JPH0219649A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To make a fuel injection valve simple in structure, dispense with any high-grade machining and there are variations in each product as well as to make it spray such fuel as improved in atomization by installing an atomizing member with an inner chamber, a projection and a spray port at the tip. CONSTITUTION:An atomizing member 60 is set up in the tip of a fuel injection valve 1. This atomizing member 60 has an inner chamber 62 where an injection nozzle 14 is opened at the side of the injection valve 1. In addition, in this inner chamber 62, it has a sectional area narrower than an opening area of the nozzle 14 concentric with a center shaft of the nozzle 14, and also has a columnar projection 64 formed projectingly in opposition to the nozzle 14 at a constant distance. In addition, it has plural numbers of spray nozzles 66 formed in the circumference of the columnar projection 64 in the inner chamber 62. With this constitution, fuel sprayed out of the nozzle 14 of the hole-type fuel injection valve 1 collides with the columnar projection 64 and is atomized and, after being improved in atomization, it is sprayed out of the spray nozzle 66.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel injection valve for supplying fuel to an internal combustion engine.

[Prior art]

Conventionally, there are two types of fuel injection valves: a pintle type that has a pintle at the tip of the needle valve that protrudes from the injection hole, and a hole type that does not have a pintle at the tip of the needle valve. In addition, compared to the Vintorquive, hole-type fuel injection valves are easier to process at the tip of the needle valve.
It has the advantage that there is little influence on the injection quantity characteristics when foreign matter or dirt adheres to the injection hole. However, the Hall type is inferior to the Vintle type in terms of spray atomization, which is one of the most important characteristics for a fuel injector. In other words, in the case of the bottle type, the injected fuel is torn into hollow conical thin films by the bottle, effectively atomizing the fuel, but in the case of the hole type, the fuel is injected directly from the injection hole, so the Sallator average In terms of particle size, the atomized particle size of the Hall type is 3 to 4 times larger than the atomized particle size of the Vintorquive. As a hole-type fuel injection valve that solves this problem, Nippondenso Publication Technical Report No. 53-117 has been published, and its contents will be explained below. An adapter is provided downstream of the nozzle hole at the tip of the body of the electromagnetic fuel injection valve, and this adapter is provided with an umbrella-shaped jet impingement object. The umbrella-shaped jet colliding object is integrally fixedly supported on the cylindrical portion of the adapter by a plurality of ridges. With this configuration, the fuel jet injected from the nozzle hole is formed into a conical thin film shape by the umbrella-shaped jet colliding object.
As a result of being torn apart by the gaps, the atomization of the ejected fuel is promoted. In this hole-type fuel injection valve, the fuel jet injected from the nozzle hole is further atomized when it is ejected from the gap, and it is clear that the fuel jet is atomized when it is ejected from the gap. The convex shape of the jet colliding object is large, and it is the conical surface of the umbrella-shaped jet colliding object that promotes atomization of the fuel, and the circular 0°5M formed by the skirt and the cylindrical part of the adapter. There is a certain amount of gap.

[Problem to be solved by the invention]

In general, Hall type fuel injection valves eject a larger spray particle size than bottle type fuel injection valves, so when starting a cold engine, etc., the amount of HC in the exhaust gas may increase. There were problems with poor emissions and a large amount of HC components adhering to the spark plug, causing the spark plug to smolder. In addition, in the hole-type fuel injection valve described in the above-mentioned technical report, in order to obtain the desired spray particle size, a circular 0.5 mm diameter formed by the skirt of the umbrella-shaped jet colliding object and the cylindrical portion of the adapter is required. The manufacturing dimensional accuracy of the gap of about 5 carp has a large effect. In other words, dimensional control during processing etc. is important.
When this gap varies, there is a problem in that the spray particle size varies from product to product. The present invention has been made to solve the above-mentioned problems, and its purpose is to simply add a separate spray member provided downstream of the injection hole of a hole-type fuel injection valve. To provide a hole-type fuel injection valve that can inject fuel that is sufficiently atomized and atomized without the need for advanced machining, has a uniform configuration, and has no variation from product to product. .

[Means to solve the problem]

The structure of the invention for solving the above problems is a hole-type fuel injection system that includes a valve member, a valve seat on which the valve member is seated, and a valve body having an injection hole continuous to the downstream side of the valve seat. In the valve, a spray member is disposed at the tip of the fuel injection valve, and the spray member has an inner chamber in which the injection hole opens on the side of the injection valve, and a central axis of the injection hole in the inner chamber. a protrusion that is coaxial with the injection hole, has a cross-sectional area narrower than the opening area of the injection hole, is spaced apart from the injection hole by a certain distance, and is formed to protrude opposite the injection hole; It is characterized by having a plurality of spray holes formed around the protrusion.

[Effect]

Fuel injected from the injection hole of a hole-type fuel injection valve collides with a protrusion formed in a protruding manner opposite to the injection hole of a spray member disposed at the tip of the injection valve, resulting in improved atomization and atomization. Then, the spray is sprayed from a plurality of spray holes formed around the protrusion at the bottom.

【Example】

The present invention will be described below based on specific examples. FIG. 1 shows a fuel supply system suitable for use in a vehicle, for example, in which an electromagnetic fuel injection valve 1 for an internal combustion engine according to an embodiment of the present invention is incorporated. The fuel supply system has a fuel tank 2, and the fuel that is pumped from the fuel tank 2 by an electromagnetic pump 3 passes through a filter 4 and is sent to a supply path 6. It is sent to the control valve 7. And supply route 6
The pressurized fuel inside is sent to the inlet 9 of the fuel injection valve 1 through the branch pipe 8. The electromagnetic fuel injection valve l according to the invention generally supplies fuel into the intake pipe of a spark-ignition internal combustion engine. The fuel used is gasoline, which has a relatively low vapor pressure. The supply pressure of this fuel is relatively low, about 250 kPa. Further, this supply pressure is regulated to a constant differential pressure with respect to the pressure in the intake pipe by a pressure control valve 7. The electromagnetic fuel injection valve 1 has a valve body 11 and a valve case 12, and the valve body 1 is assembled by caulking the tip 19 of the valve case 12.
1, the valve body 11 and valve case 1 are
2 are integrally connected. A guide hole 17 is formed in the valve body 11, and the guide hole 17
The elongated needle-type valve member 20 housed in is provided with two sliding parts 21 and 22, and these sliding parts 21 and 22 are arranged on the wall surface of the guide hole 17 in order to smoothly slide the valve member 20. They are fitted so that there is a gap of several inches between them. A disk-shaped stopper 31 is interposed and fixed between the rear end of the valve member 20 and the valve case 12, and when the flange 32 provided on the valve member 20 comes into contact with the stopper 31, the valve member 20 is moved to the open position. is now determined. The rear end portion of the valve member 20 passes through the stopper 31 and extends into the armature 36 of the valve case 12. Inside the valve case 12, a valve member 20 is driven and the valve member 2 is inserted into the valve case 12.
An electromagnetic actuator 35 is provided for moving the 0 between closed and open positions. The electromagnetic actuator 3
5 is an armature 36 connected to the rear end of the valve member 20
and a stator 37 mounted in a fixed relationship to the valve case 12 and therefore in a fixed relationship to the valve body 11, and an electromagnetic coil 38 wound around the stator 37. are doing. The armature 36 is urged toward the closed position by a return coil spring 39, that is, downwardly in FIG. 1, and the electromagnetic coil 38
When a current is supplied to , an electromagnetic force is generated, and this electromagnetic force attracts the armature 36 toward the stator 37 against the biasing force of the coil spring 39, and the flange 32 comes into contact with the stopper 31, causing the valve member to close. 20 occupies the open position. When the supply of current to the electromagnetic coil 38 is stopped, the valve member 20 is moved away from the stator 37 by the urging force of the return coil spring 39, and the seal portion 23 of the valve member 20 comes into contact with the valve seat 16. By the valve member 2
0 occupies the closed position. The electromagnetic coil 38 is connected to an electronic control circuit 42 including a microcomputer via a terminal 41, and the electronic control circuit 42 controls supply and termination of current to the electromagnetic coil 38. The stator 37 is integrally provided with a flange 43, which is fixedly attached to the rear end of the valve case 12. A joint portion 4 connected to the branch pipe 8 from the end face of the flange 43 on the opposite side to the stator 37
A filter 46 is disposed within the joint portion 44, and an adjusting vibrator 47 for adjusting the biasing force of the return coil spring 39 is disposed. The upstream end of the internal passage 48 of the adjusting vibe 47 is connected to the joint portion 44.
The downstream end of the internal passageway 48 is connected to the internal space 52 through an opening 50 of the armature 36.
is connected to. Further, as shown in FIGS. 2 and 3, a spray member 60
is integrally connected to the valve body 11 of the fuel injection valve 1 by caulking and pressing the tip 61 of the spray member 60 against the valve body 11 of the fuel injection valve 1. The spray member 60 has an inner chamber 62 formed therein, and the injection hole 14 of the valve body 11 is opened in the upper part of the inner chamber 62. On the central axis of the injection hole 14 and at the bottom of the inner chamber 62, an injection hole 14 is opened. Hole 14
A columnar projection 64 is provided opposite to the columnar projection 64 .
A plurality of (three holes in this embodiment) spray holes 6B are arranged around the columnar projection 64 at equal angles on the same pitch circle diameter.
- is provided. Next, the operation of the present injection valve 1 will be explained. When no current is supplied from the electronic control circuit 42 to the electromagnetic coil 38 of the electromagnetic actuator 35, the valve member 20 occupies the closed position by the biasing force of the return coil spring 39, and in the closed position, the sealing portion of the valve member 20 closes. 23 contacts the valve seat 16 of the valve body 11, stopping the supply of fuel to the internal combustion engine. When electric current is supplied from the electronic control circuit 42 to the electromagnetic coil 38, the valve member 20 is attracted to the stator 37 against the urging force of the return coil spring 39, and moves until the flange 32 comes into contact with the stopper 31. Valve member 20 occupies an open position. The pressurized fuel from the branch pipe 8 is passed through the filter 46, the internal passage 48 of the adjusting vibe 47, and the armature 36.
opening 50. The internal space 52 of the armature 36 , the fuel passage 54 of the valve member 20 , the outer circumference of the flange 32 of the valve member 20 , the seal portion 23 of the valve member 20 and the valve seat 1 of the valve body 11
6 and through the injection hole 14 into the inner chamber 62 of the spray member 60. Next, the operation of the spray member 60 will be described with reference to FIGS. 2 and 3. The fuel jet injected from the injection hole 14 provided in the valve body 11 of the fuel injection valve 1 into the inner chamber 62 of the spray member 60 provided downstream of the injection hole 14 collides with the columnar protrusion 6 which is the colliding portion of the spray member 60.
4, the particles are sufficiently atomized and atomized to a spray particle size required by the engine, and then from a plurality of spray holes 66 downstream thereof into the intake pipe or cylinder (not shown), as described below. The spray is adjusted to the spray angle required by the engine and injected. According to experiments conducted by the inventors, the spray particle size at this time is determined by the ratio a/d of the tip diameter a of the columnar protrusion 64 and the diameter d of the injection hole 14, and the total cross-sectional area of the plurality of spray holes 66 n·πA3/ 4 and the ratio n(A/d)2 of the cross-sectional area πd2/4 of the injection hole 14, and the graphs shown in FIGS. 4 and 5 were obtained. These graphs show that when a/d is 0.5 or less and n(A/d)2 is 20 or more, the spray particle size required by the engine can be achieved. Further, according to the studies conducted by the inventors, it was confirmed that the number of spray holes 66 is about three (n=3), and it is possible to provide the fuel injection valve 1 with sufficiently improved atomization. Further, according to experiments conducted by the inventors, the fuel metered at the injection hole 14 is distributed between the injection hole 14 and the columnar protrusion 64 as shown in FIG.
When the distance from the
It has been found that spraying can be performed from a plurality of spray holes 66 without impairing metering accuracy. According to the experiments conducted by the inventors, the spray angle was determined by the columnar projection 64.
It has been found that this is regulated by a plurality of spray holes 66 provided downstream of. In other words, the spray that collides with the columnar protrusion 64 and is dispersed hits the inner wall of the spray hole 66 at an angle β as shown in FIG.
8, and is injected into the outside space along the inner wall 68 of the spray hole 66 by a length f. However, the angle β at this time is determined hydrodynamically and a/d=1
−cosβ+(sinβ/π)・log ((1+si
It is given by β that satisfies nβ)/(1-5inβ)). It turns out that the spray angle is determined by this length f, and the seventh
The graph in Figure was obtained. From this graph, 0.6≦f≦
It can be seen that by setting the length f to 2.0, it is possible to set the spray angle so that the fuel does not adhere to the intake pipe wall as required by the engine. As mentioned above, the atomization of the spray of the fuel injection valve of this example,
Atomization is improved by the geometric dimensions of the columnar projections 64 formed in the inner chamber 62 and the injection holes 14. Since it is determined, only the machining dimensions of the columnar protrusion 64 need be managed, and the machining is easy.

【Effect of the invention】

As explained above, according to the present invention, a simple configuration in which a spray member having an inner chamber, a protrusion, and a spray hole is provided at the tip of a fuel injection valve can be used for each product without requiring sophisticated machining. This has the excellent effect of being able to inject fuel that is sufficiently atomized and atomized without any variation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a fuel injection valve according to a specific embodiment of the present invention. FIG. 2 is a partially enlarged vertical cross-sectional view of the tip of the fuel injection valve shown in FIG. FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. 2. FIG. 4 shows a/a in the fuel injection valve according to the present invention.
Graph showing changes in spray particle size versus d. FIG. 5 is a graph showing the change in spray particle size with respect to n(A/d)2 in the fuel injection valve according to the present invention. Figure 6 shows angle β, point P
1 is a partially enlarged vertical cross-sectional view similar to FIG. 2 for explaining the relationship between length f; FIG. 7 is a graph showing the change in spray angle with respect to f in the fuel injection valve according to the present invention. 1 Fuel injection valve 11 Valve body 12 Valve case 14
Injection hole 16 Valve seat 20 Valve member 23 Seal portion 3
5 Electromagnetic actuator filter columnar projection spray member spray hole inner chamber

Claims (1)

[Claims] In a hole-type fuel injection valve comprising a valve member, a valve seat on which the valve member is seated, and a valve body having an injection hole connected to the downstream side of the valve seat, the tip of the fuel injection valve is provided with a spray. A member is disposed, and the spray member has an inner chamber in which the injection hole opens on the side of the injection valve, and is coaxial with the central axis of the injection hole in this inner chamber and has an area larger than the opening area of the injection hole. a projection having a narrow cross-sectional area and protruding from and facing the injection hole at a certain distance from the injection hole; and a plurality of spray holes formed around the projection in the inner chamber. A fuel injection valve characterized by having: