JP2003148285A - Fluid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly inject fuel, to increase the pass-through distance of the fuel, to form fine fuel particles, to inject liquid fuel and gaseous fuel by the same fuel injection device, and to accurately control an injection time. SOLUTION: An injector body 12 of an injector 11 is formed with a recessed cavity 13 at the tip thereof, and the tip of the cavity 13 is provided with an orifice plate 15. The injector body 12 is provided with a cylindrical center electrode 17, and the tip 17a of the center electrode 17 is positioned in the bottom 13a of the recessed cavity 13. A material to be injected is supplied to the recessed cavity 13 through the cylindrical center electrode 17. A high- voltage discharging device 21 is connected to the center electrode, and the material to be injected inside the cavity 13 is injected by discharge generated between the tip 17a of the center electrode 17 and the orifice plate 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid injection device, and more specifically to a fluid injection device capable of injecting a fluid such as liquid fuel and gas fuel into a combustion chamber of an engine.

[0002]

2. Description of the Related Art Conventionally, in order to reduce harmful exhaust gas components such as PM discharged from a diesel engine, research and development such as high-pressure fuel injection have been conducted. Further, in the conventional fuel injection device, the fuel injection device is individually used according to the liquid fuel, the gas fuel and the like.

[0003]

However, the conventional fuel injection device described above has a drawback that the combustion speed is slow, rapid fuel injection cannot be performed, and the fuel penetration distance becomes short when the fuel injection is slow. Was there. Further, the fuel injection device must be used individually depending on the liquid fuel and the gas fuel, and the same fuel injection device cannot be used to inject and spray the fuel, and the injection timing is accurately controlled. It had the drawback that it could not.

Therefore, the present invention has been made by paying attention to the unsolved problems of the above-mentioned conventional example, and can rapidly inject a fluid such as fuel, the fluid can be ejected at a high speed, and the penetration distance of the fluid can be increased. The liquid fuel and the gas fuel can be made finer, and it is not necessary to separately use the fuel injection device according to the liquid fuel and the gas fuel, and the liquid fuel and the gas fuel can be used by using the same fuel injection device. It is an object of the present invention to provide a fluid ejecting apparatus which is capable of injecting and which is capable of accurately controlling the injection timing and which is excellent in economic efficiency.

[0005]

In order to achieve the above object, a fluid ejecting apparatus according to claim 1 of the present invention has an injector main body having a concave cavity formed at its tip,
An orifice plate is provided at the tip of the concave cavity of the injector body, a cylindrical center electrode is provided at the injector body, and the tip of the tubular center electrode is located at the bottom of the concave cavity. A fluid is supplied to the concave cavity through the center electrode of, and a high-voltage discharge device is connected to the cylindrical center electrode, and the fluid supplied to the concave cavity is connected between the tip of the center electrode and the orifice plate. It is characterized in that it is ejected by a discharge between them.

According to the first aspect of the present invention, the injector main body is provided with the tubular center electrode, the tip of the tubular center electrode is located at the bottom of the concave cavity, and the tubular center electrode is interposed therebetween. By supplying a fluid to the concave cavity and operating the high-voltage discharge device connected to the center electrode, high-voltage discharge can be performed from the tip of the center electrode toward the orifice plate. The fluid supplied to the cavity can be jetted.

A fluid ejecting apparatus according to a second aspect is the fluid ejecting apparatus according to the first aspect, wherein the injector body is made of tetrafluoroethylene, the cylindrical center electrode is made of a stainless pipe, and the orifice is formed. It is characterized in that the plate is made of stainless steel.

In the invention according to claim 2, since the injector body is made of tetrafluoroethylene and the center electrode is made of a stainless pipe, the fluid is supplied to the concave cavity through the stainless pipe. Therefore, high voltage discharge can be performed from the tip of the center electrode toward the orifice plate, and the fluid supplied to the concave cavity can be jetted by this high voltage discharge.

Further, a fluid injection device according to a third aspect of the present invention is the fuel injection device according to the first or second aspect, wherein the fluid injection device is formed so as to face the combustion chamber of the engine. Fuel is supplied to the fuel injection device via a fuel pump, and the fuel is injected into the combustion chamber by the fuel injection device.

According to the third aspect of the invention, since the fluid injection device is formed in the fuel injection device which is provided so as to face the combustion chamber of the engine,
It is possible to promote the diffusive mixing of air and fuel, increase the combustion speed, enable rapid fuel injection, increase the fuel penetration speed at a high speed, and make the fuel particles finer. it can.

Furthermore, a fluid ejecting apparatus according to a fourth aspect of the present invention is the fluid ejecting apparatus according to the first to third aspects,
The high-voltage discharge device includes a high-voltage charging circuit unit, a high-voltage discharging circuit unit, and a trigger circuit unit, a perforated sphere gap is provided in the high-voltage discharging circuit unit, and the perforated sphere gap is used as a starting gap. It is characterized by

In the invention according to claim 4 of the present invention, the high-voltage discharging device comprises a high-voltage charging circuit part, a high-voltage discharging circuit part and a trigger circuit part, and the high-voltage discharging circuit part has a perforated spherical gap. Since the perforated spherical gap is used as the starting gap, rapid fuel injection can be performed, the fuel injection can be performed at high speed, the fuel penetration distance can be increased, and the fuel particles can be miniaturized. The timing can be controlled accurately.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fluid ejection device of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of a fluid injection device according to the present invention. In the present embodiment, the case where the present invention is applied to a diesel engine will be described, but the present invention is not limited to the diesel engine, and It can also be used as an ignition device when a mixture is supplied to an engine and burned using an ignition plug like a gasoline engine.

As shown in FIG. 1, the diesel engine 1 comprises a cylinder 2 and a piston 3, and a combustion chamber 5 is formed on the head side of the piston 3. Further, an intake / exhaust valve is provided in the cylinder 2, a piston rod 6 is connected to the piston 3, a piston ring or the like is provided on an outer peripheral surface which is a sliding surface of the piston 3, and other various types of diesel engine 1 are provided. A conventionally known configuration is provided.

A fluid ejecting device 11 is provided in the cylinder 2 facing the substantially center of the head of the piston 3.
This fluid injection device 11 is formed as a fuel injection device in the present embodiment. As shown in FIGS. 2 and 3A and 3B, the fluid ejection device 11 has a cavity 13 with a concave end.
The injector main body 12 is formed. The concave cavity 13 is formed in a cylindrical shape in the present embodiment, but is not limited to the cylindrical shape.

The injector body 12 is formed of a tetrafluoroethylene column or the like. The injector body 12 is not limited to being made of tetrafluoroethylene, but can be made of other insulating material. An orifice plate 15 made of stainless steel is provided at the tip of the concave cavity 13 of the injector body 12. A circular orifice 15a is formed in the orifice plate 15.

A cylindrical center electrode 17 is provided on the injector body 12, and the tip 1 of the cylindrical center electrode 17 is provided.
A center electrode 17 is held by a holder 18 so that 7a is located at the bottom 13a of the concave cavity 13, and a fluid such as liquid fuel or gas fuel is supplied to the concave cavity 13 through the cylindrical central electrode 17. It In FIGS. 2 and 3A and 3B, reference numeral 19 is a rubber and 20 is an O-ring.

The cylindrical center electrode 17 is formed of a stainless pipe. The fluid such as the liquid fuel or the gas fuel is supplied from the fuel tank 9 to the cylindrical center electrode 17 through the fuel pump 8, and is supplied from the cylindrical center electrode 17 to the concave cavity 13. Fuel is injected into the combustion chamber 5 by the fuel injection device 11. As shown in FIG. 3B, the concave cavity 13 has a depth L1 and a diameter L2 of about 4 mm to 6 mm, and the circular orifice 15a has a diameter L3 of about 1 mm to 4 mm.

A condenser type high voltage discharge device 21 is connected to the cylindrical center electrode 17, and the fluid supplied to the concave cavity 13 is applied to a high voltage between the tip 17a of the center electrode 17 and the orifice plate 15. Is applied.
The center electrode 17 and the orifice plate 15 are not limited to stainless steel, and other conductive metals can be used.

The capacitor type high voltage discharge device 21 is
As shown in FIG. 4, it comprises a high voltage charging circuit section 22, a high voltage discharging circuit section 23 and a trigger circuit section 24. The high-voltage charging circuit unit 22 supplies the AC voltage of the commercial AC power supply 25 to the step-up transformer 27 via the sliderac 26,
The step-up transformer 27 boosts the voltage to about 15 kV, and the rectifier circuit 28, whose positive electrode output side is grounded, rectifies it to convert it into a DC high voltage, and this DC high voltage is charged and discharged.
9 to charge. A ball electrode 30 is connected to the negative electrode side of the charging / discharging capacitor 29.

The high-voltage discharge circuit section 23 has a perforated sphere having needle electrodes 31a having a diameter of about 1.5 mm, which are arranged inside the spherical electrode 30 of the high-voltage charge circuit section 22 at a predetermined distance. The electrode 31 is provided, the central electrode 17 is connected to the perforated spherical electrode 31, and the orifice plate 15 is grounded.

Further, the trigger circuit section 24 has a rectifier circuit 33 for rectifying the commercial AC power source 32, a switching circuit 34 having a trigger switch 34a connected to the output side of the rectifier circuit 33, and a positive output of the rectifier circuit 33. Side and the negative electrode output side, a capacitor 35 and a step-up transformer 36 that are inserted in series, and a DC high voltage of about 6 kV output from the output side of the step-up transformer 36 are provided with a perforated ball of the high-voltage discharge circuit section 23. The diode 37 is provided to the needle-shaped electrode 31a of the electrode 31.

Then, the charging / discharging capacitor 29 of the high voltage charging circuit 22 is stepped up by the step-up transformer 27, and the rectifying circuit 2
The switch 34a of the switching circuit 34 in the trigger circuit section 24 is charged with the DC high voltage rectified by
Is turned on, the DC voltage charged in the capacitor 35 is discharged, and this is the step-up transformer 27.
Is increased to 6 kV and is applied to the needle-shaped electrode 31a of the perforated spherical electrode 31 through the diode 37 to generate discharge between the needle-shaped electrode 31a and the perforated spherical electrode 31, Arc discharge is induced between the perforated sphere electrode 31 and the opposing sphere electrode 30 to cause dielectric breakdown, whereby the high DC voltage charged in the charging / discharging capacitor 29 is applied to the central electrode 17 and the orifice plate 15. By applying the voltage between them, a discharge is generated between them and plasma is generated in the cavity.

According to the present invention, the temperature of the weakly ionized plasma generated by the discharge is as high as about 2000 to 6000 ° C., so that the chemical reaction rate is increased and thus the combustion rate is increased. Further, the chemically active intermediate product generated by the high temperature further increases the chemical reaction rate, which increases the burning rate.

Further, since the discharge time of the capacity discharge is 1 ms or less, rapid fuel injection becomes possible. In a normal diesel engine, fuel is injected under a constant injection pressure, and the injection amount is controlled by the injection time. In the present invention, no matter what the volume of fuel, the fuel is injected by one short-time discharge, so that rapid injection is possible.
Further, since the injection speed is high, the fuel penetration distance increases. That is, since the fuel is injected by the discharge for a short time, the fuel injection speed is rapid, and the kinetic energy of the fuel increases with the increase of the injection speed, and reaches a long distance. Moreover, since the fuel injection speed is rapid, the fuel is atomized.

Next, the influence of the shape of the fluid injection device 11 on the fuel spray will be described by photographing the fuel spray process induced by the high voltage discharge using the fluid injection device 11 according to the present invention. FIG. 5 shows a fluid ejection device 11 according to the present invention.
The shape used in the experiment is shown. The parts corresponding to those of the fluid ejecting apparatus 11 shown in FIG. 2 are denoted by the same reference numerals and detailed description thereof will be omitted. A container 53 is provided which forms a cylindrical combustion chamber 51 having L4 of 80 mm and thickness L5 of 20 mm.

The concave cavity 13 is formed in a cylindrical shape and has three different sizes. The first has a diameter of 4 mm, a depth of 4 mm, and a volume of 50.3 mm ³ .
The third has a diameter of 5 mm, a depth of 5 mm, and a volume of 98.2 mm ³ ,
The third has a diameter of 6 mm, a depth of 6 mm, and a volume of 169.6 mm ³ . The size of the circular orifice 15a used was 1 mm or 4 mm in diameter. Further, methanol was used as a fuel, and an amount corresponding to the volume of the cavity 13 was filled.

FIG. 6 shows an outline of the experimental device 61. The experimental device 61 is a fluid ejecting device 1 attached to a container 53.
1, a capacitor type high voltage discharge device 21 connected to the fluid ejecting device 11, and a trigger circuit unit 24 of the high voltage discharge device 21, and are configured by a light source 63, reflecting mirrors 65 and 66, and a high speed camera 68. To be done. The image from the high speed camera 68 is displayed on the display device 7 from the personal computer 71.
It is displayed in 3. The fuel was sprayed in air at room temperature and atmospheric pressure, and was photographed by a high-speed camera 68 using the schlieren method to clarify the spray state. The electric energy for discharging was 5.0 J by charging the capacitor 24 having a capacity of 0.1 μF at a voltage of 10 KV.

FIGS. 7 and 8 show changes with time in fuel spray. FIG. 7 shows the case where the diameter of the circular orifice 15a is 1 mm, and FIG. 8 shows the case where the diameter of the circular orifice 15a is 4 mm. In FIG. 7, the cavity 13 has a diameter of 5 mm and a depth of 5
In the case of mm, the ejection speed of the fuel is faster than the diameter of the cavity 13 of 4 mm, the depth of 4 mm and the diameter of 6 mm, and the depth of 6 mm. After 1.0 ms, it collides with the opposite wall of the container 53.

However, in the case of the cavity 13 having a diameter of 4 mm and a depth of 4 mm, and in the case of a diameter of 6 mm and a depth of 6 mm, a rapid fuel expansion is not shown in the initial stage after the discharge, and 0.7 after the discharge.
The fuel spray reaches the vicinity of the central portion of the cylindrical container 53 in 5 ms. Therefore, the diameter of the circular orifice 15a is 1 mm, the diameter of the cavity 13 is 5 mm,
It can be seen that the fluid ejection device 11 having a depth of 5 mm is effective.

As shown in FIG. 8, when the diameter of the circular orifice 15a is 4 mm, the fuel injection angle is large in all the cavities 13 as compared with the case where the diameter of the orifice 15a is 1 mm, and it is understood that the fuel is injected in a wide range. In particular, after 0.5 ms after the discharge, the fuel that has reached the vicinity of the central portion of the cylindrical container 53 diffuses throughout the container 53. It is considered that this is because the area of the orifice 15a is large and the effect of the orifice 15a is small. Therefore, the fluid ejection device 11
The shape influences the state of fuel spray, and it is desirable for the fuel injection device of a diesel engine to have a large orifice diameter.

[0032]

As described above, according to the first aspect of the present invention.
According to the fluid ejecting apparatus of the present invention, the injector main body is provided with the cylindrical center electrode, the tip of the cylindrical center electrode is located at the bottom of the concave cavity, and the cylindrical center electrode has a concave shape. By supplying a fluid to the cavity and operating a high-voltage discharge device connected to the center electrode, a high-voltage discharge can be made from the tip of the center electrode toward the orifice plate. The supplied fluid can be jetted.

Further, according to the fluid ejecting apparatus of the second aspect of the present invention, since the injector body is made of tetrafluoroethylene and the center electrode is made of the stainless pipe, the concave shape is formed through the stainless pipe. It is possible to supply a fluid to the cavity of No. 2, and to perform high-voltage discharge from the tip of the center electrode toward the orifice plate, and this high-voltage discharge can eject the fluid supplied to the concave cavity.

Further, according to the fluid injection device of the third aspect of the present invention, since the fluid injection device is formed in the fuel fluid injection device provided facing the combustion chamber of the engine,
As fuel injection of engine, diffusion mixing of air and fuel is promoted, combustion speed can be increased, rapid fuel injection can be performed, fuel injection can be performed at high speed, and fuel penetration distance can be increased. Can be miniaturized.

According to a fourth aspect of the fluid ejecting apparatus of the present invention, the high-voltage discharging device includes a trigger circuit section, a high-voltage charging circuit section, and a high-voltage discharging circuit section, and the trigger circuit section includes Since the perforated sphere gap is provided and the perforated sphere gap is used as the starting gap, rapid fuel injection can be performed, the fuel injection can be performed at high speed, and the fuel penetration distance can be increased, and the fuel particles can be miniaturized. Therefore, the injection timing can be accurately controlled.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional explanatory view showing an embodiment in which a fluid injection device according to the present invention is applied to a diesel engine.

FIG. 2 is a cross-sectional view of a fluid ejection device according to the present invention.

3A and 3B show a cavity at a tip of an injector body of a fluid ejection device according to the present invention, in which FIG. 3A is a partial sectional perspective view and FIG. 3B is a sectional view.

FIG. 4 is a circuit diagram of a capacitor-type high-voltage discharge device connected to a fluid ejection device according to the present invention.

FIG. 5 is a cross-sectional view showing a shape used in an experiment of a fluid ejection device according to the present invention.

FIG. 6 is a schematic diagram of an experimental device for a fluid ejection device according to the present invention.

FIG. 7 is a view showing a temporal change of fuel spray when the diameter of the circular orifice of the fluid injection device according to the present invention is 1 mm.

FIG. 8 is a diagram showing a temporal change in fuel spray when the diameter of the circular orifice of the fluid injection device according to the present invention is 4 mm.

[Explanation of symbols]

1 diesel engine 2 cylinders 3 pistons 5 Combustion chamber 6 piston rod 8 fuel pump 9 Fuel tank 11 Fluid ejection device 12 Injector body 13 concave cavity 13a bottom 15 Orifice plate 15a circular orifice 17 Center electrode 17a tip 18 holder 21 Capacitor type high voltage discharge device 22 High voltage charging circuit 23 High voltage discharge circuit 24 Trigger circuit section 26 Slideac 27 Step-up transformer 28 Rectifier circuit 29 Charge / discharge capacitors 30 ball electrode 31 Perforated sphere electrode 31a Needle electrode 33 Rectifier circuit 34 Switching circuit 34a Trigger switch 35 capacitor 36 step-up transformer 37 diode 51 Combustion chamber 53 containers 61 Experimental device 63 light source 65 Reflector 66 Reflector 68 high speed camera 71 PC 73 Display

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Claims (4)

[Claims] 1. An injector main body having a concave cavity formed at its tip, an orifice plate is provided at the tip of the concave cavity of the injector main body, and a cylindrical center electrode is provided at the injector main body. The tip of the cylindrical center electrode is located at the bottom of the concave cavity, fluid is supplied to the concave cavity through the cylindrical center electrode, and a high voltage discharge device is connected to the cylindrical center electrode. A fluid ejecting apparatus, characterized in that the fluid supplied to the concave cavity is ejected by electric discharge between the tip of the center electrode and the orifice plate. 2. The injector body is made of tetrafluoroethylene, the cylindrical center electrode is made of a stainless pipe, and the orifice plate is made of stainless steel.
The fluid ejection device described. 3. The fluid injection device is formed in a fuel injection device provided opposite to a combustion chamber of an engine, and the fuel is supplied to the fuel injection device via a fuel pump. The fluid injection device according to claim 1 or 2, wherein the fuel injection device is configured to inject the fuel into the combustion chamber. 4. The high-voltage discharge device includes a high-voltage charging circuit unit, a high-voltage discharging circuit unit, and a trigger circuit unit, and the high-voltage discharging circuit unit is provided with a perforated sphere gap, and the perforated sphere gap is provided. The fluid ejecting apparatus according to claim 1, wherein the fluid ejecting apparatus is used as a starting gap.