EP0703363A2 - Fuel injection device - Google Patents
Fuel injection device Download PDFInfo
- Publication number
- EP0703363A2 EP0703363A2 EP95306276A EP95306276A EP0703363A2 EP 0703363 A2 EP0703363 A2 EP 0703363A2 EP 95306276 A EP95306276 A EP 95306276A EP 95306276 A EP95306276 A EP 95306276A EP 0703363 A2 EP0703363 A2 EP 0703363A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- piezoelectric device
- fuel injection
- electrode plate
- earth plate
- spring
- 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.)
- Granted
Links
- 239000000446 fuel Substances 0.000 title claims abstract description 41
- 238000002347 injection Methods 0.000 title claims abstract description 32
- 239000007924 injection Substances 0.000 title claims abstract description 32
- 238000001514 detection method Methods 0.000 claims abstract description 28
- 230000002093 peripheral effect Effects 0.000 claims description 17
- 239000000853 adhesive Substances 0.000 claims description 6
- 229920005989 resin Polymers 0.000 claims description 4
- 239000011347 resin Substances 0.000 claims description 4
- 239000011810 insulating material Substances 0.000 claims description 2
- 238000010276 construction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 125000006850 spacer group Chemical group 0.000 description 3
- 239000003365 glass fiber Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920002302 Nylon 6,6 Polymers 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- -1 polyphenylene Polymers 0.000 description 1
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
- F02M65/00—Testing fuel-injection apparatus, e.g. testing injection timing ; Cleaning of fuel-injection apparatus
- F02M65/005—Measuring or detecting injection-valve lift, e.g. to determine injection timing
-
- 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
- F02M2200/21—Fuel-injection apparatus with piezoelectric or magnetostrictive elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
- F02M2200/24—Fuel-injection apparatus with sensors
Definitions
- This invention relates to a fuel injection device capable of detecting a fuel injection time (time point for injecting a fuel) using a piezoelectric device.
- the fuel injection device includes a body, a needle valve axially slidably received in the body, and a nozzle spring for biasing the needle valve toward a valve seat formed on a lower end portion of the body.
- a nozzle port is closed during the time the needle valve sits on the valve seat and opened to allow a fuel to be injected therethrough when the needle valve lifts from the valve seat.
- This means for detecting a fuel injection time includes a piezoelectric device, and an electrode plate and an earth plate which plates are in contact with opposite end faces of the piezoelectric device, respectively.
- the piezoelectric device and the plates are disposed in an axial direction of the body.
- the nozzle spring When the needle valve lifts from the valve seat, the nozzle spring is compressed to increase its force for pressing the piezoelectric device. Consequently, an output voltage of the piezoelectric device is increased. The output voltage thus increased is served as a signal for detecting a fuel injection time.
- the detection means is received in an upper end portion (an end portion away from the valve seat and nozzle port) of a spring receiving hole formed in a body.
- a nozzle spring is received in the spring receiving hole and interposed between the detection means and the needle valve.
- an electrode plate, a piezoelectric device, and an earth plate are arranged in order toward the valve seat.
- the body has a receiving surface disposed at an upper end of the spring receiving hole.
- An insulating member is interposed between the receiving surface and the electrode plate. Owing to this arrangement, an electrically-insulated state is maintained between the electrode plate and the body.
- the earth plate is provided with a plurality of tongue pieces radially outwardly projecting from a peripheral edge area thereof. With the tongue pieces slantwise bent, the earth plate is press fitted into the spring receiving hole. The tongue pieces are resiliently contacted with an inner peripheral surface of the spring receiving hole to thereby achieve an electrical connection between the earth plate and the body.
- an electrode plate, a piezoelectric device and an earth plate are likewise arranged in order toward a valve seat as in the case with the detection means of the above-mentioned patent publication.
- An insulating member is interposed between the electrode plate and a receiving surface disposed at an upper end of a spring receiving hole.
- a sleeve portion is formed on a peripheral edge of the earth plate. This sleeve portion contacts an inner peripheral surface of the receiving hole to thereby achieve an electrical connection between the earth plate and the body.
- an object of the present invention to provide a fuel injection device which is easy to manufacture and easy to assemble and which is capable of detecting a fuel injection time with a high degree of precision.
- a fuel injection device comprising:
- a fuel injection device comprises an elongated body 10 which is to be attached to a cylinder head of an engine (not shown).
- the body 10 includes a nozzle holder 11, a spacer 12, and a nozzle 13, all arranged in order downwardly along an axis of the body.
- the body 10 further includes a nozzle nut 14 for securing the spacer 12 and nozzle 13 to the nozzle holder 11.
- the nozzle holder 11 has a spring receiving hole 15 extending axially of the body 10, a vertical hole 16a communicating with an upper end of the spring receiving hole 15 and extending axially of the body 10, and a horizontal hole 16b extending from an upper end of the vertical hole 16a in a perpendicular direction to the axis of the body 10 and opening at an outer peripheral surface of the nozzle holder 11.
- the spring receiving hole 15 is opened at a lower end face of the nozzle holder 11.
- the vertical hole 16a is smaller in diameter than the spring receiving hole 15.
- a conical receiving surface 15a is formed at a boundary area between the vertical hole 16a and the spring receiving hole 15 (i.e., at an upper end of the spring receiving hole 15).
- the nozzle 13 is provided with a valve receiving hole 17 extending axially of the body 10.
- a lower end portion of the valve receiving hole 17 is defined by a pressure receiving chamber 17a.
- a valve seat 18 and a nozzle port 19 are formed in order downwardly at a lower end portion of the nozzle 13.
- the valve receiving hole 17, the valve seat 18 and the nozzle port 19 are arranged on the axis of the body 10.
- the body 10 has a high pressure passage 20 extending through the nozzle hole 11, the spacer 12 and the nozzle 13.
- An upper end of the high pressure passage 20 is opened at an upper end face of the nozzle holder 11, and a high pressure fuel is supplied to this opening.
- a lower end of the high pressure passage 20 is in communication with the pressure receiving chamber 17a.
- a needle valve 21 is axially slidably received in the valve receiving hole 17 of the nozzle 13.
- a compressed nozzle spring 22 is received in the spring receiving hole 15. The nozzle spring 22 biases the needle valve 21 toward the valve seat 18.
- the nozzle port 19 is in a closed state.
- a high pressure fuel is supplied from a fuel injection pump (not shown) to the high pressure passage 20
- the needle valve 21 receives the fuel pressure in the pressure receiving chamber 17a and is lifted from the valve seat 18.
- the nozzle port 19 is opened to allow the high pressure fuel to be injected to a combustion chamber of the engine therethrough.
- the needle valve 21 is caused to sit on the valve seat 18 under the effect of the nozzle spring 22 and thus the fuel injection is finished.
- a detection assembly 30 (detection means) for detecting a fuel injection time is received in the upper end portion of the spring receiving hole 15.
- the detection assembly 30 is particularly clearly shown in Fig. 2.
- the nozzle spring 22 presses the detection assembly 30 upwardly through a shim 35.
- the detection assembly 30 includes an earth plate 31, a piezoelectric device 32, and an electrode plate 33, all arranged in order downwardly. This sequential order of arrangement is reverse to that of the previously described conventional device.
- a surface of the piezoelectric device 32 on the positive electrode side faces downwardly.
- the electrode plate 33 is secured to this surface by electrically-conductive adhesive agent (not shown).
- a surface of the piezoelectric device 32 on the negative electrode side faces upwardly.
- the earth plate 31 is secured to this surface by electrically-conductive adhesive agent.
- An acceptable adhesive agent includes those of silver powder compounded epoxy resins, for example.
- the earth plate 31 has a through-hole 31x formed in the center thereof.
- the earth plate 31 has a thick circular ring shape.
- a conical abutment surface 31a having an angle equal to that of the receiving surface 15a of the upper end of the spring receiving hole 15 is formed on an upper surface of the earth plate 31.
- the receiving surface 15a and the abutment surface 31a are in surface contact with each other under the effect of the nozzle spring 22.
- the piezoelectric device 32 also has a through-hole 32x formed in the center thereof.
- the piezoelectric device 32 has a circular ring shape.
- the electrode plate 33 has a disk-like shape.
- a rod portion 33a extending upwardly and axially of the body 10 is formed on the center of the electrode plate 33.
- the rod portion 33a is inserted into the through-hole 32x of the piezoelectric device 32, the through-hole 31x of the earth plate 31 and the vertical hole 16a of the nozzle holder 11.
- An upper end of the rod portion 33a is disposed at a crossing portion between the vertical hole 16a and the horizontal hole 16b.
- the detection assembly 30 is formed as a unitary part by enclosing the earth plate 31, the piezoelectric device 32 and the electrode plate 33 with an insulating member 34.
- the insulating member 34 is constituted of a glass fiber reinforced PA (polyamide) 66, a glass fiber reinforced PPS (polyphenylene sulphide), or the like.
- PA polyamide
- PPS polyphenylene sulphide
- the earth plate 31, the piezoelectric device 32 and the electrode plate 33 which were preliminarily fixed by electrically-conductive adhesive agent, are set in a metal mold and then the insulating resin is injected into the metal mold.
- the insulating member 34 includes a disk portion 34a covering a lower surface of the electrode plate 33, and a sleeve portion 34b covering outer peripheral surfaces of the earth plate 31, piezoelectric device 32 and electrode plate 33.
- the disk portion 34a of the insulating member 34 insulates the electrode plate 33 from the shim 35 and the nozzle spring 22, whereas the sleeve portion 34b insulates the piezoelectric device 32 and the electrode plate 33 from the inner peripheral surface of the spring receiving hole 15.
- a support 40 is secured to the outer peripheral surface of the nozzle holder 11 where the horizontal hole 16b is opened.
- the support 40 is provided with a connector 41 received in the horizontal hole 16b.
- a terminal 42 disposed on a distal end of the connector 41 is electrically connected to the upper end portion of the rod portion 33a of the electrode portion 33.
- the terminal 42 is constituted of a U-shaped metal plate.
- the rod portion 33a of the electrode plate 33 is held by the U-shaped terminal 42 so as to be connected to the terminal 42.
- An interface for a micro computer (not shown) for controlling a fuel injection pump is connected to the electrode plate 33 through the connector 41 and also connected to an earth terminal, not shown, secured to the nozzle holder 11.
- the detection assembly 30 thus constructed, when the needle valve 21 is lifted, the pressing force of the nozzle spring 22 applied to the piezoelectric device 32 is increased because the nozzle spring 22 is compressed. As a consequence, voltage generated in the piezoelectric device 32 is increased.
- This voltage signal is processed by the interface and input into the micro computer.
- the micro computer controls the fuel injection pump in accordance with a signal indicative of a fuel injection time.
- the earth plate 31 since the earth plate 31 is caused to contact the receiving surface 15a of the nozzle holder 11 by the nozzle spring 22, the earth plate 31 can be positively electrically connected to the nozzle holder 11.
- the pressing force of the nozzle spring 22 acts directly on the piezoelectric device 32. Consequently, accuracy of detection of the piezoelectric device 32 can be increased. It should be noted that since the Young module of the insulating member 34 is considerably larger than that of the piezoelectric device 32, the force of the nozzle spring 22 is hardly applied to the sleeve portion 34b of the insulating member 34 but it is substantially applied to the piezoelectric device 32 alone.
- the detection assembly 30 can be assembled to the nozzle holder 11 with ease.
- the receiving surface 15a of the nozzle holder 11 and the abutment surface 31a of the earth plate 31 are conical surfaces, and surface contact therebetween prevents the nozzle holder 11 from moving radially.
- the detection assembly 30 can be positively held in a predetermined position. Since it is no more required for the insulating member 34 to have the role for prohibiting the detection assembly 30 from moving radially, it becomes possible to provide a clearance A (see Fig. 2) between the outer peripheral surface of the sleeve portion 34b and the inner peripheral surface of the spring receiving hole 15. Owing to this arrangement, the insulating member 34, when rotated by the force of the nozzle spring 22, does not rub the inner peripheral surface of the spring receiving hole 15 and therefore, wear of the insulating member 34 can be prevented.
- the force of the nozzle spring can be dispersed over the entire area of the two surfaces of the piezoelectric device 32 because an electrically-conductive adhesive agent is interposed between the opposing surfaces as previously mentioned. For this reason, the piezoelectric device 32 can be prevented from cracking by great force locally applied thereto.
- an insulating material such as resin may be filled in the annular gap formed between the rod portion 33a of the electrode plate 33 and the inner peripheral surfaces of the earth plate 31 and piezoelectric device 32. Owing to this arrangement, there can be prevented a possible deterioration of insulating ability caused by dusts, etc. entered into the annular gap.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
- This invention relates to a fuel injection device capable of detecting a fuel injection time (time point for injecting a fuel) using a piezoelectric device.
- The fuel injection device includes a body, a needle valve axially slidably received in the body, and a nozzle spring for biasing the needle valve toward a valve seat formed on a lower end portion of the body. A nozzle port is closed during the time the needle valve sits on the valve seat and opened to allow a fuel to be injected therethrough when the needle valve lifts from the valve seat.
- Among fuel injection devices, there is a device of the type in which a fuel injection time is detected and such a detected signal is fed back to a control unit in order to more precisely control the injection of fuel. This means for detecting a fuel injection time includes a piezoelectric device, and an electrode plate and an earth plate which plates are in contact with opposite end faces of the piezoelectric device, respectively. The piezoelectric device and the plates are disposed in an axial direction of the body.
- When the needle valve lifts from the valve seat, the nozzle spring is compressed to increase its force for pressing the piezoelectric device. Consequently, an output voltage of the piezoelectric device is increased. The output voltage thus increased is served as a signal for detecting a fuel injection time.
- As disclosed in Japanese Patent Publication No. Sho 63-14188, the detection means is received in an upper end portion (an end portion away from the valve seat and nozzle port) of a spring receiving hole formed in a body. A nozzle spring is received in the spring receiving hole and interposed between the detection means and the needle valve. In the detection means, an electrode plate, a piezoelectric device, and an earth plate are arranged in order toward the valve seat.
- The body has a receiving surface disposed at an upper end of the spring receiving hole. An insulating member is interposed between the receiving surface and the electrode plate. Owing to this arrangement, an electrically-insulated state is maintained between the electrode plate and the body. On the other hand, it is required for the earth plate to maintain its electrically-connected state with the body. To this end, the earth plate is provided with a plurality of tongue pieces radially outwardly projecting from a peripheral edge area thereof. With the tongue pieces slantwise bent, the earth plate is press fitted into the spring receiving hole. The tongue pieces are resiliently contacted with an inner peripheral surface of the spring receiving hole to thereby achieve an electrical connection between the earth plate and the body.
- However, since it is necessary for the above-mentioned construction to press fit the earth plate into the spring receiving hole, a troublesome work is required for assembling the detection means to the body. Further, since the pressing force of the nozzle spring acting on the piezoelectric device is reduced by friction between the tongue pieces of the earth plate and the inner peripheral surface of the spring receiving hole, accuracy of detection of a fuel injection time is low.
- In another type of detection means disclosed in Japanese Laid-Open Utility Model Application No. Hei 4-47163, an electrode plate, a piezoelectric device and an earth plate are likewise arranged in order toward a valve seat as in the case with the detection means of the above-mentioned patent publication. An insulating member is interposed between the electrode plate and a receiving surface disposed at an upper end of a spring receiving hole. A sleeve portion is formed on a peripheral edge of the earth plate. This sleeve portion contacts an inner peripheral surface of the receiving hole to thereby achieve an electrical connection between the earth plate and the body. With this construction, an outer diameter of the sleeve portion must be in agreement with an inner diameter of the receiving hole with a high degree of precision. This inevitably results in increased manufacturing cost.
- It is, therefore, an object of the present invention to provide a fuel injection device which is easy to manufacture and easy to assemble and which is capable of detecting a fuel injection time with a high degree of precision.
- According to the present invention, there is provided a fuel injection device comprising:
- (a) an elongated body (10) having a spring receiving hole (15) and a valve receiving hole (17) arranged in order toward a distal end thereof and extending axially of the body, the body further having a nozzle port (19) disposed at the distal end portion and a valve seat (18) communicating with the nozzle port, the body further having a receiving surface (15a) disposed at a basal end of the spring receiving hole (15);
- (b) a needle valve (21) axially slidably received in the valve receiving hole of the body, the nozzle port being in a closed state when the needle valve sits on the valve seat, the nozzle port being opened to allow a fuel to be injected therethrough when the needle valve is lifted from the valve seat;
- (c) a nozzle spring (22) received in the spring receiving hole of the body and adapted to bias the needle valve toward the valve seat; and
- (d) detection means (30) received in the basal portion of the spring receiving hole and adapted to detect a fuel injection time by detecting an increased force of the nozzle spring, the force being increased in accordance with lifting of the needle valve, the detection means having a piezoelectric device (32), an electrode plate (33) and an earth plate (31), the electrode plate and the earth plate being in contact with axially opposite end faces of the piezoelectric device, respectively;
-
- Fig. 1 is a vertical sectional view of a fuel injection device according to one embodiment of the present invention;
- Fig. 2 is an enlarged sectional view of an important portion of the above device; and
- Fig. 3 is an enlarged plan view showing a state of connection between a rod portion of an electrode plate and a connector in the above device.
- The present invention will now be described with reference to the accompanying drawings.
- As is shown in Fig. 1, a fuel injection device comprises an
elongated body 10 which is to be attached to a cylinder head of an engine (not shown). Thebody 10 includes anozzle holder 11, aspacer 12, and anozzle 13, all arranged in order downwardly along an axis of the body. Thebody 10 further includes anozzle nut 14 for securing thespacer 12 andnozzle 13 to thenozzle holder 11. - The
nozzle holder 11 has aspring receiving hole 15 extending axially of thebody 10, avertical hole 16a communicating with an upper end of thespring receiving hole 15 and extending axially of thebody 10, and ahorizontal hole 16b extending from an upper end of thevertical hole 16a in a perpendicular direction to the axis of thebody 10 and opening at an outer peripheral surface of thenozzle holder 11. Thespring receiving hole 15 is opened at a lower end face of thenozzle holder 11. Thevertical hole 16a is smaller in diameter than thespring receiving hole 15. Aconical receiving surface 15a is formed at a boundary area between thevertical hole 16a and the spring receiving hole 15 (i.e., at an upper end of the spring receiving hole 15). - The
nozzle 13 is provided with avalve receiving hole 17 extending axially of thebody 10. A lower end portion of thevalve receiving hole 17 is defined by apressure receiving chamber 17a. Avalve seat 18 and anozzle port 19 are formed in order downwardly at a lower end portion of thenozzle 13. Thevalve receiving hole 17, thevalve seat 18 and thenozzle port 19 are arranged on the axis of thebody 10. - The
body 10 has ahigh pressure passage 20 extending through thenozzle hole 11, thespacer 12 and thenozzle 13. An upper end of thehigh pressure passage 20 is opened at an upper end face of thenozzle holder 11, and a high pressure fuel is supplied to this opening. A lower end of thehigh pressure passage 20 is in communication with thepressure receiving chamber 17a. - A
needle valve 21 is axially slidably received in thevalve receiving hole 17 of thenozzle 13. A compressednozzle spring 22 is received in thespring receiving hole 15. Thenozzle spring 22 biases theneedle valve 21 toward thevalve seat 18. - Since the above construction is known, operation thereof will be briefly described. During the time the
needle valve 21 is caused to sit on thevalve seat 18 under the effect of thenozzle spring 22, thenozzle port 19 is in a closed state. When a high pressure fuel is supplied from a fuel injection pump (not shown) to thehigh pressure passage 20, theneedle valve 21 receives the fuel pressure in thepressure receiving chamber 17a and is lifted from thevalve seat 18. As a consequence, thenozzle port 19 is opened to allow the high pressure fuel to be injected to a combustion chamber of the engine therethrough. When the supply of high pressure fuel is stopped, theneedle valve 21 is caused to sit on thevalve seat 18 under the effect of thenozzle spring 22 and thus the fuel injection is finished. - A detection assembly 30 (detection means) for detecting a fuel injection time is received in the upper end portion of the
spring receiving hole 15. Thedetection assembly 30 is particularly clearly shown in Fig. 2. Thenozzle spring 22 presses thedetection assembly 30 upwardly through ashim 35. Thedetection assembly 30 includes anearth plate 31, apiezoelectric device 32, and anelectrode plate 33, all arranged in order downwardly. This sequential order of arrangement is reverse to that of the previously described conventional device. - A surface of the
piezoelectric device 32 on the positive electrode side faces downwardly. Theelectrode plate 33 is secured to this surface by electrically-conductive adhesive agent (not shown). A surface of thepiezoelectric device 32 on the negative electrode side faces upwardly. Theearth plate 31 is secured to this surface by electrically-conductive adhesive agent. An acceptable adhesive agent includes those of silver powder compounded epoxy resins, for example. - The
earth plate 31 has a through-hole 31x formed in the center thereof. Theearth plate 31 has a thick circular ring shape. Aconical abutment surface 31a having an angle equal to that of the receivingsurface 15a of the upper end of thespring receiving hole 15 is formed on an upper surface of theearth plate 31. The receivingsurface 15a and theabutment surface 31a are in surface contact with each other under the effect of thenozzle spring 22. - The
piezoelectric device 32 also has a through-hole 32x formed in the center thereof. Thepiezoelectric device 32 has a circular ring shape. Theelectrode plate 33 has a disk-like shape. Arod portion 33a extending upwardly and axially of thebody 10 is formed on the center of theelectrode plate 33. Therod portion 33a is inserted into the through-hole 32x of thepiezoelectric device 32, the through-hole 31x of theearth plate 31 and thevertical hole 16a of thenozzle holder 11. An upper end of therod portion 33a is disposed at a crossing portion between thevertical hole 16a and thehorizontal hole 16b. Since an outer peripheral surface of therod portion 33a is separated from inner peripheral surfaces of theearth plate 31 andpiezoelectric device 32 through an annular gap, an electrically-insulated state is ensured between theelectrode plate 33 and both of theearth plate 31 and thepiezoelectric device 32. - The
detection assembly 30 is formed as a unitary part by enclosing theearth plate 31, thepiezoelectric device 32 and theelectrode plate 33 with an insulatingmember 34. The insulatingmember 34 is constituted of a glass fiber reinforced PA (polyamide) 66, a glass fiber reinforced PPS (polyphenylene sulphide), or the like. The insulatingmember 34 is favorable in strength and thermal resistance. - For molding the
detection assembly 30, theearth plate 31, thepiezoelectric device 32 and theelectrode plate 33, which were preliminarily fixed by electrically-conductive adhesive agent, are set in a metal mold and then the insulating resin is injected into the metal mold. - The insulating
member 34 includes adisk portion 34a covering a lower surface of theelectrode plate 33, and asleeve portion 34b covering outer peripheral surfaces of theearth plate 31,piezoelectric device 32 andelectrode plate 33. Thedisk portion 34a of the insulatingmember 34 insulates theelectrode plate 33 from theshim 35 and thenozzle spring 22, whereas thesleeve portion 34b insulates thepiezoelectric device 32 and theelectrode plate 33 from the inner peripheral surface of thespring receiving hole 15. - As is shown in Fig. 1, a
support 40 is secured to the outer peripheral surface of thenozzle holder 11 where thehorizontal hole 16b is opened. Thesupport 40 is provided with aconnector 41 received in thehorizontal hole 16b. A terminal 42 disposed on a distal end of theconnector 41 is electrically connected to the upper end portion of therod portion 33a of theelectrode portion 33. As is shown in Fig. 3, the terminal 42 is constituted of a U-shaped metal plate. Therod portion 33a of theelectrode plate 33 is held by theU-shaped terminal 42 so as to be connected to the terminal 42. - An interface for a micro computer (not shown) for controlling a fuel injection pump is connected to the
electrode plate 33 through theconnector 41 and also connected to an earth terminal, not shown, secured to thenozzle holder 11. - In the
detection assembly 30 thus constructed, when theneedle valve 21 is lifted, the pressing force of thenozzle spring 22 applied to thepiezoelectric device 32 is increased because thenozzle spring 22 is compressed. As a consequence, voltage generated in thepiezoelectric device 32 is increased. This voltage signal is processed by the interface and input into the micro computer. The micro computer controls the fuel injection pump in accordance with a signal indicative of a fuel injection time. - In the
detection assembly 30, since theearth plate 31 is caused to contact the receivingsurface 15a of thenozzle holder 11 by thenozzle spring 22, theearth plate 31 can be positively electrically connected to thenozzle holder 11. - Since it is not required for this embodiment, unlike the above-mentioned conventional device, to resiliently contact the
earth plate 31 to the inner peripheral surface of thespring receiving hole 15, the pressing force of thenozzle spring 22 acts directly on thepiezoelectric device 32. Consequently, accuracy of detection of thepiezoelectric device 32 can be increased. It should be noted that since the Young module of the insulatingmember 34 is considerably larger than that of thepiezoelectric device 32, the force of thenozzle spring 22 is hardly applied to thesleeve portion 34b of the insulatingmember 34 but it is substantially applied to thepiezoelectric device 32 alone. - Since it is no more required, unlike the above-mentioned conventional device, to insert, under pressure, the
earth plate 31 into thespring receiving hole 15 and since thedetection assembly 30 is molded of resin and handled as a unitary component element, thedetection assembly 30 can be assembled to thenozzle holder 11 with ease. - Further, the receiving
surface 15a of thenozzle holder 11 and theabutment surface 31a of theearth plate 31 are conical surfaces, and surface contact therebetween prevents thenozzle holder 11 from moving radially. As a consequence, thedetection assembly 30 can be positively held in a predetermined position. Since it is no more required for the insulatingmember 34 to have the role for prohibiting thedetection assembly 30 from moving radially, it becomes possible to provide a clearance A (see Fig. 2) between the outer peripheral surface of thesleeve portion 34b and the inner peripheral surface of thespring receiving hole 15. Owing to this arrangement, the insulatingmember 34, when rotated by the force of thenozzle spring 22, does not rub the inner peripheral surface of thespring receiving hole 15 and therefore, wear of the insulatingmember 34 can be prevented. - Even if the two surfaces of the
piezoelectric device 32 and the surfaces of theelectrode plate 33 andearth plate 31 placed opposite respectively to those of thepiezoelectric device 32 are not planar microscopically, the force of the nozzle spring can be dispersed over the entire area of the two surfaces of thepiezoelectric device 32 because an electrically-conductive adhesive agent is interposed between the opposing surfaces as previously mentioned. For this reason, thepiezoelectric device 32 can be prevented from cracking by great force locally applied thereto. - It should be noted that an insulating material such as resin may be filled in the annular gap formed between the
rod portion 33a of theelectrode plate 33 and the inner peripheral surfaces of theearth plate 31 andpiezoelectric device 32. Owing to this arrangement, there can be prevented a possible deterioration of insulating ability caused by dusts, etc. entered into the annular gap.
CHARACTERIZED IN THAT the electrode plate (33) is disposed between the piezoelectric device (32) and the nozzle spring (22), and the earth plate (31) is disposed between the piezoelectric device (32) and the receiving surface (15a) of the body (10), the earth plate being brought into abutment with the receiving surface (15a) of the body (10), thereby achieving an electrical contact with the body.
Claims (7)
- A fuel injection device comprising:(a) an elongated body (10) having a spring receiving hole (15) and a valve receiving hole (17) arranged in order toward a distal end thereof and extending axially of said body, said body further having a nozzle port (19) disposed at the distal end portion and a valve seat (18) communicating with said nozzle port, said body further having a receiving surface (15a) disposed at a basal end of said spring receiving hole (15);(b) a needle valve (21) axially slidably received in said valve receiving hole of said body, said nozzle port being in a closed state when said needle valve sits on said valve seat, said nozzle port being opened to allow a fuel to be injected therethrough when said needle valve is lifted from said valve seat;(c) a nozzle spring (22) received in said spring receiving hole of said body and adapted to bias said needle valve toward said valve seat; and(d) detection means (30) received in the basal portion of said spring receiving hole and adapted to detect a fuel injection time by detecting an increased force of said nozzle spring, the force being increased in accordance with lifting of said needle valve, said detection means having a piezoelectric device (32), an electrode plate (33) and an earth plate (31), said electrode plate and said earth plate being in contact with axially opposite end faces of said piezoelectric device, respectively;CHARACTERIZED IN THAT said electrode plate (33) is disposed between said piezoelectric device (32) and said nozzle spring (22), and said earth plate (31) is disposed between said piezoelectric device (32) and said receiving surface (15a) of said body (10), said earth plate being brought into abutment with said receiving surface (15a) of said body (10), thereby achieving an electrical contact with said body.
- A fuel injection device according to claim 1, in which said piezoelectric device (32) and said earth plate (31) have ring-shaped configurations, respectively, and said electrode plate (33) has a disk-like configuration, a rod portion (33a) being formed at a center of said electrode plate, said rod portion extending axially of said body (10) through said piezoelectric device and said earth plate so as to be in contact with a connector (41) supported by said body, an annular gap being formed between said rod portion and both of said earth plate and said piezoelectric device.
- A fuel injection device according to claim 2, in which an insulating material is filled in said annular gap.
- A fuel injection device according to any one of claims 1 to 3, in which said receiving surface (15a) of said body (10) is a conical surface, and said earth plate (31) has a conical abutment surface (31a) which can be brought into surface contact with said receiving surface.
- A fuel injection device according to any one of claims 1 to 4, in which said earth plate (31), piezoelectric device (32) and electrode plate (33) are attached to one another by electrically-conductive adhesive agent.
- A fuel injection device according to any one of claims 1 to 5, in which said earth plate (31), piezoelectric device (32) and electrode plate (33) are enclosed by an insulating member (34), said insulating member covering a surface of said electrode plate on the side of said nozzle spring (22) and also covering peripheral surfaces of said electrode plate and piezoelectric device.
- A fuel injection device according to claim 6, in which said insulating member (34) is a molded resin, thereby integrating said earth plate (31), piezoelectric device (32) and electrode plate (33).
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP251599/94 | 1994-09-21 | ||
JP25159994 | 1994-09-21 | ||
JP25159994A JP3274294B2 (en) | 1994-09-21 | 1994-09-21 | Fuel injection timing detection device |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0703363A2 true EP0703363A2 (en) | 1996-03-27 |
EP0703363A3 EP0703363A3 (en) | 1996-12-18 |
EP0703363B1 EP0703363B1 (en) | 1999-12-01 |
Family
ID=17225221
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19950306276 Expired - Lifetime EP0703363B1 (en) | 1994-09-21 | 1995-09-07 | Fuel injection device |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0703363B1 (en) |
JP (1) | JP3274294B2 (en) |
KR (1) | KR0168982B1 (en) |
DE (1) | DE69513604T2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004007951A2 (en) * | 2002-06-25 | 2004-01-22 | Daimlerchrysler Ag | Piezo sensor system for detecting the needle lift of a nozzle of a common rail injector |
EP1961952A1 (en) * | 2007-02-22 | 2008-08-27 | Robert Bosch Gmbh | Injector with sensor module and injection system |
EP2884093A1 (en) * | 2013-12-10 | 2015-06-17 | Robert Bosch GmbH | Sensor device for measuring force or pressure, method for producing a sensor device and fuel injector having a sensor device |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101413398B1 (en) | 2009-01-19 | 2014-06-27 | 호치키 가부시키가이샤 | Charging spray head |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6314188A (en) | 1986-07-05 | 1988-01-21 | 日立電子エンジニアリング株式会社 | Information projector |
JPH0447163A (en) | 1990-06-13 | 1992-02-17 | Mitsubishi Electric Corp | Auxiliary air control device for engine |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS56113044A (en) * | 1980-02-13 | 1981-09-05 | Nissan Motor Co Ltd | Injection timing sensor |
US4662564A (en) * | 1984-05-15 | 1987-05-05 | Diesel Kiki Co., Ltd. | Fuel injection nozzle with timing sensor |
-
1994
- 1994-09-21 JP JP25159994A patent/JP3274294B2/en not_active Expired - Fee Related
-
1995
- 1995-09-07 DE DE1995613604 patent/DE69513604T2/en not_active Expired - Fee Related
- 1995-09-07 EP EP19950306276 patent/EP0703363B1/en not_active Expired - Lifetime
- 1995-09-15 KR KR1019950030206A patent/KR0168982B1/en not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6314188A (en) | 1986-07-05 | 1988-01-21 | 日立電子エンジニアリング株式会社 | Information projector |
JPH0447163A (en) | 1990-06-13 | 1992-02-17 | Mitsubishi Electric Corp | Auxiliary air control device for engine |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004007951A2 (en) * | 2002-06-25 | 2004-01-22 | Daimlerchrysler Ag | Piezo sensor system for detecting the needle lift of a nozzle of a common rail injector |
WO2004007951A3 (en) * | 2002-06-25 | 2004-03-04 | Daimler Chrysler Ag | Piezo sensor system for detecting the needle lift of a nozzle of a common rail injector |
EP1961952A1 (en) * | 2007-02-22 | 2008-08-27 | Robert Bosch Gmbh | Injector with sensor module and injection system |
EP2884093A1 (en) * | 2013-12-10 | 2015-06-17 | Robert Bosch GmbH | Sensor device for measuring force or pressure, method for producing a sensor device and fuel injector having a sensor device |
Also Published As
Publication number | Publication date |
---|---|
JP3274294B2 (en) | 2002-04-15 |
EP0703363B1 (en) | 1999-12-01 |
KR0168982B1 (en) | 1999-01-15 |
EP0703363A3 (en) | 1996-12-18 |
DE69513604D1 (en) | 2000-01-05 |
DE69513604T2 (en) | 2000-07-13 |
JPH0893602A (en) | 1996-04-09 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1167747B1 (en) | Improved structure of fuel injector using piezoelectric actuator | |
US5040731A (en) | Electromagnetic fuel injection and method of producing the same | |
EP0446214A1 (en) | Electromagnetic fuel injector with diaphragm spring. | |
EP0703363B1 (en) | Fuel injection device | |
US4471914A (en) | Electromagnetically actuatable valve | |
US4340181A (en) | Fuel injection nozzle for internal combustion engines | |
RU2161724C2 (en) | Fuel injector for internal-combustion engine | |
JPH04279756A (en) | Contacting strip for electrically interconnecting touchably plurality of units being energized electrically in internal combustion engine | |
US4662564A (en) | Fuel injection nozzle with timing sensor | |
US20030183201A1 (en) | Fuel injection valve | |
US4501407A (en) | Solenoid actuated fluid control valve | |
US7032833B2 (en) | Fuel injection valve | |
US20080035762A1 (en) | Fuel Injector | |
CA2050209A1 (en) | Fuel injector for an internal combustion engine | |
US6676045B2 (en) | Fuel injection valve comprising an adjusting bush | |
US8770498B2 (en) | Fuel injector | |
US6435429B1 (en) | Fuel injection valve | |
KR102228300B1 (en) | Fuel injector | |
US6685113B1 (en) | Actuator | |
DE3130238A1 (en) | Pressure sensor for internal-combustion engines | |
US6915960B2 (en) | Fuel-injection and a method for setting the same | |
US6938880B2 (en) | Injection valve comprising an optimized surface geometry between a nozzle body and a retaining nut | |
US6553969B1 (en) | Device for assembling and dismantling a fuel injection valve | |
US20030048045A1 (en) | Piezo actuator | |
JP2639102B2 (en) | Fuel injection valve |
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: A2 Designated state(s): DE GB |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): DE GB |
|
17P | Request for examination filed |
Effective date: 19970121 |
|
17Q | First examination report despatched |
Effective date: 19980504 |
|
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 GB |
|
REF | Corresponds to: |
Ref document number: 69513604 Country of ref document: DE Date of ref document: 20000105 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20000828 Year of fee payment: 6 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20000906 Year of fee payment: 6 |
|
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 | ||
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: 20010907 |
|
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: 20020501 |