As described above, the fuel injection apparatus for the diesel engine, according to the invention, enables the boot-type injection and decides the amount of pre-lift of the nozzle needle which decides the injection rate, by the intermediate portion of the group of parts which are moved together with the nozzle needle. Accordingly, there are produced advantages that the operation of setting of the amount of pre-lift is facilitated, and operability upon maintenance and inspection is also improved. Moreover, there are produced the following advantages. That is, when the amount of pre-lift of the nozzle needle is decided, management of the longitudinal dimension of the plurality of parts which cooperate to form the injector is facilitated. Furthermore, an estimate of the longitudinal deformation of the parts due to the hydraulic pressure is facilitated.
- An accumulator fuel injection apparatus in which a nozzle element is divided into a first nozzle body having a one end side of said nozzle element and a second nozzle body having the other end side of the nozzle element. The accumulator fuel injection apparatus comprises a stopper for setting a maximum movement position of the first nozzle body toward the second nozzle body, a second pressure control chamber communicating with a first pressure control chamber and forming a predetermined space or interval through which the first nozzle body and the second nozzle body are spaced away from each other under a condition that the first nozzle body is arranged at the maximum movement position, and delay means for delaying reduction of pressure within the first pressure control chamber due to the fact that fluid flows into a low-pressure chamber from the first pressure control chamber upon communication of the first pressure control chamber and the low-pressure chamber with each other. It is possible to easily perform operation of setting an amount of pre-lift of the nozzle needle which decides an injection rate, and operation of assembling constitutional elements thereof.
Claims (5)
- An accumulator fuel injection apparatus comprising:a casing element (1) formed therein with a guide bore (2);a nozzle element (5, 11, 12) reciprocally guided in said guide bore (2);a first pressure control chamber (15) faced by a first end side of said nozzle element (5, 11, 12);an injection bore (4);a valve portion (9) provided at a second end side of said nozzle element (5, 11, 12) for opening and closing said injection bore (4);accumulator piping (26) in which high-pressure fluid is accumulated;a low-pressure chamber; anda control valve (16);wherein said first pressure control chamber (15) communicates with said accumulator piping (26) and with said low-pressure chamber in switching by said control valve (16), to reciprocate said nozzle element (5, 11, 12), to thereby control said injection bore (4) in opening and closing, andwherein said nozzle element (5, 11, 12) is divided into a first nozzle body (11) at said first end side, a nozzle needle (5) having said valve portion (9) at said second end side co-operating with a seat (x) of said injection bore (4) and a second nozzle body (12) disposed between said first nozzle body (11) and said nozzle needle (5), said accumulator fuel injection apparatus further comprising:a stopper (45) for setting a maximum-movement position of said first nozzle body (11) toward said second nozzle body (12);a second pressure control chamber (50) communicating in switching with said accumulator piping (26) and said low-pressure chamber in synchronism with said first pressure control chamber (15) by said control valve (16); anddelay means (29, 35) for delaying reduction of the pressure within said first pressure control chamber (15) due to the fact that fluid flows into said low-pressure chamber from said first pressure control chamber (15) upon communication of said first pressure control chamber (15) and said low-pressure chamber with each other,
said second pressure control chamber (50) faces a third end side of said second nozzle body (12) and a fourth end side of said nozzle needle (5) adjacent to said third end side of said second nozzle body (12) wherein said second nozzle body (12) is spaced away from said nozzle needle (5) by a predetermined gap on condition that said first nozzle body (11) is arranged at said maximum movement position and said nozzle needle (5) is seated on said seat (x). - An accumulator fuel injection apparatus according to claim 1,
characterized in that
said delay means (29, 35) comprises a one-way orifice (35). - An accumulator fuel injection apparatus according to claim 1 or 2,
characterized in that
said first nozzle body (11) is a first piston (11) reciprocally guided in said guide bore (2) which is formed in a lower element (la) of said casing (1); said second nozzle body (12) comprises a second piston (12) guided in said guide bore (2) which is formed in a spacer (1b) of said casing (1) and which has its fifth end side abutted against a sixth end side of said first piston (11); and wherein a biasing means (51) spaces said second piston (12) and said nozzle needle (5) apart from each other so as to form a predetermined gap between said third end side of said second piston (12) and said fourth end side of said nozzle needle (5) on condition that said first piston (11) is arranged at said maximum position. - An accumulator fuel injection apparatus according to claim 3,
characterized by
pre-lift-amount deciding means for connecting said second piston (12) and said nozzle needle (5) to each other so as to be variable in axial distance within a predetermined range, to decide an amount of pre-lift (H) of said nozzle needle (5). - An accumulator fuel injection apparatus according to claim 4,
characterized in that
said pre-lift-amount deciding means is such that a connecting portion (7) of said nozzle needle (5) is slidably fitted in a cylinder portion formed in said second piston (12).
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP214080/92 | 1992-08-11 | ||
JP21408092 | 1992-08-11 | ||
JP21408092A JPH0666219A (en) | 1992-08-11 | 1992-08-11 | Fuel injector for diesel engine |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0582993A1 EP0582993A1 (en) | 1994-02-16 |
EP0582993B1 true EP0582993B1 (en) | 2001-05-09 |
Family
ID=16649914
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19930112796 Expired - Lifetime EP0582993B1 (en) | 1992-08-11 | 1993-08-10 | Accumulator fuel injection apparatus |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0582993B1 (en) |
JP (1) | JPH0666219A (en) |
DE (1) | DE69330195T2 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4434892A1 (en) * | 1994-09-29 | 1996-04-11 | Siemens Ag | Injector |
GB9502671D0 (en) * | 1995-02-11 | 1995-03-29 | Lucas Ind Plc | Fuel system |
AT1624U1 (en) * | 1995-03-30 | 1997-08-25 | Avl Verbrennungskraft Messtech | STORAGE INJECTION SYSTEM WITH PRE-INJECTION FOR AN INTERNAL COMBUSTION ENGINE |
DE19917190A1 (en) | 1999-04-16 | 2000-10-26 | Mtu Friedrichshafen Gmbh | Fuel injector for internal combustion engine; has high pressure channel to supply fuel and nozzle needle in guide bore and has high pressure space behind guide bore to receive overflowing fuel |
DE19939939A1 (en) | 1999-08-23 | 2001-04-19 | Bosch Gmbh Robert | Injector for a common rail injection system for internal combustion engines with a compact design |
EP1795738A1 (en) * | 2005-12-12 | 2007-06-13 | C.R.F. Societa Consortile per Azioni | Fuel-injection system for an internal-combustion engine and corresponding method for controlling fuel injection |
DE102010040316A1 (en) * | 2010-09-07 | 2012-03-08 | Robert Bosch Gmbh | fuel injector |
JP6015398B2 (en) * | 2012-12-05 | 2016-10-26 | 株式会社日本自動車部品総合研究所 | Fuel injection valve |
CN115288902B (en) * | 2022-09-01 | 2023-12-08 | 哈尔滨工程大学 | Low oil return volume dual-lift variable injection pattern electronically controlled injector |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH495504A (en) * | 1968-08-28 | 1970-08-31 | Sopromi Soc Proc Modern Inject | Fuel injection valve with electromagnetic actuation |
FR2541379B1 (en) * | 1983-02-21 | 1987-06-12 | Renault | IMPROVEMENT IN ELECTROMAGNETICALLY CONTROLLED INJECTION SYSTEMS FOR A PRESSURE-TIME DIESEL ENGINE WHERE THE INJECTOR NEEDLE IS DRIVEN BY THE DISCHARGE THEN LOADING A CAPACITY |
CH669822A5 (en) * | 1986-02-12 | 1989-04-14 | Sulzer Ag | |
US5156132A (en) * | 1989-04-17 | 1992-10-20 | Nippondenso Co., Ltd. | Fuel injection device for diesel engines |
DE4027493A1 (en) * | 1989-09-19 | 1991-03-28 | Avl Verbrennungskraft Messtech | Diesel IC engine fuel injection valve - with valve needle operated via pressure slot sliding relative to cooperating hydraulic piston |
-
1992
- 1992-08-11 JP JP21408092A patent/JPH0666219A/en active Pending
-
1993
- 1993-08-10 EP EP19930112796 patent/EP0582993B1/en not_active Expired - Lifetime
- 1993-08-10 DE DE1993630195 patent/DE69330195T2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
DE69330195D1 (en) | 2001-06-13 |
EP0582993A1 (en) | 1994-02-16 |
DE69330195T2 (en) | 2001-10-18 |
JPH0666219A (en) | 1994-03-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5472142A (en) | Accumulator fuel injection apparatus | |
US5423484A (en) | Injection rate shaping control ported barrel for a fuel injection system | |
EP0823549B1 (en) | Injector | |
RU2170846C2 (en) | Internal combustion engine fuel injection device | |
US8210454B2 (en) | Fuel injector with piston restoring of a pressure intensifier piston | |
EP1053397B1 (en) | Hydraulically actuated fuel injector with seated pin actuator | |
EP1516115A1 (en) | Fuel injection system | |
JP3369015B2 (en) | Common rail fuel injection system for internal combustion engines | |
US5487508A (en) | Injection rate shaping control ported check stop for a fuel injection nozzle | |
EP1199467B1 (en) | Fuel injection system | |
EP0582993B1 (en) | Accumulator fuel injection apparatus | |
US20090114744A1 (en) | Device for the Injection of Fuel Into the Combustion Chamber of an Internal Combustion Engine | |
EP1281858A2 (en) | Fuel injection valve | |
US6213093B1 (en) | Hydraulically actuated electronic fuel injection system | |
US6935580B2 (en) | Valve assembly having multiple rate shaping capabilities and fuel injector using same | |
EP1063421A2 (en) | Fuel injector | |
EP0965751B1 (en) | Fuel injector | |
JP3846917B2 (en) | Fuel injection device | |
US6871636B2 (en) | Fuel-injection device for internal combustion engines | |
JPH10110658A (en) | Hydraulic operation fuel injector having direct controlling type needle valve | |
US20050115539A1 (en) | System for pressure-modulated shaping of the course of injection | |
JP3758727B2 (en) | Fuel injection device | |
EP0965750A2 (en) | Fuel injector | |
JP4079063B2 (en) | Fuel injection device for internal combustion engine | |
JP2887970B2 (en) | Fuel injection device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT |
|
17P | Request for examination filed |
Effective date: 19940211 |
|
17Q | First examination report despatched |
Effective date: 19960604 |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: DENSO CORPORATION |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB IT |
|
ITF | It: translation for a ep patent filed | ||
REF | Corresponds to: |
Ref document number: 69330195 Country of ref document: DE Date of ref document: 20010613 |
|
ET | Fr: translation filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20090814 Year of fee payment: 17 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20090805 Year of fee payment: 17 Ref country code: DE Payment date: 20090806 Year of fee payment: 17 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: IT Payment date: 20090813 Year of fee payment: 17 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20100810 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20110502 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20100810 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 69330195 Country of ref document: DE Effective date: 20110301 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20110301 Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20100831 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20100810 |