JP2003161231A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reconcile both ways for atomization and spraying in a fuel injection valve having a nozzle plate with a plurality of injection holes, and to inhibit the attachment to a wall face by controlling a spraying pattern when mounted on an internal combustion engine. <P>SOLUTION: This fuel injection valve comprises a fluid passage plate 12 positioned at an inner side with respect to a contracted part of a valve member at a downstream side of the valve member with a valve seat 11a, and having an inner diameter part 13 for contracting a fuel fluid, and a nozzle plate 15 positioned at a downstream side of the fluid passage plate 12 and having a plurality of injection holes 16, and an injection hole pitch circle is located outside with respect to the inner diameter part 13 of the fluid passage plate 12. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for atomizing and injecting fuel and controlling the injection pattern thereof. In particular, the atomization of spray is high, and the injection has a low cost structure. The present invention relates to a fuel injection valve having a nozzle body.

[0002]

2. Description of the Related Art In order to improve fuel efficiency of an internal combustion engine and purify exhaust gas, it is important to promote further atomization of fuel injected from a fuel injection valve and to optimize injection direction. . As a fuel injection valve that can respond to this type of problem,
There is one that controls atomization and the injection direction by using a plate having a plurality of fine holes at the valve tip. As typical fuel injection valves thereof, Japanese Patent Laid-Open Nos. 2000-97129 and 2001
There is one disclosed in Japanese Patent Publication No. 46919. These prior arts focus on the fact that the turbulence in the fuel flow and the outflow velocity in the injection hole portion contribute to atomization. Therefore, the relationship between the distance between the valve member and the plate or the arrangement of the fine holes and the flow state upstream of the plate is optimized so that the atomized sprays do not overlap at the injection destinations and the two-way spray is performed. Is to get.

[0003]

In this type of fuel injection valve, it is generally known that the fuel spray atomizes when the injection hole diameter is reduced. However, it is necessary to increase the number of injection holes in order to obtain the required injection amount. As the number of injection holes increases, the distance between the injection holes becomes shorter, and coalescing of the injected fuel sprays easily occurs, which hinders atomization.

When applied to an internal combustion engine, it is necessary to optimize various injection amounts and spray patterns. That is, if the suppression of the fuel adhesion to the wall surface of the internal combustion engine is insufficient, the fuel adheres to the inner wall surface of the intake pipe, the piston, the cylinder wall surface, the cylinder head, etc., and thus HC (caused by incomplete combustion of the adhered fuel) Emissions of unburned hydrocarbons will increase. This problem can be solved by generating a desired spray pattern corresponding to various internal combustion engines to improve the ignitability of the internal combustion engine and improve the combustion performance.

An object of the present invention is to promote atomization of fuel spray and control the spray pattern (direction) without impairing atomization.

[0006]

In order to achieve the above object, there is provided a fuel injection valve having a valve seat and an injection hole at the downstream thereof and controlling fuel injection by electrically opening and closing the valve seat. A fluid passage plate located inside the reduced diameter portion of the valve member on the downstream side of the valve member having a valve seat and having an inner diameter portion for reducing the flow of the fuel fluid, and located downstream of the fluid passage plate A nozzle plate having a plurality of injection holes is provided, and the inlet side opening of the injection holes is outside the inner diameter portion of the fluid passage plate. In particular, the fuel passage plate is provided with a recess chamber which serves as a fluid chamber for forming a fuel flow for atomization, following the inner diameter portion for contracting the fuel fluid. The required flow rate required for various internal combustion engines is determined by the diameter of the inner diameter of the fuel passage plate and the height of the recess chamber, and the fuel flow suitable for atomization is formed by the height and size (diameter) of the recess chamber. To be done. The plurality of injection holes provided in the nozzle plate are configured to control at least atomization and the spray pattern, and are not designed to be a flow resistance (throttle). That is, the flow velocity is increased by the structure in which the inlet side opening of the nozzle hole of the nozzle plate is outside the inner diameter portion of the fluid passage plate, and a velocity distribution with a horseshoe-shaped cross section is generated, resulting in atomization. The fuel flow is suitable for promotion.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a vertical sectional view of an electromagnetic fuel injection valve 1 according to the present invention. The structure and operation of the fuel injection valve 1 will be described with reference to this drawing.

The fuel injection valve 1 uses the duty ON-OFF signal calculated by the control unit,
Fuel is injected by opening and closing the valve seat portion.

The magnetic circuit has a substantially cylindrical tube 2 having a fuel introduction portion at one opening end 2a and having the other opening end 2b, and an outer periphery of the cylindrical tube 2 near the opening end 2b. To the thin cylindrical member 7 of which one end is inserted and fixed to the
A tubular piece 3 having a part thereof fixed and made of a ferromagnetic material and having a function as a yoke configured to at least partially surround the electromagnetic coil 5, and a plug closing one end of the tubular piece 3. It is composed of a body portion 4 and a tubular anchor 6 that faces the open end 2b of the tubular tube 2 serving as a core with a gap.

The valve body 10 is welded to the rod 8 and the other open end of the rod 8 when a plate-shaped member having a partial opening 8a is formed by rolling on the inner peripheral surface of the anchor 6. It consists of a ball 9 that is stopped. This valve body 10 is guided by the outer peripheral portions of the anchor 6 and the ball 9, and when fuel is not injected, the valve seat portion 1 of the nozzle body 11 is guided.
It is in contact with 1a. The nozzle body 11 has a valve seat surface 11a.
Has an opening 11b having a diameter slightly smaller than the diameter thereof and is press-fitted into the inner peripheral surface 7a at one end of the thin cylindrical member 7 made of a non-magnetic material or a weak magnetic material.

A fluid passage forming plate 12 and a nozzle plate 15 are sequentially press-fitted and fixed downstream of the nozzle body 11.

When the nozzle body 11, the fluid passage forming plate 12 and the nozzle plate 15 are press-fitted and fixed, the valve body 10 has an end face of the anchor 6 of the valve body 10 and an open end 2b of the tubular tube 2 which serves as a core. The gap is adjusted. That is,
This gap is formed as the amount of axial movement of the valve element 10. Further, the valve body 10 is pressed by the return spring 17 against the valve seat surface 11a of the nozzle body 11, and the pressing force is adjusted by the axial position of the winding bush 18 formed by rolling a plate material.

Further, in the present embodiment, the lower end surface of the tubular tube 2 acting as the core serves as a stopper for receiving the anchor 6 during the valve opening operation. Therefore, the tubular tube 2
It is preferable that the lower end surface of the anchor 6 and the upper end surface of the anchor 6 are plated with chromium or the like by electrolytic plating or the like.

The coil 5 for exciting the magnetic circuit is a bobbin 19
Is wrapped around. The terminal 21 of the coil 5 is connected to the terminal of a control unit (not shown).

The outer peripheral portion of the tubular tube 2 which functions as a core and the tubular piece 3 which functions as a yoke are surrounded by a plastic molding 20 which is injection molded. In this case, the coil terminal 21 is integrally molded together. Further, an O-ring 23 for gas sealing is provided between the one end surface 20a side of the plastic molded body 20 and the bush 22 inserted and fixed to the end surface 7a of the cylindrical member 7, and the other end 20b side thereof. An O-ring 24 for fuel sealing is provided. A filter 25 is provided to prevent dust and foreign matter in the fuel from entering the so-called valve valve seat surface side between the ball 9 and the valve seat surface 11a.

The operation of the fuel injection valve 1 configured as described above will be described.

Electric ON-applied to the electromagnetic coil 5
By the OFF signal, the valve body 10 is moved up and down in the axial direction to open and close the gap between the ball 9 and the valve seat surface 11a, thereby controlling the fuel injection. When an electric signal is applied to the coil 5, a magnetic circuit is formed by the tubular tube 2 acting as a core, the tubular piece 3 having a function as a yoke, and the anchor 6, and the anchor 6 is attracted to the tubular tube 2 side. It When the anchor 6 moves, the ball 9 integrated with it also moves away from the valve seat surface 11a of the nozzle body 11, and the fuel passage is opened upstream of the fuel injection hole 16 provided in the nozzle plate. It

The fuel flows into the fuel injection valve 1 from the filter 25, passes through the internal passage of the tubular pipe 2, the inside of the anchor 6 and the opening of the rod 8 connected to the anchor 6, and reaches the valve seat surface 11a. When the valve is opened, the flow rate is adjusted or the flow is controlled by the fluid passage plate 12, and the fuel is injected to the fuel injection hole 16.

In this embodiment, the following consideration is made. (1) To improve atomization of the injected fuel, turbulence is added to the jet flow to be injected. The flow velocity of the jet stream is increased, and the turbulence is amplified by the shearing force with the outside air. Therefore, atomization of the fuel injected from the plurality of fuel injection holes 16 is promoted, and collision of jet flows with each other immediately below the injection holes is avoided. Etc. have been achieved.
A plate 12 for a fluid passage is provided as a means for achieving the above and. The fuel fluid is contracted by the inner diameter portion 13 provided in the fluid passage plate 12, and further on the downstream side, in the recessed chamber 14 provided integrally, as shown in FIG. Induce. This vortex flow is located almost upstream of the fuel injection hole 16 on the downstream side, and adds turbulence to the jet flow to be injected. Further, as shown in FIG. 4B, when the flow in the plane including the inlet of the fuel injection hole 16 is viewed (N-N direction view), it can be seen that the recess chamber 14 provided in the fluid passage plate 12 is Fuel 3 that collided
No. 1 flows into the fuel injection hole 16 again, collides with the flow flowing in from the center direction, and accelerates the jet flow. A characteristic phenomenon is that, when looking at the flow velocity distribution generated in the fuel injection hole 16, the region of the maximum flow velocity has a horseshoe shape 32 as shown by the chain double-dashed line in the figure. Further, as shown in FIG. 5, the flow velocity distribution is asymmetrical, and its maximum value is larger than that of the conventional structure. By increasing the velocity and the contact surface, the turbulence in the jet flow due to the shearing force with the outside air can be amplified, and atomization is promoted.

(2) The spray pattern is controlled by the nozzle plate 15 shown in FIG. The fuel injection holes 16 provided in the nozzle plate 15 are provided concentrically, and a spray pattern is formed so as to be symmetrical about the Y axis in the figure. In the case of the present embodiment, the injection direction is controlled in two directions, and the fuel injection holes 16a and 16b constitute one spray, and the fuel injection holes 16c and 16d in the opposite direction by 180 degrees, and another spray is injected. By configuring, a two-way spray is generated. At this time, the fuel injection hole 16 is inclined in a direction away from the center of the injection valve, and the angle θ formed by the center of the injection valve and the surface including the center of the injection hole, for example, 16a is in the range of 90 ° to 180 °. Is designed to be.

(3) The adjustment of the injection amount is performed accurately by the fluid passage plate 12 and the nozzle plate 15. That is, the accuracy is increased by the fuel injection holes 16 formed in the inner diameter portion 13 of the fluid passage plate 12 and the nozzle plate 15 being manufactured by a press punching process or the like without variation. Further, since the nozzle body 11 has the fluid passage plate 12 interposed therebetween, the nozzle plate 15 is not directly fixed by laser welding or the like as in the conventional case, and therefore is hardly affected by heat. Therefore, variations in the injection amount do not increase and deviations in the injection direction do not occur, which also has the advantage that the manufacturing yield is improved and the cost is not reduced.

Further, it is characteristic that the fluid passage plate 12 performs the following operation in order to cope with the variation in the flow rate of the fuel injection valve. Following the inner diameter portion 13 that contracts the fuel fluid, there is provided a recess chamber 14 that serves as a fluid chamber that forms a fuel flow for atomization. That is, the required flow rate required for various internal combustion engines is determined by the diameter of the inner diameter portion 13 of the fuel passage plate 12 and the height of the recess chamber 14. The height and size (diameter) of the recess chamber 14 form a fuel flow suitable for atomization. That is, the plurality of injection holes provided in the downstream nozzle plate 15 are configured to control at least atomization and the spray pattern, and are not designed to be a flow resistance (throttle). The opening of the nozzle hole of the nozzle plate 15 on the fuel inflow side (inlet side) is
A fuel flow suitable for atomization is formed by a structure that is outside the edge of the opening that forms the inner diameter portion 13 of the fluid passage plate 12 (on the side away from the valve axis).

The flow suitable for atomization means that the vortex flow generated in the recess chamber 14 is located almost upstream of the injection hole 16 and adds turbulence to the jet flow to be jetted. In addition, the recess chamber 14
That is, the fuel that has collided with has a horseshoe-shaped velocity distribution that flows into the injection hole 16 again, collides with the flow that has flowed in from the center direction, and accelerates the jet flow. Furthermore, the flow velocity distribution is asymmetrical, and its maximum value is also large. By increasing the velocity and the contact surface, the turbulence in the jet flow due to the shearing force with the outside air can be amplified, and atomization is promoted.

Next, an example of application of the fuel injection valve 1 of this embodiment to a multi-cylinder internal combustion engine will be described.

FIG. 6 is a view showing a state in which the multi-cylinder internal combustion engine is mounted on the cylinder head. FIG. 7 is a view seen from the P direction, showing the positions of the intake valve and the electromagnetic fuel injection valve 1 and the spray. It is a figure which shows the relationship of.

Reference numeral 101 denotes one of the cylinders of a multi-cylinder internal combustion engine, 102 is a combustion chamber, 103 is a piston, and 104 is a cylinder.
Is a cylinder head, 105 is an intake valve that opens and closes the intake port 106, 107 is an exhaust valve, and 108 is an exhaust pipe. 1
Reference numeral 09 is an intake passage having a central partition wall 109a separating the intake port 106 and communicating on the upstream side, 110 is an intake pipe, 111 is an intake flow control device, 112 is an intake flow, 1
Reference numeral 15 is an inner wall surface of the intake passage facing the inner wall surface 114 on the electromagnetic fuel injection valve 1 side, and 150 is a schematic view of the spray injected from the electromagnetic fuel injection valve 1. The intake flow control device 111 has an opening / closing valve 113. Two intake valves 105 are arranged side by side, and in the case of this embodiment, the spray is injected toward the intake ports 105a and 105b. Electromagnetic fuel injection valve 1
One is disposed upstream of the intake valve 105 and employs a multipoint injection (MPI) system fuel injection method.

In the present embodiment, in order to improve the quality and formation state of the air-fuel mixture in the cylinder, the electromagnetic fuel injection valve 1 having a high atomization degree of spray is attached to the cylinder head 104. Fuel does not adhere to the inner wall surfaces of the intake pipe 110 and the intake passage 109. Further, the form of the spray from the electromagnetic fuel injection valve 1 is determined by the intake passage 1 in the cylinder head 104.
The inner walls 114 and 115 of 09 have a small spread,
Adhesion to the wall surface is suppressed. Further, as shown in FIG. 7, the spray is bidirectional so as to avoid sticking to the central partition wall 109a and to be directed to the pan portions 105a and 105b of the intake valves 105 (sprays 160 and 17).
0). On the other hand, when the intake valve 105 is opened, the strong air flow 112 flowing from the intake flow control device 111
It is configured to carry 50. In this way, the directionality and shape of the spray are optimized, and the combustion chamber 10
The delay in the transportation of fuel spray to the inside of 2 is eliminated. As shown in the figure, the intake flow control device 111 narrows the passage area of the intake pipe 110 to increase the speed of the intake flow to generate a tumble flow.

When the combustion test of the internal combustion engine was carried out, the exhaust gas performance and the fuel consumption were improved, and the fuel injection valve 1 suppressed the adhesion of the fuel to the inner wall surface of the intake pipe, thereby improving the quality of the air-fuel mixture. It was confirmed that the formation and formation state were improved.

[0030]

EFFECT OF THE INVENTION By providing a fuel injection valve having a spray generation nozzle capable of simultaneously promoting the atomization of fuel and controlling the spray pattern, it is possible to purify exhaust gas and improve fuel efficiency in various internal combustion engines. You can Further, the cost of the fuel injection valve can be reduced at the same time.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a fuel injection valve.

FIG. 2 is an enlarged sectional view of an injection nozzle.

FIG. 3 is a view showing an arrangement of a plurality of injection holes of an injection nozzle.

FIG. 4 is a view showing a flow state in a fuel injection hole.

FIG. 5 is a diagram showing a flow velocity distribution at an outlet of a fuel injection hole.

FIG. 6 is a diagram showing an example of application to an internal combustion engine.

FIG. 7 is a sectional view of the internal combustion engine in the P direction.

[Explanation of Codes] 1 ... Fuel injection valve, 2 ... Cylindrical tube acting as core, 3 ... Tubular piece acting as yoke, 6 ... Anchor, 7 ... Cylindrical member, 8 ...
Rod, 9 ... Ball valve, 11a ... Valve seat surface, 12 ... Fluid control plate, 15 ... Nozzle plate, 16 ... Fuel injection hole.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromasa Kubo             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group F-term (reference) 3G066 AB02 BA03 CC15 CC24 CC26                       CD30 CE22

Claims (2)

[Claims] 1. A fuel injection valve having a valve seat and an injection hole at the downstream thereof and controlling fuel injection by electrically opening and closing the valve seat, the downstream side of a valve member having the valve seat. In the inner side of the reduced diameter portion of the valve member, the fluid passage plate having an inner diameter portion for reducing the flow of the fuel fluid, and the nozzle plate located downstream of the fluid passage plate and having a plurality of injection holes And an inlet side opening of the injection hole outside the inner diameter portion of the fluid passage plate. 2. The injection hole is inclined in a direction away from the center of the injection valve, and an angle formed by a plane including the center of the injection hole and the center of the injection valve is in the range of 90 ° to 180 °. The fuel injection valve according to claim 1.