JPH06621Y2 - Electromagnetic fuel injection valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electromagnetic fuel injection valve used in an electronically controlled fuel injection internal combustion engine or the like.

<Prior Art> In an electronically controlled fuel injection internal combustion engine, an intake air obtained by a control device based on a signal (for example, a voltage) output from an intake air flow rate detection device (air flow meter) corresponding to an intake air flow rate. From the air flow rate Q and the engine speed N calculated from the crank angle sensor, the ignition signal from the ignition coil, etc., the basic fuel injection width T _p (= K ×
Q / N; K is a constant) is calculated.

Further, after calculating various correction coefficients according to the engine operating state such as the engine cooling water temperature and the correction amount T _s by the battery voltage, the fuel injection width T _i (= T _p × various correction coefficients × α + T _s )
Is calculated.

Here, α is an air-fuel ratio feedback correction coefficient.

Then, based on the reference signal obtained from the crank angle sensor, the electromagnetic fuel injection valve is driven to open with the injection pulse width of the fuel injection width T _i in synchronism with the rotation of the engine to perform fuel injection.

Conventionally, as an electromagnetic fuel injection valve in such an electronically controlled fuel injection type internal combustion engine, for example, there is one shown in FIG. 4 (see Japanese Utility Model Laid-Open No. 62-116164, etc.).

That is, the nozzle member 3 is provided at the tip of the housing 1 via the holder 2. A nozzle hole member 4 forming a nozzle hole 4a is provided at the tip of the nozzle member 3,
A valve seat 5 is provided at the rear end portion.

A convex hemispherical valve element 6 is provided on the valve seat 5 side of the nozzle member 3.
Are opposed to each other, and a flat movable element 7 is provided on the back side of the valve element 6.
Is fixed.

A cylindrical core 8 is provided at the center of the housing 1, and an end surface of the core 8 faces the flat movable element 7. A coil spring 10 is interposed between the valve body 6 and the end surface of the adjusting rod 9 inserted through the center hole 8a of the core 8, and the elastic force of the coil spring 10 causes the valve body 6 to move to the valve seat 5 The seat is biased in the seating direction.

Reference numeral 11 is a leaf spring for centering the valve body 6.

On the other hand, a resin coil bobbin 12 is provided on the outer circumference of the core 8, and an electromagnetic coil 13 is wound around the outer circumference of the coil bobbin 12. The coil bobbin 12 is integrally formed with a terminal holding portion 14 projecting therefrom. The terminal holding portion 14 holds a terminal 15 connected to the electromagnetic coil 13, and the terminal 15 is projected to the outside of the housing 1. .

In such a configuration, the fuel supplied from the fuel inlet 16 formed in the peripheral wall of the housing 1 is introduced into the housing 1 and stored in the high pressure chamber 17 around the valve body 6. And
The valve body 6 is attracted upward together with the flat movable element 7 by the electromagnetic attraction force generated in the core 8 by the electromagnetic coil 13.
When the valve is separated from the valve seat 5, the fuel in the high pressure chamber 17 is injected from the injection hole 4a.

Here, in order to adjust the dynamic fuel injection amount (flow rate per lift of the valve body 6), the adjusting rod 9 is moved in the axial direction to adjust the set pressure of the coil spring 10 to lift the valve body 6. Adjust the amount.

<Problems to be Solved by the Invention> However, in such a conventional electromagnetic fuel injection valve, a core 8 is formed in a cylindrical shape and a dynamic fuel injection amount is adjusted in a center hole 8a thereof. Since the adjustment rod 9 is inserted and arranged, the outer diameter of the core 8 is increased, and the external shape of the fuel injection valve itself is inevitably increased.

When the fuel injection valve becomes large in this way, for example, the mounting position on the engine of the multipoint injection (MPI) system is restricted, and in particular, the port shape becomes thin and long due to the recent multiplicity of intake valves. In the configuration, the fuel injection valve is moved away from the intake valve, which causes a problem that a fuel response delay occurs during a transition.

Further, as a result of increasing the distance between the fuel injection valve and the intake valve, there is a drawback that the injection angle becomes smaller and the spray particle size becomes larger.

In view of the above conventional problems, the present invention aims to reduce the size of the core by improving the core and the dynamic fuel injection amount adjusting structure, thereby reducing the outer shape of the fuel injection valve itself. To aim.

<Means for Solving the Problems> For this reason, the electromagnetic fuel injection valve of the present invention has a nozzle portion provided at the front end of the housing, having a nozzle hole at the front end and a valve seat at the base end, and A valve body made of a magnetic material, which is arranged to face the valve seat, a core made of a solid member whose tip portion faces the valve body, and which is arranged at the center of the housing. An electromagnetic coil is provided, and the core is supported in a housing so that the core can be moved forward and backward in the axial direction and can be fixed at an arbitrary forward and backward position, and a gap between the valve body and the core can be adjusted.

<Operation> With this configuration, when the electromagnetic coil is not energized, the valve body
Due to the pressure difference of the fuel acting between the surface on the valve seat side and the surface on the opposite side, the valve seats on the valve seat and is held closed. Then, when the electromagnetic coil is energized and excited, the valve body is attracted to the core and separated from the valve seat, and when the valve is opened, the fuel flows out from the gap between the valve body and the valve seat, and fuel injection is performed. Be seen.

In such a configuration, it is not necessary to adopt a configuration in which the core is formed into a cylindrical shape and the adjustment rod is inserted, and by configuring the core with a solid member, the outer diameter dimension of the core can be reduced, and the outer shape of the fuel injection valve itself. Can be miniaturized.

The dynamic fuel injection amount is adjusted by moving the core forward and backward in the axial direction and adjusting the clearance between the valve body and the core to adjust the lift amount of the valve body.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a cylindrical yoke 20 as a housing
A nozzle member 22 is provided at the tip of the nozzle via a holder 21. An orifice tip 23 as a nozzle hole member that forms a metering orifice 23a as a nozzle hole is provided at the tip of the nozzle member 22, and a valve seat 24 is provided at the rear end.

On the valve seat 24 side of the nozzle member 22, a convex hemispherical valve body 25 formed by dividing a hollow sphere into two is arranged oppositely, and on the back surface side of the valve body 25 is a flat-shaped one. The leaf spring 26 is fixed.

A plurality of communication holes 26 are provided around the valve body 25 of the leaf spring 26.
a is formed.

The leaf spring 26 is clamped and fixed by a pair of ring-shaped restraining members 27 and 28 arranged on the inner peripheral portion of the holder 21.

In this case, the lift amount of the valve body 25 and the set load of the leaf spring 26 are determined by the fixing position and the fixing portion of the leaf spring 26 by the pair of ring-shaped restraining members 27 and 28.

A rod-shaped core 29 made of a solid member is provided in the center of the yoke 20, and an end surface of the core 29 faces the leaf spring 26.

On the other hand, an electromagnetic coil 30 is wound around the outer periphery of the core 29. A terminal holding portion 29a is integrally formed with the core 29, and a terminal 31 connected to the electromagnetic coil 30 is held in the terminal holding portion 29a, and the terminal 31 is fixed to the outer periphery of the rear end of the yoke 20 by caulking or the like. It is projected to the outside of the yoke 20 via the socket 32.

A fuel inlet 33 for introducing fuel into the yoke 20 and a fuel outlet 34 for returning surplus fuel to a tank (not shown) via a fuel pressure regulator (not shown) are provided on the peripheral wall of the yoke 20.

The outer peripheral surface of the terminal holding portion 29a of the core 29 and the yoke 20
The inner peripheral surface of the rear end portion is screw-fitted, and the core 29 is held by the yoke 20 so that the core 29 can move forward and backward in the axial direction and can be fixed at an arbitrary forward and backward position. 36 has an adjustable structure.

Next, the operation of this configuration will be described.

Fuel is introduced into the yoke 20 from the fuel inlet 33, and through the communication hole 26a of the leaf spring 26, the high pressure chamber 3 around the valve body 25.
It is stored in 5. Here, when the electromagnetic coil 30 is energized, the valve body 25 is attracted upward together with the leaf spring 26 by the electromagnetic attraction force generated in the core 29, and the valve seat 2
4, the fuel in the high pressure chamber 35 is ejected from the metering orifice 23a.

When the electromagnetic coil 30 is not energized, the valve body 25 is applied to the valve seat 24 by the pressure difference of the fuel acting between the surface on the valve seat 24 side and the surface on the opposite side thereof and the elastic biasing force of the leaf spring 26. It is seated and kept closed.

Here, the adjustment of the fuel injection amount will be described. The fully opened flow rate of the valve body 25, that is, the static fuel injection amount is measured when the valve body 25 is in the full lift state, and the orifice tip 2
The flow rate is set by changing the diameter of the metering orifice 23a provided in No. 3.

In addition, the intermittent injection amount when a constant pulse is applied, that is, the dynamic fuel injection amount, causes the core 29 to move forward and backward in the axial direction to cause the leaf spring 2 to move.
This is performed by adjusting the gap 36 between the core 6 and the core 29 and adjusting the lift amount of the valve body 25.

After initializing the injection amount in this way, the socket 3
2 is fixed to the rear end of the yoke 20 by caulking or the like, and the core 2
Prevent rotation of 9.

According to this structure, by forming the core 29 with a solid member, the outer diameter of the core 29 can be downsized, and the outer shape of the fuel injection valve itself can be downsized. Further, since the gap between the leaf spring 26 and the core 29 can be adjusted by moving the core 29 in the axial direction, the dynamic fuel injection amount can be easily and reliably adjusted by adjusting the lift amount of the valve body 25. You can do it.

2 and 3 show the intake port 3 of the MPI type engine of the conventional fuel injection valve 37 and the fuel injection valve 38 of the present invention, respectively.
9 is a diagram specifically showing the state of attachment to the 9th section. In the conventional fuel injection valve 37, as shown in FIG. 2, the distance between the fuel injection valve 37 and the intake valve 40 is about 100 mm, and the injection inclination angle is 33 °
Therefore, the injection angle must be 10 ° in order to prevent fuel from adhering to the wall surface of the intake port 39.

On the other hand, in the fuel injection valve 38 of the present invention, as a result of downsizing as described above, as shown in FIG.
It is possible to make the distance between the intake valve 40 and the intake valve 40 close to 90 mm, the injection inclination angle is 35 °, the injection angle can be increased to 14 °, and the atomization particle size of the fuel can be made fine. Moreover, it is clear that a large space is not required at the mounting position of the fuel injection valve 38.

In the present embodiment, the leaf spring 26 is provided and the valve body 25
However, the leaf spring 26 need not be provided. In this case, when the electromagnetic coil 30 is not energized,
The valve body 25 is held closed by only the pressure difference of the fuel acting between the surface on the valve seat 24 side and the surface on the opposite side.

Further, when the plate spring 26 is removed in this way, a means for restricting the position of the valve body 25 is provided so that the valve body 25
It is desirable to perform the positioning.

<Effects of the Invention> As described above, according to the electromagnetic fuel injection valve of the present invention, the core disposed at the center of the housing with the tip end facing the valve body is made of a solid member. By moving the valve back and forth in the axial direction, the gap between the valve element and the core can be adjusted to adjust the dynamic fuel injection amount, so the core is made cylindrical and the dynamic fuel injection amount adjusting rod is inserted. It is possible to reduce the outer diameter of the core and to reduce the outer shape of the fuel injection valve by configuring the core with a solid member without adopting the above configuration.

As a result, it is possible to mount the fuel injection valve at an ideal position in a multipoint injection (MPI) type internal combustion engine without being restricted by the mounting position of the fuel injection valve. This is a great practical effect that has the advantage that the particle size can be made fine.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of an electromagnetic fuel injection valve according to the present invention, and FIGS. 2 and 3 show the mounting states of the conventional and present electromagnetic fuel injection valves to an engine. Longitudinal section,
FIG. 4 is a longitudinal sectional view showing an example of a conventional electromagnetic fuel injection valve. 20 ... Yoke 22 ... Nozzle member 23 ... Orifice tip 23a ... Metering orifice 24
... Valve seat 25 ... Valve element 29 ... Core 30 ... Electromagnetic coil 36 ... Gap 38 ... Fuel injection valve

Claims (1)

[Scope of utility model registration request] 1. A nozzle portion provided at a tip end portion of a housing, a nozzle hole provided at a tip end portion of the housing, and a valve seat at a base end portion of the housing, and a valve element made of a magnetic material and arranged to face the valve seat. A core formed of a solid member is disposed in the center of the housing with its tip end facing the valve body, and an electromagnetic coil disposed on the outer periphery of the core. The core can be moved forward and backward in the axial direction. In addition, the electromagnetic fuel injection valve is characterized in that it is supported by a housing so that it can be fixed at any advancing / retreating position, and the gap between the valve element and the core can be adjusted.