JP4254073B2 - Magnetostrictive fuel injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection valve using a magnetostrictive element tube and an electromagnetic coil.
[0002]
[Prior art]
As a fuel injection valve of a direct injection gasoline engine (direct injection engine) into a cylinder, a rod-shaped super magnetostrictive element is arranged in the electromagnetic coil, and a needle (valve element) is connected to the super magnetostrictive element, to the electromagnetic coil. 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 expanding and contracting it has been studied (Japanese Patent Laid-Open No. 4-81565). Japanese Patent Application Laid-Open No. 9-310654 proposes a magnetostrictive fuel injection valve in which a rod-shaped valve element is arranged in a giant magnetostrictive element tube so that the injection hole can be opened, thereby preventing the harmful effects of deposit. .
[0003]
[Problems to be solved by the invention]
The conventional magnetostrictive fuel injection valve has an electromagnetic coil housed in the casing of the magnetostrictive fuel injection valve in which a fuel flow path is incorporated, so that corrosive substances such as a minute amount of moisture mixed in the fuel are electromagnetic coil. Problems that penetrate into For this reason, the electromagnetic coil corrodes with time, and there exists a fault which cannot endure long-term use and has low practicality.
An object of the present invention is to provide a magnetostrictive fuel injection valve that can reliably prevent a problem that a corrosive substance in fuel corrodes an electromagnetic coil and can be used for a long time.
[0004]
[Means for Solving the Problems]
The magnetostrictive fuel injection valve of the internal combustion engine of the present invention has a cylindrical casing in which the inside is a fuel passage, an injection nozzle is attached to one end, a fuel introduction pipe is connected to the other end, and the outside is not a fuel passage. And a magnetostrictive element tube coaxially inserted into the casing and having one end as a locking end and the other end being a free end, and being coaxially inserted into the magnetostrictive element tube and having one end A rod connected to the valve element disposed in the injection nozzle and having the other end engaged with the free end of the magnetostrictive element tube, and installed on the outer periphery of the casing that is not a fuel passage, applies a magnetic field to the magnetostrictive element tube And an electromagnetic coil.
[0005]
【The invention's effect】
In this invention, the electromagnetic coil which applies a magnetic field to a magnetostriction element is installed in the outer periphery of the cylindrical casing which is the outer side of a fuel passage. For this reason, the trouble which the corrosive substance in a fuel corrodes an electromagnetic coil can be prevented, and long-term use is possible. 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.
[0006]
According to the first and third aspects of the present invention, a movable bush is connected to the free end of the magnetostrictive element tube, and a hook that engages with the end surface of the movable bush is provided at the other end of the rod. It is biased in the direction of one end. With this configuration, the valve opening of the injection nozzle can be easily opened, and it is possible to reliably prevent the problem that the deposit adheres to the valve body and the injection rate becomes inaccurate as in the case of the external opening.
[0007]
The arrangement according to claim 1 and 4, the fuel introduction pipe, inside which a fuel passage is screwed an adjustment (the adjusting) pipe for adjusting the biasing force of the spring. The spring load can be easily adjusted by turning the adjusting pipe. For this reason, it is possible to make the opening and closing times of the valves uniform with a simple operation, and the injection rate can be adjusted accurately. In addition, it is desirable to attach the rotation prevention means by vibration to the adjustment pipe.
[0008]
In the configuration according to the second aspect , since the thermal expansion of the magnetostrictive element and the rod is approximated, it is possible to compensate for a temperature change due to an accurate temperature rise of the fuel 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]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a magnetostrictive fuel injection valve 10 of a direct injection gasoline engine according to the present invention, and includes a cylindrical casing 1 having a fuel passage 11 inside. A fuel introduction pipe 2 is connected to the upper end of the casing 1, and an injection nozzle 3 is attached to the 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 the cylinder of the engine.
[0010]
The casing 1 is made of a non-magnetic 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 locked to the inner peripheral edge 12 and an upper end 42 which is a free end, and can be extended upward. A lower end portion of the fuel introduction pipe 2 is screwed into the casing 1, and a gap 22 is provided between the lower end face 21 of the fuel introduction pipe 2 and the upper end face 43 of the magnetostrictive element pipe 4.
[0011]
In the gap 22, a movable bush 45 is installed in contact with the upper end 42 of the magnetostrictive element tube 4, and a disc spring 44 is provided between the outer portion of the upper surface of the movable bush 45 and the lower end surface 21 of the fuel introduction pipe 2. Is intervening. In the magnetostrictive element tube 4, the rod 5 is coaxially inserted through the movable bush 45 with its upper end positioned. The linear expansion of the rod 5 is made to coincide with 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.
[0012]
The movable bush 45 is formed with a slit 46 for securing a fuel passage between 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. The flange 52 is engaged with the inner side of the upper surface of the movable bush 43, and the rod body 53 is connected to the movable bush 45. The lower end extends into the injection nozzle 3 through the inside and the center of the magnetostrictive element tube 4.
[0013]
An adjustment pipe 23 having a fuel passage inside is screwed into the fuel introduction pipe 2, and a spring 24 is interposed between the adjustment pipe 23 and the flange 52 so that the rod 5 moves downward ( (Pressing side closed) The spring load of the spring 24 can be adjusted by the rotation of the adjusting pipe 23, and the acting force required to open the valve can be increased or decreased. As a result, the valve opening time can be accurately adjusted, which is effective for proper control of the injection rate.
[0014]
The injection nozzle 3 includes a cylindrical valve body 31 fitted to the lower end of the casing 1 and a ferromagnetic nozzle body 32 fitted to the lower end of the valve body 31. In the nozzle body 32, a needle 6 as a valve body connected to the lower end 54 of the rod body 53 is inserted. An injection hole 33 is formed at the tip of the nozzle body 32, and a sheet surface 34 is provided on the inner periphery.
[0015]
The upper end of the needle 6 is a large diameter portion 62 with a recess 61, and the lower end 54 of the rod body 53 is fitted. A flange 63 having substantially the same diameter as the large diameter portion 62 is provided at the lower portion of the needle 6, and a fuel passage hole 64 is formed in the flange 63. The collar 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.
[0016]
An electromagnetic coil 7 for applying a magnetic field to the magnetostrictive element tube 4 is fitted on the outer periphery of the casing 1 and surrounded by a ferromagnetic outer tube 71. In this embodiment, the electromagnetic coil 7 includes a bobbin 72 fitted on the casing 1 and a conductive wire 73 wound around the bobbin 72. Of course, the electromagnetic coil may be formed by directly winding the coated conductor around the casing 1.
[0017]
In the present invention, when the electromagnetic coil 7 is energized by the control circuit 8, 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, and the injection hole 33 opens inward to inject fuel.
[0018]
According to the configuration of this embodiment, since the electromagnetic coil 7 is disposed outside the casing (outside the fuel passage), it can be reliably prevented from being corroded by corrosive liquid such as water contained in the fuel, A magnetostrictive fuel injection valve that is excellent in durability and can be used for a long time can be manufactured. In addition, it is possible to effectively prevent changes in the injection rate due to a rise in fuel temperature or deposits, and it is easy to adjust the injection rate.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a fuel injection valve for 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 tube 41 Lower end (locking end)
42 Upper end (free end)
45 Movable bush 5 Rod 6 Needle (valve)
63 鍔 7 Electromagnetic coil

Claims (4)

The inside is a fuel passage, an injection nozzle is attached to one end, a fuel introduction pipe is connected to the other end, and a cylindrical casing whose outer side is not a fuel passage is coaxially inserted into the casing. A magnetostrictive element tube having one end as a locking end and the other end as a free end, and is coaxially inserted into the magnetostrictive element tube, and one end is connected to a valve element disposed in the injection nozzle. , met magnetostrictive fuel injector comprising a solenoid coil for applying a rod the other end engaged with the free end of the magnetostrictive element tube was placed in the outer periphery of the casing is not a fuel passage a magnetic field to the magnetostrictive element tube And
A movable bush is connected to the free end of the magnetostrictive element tube, and a hook that engages with an end surface of the movable bush is provided at the other end of the rod. The hook is biased in one direction by a spring,
2. A magnetostrictive fuel injection valve, wherein an adjusting pipe for adjusting a biasing force of the spring is screwed into the fuel introduction pipe . The inside is a fuel passage, an injection nozzle is attached to one end, a fuel introduction pipe is connected to the other end, and a cylindrical casing whose outer side is not a fuel passage is coaxially inserted into the casing. A magnetostrictive element tube having one end as a locking end and the other end as a free end, and is coaxially inserted into the magnetostrictive element tube, and one end is connected to a valve element disposed in the injection nozzle. A magnetostrictive fuel injection valve comprising a rod whose other end is locked to a free end of the magnetostrictive element tube, and an electromagnetic coil that is installed on the outer periphery of the casing that is not a fuel passage and applies a magnetic field to the magnetostrictive element tube. And
A magnetostrictive fuel injection valve characterized in that the linear thermal expansion of the rod approximates the linear thermal expansion of the magnetostrictive element tube . 3. The magnetostrictive fuel injection valve according to claim 2, wherein a movable bush is connected to a free end of the magnetostrictive element tube, and a hook that engages with an end surface of the movable bush is provided at the other end of the rod. A magnetostrictive fuel injection valve characterized in that the rod is biased in one direction by a spring . 4. The magnetostrictive fuel injection valve according to claim 3 , wherein an adjusting pipe for adjusting a biasing force of the spring is screwed into the fuel introduction pipe .

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