JP2014070571A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve capable of increasing a fuel injection amount by enabling the enlargement of a fuel flow path around a valve element without increasing a stroke for opening the valve element.SOLUTION: A fuel injection valve includes: a valve assembly 10 having a valve element 13 for opening/closing a nozzle hole 9 in cooperation with a valve seat 7, a connection rod 14 connected to a rear end of the valve element 13, and a movable core 12 connected to a rear end of the connection rod 14 and opposed to a front end of a fixed core 5; and a coil 22 arranged so as to encircle the fixed core 5 for attracting the movable core 12 to the fixed core 5 with a current carried thereto to open the valve element 13. Between the connection rod 14 and a valve housing 3, a fuel chamber 55 is provided in communication with a fuel supply part, and between the valve element 13 and the valve housing 3, an outside fuel passage 57 is provided for communicating the fuel chamber 55 with the nozzle hole 9 when the valve element 13 is opened. In the valve element 13, an inside fuel passage 56 is provided in parallel to the outside fuel passage 57 for communicating the fuel chamber 55 with the nozzle hole 9 when the valve element 13 is opened.

Description

  The present invention relates to a nozzle member having a nozzle hole and a valve seat, a cylindrical valve housing connected to the rear end of the nozzle member, a fixed core connected to the rear end of the valve housing, and the valve A valve body accommodated in the housing and opening and closing the nozzle hole in cooperation with the valve seat, a linkage connected to the rear end of the valve body, and a fixed end connected to the rear end of the linkage A valve assembly comprising a movable core facing the front end of the core, a return spring that is compressed between the fixed core and the valve assembly and biases the valve body toward the valve closing side, and surrounds the fixed core And a coil for opening the valve element by attracting the movable core to the fixed core by the generated magnetic force when energized, and a fuel supply section between the linkage and the valve housing. A fuel chamber in communication with the valve body and the valve housing. Between grayed, upon opening of the valve body, an improvement of a fuel injection valve provided with outer fuel passage communicating the fuel chamber to the nozzle hole.

  Such a fuel injection valve is already known as disclosed in Patent Document 1 below.

JP 2006-77777 A

  In such a fuel injection valve, when the valve element is opened, the fuel in the outer fuel chamber on the outer periphery of the valve element is injected from the nozzle hole through a flow path formed between the valve element and the valve seat. By the way, with the increase in engine output, there is a demand for an increase in fuel injection amount. To meet this demand, the valve opening stroke of the valve body is set large, and the fuel flow path between the valve body and the valve seat is widened. Although it is conceivable, doing so is not preferable because it causes not only an increase in the capacity of the coil, and an increase in the size of the fuel injection valve, but also an increase in the power consumption of the coil.

  The present invention has been made in view of such circumstances, and can increase the fuel injection amount by enabling expansion of the fuel flow path around the valve body without increasing the valve opening stroke. An object of the present invention is to provide the fuel injection valve.

  To achieve the above object, the present invention provides a nozzle member having a nozzle hole and a valve seat, a cylindrical valve housing connected to the rear end of the nozzle member, and a rear end of the valve housing. A fixed core, a valve body housed in the valve housing and opening / closing the nozzle hole in cooperation with the valve seat, a linkage connected to a rear end of the valve body, and a back of the linkage A valve assembly comprising a movable core connected to the end and facing the front end of the fixed core, and a return spring that is contracted between the fixed core and the valve assembly and biases the valve body toward the valve closing side And a coil that is disposed so as to surround the fixed core and opens the valve body by attracting the movable core to the fixed core by a generated magnetic force when energized. A fuel chamber that communicates with the fuel supply section is provided between the valve housings. In a fuel injection valve provided with an outer fuel passage that communicates the fuel chamber with the nozzle hole between the valve body and the valve housing when the valve body is opened, the valve body is opened in the valve body. The first feature is that an inner fuel passage that communicates the fuel chamber with the nozzle hole is provided in parallel with the outer fuel passage.

  According to the present invention, in addition to the first feature, the outer peripheral surface of the front end of the linkage is fitted and connected to the inner peripheral surface of the annular valve body, and the inner peripheral surface of the valve body and the communication surface are connected. A second feature is that at least one of the outer peripheral surfaces of the rod is provided with a notch communicating between the fuel chamber and the inner fuel passage.

  According to the first feature of the present invention, the fuel chamber and the nozzle hole on the outer periphery of the connection communicate with each other via the mutually parallel inner and outer fuel passages provided inside and outside the valve body. Thus, the fuel injection amount from the nozzle hole can be easily increased without increasing the valve opening stroke of the valve body, and the engine output can be increased. In addition, since there is no need to increase the valve opening stroke, it is possible to avoid an increase in the size of the coil and thus the fuel injection valve, and it is possible to suppress an increase in power consumption of the coil.

  According to the second feature of the present invention, the fuel chamber and the inner fuel passage are communicated with each other by a simple structure in which a notch is provided on at least one of the inner peripheral surface and the outer peripheral surface of the valve body and the connecting portion. Thus, the fuel can be smoothly moved from the fuel chamber to the inner fuel passage.

1 is a longitudinal sectional view of a gas fuel injection valve according to a first embodiment of the present invention. FIG. 2 is an enlarged view of part 2 in FIG. 1 (however, the valve is open). FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 3 is an exploded perspective view of the valve assembly in FIG. 2. FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment of the present invention. FIG. 6 is a view corresponding to FIG. 5 showing a third embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the injection valve of the present invention, the nozzle member side is referred to as the front, and the fuel inlet cylinder side is referred to as the rear.

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS. 1 and 2, the gas fuel injection valve I has a front end portion attached to a mounting hole Ea provided in the pipe wall of the intake pipe E of the engine, and gas fuel is introduced into the intake pipe E during the intake stroke of the engine. Spray. A valve body 1 of the injection valve I includes a cap-shaped nozzle member 2 and a hollow cylindrical valve made of a magnetic material that is joined by welding or the like by fitting the front end portion to the inner peripheral surface of the nozzle member 2. A housing 3, a fixed core 5 integrally connected to the rear end of the valve housing 3 via a nonmagnetic cylinder 4, and a hollow cylindrical fuel integrally connected to the rear end of the fixed core 5 It consists of an inlet tube 6. The fixed core 5 has a front end portion that has a front end surface as an attraction surface 5 a and is inserted into the nonmagnetic cylindrical body 4.

  The nozzle member 2 is provided with a flat valve seat 7 and a plurality of nozzle holes 9 arranged on a predetermined circumference C (see FIG. 3) in the valve seat 7.

  A central portion of the fixed core 5 is provided with a rear spring accommodating hole 19 and a retainer press-fitting hole 18 having a larger diameter connected to the rear end of the rear spring accommodating hole 19. A pipe-like return spring retainer 36 having a hollow portion 36a on the surface is press-fitted and fixed. The spring retainer 36 is provided with a single slit 37, whereby the spring retainer 36 can be elastically reduced in diameter. Considering this, the inner diameter of the retainer press-fitting hole 18 is set larger than the inner diameter in a free state. A rear spring seat 35 is constituted by the front end face of the spring retainer 36.

  A hollow portion 6a of the fuel inlet cylinder 6 having a larger diameter is connected to the rear end of the retainer press-fitting hole 18, and a fuel filter 38 is attached to the inlet of the fuel inlet cylinder 6.

  As shown in FIGS. 2 to 4, the inner peripheral surface of the valve housing 3 is a sliding guide surface 3a, and the valve assembly 10 is fitted on the sliding guide surface 3a. The valve assembly 10 is slidably fitted to the sliding guide surface 3 a and has a cylindrical movable core 12 whose rear end face is opposed to the suction surface 5 a at the front end of the fixed core 5, and the valve seat 7. It is comprised by the valve body 13 which act | operates and opens and closes the said nozzle holes 9, 9, ..., and the said movable core 12 and the valve body 13 are connected between the small diameter continuous rods 14 from those. A predetermined gap corresponding to the valve opening stroke of the valve body 13 is set between the opposed surfaces of the fixed core 5 and the movable core 12 when the valve body 13 is seated on the valve seat 7.

  The movable core 12 has a front spring accommodating hole 30 aligned coaxially with the rear spring accommodating hole 19 of the fixed core 5 at the center thereof, and a connecting cylinder portion 12a at the front end thereof.

  The valve body 13 generally has a hollow cylindrical shape, and includes an annular valve portion 13a facing the valve seat 7 and a connecting cylinder portion 13b integrally connected to the rear end of the valve portion 13a. The part 13a opens and closes the nozzle holes 9, 9 ... by being separated from and seated on the valve seat 7.

  Further, the connecting cylinder portion 13b has a flange-like journal portion 13b1 on the outer periphery thereof that is slidably fitted to the sliding guide surface 3a. The connecting cylinder portion 13b is provided with a plurality of first notches 50, 50,... That open to the inner peripheral surface, the outer peripheral surface, and the rear end surface.

  The connecting rod 14 is composed of a pair of front and rear cylindrical connecting ends 14a and 14a and a connecting flange 14b integrally connecting the connecting ends 14a and 14a. There is no. One of the connecting end portions 14a is fitted to the inner peripheral surface of the connecting cylindrical portion 12a of the movable core 12 and connected by welding or the like, and the other connecting cylindrical portion 14a is connected to the inner periphery of the connecting cylindrical portion 13b of the valve body 13. Fitting to the surface and joining by welding or the like. In this way, the movable core 12, the linkage 14, and the valve body 13 are integrally coupled.

  Each connecting end 14 a of the linkage 14 has a circular recess 51 that opens to its end surface, a plurality of second notches 52 that open the recess 51 to the outer peripheral surface, and protrudes from the bottom surface of the recess 51. And a conical guide protrusion 53 is provided. Further, on the outer periphery of the flange portion 14b, a plurality of longitudinal grooves 54, 54... Communicating between the second notches 52, 52 of the front and rear connection end portions 14a, 14a are provided. A part of the rear end face of the rear connecting end portion 14 a fitted to the connecting cylindrical portion 12 a of the movable core 12 constitutes an annular front spring seat 34 that faces the front spring accommodating hole 30 of the movable core 12. Further, the front connecting end portion 14a and the connecting cylinder portion 13b of the valve body 13 are fitted so that the phases of the first and second notches 50 and 52 coincide with each other.

  Between the connecting rod 14 and the inner peripheral surface of the valve housing 3 facing the outer peripheral surface thereof, the vertical grooves 54, 54... Of the connecting rod 14 and the first notches 50, 50. The first notch 50 has a bottom surface 50a facing the fuel chamber 55 in the axial direction.

  The hollow portion of the valve portion 13a is an inner fuel passage 56, and communicates with the nozzle holes 9, 9 ... when the valve portion 13a is separated from the valve seat 7. The inner fuel passage 56 communicates with the recess 51 and the second notches 52, 52... Of the front connection end 14a.

  The valve housing 3 is provided with an enlarged diameter portion 3b facing the front portion of the valve body 13 from the journal portion 13b1 between the inner circumference surface of the enlarged diameter portion 3b and the valve body 13. Is formed with an outer fuel passage 57 communicating with the first notches 50, 50.

  In FIG. 1 again, a return spring 33 disposed in the rear and front spring accommodating holes 19 and 30 is contracted between the front spring seat 34 and the rear spring seat 35 with a predetermined set load. The load urges the valve body 13 in the valve closing direction, that is, in the seating direction on the valve seat 7. The set load is adjusted by the press-fitting depth of the spring retainer 36 into the retainer press-fitting hole 18.

  A coil assembly 20 is disposed from a region where the movable core 12 of the valve housing 3 is fitted to the fixed core 5 and surrounding them. The coil assembly 20 includes a valve housing 3, a bobbin 21 fitted to the outer periphery of the nonmagnetic cylindrical body 4 and the fixed core 5, and a coil 22 wound around the outer periphery of the bobbin 21. A magnetic coil housing 23 is disposed on the outer periphery of the solid 20 to cover it.

  The fixed core 5 is integrally formed with a yoke flange 24 that protrudes from the outer peripheral surface and supports the rear end surface of the bobbin 21, and the rear end portion of the coil housing 23 is fitted to the outer peripheral surface of the yoke flange 24. Further, an annular end wall 23a abutting against the front end surface of the bobbin 21 and a forward projection from the inner peripheral end of the annular end wall 23a are fitted and fixed to the outer peripheral surface of the valve housing 3 at the front end portion of the coil housing 23. The cylindrical portion 23b is integrally formed. Thus, the coil assembly 20 and the coil housing 23 are attached to the valve body 1. A resin mold layer 26 that continuously covers them is formed on the outer peripheral surfaces of the coil housing 23 and the fuel inlet cylinder 6, and a coupler 28 that projects to one side is integrally formed on the resin mold layer 26. The molded coupler 28 holds a current-carrying terminal 27 connected to the coil 22.

  A pair of front and rear flanges 41 and 42 that define an annular front seal groove 40 are formed on the outer periphery of the nozzle member 2, and the nozzle member 2 is attached to a mounting hole for an intake pipe E of the engine in the front seal groove 40. When inserted into Ea, a seal member 43 that is in close contact with the inner peripheral surface thereof is mounted.

  An annular rear seal groove 45 is defined on the outer periphery of the rear end portion of the fuel inlet tube 6, and the inner periphery of the fuel distribution pipe D fitted to the rear end portion of the fuel inlet tube 6 is formed in the rear seal groove 45. A seal member 47 that is in close contact with the surface is attached.

  Next, the operation of the first embodiment will be described.

  In the demagnetized state of the coil 22, the valve assembly 10 is pressed forward by the set load of the return spring 33 as shown in FIG. 1, and the valve body 13 is seated on the valve seat 7.

  When the coil 22 is excited by energization, the magnetic flux generated by the coil 22 sequentially travels through the coil housing 23, the valve housing 3, the movable core 12, the fixed core 5, and the coil housing 23, and the magnetic force generated between the fixed core 5 and the movable core 12 As shown in FIG. 2, the valve assembly 10 is attracted to the suction surface 5 a of the fixed core 5 against the set load of the return spring 33, the valve body 13 is separated from the valve seat 7, and the nozzle holes 9, 9 …open.

  When the nozzle holes 9, 9... Are opened, the gas fuel sent from the gas fuel tank (not shown) to the fuel distribution pipe D flows into the fuel inlet cylinder 6 and is filtered by the fuel filter 38, and the hollow portion 36a of the spring retainer 36 is obtained. After passing through the rear spring accommodating hole 19 of the fixed core 5 and the front spring accommodating hole 30 of the movable core 12, it flows into the concave portion 51 at the rear part of the linkage 14. The gas fuel that has flowed into the rear recess 51 is deflected in the radial direction by the conical guide protrusion 53 protruding from the bottom surface of the recess 51, so that a plurality of second notches 52, 52. Therefore, the gas fuel does not stagnate at the bottom of the recess 51. The gas fuel moved from the recess 51 to the fuel chamber 55 in the valve housing 3 flows forward, and a part of the fuel hits the bottom surfaces 50a of the plurality of first notches 50, 50. The fuel flows into the inner and outer fuel passages 56 and 57 substantially evenly, and the other fuel flows along the longitudinal grooves 54, 54... Of the linkage 14 and passes through the second notches 52, 52. Then, it flows into the inner fuel passage 56 inside the valve portion 13a. At that time, the gas fuel flowing down the bottom surfaces of the longitudinal grooves 54, 54... Can be guided into the lower conical guide protrusion 53 and smoothly flow into the recess 51. In this way, the gas fuel that has been diverted from the fuel chamber 55 into the inner and outer fuel passages 56, 57 is injected into the intake pipe E of the engine through the plurality of nozzle holes 9, 9.

  As described above, the fuel chamber 55 on the outer periphery of the linkage 14 and the nozzle holes 9, 9... , The fuel flow path around the valve body 13 is enlarged, and the fuel injection amount from the nozzle holes 9, 9... Can be easily increased without particularly increasing the valve opening stroke of the valve body 13. It can be increased to meet the higher engine output. Further, since it is not necessary to increase the valve opening stroke of the valve body 13, it is possible to avoid an increase in the size of the coil 22, and hence the injection valve I, and to suppress an increase in power consumption of the coil 22.

  In particular, the inner and outer fuel passages 56 and 57 are provided at the rear end portion of the valve body 13 and open to the inner peripheral surface, the outer peripheral surface and the rear end surface thereof, and the inner peripheral surface of the valve body 13. The valve body 13 and the connecting rod 14 are fitted to each other through the second notch 52 provided at the connecting end portion 14a of the front portion of the connecting rod 14 fitted and connected to the fuel chamber 55. The fuel can be smoothly diverted from the fuel chamber 55 to the inner and outer fuel passages 56 and 57 without being interrupted by the joint. In addition, the individual manufacture of the valve body 13 and the linkage 14 can be facilitated, and the first and second notches 50 and 52 can be formed at the time of manufacture, so that productivity can be improved.

  The first notch 50 has a bottom surface 50a for diverting the fuel received from the fuel chamber 55 to the inner and outer fuel passages 56 and 57, so that the fuel flowing down from the fuel chamber 55 to the first notch The bottom surface of the notch 50 allows a substantially uniform flow to the inner and outer fuel passages, thereby equalizing the fuel flow rate from the inner and outer fuel passages 56 and 57 to the nozzle holes 9 and increasing the fuel injection amount. Can be made easier.

  Next, a second embodiment of the present invention shown in FIG. 5 will be described.

  In the second embodiment, the connecting cylinder portion 13b of the valve body 13 has a cylindrical shape that is welded by fitting the inner peripheral surface to the outer peripheral surface of the front connecting end portion 14a without any breaks. A plurality of notches 58, 58... Communicating the fuel chamber 55 with the outer fuel passage 57 are formed on the outer peripheral surface of the cylinder portion 13b, and the inner fuel passage 56 in the valve portion 13a is connected to the outer periphery of the front connecting end portion 14a. Are communicated with the fuel chamber 55 through the second notches 52, 52. Since other configurations are the same as those of the first embodiment, portions corresponding to those of the first embodiment in FIG. 5 are denoted by the same reference numerals, and redundant description is omitted.

  According to the second embodiment, the communication structure between the fuel chamber 55 and the inner fuel passage 56 is simplified, and the connecting cylinder portion 13b of the valve body 13 has a continuous inner peripheral surface and is not connected to the front connecting end portion 14a. High rigidity can be secured by fitting and fixing to the outer peripheral surface.

  Finally, a third embodiment of the present invention shown in FIG. 6 will be described.

  In the third embodiment, the connection end portion 14a at the front portion of the linkage 14 is not provided with a notch, and the fuel chamber 55 is disposed on the inner peripheral surface of the connection cylinder portion 13b of the valve body 13 fitted therein. Notches 59, 59... Communicating with the passage 56 are formed. Since the other configuration is the same as that of the second embodiment, portions corresponding to those of the second embodiment are denoted by the same reference numerals in FIG.

  Also according to the third embodiment, the communication structure between the fuel chamber 55 and the inner fuel passage 56 is simplified, and the connecting cylinder portion 13b of the valve body 13 has no circumferential cut, so that high rigidity can be obtained. it can.

  The present invention is not limited to the embodiments described above, and various design changes can be made without departing from the scope of the invention. For example, the present invention can be applied to an injection valve for liquid fuel such as gasoline.

I ... Fuel injection valve (Injection valve for gas fuel)
2 ... Nozzle member 3 ... Valve housing 5 ... Fixed core 7 ... Valve seat 9 ... Nozzle hole 10 ... Valve assembly 12- ... movable core 13 ... valve element 14 ... linkage 22 ... coil 33 ... return spring 52 ... notch on the outer peripheral surface of the front end of the linkage (second Notch)
55... Fuel chamber 56... Inner fuel passage 57... Outer fuel passage 59.

Claims (2)

A nozzle member (2) having a nozzle hole (9) and a valve seat (7), a cylindrical valve housing (3) connected to the rear end of the nozzle member (2), and the valve housing (3) A fixed core (5) connected to the rear end of the valve body, and a valve body (13) accommodated in the valve housing (3) and opening and closing the nozzle hole (9) in cooperation with the valve seat (7). ), The linkage (14) connected to the rear end of the valve body (13), and the movable core (14) connected to the rear end of the linkage (14) and facing the front end of the fixed core (5). 12) and a return spring (33) which is contracted between the fixed core (5) and the valve assembly (10) and biases the valve body (13) toward the valve closing side. ) And the fixed core (5) so as to surround the movable core (12) by the generated magnetic force when energized. And a coil (22) for opening the valve element (13) by suction, and a fuel chamber communicating with the fuel supply section between the connection (14) and the valve housing (3). (55) is provided, and the fuel chamber (55) communicates with the nozzle hole (9) between the valve body (13) and the valve housing (3) when the valve body (13) is opened. In the fuel injection valve provided with the outer fuel passage (57),
An inner fuel passage that communicates the fuel chamber (55) with the nozzle hole (9) in parallel with the outer fuel passage (57) when the valve body (13) is opened in the valve body (13). (56) A fuel injection valve characterized by comprising: The fuel injection valve according to claim 1, wherein
The outer peripheral surface of the front end of the linkage (14) is fitted and connected to the inner peripheral surface of the annular valve body (13), and the inner peripheral surface of the valve body (13) and the linkage (14). A fuel injection valve characterized in that notches (52, 59) communicating between the fuel chamber (55) and the inner fuel passage (56) are provided in at least one of the outer peripheral surfaces of the fuel injection valve.

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