JP2012167650A - Injection valve for gaseous fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silent injection valve for gaseous fuel, suppressing leakage of noise to the outside of a nozzle member, while allowing the formation of a spray form of the gaseous fuel satisfactorily mixing with an intake air flow in an intake pipe.SOLUTION: The single nozzle member 11 is fixed to the front end of a valve housing 2, and in the single nozzle member 11, a valve seat 13, a valve hole 45 penetrating through the center of the valve seat 13, a throttle hole 46 connected to an outlet of the valve hole 45 and smaller in diameter than that, and a nozzle hole 48 connected to the outlet of the throttle hole 46 and larger in diameter than that are formed. Thereby, in the injection valve for gaseous fuel, the gaseous fuel is directly injected into the intake pipe E of an engine from the nozzle member 11. In the injection valve for gaseous fuel, an end wall 53, facing a front opening face of the nozzle hole 48, and a plurality of gaseous fuel injection holes 55, penetrating through the end wall 53 and arranged around a central axis Y of the nozzle member 11, are provided in a nozzle cap 50 mounted on a front end of the nozzle member 11.

Description

  The present invention relates to a gas fuel injection valve that supplies natural gas such as CNG or LPG to an engine as a fuel, and in particular, a nozzle member is fixed to a front end portion of a valve housing that has a gas fuel passage inside and accommodates a valve body. A valve seat facing the gas fuel passage, a valve hole penetrating through the central portion of the valve seat and opened and closed by the cooperation of the valve body and the valve seat; An injection for gas fuel that forms a throttle hole with a smaller diameter connected to the outlet and a nozzle hole with a larger diameter connected to the outlet of the throttle hole, and directly injects gas fuel into the intake pipe of the engine from the nozzle member It relates to the improvement of the 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

  Conventionally, in this type of 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 after the flow rate is measured by the throttle hole, it moves to the nozzle hole. In the conventional system, the change in the cross-sectional area of the flow path between the throttle hole and the nozzle hole is abrupt. Therefore, when the gas fuel rapidly moves from the throttle hole to the nozzle hole, the boundary between the throttle hole and the nozzle hole is A flow separation phenomenon occurs, and this separation phenomenon serves as a sound source to generate noise in the nozzle hole. If this leaks to the outside, an abnormal sound that is audible to the user is generated.

  Therefore, in the gas fuel injection valve disclosed in Patent Document 1, the front opening end of the nozzle hole is closed with a plug, and a plurality of radial gas fuel injection holes connected to the nozzle hole are formed in the peripheral wall of the nozzle member. In addition, the noise generated in the nozzle hole is blocked by a plug to prevent leakage of the noise to the outside and the injection of gas fuel. However, since the injection direction of the gas fuel from each fuel injection hole is a radial direction and the injected fuel collides with the inner wall of the intake pipe, the spray of the gas fuel that can be well mixed with the intake air flow in the intake pipe Forming is difficult.

  The present invention has been made in view of such circumstances, and suppresses leakage of noise to the outside of the nozzle member while enabling formation of a spray form of gas fuel that can be well mixed with the intake air flow in the intake pipe. An object of the present invention is to provide a quiet injection valve for gas fuel.

  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 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, A gas fuel injection valve is formed at the front end of the nozzle member, in which a nozzle hole having a diameter larger than that of the throttle hole is formed, and gas fuel is directly injected into the engine intake pipe from the nozzle member. The nozzle cap is provided with an end wall facing the front opening surface of the nozzle hole, and a plurality of gas fuel injection holes that pass through the end wall and open to the nozzle hole around the central axis of the nozzle member. This is the first feature.

  According to the present invention, in addition to the first feature, each of the gas fuel injection holes is formed so as to incline in a direction away from the central axis of the nozzle member as the central axis thereof goes in front of the nozzle cap. Is the second feature.

  Furthermore, in addition to the first or second feature, the present invention has a third feature that the number of the gas fuel injection holes is 2 to 6.

  Furthermore, the present invention is characterized in that, in addition to the first feature, the end wall is formed in a conical shape having a vertex on the front side thereof.

  Furthermore, in addition to the first feature, the present invention provides an outer peripheral surface of the nozzle member by a flange formed on the nozzle cap and a ring body formed on the outer periphery of the nozzle member behind the nozzle cap. A seal groove that faces the inner peripheral surface of the mounting hole when the nozzle member is fitted into the mounting hole of the intake pipe of the engine is attached to the sealing groove. It is characterized by. The seal member corresponds to an O-ring 59 in an embodiment of the present invention described later.

  According to the first aspect of the present invention, the nozzle cap attached to the front end of the nozzle member has an end wall facing the front opening surface of the nozzle hole, and the end axis of the nozzle member passes through the end wall. A plurality of gas fuel injection holes that open around the nozzle holes are provided, so that the sprayed fuel from the plurality of gas fuel injection holes forms a spray foam that diffuses without colliding with the inner wall of the intake pipe. It is supplied to the engine while mixing well with the intake air flowing down, improving the combustion efficiency.

  In addition, if noise is generated in the nozzle hole during this period, most of the noise is blocked by the portion of the end wall of the nozzle cap where there is no gas fuel injection hole, and leakage from the nozzle member is suppressed. The quietness of the valve can be achieved.

  According to the second aspect of the present invention, the fuel injected from the plurality of gas fuel injection holes forms a diverging spray foam and forms an ideally diffused spray foam without colliding with the inner wall of the intake pipe. Can be mixed with intake air.

  According to the third aspect of the present invention, it is possible to satisfy the sound insulation effect due to the diffusion of the injected fuel through the gas fuel nozzle hole and the end wall while avoiding the decrease in the gas fuel flow rate due to the pressure loss at the gas fuel nozzle hole. .

  According to the fourth feature of the present invention, the noise reflected on the inner surface of the end wall of the nozzle cap is concentrated in the center of the nozzle hole and attenuates each other, thereby reducing the silence of the gas fuel injection valve. Can be increased.

  According to the fifth aspect of the present invention, the nozzle cap cooperates with a ring body fixed to the nozzle member to play a role of holding the O-ring in close contact with the inner surface of the mounting hole of the intake pipe. It can also contribute to the simplification of the hole seal structure.

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 taken along arrow 2 in FIG. 1. FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to 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 has a front end portion attached to a mounting hole Ea provided in a pipe wall of an intake pipe E of the engine, and gas fuel is fed into the intake pipe E during the intake stroke of the engine. Inject directly. The gas fuel injection valve I includes a cylindrical first housing portion 3 and a cylinder having a larger diameter than the first housing portion 3, the front end portion of which is caulked and joined to a flange 3 a at the rear end of the first housing portion 3. A valve housing 2 comprising a cylindrical second housing part 4 and a cylindrical third housing part 5 having a smaller diameter than the second housing part 4 and integrally connected to the rear end wall 4a of the second housing part 4 The inside of the valve housing 2 is a gas fuel passage 6. 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.

  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, a throttle hole 46 having a smaller diameter connected to the outlet of the valve hole 45, A nozzle hole 48 having a diameter larger than that of the throttle hole 46 is provided at the outlet of the throttle hole 46 through a tapered annular step 47.

On the other hand, the valve body 15 is slidably accommodated 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 that ends from the rear end surface in front of the flange portion 16 and a plurality of horizontal holes 31 that 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 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.

  Further, a rubber-made annular cushion member 43 facing the front end surface of the fixed core 29 is joined to the rear end surface of the valve body 15 by baking.

  A nozzle cap 50 is fitted to the front end portion of the nozzle member 11. The nozzle cap 50 includes a cylindrical portion 52 that is snap-coupled to the first locking groove 51 on the outer peripheral surface of the front end portion of the nozzle member 11, and a front opening surface of the nozzle hole 48 that is connected to the front end of the cylindrical portion 52. And an end wall 53 opposed to the cylindrical portion 52 and a flange 54 extending in the radial direction from the rear end of the cylindrical portion 52, and the whole is integrally formed of synthetic resin.

  The end wall 53 has a conical shape having an apex P on the central axis Y of the nozzle member 11 on the front side thereof, and the end wall 53 is arranged in such a manner that the central axis Y of the nozzle member 11 is sandwiched between the end walls 53. A pair of gas fuel injection holes 55, 55 opening in the hole 48 is provided. These gas fuel injection holes 55, 55 are arranged so that the respective central axes A, A are orthogonal to the conical bus line of the end wall 53. Therefore, the central axes A and A of the gas fuel injection holes 55 and 55 are inclined so as to be separated from the central axis Y of the nozzle member 11 as going forward.

  A synthetic resin ring body 57 disposed behind the flange 54 is snap-coupled to the second locking groove 56 on the outer peripheral surface of the intermediate portion of the nozzle member 11, and the nozzle body and the flange 54 allow the nozzle to be connected to the nozzle member 11. A seal groove 58 that faces the outer peripheral surface of the member 11 is defined. The O-ring 59 that comes into close contact with the inner peripheral surface of the seal member 58 when the nozzle member 2 is inserted into the mounting hole Ea of the intake pipe E of the engine. Is installed.

  Further, in the annular seal groove 61 formed on the outer peripheral surface of the rear end portion of the third housing portion 5, when the fuel distribution pipe D is fitted on the outer periphery of the third housing portion 5, it is in close contact with the inner peripheral surface. A ring 62 is attached.

  Next, the operation of the first 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 fuel distribution pipe D flows into the inlet hole 36 of the valve housing 2 and is filtered by the fuel filter 39, and inside the pipe-shaped retainer 37, the valve body. It waits in the guide hole 9 through the 15 vertical holes 30 and the horizontal holes 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 3 a, and the valve body 15. As the rubber cushion member 43 of the valve body 15 is sucked 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 with respect 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 through the nozzle hole 48, a pair of nozzle caps 50. The gas fuel injection holes 55 and 55 are injected into the intake pipe E. At this time, since the central axes A, A of the pair of gas fuel injection holes 55, 55 are inclined away from the central axis Y of the nozzle member 11 as going forward, the gas fuel injection holes 55, 55 are separated from the pair of gas fuel injection holes 55, 55. The sprayed fuel forms a divergent spray foam and diffuses ideally without adhering to the inner wall of the intake pipe E. Therefore, the injected fuel is supplied to the engine while being well mixed with the intake air flowing down the intake pipe E. Efficiency can be increased.

  During this time, if noise is generated in the nozzle hole 48 due to separation of the flow of gas fuel generated in the annular step 47 between the throttle hole 46 and the nozzle hole 48, most of the noise is generated by the end wall of the nozzle cap 50. Therefore, the gas fuel injection valve I is prevented from leaking out of the nozzle member 11 by being blocked at the portion where the gas fuel injection holes 55, 55 are not provided, and the quietness of the gas fuel injection valve I can be achieved.

  In particular, since the end wall 53 has a conical shape having the apex P on the front side, the noise reflected on the inner surface of the end wall 53 concentrates on the center of the nozzle hole 48 and attenuates each other. Thus, the silence of the gas fuel injection valve I can be improved.

  In addition, the nozzle cap 50 cooperates with the ring body 57 fixed to the nozzle member 11 to hold an O-ring 59 that is in close contact with the inner surface of the attachment hole Ea of the intake pipe E, and seals the attachment hole Ea. It can also contribute to simplification of the structure.

  Next, a second embodiment of the present invention shown in FIG. 3 will be described.

  In the second embodiment, four gas fuel injection holes 55, 55... Arranged at equal intervals around the axis Y of the nozzle member 11 are provided on the end wall 53 of the nozzle cap 50. Since it is the same as that of the previous embodiment, the same reference numerals are given to the same parts in FIG. 3 as those of the previous embodiment, and redundant description is omitted.

  According to the second embodiment, the gas fuel that has passed through the nozzle hole 48 is injected from the four gas fuel injection holes 55, 55. Thus, the mixing with the air in the intake pipe E can be made better.

  By the way, if the number of the gas fuel injection holes 55 is increased, the inner diameter of each gas fuel injection hole 55 is inevitably reduced, and if the inner diameter becomes a certain value or less, the flow rate is reduced due to pressure loss. . Therefore, in order to satisfy the sound insulation effect due to the diffusion of the injected fuel by the gas fuel nozzle 55 and the end wall while avoiding the decrease in the flow rate of the gas fuel due to the pressure loss at each gas fuel nozzle 55, the Experiments have shown that the number is preferably 2 to 6.

  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. For example, the ring body 57 can be formed integrally with the nozzle member 11. Further, the plurality of gas fuel injection holes 55 can be arranged at irregular intervals around the axis Y of the nozzle member 11.

I ... Gas fuel injection valve 2 ... Valve housing 6 ... Gas fuel passage 11 ... Nozzle member 13 ... Valve seat 13 ... Valve seat 15 .... Valve body 45 ... Valve hole 46 ... Restriction hole 48 ... Nozzle hole 50 ... Nozzle cap 53 ... End wall 54 ... Flange 55 ... .... Gas fuel injection hole 57 ... Ring body 58 ... Seal groove 59 ... Seal member (O-ring)

Claims (5)

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), and a nozzle hole (48) having a larger diameter connected to the outlet of the throttle hole (46). A gas fuel injection valve that directly injects gas fuel from the nozzle member (11) into the intake pipe (E) of the engine,
A nozzle cap (50) attached to the front end portion of the nozzle member (11) passes through an end wall (53) facing the front opening surface of the nozzle hole (48) and the end wall (53). A gas fuel injection valve comprising a plurality of gas fuel injection holes (55) that open to the nozzle hole (48) around a central axis (Y) of the nozzle member (11). The gas fuel injection valve according to claim 1,
Each of the gas fuel injection holes (55) is formed so as to incline in a direction away from the central axis (Y) of the nozzle member (11) as its central axis (A) goes in front of the nozzle cap (50). An injection valve for gas fuel, characterized by The fuel injection valve for gas fuel according to claim 1 or 2,
2. A gas fuel injection valve, wherein the number of the gas fuel injection holes (55) is 2 to 6. The gas fuel injection valve according to claim 1,
An injection valve for gas fuel, wherein the end wall (53) is formed in a conical shape having a vertex (P) on the front side thereof. The gas fuel injection valve according to claim 1,
The nozzle member (11) includes a flange (54) formed on the nozzle cap (50) and a ring body (57) formed on the outer periphery of the nozzle member (11) behind the nozzle cap (50). When the nozzle member (11) is inserted into the mounting hole (Ea) of the intake pipe (E) of the engine, the seal groove (58) facing the outer peripheral surface of A gas fuel injection valve comprising a seal member (59) that is in close contact with the inner peripheral surface of the mounting hole (Ea).

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