JP2002295330A - Magnetostrictive fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetostrictive fuel injection valve surely preventing corrosion of an electromagnetic coil by a corrosive material within fuel and usable for a long time. SOLUTION: This magnetostrictive fuel injection valve is composed of a cylindrical casing 1 in which the inside is a fuel passage 11, an injection nozzle 3 is fit to one end, and a fuel induction pipe is connected to the other end; a magnetostrictive element pipe 4 coaxially inserted into the casing 1, working one end as a lower end (a locking end) 41 and the other end as a upper end (a free end) 42; a rod 5 coaxially inserted into the magnetostrictive element pipe 4, connecting one end to a needle 6 arranged inside the injection nozzle 3, locking the other end in the free end 42 of the magnetostrictive element pipe 4; and an electromagnetic coil 7 applying a magnetic field to the magnetostrictive element pipe 4 installed in the outer circumference of the casing 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection valve using a magnetostrictive element tube and an electromagnetic coil.

[0002]

2. Description of the Related Art As a fuel injection valve of a direct injection gasoline engine (direct injection engine) into a cylinder, a rod-shaped giant magnetostrictive element is arranged in an electromagnetic coil and a needle (valve element) is connected to the giant magnetostrictive element. In addition, a magnetostrictive fuel injection valve that opens and closes an injection hole of an injection nozzle by applying a magnetic field to the giant magnetostrictive element by energizing an electromagnetic coil to open and close the injection hole has been studied (Japanese Patent Application Laid-open No. Hei 4 (1994)).
-81565 gazette). Also, Japanese Patent Application Laid-Open No. 9-310654
Japanese Patent Application Laid-Open Publication No. H11-163873 proposes a magnetostrictive fuel injection valve in which a rod-shaped valve body is disposed in a giant magnetostrictive element tube to enable an injection hole to open inward, thereby preventing the adverse effect of deposit.

[0003]

In a conventional magnetostrictive fuel injection valve, since an electromagnetic coil is accommodated in a casing of the magnetostriction fuel injection valve in which a fuel flow path is incorporated, a small amount of fuel mixed in the fuel is used. This causes a problem that corrosive substances such as moisture infiltrate into the electromagnetic coil. For this reason, there is a defect that the electromagnetic coil is corroded with time, cannot withstand long-term use, and has low practicality. An object of the present invention is to provide a magnetostrictive fuel injection valve which can reliably prevent a corrosive substance in fuel from corroding an electromagnetic coil and can be used for a long time.

[0004]

SUMMARY OF THE INVENTION A magnetostrictive fuel injection valve for an internal combustion engine according to the present invention has a fuel passage inside, a fuel injection pipe attached to one end, and a fuel introduction pipe connected to the other end. -Shaped casing, a magnetostrictive element tube coaxially inserted into the casing, one end of which is a locking end, and the other end of which is a free end; and a coaxially inserted and inserted into the magnetostrictive element tube. One end is connected to a valve body disposed in the spray nozzle, and the other end is fixed to a free end of the magnetostrictive element tube, and a magnetic field is applied to the magnetostrictive element tube installed on the outer periphery of the casing. And an electromagnetic coil.

[0005]

According to the present invention, an electromagnetic coil for applying a magnetic field to the magnetostrictive element is provided on the outer periphery of the cylindrical casing outside the fuel passage. Therefore, it is possible to prevent the corrosive substance in the fuel from corroding the electromagnetic coil, thereby enabling long-term use. In this case, in order to efficiently apply the magnetic field of the electromagnetic coil to the magnetostrictive element, it is desirable to use a non-magnetic material such as a stainless steel pipe for the casing.

According to a second aspect of the present invention, a movable bush is connected to a free end of the magnetostrictive element tube, and a flange is provided at the other end of the rod to engage with an end surface of the movable bush. For one end. With this configuration, the inner opening of the valve port of the injection nozzle can be easily realized,
As in the case of the outward opening, it is possible to reliably prevent a problem that the deposit adheres to the valve body and the injection rate becomes inaccurate.

According to a third aspect of the present invention, a fuel passage is provided inside the fuel introduction pipe, and an adjusting (adjusting) pipe for adjusting the urging force of the spring is screwed into the fuel introduction pipe. By turning the adjustment pipe, adjustment of the spring load can be easily performed. Therefore, the opening and closing times of the valves can be made uniform with a simple operation, and the injection rate can be accurately adjusted. In addition, it is desirable to provide a rotation preventing means for the adjustment pipe by vibration.

According to the fourth aspect of the present invention, since the thermal expansion of the magnetostrictive element and the rod is approximated, it is possible to accurately compensate for a temperature change due to a rise in fuel temperature or the like with a simple configuration. . For this reason, it is possible to perform appropriate injection rate control according to a wide range of operating conditions.

[0009]

FIG. 1 shows a magnetostrictive fuel injection valve 10 of a direct injection gasoline engine according to the present invention, which is provided with a cylindrical casing 1 having a fuel passage 11 inside. A fuel introduction pipe 2 is connected to an upper end of the casing 1, and an injection nozzle 3 is attached to a lower end. The fuel introduction pipe 2 is connected to a high-pressure fuel supply source such as a common rail, and the injection nozzle 3 injects fuel into a cylinder of the engine.

The casing 1 is made of a nonmagnetic metal, has an inner peripheral edge 12 at the lower end, and has a cylindrical magnetostrictive element tube 4 inserted therein. The magnetostrictive element tube 4 has a lower end 41 fixed to the inner peripheral edge 12 and an upper end 42 as a free end.
It can be extended upward. The lower end of the fuel introduction tube 2 is screwed into the casing 1, and a gap 22 is provided between the lower end surface 21 of the fuel introduction tube 2 and the upper end surface 43 of the magnetostrictive element tube 4.
Is provided.

A movable bush 45 is provided in the gap 22 in contact with the upper end 42 of the magnetostrictive element tube 4, and an outer portion of the upper surface of the movable bush 45 and a lower end surface 21 of the fuel introduction pipe 2 are provided.
And a disc spring 44 is interposed therebetween. In the magnetostrictive element tube 4, the rod 5 is disposed so that the upper end thereof is positioned on the movable bush 45 and is coaxially inserted therethrough. The linear expansion of the rod 5 matches the linear expansion of the magnetostrictive element tube 4, and the elongation of the magnetostrictive element tube 4 due to the temperature rise of the fuel is offset by the elongation of the rod 5.

The movable bush 45 is provided with a slit 46 for securing a fuel passage between the movable bush 45 and the outer periphery of the upper end of the rod 5. A flange 52 having a fuel passage hole 51 is provided at the upper end of the rod 5, and the flange 52 is engaged with the inside of the upper surface of the movable bush 43, and a rod body 53 is provided.
Has a lower end extending into the injection nozzle 3 through the inside of the movable bush 45 and the center of the magnetostrictive element tube 4.

An adjusting pipe 23 having a fuel passage therein is screwed into the fuel introducing pipe 2.
A spring 24 is interposed between the flange 3 and the flange 52 to press the rod 5 downward (to close the valve). By rotating the adjustment pipe 23, the spring load of the spring 24 can be adjusted, and the acting force required for opening the valve can be increased or decreased. As a result, the valve opening time can be adjusted accurately, which is effective for proper control of the injection rate.

The injection nozzle 3 has a cylindrical valve body 31 externally fitted to the lower end of the casing 1 and a ferromagnetic nozzle body 3 fitted to the lower end of the valve body 31.
2 is provided. The rod body 5 is provided in the nozzle body 32.
A needle 6 serving as a valve body connected to the lower end 54 of 3 is inserted. The injection hole 33 is provided at the tip of the nozzle body 32.
Is opened, and a sheet surface 34 is provided on the inner periphery.

The upper end of the needle 6 has a large diameter portion 6 with a recess 61.
The lower end 54 of the rod body 53 is fitted. A lower portion of the needle 6 is provided with a flange 63 having substantially the same diameter as the large-diameter portion 62.
4 is open. The flange 63 is slidable on the inner periphery of the nozzle body 32 and has an action of holding the needle 6 at the center position.

An electromagnetic coil 7 for applying a magnetic field to the magnetostrictive element tube 4 is externally fitted on the outer periphery of the casing 1, and is surrounded by a ferromagnetic outer tube 71. In this embodiment, the electromagnetic coil 7 includes a bobbin 72 externally fitted to the casing 1 and a conductive wire 73 wound around the bobbin 72. In addition, it is a matter of course that the covered conductor may be directly wound around the outer periphery of the casing 1 to form the electromagnetic coil.

According to the present invention, the control circuit 8 controls the electromagnetic coil 7
, A magnetic field is applied to the magnetostrictive element tube 4, the magnetostrictive element tube 4 expands, and the upper end 42, which is a free end, is displaced upward. As a result, the movable bush 45 compresses the disc spring 44 and is displaced upward, and the rod 5 moves upward via the flange 52 engaged with the movable bush 45. As a result,
The needle 6 connected to the rod 5 moves upward, the injection hole 33 opens inward, and fuel is injected.

According to the structure of this embodiment, the electromagnetic coil 7
However, since it is disposed outside the casing (outside the fuel passage), it can be reliably prevented from being corroded by corrosive liquids such as water contained in the fuel, and has excellent durability and can be used for a long time. A magnetostrictive fuel injection valve can be manufactured. Further, it is possible to effectively prevent a change in the injection rate due to a fuel temperature rise or a deposit, and it is easy to adjust the injection rate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection valve of an internal combustion engine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 10 Magnetostrictive fuel injection valve 11 Fuel passage 2 Fuel introduction pipe 23 Adjustment pipe (adjusting) 24 Spring 3 Injection nozzle 4 Magnetostrictive element pipe 41 Lower end (locking end) 42 Upper end (free end) 45 Movable bush 5 Rod 6 Needle (valve element) 63 Flange 7 Electromagnetic coil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 41/12 H01L 41/12 F-term (Reference) 3G066 AA02 AB02 AD12 BA32 BA50 CC01 CC06U CC14 CC53 CE27

Claims (4)

[Claims] 1. A cylindrical casing having a fuel passage inside, an injection nozzle attached to one end, and a fuel introduction pipe connected to the other end; and a coaxially inserted casing. One end is a locking end, the other end is a free end, and a magnetostrictive element tube is coaxially inserted into the magnetostrictive element tube, and one end is connected to a valve body disposed in the injection nozzle, A magnetostrictive fuel injection valve comprising: a rod having the other end locked to a free end of the magnetostrictive element tube; and an electromagnetic coil installed on an outer periphery of the casing and applying a magnetic field to the magnetostrictive element tube. 2. The magnetostrictive fuel injection valve according to claim 1, wherein a movable bush is connected to a free end of the magnetostrictive element tube, and a flange engaged with an end face of the movable bush is connected to the other end of the rod. Wherein the collar is urged in one direction by a spring. 3. The magnetostrictive fuel injection valve according to claim 2, wherein an adjusting pipe for adjusting a biasing force of the spring is screwed into the fuel introduction pipe. 4. The magnetostrictive fuel injection valve according to claim 1, wherein a linear thermal expansion of the rod is approximated to a linear thermal expansion of the magnetostrictive element tube. Injection valve.