JPH0742865U - Electromagnetic fuel injection valve - Google Patents

Abstract

(57) [Abstract] [Purpose] A means for absorbing pressure pulsation is manufactured at a low cost to suppress an increase in the manufacturing cost of a fuel injection valve. [Structure] An annular recess is formed on the outer periphery of the valve seat 6,
The tubular diaphragm 11 is arranged on the annular recess 6D.
The fuel chamber 14 is formed by the inner side of the diaphragm 11 and the annular recess 6D, and the outer side of the diaphragm 11 and the housing 1
The elastic member storage chamber 15 is formed by and. The lower portion of the fuel chamber 14 is communicated with the needle valve guide hole 6E below the guide portion 7B of the needle valve 7, and the upper portion of the fuel chamber 14 is above the guide portion 7B of the needle valve 7 6G.
Is communicated with. An O-ring 16 is provided in the elastic member storage chamber 15.
And the O-ring 16 is brought into contact with the diaphragm 11.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic fuel injection valve (hereinafter referred to as a fuel injection valve) used in a fuel injection device for an internal combustion engine of an automobile or the like, and in particular, a means for absorbing pressure pulsation generated when a needle valve opens and closes is provided. A fuel injection valve provided.

[0002]

[Prior art]

 In the fuel injection valve, when the valve part of the needle valve opens the valve seat of the valve seat by energizing the electromagnetic coil, the fuel pressure upstream from the valve part of the needle valve drops once and then rises and falls repeatedly. When the pressure converges to a predetermined pressure and the electromagnetic coil is de-energized and the valve portion of the needle valve closes the valve seat, the pressure rises and then pulsating pressure is generated.

As described above, when the above-mentioned pulsating pressure is generated during the opening / closing operation of the fuel injection valve, the linearity of the injection amount with respect to the pulse width applied to the electromagnetic coil becomes poor, and stable control of the injection amount becomes difficult. In addition, variations in the injection amount occur and the reproducibility of the injection characteristics is reduced, which is not preferable.

A technique for absorbing pulsating pressure in such a fuel injection valve is disclosed in Japanese Patent Laid-Open No. 4-1464. This is a device in which a pressure damper means that seals pressurized gas is arranged near the valve body, and the pressurized gas expands and contracts in response to the pressure pulsation that accompanies the opening / closing operation of the valve body. It absorbs pulsation.

[0005]

[Problems to be solved by the device]

 According to such a conventional fuel injection valve, the pressure damper means is formed by sealing the pressurized gas. Therefore, (1) it is necessary to prepare the pressurized gas. (2) Since it is necessary to store the pressurized gas in the member and then to seal the pressurized gas so as to maintain a constant pressure, the manufacture of the pressure damper means becomes expensive, and the fuel injection valve cannot be provided inexpensively. It has the disadvantage of

[0006]

[The purpose of the device]

 The fuel injection valve according to the present invention has been made in view of the above problems, and an object of the invention is to manufacture a means for absorbing pressure pulsation at a low cost and suppress an increase in the manufacturing cost of the fuel injection valve.

[0007]

[Means for solving the problem]

 The above-mentioned problem is formed in the valve seat arranged at the end of the housing by the valve portion of the needle valve that is driven integrally with the movable core by driving the movable core by energizing the electromagnetic coil arranged inside the housing. In an electromagnetic fuel injection valve that controls the opening and closing of the valve seat and injects fuel from the injection hole on the downstream side of the valve seat, an annular recess is formed in the outer periphery of the valve seat, and the opening of the annular recess is made cylindrical. It is surrounded and closed by a diaphragm, and a fuel chamber is formed by the inside of the diaphragm and the annular recess and an elastic member storage chamber is formed outside the diaphragm, and the lower part of the fuel chamber is located below the guide part of the needle valve. It is opened in the needle valve guide hole, the upper part of the fuel chamber is opened in the needle valve guide hole above the guide part, and the elastic member storage chamber is made of a rubber material. This is achieved by placing an O-ring.

[0008]

[Action]

 When a pulsating pressure is generated in the needle valve guide hole where the valve seat is formed as the needle valve opens and closes, this pressure acts in the fuel chamber and causes the diaphragm to reciprocate to repeatedly compress the O-ring. The pulsating pressure is absorbed by this. Thus, the linearity of the injection amount, the stability control, and the variation of the injection amount can be improved.

[0009]

【Example】

 An embodiment of the fuel injection valve according to the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a cylindrical housing having an opening in the vertical direction. An electromagnetic coil 3 wound around a coil bobbin 2 and a fixed core 4 are inserted from the upper end of the housing, and an enlarged flange portion 4A of the fixed core 4 is inserted. The upper end of the housing 1 is crimped inward toward the upper end of the enlarged flange 4A in a state where the housing 1 is arranged on the locking step 1A. The electromagnetic coil 3 is drawn out through the terminal 5, a flow path 4B is bored from the upper end to the lower end in the center of the fixed core 4, and an opening above the flow path 4B is provided in a fuel pump (not shown). An electrical signal is input to the electromagnetic coil 3 via the terminal 5 in communication with the discharge hole.

The valve seat 6 inserted into the housing 1 through the lower opening of the housing 1 has the following configuration. Reference numeral 6A denotes a tapered valve seat formed below, and a needle valve guide hole 6B opens upward from the valve seat 6A, and an upper portion of the needle valve guide hole 6B is an upper end of the valve seat 6. Is formed so as to open toward. Further, an injection hole 6C is opened from below the valve seat 6A toward the lower end surface of the valve seat 6.

A needle valve 7 is movably arranged in the needle valve guide hole 6B and has the following configuration. 7A is a valve portion that is formed at the tip of the needle valve 7 and that opens and closes the valve seat 6A. A guide portion 7B is formed above the valve portion 7A. It has the same shape as the cross section of the hole 6B and a plurality of cutout surfaces 7C are formed. That is, the fuel passage formed in the guide portion 7B in the needle valve guide hole 6B is formed by the gap formed by the inner peripheral surface of the needle valve guide hole 6B and the cutout surface 7C. Two guide portions 7B in the present embodiment are formed in the vertical direction. A movable core 8 facing the lower end of the fixed core 4 is integrally arranged at the upper end of the needle valve 7, and a spring 9 is contracted between the lower end of the fixed core 4 and the upper end of the movable core 8. It was That is, the needle valve 7 is pressed downward by this spring 9, and the valve portion 7A contacts the valve seat 6A.

An annular recess 6D is formed in the outer periphery of the valve seat 6, and the annular recess 6D opens in a ring shape on the outer periphery of the valve seat 6. The lower portion of the annular recess 6D is communicated with the needle valve guide hole 6E located below the lower guide portion 7B by the first passage 6F, and the upper portion of the annular recess 6D is located above the lower guide portion 7B. It is communicated with the needle valve guide hole 6G in the second passage 6H.

Then, the valve seat 6 is assembled to the housing 1 as follows. A valve seat 6 having a stopper 10 and a needle valve 7 is arranged on a locking step portion 1B formed below the housing 1. On the other hand, the tubular diaphragm 11 is disposed so as to surround the annular recess 6D that is open to the outer periphery of the valve seat 6, and thereafter, the annular diaphragm above the tubular diaphragm 11 is located inside the housing 1. The first ring member 12 is arranged on the outer peripheral end, and the second ring member 13 is arranged on the lower annular outer peripheral end of the cylindrical diaphragm 11, and in this state, the lower open end of the housing 1 is closed. The lower tip of the seat 6 is swaged inward toward the top. (The first ring member 12 and the second ring member 13 have a vertical gap.) As described above, the annular opening of the annular recess 6D formed in the valve seat 6 is formed by being closed by the diaphragm 11. According to this, a sealed fuel chamber 14 is formed by the inside of the diaphragm 11 and the annular recess 6D, and the lower portion of this fuel chamber 14 is below the guide portion 7B by the first passage 6F. The fuel chamber 14 is communicated with the guide hole 6E, and the upper portion of the fuel chamber 14 is communicated with the needle valve guide hole 6G above the guide portion 7B by the second passage 6H.

On the other hand, an elastic member storage chamber 15 is formed between the outside of the diaphragm 11 and the inside of the housing 1, and an O ring 16 is arranged in the elastic member storage chamber 15 and the O ring 16 is It contacts the outside of the diaphragm 11.

Next, the operation will be described. When a drive pulse is applied to the electromagnetic coil 3, the needle valve 7 reciprocates, the valve portion 7A opens and closes the valve seat 6A, the controlled fuel is injected from the injection hole 6C, and the valve portion 6A releases the valve seat 6A. When the valve is opened, the fuel pressure in the needle valve guide hole 6B as a fuel passage on the upstream side of the valve seat 6A once drops and then rises and falls repeatedly until it converges to a constant pressure. When the valve 6A is closed, the fuel pressure once rises and then rises and falls repeatedly. As a result, pulsating pressure is generated in the needle valve guide hole 6B. On the other hand, in the fuel injection valve of the present invention, since the fuel chamber 14 is always communicated with the needle valve guide hole 6B by the first passage 6F and the second passage 6H, the fuel is always kept in the fuel chamber 14. When the pulsating pressure is generated in the needle valve guide hole 6B as the valve seat 6A is opened and closed, this pulsating pressure is immediately introduced into the fuel chamber 14. According to the above, when the pressure in the fuel chamber 14 rises, the diaphragm 11 moves to the elastic member storage chamber 15 side and presses the O-ring 16 to cause contraction deformation, which alleviates the rising pressure. On the other hand, when the pressure in the fuel chamber 14 drops, the O-ring 16 expands and deforms (the pressure is released to restore the original shape) to press and deform the diaphragm 11 toward the fuel chamber 14. As a result, the reduced pressure is alleviated, and when the pulsating pressure is generated, the above-mentioned operation is repeated, so that the needle valve guide hole 6B near the valve seat 6A of the valve seat 6 (in other words, the needle valve below the guide portion 7B). The pulsating pressure in the guide hole 6E) can be effectively absorbed, and thus the amplitude of the pulsating pressure and the convergence time can be shortened.

Further, the fact that the first passage 6F is opened in the needle valve guide hole 6E below the guide portion 7B below the needle valve 7 is located near the valve seat 6A of the valve seat 6 where pulsating pressure is generated. Since the fuel chamber 14 is connected, the pulsating pressure can be introduced into the fuel chamber 14 without time delay, and the pulsating pressure can be effectively reduced.

In addition, the opening of the first passage 6F and the second passage 6H in the fuel chamber 14 can prevent the accumulation of air in the fuel chamber 14 and reduce the damper effect due to air compression. The pulsation pressure was able to be damped favorably without the pulsation pressure.

Further, according to the present invention, the fuel chamber 14 for damping the pulsating pressure is provided with an annular recess 6D formed in the outer periphery of the valve seat 6 and a diaphragm for surrounding and closing the opening of the annular recess 6D. 11 and the elastic member storage chamber 15 is formed by the diaphragm 11 and the housing 1, and the O-ring 16 may be arranged in the elastic member storage chamber 15 so that the manufacturing thereof is extremely easy. Therefore, it does not increase the manufacturing cost of fuel injection valves.

[0019]

[Effect of device]

 As described above, according to the fuel injection valve of the present invention, since the damper can be arranged in the fuel injection valve with the extremely simple structure, the manufacturing cost is low, the injection amount is linear, and the stability and reproducibility are improved. It is possible to provide an excellent fuel injection valve.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an electromagnetic fuel injection valve of the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part of a valve seat portion of FIG.

[Explanation of symbols]

 1 Housing 3 Electromagnetic Coil 6 Valve Seat 6A Valve Seat 6C Injection Hole 6D Annular Recess 6E Needle Valve Guide Hole Below Guide 7B 6G Needle Valve Guide Hole Above Guide 7B 7 Needle Valve 7A Valve 7B Guide 11 Diaphragm 14 Fuel chamber 15 Elastic member storage chamber 16 O-ring

Claims (1)

[Scope of utility model registration request] 1. A movable core 8 is driven by energizing an electromagnetic coil 3 disposed inside the housing 1, and a valve portion 7A of a needle valve 7 that is integrally driven with the movable core 8 causes an end portion of the housing 1 to move. In an electromagnetic fuel injection valve that controls opening / closing of a valve seat 6A formed on a valve seat 6 arranged and injects fuel from an injection hole 6C on the downstream side of the valve seat 6A, an annular recess 6D is formed on the outer periphery of the valve seat 6. And the opening of the annular recess 6D is surrounded and closed by the cylindrical diaphragm 11, the fuel chamber 14 is formed by the inside of the diaphragm 11 and the annular recess 6D, and the elastic member accommodating chamber is provided outside the diaphragm 11. 15 is formed, the lower side of the fuel chamber is opened in the needle valve guide hole 6E below the guide portion 7B of the needle valve 7, and the upper side of the fuel chamber 14 is formed in the guide portion 7B. An electromagnetic fuel injection valve having an O-ring 16 made of a rubber material, which is opened in the needle valve guide hole 6G at a higher position and is further arranged in the elastic member storage chamber 15.