JP2010236393A - Gas fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quiet gas fuel injection valve by preventing the generation of standing waves at a nozzle hole. <P>SOLUTION: In the gas fuel injection valve, a single nozzle member 11 is fixed to a front end of a valve housing 2 making a gas fuel passage 6 inside and storing a vehicle body 15 therein; and a valve seat 13 facing the gas fuel passage 6, a valve hole 45 penetrating a center portion of the valve seat 13 and opened/closed by cooperation of the valve body 15 and the valve seats 13, a throttle hole 46 which connects the outlet of the valve hole 45 and has a smaller diameter throttle hole 46 than the valve hole, a nozzle hole 48 which connects to the outlet of the throttle hole 46 and has a larger diameter than the throttle hole, and a taper hole 49 connecting the throttle hole 46 and the nozzle hole 48 are formed on the nozzle member 11. The throttle hole 46 and the nozzle valve 48 are disposed so as to be eccentric each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an injection valve for gas fuel that supplies natural gas such as CNG and LPG to an internal combustion engine as a fuel, and more particularly, a gas fuel passage inside and a single valve at a front end portion of a valve housing that houses a valve body. A nozzle member, and a valve seat facing the gas fuel passage; a valve hole penetrating through a central portion of the valve seat and opened and closed by cooperation of the valve body and the valve seat; A gas that forms a throttle hole with a smaller diameter connected to the outlet of the valve hole, a nozzle hole with a larger diameter connected to the outlet of the throttle hole, and a tapered hole connecting the throttle hole and the nozzle hole. The present invention relates to an improvement of a fuel injection valve.

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

Japanese Patent Application Laid-Open No. 11-303685

  In this type of conventional gas fuel injection valve, when the valve element is opened, the high-pressure gas fuel in the gas fuel passage passes through the valve seat, and the flow rate is measured through the throttle hole. However, in the conventional system, since the change in the cross-sectional area of the flow path between the throttle hole and the nozzle hole is abrupt, when the gas fuel rapidly moves from the throttle hole to the nozzle hole, the gap between the throttle hole and the nozzle hole is reduced. The separation phenomenon of the flow occurs at the boundary of the nozzle, and this separation phenomenon becomes a sound source and the sound wave propagates to the nozzle hole, and the resonance phenomenon occurs due to the interaction with the natural frequency of the nozzle member. It will contribute.

  In particular, since the throttle hole and the nozzle hole are coaxially arranged, the separation phenomenon part, that is, the incident wave from the sound source to the nozzle hole and the reflected wave from the nozzle hole exit overlap each other in the separation phenomenon part. A standing wave was created in the hole, which promoted the resonance phenomenon.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a quiet gas fuel injection valve so as to prevent the generation of a standing wave in a nozzle hole.

  In order to achieve the above object, the present invention provides a gas fuel passage inside and a single nozzle member fixed to the front end portion of a valve housing for accommodating a valve body, and the gas fuel passage is provided in the nozzle member. A valve hole that passes through the central part of the valve seat and is opened and closed by the cooperation of the valve body and the valve seat, a throttle hole having a smaller diameter connected to the outlet of the valve hole, In a gas fuel injection valve in which a nozzle hole having a larger diameter connected to the outlet of the throttle hole and a tapered hole connecting the throttle hole and the nozzle hole are formed, the throttle hole and the nozzle hole are formed by The first feature is that they are arranged so as to be eccentric from each other.

In addition to the first feature of the present invention, when the inclination angle of the tapered hole is θ,
0 ° <θ ≧ 15 ° (1)
A second feature is that the tapered hole is formed so as to satisfy the expression (1).

Furthermore, in addition to the first feature, the present invention has the above-mentioned restriction hole in which the inner diameter is D1, the length of the restriction hole is L1, the inner diameter of the nozzle hole is D2, and the length of the nozzle hole is L2. ,
L1 / D1> 1 (2)
1 <D2 / D1 ≧ 1.2 (3)
A third feature is that the throttle hole and the nozzle hole are formed so as to satisfy the expressions (2) and (3).

  According to the first feature of the present invention, since the taper hole 47 is eccentric by a predetermined amount with respect to the nozzle hole, the taper hole 47 is formed at a portion of the inner peripheral surface of the taper hole 47 facing in the eccentric direction. When a sound wave caused by separation of the flow of gas fuel is generated from these opposed parts, a phase shift occurs between the incident waves propagating from these opposed parts to the nozzle hole. Generation of standing waves can be prevented by this interference, and noise emission from the nozzle holes can be effectively suppressed, which can contribute to the provision of a quiet gas fuel injection valve.

  According to the second feature of the present invention, by satisfying the expression (1), the tapered hole can smoothly deliver the gas fuel from the throttle hole to the nozzle hole while suppressing the separation. The generation of noise at can be more effectively prevented.

  According to the third feature of the present invention, by satisfying the expression (2), the flow of the gas fuel in the throttle hole is rectified, the fuel flow rate is stabilized, and from the throttle hole to the nozzle hole. When shifting, the flow separation phenomenon can be suppressed as much as possible, and by satisfying the above equation (3), when the gas fuel moves from the throttle hole to the nozzle hole, the flow separation phenomenon, and hence cavitation, is suppressed. It can be effectively suppressed, and the generation of noise in the nozzle hole can be more effectively prevented.

The longitudinal cross-sectional view of the injection valve for gas fuel which concerns on the Example of this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. The diagram which shows the test result of the relationship between the inclination-angle of a taper hole, and a noise sound pressure. The diagram which shows the test result of the relationship between the ratio of nozzle hole diameter to throttle hole diameter and noise sound pressure. Explanatory drawing of the noise generation mechanism in the conventional injection valve for gas fuels.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS.

  In FIG. 1, a gas fuel injection valve I according to the present invention includes a first housing portion 3 having a cylindrical shape and a front end portion caulked to a flange 3 a at the rear end of the first housing portion 3. A cylindrical second housing part 4 having a larger diameter than the part 3 and a cylindrical third housing part having a smaller diameter than the second housing part 4 are integrally connected to the rear end wall 4a of the second housing part 4. 5, and a gas fuel passage 6 is formed in the valve housing 2. The first to third housing parts 3 to 5 are all made of a magnetic material.

  The first housing part 3 has a mounting hole 8 opened at the front end thereof and a guide hole 9 opened at the rear end and having a diameter larger than that of the mounting hole 8 and coaxial with the mounting hole 8. The annular shim 10 and the disc-like nozzle member 11 are sequentially fitted and fixed by caulking inward of the front end edge of the first housing portion 3. At this time, an annular seal member 12 that is in close contact with the inner peripheral surface of the mounting hole 8 is attached to the outer periphery of the nozzle member 11. The annular shim 10 adjusts the fitting position of the nozzle member 11 by selecting the thickness thereof.

  As shown in FIG. 2, the nozzle member 11 includes a valve seat 13 facing the gas fuel passage 6, a valve hole 45 penetrating through the central portion of the valve seat 13, and an outlet of the valve hole 45. A small-diameter throttle hole 46 and a nozzle hole 48 having a diameter larger than that of the throttle hole 46 connected to the outlet of the throttle hole 46 via a tapered hole 47 are provided.

  At this time, the taper hole 47 and the nozzle hole 48 are arranged such that their axis lines A1 and A2 are decentered by a predetermined amount e. The predetermined amount e is an amount that suppresses generation of a standing wave, which will be described later, in the nozzle hole 48.

Further, the inclination angle of the tapered hole 47 is θ, the inner diameter of the throttle hole 46 is D1, the length of the throttle hole 46 is L1, the inner diameter of the nozzle hole 48 is D2, and the length of the nozzle hole 48 is L2. When
0 ° <θ ≧ 15 ° (1)
L1 / D1> 1 (2)
1 <D2 / D1 ≧ 1.2 (3)
The throttle hole 46 and the nozzle hole 48 are formed so as to satisfy the expressions (1), (2) and (3).

In FIG. 1 again, the valve body 15 is slidably received and held in the guide hole 9. The valve body 15 includes a plunger 19 formed by connecting a flange portion 16, a short shaft portion 17 ₁ , a first journal portion 18 ₁ , a long shaft portion 17 ₂ and a second journal portion 18 ₂ in a coaxial manner from the front end side. The rubber seating member 20 is bonded to the front end surface of the flange portion 16 by baking, and the seating member 20 is seated on or separated from the valve seat 13 to open and close the valve hole 45. Can do. The plunger 19 is made of a magnetic material so as to also serve as a movable core.

In the plunger 19, the minor portion 17 ₁ and the major axis portion 17 _2, first and second journal portions 18 _1, 18 ₂ are formed sufficiently smaller diameter than the first and second journal portions 18 _1, 18 ₂ Are both slidably supported in the guide hole 9.

  A coil assembly 23 is accommodated in the second housing part 4. The coil assembly 23 includes a bobbin 24, a coil 25 wound around the outer periphery of the bobbin 24, and a resin mold portion 26 for embedding the coil 25 in the bobbin 24. An annular seal member 27 is interposed between the flange 3 a of the housing part 3.

  A cylindrical fixed core 29 fitted to the inner peripheral surface of the bobbin 24 is integrally formed on the rear end wall 4a of the second housing part 4, and a seal member 28 for sealing those fitted parts is formed on the bobbin. 24 and the fixed core 29. The plunger 19 has a rear end protruding into the bobbin 24 and is opposed to the front end surface of the fixed core 29.

The plunger 19 is provided with a vertical hole 30 ending from the rear end surface in front of the flange portion 16, and a plurality of horizontal holes 31, which communicate the vertical hole 30 with the outer peripheral surface of the short shaft portion 17 ₁ . At that time, an annular spring seat 32 facing the fixed core 29 is formed in the middle of the vertical hole 30.

  On the other hand, a support hole 35 communicating with the vertical hole 30 is formed in the central portion from the fixed core 29 to the front half portion of the third housing portion 5, and in the latter half portion of the third housing portion 5, An inlet hole 36 having a diameter larger than that of the support hole 35 is provided. A pipe-like retainer 37 is inserted into the support hole 35 to support the return spring 33 that urges the valve body 15 toward the valve seat 13 with the spring seat 32, and the insertion depth is adjusted to return the return spring 33. After adjusting the set load of the spring 33, the retainer 37 is fixed to the third housing part 5 by caulking from the outer periphery of the third housing part 5. Reference numeral 38 indicates the caulking portion. A fuel filter 39 is attached to the inlet hole 36. A gas fuel distribution pipe (not shown) is connected to the rear end portion of the third housing portion 5 so that the gas fuel is distributed to the inlet holes 36. The nozzle member 11 is connected to a gas fuel conduit 50 for guiding the injected fuel from the nozzle hole 48 at a proper position of the engine.

  A resin mold portion 41 is formed from the rear end portion of the second housing portion 4 to the front half portion of the third housing portion 5 so as to cover their outer peripheral surfaces and integrally include a coupler 40 on one side. , The energization terminal 42 connected to the coil 25 is held.

  A rubber-made annular cushion member 52 facing the front end surface of the fixed core 29 is joined to the rear end surface of the valve body 15 by baking.

  Next, the operation of this embodiment will be described.

  In the demagnetized state of the coil 25, the valve body 15 is pressed forward by the urging force of the return spring 33 to seat the seating member 20 on the valve seat 13. In this state, the gas fuel sent from the gas fuel tank (not shown) to the distribution pipe flows into the inlet hole 36 of the valve housing 2 and is filtered by the fuel filter 39, and the inside of the pipe-shaped retainer 37, the valve body 15. It waits in the guide hole 9 through the vertical hole 30 and the horizontal hole 31.

  When the coil 25 is excited by energization, the magnetic flux generated by the coil 25 sequentially travels through the fixed core 29, the second housing part 4, the flange 3a, and the valve body 15, and the magnetic force of the valve body 15 resists the set load of the return spring 33. As the rubber cushion member 52 of the valve body 15 is aspirated by the fixed core 29 and abuts against the front end surface of the fixed core 29, the opening limit of the seating member 20 relative to the valve seat 13 is regulated.

  Thus, when the valve body 15 is opened, the gas fuel that has been waiting in the guide hole 9 passes through the valve seat 13, the flow rate is measured at the throttle hole 46, and then rapidly through the taper hole 47 to the nozzle hole 48. To the engine through the gas fuel conduit 50.

  At this time, it is assumed that separation of the flow of the gas fuel occurs on the inner surface of the tapered hole 47 and a sound wave is generated due to the separation. Since the taper hole 47 is eccentric by a predetermined amount e with respect to the nozzle hole 48, the portions 47 a and 47 b of the inner peripheral surface of the taper hole 47 facing in the eccentric direction have a constant distance in the axial direction of the taper hole 47. s offset, and a phase shift of a fixed distance s occurs between the incident waves a and b propagating from the facing portions 47a and 47b to the nozzle hole 48, and the occurrence of stationary waves can be prevented by their interference. , Noise emission from the nozzle hole 48 can be effectively suppressed. Therefore, the generation of noise in the nozzle hole 48 can be prevented, which can contribute to the provision of a quiet gas fuel injection valve I.

  In addition, the inclination angle θ of the tapered hole 49 is set so as to satisfy the equation (1), that is, 0 ° <θ ≧ 15 °, so that it is difficult to cause separation of the flow of gas fuel in the tapered hole 49. In addition, noise generation can be further suppressed.

  FIG. 3 shows the test results by examining the relationship between θ and the noise sound pressure measured at the outlet of the nozzle member 11. As is apparent from the test results, the sound pressure is extremely low when θ is in the range of 0 ° to 15 °, but increases rapidly when θ exceeds 15 °. That is, when θ is in the range of 0 ° to 15 °, the taper hole 49 smoothly transfers the gas fuel from the throttle hole 46 to the nozzle hole 48 with almost no peeling, and the sound pressure is extremely low. When 49 exceeds 15 °, the smooth guiding function of the taper hole 49 is lost, flow separation occurs, and noise noise pressure is increased. Further, when θ = 0 °, the measuring function of the throttle hole 46 is lost. The equation (1) is based on this test result.

  Further, since the throttle hole 46 and the nozzle hole 48 are formed so as to satisfy the formula (2), that is, L1 / D1> 1, the flow of the gas fuel in the throttle hole 46 is rectified, and the fuel flow rate is reduced. It is possible to stabilize the metering and suppress the flow separation phenomenon that occurs in the tapered hole 47 as much as possible.

  Furthermore, the throttle hole 46 and the nozzle hole 48 are formed so as to satisfy the above formula (3), that is, 1 <D2 / D1 ≧ 1.2. Therefore, cavitation can be effectively suppressed.

  FIG. 4 shows the test results by examining the relationship between D2 / D1 and the noise sound pressure measured at the outlet of the nozzle member 11. FIG. As apparent from the test results, the noise sound pressure is relatively low when D2 / D1 is in the range of 1.0 to 1.2, but increases when D2 / D1 exceeds 1.2. When D2 / D1 = 1, the metering function of the throttle hole 46 is lost. The above equation (3) is based on this test result.

  In FIG. 4, the same components as those in the previous embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention.

I: Gas fuel injection valve e: Eccentricity 2 between taper hole and nozzle hole ... Valve housing 6 ... Gas fuel passage 11 ... Nozzle member 13 ... Valve seat 14 ... Nozzle hole 15 ... Valve body 45 ... Valve hole 46 ... Restriction hole 47 ... Tapered hole 48 ... Nozzle hole

Claims (3)

A single nozzle member (11) is fixed to the front end portion of the valve housing (2) that contains the gas fuel passage (6) and accommodates the valve element (15). A valve seat (13) facing the gas fuel passage (6) and a valve hole penetrating through the central portion of the valve seat (13) and opened and closed by the cooperation of the valve body (15) and the valve seat (13) (45), a throttle hole (46) having a smaller diameter connected to the outlet of the valve hole (45), a nozzle hole (48) having a larger diameter connected to the outlet of the throttle hole (46), A gas fuel injection valve having a tapered hole (49) connecting the throttle hole (46) and the nozzle hole (48);
An injection valve for gas fuel, wherein the throttle hole (46) and the nozzle hole (48) are arranged so as to be eccentric from each other. The fuel injection valve according to claim 1,
When the inclination angle of the tapered hole (49) is θ,
0 ° <θ ≧ 15 ° (1)
The gas fuel injection valve, wherein the tapered hole (49) is formed so as to satisfy the expression (1). The fuel injection valve according to claim 1,
When the inner diameter of the throttle hole (46) is D1, the length of the throttle hole (46) is L1, the inner diameter of the nozzle hole (48) is D2, and the length of the nozzle hole (48) is L2.
L1 / D1> 1 (2)
1 <D2 / D1 ≧ 1.2 (3)
An injection valve for gas fuel, wherein the throttle hole (46) and the nozzle hole (48) are formed so as to satisfy the expressions (2) and (3).

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