阅读说明：本技术 液滴喷射装置 (Liquid droplet ejecting apparatus ) 是由 斋藤文修 池田时广 田村真司 于 2019-12-26 设计创作，主要内容包括：在具备对液体的微小液滴进行喷射的喷射口的液滴喷射装置中,使喷射口61或喷射装置与车体等导体10电气导通,增大喷射口61或喷射装置的静电电容,抑制由于液体的流动带电而产生的液体与喷射口61之间的电位差的扩大。当该电位差很大时,库伦力作用于带电的液滴与带静电的喷射口之间,而发生液滴的排出的延迟或不充分排出等问题,但是,通过增大喷射口61或喷射装置的静电电容,从而解决了这样的问题。(In a droplet ejection apparatus having an ejection port for ejecting fine droplets of a liquid, the ejection port 61 or the ejection apparatus is electrically conducted to a conductor 10 such as a vehicle body, and the electrostatic capacitance of the ejection port 61 or the ejection apparatus is increased to suppress the expansion of a potential difference between the liquid and the ejection port 61 due to the flow electrification of the liquid. When the potential difference is large, coulomb force acts between the charged droplets and the electrostatically charged ejection openings, and problems such as delay in ejection of droplets and insufficient ejection occur, but such problems are solved by increasing the electrostatic capacitance of the ejection openings 61 or the ejection device.)

1. A liquid droplet ejecting apparatus having an ejection port for ejecting a liquid droplet, characterized in that,

the ejection opening has one or more ejection holes through which the liquid droplets are ejected,

the ejection opening or the droplet ejection apparatus is electrically conducted to a conductor so as to suppress an increase in potential due to the flow electrification of the droplets, and the electrostatic capacitance of the ejection opening or the droplet ejection apparatus is made larger than that in a state where the ejection opening or the droplet ejection apparatus is not conducted to the conductor.

2. A liquid droplet jetting apparatus as claimed in claim 1,

the conductor is an ejection target from which the liquid droplet is ejected from the ejection port.

3. A liquid droplet jetting apparatus as claimed in claim 1,

further comprises an electrode disposed in front of the ejection opening,

the liquid droplets ejected from the ejection openings are accelerated by an electric field formed by applying a voltage to the electrodes.

4. A liquid droplet jetting apparatus as claimed in claim 1,

the ejection opening has one or more electrodes in an interior thereof that control ejection of the liquid,

controlling a timing and an ejection amount of ejection of the liquid pressurized so as to be ejected from the ejection port by switching a potential of the electrode.

5. A droplet ejection apparatus according to claim 2,

applying a positive voltage to the ejection object to increase a probability of collision of the droplets negatively charged due to flow electrification with the ejection object.

6. A liquid droplet jetting apparatus as claimed in claim 1,

the mechanism for ejecting the liquid droplets from the ejection opening includes: a pressure chamber communicating with the ejection port, a diaphragm that varies a volume of the pressure chamber, an actuator that drives vibration of the diaphragm, a controller that controls driving of the actuator, and a detector that provides information of a vehicle to the controller,

the controller controls the actuator based on information from the detector to vibrate the vibration plate, thereby ejecting a droplet of the liquid contained in the pressure chamber from the ejection opening, the ejection opening of the ejection opening having a diameter of 50 μm or less, the droplet having a particle diameter of 50 μm or less.

Technical Field

The present invention relates to a device for ejecting liquid in the form of fine droplets, the liquid being used in an internal combustion engine (engine), an ink jet printer, or the like.

Background

As an injection device that injects a liquid in a state of fine droplets toward an object to be injected, there is a technology that improves the thermal efficiency of an internal combustion engine (engine) by optimizing the combustion of fuel, for example. When the liquid passes through the ejection device or the vaporizer, electrification of the flow occurs, the ejection device or the vaporizer and the liquid are charged positively and negatively, respectively (depending on the combination of substances, there are also cases of charging negatively and positively), and coulomb attraction acts between the liquid droplet and the ejection device or the like. The smaller the diameter of the droplet, the greater the pressure required for ejecting the droplet, and this is mainly due to coulomb attraction caused by the flow electrification.

The technique of the present invention contributes to surface processing such as coating and high dot density printing by ink jet. Further, in the internal combustion engine, a technique is provided to overcome a decrease in the combustion ratio of fuel caused by a delay in the discharge and a delay in vaporization of fuel droplets due to the coulomb attraction, thereby achieving high thermal efficiency and large output and torque, and reducing the content ratio of hydrocarbons in the exhaust gas by increasing the combustion ratio.

The present invention relates to a technique for generating fine droplets for improving thermal efficiency by optimizing fuel combustion in surface modification, production of a very thin film multilayer three-dimensional structure, and an internal combustion engine (engine). In generating fine droplets by ejecting liquid from an ejection port having a fine ejection hole, a large pressure is required. The specific surface area (the ratio of the surface area per volume or mass) of the liquid becomes large in inverse proportion to the diameter of the ejection orifice, and therefore, the flow charging effect occurring in the interface of the solid surface and the liquid apparently occurs in the generation of the minute liquid droplets. In ejecting a liquid against the coulomb attraction acting on the liquid molecules of dielectric polarization acting between the electric charge (negative and positive depending on the combination of substances) introduced into the liquid by the flow electrification and the fine droplet ejection device or the ejection port thereof, it is necessary to apply a large pressure to the liquid. When the technique of the present invention for electrically controlling the charged liquid and the fine droplets is used, the fine droplets can be ejected from the ejection openings with a pressure smaller than that of the prior art. Can be used for surface modification such as coating and construction of a very thin film multilayer three-dimensional structure by ink jet. Further, when applied to an internal combustion engine, since the combustion ratio of minute fuel droplets is high, it is possible to achieve high thermal efficiency and large output and torque, and to reduce the content ratio of the hydrocarbon component in the exhaust gas.

If the ejection timing and the ejection amount can be controlled so that the diameter of the liquid droplet becomes, for example, -10 μm, it is considered that innovative clusters of various fields are generated. Control of the film thickness of the coating by the use of fine droplets, improvement of the decorative properties, increase of the dots for printing, and increase of the density of information are expected. In addition, the densification of organic semiconductor integrated circuits, extremely thin multilayer thin-film substrates, and large-area integrated circuits using an ink jet printer can be accelerated. Further, innovation of the internal combustion engine can be achieved. Internal combustion engines (engines) are one of the most important power sources in vehicles such as automobiles and other industrial fields, and have been in a highly developed technical field. Regarding the thermal efficiency of the internal combustion engine, it is as low as 20% to 30% in the case of a gasoline engine and as low as 30% to 40% in the case of a diesel engine, and it is lower than the efficiency of other heat engines, and there is a large margin for improvement. The formation of the mixture, and the adequacy of intake and combustion, which determine the thermal efficiency, depend on the timing of intake, ignition, compression and exhaust, which are controlled mechanically or electronically. The time required for these processes is as short as several hundred microseconds to 10 milliseconds, and the conditions of temperature, pressure, and mixture gas vary with the rotation speed of the engine. Therefore, the physical and chemical phenomena in these processes are not limited to those that have not been clarified (see non-patent document 1).

Recently, the present inventors measured the potential difference between the potential of the fuel carburetor, the fuel injection device, and the engine during operation and the ground potential, and found that these potential differences periodically fluctuate (see fig. 31 to 36). Fig. 31 shows the results of potential measurement of a fuel injection device (injector) mounted on a conventional motorcycle (HONDA MEN 450, manufactured by HONDA industries, ltd.) and the engine speed is 6900 rpm. The injector is insulated from an object to be injected, which is an object of fuel injection. The two arrows shown in the figure indicate failure of fuel injection. Fig. 32 is an enlarged view of the initial impulse shown in fig. 31. This shows that 1 impulse consists of multiple voltage rises and pulse oscillations. Fig. 33 is a further enlarged view of fig. 32, showing that there is a potential rise of about 3V at maximum before the pulse oscillation. Fig. 34 shows the result of potential measurement of the internal combustion engine (engine) mounted on the conventional motorcycle shown in fig. 31, and the engine speed is 7300 rpm. The engine is in a state of being insulated from the injector. As shown in the figure, it can be seen that a periodic impulse is attached to the noise of the voltage variation. Fig. 35 is an enlarged view of the initial impulse shown in fig. 34. This shows that 1 impulse consists of a fall of multiple voltages and a pulse oscillation. Fig. 36 is a further enlarged view of fig. 35, showing that there is a drop in potential of about 0.6V at maximum before the pulse oscillation.

The variation in the potential difference is due to the flow electrification that introduces negative charges (electrons) into the gasoline from the fuel vaporizer and the walls of the fuel injection device. Flow electrification can be considered as a friction phenomenon in a broad sense. When two different dielectrics are rubbed, static electricity is generated to be respectively positively and negatively charged, which is known from ancient History. The 2 objects that are charged are not limited to dielectrics, but can also occur in conductors or fluids. The friction force is proportional to the weight of the object. Furthermore, the frictional force does not depend on the apparent contact area of a macroscopic solid, but is proportional to the actual contact area at the microscopic molecular level. In the interface between the liquid and the solid, it is considered that the apparent contact area and the actual contact area are almost equal, and therefore, it is considered that the amount of charge per unit volume of the fluid generated by the flow electrification becomes larger with the contact area of the fluid.

It has been known for a long time that the flowing charge is generated (see non-patent document 2), and it has been reported that an explosion accident occurs in a feed pipe, an oil storage tank, or the like due to discharge caused by a high electric field generated by charge accumulation. Therefore, studies on flow electrification are prevalent (t. pailat, g. touchhard and y. Bertrand, Sensor, 2012, 12, 14315-. However, the physical/chemical mechanism of occurrence of flow electrification or the manner of discovery has not been clarified yet, and therefore, quantitative research progress is desired.

It is considered that the polarity of the charge of the charged droplets is determined by the combination thereof with the material of the device. In the present specification, in the following description, the polarity of the liquid droplet is described as negative to facilitate understanding, but the case where the polarity is positive is not excluded.

Documents of the prior art

Non-patent document

Non-patent document 1: advanced engine technology, Heintz Heisler, 2009, Butterworth-Heinemann

Non-patent document 2: electrostatics in Petroleum Industry The preservation of expansion Hazards, A, Klinkerberg and J.L. van der Minne, 1958, Elsevier, Amsterdam, The Netherlands.

Disclosure of Invention

Problems to be solved by the invention

As described above, the thermal efficiency of the internal combustion engine is lower than that of other heat engines, and the room for improvement is large. The present inventors have clarified that: when liquid is ejected from an ejection device, delay in discharge of liquid droplets or insufficient discharge of liquid droplets may occur as the liquid passes through, and one of the causes is the following phenomenon: when a liquid is ejected from an ejection apparatus, flowing electrification occurs with the passage of the liquid, coulomb force acts between the charged liquid droplets and the electrostatically charged ejection openings, and problems such as delay in the ejection of the droplets or insufficient ejection of the droplets occur due to the coulomb force.

The present invention has been made in view of such circumstances, and provides a highly efficient droplet ejection apparatus that controls the influence of flow electrification.

In an internal combustion engine using a fine droplet ejection apparatus, when coulomb attraction acts between a fuel liquid having different sign charges generated due to flow electrification and an ejection port, a delay is generated in the discharge timing of the fuel droplets, and a part of the fuel droplets is not introduced into a cylinder. Further, the results of the engine sound measurement and the power measurement test conducted by the present inventors and the like show that: in order to achieve a large combustion ratio and a large output, it is important to increase the efficiency of vaporization of fuel droplets in the cylinder.

The present inventors have developed a fuel injection device, which is an example of the fluid injection device, based on these findings, and which controls the coulomb force acting on the fuel liquid and droplets ejected from the fuel carburetor or the indirect injection type and direct injection type fuel injection devices, and further developed a fuel injection device which efficiently injects fine fuel droplets that are easily vaporized in a short time and controls the injection amount in accordance with the rotation speed of the engine.

A method of applying pressure to a liquid to intermittently eject the liquid from an ejection hole in order to generate liquid droplets is simple and easy to control, and is therefore extremely important in practical use. When the diameter of the ejection hole is made smaller in order to eject small droplets, the contact area of the liquid becomes larger in inverse proportion to the diameter of the ejection hole, and therefore the resistance to friction (fluid friction) becomes larger, and a large pressure is required. Further, coulomb attraction generated by the flow electrification is applied as resistance, and thus, ejection of fine droplets of sub-millimeter or less is difficult.

The present invention focuses on the fact that a liquid pressurized and transported by a liquid feed pump has an electric charge due to flow electrification, and increases the electrostatic capacitance of a droplet ejection apparatus to suppress an increase in the voltage of an ejection port due to flow electrification, thereby suppressing an increase in the coulomb attraction force acting on the electrified droplet. The charged liquid is accelerated and split by an electric field generated by an electrode provided in front of the fine droplet ejection port, and the fine droplets are ejected efficiently. Further, a voltage is applied to the fine droplet ejection port or an electrode at the tip of the ejection port, and the liquid charged by the coulomb force is vibrated to efficiently eject the fine droplets.

According to these methods, fine droplets having a diameter of 50 μm or less can be ejected with a pressure lower than that of the conventional method.

Further, a voltage is applied to a combustion chamber (cylinder, housing, etc.) of the internal combustion engine, and the probability of collision between fuel droplets charged by coulomb attraction and the inner wall of the combustion chamber is increased to promote heat exchange, thereby increasing the vaporization ratio of the fuel droplets. Further, the time required for vaporization is shortened by reducing the diameter of the fuel droplets to about 50 μm.

By these means, the combustion ratio is increased, and an engine having a large output and torque is realized. The achievement of a large combustion ratio results in a reduction in hydrocarbon components in the exhaust gas, and therefore, contributes to the prevention of atmospheric pollution and greenhouse gas effect.

An electric double layer is formed on the surface of the tube due to the presence of electrons permeated to the surface, and a stirling layer adsorbing liquid molecules or ions of dielectric polarization and a gooey-chapmann layer flowing while receiving friction (viscosity) in the fluid are generated. It is considered that, unlike solids, in liquids, the true surface area and apparent surface area are almost the same. The proportion of the liquid molecules of these layers that are occupied by liquid molecules is inversely proportional to the diameter of the tube, the smaller the diameter of the tube the more. Therefore, in order to pass the liquid through the small-diameter tube, a large pressure needs to be applied. When a liquid flows, charges sometimes move beyond the interface, which is called flow charging. It is considered that the electric charges moving in the liquid are gradually shielded by a part of the electrostatic charges due to the dielectric polarization of the liquid molecules, and are introduced into the liquid. Since the flow electrification can be considered as friction in a broad sense, it is considered that the friction force increases as the vertical pressure to the pipe wall increases, and the amount of electric charge moving beyond the interface increases. In a liquid flowing through a small-diameter tube, the amount of charge per unit volume is large, and coulomb attraction acting between the tube wall and the charge in the liquid acts as resistance to the flow and cannot be ignored. In order to eject fine droplets with time control, which is important in practical use, a particularly large pressure is required, and therefore, the wall thickness must be increased. Therefore, the path length of the minute hole also becomes long. Therefore, in the conventional method of pressurizing a liquid by a pump, it is difficult to generate fine droplets as the diameter is smaller. Even when the fine droplets can be generated, the ejection device is large and heavy, and therefore, the manufacturing cost is high. Further, when the size of the injection device is increased, it is necessary to solve secondary problems such as mechanical vibration and noise.

The invention solves the following problem to easily generate micro liquid drops with a small pressure of a liquid supply pump.

(1) Reducing the coulomb attraction force acting between the charges in the liquid and the walls of the injector due to flow electrification.

(2) The charged liquid is accelerated by a voltage applied to the electrodes, and minute liquid droplets are generated with a small pressure.

Further, it is possible to prevent the occurrence of,

(3) the fuel injection device and the combustion chamber which take the flow electrification effect into consideration are utilized, so that large output and torque and high heat efficiency are realized for the power machine.

The inventor finds that: various problems arise in the fuel supply and combustion of the fuel in the internal combustion engine due to the flow electrification. Here, the main cause determining the thermal efficiency of the heat engine will be described, and the problem to be solved will be clarified. To achieve a thermally efficient ideal engine, from the fuel carburetor or the fuel injection device of the indirect injection type and the direct injection type, "1. the whole fuel injected is injected into the cylinder", then "2. the mixture gas of the optimum air-fuel ratio is created", and then "3. the fuel molecules in the mixture gas are completely burned at the optimum timing". Here, the combustion at the optimum timing means combustion in a limited range centered on 90 degrees of the crank angle. It is obvious if no work is done considering the forces applied at the positions of the top dead center and the bottom dead center of the piston.

1. The entire fuel injected is injected into the cylinder

In the fuel carburetor or the indirect injection type injection device, all of the fuel droplets ejected during the time of the intake stroke, that is, during the period in which the intake valve is opened, need to be injected into the cylinder. The ejection of the fuel droplets is controlled by the flow velocity (wind velocity) of the gas in the intake pipe in the case of the carburetor, and by the fuel feed pump in the case of the indirect injection method. However, when coulomb's attraction acts between the fuel liquid charged with different signs due to the flow electrification and the injection ports of these devices, a part of the fuel droplets adheres to the injection ports, and a delay occurs in the injection (see fig. 30), and the fuel droplets are not introduced into the cylinder and remain in the intake pipe (see fig. 37 and 38). Fig. 37 shows the discharged droplets in an insulated state, and shows the vibration start timing (first pulse vibration is 0) (X axis), the discharge order (Y axis), and the magnitude V (Z axis) of the vibration of the pulse vibration included in the 28 fuel injections in fig. 31. Fig. 38 shows droplets arriving at the cylinder in an insulated state, and shows the vibration start timing (first pulse vibration is 0) (X axis), the order of arrival (Y axis), and the magnitude V (Z axis) of the vibration of the pulse vibration included in the 28 fuel injections in fig. 34. It is considered that much of the fuel remaining in the intake pipe is discharged to the exhaust pipe through the cylinder during the period in which the intake valve and the exhaust valve are simultaneously open at the end of the exhaust stroke and at the beginning of the intake stroke (each at about 30 degrees crank angle), and is combusted during the compression stroke (see the compression stroke of fig. 41B, the combustion stroke of fig. 41C, the compression stroke of fig. 19B, and the combustion stroke of fig. 19C). In the direct injection method, this problem does not occur.

2. Mixture gas for creating optimum air-fuel ratio

The stoichiometric air-fuel ratio is estimated stoichiometrically. However, since stoichiometry does not include time as a factor, a practical air-fuel ratio is empirically determined in consideration of output and fuel economy, and a considerably wide range of values including the stoichiometric air-fuel ratio is obtained. The fuel injection device may not operate properly (at the arrow in fig. 31) depending on the rotation speed of the engine, and the ratio of the fuel introduced into the cylinder and the ratio of the fuel combusted in the cylinder may change. For optimization of the reliability and operation of the engine, stable supply of fuel and creation of an optimal fuel mixture gas are important.

3. Complete combustion of fuel molecules at optimum timing

As described above, in order to achieve high thermal efficiency, the fuel is completely combusted within a limited range centered around 90 degrees of the crank angle. The following experimental results show that: the earlier the fuel droplets are injected into the cylinder and the longer the fuel droplets are present there, and the more efficiently the fuel droplets receive heat from the surroundings, the higher the proportion of combustion in the combustion stroke. It is considered that a longer time is required for vaporization of the fuel droplets than has been considered in the past. The experimental results show that combustion is also performed in the compression stroke and the exhaust stroke (see the compression stroke of fig. 19B, the exhaust stroke of fig. 19D, the compression stroke of fig. 43B, and the exhaust step of fig. 43D). The combustion in the exhaust stroke applies a brake to the rise of the piston, and therefore, it becomes a cause of a decrease in the thermal efficiency of the internal combustion engine.

In the present invention, these problems are solved by facilitating the miniaturization of fuel droplets and the vaporization of fuel droplets injected into a cylinder.

Means for solving the problems

(1) One aspect of the droplet ejection apparatus of the present invention is a droplet ejection apparatus including an ejection port for ejecting droplets of a liquid, wherein the ejection port includes one or more ejection holes through which the droplets are ejected, and the ejection port or the droplet ejection apparatus is electrically connected to a conductor so as to suppress an increase in potential due to flow electrification of the droplets, and the electrostatic capacitance of the ejection port or the droplet ejection apparatus is made larger than that in a state where the ejection port or the droplet ejection apparatus is not connected to the conductor.

(2) In the droplet ejection device described in (1), the conductor is an ejection target from which the droplet is ejected from the ejection opening.

(3) In addition, an aspect of the droplet ejection apparatus of the present invention is the droplet ejection apparatus described in (1), further comprising an electrode arranged in front of the ejection opening, wherein the droplet ejected from the ejection opening is accelerated by an electric field formed by applying a voltage to the electrode.

(4) In addition, one aspect of the droplet ejection apparatus of the present invention is the droplet ejection apparatus described in (1), wherein the ejection opening has one or more electrodes for controlling ejection of the liquid inside thereof, and timing and an ejection amount of the liquid pressurized so as to be ejected from the ejection opening are controlled by switching potentials of the electrodes.

(5) In the droplet ejection apparatus according to the aspect of the invention described in (2), a positive voltage is applied to the ejection target to increase a probability of collision between the negatively charged droplets due to flow charging and the ejection target.

(6) In addition, an aspect of the droplet ejection apparatus of the present invention is the droplet ejection apparatus described in (1), including, as the means for ejecting the droplets from the ejection openings: the liquid ejecting apparatus includes a pressure chamber communicating with the ejection port, a vibrating plate for changing a volume of the pressure chamber, an actuator for driving the vibrating plate to vibrate, a controller for controlling driving of the actuator, and a detector for providing information of a vehicle to the controller, wherein the controller controls the actuator based on the information of the detector to vibrate the vibrating plate, and the liquid ejecting apparatus includes a mechanism for ejecting a liquid droplet of a liquid contained in the pressure chamber from the ejection port, wherein a diameter of an ejection hole of the ejection port is 50 μm or less, and a particle diameter of the liquid droplet is 50 μm or less.

Effects of the invention

The droplet discharging device described in (1) can achieve efficient droplet discharging by controlling the influence of the flow electrification.

In the droplet ejection apparatus described in (2), when the object to be ejected is an internal combustion engine, it is possible to suppress an increase in the potential of the droplet ejection apparatus and a decrease in the potential of the internal combustion engine.

In the droplet ejection apparatus described in (3), the fine droplets can be accelerated by the electric field and efficiently ejected from the ejection opening without delay.

In the droplet ejection apparatus described in (4), one or more electrodes are provided inside the ejection opening, and electrons in the pressurized liquid are vibrated by changing the potential thereof, whereby the timing of ejection can be adjusted by the potential to control the ejection amount. The coulomb force acting between the charged liquid and the electrode is changed, and the timing of ejection can be adjusted by the potential to control the ejection amount.

The liquid droplet ejecting apparatus according to (5) can increase the probability of collision with the object to be ejected by causing coulomb attraction to act on the charged minute liquid droplets.

In the droplet jetting apparatus described in (6), the fine fuel droplets having a particle diameter of 50 μm or less can be easily jetted from the plurality of jetting holes having a diameter of 50 μm or less.

Drawings

Fig. 1 is a conceptual diagram illustrating injection ports of an automobile and a fuel injection device of embodiment 1.

Fig. 2 is a conceptual diagram illustrating a cylinder and injection ports of an internal combustion engine of embodiment 1.

Fig. 3 is a conceptual diagram illustrating an automobile, an internal combustion engine, and injection ports of embodiment 1.

Fig. 4A is a conceptual diagram illustrating an electrode facing an ejection port in example 2.

Fig. 4B is a graph showing changes in electrode voltage in the gettering process in example 2.

Fig. 5 is a conceptual diagram illustrating the injection port to which the high-pressure pump is connected in embodiment 3.

Fig. 6 is a conceptual diagram illustrating the operation of the ejection ports in example 3.

Fig. 7A is a conceptual diagram illustrating an internal combustion engine (cylinder, cylinder head) to which a battery is connected according to embodiment 4.

Fig. 7B is a graph showing a change in applied voltage in example 4.

Fig. 8 is a conceptual diagram illustrating a conductor ring provided on a cylinder (cylinder head) according to embodiment 4.

Fig. 9 is a conceptual diagram illustrating a MEMS type fuel injection device of embodiment 5.

Fig. 10 is a conceptual diagram illustrating an intake pipe of the MEMS type fuel injection device according to embodiment 5.

Fig. 11 is a sectional view showing a MEMS type fuel injection device illustrating embodiment 5.

Fig. 12A is a side view illustrating an ejection unit of embodiment 5.

Fig. 12B is a front view of the ejection unit of fig. 12A.

Fig. 13 is a conceptual diagram showing the supply pump pressure and the coulomb attraction force that exert an influence on the fuel liquid of the injection port.

Fig. 14A is a conceptual diagram illustrating collision of droplets in a cylinder (when the incident angle of the droplets is 90 °).

Fig. 14B is a conceptual diagram illustrating collision of droplets in the cylinder (when the incident angle of the droplet is θ).

Fig. 15 is a characteristic diagram illustrating a potential change in an on state in example 1.

Fig. 16 is an enlarged view of the initial impulse of fig. 15.

Fig. 17 is a further enlarged view of fig. 16.

Fig. 18 is a characteristic diagram showing engine sound measurement in the on state.

Fig. 19A is a characteristic diagram (gettering process) showing the power spectrum in fig. 18.

Fig. 19B is a characteristic diagram (compression process) showing the power spectrum in fig. 18.

Fig. 19C is a characteristic diagram (combustion process) showing the power spectrum in fig. 18.

Fig. 19D is a characteristic diagram (exhaust step) showing the power spectrum in fig. 18.

Fig. 20 is a characteristic diagram showing engine sound measurement in the on state.

Fig. 21A is a characteristic diagram (gettering process) showing the power spectrum in fig. 20.

Fig. 21B is a characteristic diagram (compression process) showing the power spectrum in fig. 20.

Fig. 21C is a characteristic diagram (combustion process) showing the power spectrum in fig. 20.

Fig. 21D is a characteristic diagram (exhaust step) showing the power spectrum in fig. 20.

Fig. 22 is a characteristic diagram showing the discharge timing and arrival timing of droplets.

Fig. 23 is a characteristic diagram showing the discharge timing and arrival timing of droplets.

Fig. 24 is a characteristic diagram showing the discharge timing and arrival timing of droplets.

Fig. 25 is a characteristic diagram showing the discharge timing and arrival timing of droplets.

Fig. 26 is a characteristic diagram showing the discharge timing and arrival timing of droplets.

Fig. 27 is a characteristic diagram illustrating example 4 when the start time of the intake stroke is 0.

Fig. 28 is a characteristic diagram showing the results of the dynamic force measurement test.

Fig. 29A is a conceptual diagram (electric vibration chopper) illustrating fig. 5 in detail.

Fig. 29B is a conceptual diagram (ejection port sectional view) illustrating fig. 5 in detail.

Fig. 29C is a conceptual diagram (ejection port front view) illustrating fig. 5 in detail.

Fig. 29D is a conceptual diagram (opening and closing of the valve C and electrode potential) illustrating fig. 5 in detail.

Fig. 30A is a conceptual diagram illustrating a state where the injection port of the fuel liquid adheres in the related art (insulated state).

Fig. 30B is a conceptual diagram illustrating a state where the fuel liquid adheres to the injection ports.

Fig. 31 is a characteristic diagram showing potential measurement of the fuel injection device in the insulated state.

Fig. 32 is an enlarged view of the initial impulse of fig. 31.

Fig. 33 is a further enlarged view of fig. 32.

Fig. 34 is a characteristic diagram showing potential measurement of the engine in the insulated state.

Fig. 35 is an enlarged view of the initial impulse of fig. 34.

Fig. 36 is a further enlarged view of fig. 35.

Fig. 37 is a characteristic diagram showing characteristics of a droplet discharged in an insulated state.

Fig. 38 is a characteristic diagram showing the characteristics of droplets reaching the cylinder in an insulated state.

Fig. 39 is a characteristic diagram showing characteristics of a droplet discharged in the present invention (on state).

Fig. 40 is a characteristic diagram showing engine sound measurement in an insulated state.

Fig. 41A is a characteristic diagram (gettering process) showing the power spectrum in fig. 40.

Fig. 41B is a characteristic diagram (compression process) showing the power spectrum in fig. 40.

Fig. 41C is a characteristic diagram (combustion process) showing the power spectrum in fig. 40.

Fig. 41D is a characteristic diagram (exhaust step) showing the power spectrum in fig. 40.

Fig. 42 is a characteristic diagram showing engine sound measurement in an insulated state.

Fig. 43A is a characteristic diagram (gettering process) showing the power spectrum in fig. 42.

Fig. 43B is a characteristic diagram (compression process) showing the power spectrum in fig. 42.

Fig. 43C is a characteristic diagram (combustion process) showing the power spectrum in fig. 42.

Fig. 43D is a characteristic diagram (exhaust step) showing the power spectrum in fig. 42.

Detailed Description

Hereinafter, embodiments of the invention will be described with reference to examples.

Example 1

In this embodiment, a fuel carburetor or an indirect injection type and direct injection type fuel injection device mounted on a motor vehicle will be described with reference to fig. 1 to 3 and fig. 15 to 17.

In the fuel injection device, the electrostatic capacitance of the injection port is increased, thereby reducing the potential rise due to the flow electrification.

In the fuel injection device, the injection port is electrically conducted to the injection subject, and a potential rise of the injection port and a potential drop of the injection subject are suppressed.

When the pressurized liquid is ejected from the minute ejection holes of the ejection port to generate minute droplets, the liquid charged by the flow charging receives a resistance in a direction opposite to the flow. Therefore, a large pressure needs to be applied to eject the fine droplets. Further, the liquid droplets adhere to the ejection port due to the coulomb attraction force, and a delay occurs in the ejection of the liquid droplets. In order to reduce this effect, the electrostatic capacitance of the ejection device or the ejection port is increased to suppress the potential rise. When the charge amount Q due to flow electrification is fixed in consideration of each ejection of a droplet, the product of the capacitance C and the potential V is a constant (expression (1)).

[ numerical formula 1]

When the ejection device or the ejection port is connected to a conductor having a large surface area in order to increase the electrostatic capacitance (electrostatic capacitance C)₀) At this time, the synthetic electrostatic capacitance becomes C ″ (= C0+ C > C). The relationship between the potential V 'and the potential V' at the time of connection in the above equation (1) holds (equations (2) and (3)).

[ numerical formula 2]

[ numerical formula 3]

Therefore, the ejection device or the ejection port can be connected to the conductor having a large capacitance to suppress an increase in potential.

To increase the electrostatic capacitance C of the droplet discharge device or the discharge port 61₀They are conducted to a conductor (electrostatic capacitance C') having a large surface area 30. At this time, the combined electrostatic capacitance C becomes C = C₀+ C 'is > C'. For example, inIn an automobile, a main body (frame, chassis) 10 (see fig. 1) is considered as a conductor having a large surface area. It is also effective to conduct electricity by coating the surface of the vehicle body with an electrically conductive material, or to conduct electricity with an electrically conductive plastic member.

In order to suppress an increase in the potential of a fuel carburetor or an injection device of an internal combustion engine and a decrease in the potential of the engine, the fuel injection device (or the injection port 61 thereof) and the engine (the cylinder 62 or the like) are electrically conducted (see fig. 2 and 3). From the results of the potential measurement, it was found that the potential variation accompanying the fuel injection was almost eliminated (see fig. 15 to 17, fig. 15 shows the result of measuring the potential of the fuel injection device by bringing the injection device of the motorcycle used in the measurement of fig. 31 into conduction with the engine; the engine speed is 8000 rpm; fig. 16 is an enlarged view of the initial impulse of fig. 15. although a periodic impulse can be recognized, the change in the potential before the impulse can hardly be recognized; fig. 17 is a further enlarged view of fig. 16. before the impulse oscillation, a slight voltage drop (-0.2 to-0.3V or so) was observed.

Example 2

In embodiment 2, a fuel injection device will be described with reference to fig. 4.

The fuel injection device is characterized in that an electrode 64 is provided in front of the injection port 61, and a voltage is applied to the electrode to accelerate negatively charged liquid by an electric field and eject liquid droplets from the injection port.

An electrode 64 is provided forward in the ejection direction of the ejection port 61 of the fine droplet ejection device, and a positive voltage is applied to the electrode 64 to accelerate the negatively charged fine droplets 20 in the movement direction thereof (see fig. 4A in the case of an indirect injection fuel injection device for an internal combustion engine). When the force generated by the electric field and the pressure generated by the liquid feed pump are larger than the coulomb attraction force acting between the negatively charged liquid and the ejection opening 61, the leading end portion of the liquid is split and ejected as liquid droplets. Since the balance of the forces acting on the negatively charged liquid is disrupted by the small pressure of the liquid feed pump, the fine droplets can be ejected at a timing earlier than the case where there is no electric field.

The positive charge generated at the tube wall due to the flow electrification moves to the vicinity of the ejection port together with the negatively charged liquid, and therefore, the number density of the positive charge is considered to be highest at the ejection port. Therefore, it is considered that the fine droplets having a small initial velocity except the ejection opening 61 are adsorbed to the ejection opening surface by the coulomb attraction.

The acceleration caused by the electrodes 64 can reduce this adsorption. This method can reduce the size of the liquid supply pump and reduce the manufacturing cost. Further, vibration and noise generated by the operation of the liquid supply pump and the injection device under high pressure can be reduced. (mixing of noise and decomposition in high-pressure fuel system of a gasoline direct injection engine, J. Borg, A. Watanabe and K. Tokuo, Procedia 48 (2012) 3170-3178). By changing the magnitude and timing of the voltage applied to the electrode 64, the discharge timing of the fine droplets can be adjusted. This method can be used in a wide range of fields requiring the injection of fine droplets, in devices (such as reciprocating engines and rotary engines) using energy generated by injecting and combusting ink or liquid fuel as a power source, and the like.

The fine droplet is ejected by applying a positive voltage to an electrode 64 placed in front of the ejection opening of the fine droplet ejection apparatus to accelerate the negatively charged liquid by an electric field. The shape of the electrode 64 is preferably a ring or a cylinder having good symmetry for allowing the injected fuel droplets to pass through the hollow portion. The electrode 64 is provided at an appropriate position near the ejection opening so as not to contact the liquid droplet and so as not to make the applied voltage large (refer to fig. 4A). The voltage applied to the electrodes 64 depends on the amount of charge in the liquid, the mass and ejection orifice of the droplets, and the distance between the electrodes.

In the case of the experiment disclosed in the following paragraph 0168, which will be described later, the potential of the injection device rises to about 3V in the insulated state between the injection device and the engine. Therefore, the applied voltage is considered to be at most 10V. In the case of the internal combustion engine, a fixed voltage may be always applied, but a pulse voltage may be applied at a time of fuel droplet injection in synchronization with the operation of the fuel pump, in accordance with the crank angle, or by detecting the rise in the potential of the injection port (see fig. 4B).

Example 3

In embodiment 3, a fuel injection device is described with reference to fig. 5, 6, and 29.

The fuel injection device is characterized in that one or more electrodes are provided inside the injection port, electrons in the pressurized liquid are vibrated by changing the potential thereof, and the injection timing is adjusted by the potential to control the injection amount.

The fuel injection device according to this embodiment is different from the injection device shown in fig. 4A in that the electrode 641 is provided in the injection port 61. Then, the storage battery 46 having one end grounded is connected to the electrode 641.

The diameter of the flow path of the fine droplet ejection apparatus is smallest at the ejection opening 61, and further, the number of electrons introduced into the liquid due to flow electrification increases as the distance of the flow becomes longer, and therefore, the electron density in the liquid is largest at the outlet of the ejection opening 61. The charged liquid moves with the positive charge of the tube wall, and therefore, it is considered that the positive charge surface density of the tube wall is maximum in the vicinity of the outlet of the ejection port 61. Therefore, the coulomb attraction force per unit volume acting on the charged liquid is largest near the outlet of the ejection opening 61. A force equilibrium state is instantaneously generated between the coulomb attraction force acting on the charged liquid and the pressure of the pump 41. At this time, when the potential of the ejection opening 61 or the electrode 641 provided at the ejection opening is lowered, the coulomb attraction force becomes small, and therefore, the balance of the forces is broken down, and the fine droplets are discharged. When the potential is further lowered, a coulomb repulsion action is generated, and it is considered that the fine droplets are ejected even when the pressure of the pump 41 is small (see fig. 5 of the drawings in which the direct injection type injection apparatus is used in an internal combustion engine).

As described above, the "unipolar electric vibration chopper" can be used, which cuts open the liquid to be intermittently discharged as liquid droplets when the high-pressure pump 41 vibrates by repeating the rise and fall of the electrode voltage and the alternate action of the coulomb attraction force and the repulsive force in a pressurized state (see fig. 6. fig. 6 shows the movement of the tappet 42 (421 is the top dead center of the tappet and 422 is the bottom dead center of the tappet) in conjunction with the rotation of the cam 43 in fig. 5, the opening and closing operation of the valve a411 of the high-pressure pump 41 and the valve C441 of the reservoir 44, and the relationship between the applied voltage a applied to the electrode 641 and the pulse-like applied voltage B).

Furthermore, the present invention can be used as an "electrical vibration chopper" having high ejection efficiency, which can be used in an ejection device having a long flow path length when the period of variation in potential of each electrode is slightly shifted for a combination of a plurality of electrodes, the amount of liquid to be vibrated is increased, and the amplitude of vibration is increased. Fig. 29 shows an example of a direct injection fuel injection device used in an internal combustion engine. (FIG. 29A shows the structure of the electric vibration chopper 72, FIG. 29B shows the cross section of the injection port 61, FIG. 29C shows the front view of the injection port 61, FIG. 29D shows the relationship between the opening and closing of the valve C441 and the potential of the electrode, the injection port 61 is attached to the attachment hole of the reservoir 44 via the insulating member 451. when the valve C441 is moved upward, the injection port 61 is opened, and when the valve C441 is moved downward, the injection port 61 is closed. the injection port 61 has the electrodes 1 (642) and 2 (643) disposed via the insulating member 452, many injection holes 611 penetrating the electrode 1, the insulating member 452, and the electrode 2 are provided; FIG. 29D shows the state where the variation cycles of the electrode 1 and the electrode 2 are slightly shifted.)

An "electrically vibrating chopper" that accelerates and vibrates charged particles in a solution by a plurality of electrodes is a device having a configuration similar to an electroosmotic pump (electro-osmotic pump). The basic principles of both devices are discussed herein in comparison to the manner of utilization to make the invention more evident both as to its novelty and inventive aspects.

Electroosmosis is a phenomenon discovered by Reuss (F.F. Reuss, Notice sur un novel effect de l' lectricite; galvanique, Meloires de la Soci te; Impp Riale; Riale des Naturatists de Moscou, 1809, 2: 327-.

Now, this phenomenon will be described as follows. When the solution is in contact with the solid surface, ions in the solution are adsorbed to atoms on the surface of the substrate to form a Steren layer, and the ion adsorbed ions are contained in excess on the outside thereofA gooy-chappmann layer of seed ions. Hereinafter, the ions are referred to as positive ions. The adsorbed ions of the Steven layer are immobilized, whereas the ions of the Guey-Chapman layer move toward the electrodes of opposite sign with solvent molecules when an electric field is applied, thus generating a water flow (H-J. Butt, K. Graf and M. kappa., "Physics and Chemistry of Interfaces, 3)^rded., 2013, Wiley-VCH, Linus reineckea kernel, and Shen tail Hao Shi Wan shan).

In this manner, the Navier-Stokes equation (4) is solved

[ numerical formula 4]

And continuity equation (5)

[ numerical formula 5]

To obtain a steady-state flow velocity v of a minute portion flowing in the gouy-Chapman layer. Where η represents the viscosity of the liquid, P represents the pressure applied to the liquid, and ρ_eDenotes the charge density of the positive ions of the gouy-chapmann layer, and E denotes the electric field applied by the electrode plate. In order to make the resistance due to the viscous force obvious as the initial term, the pressure P and the electric field E are made parallel to the x-axis and positive and negative signs are changed in the positive direction, which is different from the document (H-j. Butt, k. Graf and m. kappa). To obtain the flow velocity ν from the expressions (4) and (5), the poisson equation (expression (6)) is used.

[ numerical formula 6]

However, in the liquid, in addition to the ion of the same species as the adsorbed ion, there is also an ion having an opposite sign. In addition to the ions that are not moved by adsorption, the equation of motion of all the ions that are moved by the electric field must be considered. Therefore, the navier-stokes equation (4) for the minute portion of the liquid held by the electrode should be replaced as in equation (7).

[ number formula 7]

Where ρ is_eThe charge density in the liquid, p, representing ions_e ^cRepresenting the charge density of the counter-ion, as a function of position. (7) The direction of the pressure P in the equation (i) is the same as the flow direction, and therefore, is opposite to the direction of the pressure P in the equation (4). At rho_eAnd ρ_e ^cThere is the following relationship therebetween. Where ρ is_e ^adIs the number density of the ions contained in the liquid and in the stirling layer. Rho_e ^adSince it is represented by the formula (8), it can be represented as the formula (9).

[ number formula 8]

[ numerical formula 9]

In general, the pressure P is 0, and therefore the driving force of electroosmotic flow, which is a macroscopic flow, shows the force that charges of opposite sign, equal in number to the number of charges of adsorbed ions, are subjected to in the electric field. The charges of the ions and the liquid molecules move together as a result of charge-dipole interactions, thus creating a macroscopic flow of liquid as a result. However, when the number of ions adsorbed on the substrate is n_adWhen the number of adsorption sites on the surface of the substrate is N, N is required to be satisfied<<N is such that the following expression (10) is satisfied and a stable flow exists.

[ numerical formula 10]

The profile regarding the flow velocity of electroosmotic flow should become small near the interface in the case of equation (4), and at ρ_eThe smallest channel has a minimum value at its central axis. In contrast, in the case of equation (9), it is considered that the flow velocity is maximized at the position of the central axis, and further, when the diameter of the channel is made sufficiently large, the ion concentration is fixed except in the vicinity of the interface, and therefore, the flow velocity is also almost fixed. Electroosmotic flow in capillary using fine particles as a marker and observed with an optical microscope showed a profile predicted from formula (9) (H-J. Butt, K. Graf and M. kappa., "Physics and Chemistry of Interfaces, 3)^rded., 2013, Wiley-VCH, Linus reineckea kernel, and Shen tail Hao Shi Wan shan).

(9) The formula is not only an electroosmotic flow but also a general formula relating to a steady-state flow rate when an electric field is applied to a liquid containing electric charges. For example, when an electric field is applied to a 0-pressurized electrolyte solution in an electrolytic cell, it is considered that the ratio of adsorbed ions is extremely small, ρ_e ^adClose to 0, so no macroscopic flow occurs. In the case where electrons are introduced into the liquid due to the flow electrification, it is also shown that if ρ is caused to be charged_e ^adBeing the number density of electrons in the liquid, the force acting on the electrons in the electric field together with the pressure makes a steady state of flow.

However, the following differences are observed between the case where electrons introduced into the liquid by the flow electrification are accelerated by the electric field and the case of the electroosmotic flow where ions contained in the solution are accelerated.

(1) Pressure applied to the liquid

Introduction of electrons into a liquid due to flow electrification is a case where a large pressure is applied to the liquid. However, in an electroosmotic pump, ions are already present in the solution and, therefore, no pressure needs to be applied to the solution. If any, a small auxiliary pressure (Japanese patent laid-open No. 2004-276224).

(2) Material of flow tube

In the case of flow electrification, a metal tube is used so as to withstand a large pressure, and in the case of an electroosmotic pump, a dielectric (silica glass, an aggregate of oxide fine particles, a polymer such as polycarbonate PC or polymethyl methacrylate PMMA) is used so as to adsorb a specific ion species.

(3) Kind of liquid

It is contemplated that there is no limitation to the liquid generated by the flow electrification. However, in the case of an electroosmotic pump, since it is necessary to dissolve sufficient ions, it is considered that the electroosmotic pump is limited to a polar solvent.

An electroosmotic pump using electroosmosis is a device that causes an ionic current to flow in a solution by an electric field to transport a minute amount of the solution, and is used in the fields of chemical analysis, chemical synthesis, or life science. An electric field is formed by a porous structure such as a flow path or an insulator particle assembly formed on a capillary or a substrate being sandwiched between external electrode pairs or by an electrode pair provided inside the capillary or the like, and ions in an aqueous solution are accelerated by the electric field to transport a liquid. Therefore, since one of the electrodes is at a positive potential and the other is at a negative potential, the magnitude and direction of the ionic current flowing thereby are fixed.

In contrast, the "electrical vibration chopper" is a device that varies the electrode potential, vibrates electrons, and causes pressurized liquid to be ejected from an ejection port as droplets. The delivery of the liquid is generally carried out by means of a high-pressure pump. In the case of the "electrical vibration chopper", when the potential of the electrode fluctuates, the flow of electrons is generated in 2 opposite directions at the same time, and when the potential fluctuates again, the flow of electrons is switched to the opposite direction. Thereby, the liquid vibrates in parallel with the flow direction, and if the amplitude of the vibration is sufficiently large, the liquid is cut and droplets are ejected from the ejection port. The reason why the liquid droplets can be ejected by the unipolar electric vibration chopper is that electrons can be vibrated even by one electrode. When a plurality of electrodes are used, a larger amount of liquid can be vibrated, and therefore, liquid droplets can be ejected efficiently.

When the "unipolar electric vibration chopper" or the "electric vibration chopper" is used for the fuel injection device of the internal combustion engine, the fuel droplets can be made minute, so that the combustion efficiency of the fuel can be improved. When the height of the potential and the period of the potential variation are adjusted, the amount of the fine droplets and the number of times of ejection are changed, and therefore the ejection amount per unit time can be easily controlled. The direct injection type injection device has an excellent characteristic that all of the injected fuel can be fed into the cylinder. However, in order to inject the fuel, a high pressure must be applied. When the "unipolar electric vibration chopper" or the "electric vibration chopper" is used, the pressure of the high-pressure pump can be reduced, so that the pump can be downsized and the cost can be reduced. Further, vibration and noise generated due to the operation of high voltage can be reduced. (mixing of noise and noise in high-pressure fuel system of a gasoline direct injection engine, J. Borg, A. Watanabe and K. Tokuo, Procedia 48 (2012) 3170-3178)

This method can be used in a wide range of fields requiring the injection of fine droplets, for example, a wide range of devices (rotary engines, jet engines, and the like) using energy generated by injecting and combusting ink or liquid fuel as a power source.

An electrode 641 (see fig. 5) is provided in the ejection opening 61 or a part of the ejection opening of the droplet ejection apparatus, and the liquid is sent to the ejection opening 61 in a state where the potential is increased. When the liquid is sucked by the high-pressure pump 41, the valve a411 is opened, and the valves B412 and C441 are closed. When the liquid is sent to the ejection port side, the valve a411 is closed, and the valves B412 and C441 are opened. When the liquid is discharged, the valve C441 may be closed. When considering the effect of flow electrification, it is preferable to make the diameter of the flow path on the upstream side of the valve C441 sufficiently large. In fig. 5 a syringe type pump 41 is shown, but other types of pumps are not excluded.

As an example in the case of using the "electrical vibration chopper" in the fuel droplet injection device of the internal combustion engine, a case of using 2 electrodes is shown in fig. 29. It is necessary to take the thickness of the electrodes 1 (642) and 2 (643) sufficiently so as to withstand a large pressure. By setting the flow path diameter (ejection hole diameter) of the electrode 1 to 100 μm, for example, and the flow path diameter of the electrode 2 to 50 μm, the fuel can be caused to reach the electrode 2 at a pressure smaller than that when the flow path diameters of 2 are all set to 50 μm (643). At this time, the electrode 1 (642) may be thickened to increase mechanical strength. In the case of use as a direct injection type fuel injection device, it is preferable to reduce the space between the electrodes 1 formed when the valve C441 is closed. The potential of the electrode is changed to intermittently eject the fuel as droplets. Fig. 29D also shows an example of opening and closing of the valve C441 and changes in the potentials of the electrodes 1 and 2. Preferably, the time difference d1, d2 between the on and off states of the voltage application to the electrode 1 and the electrode 2 is adjusted according to the channel length. In the case of the injection device used for the two-cylinder engine, pressure is always applied to the liquid in the reservoir 44, and a plurality of valves C441 may be provided in the reservoir 44, and only the valve C441 connected to the cylinder requiring fuel may be opened. The negative electrode of the battery 46 coupled to the electrode is connected to the main body 10. When combined with the fuel injection device of embodiment 2, the applied voltage to the electrode can be reduced.

A rough estimation is shown for an example of an injection device of an internal combustion engine using an "electrical vibration chopper" (fig. 29).

The engine was a 4-stroke 500cc single cylinder gasoline engine operating at 6000 rpm. The fuel injection system is a direct injection system capable of injecting all the fuel into the cylinder. The temperature of the air in the cylinder was made 100 ℃. The molecular weight of the gasoline is 80, and the density is 0.7g/cm³The air-fuel ratio was set to 13: 1. at this time, the amount of gasoline required for 2 engine revolutions was about 0.05cc (5 × 10)¹⁰μm³). The optimal time for gasoline injection is from the end of the intake and the piston passing bottom dead center, assuming the time required for the vaporization of gasoline can be neglected. In this case, since there is no pressure rise in the cylinder due to vaporization of gasoline, the maximum value of the intake amount of air can be achieved. Gasoline is injected during the compression stroke for 2.5 ms. In order to avoid knocking, it is preferable that,the injection timing is made as late as possible, and it is preferable to make the injection timing earlier for vaporization of gasoline droplets. When gasoline is injected into the cylinder, the temperature of the mixture gas in the case of complete vaporization is lower than in the case of incomplete vaporization. This is due to the large latent heat of vaporization. Therefore, it is considered that knocking is unlikely to occur even when the gasoline droplets are miniaturized using the "electric vibration chopper".

The injection port is discussed assuming that gasoline is injected during a period of 1ms immediately before the end of the compression stroke (a timing at which the crank angle changes from bottom dead center to 108 degrees). Assuming that the diameter of the ejection hole of the ejection port is 50 μm, when the electrode voltage of the "electrical vibration chopper" is lowered, a droplet having a depth of 0.5mm from the ejection port surface is ejected, and at this time, the amount of the droplet ejected by 1 ejection from 1 ejection hole is 9.8 × 10⁵μm³. Gasoline was injected at 5X 10 within a period of time of 1ms, assuming that the voltage of the electrodes was changed at 100kHz¹⁰μm³The number of ejection holes required is about 530. When the interval of the ejection holes is made 200 μm, it is sufficient that the diameter of the ejection port having 530 ejection holes is 10 mm. The ejected droplets are elongated, have a diameter of 50 μm and a length of 500 μm, and therefore have a larger specific surface area than spherical droplets of the same volume, and therefore are easily vaporized, and further, since a plurality of aggregation centers can be formed, it is considered that the droplets are immediately broken when ejected.

Example 4

In embodiment 4, a fuel object device will be described with reference to fig. 7 and 8.

The fuel injector device is characterized in that a combustion chamber of the injector includes a cylinder and a piston or a cylinder head, and a positive voltage is applied to the cylinder and the piston or the cylinder head to cause coulomb attraction to the negatively charged fine droplets, thereby increasing the probability of collision with the inner wall of the cylinder, the upper surface of the piston, and the cylinder head.

A positive voltage is applied to a combustion chamber (cylinder or housing, etc.) of the internal combustion engine, so that coulomb attraction acts on negatively charged fuel droplets, the probability of collision between the fuel droplets and the inner wall of the combustion chamber is increased, and vaporization of the fuel droplets is promoted. It is considered that when introduced into the combustion wavefront, the fuel droplets receive heat and vaporize. However, since the velocity of the combustion wave is high, a part of the droplets or the central part of the droplets remains as they are without being burned, and remains as droplets. Therefore, it is an important factor that determines the combustion ratio and the timing of combustion to efficiently obtain the heat (latent heat) required for vaporization of fuel droplets in the combustion chamber in a period of-0.1 milliseconds to-several milliseconds.

The sources of latent heat are the energy transfer resulting from the collisions of the droplets with gas molecules in the air, the collisions with the cylinder inner wall, the piston head surface and the cylinder head surface, and the heat of compression in the radiation and compression strokes from these surfaces. The primary heat source among these may be considered the energy transfer and compression heat generated by the collision. As for the vaporization temperature of the fuel at 1 atmospheric pressure, 30 ℃ to 200 ℃ in the case of gasoline, and 200 ℃ to 350 ℃ in the case of light oil. The gas pressure rises due to compression, and therefore, the actual vaporization temperature is considered to be higher than this.

When the negatively charged fuel droplets collide with the inner wall of the combustion chamber, electric charges move, and the inner wall is negatively charged (see fig. 36). Therefore, as time passes, coulomb repulsion increases, and the probability of collision of the fuel droplet with the inner wall decreases (referring to fig. 14, fig. 14A shows a case where the droplet 20 collides with the inner wall 622 perpendicularly, fig. 14B shows a case where the droplet 20 collides with the inner wall 622 at an incident angle θ due to coulomb repulsion.

When a positive voltage is applied to the combustion chamber, coulomb attraction acts on the negatively charged fuel droplets, the probability of collision of the fuel droplets with the inner wall of the combustion chamber increases, and the adsorption time of the fuel droplets to the inner wall surface becomes long, and therefore, it is considered that the amount of heat received increases.

The effectiveness of the method of raising the potential of the combustion chamber is evident by comparing the intensity of the engine acoustic power of the insulated and conducting states of the injection device and the engine. When conducting, the potential of the engine drops less than in the insulated state, and therefore the potential of the combustion chamber is made slightly higher. The amount of gasoline in the cylinder is smaller in the insulated state than in the conductive state (see fig. 37 and 39, fig. 37 shows the characteristics of the discharged droplets in the insulated state, and fig. 39 shows the characteristics of the discharged droplets in the conductive state). The intensity of the engine acoustic power in the combustion stroke is smaller in the insulated state than in the on state (refer to the combustion stroke of fig. 19C and the combustion stroke of fig. 41C). If it is assumed that the result is only due to the amount of gasoline, the combustion ratio of fuel during combustion is equal, and therefore, it is expected that the amount of gasoline combusted in the exhaust stroke (gasoline remaining without being combusted in the combustion stroke) is larger in the on state, and the intensity of the engine acoustic power is also larger in the on state.

However, as shown in the exhaust step of fig. 19D and the exhaust step of fig. 41D, the intensity of the power in the insulated state is significantly greater than that in the on state, and the result is contrary to the expectation. If it is assumed that there is no difference between the insulated state and the conductive state with respect to the combustion in the exhaust stroke, it is considered that the combustion ratio of the fuel during the combustion increases when the collision probability of the fuel droplets becomes large by making the potential of the combustion chamber high. When the intensity of power in a combustion process is compared between an insulated state and an on state of a motorcycle (KTM DUKE, manufactured by KTM sport cycle AG), the on state is slightly larger and has a slightly higher frequency component. As a result of the power output test, both the output and the torque were approximately-50% larger in the on state than in the insulating state (see fig. 27).

In order to increase the probability of collision of charged fuel droplets in the combustion chamber of an internal combustion engine and to improve the efficiency of heat exchange, the potential of the cylinder, piston or cylinder head is set to be higher than the ground potential. In order to make the potential higher than the ground potential, the cylinder or the like is connected to the positive electrode of the battery, and the negative electrode of the battery is connected to the main body (see fig. 7A and 8, in fig. 7A, the cylinder 62 is connected to the positive electrode of the battery 46 by the lead 30, and the negative electrode of the battery 46 is connected to the main body 10). In the case where the electrostatic capacitance of the cylinder or the like is excessively large in the applied voltage, the electrode plate may be provided in the cylinder, the piston, or the cylinder head, and a positive voltage may be applied to the electrode plate. Fig. 8 shows an example of an annular conductive plate electrode provided on a cylinder or a cylinder head (in fig. 8, an annular conductive ring 641 is provided on a cylinder (cylinder head) 62 via an insulator 451, and the conductive ring 641 is connected to the positive electrode of the battery 46). The start timing and the end timing of the voltage application can be controlled in synchronization with the operation of the fuel pump or by the crank angle (fig. 7B shows an example of the temporal change of the applied voltage).

Example 5

In embodiment 5, a fuel injection device will be described with reference to fig. 9 to 12.

The fuel injection device is characterized by comprising: an actuator that accelerates the liquid fuel by vibration of the vibrating plate; sensors that receive signals from detectors of air flow, engine speed, cooling water temperature, throttle opening, battery voltage, and the like; and a controller for controlling the amount of fuel to be discharged based on information from the sensor, wherein fine fuel droplets having a particle diameter of 50 μm or less are discharged from a plurality of discharge holes having a diameter of 50 μm or less of the discharge port. According to this device, vaporization of the liquid fuel is facilitated, and the thermal efficiency of the engine can be improved.

Combustion of liquid fuels occurs by reacting vaporized fuel molecules with oxygen in the air (water trough fortunate, 3 rd edition, "combustion engineering", published by northson, 2017). Since the vaporization temperature of gasoline is about 80 ℃, it is considered that the gasoline is injected into the cylinder almost as it is as a liquid. Therefore, an increase in the vaporization ratio of fuel droplets in the combustion chamber (cylinder, casing, or the like) is an important factor for improving the thermal efficiency.

In this embodiment, the diameter of the ejection hole of the ejection port in the fuel injection device is set to 50 μm or less, and the size of the fuel droplets to be ejected is set to 50 μm or less, whereby the fuel droplets are easily vaporized. Small droplets are thermodynamically more unstable than larger droplets due to overpressure, are easily vaporized, and, in addition, are easily oxidized, i.e., burned (De Gennes, brocard-virard, Kele, 2 nd edition "physics of surface tension", gilga bookstore, 2017). When the volume of the fuel droplets is decreased, the surface area ratio per unit volume (specific surface area) increases, and the scattering probability with the gas molecules per unit volume increases. Further, the smaller the mass of the fuel droplet, the larger the change in momentum received at the time of collision of the fuel droplet with the gas molecule, and the larger the thermal energy received due to the collision.

Therefore, the smaller the diameter of the droplet, the shorter the time for vaporizing a unit amount of liquid, and the shorter the time for the droplet to disappear. It is also known experimentally that the burning velocity ST and the particle diameter d of the fuel droplets_mIn inverse proportion, an empirical formula as shown in formula (11) is obtained.

[ numerical formula 11]

Here, F/a is a fuel-air ratio, u' is the intensity of the turbulence of the mixed gas (water trough happy, "combustion engineering" 3 rd edition, published by northson, 2017).

When the diameter of the fuel droplets is reduced to reduce the mass, the control of the movement of the charged droplets by the electric field becomes easy.

In order to make the size of fuel droplets discharged from a fuel injection device in an internal combustion engine 50 to 10 μm in diameter, a technology established as MEMS (Micro Electro Mechanical Systems) is used. MEMS is a device composed of an actuator, a sensor, and a controller integrated on a substrate using microfabrication technology. As a structural part of the fuel injection device, as shown in fig. 9: an actuator 53 that injects fuel; a sensor 54 that receives signals from detectors of engine speed, air flow rate, cooling water temperature, throttle opening degree, battery voltage, and the like; and also a controller 51 that controls the actuator based on information from the sensor to control the fuel ejection amount.

As MEMS for fluid ejection, inkjet printer heads have been commercialized. In an inkjet printer head, in order to control the flying arrival position of droplets with high accuracy, electrically conductive ink droplets are accelerated by an electric field, and the position is controlled by an electrode deflection plate. Further, the diameter of the ink droplets is decreased for fine printing, and the ejection frequency per time is increased for high-speed printing (the "ink jet", edited by japan image society, the rattan-yan-repaid, published by tokyo motor university).

In a fuel injection device for an internal combustion engine, an ejection rate per unit time is important as compared with position control of liquid droplets. In order to realize the fuel injection MEMS, it is necessary to solve the problem that it is difficult to achieve both a reduction in the diameter of the fuel droplet and an increase in the amount of fuel discharged per unit time. Therefore, in this embodiment, a MEMS type fuel injection device is proposed in which injection ports of a fuel device are integrated to simultaneously inject many minute fuel droplets. The MEMS type fuel injection device includes a controller 51 that instantaneously changes the fuel supply amount according to the rotation speed of the engine. To increase or decrease the amount of fuel supply, the number of operating injection units 52 or the injection time is adjusted based on information from sensor 54.

Here, the measured 4-stroke engine of 450CC single cylinder was operated at 6000rpm and 20 l/hr of fuel consumption, and the number n of the injection holes of the fuel injection port was estimated under the injection conditions of 50 μm droplet diameter, 1m sec of injection duration, and 200kHz injection frequency. The estimated fuel consumption amount is considered as an upper limit of the consumption amount. The ejection frequency of the droplets was 200kHz achieved by ink jet. The number n of discharge holes is estimated as shown in the formula (12).

[ numerical formula 12]

The actuator 53 of the ejection device is driven by vibrating a vibration plate using a piezoelectric element (piezoelectric element), an ultrasonic vibrator, or an electromagnet. An integrated type fuel injection device having a piezoelectric element actuator is shown in fig. 9 to 12. As shown in fig. 12A, by applying a pulse voltage to the piezoelectric element 531 to deform the piezoelectric element, the diaphragm 532 vibrates, and the volume of the pressure chamber 521 is changed, whereby fuel droplets are ejected from the ejection port 61 of the ejection unit 52 (see fig. 10 and 11) constituting the fuel injection device. By providing a plurality of ejection holes 611 of the ejection port 61 of the ejection unit 52, the number of actuators can be reduced (see fig. 12B). In the ejection port 61 of the ejection unit of the figure, there are 19 ejection holes 611 having a diameter of 50 μm, and therefore, the number of the ejection units is about 530. The amount of the ejected fuel droplets is equal to the amount of deformation of the volume of the pressure chamber 521, and the vibration frequency of the piezoelectric element 531 is the frequency of the pulse voltage. In the case of the indirect injection type, an integrated fuel injection device is provided in the intake pipe 63 as shown in fig. 10. In the case of application to a two-cylinder engine, as shown in fig. 11, all of the injection units 52 may be supplied with fuel by the supply pump 56 and 1 accumulator 44. This is an integrated fuel injection device, and can be applied to any one of the injection devices recited in claims 1 to 3 and 5.

In order to examine the influence of droplet ejection on flow electrification, potential measurement and engine sound measurement were performed on a fuel carburetor or a fuel injection device of an internal combustion engine and an engine. The engines used in the measurement were motorcycle (HOND MEN 450 and KTM 390 DUKE) in which fuel was supplied by a fuel injection device and motorcycle (HONDA KSE 125, manufactured by HONDA industries, ltd.) in which fuel was supplied by a fuel vaporizer. The engine is in electrical communication with the body frame, but the injector is insulated from the carburetor. These engines are all single cylinders, and therefore, the analysis of the potential change and the engine sound change is easy. Even if the number of cylinders is increased, the phenomenon occurring in the 4-stroke from intake to exhaust of the single cylinder engine does not change. In the measurement, an oscilloscope (PicoScope 65444B, manufactured by Pico Technology corporation) was used to connect a passive probe (TA 045, manufactured by Pico Technology corporation) to a fuel vaporizer or a fuel injection device and an engine. A condenser microphone (EMM-6, manufactured by Dayton Audio) was used for the engine sound measurement.

The results and interpretation of the experiment are illustrated in the order of potentiometric and engine acoustic measurements. A method of obtaining the rotation speed from the engine sound is put into practical use, but a method of evaluating the states of intake air, combustion, and exhaust gas from the engine sound is not generally conceivable, and therefore, an analysis method will be described.

Measurement of A potential

Fig. 31 shows the result of the potential measurement of the fuel injection device (HOND MEN 450) in a state insulated from the engine. The engine speed was 6900 rpm. In the figure, 50Hz voltage fluctuation is applied as noise. The impulse period of the graph amplitude 60V, 17.5ms, is the same as the inspiration period. From fig. 32 in which the first impulse of the graph is amplified: the impulse is composed of a plurality of pulse vibrations, and the potential slightly rises before the pulse vibrations. The slope of the potential rise becomes smaller with time, showing a tendency to saturation. As is apparent from fig. 33, which is a further enlarged view of fig. 32, the magnitude of the rise in potential is about 3V.

Fig. 34 to 36 show the results of potential measurement of the engine in a state insulated from the fuel injection device. The engine speed was 7300 rpm. In addition to the 50Hz noise, an impulse of about 3V amplitude is seen, with a period of 16.3ms equal to the period of inspiration. From fig. 35 in which the first impulse of fig. 34 is amplified: the impulse is composed of a plurality of pulse vibrations, and the potential falls before the pulse vibrations. The absolute value of the slope of the potential drop becomes smaller with time, showing a tendency to saturation. As is apparent from fig. 36 further enlarged from fig. 35, the magnitude of the drop in potential is about 0.6V.

The potential change was similarly detected in both the motorcycle (KTM 390 DUKE) and the motorcycle (HONDA KSE 125) using the fuel carburetor. The larger the exhaust amount of the engine and the larger the engine speed, the more significant the magnitude of the potential change.

The period of the impulse is equal to the period of the intake air, and therefore, it is considered that when gasoline is pumped by the fuel feed pump, flow electrification occurs, and the fuel injection device is positively charged. The flow charging is a phenomenon in which a moving liquid is charged with electricity, and gasoline is negatively charged by the flow charging (see non-patent document 2). The presence of multiple potential rises and pulse oscillations in 1 impulse shows that the gasoline droplets are intermittently discharged by 1 inspiration. The gasoline pushed out to the injection port by the pressure of the supply pump is negatively charged, and on the contrary, the injection port of the injection device is positively charged, so that the coulomb attraction acts between the gasoline and the injection port. It is considered that a force equilibrium state is generated between the attraction force and the pressure of the pump. However, when the equilibrium state is broken due to shaking caused by the flow of air in the intake pipe or the like, the fuel is discharged as droplets (refer to fig. 13. fig. 13 shows a state where the fuel liquid 21 pushed out from the injection port 61 by the pressure of the supply pump is negatively charged and the injection port 61 is positively charged. Since this situation is repeated, it is considered that the discharge of the fuel droplets becomes intermittent. It is considered that a large amplitude (about 60V) pulse vibration occurs after the potential rises due to a rapid change in potential.

The potential drop of the engine is considered to be caused by electrons received from the fuel droplets colliding with the inner wall of the cylinder or the upper surface of the piston. When the fuel droplets or the group of fuel droplets decomposed in the middle of the fuel droplets arrive in the cylinder in the discharge order and intermittently collide with the cylinder surface, the change in potential should be intermittent. When the droplets/droplet groups no longer collide with the surface of the cylinder and the supply of electrons is stopped, the potential changes abruptly. It is considered that the pulse vibration having an amplitude of about 4V occurs.

The potential was measured by conducting the fuel injection device (HOND MEN 450) and the engine through a copper wire having a diameter of 2 mm. The results are shown in fig. 15. The engine speed was 8000 rpm. The period of the pulse oscillation with amplitude close to 40V 15.0ms is equal to the period of inspiration. Fig. 16, which is an enlargement of the initial impulse of fig. 15, shows that the impulse is composed of a plurality of pulse vibrations. The potential drops slightly before the pulse oscillations. As shown in fig. 17, which is a further enlarged view of fig. 16, the potential drop is as small as 0.3V or less.

Since the discharge and arrival of droplets of 28 times the intake stroke adopted in fig. 15 to 17 and 31 to 36 were examined, the characteristics thereof will be described using fig. 37 to 39.

Fig. 37 shows the amount of pulse vibration obtained by measuring the potential of the insulated injector shown in fig. 31 to 33. The X-axis represents the start time of the pulse oscillation subsequent to the start time of the first pulse oscillation of 1 pulse as 0, the Y-axis represents the order of these pulse oscillations, and the Z-axis represents the amplitude of the first peak of the pulse oscillation. The starting time of the initial pulse oscillation should be different for each impulse, and therefore, it is not a strict discussion. The amplitude of the first peak of the pulse vibration is an amount used as a reference of the amount of charge charged. Since the start timing of the pulse oscillation is considered as the discharge timing of the fuel droplet, fig. 37 shows a characteristic of the discharge of the fuel droplet.

Many fuel droplets are discharged in a period of about 0.8ms from the start of discharge. Therefore, the discharge time range of the droplets can be considered to be about 0.8 ms. However, there are many droplets discharged in a period of 1ms to 4ms, which shows that the amplitude of the first peak of the pulse oscillation decreases smoothly. Most of the droplets were discharged before the number of discharges was about 10 th, but the distribution of the discharges was expanded to nearly 40 times. The amplitude of the initial peak of the pulse vibration has a wide range of 1V to approximately 60V. When it is considered that the droplet volume is proportional to the charge amount, the range of the distribution showing the volume of the droplet is wide.

Fig. 38 shows the amount of pulse vibration obtained by measuring the potential of the engine in the insulated state shown in fig. 31 to 33. The X-axis, Y-axis and Z-axis represent the same quantities as in fig. 37. Since the start time of the pulse oscillation is considered as the arrival end time at which the fuel/fuel droplet group arrives at the cylinder inner wall, fig. 38 shows the arrival characteristic of the fuel droplets. Most droplets arrive within a period of 0.6ms from the arrival time of the first droplet. Therefore, the arrival time range of the droplet is considered to be about 0.6 ms.

In addition, almost all droplets arrive before the 15 th discharge. The amplitude of the first peak of the pulse oscillation is distributed to approximately 1.5V in the case of fuel droplets arriving within 0.6ms, but the amplitudes of all fuel droplets arriving at later times are 0.5V or less.

When the results of fig. 37 and the results of fig. 38 are compared, although discharged from the ejection device, the liquid droplets having the later discharge timing are not injected into the cylinder. This problem was investigated by combining the results of the engine sound measurement in the "B engine sound measurement" described later.

Fig. 39 shows the amount of pulse oscillation obtained by the potential measurement in the on state of fig. 15 to 17. The X-axis, Y-axis and Z-axis represent the same quantities as in fig. 37. In the amplitude of the pulse vibration, there are two distributions of 15V to 25V and 5V or less. Most of the droplets are discharged within 0.5 ms. It is considered that the reason why the amplitude of the pulse at the later discharge timing is as small as 5V or less is that the volume of the droplet becomes small. The fuel droplets distributed relatively densely in the range of 15V to 25V exist in the range before the number of discharge times is 15.

When it is considered that the charge amount of the fuel droplets is determined by the pressure applied to the liquid in the fuel injection device and the area of the wall of the flow path, the charge amounts in the insulating state and the conducting state should be equal. However, the maximum value of the pulse vibration in the on state is as small as about 40V (fig. 15) and smaller than the maximum value of 60V in the insulating state (fig. 31). This is considered to be because the electrostatic capacitance of the injection port (injection device) is increased by conduction with the engine, and therefore, the increase in the potential of the injection device or the injection port is reduced, and the coulomb attraction acting on the charged gasoline liquid is reduced, and as a result, the liquid droplets are ejected when the applied pressure is small.

When the results of fig. 39 are compared with the results of fig. 37, the time until the droplet is discharged is shorter and the range of the distribution of the volumes of the droplets is narrower when compared with the insulating state. Also considered according to the results are: in the on state, the coulomb attraction force acting on the droplet is small, and the droplet is ejected when the applied pressure is small.

B Engine Sound measurement

An engine is considered as a device that converts a part of energy generated by combustion of fuel into sound energy. When the engine speed is fixed, energy is generated in the combustion stroke, the stroke advances, and the intake valve and the exhaust valve are periodically opened and closed, and the structure as a vibrating tube and the flow of gas change, so the engine sound periodically changes. If it is assumed that the magnitude of sound energy is proportional to the energy generated by combustion of fuel, the states of intake, combustion, and exhaust can be evaluated by measuring the engine sound.

The energy (energy density) < E > of the sound of 1 cycle per unit volume is expressed as the expression (13), which is proportional to the square of the frequency f and the square of the amplitude A.

[ numerical formula 13]

Here, ρ is the density of the medium through which sound propagates. The intensity I of sound is the energy propagated through a unit area per unit time, and hence becomes the expression (14).

[ numerical formula 14]

Here, ν is the speed of sound in the medium. The sound pressure P is detected by the microphone and output as a voltage signal. The relationship of the expression (15) holds for the sound pressure and the intensity I of the sound.

[ numerical formula 15]

When a waveform (voltage signal) x (t) obtained by measurement is fourier-transformed, an amplitude spectrum x (f) is obtained as a fourier coefficient (expression (16)).

[ number formula 16]

When the waveform x (t) is squared and integrated, energy is obtained, and the square of the amplitude spectrum is the energy according to the peltier equation ((17)).

[ number formula 17]

Since the waveform obtained by measurement is a discrete numerical string, the waveform x of the N-point sample in the analysis section_nPerforming discrete Fourier transform to obtain discrete Fourier coefficient X_k(formula (18)).

[ numerical formula 18]

Then, a spectrum p (k) of the energy per unit time, i.e., the power is obtained as shown in expression (19).

[ number formula 19]

The engine sound measurement and the potential measurement are performed simultaneously. At this time, since the distance between the microphone and the engine is set to 30cm, there is a delay of about 1ms in the signal of the engine sound measurement with respect to the signal of the potential measurement. The number of revolutions of the engine obtained from the impulse period of the potential measurement is 5000 to 6000rpm (the period of 4 strokes of intake, compression, combustion and exhaust is 24 to 20 ms).

The engine sound analysis is performed as follows. Assuming that the time ranges of the strokes are equal, the 1 cycle amount is divided into 4 segments for 4 cycle amounts of 4 strokes to obtain 16 small intervals. When a, b, c and d are adopted in the order of 4 divisions and the periods are marked with a corner mark number of 1-4 until 4 periods, the suction stroke is a₁、a₂、a₃、a₄The compression stroke is b₁、b₂、b₃、b₄Is detected. The same applies to the combustion stroke and the exhaust stroke. In the fitting of the spectrum analysis, 4 small intervals of the angle marks 1 to 4 of each stroke are used as continuous intervals, and the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke are performed simultaneously. The fitting of 4 cycles is performed to increase the analysis interval length and increase the frequency resolution.

Since the start timing of the intake stroke is unclear, it is assumed that, as described below,

(1) starting the suction stroke (suction valve open) before the moment of expulsion of the gasoline droplets

(2) The starting time of the intake stroke (the time when the intake valve is opened) in the insulated state and the conducting state are equal

Further, the fitting start timing was changed every 0.05ms, and the fitting start timing satisfying the following condition was defined as the intake stroke start timing.

(1) The suction and exhaust valves are closed and no new energy is generated, thus minimizing the power of the compression stroke.

(2) If it is assumed that there is a change in the frequency component, it occurs at the change boundary of each stroke.

Graphs showing assay data and results of the analysis are shown. An engine acoustic spectrum (fig. 40) showing an insulation state between a fuel injection device and an engine of a motorcycle (HOND MEN 450) and a frequency dependence of engine acoustic power are shown in the order of an intake stroke (fig. 41A), a compression stroke (fig. 41B), a combustion stroke (fig. 41C) and an exhaust stroke (fig. 41D). Fig. 40 shows 4 cycles and 16 small sections obtained by dividing the 4 cycles into 4 segments (in fig. 40, the horizontal lines on the waveform show the time of (1) the intake stroke, (2) the compression stroke, (3) the combustion stroke, and (4) the exhaust stroke in descending order from the top).

Fig. 18 and 19 also show the results of the on states of the fuel injection device and the engine. Fig. 18 shows an engine sound spectrum in a conducting state between a fuel injection device and an engine of a motorcycle (HOND MEN 450) (in fig. 18, horizontal lines on a waveform show the time of (1) an intake stroke, (2) a compression stroke, (3) a combustion stroke, and (4) an exhaust stroke in order from high to low, and spectral analysis is performed for 4 times of these 4 strokes). The frequency dependence of the engine acoustic power is shown in the intake stroke of fig. 19A, the compression stroke of fig. 19B, the combustion stroke of fig. 19C, and the exhaust stroke of fig. 19D.

Fig. 42 and 43, and fig. 20 and 21 show the same for a motorcycle (KTM 390 DUKE).

Fig. 42 shows an engine sound spectrum in an insulated state between a fuel injection device and an engine of a motorcycle (KTM 390 DUKE), and frequency dependence of engine sound power is shown in an intake stroke of fig. 43A, a compression stroke of fig. 43B, a combustion stroke of fig. 43C, and an exhaust stroke of fig. 43D. (in FIG. 42, the horizontal lines on the waveform show the time of (1) the intake stroke, (2) the compression stroke, (3) the combustion stroke, and (4) the exhaust stroke in order from the high to the low; the spectrum analysis is performed for 4 times of these 4 strokes.)

Fig. 20 shows an engine sound spectrum in a conduction state between a fuel injection device and an engine of a motorcycle (KTM 390 DUKE), and frequency dependence of engine sound power is shown in an intake stroke of fig. 21A, a compression stroke of fig. 21B, a combustion stroke of fig. 21C, and an exhaust stroke of fig. 21D. (in FIG. 20, the horizontal line above the waveform shows the time of (1) the intake stroke, (2) the compression stroke, (3) the combustion stroke, and (4) the exhaust stroke in order from the high to the low; the spectrum analysis is performed for 4 times of these 4 strokes.)

Fig. 27 shows the start of the intake stroke in summary.

When these results are compared, the following are known about the motorcycle (HOND MEN 450 and KTM 390 DUKE) with respect to the insulation state and the conduction state.

(1) The start of the intake stroke (opening of the intake valve) is almost the same phase in the engine sound spectrum.

(2) The difference in the frequency distribution of the intake stroke is small under the same engine condition.

It can be said that the conditions of the initial assumption are confirmed to be correct.

The results of comparing the insulation state and the conduction state of the motorcycle (HOND MEN 450) are listed.

(a) The time difference between the start time of the intake stroke determined from the engine sound and the time of the pulse vibration indicating the first droplet discharge determined from the potential measurement was 0.3 ms in the insulated state and-0.1 ms in the conductive state. The detection of the engine sound is delayed by about 1ms from the electrical signal, so the actual time difference is about 1.3ms and 0.9ms, respectively.

(b) In the compression stroke, the power of the insulation state is greater than that of the conduction state;

(c) during the combustion stroke, the power in the on state is significantly greater than in the off state;

(d) during the exhaust stroke, the power in the isolated state is significantly greater than in the on state;

when the results of the potential difference measurement are considered, these results are explained as follows.

(1) It is considered that the reason why the power of the compression stroke is larger in the insulated state than in the on state is that gasoline remains more in the intake pipe than in the on state, and when the intake valve and the exhaust valve are simultaneously opened, the gasoline passes through the cylinder to reach the exhaust system and is burned during the compression stroke.

(2) It is considered that the power of the combustion stroke is larger and the power of the exhaust stroke is smaller in the on state than in the insulating state because the amount of gasoline introduced into the cylinder is larger and the combustion ratio is higher in the on state.

(3) It is considered that the reason why the power of the exhaust stroke is larger in the insulated state than in the on state is that the amount of gasoline remaining without being combusted in the combustion stroke is larger in the insulated state than in the on state, and the remaining gasoline is combusted in the cylinder or the exhaust pipe in the exhaust stroke.

Therefore, it can be said that making the delay of the discharge timing of the fuel droplets small, making the proportion of the fuel introduced into the cylinder large and promoting vaporization of the fuel droplets in the cylinder, making the combustion proportion large are decisive main causes for improving the thermal efficiency of the engine that supplies fuel by the indirect injection method to achieve a large output and torque.

Fig. 28 shows the results of a power measurement test performed on a motorcycle (KTM 390 DUKE) using a power measurement test apparatus (Dynojet, 250ix, manufactured by Dynojet corporation) in which the output and the torque were compared with respect to the insulated state and the conductive state. The engine speed was 6000rpm in both the on state and the off state. In the on state, both output and torque are increased by about 50% over the insulated state. When comparing the engine acoustic power of the combustion stroke in the insulated state and the on state, it appears that the on state is slightly larger than the insulated state (the intake stroke of fig. 21A and 43A) except for the 150Hz component.

C droplet discharge time/arrival time and crank angle

In order to compare the start timing of the intake stroke and the discharge timing/arrival timing of the droplets, a graph of the potential measurement and a graph of the waveform of the engine sound are shown in fig. 22 to 24 in a superimposed manner (fig. 22 shows the change in the potential and the engine sound of the fuel injection device (injector) in the state of insulation between the fuel injection device and the engine; fig. 23 shows the change in the potential and the engine sound of the engine in the state of insulation between the fuel injection device and the engine; fig. 24 shows the change in the potential and the engine sound of the fuel injection device in the state of conduction between the fuel injection device and the engine; the engine sound is measured with a delay of 1 ms). The dashed line in the figure shows the intake stroke start time obtained from the engine sound data by the procedure described in the aforementioned "B engine sound measurement".

In the graph of fig. 22 showing the injector potential in the insulated state, a group of straight lines that are perpendicular from 29ms to 29.5ms is seen. This is an impulse showing the discharge of a droplet. A plurality of vertical straight line groups seen in fig. 23 showing the potential change of the engine are impulses showing the end of arrival of the droplet. The start timing of the intake stroke is shown by a broken line between vertical straight lines seen in fig. 24 showing potential changes when the injector and the engine are turned on. In the 3 patterns, a thick line showing an impulse of a potential and a thin line showing a waveform in which the impulse is applied to the engine sound as noise are both overlapped. It is known that the time difference between the start timing of the intake stroke and the discharge of the liquid droplets is reduced by conducting the injector and the engine.

The results are shown in summary in fig. 27. For reference, the results of KTM 390 DUKE are also shown together. Fig. 27 also records a value for correcting the delay (1 ms) of sound detection. The discharge/arrival times in the table are the discharge time range and the arrival time range of the liquid droplets arriving at the cylinder found from the graphs of fig. 37 to 39. The rotation speeds of the engines differ for each measurement, and therefore cannot be simply compared with time, and the results of comparison by the angle of the crank are shown in fig. 25 and 26 (in fig. 25 and 26, the discharge start time of the insulating liquid droplet is a, the end time is a ', the arrival start time of the insulating liquid droplet is b, the end time is b ', and the discharge start time of the conducting liquid droplet is c, and the end time is c ').

Fig. 25 is a graph in which the time at which the piston is at the top dead center is considered as the start time of the intake stroke. If the intake valve and the exhaust valve are both opened within 30 degrees before and after the top dead center position, the exhaust valve is closed at the start of the discharge of fuel droplets, and the discharged fuel droplets are not exhausted through the cylinder, regardless of whether in the insulated state or in the conductive state. At the end of the discharge time, the displacement speed (wind speed) of the piston becomes almost maximum. It is considered that the reason why the droplets discharged later do not reach the cylinder is that the wind speed becomes small halfway.

Fig. 26 is a graph in which the start timing of the intake stroke is set to a timing at which the piston is 30 degrees before the top dead center. The discharge of the fuel droplets in the insulated state and the conducted state is started before the exhaust valve is closed. The end time of the droplet discharge time in the on state is far before the time when the displacement speed (wind speed) of the piston becomes maximum, and therefore, it is considered that most of the droplets reach the cylinder.

It is worth noting that in 2 examples where the crank angle at the moment the suction valve is opened is different, the displacement of the piston is not half in the last discharge moment when the droplet can reach the cylinder. This is considered because the air expands in volume due to the heat inside the cylinder and vaporizes a part of the gasoline, and therefore, the decrease in pressure inside the cylinder caused by the displacement of the piston toward the bottom dead center is cancelled out, and the wind speed in the intake pipe approaches 0.

D summary of the invention

It has been stated that the time required for vaporization of the fuel droplets is longer than hitherto considered. It is considered that the time required for vaporization becomes long because electrons are introduced into the fuel droplets due to the flow electrification. The fuel molecules are dielectrically polarized by electrons, the intermolecular force becomes large, and the cohesive force of the droplets increases (j.n. israel achieville, 2 nd edition of intermolecular and surface forces, 1996, toward bookstores). Therefore, it is considered that a larger amount of heat is required to vaporize the charged fuel droplets than in the case of being electrically neutral.

Further, it is considered that when the fuel droplets are charged, the probability of collision with the cylinder inner wall, the piston surface, and the cylinder head inner surface is reduced, and therefore the amount of heat received by the collision is reduced. When the charged fuel droplets enter the cylinder and a part thereof collides with the surrounding wall, the cylinder or the like receives electrons, and thus the potential is lowered. Therefore, the charged fuel droplets are subjected to coulomb repulsion from the cylinder inner wall or the piston upper surface. Even if the magnitude of the repulsive force is small, the fuel droplets cannot collide with the cylinder inner wall or the piston upper surface when the incident angle is sufficiently large (see fig. 14). Therefore, compared to the case where the coulomb repulsion does not act, the collision probability of the fuel droplets is reduced, and the time required to obtain the heat required for vaporization becomes longer.

It is considered that the reason why the power of the engine sound becomes large when the injector and the engine are brought into conduction is that the amount of fuel injected into the cylinder increases, the time for receiving heat in the cylinder becomes long, and the potential of the inner wall of the cylinder or the like is suppressed from decreasing, the extent of the decrease in the collision probability becomes small, and the amount of heat received by the collision becomes larger than the insulating state.

In the direct injection type fuel injection device, all of the injected fuel is introduced into the cylinder and does not leak to the outside. However, it is considered that the speed of the air flow in the cylinder is smaller than that of the air flow in the intake pipe of the indirect injection system, and therefore, it is difficult to miniaturize and vaporize the fuel droplets. Therefore, in the direct injection type fuel injection device, particularly, the fuel droplets are strongly required to be miniaturized at the time of injection. In order to miniaturize the fuel droplets, it is necessary to inject the fuel liquid from a small-diameter injection port by applying a large pressure to the fuel liquid by a high-pressure pump. As a result, the direct injection method has a more significant effect of flow electrification than the indirect injection method.

The embodiments of the present invention have been described above with reference to examples.

An object of the present invention is to provide a highly efficient droplet ejection apparatus in which the influence of flow electrification is controlled, but the droplet ejection apparatus in which the influence of flow electrification is controlled includes, for example, the structures described in the above embodiments in addition to the inventions described in claims 1 to 6.

As an example thereof, there are the following droplet ejection devices and the like:

a droplet ejection apparatus includes an ejection port, an electrode provided in front of the ejection port, and an electric field for accelerating a negatively charged liquid by applying a voltage to the electrode to eject a fine droplet from the ejection port;

a droplet ejection apparatus is provided with an ejection port in which one or more electrodes are provided, electrons in a pressurized liquid are vibrated by changing the potential of the electrodes, and the timing of ejection is adjusted by the potential to control the ejection amount;

a droplet ejection apparatus includes an ejection port for applying a positive voltage to an ejection target and increasing a probability of collision with the ejection target by causing Coulomb attraction to act on negatively charged fine droplets;

a droplet ejection apparatus is provided with ejection ports, and further provided with an actuator that accelerates the liquid by vibration of a vibrating plate to facilitate vaporization of the liquid and improve thermal efficiency of an ejection target, a sensor that receives signals from detectors of an air flow rate, an engine rotation speed, a cooling water temperature, a throttle opening degree, a battery voltage, and the like, and a controller that controls an ejection amount of the liquid based on information from the sensor and ejects minute fuel droplets having a particle diameter of 50 [ mu ] m or less from ejection holes of a plurality of ejection ports having a diameter of 50 [ mu ] m or less.

These droplet ejection apparatuses can eject fine droplets efficiently.

Description of reference numerals

10 main body

20 liquid droplet

21 fuel liquid

30 wire

41 high-pressure pump

411 valve A

412 valve B

42 tappet

421 top dead center

422 bottom dead center

43 cam

44 reservoir

441 valve C

45 insulation

452 insulating member

46 accumulator

51 controller

52 jet unit

521 pressure chamber

53 actuator

531 piezoelectric element

532 vibration plate

54 sensor

56 oil supply pump

561 oil tank

61 jet orifice

611 spray hole

62 air cylinder

621 cylinder head

622 inner wall

63 air suction pipe

64 electrode

641 conductor ring

642 electrode 1

643 electrode 2

70 fuel injection device

701 MEMS type fuel injection device

72 electrically vibrating the chopper.