JP3687125B2 - Fuel injection nozzle for internal combustion engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a fuel injection device for an internal combustion engine, for example, an injection nozzle portion of an electromagnetic fuel injection valve for injecting and supplying fuel to an internal combustion engine for an automobile.
[0002]
[Prior art]
2. Description of the Related Art Generally, a fuel injection valve used in an internal combustion engine (hereinafter referred to as “engine”) accommodates a valve member in a guide hole formed in the axial direction of the valve body so as to be slidable back and forth. The nozzle hole is opened and closed by the vertical movement of the valve member. For this reason, the lift amount at the time of valve opening of the valve member is precisely controlled so as to ensure an appropriate fuel injection amount.
[0003]
The fuel injection valve disclosed in Japanese Patent Laid-Open No. 6-501087 has a porous orifice plate at the outlet of the injection hole of the fuel injection valve, and fuel flows through a thick support plate to prevent distortion of the orifice plate. The support plate is fixed to the valve body by welding together with the orifice plate.
[0004]
[Problems to be solved by the invention]
However, according to the shape of the conventional orifice plate, since the heat is easily maintained at the tip of the fuel injection valve, when the fuel injection valve itself is exposed to a high temperature environment, the fuel injection valve The fuel vapor generated inside hinders the flow of fuel in the fuel passage inside the fuel injection valve, the injection amount decreases drastically when the engine is restarted at a high temperature, causing engine rough idle and engine stall. There is a problem that the drivability of the vehicle becomes unstable.
[0005]
The objective of this invention is providing the fuel-injection nozzle for internal combustion engines which improved the cooling effect of the fuel-injection valve at the time of high temperature environment.
Another object of the present invention is to provide a fuel injection nozzle for an internal combustion engine that can stably supply fuel when the engine is restarted at a high temperature.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a fuel injection nozzle for an internal combustion engine according to the present invention includes, in claim 1, a valve body having a cylindrical hole and a conical inclined surface formed on the inlet side of the cylindrical hole,
A valve member capable of contacting a part of the conical slope, and a valve member capable of contacting and separating from the part of the conical slope;
An orifice plate joined to the outlet surface of the cylindrical hole of the valve body by welding, and having an orifice communicating with the cylindrical hole and penetrating in the plate thickness direction;
The orifice plate is formed integrally with the orifice plate, extends in the axial direction from the outer periphery of the orifice plate, forms a substantially U-shaped cup shape together with the orifice plate, and has an inner circumferential surface in a space in which fuel is injected through the orifice. Exposed cooling fins,
A resin sleeve in which one end is fixed to the valve body so as to cover the outer peripheral side of the cooling fin, and a bent portion is formed on the outlet side of the other end to be bent radially inward so as to wrap the orifice plate inside ; equipped with a,
The cooling fin employs a configuration characterized in that its tip end portion extends in the axial direction along the resin sleeve so as to face the bent portion .
[0007]
The fuel injection nozzle for an internal combustion engine according to claim 2 is characterized in that, in the configuration, the resin sleeve is press-fitted or fitted to an outer periphery of the cooling fin.
The fuel injection nozzle for an internal combustion engine according to claim 3, wherein the resin sleeve is press-fitted or fitted to an outer periphery of the valve body.
[0008]
A fuel injection nozzle for an internal combustion engine according to a fourth aspect of the present invention is characterized in that, in the configuration, the resin sleeve is press-fitted or fitted into the valve body and the cooling fin.
6. The fuel injection nozzle for an internal combustion engine according to claim 5, wherein in the configuration, the cooling fin has a circumferential surface so that a contact area with the fuel spray is increased so that cooling is promoted by the spray of fuel injected from the orifice. It is characterized by being uneven in the direction.
[0009]
[Operation and effect of the invention]
According to the fuel injection nozzle for an internal combustion engine according to claim 1 of the present invention, the cooling fin having a large contact area with the air in the injection space at the tip of the fuel injection valve is provided. This promotes cooling of the valve portion of the fuel injection valve. Therefore, the amount of fuel vapor generated in the internal passage of the fuel injection valve can be reduced, so that the actual injection amount is prevented from lowering than the fuel injection amount required by the engine at high temperature restarts, etc., and the fuel injection amount is started properly. It can be secured as much as possible, keep the idling state stable, prevent rough idle, and further prevent engine stall.
[0010]
Therefore, when the engine starts at a high temperature, it is possible to reduce the state in which the required fuel amount is insufficient at the beginning of the start and secure the fuel injection amount, thereby ensuring an appropriate engine start and an idling state immediately after the start.
According to the fuel injection nozzle for an internal combustion engine according to claim 2, 3 or 4, since the resin sleeve is press-fitted or fitted to the outer periphery of one or both of the valve body and the cooling fin, the resin sleeve is made by a simple method. The sleeve can be fixed to the valve body.
[0011]
According to the fuel injection nozzle for an internal combustion engine according to claim 5, the cooling fin is uneven in the circumferential direction so that the contact area with the fuel spray is increased so that cooling is promoted by the spray of fuel injected from the orifice. Since it is formed, cooling of the cooling fins is promoted, and the cooling efficiency of the fuel in the vicinity of the valve portion inside the valve body is improved, so that the amount of fuel vapor generated can be reduced.
[0012]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
1 to 4 show an embodiment in which the present invention is applied to a fuel injection valve of a fuel supply device for a gasoline engine.
[0013]
First, a fuel injection valve as a fuel injection device for an internal combustion engine will be described with reference to FIG. As shown in FIG. 2, a fixed iron core 21, a spool 91, an electromagnetic coil 32, a coil mold 31, and metal plates 93 and 94 as magnetic paths are integrally formed in a resin housing mold 11 of the fuel injection valve 10. Has been.
The fixed iron core 21 is made of a ferromagnetic material and is provided in the housing mold 11 so as to protrude from above the coil mold 31. An adjusting pipe 29 is fixed to the inner wall of the fixed iron core 21.
[0014]
The electromagnetic coil 32 is wound around the outer periphery of the resin spool 91, and then the coil mold 31 is resin-molded around the outer periphery of the spool 91 and the electromagnetic coil 32, and the electromagnetic coil 32 is surrounded by the coil mold 31. The coil mold 31 protects the cylindrical tubular portion 31a that protects the electromagnetic coil 32 and the lead wire that is electrically derived from the electromagnetic coil 32, and also retains the terminal 34 that will be described later. Projecting portion 31b projecting upward from the top. Then, the spool 91 and the electromagnetic coil 32 are mounted on the outer periphery of the fixed iron core 21 in an integrated state by the coil mold 31.
[0015]
The two metal plates 93 and 94 are provided such that one upper end is in contact with the outer periphery of the fixed core 21 and the other lower end is in contact with the outer periphery of the magnetic pipe 23, and a magnetic flux that passes the magnetic flux when the electromagnetic coil 32 is energized. It is a member that forms a path, and is covered on the outer periphery of the cylindrical portion 31a so as to sandwich the cylindrical portion 31a from both sides. The electromagnetic coil 32 is protected by the two metal plates 93 and 94.
[0016]
A connector portion 11 a is provided above the housing mold 11 so as to protrude from the outer wall of the housing mold 11. A terminal 34 electrically connected to the electromagnetic coil 32 is embedded in the connector portion 11 a and the coil mold 31. The terminal 34 is connected to an electronic control device (not shown) via a wire harness.
[0017]
One end of the compression coil spring 28 is in contact with a spring seat surface provided on the movable iron core 22, and the other end of the compression coil spring 28 is in contact with the bottom of the adjusting pipe 29. The compression coil spring 28 urges the movable iron core 22 and the needle 25 downward in FIG. 2 so that the seat portion of the needle 25 is seated on the valve seat 263 of the valve body 26. When an exciting current flows from the terminal 34 to the electromagnetic coil 32 through the lead wire by an electronic control device (not shown), the needle 25 and the movable iron core 22 are attracted toward the fixed iron core 21 against the urging force of the compression coil spring 28. The
[0018]
The nonmagnetic pipe 24 is connected to the lower part of the fixed iron core 21. Then, one end 24 a is connected to the lower part of the fixed iron core 21 so as to partially protrude from the lower end of the fixed iron core 21. Further, a small diameter portion 23b of a magnetic pipe 23 made of a magnetic material and formed in a stepped pipe shape is connected to the lower end of the other end portion 24b of the nonmagnetic pipe 24. The other end 24 b of the nonmagnetic pipe 24 forms a guide for the movable iron core 22.
[0019]
Next, a movable iron core 22 made of a magnetic material and formed in a cylindrical shape is provided in the internal space of the nonmagnetic pipe 24 and the magnetic pipe 23. The outer diameter of the movable iron core 22 is set slightly smaller than the inner diameter of the other end 24 b of the nonmagnetic pipe 24, and the movable iron core 22 is slidably supported by the nonmagnetic pipe 24. The upper end surface of the movable iron core 22 is provided so as to face the lower end surface of the fixed iron core 21 with a predetermined gap.
[0020]
A joint 43 is formed on the needle 25. And the junction part 43 and the movable iron core 22 are laser-welded, and the needle 25 and the movable iron core 22 are connected integrally. A double chamfering as a fuel passage is provided on the outer periphery of the joint portion 43.
Above the fixed iron core 21 is provided a filter 33 that removes foreign matters such as dust in the fuel that is pumped from the fuel tank by a fuel pump or the like and flows into the fuel injection valve 10.
[0021]
The fuel that has flowed into the fixed iron core 21 through the filter 33 passes through the gap between the adjusting pipe 29 and the two chamfered portion formed in the joint portion 43 of the needle 25, and further the sliding between the cylindrical surface 261 of the valve body 26 and the needle 25. A cylinder that passes through a gap between the four chamfered portions formed in the moving portion 41 and reaches a valve portion that includes a contact portion 251 and a valve seat 263 at the tip of the needle 25, and forms a cylindrical hole 8 from the valve portion. The surface 264 is reached.
[0022]
Next, the structure of the discharge part 50 of the fuel injection valve 10 is demonstrated based on FIG.
Inside the large-diameter portion 23a of the magnetic pipe 23, a valve body 26 is inserted through a hollow disk-shaped spacer 27 and laser-welded. The thickness of the spacer 27 is adjusted so as to maintain the air gap between the fixed iron core 21 and the movable iron core 22 shown in FIG. 2 at a predetermined value. A cylindrical surface 261 on which the sliding portion 41 of the needle 25 slides and a valve seat 263 on which the conical contact portion 251 of the needle 25 is seated are formed on the inner wall of the valve body 26. Further, a cylindrical hole 8 formed by a cylindrical surface 264 is provided at the bottom center of the valve body 26.
[0023]
A flange 36 is formed on the needle 25 so as to be opposed to the lower end surface of the spacer 27 accommodated in the inner wall of the large-diameter portion 23a of the magnetic pipe 23 with a predetermined gap. The flange 36 is formed on the contact portion 251 side formed at the tip of the needle 25 in the entire length of the needle 25, and can slide on a cylindrical surface 261 formed on the valve body 26 below the flange 36. A sliding portion 41 is formed.
[0024]
A flow control mechanism 51 is provided at the outlet of the cylindrical hole 8 of the valve body 26. As shown in FIG. 1, the flow control mechanism 51 is configured by the shapes, positions, combinations thereof, and the like of the needle 25, the valve body 26 and the orifice plate 52. Each of these features will be described sequentially. (1) As shown in FIG. 1, the needle 25 has a spherical surface 255 formed at the tip thereof. FIG. 1 shows a valve-closed state. In this valve-closed state, the contact portion 251 and the valve seat 263 serve as contact points, and the aggregate of the contact points is an annular line. (2) The valve body 26 includes the cylindrical surface 261, the conical slope 262, and the cylindrical surface 264 forming the cylindrical hole 8 shown in FIG. 1, and the boundary lines of these surfaces 261, 262, and 264 are circular. Yes. (3) The orifice plate 52 is made of, for example, stainless steel, constitutes a part of the flow control mechanism 51, and is joined to the tip of the valve body 26 by welding, for example, all-around welding. The orifice plate 52 is formed with four orifices 54, 55, 56 and 57 (55 and 57 not shown) penetrating in the plate thickness direction.
[0025]
Next, the cooling mechanism 81 for the orifice plate will be described.
The orifice plate 52 constituting the cooling mechanism 81 functions as a cooling fin and is made of a metal having good thermal conductivity, for example, stainless steel. The orifice plate 52 includes a plate portion 61 and a cylindrical portion 62, and is integrally formed in a cup shape. The outermost diameter of the cylindrical portion 62 is set to be equal to the outer diameter of the valve body 26. The cylindrical portion 62 has a function of a cooler, contacts the inside air of a passage communicating with the engine intake passage, and exhibits a cooling effect when the valve body 26 of the fuel injection valve 10 is exposed to a high temperature environment.
[0026]
The sleeve 71 is made of resin, and has a projection 72 for fitting protruding from the inner peripheral wall on the one end mounting side. The projection 72 is fitted and coupled to a concave groove 73 formed on the outer periphery of the valve body 26 by press fitting. ing. On the other end outlet side of the sleeve 71, a bent portion 74 that is bent in an L shape radially inward is formed in an annular shape integrally with the sleeve 71. Since the bent portion 74 is bent in a direction in which the orifice plate 52 is enclosed, the bent portion 74 serves to protect the orifice plate 52.
[0027]
At the time of assembly, the orifice plate 52 is joined to the tip of the valve body 26 by welding, for example, all-around welding. Next, the sleeve 71 is inserted from the bottom to the top in FIG. 1 and pushed in until the convex portion 72 is fitted in the concave groove 73 of the valve body 26. At the time of pushing, the resin sleeve 71 is press-fitted into one of the outer periphery of the cylindrical portion 62 and the outer periphery of the valve body 26, or both the outer periphery of the cylindrical portion 62 and the outer periphery of the valve body 26.
[0028]
During the fuel injection operation, the valve opening operation is performed by separating the contact portion 251 of the needle 25 from the valve seat 263 of the valve body 26. During this valve opening operation, the fuel in the internal passage of the valve body 26 is opened. Flows into the cylindrical hole 8 formed by the cylindrical surface 264, and the direction is controlled by the orifices 54, 55, 56, 57, and the orifices 54, 55, 56, 57 are sprayed in a fan shape in this case in two directions. At this time, some of the mist-like particles of fuel adhere to the cylindrical portion 62 functioning as a cooling fin, and the cylindrical portion 62 and the plate portion 61 are cooled by the heat of vaporization of the fuel spray. Thereby, the valve body 26 and the needle 25 are cooled by the function as the cooling fin of the cooling mechanism including the cylindrical portion 62 and the plate portion 61. Therefore, the cooling effect after injection is exhibited.
[0029]
For example, when the engine is exposed to a high temperature environment, when the engine is restarted, the cylindrical portion 62 cooled by the fuel injected through the cylindrical hole 8 and the orifices 54, 55, 56, 57 when the valve is opened is relatively closer to the surroundings. The temperature is also low, and the heat of the valve body 26 is taken away, so that the generation of fuel vapor in the valve body 26 is suppressed, the fuel injection amount is prevented from drastically decreasing, and the fuel amount required by the engine is avoided. Maintains good engine performance when restarting at high temperatures.
[0030]
(Second embodiment)
A second embodiment of the present invention is shown in FIGS. The second embodiment shown in FIGS. 3 and 4 is an example in which an orifice plate 152 having a different shape is used in place of the orifice plate 52 described above.
The orifice plate 152 includes a plate portion 61 and a fin portion 153 that curves from the plate portion 61 into an L shape. The fin portion 153 is formed in an annular shape in an uneven shape in the circumferential direction, and an air layer 156 is formed between the recess 154 and the inner peripheral wall surface of the sleeve 71 as shown in FIG. Four air layers 156 are formed in the circumferential direction of the fin portion 153. The convex portion 155 that is convex when viewed from the outside of the diameter is press-fitted into the inner peripheral wall of the sleeve 71. Since the other components are the same as those of the first embodiment shown in FIG. 1, the description of the configuration and the operational effects of the other portions will be omitted.
[0031]
According to the second embodiment, when the fuel injection valve 10 is opened, the fuel injected from the cylindrical hole 8 through the orifices 54, 55, 56, 57 spreads in a fan shape and is injected radially from the opening of the sleeve 71. The At this time, the mist-like fuel injected from the orifices 54, 55, 56, 57 hits the inner wall of the concave portion 154 or the convex portion 155 of the cylindrical portion 153, and coupled with the material of the stainless steel orifice plate 152, this orifice plate Take heat away from 152. Therefore, the orifice plate 152 is relatively cooler than the ambient temperature, so that the orifice plate 152 performs a cooling action and cools the valve body 26 and the needle 25.
[0032]
In the second embodiment, in particular, the cylindrical portion 153 of the orifice plate 152 has an uneven shape in its circumferential direction, and the contact area with which the fuel spray contacts is formed relatively large. Since the amount of heat taken by the relatively low temperature fuel spray from the orifice plate 152 becomes relatively large, the orifice plate 152 acts as a cooling fin, and the cooling effect of the valve body 26 and the needle 25 by the cooling fin. Becomes big.
[0033]
In particular, the temperature of the valve body 26 and the needle 25 becomes relatively high due to heat transfer from an engine head (not shown), such as when the engine is restarted at high temperature, so that the fuel in the internal passage of the fuel injection valve 10 is hot. When the fuel vapor is generated, the orifice plate 152 functions as a cooling fin, and this cooling action suppresses the generation of the fuel vapor inside the fuel injection valve. Accordingly, since the amount of fuel vapor generated is relatively suppressed inside the fuel injection valve 10, the fuel flow immediately after the high temperature restart is ensured, and the cooling effect by the injected fuel is exerted on the orifice plate 152 by this fuel injection. The valve body 26 and the needle 25 are cooled by the cooling of the orifice plate 152. Therefore, when the engine is exposed to a high temperature environment, such as when restarting at a high temperature, there is an effect of preventing an extreme decrease in the injection amount and preventing deterioration of the engine performance.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an injection nozzle portion of a fuel injection nozzle for an internal combustion engine according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a fuel injection valve to which the present invention is applied.
FIG. 3 is a sectional view showing a nozzle portion of a fuel injection nozzle for an internal combustion engine according to a second embodiment of the present invention.
4 is a cross-sectional view taken along line IV-IV shown in FIG.
[Explanation of symbols]
8 injection hole (cylindrical hole)
10 Fuel injection valve 25 Needle (valve member)
26 Valve body (Valve body)
41 Sliding part 52 Orifice plate (cooling fin)
54, 56 Orifice 61 Plate part (cooling fin)
62 Cylindrical part 71 Resin sleeve 72 Convex part 73 Concave groove 74 Bent part 81 Cooling mechanism 152 Orifice plate 153 Fin part (cooling fin)
154 Concave portion 155 Convex portion 156 Air layer 264 Cylindrical surface

Claims (5)

A valve body having a cylindrical hole and a conical slope formed on the inlet side of the cylindrical hole;
A valve member capable of contacting a part of the conical slope, and a valve member capable of contacting and separating from the part of the conical slope;
An orifice plate joined to the outlet surface of the cylindrical hole of the valve body by welding, and having an orifice communicating with the cylindrical hole and penetrating in the plate thickness direction;
The orifice plate is formed integrally with the orifice plate, extends in the axial direction from the outer periphery of the orifice plate, forms a substantially U-shaped cup shape together with the orifice plate, and has an inner circumferential surface in a space in which fuel is injected through the orifice. Exposed cooling fins,
A resin sleeve in which one end is fixed to the valve body so as to cover the outer peripheral side of the cooling fin, and a bent portion is formed on the outlet side of the other end to be bent radially inward so as to wrap the orifice plate inside ; equipped with a,
The fuel injection nozzle for an internal combustion engine , wherein the cooling fin extends in the axial direction along the resin sleeve so that a tip portion thereof faces the bent portion .   The fuel injection nozzle for an internal combustion engine according to claim 1, wherein the resin sleeve is press-fitted or fitted to the outer periphery of the cooling fin.   The fuel injection nozzle for an internal combustion engine according to claim 1, wherein the resin sleeve is press-fitted or fitted to the outer periphery of the valve body.   The fuel injection nozzle for an internal combustion engine according to claim 1, wherein the resin sleeve is press-fitted or fitted into the valve body and the cooling fin.   The said cooling fin is formed in the uneven | corrugated shape in the circumferential direction so that a contact area with a fuel spray may become large so that cooling may be accelerated | stimulated by the spray of the fuel injected from the said orifice. The fuel injection nozzle for internal combustion engines as described in any one of -4.

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