Microdroplet injection device for internal combustion engines

Abstract

To provide a high-efficient fluid injection device used in an internal combustion engine, an ink-jet printer, etc. and controlling effect of flow electrification.SOLUTION: Coulomb force applied to electrically charged fuel drops is controlled, and vaporization of fuel drops injected into a cylinder is facilitated. An electrostatic capacitance of a fuel vaporizer or fuel injector is increased. An electric field by an electrode installed in front of a fuel injection port accelerates and divides an electrically charged fuel to efficiently inject fuel drops. Voltage is applied to an injection port or injection port tip to efficiently inject electrically charged fuel drops with coulomb force. Voltage is applied to a combustion chamber to increase, with coulomb attraction force, a probability of collisions between electrically charged fuel drops and an inner wall of the combustion chamber to promote heat exchange so as to increase a vaporization ratio of the fuel drops. Realizing a large combustion ratio reduces a constituent of a hydrocarbon system in exhaust gas, so as to contribute to prevention of air pollution and greenhouse gas effect.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention provides Internal combustion engine This relates to a device that sprays liquid used in the above in the form of minute droplets. [Background technology]

[0002] One example of a technology for improving the thermal efficiency of internal combustion engines (ICEs) is an injection device that injects liquid into a target in the form of minute droplets by optimizing fuel combustion. When liquid passes through an injection device or carburetor, flow electrification occurs. The injection device or carburetor and the liquid are charged positively and negatively (or negatively and positively depending on the combination of materials), respectively. This Coulomb attraction acts between the droplets and the injection device. The Coulomb attraction due to flow electrification is thought to be the main reason why smaller droplets require greater pressure to eject. The technology of the present invention contributes to surface finishing of coatings and high-density inkjet printing. Furthermore, in internal combustion engines, the purpose of this technology is to provide a technology that overcomes the reduced fuel combustion rate caused by delayed fuel droplet release and vaporization due to Coulomb attraction, thereby achieving high thermal efficiency, high power, and torque, while improving the combustion rate and reducing the hydrocarbon content in exhaust gases.

[0003] This invention relates to a technology for generating microdroplets for surface modification, the manufacture of ultrathin multilayer three-dimensional structures, and for improving thermal efficiency by optimizing fuel combustion in internal combustion engines. A large pressure is required to generate microdroplets by ejecting a liquid from a small nozzle. Since the specific surface area of ​​a liquid (the ratio of surface area per volume or mass) increases in inverse proportion to the nozzle diameter, the effect of flow electrification occurring at the interface between a solid surface and a liquid becomes prominent in the generation of microdroplets. A large pressure must be applied to the liquid to eject it against the charge (which may be negative or positive depending on the combination of substances) incorporated into the liquid by flow electrification and the Coulomb attractive force acting on the dielectrically polarized liquid molecules acting between the microdroplet ejection device or its nozzle. The technology of this invention, which electrically controls charged liquid and microdroplets, allows microdroplets to be ejected from a nozzle with less pressure than conventional technology. This technology can be applied to surface modification of coatings and the construction of ultra-thin multilayer three-dimensional structures using inkjet printing. Furthermore, when applied to internal combustion engines, the high combustion rate of micro fuel droplets achieves high thermal efficiency, high power output, and torque, and can reduce the proportion of hydrocarbon components in exhaust gases.

[0004] If we could control the injection time and volume of droplets with a diameter of, say, approximately 10 μm, it is likely that innovation clusters would emerge in various fields. The use of tiny droplets would enable improved paint thickness control and decorativeness, as well as higher dot density and information density in printing. It would also accelerate the development of organic semiconductor integrated circuits, ultrathin multilayer film substrates, and large-area integrated circuits using inkjet printers. Furthermore, innovations in internal combustion engines are possible. Internal combustion engines are one of the most important power sources for transportation such as automobiles and other industrial applications, and represent a highly developed technological field. The thermal efficiency of internal combustion engines is low compared to the efficiency of other heat engines, at 20% to 30% for gasoline engines and 30% to 40% for diesel engines, leaving significant room for improvement. The formation of the air-fuel mixture, air intake, and combustion, which determine thermal efficiency, depend on the timing of air intake, ignition, compression, and exhaust, which are controlled mechanically or electronically. The time required for these processes is short, ranging from a few hundred microseconds to tens of milliseconds, and conditions such as temperature, pressure, and mixture change with changes in engine speed. For this reason, many aspects of the physical and chemical phenomena involved in these processes remain unclear (see Non-Patent Document 1). Recently, the inventors measured the potential differences between the ground potential and the potential of the fuel carburetor, fuel injector, and engine during operation and discovered that these potential differences fluctuate periodically (see Figures 33 to 38). Figure 33 shows the results of potential measurements of a fuel injector mounted on a conventional motorcycle (HONDA MEN 450) at an engine speed of 6,900 rpm. The injector is insulated from the target object, the object of fuel injection. Two arrows in the figure indicate failed fuel injections. Figure 34 is an enlarged view of the first impulse shown in Figure 33. This shows that one impulse consists of multiple voltage rises and pulse oscillations. Figure 35 is a further enlargement of Figure 34, showing that there is a potential rise of up to 3 V prior to the pulse oscillation. Figure 36 shows the results of potential measurements of the internal combustion engine mounted on the conventional motorcycle shown in Figure 33 at an engine speed of 7,300 rpm. The engine is insulated from the injector. As shown in the figure, periodic impulses can be seen riding on the voltage fluctuation noise. Figure 37 is an enlarged view of the first impulse shown in Figure 36. This shows that one impulse consists of multiple voltage drops and pulse oscillations. Figure 38 is a further enlargement of Figure 37, showing that there is a potential drop of up to 0.6 V prior to the pulse oscillation.

[0005] The fluctuation in the potential difference is due to flow electrification, in which negative charges (electrons) on the walls of the fuel carburetor and fuel injection device are absorbed into the gasoline. Flow electrification can be considered a friction phenomenon in the broad sense. When two different types of dielectrics are rubbed together, static electricity is generated, and the phenomenon of each becoming positively and negatively charged has been known since the time of ancient Greece. Two charged objects are not limited to dielectrics, but can also occur with conductors or fluids. Frictional force is proportional to the weight of the objects. Furthermore, 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. When a liquid and Since the apparent contact area and the actual contact area at the interface of a solid are thought to be almost equal, it is thought that the amount of charge per unit volume of a fluid due to flow electrification increases with the contact area of ​​the fluid. Flow electrification has been known for a long time (see Non-Patent Document 2), and it has been reported that discharges caused by high electric fields generated by accumulated charges can cause explosions in oil pipelines, oil storage tanks, and other places. For this reason, research on flow electrification has been actively conducted (T. Paillat, G. Touchard and Y. Bertrand, Sensor, 2012, 12, 14315-14326). However, the physical and chemical mechanisms by which flow electrification occurs and the manner in which it manifests have not yet been elucidated, and further progress in quantitative research is needed. The polarity of the charge of the charged droplets is considered to be determined by a combination with the material of the device. In this specification, for ease of understanding, the polarity of the droplets will be described as negative, but this does not exclude the case where the polarity is positive. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Advanced engine technology, Heintz Heisler, 2009, Butterworth-Heinemann [Non-patent document 2] Electrostatics in Petroleum Industry: The Prevention of Explosion Hazards; A. Klinkerberg and JL van der Minne, 1958, Elsevier, Amsterdam, The Netherlands, Summary of the Invention [Problem to be solved by the invention]

[0007] When liquid is sprayed from the spray device, flow electrification occurs as it passes through, and Coulomb force acts between the charged liquid droplets and the electrostatically charged nozzle, causing problems such as delayed or insufficient droplet release. The present invention has been made in view of the above circumstances, and provides an efficient microdroplet jetting device that controls the influence of flow electrification. In an internal combustion engine using a micro-droplet injection device, when Coulomb attractive force acts between the fuel liquid, which has an opposite charge caused by flow electrification, and the injection port, a delay occurs in the release of the fuel droplets, and some of the fuel droplets are not taken into the cylinder. In addition, the results of engine noise measurement and power measurement tests conducted by the inventors indicate that efficient vaporization of fuel droplets in the cylinder is important to achieve a high combustion rate and high power output. Based on these findings, the inventors have developed a fuel injection device which is an example of the fluid injection device and which controls the Coulomb force acting on the fuel liquid and droplets ejected from a fuel carburetor or an indirect injection or direct injection fuel injection device, and further developed a fuel injection device which efficiently injects fine fuel droplets which are easily vaporized in a short period of time and controls the injection amount in response to the engine speed.

[0008] The method of generating droplets by applying pressure to a liquid to intermittently eject it from a nozzle is extremely important in practice because it is simple and easy to control. Reducing the nozzle diameter to eject small droplets increases the contact area of ​​the liquid inversely proportional to the nozzle diameter, resulting in increased friction (fluid friction) drag and requiring greater pressure. Furthermore, the Coulomb attractive force due to flow electrification acts as a drag, making it difficult to eject droplets of submillimeter size or smaller. This invention focuses on the fact that liquids transported under pressure by a liquid feed pump acquire an electric charge due to flow electrification. By increasing the capacitance of the microdroplet ejection device, we suppress the increase in the voltage at the nozzle due to flow electrification and the increase in the Coulomb attractive force acting on the charged microdroplets. Furthermore, the charged liquid is accelerated and split in an electric field by an electrode installed in front of the microdroplet ejection nozzle, allowing for efficient ejection of microdroplets. Furthermore, applying voltage to the microdroplet ejection nozzle or to an electrode at the nozzle tip vibrates the charged liquid due to Coulomb attractive force, resulting in efficient ejection of microdroplets. These methods make it possible to eject minute droplets with a diameter of 50 μm or less at lower pressure than previously possible. Furthermore, by applying a voltage to the combustion chamber (cylinder, housing, etc.) of an internal combustion engine, the probability of collision between the charged fuel droplets and the combustion chamber wall, which is caused by Coulomb attraction, is increased, promoting heat exchange and increasing the vaporization rate of the fuel droplets. Furthermore, by reducing the diameter of the fuel droplets to around 50 μm, the time required for vaporization is shortened. These measures increase the combustion rate, resulting in an engine with high power and torque. Achieving a high combustion rate reduces the hydrocarbon components in exhaust gases, thereby contributing to the prevention of air pollution and greenhouse gas effects.

[0009] The presence of electrons seeping out to the surface creates an electric double layer on the surface of the tube, forming a Stern layer where dielectrically polarized liquid molecules and ions are adsorbed, and a Gouy-Chapman layer where fluid flows due to friction (viscosity). Unlike solids, the true and apparent surface areas of liquids can be considered almost identical. The proportion of liquid molecules in these layers increases as the diameter of the tube decreases, inversely proportional to the diameter of the tube. Therefore, a large pressure is required to move liquid through a small-diameter tube. As liquid flows, electric charges can move across the interface, a phenomenon known as streaming electrification. Charges that move into the liquid are gradually partially electrostatically shielded by the dielectric polarization of the liquid molecules and are absorbed into the liquid. Since streaming electrification can be considered friction in a broad sense, the greater the normal pressure on the tube wall, the greater the frictional force, and the greater the amount of charge that moves across the interface. When liquid flows through a small-diameter tube, the amount of charge per unit volume increases, and the Coulomb attraction between the tube wall and the charges in the liquid cannot be ignored as a drag on the flow. For the time-controlled ejection of minute droplets, which is important in practical applications, particularly high pressure is required, necessitating thick vessel walls. This in turn increases the path length of the minute holes. Therefore, with conventional methods of pressurizing liquid using pumps, it becomes increasingly difficult to generate minute droplets as the diameter decreases. Even if minute droplets can be generated, the injection device becomes large and heavy, resulting in high manufacturing costs. Furthermore, increasing the size of the injection device necessitates the need to address secondary problems such as mechanical vibration and noise.

[0010] The present invention solves the following problems in order to easily generate minute droplets with a small pressure of a liquid feed pump. (1) Reduce the Coulomb attractive force acting between the charge in the liquid generated by flow electrification and the injector wall. (2) The charged liquid is accelerated by applying a voltage to the electrodes, and tiny droplets are generated with a small pressure. moreover, (3) A fuel injection device and combustion chamber that take into account the effect of flow electrification achieve large output, torque, and high thermal efficiency for the power engine. The inventors have discovered that flow electrification causes various problems in the fuel supply and combustion of internal combustion engines. Here, we will explain the factors that determine the thermal efficiency of a heat engine and clarify the issues that need to be resolved. To realize an ideal engine with high thermal efficiency, it is necessary to use a fuel carburetor or an indirect or direct injection fuel injection device. 1. All injected fuel is injected into the cylinder. hand 2. Creates an optimal air-fuel mixture , in the mixture 3. Burn fuel molecules completely and at the optimal time Here, combustion at the optimum timing means combustion within a limited range centered around a crank angle of 90 degrees. This becomes clear if we consider that the force applied at the top and bottom dead center of the piston does not perform work. 1. All injected fuel is injected into the cylinder In a fuel carburetor or indirect injection system, all fuel droplets must be injected into the cylinder during the intake stroke, i.e., while the intake valve is open. In a carburetor, the ejection of fuel droplets is controlled by the gas flow velocity (wind speed) in the intake pipe, while in an indirect injection system, it is controlled by the fuel pump. However, if Coulomb attraction occurs between the fuel liquid, which is oppositely charged due to flow electrification, and the nozzle of these systems, some of the fuel droplets adhere to the nozzle, causing a delay in ejection (see Figure 32), and they may be left behind in the intake pipe instead of being taken into the cylinder (see Figures 39 and 40). Figure 39 shows the ejected droplets in an insulated state, and shows the pulse oscillation start time (the first pulse oscillation is set to 0) (X-axis), the ejection order (Y-axis), and the amplitude of oscillation V (Z-axis) of the 28 fuel injections in Figure 33. Figure 40 shows droplets that reach an insulated cylinder, and shows the pulse oscillation start time (the first pulse oscillation is set to 0) (X-axis) of the 28 fuel injections in Figure 36, the order of arrival (Y-axis), and the amplitude V of the oscillation (Z-axis). Most of the fuel left behind in the intake pipe passes through the cylinder and is discharged into the exhaust pipe while the intake and exhaust valves are simultaneously open at the end of the exhaust stroke and the beginning of the intake stroke (each at about 30 degrees crank angle), where it is thought to be burned during the compression stroke (see the compression stroke in Figure 43, the combustion stroke in Figure 44, the compression stroke in Figure 19, and the combustion stroke in Figure 20). This problem does not occur with direct injection.

[0011] 2. Creating an optimal air-fuel mixture The theoretical air-fuel ratio is estimated stoichiometrically. However, because stoichiometry does not include time as a factor, practical air-fuel ratios are determined empirically, taking into account power output and fuel economy, and can take a fairly wide range of values, including the theoretical air-fuel ratio. Depending on the engine speed, the fuel injector may not function properly (as indicated by the arrow in Figure 33), and the proportion of fuel taken into the cylinder and the proportion of fuel burned within the cylinder may vary. A stable fuel supply and the creation of an optimal fuel mixture are important for engine reliability and optimal operation. 3. Burn fuel molecules completely and at the optimal time As mentioned above, achieving high thermal efficiency requires complete combustion of fuel within a limited range centered around a crank angle of 90 degrees. The experimental results described in the appendix indicate that the earlier the fuel droplets are injected into the cylinder and the longer they remain there, and the more efficiently they receive heat from their surroundings, the higher the combustion rate during the combustion stroke. It appears that vaporization of fuel droplets requires a longer time than previously thought. The experimental results also indicate that combustion occurs during the compression and exhaust strokes (see the compression stroke in Figure 19, the exhaust stroke in Figure 20, the compression stroke in Figure 46, and the exhaust stroke in Figure 47). Combustion during the exhaust stroke acts as a brake on the piston's upward movement, which reduces the thermal efficiency of an internal combustion engine. The present invention solves these problems by miniaturizing fuel droplets and facilitating vaporization of fuel droplets injected into a cylinder. [Means for solving the problem]

[0012] One aspect of the fuel droplet injection device of the present invention is Flow electrification occurs and the charged A microdroplet injection device for an internal combustion engine equipped with an injection port for injecting droplets of liquid fuel, the device having an electrode disposed in front of the injection port, and the droplets injected from the injection port being accelerated by an electric field formed by applying a voltage to the electrode. and It is characterized by: Furthermore, one aspect of the fuel droplet injection device of the present invention is Flow electrification occurs and the chargedA micro-droplet injection device for an internal combustion engine equipped with an injection port for injecting droplets of liquid fuel, in which one or more electrodes are installed inside, and electrons in the pressurized liquid are vibrated by changing the potential of the electrodes, and the injection timing is adjusted by the potential to control the injection amount. and It is characterized by: [Effects of the Invention]

[0013] In the present invention, the liquid is accelerated and split in an electric field generated by an electrode placed in front of the microdroplet jetting nozzle, thereby efficiently jetting the microdroplets (claim 1). Furthermore, a voltage is applied to the microdroplet jetting nozzle or the electrode at the nozzle tip, causing the charged liquid to vibrate due to Coulomb force, thereby efficiently jetting out the microdroplets (claim 2). These methods make it possible to eject tiny droplets of less than 50 μm in diameter at lower pressure than ever before. Furthermore, by applying a voltage to the combustion chamber (cylinder, housing, etc.) of an internal combustion engine, the probability of collision between the charged fuel droplets and the combustion chamber wall is increased by Coulomb attraction, promoting heat exchange and increasing the rate at which the fuel droplets vaporize. Furthermore, by reducing the diameter of the fuel droplets to around 50 μm, the time required for vaporization can be shortened. These measures increase the combustion rate, enabling the creation of engines with greater power and torque. The increased combustion rate also reduces hydrocarbon components in exhaust gases, contributing to the prevention of air pollution and greenhouse gas emissions. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a conceptual diagram illustrating an automobile and an injection port of a fuel injection device, for explaining a first embodiment. [Figure 2] 1 is a conceptual diagram illustrating a cylinder and an injection port of an internal combustion engine, for explaining a first embodiment. [Figure 3] 1 is a conceptual diagram illustrating an automobile, an internal combustion engine, and an injection port for explaining a first embodiment. [Figure 4] FIG. 10 is a conceptual diagram illustrating an electrode facing an injection port, for explaining a second embodiment. [Figure 5]FIG. 10 is a conceptual diagram illustrating a jet nozzle connected to a high-pressure pump, explaining a third embodiment. [Figure 6] 10A to 10C are conceptual diagrams illustrating the operation of the injection port, explaining the third embodiment. [Figure 7] FIG. 10 is a conceptual diagram of an internal combustion engine (cylinder and cylinder head) to which a storage battery is connected, illustrating a fourth embodiment. [Figure 8] FIG. 10 is a conceptual diagram illustrating a conductor ring provided on a cylinder (cylinder head) for explaining the fourth embodiment. [Figure 9] FIG. 10 is a conceptual diagram showing a MEMS fuel injection device for explaining a fifth embodiment. [Figure 10] FIG. 10 is a conceptual diagram showing an intake pipe of a MEMS fuel injection device for explaining a fifth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a MEMS fuel injection device for explaining a fifth embodiment. [Figure 12] 10A and 10B are a side view and a front view of an ejection cell for explaining Example 5. [Figure 13] 1 is a conceptual diagram showing the influence of fuel pump pressure and Coulomb attractive force on the fuel liquid at the injection nozzle. [Figure 14] A conceptual diagram illustrating the collision of droplets inside a cylinder. [Figure 15] FIG. 4 is a characteristic diagram illustrating a change in potential in a conductive state, explaining the first embodiment. [Figure 16] A close-up of the first impulse in Figure 15. [Figure 17] A further enlargement of Figure 16. [Figure 18] FIG. 10 is a characteristic diagram showing engine sound measurement in a conductive state. [Figure 19] FIG. 19 is a characteristic diagram showing the power spectrum in FIG. 18. [Figure 20] FIG. 19 is a characteristic diagram showing the power spectrum in FIG. 18. [Figure 21] FIG. 10 is a characteristic diagram showing engine sound measurement in a conductive state. [Figure 22] FIG. 22 is a characteristic diagram showing the power spectrum in FIG. 21. [Figure 23] FIG. 22 is a characteristic diagram showing the power spectrum in FIG. 21. [Figure 24] FIG. 10 is a characteristic diagram showing the ejection time and arrival time of a droplet. [Figure 25] FIG. 10 is a characteristic diagram showing the ejection time and arrival time of a droplet. [Figure 26] FIG. 10 is a characteristic diagram showing the ejection time and arrival time of a droplet. [Figure 27] FIG. 10 is a characteristic diagram showing the ejection time and arrival time of a droplet. [Figure 28] FIG. 10 is a characteristic diagram showing the ejection time and arrival time of a droplet. [Figure 29] FIG. 10 is a characteristic diagram illustrating Example 4 when the start time of the air intake stroke is set to 0. [Figure 30] FIG. 4 is a characteristic diagram showing the results of a power measurement test. [Figure 31] FIG. 6 is a conceptual diagram illustrating in detail FIG. 5. [Figure 32] FIG. 10 is a conceptual diagram illustrating the state of fuel liquid adhering to the nozzle in the prior art (insulated state). [Figure 33] FIG. 4 is a characteristic diagram showing the potential measurement of the fuel injection device in an insulated state. [Figure 34] Enlarged view of the first impulse in Figure 33. [Figure 35] A further enlargement of Figure 34. [Figure 36] FIG. 10 is a characteristic diagram showing the potential measurement of the engine in an insulated state. [Figure 37] Enlarged view of the first impulse in Figure 36. [Figure 38] A further enlargement of Figure 37. [Figure 39] FIG. 10 is a characteristic diagram showing the characteristics of ejected droplets in an insulating state. [Figure 40] FIG. 10 is a characteristic diagram showing the characteristics of droplets that reach the cylinder in an insulating state. [Figure 41] FIG. 10 is a characteristic diagram showing the characteristics of droplets ejected in the present invention (conducting state). [Figure 42] FIG. 10 is a characteristic diagram showing engine sound measurement in an insulated state. [Figure 43] FIG. 43 is a characteristic diagram showing the power spectrum in FIG. 42. [Figure 44] FIG. 43 is a characteristic diagram showing the power spectrum in FIG. 42. [Figure 45] FIG. 10 is a characteristic diagram showing engine sound measurement in an insulated state. [Figure 46] FIG. 46 is a characteristic diagram showing the power spectrum in FIG. 45. [Figure 47] FIG. 46 is a characteristic diagram showing the power spectrum in FIG. 45. [Figure 48] 1 is a diagram showing the mathematical formulas used in the specification. [Figure 49] 1 is a diagram showing the mathematical formulas used in the specification. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, the embodiments of the present invention will be described with reference to examples. [Example]

[0016] In this embodiment, a fuel carburetor or an indirect injection type and a direct injection type fuel injection device mounted on an automobile will be described with reference to FIGS. 1 to 3 and 15 to 17. FIG. This fuel injection device increases the electrostatic capacitance of the injection nozzle to reduce the potential rise due to flow electrification. Also, this fuel injection device electrically connects the injection nozzle to the object to be injected, thereby suppressing the potential rise at the nozzle and the potential drop at the object to be injected. When generating minute droplets by ejecting pressurized liquid from a minute nozzle, the charged liquid experiences a drag force in the opposite direction to the flow due to flow electrification. For this reason, it is necessary to apply a large amount of pressure to eject minute droplets. In addition, the droplets adhere to the nozzle due to Coulomb attraction, and the droplets This causes a delay in the release of droplets. To reduce this effect, the capacitance of the ejector or nozzle is increased to suppress the rise in potential. If we consider the amount of charge Q generated by flow electrification per droplet ejection to be constant, then the product of capacitance C and potential V is a constant (equation (1) in Figure 48). To increase the capacitance, if the injector or nozzle is connected to a conductor with a large surface area (capacitance C0), the combined capacitance will be C' (=C0 +C>C). The relationship of the above formula (1) holds true with respect to the potential V' when connected (formulas (2) and (3) in FIG. 48). Therefore, by connecting the injection device or the injection nozzle to a conductor with a large capacitance, the rise in potential can be suppressed. To increase the capacitance C0 of the micro-droplet spray device or nozzle, it is necessary to connect it to a conductor with a large surface area (capacity C'). In this case, the combined capacitance C is C = C0 + C' > C'. For example, in an automobile, the body (frame, chassis) can be considered as a conductor with a large surface area (see Figure 1). It is also effective to make the paint on the surface of the car body an electrically conductive material to achieve conductivity, or to connect it to electrically conductive plastic parts. In order to suppress the rise in potential of the fuel carburetor or injector of an internal combustion engine and the drop in potential of the engine, the fuel injector and the engine are electrically connected (see Figures 2 and 3).The results of potential measurements clearly show that this almost completely eliminates the potential fluctuations that accompany fuel injection (see Figures 15 to 17). [Example]

[0017] In the second embodiment, a fuel injection device will be described with reference to FIG. This fuel injection device is characterized in that an electrode is provided in front of the injection nozzle, and when a voltage is applied to the electrode, charged liquid is accelerated in an electric field, causing droplets to be ejected from the injection nozzle. An electrode is placed in front of the nozzle of the microdroplet injection device in the injection direction, and a positive voltage is applied to the electrode to accelerate the negatively charged microdroplets in their direction of movement (see Figure 4 for use in an indirect fuel injection system for internal combustion engines). When the force due to the electric field and the pressure from the liquid feed pump exceed the Coulomb attractive force acting between the negatively charged liquid and the nozzle, the tip of the liquid breaks up and is ejected as droplets. The small pressure from the liquid feed pump disrupts the balance of the forces acting on the negatively charged liquid, allowing microdroplets to be ejected earlier than when there is no electric field. The positive charge generated on the tube wall by flow electrification moves toward the nozzle along with the negatively charged liquid, so the number density of positive charges is thought to be highest at the nozzle. Therefore, microdroplets with low initial velocity that exit the nozzle are thought to be attracted to the nozzle surface due to Coulomb attractive force. Acceleration by the electrode can reduce this adsorption. This method enables the miniaturization of the liquid feed pump and reduces manufacturing costs. It also reduces the vibration and noise generated by the high-pressure operation of the liquid feed pump and injection device. (Mitigation of noise and vibration in high-pressure fuel system of a gasoline direct injection engine, J. Borg, A. Watanabe and K. Tokuo, Procedia 48 (2012) 3170-3178). The timing of the release of the microdroplets can be adjusted by changing the magnitude and time of the voltage applied to the electrodes. This method can be used in a wide range of fields where microdroplet ejection is required, such as inkjet printing and devices that inject and burn liquid fuel and use the resulting energy as a power source (reciprocating engines, rotary engines, etc.).

[0018] By applying a positive voltage to an electrode placed in front of the nozzle of the microdroplet injection device, the negatively charged liquid is accelerated by an electric field, ejecting microdroplets. The electrode is preferably ring-shaped or cylindrical, with good symmetry so that the injected fuel droplets can pass through the hollow portion. The electrode is placed in an appropriate position close to the nozzle so as not to come into contact with the droplets and to avoid a large load voltage (see Figure 4). The voltage applied to the electrode depends on the amount of charge in the liquid, the mass of the droplets, and the distance between the nozzle and the electrode. In the experiment disclosed in paragraph 0031 and following, the increase in the potential of the injector was approximately 3 V when the injector and engine were insulated. Therefore, the load voltage is considered to be at most 10 V. When used in an internal combustion engine, a constant voltage can be applied constantly, but a pulse voltage can also be applied only for the duration of fuel droplet injection, synchronized with the operation of the fuel pump, corresponding to the crank angle, or by detecting the increase in potential at the nozzle. The charged liquid can be positively charged. [Example]

[0019] In the third embodiment, a fuel injection device will be described with reference to FIGS. 5, 6 and 31. FIG. This fuel injection device is characterized by having one or more electrodes installed inside, and by changing the potential of these electrodes, it vibrates electrons in the pressurized liquid, adjusting the injection timing with the potential and controlling the injection amount. The fuel injection device according to this embodiment differs from the injection device shown in Fig. 4 in that an electrode is installed at the injection port, and a storage battery, one end of which is grounded, is connected to the electrode. The diameter of the flow path of a microdroplet injection device is smallest at the injection port, and because the number of electrons absorbed into the liquid due to flow electrification increases as the flow distance increases, the electron density in the liquid is greatest at the injection port exit. Since the charged liquid moves, it carries with it the positive charge on the tube wall, and the surface density of positive charges on the tube wall is thought to be greatest near the injection port exit. For this reason, the Coulomb attractive force per unit volume acting on the charged liquid is greatest near the injection port exit. A force equilibrium state is momentarily reached between the Coulomb attractive force acting on the charged liquid and the pump pressure. At this time, if the potential of the injection port or the electrode installed at the injection port is lowered, the Coulomb attractive force decreases, disrupting the force equilibrium and causing the microdroplets to be ejected. If the potential is lowered further, the Coulomb repulsive force comes into play, and it is thought that microdroplets will be ejected even with low pump pressure (see Figure 5, which shows how it would look when used in a direct injection injection device for an internal combustion engine). In this way, by repeatedly raising and lowering the electrode voltage while pressurized by a high-pressure pump, and vibrating the liquid by alternating Coulomb attractive and repulsive forces, it can be used as a "unipolar electric vibration chopper" that separates the liquid and intermittently ejects it as droplets (Fig. 6, load voltage B). Furthermore, by slightly shifting the fluctuation period of each potential in a combination of multiple electrodes, increasing the amount of vibrating liquid and lengthening the amplitude of the vibration, it can be used as an "electric vibration chopper" with high injection efficiency that can also be used in injection devices with long flow passages. Figure 31 shows an example of use in a direct injection fuel injection device for an internal combustion engine.

[0020] An "electroosmotic chopper," which uses multiple electrodes to accelerate and vibrate charged particles in a solution, is a device with a similar structure to an electroosmotic pump. Here, we compare the fundamental principles and application modes of both devices to clarify the novelty and originality of this invention. Electroosmosis was discovered by F.F. Reuss (F.F. Reuss, Notice sur un nouvel effete l'électricité galvanique, Memoires de la Société Impériale des Naturalistes de Moscou, 1809, 2: 327-337). When a clay is sandwiched between two electrodes in water and a voltage is applied to the electrodes, a water current is generated. This phenomenon is currently explained as follows: When a solution comes into contact with a solid surface, ions in the solution adsorb to atoms on the surface of the substrate, forming a Stern layer. A Gouy-Chapman layer containing an excess of ions of the same type as the adsorbed ions forms outside of this. In the following, these ions are considered to be positive ions. The adsorbed ions in the Stern layer are fixed and cannot move, whereas the ions in the Gouy-Chapman layer move toward the electrode with the opposite polarity when an electric field is applied, dragging the solvent molecules along with them, resulting in a water flow (HJ. Butt, K. Graf and M. Kappl, “Physics and Chemistry of Interfaces, 3 rd (ed., 2013, Wiley-VCH, translated by Suzuki Yoshihito and Fukao Koji, Maruzen). Considering this, the steady-state flow velocity ν of the minute part flowing through the Gouy-Chapman layer is It is found by solving the Vier-Stokes equation (4) (equation (4) in Figure 48) and the continuity equation (equation (5) in Figure 48). Here, η represents the viscosity of the liquid, P represents the pressure applied to the liquid, ρ e is the charge density of the positive ions in the Gouy-Chapman layer, and E is the electric field applied by the electrode plate. To clarify that the first term is a drag force due to viscous forces, the pressure P and the electric field E are set to be parallel to the x-axis and in a positive direction, and their signs are reversed, so this is not the same as in the literature (HJ. Butt, K. Graf and M. Kappl). To calculate the flow velocity ν from equations (4) and (5), we utilize the fact that Poisson's equation (equation (6) in Figure 48) holds.

[0021] However, in addition to the ions of the same kind as the adsorbed ions, ions with opposite signs also exist in the liquid. Excluding the ions that cannot move by adsorption, the equation of motion considering all the ions that can move under the electric field must be considered. Therefore, for the tiny portion of the liquid sandwiched between the electrodes the Navier-Stokes equation (4) should be replaced as in equation (7) of Fig. 48. Here, ρ e is the charge density of the ions in the liquid, ρ e c represents the charge density of the counterions, and both are functions of position. Since the direction of the pressure P in equation (7) is made the same as the direction of the flow, it is opposite to equation (4). There is the following relationship between ρ e and ρ e c . Here, ρ e ad is the number density of the ions that will be included in the Stern layer among the ions in the liquid. Since ρ e ad is represented by equation (9) of Fig. 48, it can be expressed as in equation (10) of Fig. 48. Usually, the pressure P is 0, so the driving force of the electroosmotic flow as a macroscopic flow indicates that the force received by the same number of charges with opposite signs as the number of charges of the adsorbed ions in the electric field. Since the charge of the ions and the liquid molecules are bound and move by charge-dipole interaction, as a result, a macroscopic liquid flow occurs. However, for equation (8) to hold and for a steady flow to exist, if the number of ions adsorbed on the substrate is n ad and the number of adsorption sites on the substrate surface is N, the condition n << N must be satisfied. The velocity profile of the electroosmotic flow decreases near the interface in equation (4), and ρ eThe flow velocity should reach a minimum at the central axis of the channel where the velocity is smallest. In contrast, in equation (10), the flow velocity is maximum at the central axis, and when the diameter of the channel becomes sufficiently large, the ion concentration becomes constant except near the interface, so the flow velocity is also thought to be almost constant. The electroosmotic flow through a capillary tube observed under an optical microscope using fine particles as markers shows the profile predicted by equation (10) (HJ. Butt, K. Graf and M. Kappl, "Physics and Chemistry of Interfaces, 3 rd (ed., 2013, Wiley-VCH, translated by Suzuki Yoshihito and Fukao Koji, Maruzen). Equation (10) is a general equation for the steady-state flow rate when an electric field is applied to a liquid containing an electric charge, not just electroosmotic flow. For example, when an electric field is applied to an electrolyte solution in an electrolytic cell with a pressure of 0, the proportion of adsorbed ions becomes extremely small and ρ e ad is considered to be close to 0, so no macroscopic flow appears. Even when electrons are captured in the liquid by streaming electrification, ρ e ad If we consider is the number density of electrons in the liquid, it shows that the force acting on electrons in the electric field, together with pressure, creates a steady state of flow. However, the following differences can be seen between the case where electrons taken into the liquid by flow electrification are accelerated by an electric field and the case where electroosmotic flow accelerates ions contained in the solution.

[0022] (1) Pressure applied to a liquid Electrons are drawn into a liquid by flow electrification when a large pressure is applied to the liquid. However, in an electroosmotic pump, ions are already present in the solution, so there is no need to apply pressure to the solution. If any pressure is applied, it is only a small, supplementary pressure (Japanese Patent Laid-Open Publication No. 2004-276224). (2) Flow tube material In flow electrification, metal tubes are used to withstand large pressures, while in electroosmotic pumps, dielectrics (silica glass, oxide particle aggregates, polymers such as polycarbonate (PC) and polymethyl methacrylate (PMMA)) are used to adsorb specific ion species. (3) Type of liquidThere are no limitations on the type of liquid that can generate flow electrification. However, electroosmotic pumps require sufficient dissolved ions, so they are limited to polar solvents. Electroosmotic pumps, which use electroosmosis, are devices that transport minute amounts of solution by using an electric field to drive an ionic current through the solution. They are used in chemical analysis, chemical synthesis, and life sciences. An external electrode pair sandwiches a porous structure, such as a capillary tube, a channel formed on a substrate, or an aggregate of insulating particles, or an electrode pair installed inside the capillary tube. The electric field accelerates ions in the solution and transports the liquid. Since one electrode is positive and the other negative, the magnitude and direction of the ionic current are constant. In contrast, an "electrical chopper" is a device that varies the electrode potential to oscillate electrons, ejecting pressurized liquid from a nozzle as droplets. Liquid transport is mostly achieved by high-pressure pumps. In an "electrical oscillation chopper," two opposing electron flows are generated as the potential of the electrodes fluctuates. The electron flow reverses when the potential fluctuates again. This causes the liquid to vibrate parallel to the flow direction. If the vibration amplitude is large enough, the liquid is separated and ejected as droplets from the nozzle. A monopole electric oscillation chopper can inject droplets because it can vibrate electrons with just a single electrode. Using multiple electrodes allows for a larger volume of liquid to be vibrated, resulting in more efficient droplet injection. The use of a "monopole electric oscillation chopper" or "electrical oscillation chopper" in an internal combustion engine fuel injection system can reduce the size of fuel droplets, thereby improving fuel combustion efficiency. Adjusting the potential and the period of the potential fluctuation changes the volume of microdroplets and the number of injections, allowing for easy control of the injection volume per unit time. Direct injection systems have the advantage of being able to deliver all of the injected fuel into the cylinder. However, high pressure is required to inject the fuel. By using a "unipolar electric vibration chopper" or "electric vibration chopper," the pressure of the high-pressure pump can be reduced, which makes it possible to make the pump smaller and reduce costs. It is also possible to reduce the vibration and noise generated by high-pressure operation.(Mitigation of noise and vibration 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 where the injection of tiny droplets is required, such as inkjet printing and a wide range of devices powered by the energy generated by injecting and burning liquid fuel (such as rotary engines and jet engines).

[0023] An electrode is installed at the nozzle or part of the nozzle of the microdroplet ejection device (see Figure 5), and the liquid is sent to the nozzle with the potential raised. When sucking the liquid with the high-pressure pump, valve A is opened and valves B and C are closed. When sending the liquid toward the nozzle, valve A is closed and valves B and C are opened. Valve C can be closed when the liquid is ejected. Considering the effect of flow electrification, it is desirable that the diameter of the flow path upstream of valve C be sufficiently large. Although a syringe-type pump is shown in Figure 5, this does not exclude other types of pumps. Figure 31 shows an example of an electric vibration chopper used in a fuel droplet injection device for an internal combustion engine, with two electrodes. Electrodes 1 and 2 must be thick enough to withstand high pressures. By setting the flow path diameter of electrode 1 to, say, 100 μm and electrode 2 to 50 μm, the fuel can reach electrode 1 with less pressure than if both flow paths were 50 μm. In this case, electrode 2 can be made thicker to increase its mechanical strength. When used as a direct injection fuel injection device, it is desirable to minimize the space between electrode 1 and electrode 1 when valve C is closed. The electrode potentials are varied to intermittently eject fuel as droplets. Figure 31 also shows an example of the potential changes between electrodes 1 and 2 as valve C opens and closes. The time lags d1 and d2 between the on and off voltage loads on electrodes 1 and 2 should be adjusted to match the flow path length. When used in an injection system for a multi-cylinder engine, pressure can be constantly applied to the liquid in the reservoir, and multiple valves C can be installed in the reservoir, with only the valve C connected to the cylinder that requires fuel being opened. The negative terminal of the storage battery connected to the electrode is connected to the body. When combined with the fuel injection system of Example 2, the load voltage on the electrode can be reduced. A rough estimate is given below for an example of an internal combustion engine injection system using an "electrical vibration chopper" (Figure 31).

[0024] The engine is a 4-cycle, 500cc, single-cylinder gasoline engine with an engine speed of 6000 rpm. The fuel injection system is a direct injection system that can inject all fuel into the cylinder. The temperature of the air in the cylinder is 100°C. The molecular weight of gasoline is 80, and the density is 0.7 g / cm. 3 The air-fuel ratio is 13:1. At this time, the amount of gasoline required for two revolutions of the engine is approximately 0.05cc (5 x 10 10 μm 3) If we assume that the time required for gasoline vaporization can be ignored, the optimal time for gasoline injection is after the air intake has finished and the piston has passed bottom dead center. In this case, there is no increase in pressure inside the cylinder due to gasoline vaporization, so the maximum amount of air intake can be achieved. Gasoline is injected during the 2.5 ms of the compression stroke. To avoid knocking, it is desirable to inject as late as possible, but to vaporize the gasoline droplets, it is desirable to inject early. When gasoline is injected into the cylinder, the temperature of the mixture is lower when it is completely vaporized than when it is incomplete. This is because the latent heat of vaporization is greater. For this reason, knocking is thought to be less likely to occur if the gasoline droplets are miniaturized using an "electrical vibration chopper." We will consider the injection port, assuming that gasoline is injected 1 ms just before the end of the compression stroke (when the crank angle is 108 degrees from bottom dead center). If the diameter of the nozzle on the injection plate is 50 μm and droplets are ejected to a depth of 0.5 mm from the surface of the injection plate when the electrode voltage of the "electric vibration chopper" is lowered, the amount of droplets ejected from one nozzle in one injection is 9.8 × 10 5 The electrode voltage is changed at 100 kHz, and the gasoline is 5 × 10 10 μm 3 The number of nozzles required to spray this amount in 1 ms is approximately 530. If the nozzle spacing is 200 μm, then a nozzle plate with 530 nozzles and a diameter of 10 mm is sufficient. The sprayed droplets are slender, with 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, making them more likely to vaporize. Additionally, multiple agglomeration centers are formed, which is thought to cause them to break up immediately after spraying. [Example]

[0026] The effectiveness of increasing the combustion chamber potential can be seen by comparing the engine sound power intensity when the injector and engine are insulated and conductive. The engine potential drop is smaller when the injector and engine are insulated than when the injector and engine are insulated, resulting in a slight increase in the combustion chamber potential. The amount of gasoline in the cylinder is less when the insulated state than when the insulated state (see Figures 39 and 41). The engine sound power intensity during the combustion stroke is lower when the insulated state than when the insulated state (see Figure 20 Combustion Stroke and Figure 44 Combustion Stroke). If this result were solely due to the amount of gasoline, the amount of gasoline burned during the exhaust stroke (gasoline remaining unburned during the combustion stroke) would be greater in the conductive state because the fuel combustion rate during the combustion process is the same. Therefore, the engine sound power intensity would also be greater in the conductive state. However, as shown in Figure 20 (exhaust stroke) and Figure 44 (exhaust stroke), the power intensity in the insulated state is significantly greater than in the conductive state, which is the opposite of what we expected. If there is no difference in combustion during the exhaust stroke between the insulated and conductive states, it can be assumed that increasing the potential of the combustion chamber and increasing the collision probability of fuel droplets will increase the proportion of fuel burned during the combustion process. When comparing the power intensity during the combustion process of a motorcycle (KTM DUKE) in the insulated and conductive states, the conductive state is slightly greater, and there is a slightly higher frequency component. The results of the power output test showed that both the power and torque were approximately 50% greater in the conductive state than in the insulated state (see Figure 29). To increase the collision probability of electrically charged fuel droplets in the combustion chamber of an internal combustion engine and improve the efficiency of heat exchange, the potential of the cylinder, piston, or cylinder head is made higher than the ground potential. To raise the potential above ground, the cylinder, etc. is connected to the positive terminal of a storage battery, and the negative terminal of the storage battery is connected to the body (see Figures 7 and 8). If the capacitance of the cylinder, etc. is too large to apply a voltage, an electrode plate can be installed on the cylinder and piston or cylinder head, and a positive voltage can be applied to the electrode plate. Figure 8 shows an example of an annular conductive plate electrode installed on the cylinder or cylinder head. The start and end times of the voltage application can be synchronized with the operation of the fuel pump or controlled by the crank angle. [Example]

[0028] To reduce the size of fuel droplets ejected from fuel injectors in internal combustion engines to 10-50 μm in diameter, we utilize established technology known as MEMS (Micro Electro Mechanical Systems). MEMS is a device consisting of actuators, sensors, and controllers integrated on a substrate using microfabrication technology. The components of a fuel injector include an actuator that injects fuel, sensors that receive signals from detectors for engine speed, airflow, coolant temperature, throttle opening, and battery voltage, and a controller that controls the actuator and fuel ejection volume based on information from the sensors. Inkjet printer heads are already commercially available as MEMS for fluid ejection. Inkjet printer heads accelerate electrically conductive ink droplets using an electric field and control their position using electrode deflectors to precisely control the droplet flight position. Furthermore, ink droplets are reduced in diameter for finer printing, and the ejection frequency per unit time is increased for high-speed printing (see "Inkjet," edited by the Imaging Society of Japan, supervised by Masahiko Fujii, Tokyo Denki University Press). In fuel injection systems for internal combustion engines, the amount of fuel ejected per unit time is more important than droplet position control. To realize a fuel injection MEMS, it is necessary to solve the difficult problem of reducing the diameter of fuel droplets while simultaneously increasing the amount of fuel ejected per unit time. For this reason, this example proposes a MEMS-type fuel injection system that integrates the nozzles of the fuel injection system and simultaneously injects many tiny fuel droplets. The MEMS-type fuel injection system is equipped with a controller that instantly changes the amount of fuel supplied according to the engine speed. To increase or decrease the amount of fuel supplied, the number of operating injection cells or the injection time is adjusted based on information from sensors.

[0029] Here, the number of fuel nozzles n is estimated for the measured single-cylinder, 450cc, four-stroke engine operating at 6000 rpm and 20 liters / hour of fuel consumption. The fuel droplet injection conditions are a droplet diameter of 50 μm, an injection duration of 1 ms, and an injection frequency of 200 kHz. The estimated fuel consumption is considered an upper limit of consumption. A droplet injection frequency of 200 kHz has been achieved with inkjet printers. The number of fuel nozzles n is estimated as shown in equation (12) in Figure 49. The actuator of the injector is driven by vibrating a diaphragm using a piezoelectric element, ultrasonic vibrator, or electromagnet. Figures 9 to 12 show an integrated fuel injector with a piezoelectric actuator. A pulse voltage is applied to the piezoelectric element, causing it to deform and vibrate the diaphragm, which changes the volume of the pressure chamber, thereby ejecting fuel droplets from the nozzles of the injection cells (see Figures 10 and 11) that make up the fuel injector. By using multiple nozzles per injection cell, the number of actuators can be reduced (see Figure 12). The injection cell shown in the figure has 19 nozzles, resulting in approximately 530 injection cells. The volume of ejected fuel droplets is equal to the deformation of the pressure chamber volume, and the vibration frequency of the piezoelectric element is the frequency of the pulse voltage. For indirect injection, the integrated fuel injector is installed in the intake manifold as shown in Figures 10 and 11. When applied to a multi-cylinder engine, a single pressure pump and reservoir can supply fuel to all injection cells (see Figure 12). This is an integrated fuel injection device and can also be applied to some of the injection devices disclosed in Japanese Patent Application No. 2019-1495.

[0030] To investigate the effects of flow electrification due to droplet injection, we conducted potential measurements and engine sound measurements on the fuel carburetor or fuel injector of an internal combustion engine and the engine. The engines used for the measurements were motorcycles (HONDA MEN 450 and KTM 390 DUKE) with fuel supply via a fuel injection system and a motorcycle (HONDA KSE 125) with a fuel carburetor. The engines were electrically connected to the frame, but the injector and carburetor were insulated. Since these engines were all single-cylinder, it was easy to analyze potential changes and engine sound changes. The phenomena that occur in the four strokes of a single-cylinder engine, from intake to exhaust, remain unchanged even when the number of cylinders is increased. Measurements were performed using an oscilloscope (PicoScope 6 5444B, Pico Technology) and passive probes (TA045, Pico Technology) connected to the fuel carburetor or fuel injector and engine. A condenser microphone (EMM-6, Dayton Audio) was used to measure engine sound. The results and interpretation of the experiment will be explained in the order of potential difference measurement and engine sound measurement. While a method for determining engine speed from engine sound has been put into practical use, a method for evaluating the state of intake air, combustion, and exhaust from engine sound is not considered common, so the analysis method will also be explained.

[0031] A Potential measurement Figure 33 shows the results of potential measurements on a fuel injection system (HOND MEN 450) isolated from the engine. The engine speed is 6900 rpm. 50 Hz voltage fluctuations are added to the figure as noise. The impulse with an amplitude of ~60 V in the figure has a period of 17.5 ms, the same as the period of the air supply. Figure 34, which is an enlargement of the first impulse in the figure, shows that this impulse consists of multiple pulse vibrations, and that there is a slight rise in potential prior to the pulse vibrations. The slope of the potential rise decreases over time, showing a tendency to saturate. As is clear from Figure 35, which is a further enlargement of Figure 34, the magnitude of the potential rise is about 3 V. Figures 36 to 38 show the results of measuring the engine potential while it was isolated from the fuel injector. The engine speed was 7,300 rpm. In addition to 50 Hz noise, an impulse with an amplitude of approximately 3 V was observed, with a period of 16.3 ms, equal to the air intake period. Figure 37, an enlarged view of the first impulse in Figure 36, shows that this impulse consists of multiple pulse vibrations, and that the potential drops before the pulse vibrations. The absolute value of the slope of the potential drop decreases over time, showing a tendency toward saturation. As is clear from Figure 38, an enlargement of Figure 37, the magnitude of the potential drop is approximately 0.6 V.

[0032] The potential change was detected in both a motorcycle (KTM 390 DUKE) and a motorcycle (HONDA KSE 125) that uses a fuel carburetor. The magnitude of the potential change was more pronounced the larger the engine displacement and the higher the engine speed. Since the impulse period is equal to the air intake period, it is thought that when gasoline is pumped out by the fuel pump, flow electrification occurs, causing the fuel injection device to become positively charged. Flow electrification is the electrification of a moving liquid. This is a phenomenon in which a body becomes electrically charged, and gasoline becomes negatively charged due to flow electrification (see Non-Patent Document 2). The presence of multiple potential rises and pulse oscillations in one impulse indicates that gasoline droplets are intermittently released during a single air supply. The gasoline pushed out to the nozzle by the pressure of the supply pump is negatively charged, while the nozzle of the injector is positively charged, resulting in a Coulomb attractive force between the gasoline and the nozzle. It is believed that a state of force equilibrium is achieved between this attractive force and the pump pressure. However, if this equilibrium is broken by fluctuations such as air flow in the intake pipe, the fuel is released as droplets (see Figure 13). This repetition is thought to result in intermittent release of fuel droplets. The large amplitude (approximately 60 V) pulse oscillations that occur following the potential rise are thought to be caused by the sudden change in potential.

[0033] It is thought that the drop in the engine's potential is due to the receipt of electrons from fuel droplets that collide with the inner wall of the cylinder and the top surface of the piston. When fuel droplets or groups of fuel droplets that break down along the way arrive inside the cylinder in the order in which they are released and collide intermittently with the cylinder surface, the potential should change intermittently. When the droplets and droplet groups stop colliding with the cylinder surface and the supply of electrons stops, the potential changes suddenly. It is thought that this is why pulse vibrations with an amplitude of about 4V occur. The potential was measured by connecting a fuel injector (HOND MEN 450) and the engine with a 2 mm diameter copper wire. The results are shown in Figure 15. The engine speed was 8000 rpm. The pulse oscillation, with an amplitude of nearly 40 V, had a period of 15.0 ms, which was equal to the air intake period. Figure 16, an enlarged view of the first impulse in Figure 15, shows that the impulse is made up of multiple pulse oscillations. There is a slight drop in potential prior to the pulse oscillation. As shown in Figure 17, which is a further enlargement of Figure 16, the potential drop is small, at less than 0.3 V. We have considered the droplet release and arrival during the 28 intake strokes discussed in Figures 15 to 17 and Figures 33 to 38, and their characteristics will be explained using Figures 39 to 41. Figure 39 shows quantities related to the pulse oscillation obtained by measuring the potential of the insulated injector shown in Figures 33 to 35. The X axis represents the start time of subsequent pulse oscillations, with the start time of the first pulse oscillation of one impulse set to 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. Because the start time of the first pulse oscillation is likely to be different for each impulse, this discussion is not very strict. The amplitude of the first peak of the pulse oscillation is used as a measure of the amount of charge. Since the start time of the pulse oscillation is considered to be the release time of the fuel droplets, Figure 39 shows the characteristics of fuel droplet release. Most fuel droplets are released within approximately 0.8 ms of the start of release. Therefore, the droplet release duration can be considered to be approximately 0.8 ms. However, there are also quite a few droplets that are ejected between 1 ms and 4 ms, when the amplitude of the first peak of the pulse vibration gradually decreases. Most droplets are ejected by approximately the 10th ejection, but the ejection distribution is wide, extending to nearly 40 ejections. The amplitude of the first peak of the pulse vibration has a wide distribution, from 1 V to nearly 60 V. Considering that droplet volume is proportional to the amount of charge, this indicates a wide distribution of droplet volume.

[0034] Figure 40 shows quantities related to pulse vibration obtained by measuring the potential of the insulated engine shown in Figures 33 to 35. The quantities represented by the X, Y, and Z axes are the same as those in Figure 39. The start time of the pulse vibration is considered to be the time when the fuel and fuel droplets reach the inner wall of the cylinder, so Figure 39 shows the characteristics of the arrival of fuel droplets. Most droplets arrive within 0.6 ms of the arrival time of the first droplet. Therefore, the arrival time width of the droplets is considered to be approximately 0.6 ms. Furthermore, almost all droplets reach their target by the 15th release. The amplitude of the first peak of the pulse vibration is distributed up to nearly 1.5 V for fuel droplets that arrive within 0.6 ms, but all fuel droplets that arrive later have an amplitude of 0.5 V or less. Comparing the results in Figure 39 with those in Figure 40, it is clear that droplets that are released later are not injected into the cylinder despite being released from the injector. This issue will be discussed later in Section B (paragraphs 0033 and 0034) in conjunction with the results of engine sound measurements. Figure 41 shows the quantities related to pulse oscillation obtained from the potential measurements in the conduction state of Figures 15 to 17. The quantities represented by the X-axis, Y-axis, and Z-axis are the same as those in Figure 39. There are two distributions of pulse oscillation amplitude: 15 to 25 V and 5 V or less. Most droplets are emitted within 0.5 ms. The reason why the amplitude of the pulses emitted later is small, at 5 V or less, is thought to be because the droplet volume is small. The fuel droplets densely distributed in the 15 to 25 V range exist in the range where the number of emissions is up to 15. Considering that the charge on the fuel droplets is determined by the pressure applied to the liquid in the fuel injector and the area of ​​the vessel wall of the flow path, the charge should be the same in the insulated and conductive states. However, the maximum pulse vibration value in the conductive state is about 40 V (Figure 15), which is smaller than the maximum value of 60 V in the insulated state (Figure 33). This is thought to be because the electrostatic capacitance of the nozzle (injector) increases when connected to the engine, reducing the increase in potential at the injector or nozzle, thereby reducing the Coulomb attractive force acting on the charged gasoline liquid. As a result, droplets are ejected when the applied pressure is low. Comparing the results in Figure 41 with those in Figure 39, the time to droplet release is shorter and the droplet volume distribution is narrower than in the insulated state. This result also suggests that the Coulomb attractive force acting on the droplets is weak in the conductive state, causing droplets to be ejected when the applied pressure is low.

[0035] B. Engine noise measurement An engine can be thought of as a device that converts part of the energy generated by fuel combustion into acoustic energy. If the engine speed is constant, energy is generated during the combustion process, and as the process progresses, the intake and exhaust valves open and close periodically, changing the structure of the vibrating tube and the flow of gas, causing the engine sound to change periodically. If the magnitude of acoustic energy is proportional to the energy generated by fuel combustion, it is possible to evaluate the state of intake air, combustion, and exhaust by measuring engine sound. Sound energy per unit volume per cycle (energy density) <e>is expressed as equation (13) in Figure 49, and is proportional to the square of the frequency f and the square of the amplitude A. Here, ρ is the density of the medium through which the sound propagates. Sound intensity I is the energy propagated through a unit area per unit time, so it becomes equation (14) in Figure 49. Here, ν is the speed of sound in the medium. What is detected by the microphone is the sound pressure P, which is output as a voltage signal. The relationship between sound pressure P and sound intensity I is expressed as equation (15) in Figure 49. When the waveform (voltage signal) x(t) obtained by measurement is Fourier transformed, the amplitude spectrum X(f) is obtained as the Fourier coefficient (equation (16) in Figure 49). The energy is obtained by squaring and integrating the waveform x(t), and from Percival's equation (equation (17) in Figure 49), the square of the amplitude spectrum is the energy. Since the waveform obtained by measurement is a discrete sequence of numbers, the waveform x of the sample at N points in the analysis section is n Perform a discrete Fourier transform on the discrete Fourier coefficients X k (Equation (18) in FIG. 49). Then, the power spectrum P(k), which is the energy per unit time, is found as shown in Equation (19) in FIG.

[0036] Engine sound and potential measurements were carried out simultaneously. The distance between the microphone and the engine was 30 cm, so there was a delay of approximately 1 ms between the engine sound measurement signal and the potential measurement signal. The engine speed calculated from the impulse period of the potential measurement was 5000 to 6000 rpm (24 to 20 ms for the four strokes of intake, compression, combustion, and exhaust). The engine sound was analyzed as follows. The time width of each stroke is assumed to be equal, and 16 small sections are obtained by dividing each of the four cycles of the four strokes into four. The order of division into four is a, b, c, d, and the subscript numbers 1 to 4 are assigned to each cycle up to four cycles. The intake stroke is a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20, a21, a22, a23, a24, a25, a26, a27, a28, a29, a29, a30, a31, a32, a33, a34, a35, a36, a37, a38, a39, a40, a41, a42, a43, a44 2、 a 3、 a4, compression stroke is b1, b 2、 b 3、 The same applies to the combustion stroke and exhaust stroke. In the fitting of the spectrum analysis, the four subsections of each stroke, suffixed 1 to 4, were treated as a continuous section, and fitting was performed simultaneously for the intake stroke, compression stroke, combustion stroke, and exhaust stroke. The reason for fitting to four cycles is to increase the length of the analysis section and increase the frequency resolution. Since the start time of the intake stroke is unknown, the following assumptions are made: (1) The intake stroke begins (the intake valve opens) before the gasoline droplets are released. (2) The intake stroke start time (the time when the intake valve opens) is the same in both the insulated and conductive states. Furthermore, the fitting start time was changed in increments of 0.05 ms, and the fitting start time that satisfied the following conditions was determined as the start time of the air intake stroke. (1) The intake and exhaust valves are closed and no new energy is generated, so the power of the compression stroke is minimized. (2) If there is a change in frequency content, it occurs at the transition of each step. The following figures show the measurement data and analysis results. The engine noise spectrum (Figure 42) for the insulation state between the fuel injector and engine of a motorcycle (HOND MEN 450) is shown, along with the frequency dependence of the engine noise power, shown in the order of intake stroke (Figure 43), compression stroke (Figure 43), combustion stroke (Figure 44), and exhaust stroke (Figure 44). Figure 42 shows four cycles and 16 sub-intervals, which are further divided into four, shaded. The results for the conductivity state between the fuel injector and engine are similarly shown in Figures 18 to 20. The results for the motorcycle (KTM 390 DUKE) are similarly shown in Figures 45 to 47 and Figures 21 to 23, respectively. The start times of the intake strokes are summarized in Figure 29.

[0037] Comparing these results, the following can be seen regarding the insulation and conduction states of the motorcycles (HOND MEN 450 and KTM 390 DUKE): (1) The start of the intake stroke (opening of the intake valve) has almost the same phase in the engine sound spectrum. (2) When the engine is the same, the difference in the frequency distribution of the intake stroke is small. This confirms that the assumptions made at the beginning are correct. The results of comparing the insulation and conductivity of a motorcycle (HOND MEN 450) are listed below. (a) The time difference between the start of the intake stroke determined from the engine sound and the time of the pulse vibration indicating the first droplet ejection determined from the potential measurement is 0.3 ms in the insulated state and -0.1 ms in the conductive state. Since the detection of the engine sound is delayed by about 1 ms from the electrical signal, the actual time difference is approximately 1.3 ms and 0.9 ms, respectively. (b) During the compression stroke, the power is greater in the insulating state than in the conducting state. (c) During the combustion process, the power is significantly greater in the conductive state than in the insulated state. (d) During the exhaust stroke, the power is significantly greater in the insulated state than in the conductive state. Considering the results of the potentiometric measurements, these results are interpreted as follows.

[0038] (1) The reason why the power of the compression stroke is greater in the insulated state than in the conductive state is thought to be that in the insulated state, more gasoline remains in the intake pipe than in the conductive state, and when the intake valve and exhaust valve open simultaneously, the gasoline passes through the cylinder and reaches the exhaust system, where it is burned during the compression stroke. (2) The power of the combustion stroke is greater and the power of the exhaust stroke is less in the conductive state than in the insulated state. This is thought to be because in the conductive state, a larger amount of gasoline is taken into the cylinder and the combustion rate is higher. (3) The reason why the power of the exhaust stroke is greater in the insulated state than in the conductive state is thought to be that in the insulated state, a larger amount of gasoline remains unburned in the combustion stroke than in the conductive state, and this remaining gasoline is burned in the cylinder and exhaust pipe during the exhaust stroke. From this, it can be said that the decisive factors for improving the thermal efficiency of an engine that uses indirect fuel injection to achieve high power and torque are to increase the proportion of fuel taken into the cylinder by reducing the delay in the release time of the fuel droplets, and to increase the proportion of fuel burned by promoting the vaporization of the fuel droplets in the cylinder. A power measurement test (Dynojet, 250ix) was conducted on a motorcycle (KTM 390 DUKE) to compare the power output and torque in the insulated and conductive states, and the results are shown in Figure 29. The engine speed was 6000 rpm in both the insulated and conductive states. In the conductive state, both the power output and torque increased by about 50% compared to the insulated state. When comparing the engine sound power during the combustion stroke in the insulated and conductive states, the conductive state appears to be slightly louder than the insulated state, with the exception of the 150 Hz component (intake stroke in Figures 22 and 46).

[0039] C Droplet release time, arrival time and crank angle To compare the start time of the intake stroke with the release and arrival times of droplets, graphs of potential measurements and graphs of engine sound waveforms are superimposed in Figures 24 through 26. The dashed lines in the figures indicate the start time of the intake stroke, determined from engine sound data using the procedure described in B (paragraphs 0032 and 0033). Figure 24, which shows the injector potential in an insulated state, shows a group of vertical lines from 29 ms to 29.5 ms. These are impulses indicating droplet release. Figure 25, which shows the engine potential changes, shows the multiple vertical lines indicating the end of droplet arrival. Figure 26, which shows the potential changes when the injector and engine are electrically connected, shows the start time of the intake stroke as a dashed line between the vertical lines. The three graphs feature both thick lines indicating potential impulses and thin lines indicating that these impulses are added to the engine sound waveform as noise. It can be seen that the time difference between droplet release and discharge is reduced by electrically connecting the injector and engine. The results are summarized in Figure 29. For reference, the results for the KTM 390 DUKE are also shown. Figure 29 also includes values ​​corrected for the delay in sound detection (up to 1 ms). The release and arrival times in the table are the release and arrival time widths of the droplets reaching the cylinder, calculated from the graphs in Figures 39 to 41. Since the engine speed differed for each measurement and simple comparisons based on time are not possible, Figures 27 and 28 show a comparison based on crank angle. Figure 27 is a graph that considers the time when the piston is at top dead center as the start of the intake stroke. If both the intake and exhaust valves are open within a 30-degree range around top dead center, the exhaust valve is closed when the release of fuel droplets begins, regardless of whether the engine is in an insulated or conductive state, and the released fuel droplets do not pass through the cylinder and are exhausted. The piston displacement speed (wind speed) reaches its maximum near the end of the release time. The reason why droplets released later than this cannot reach the cylinder is thought to be because the wind speed becomes smaller along the way. Figure 28 is a graph showing the start of the intake stroke as the time when the piston is at a position 30 degrees before top dead center. The release of fuel droplets in the insulating and conducting states begins before the exhaust valve closes. The end of the droplet release period in the conducting state is well before the time when the piston displacement speed (wind speed) reaches its maximum, so it is thought that most of the droplets reach the cylinder. It is noteworthy that in the two examples where the crank angle GTE at the moment the intake valve opens is different, the piston displacement ends before it has reached halfway at the final release time when the droplets can reach the cylinder. This is thought to be because the air volume expands due to the heat inside the cylinder and some of the gasoline vaporizes, canceling out the drop in pressure inside the cylinder caused by the piston's displacement toward the bottom dead center, and the air velocity in the intake pipe approaches zero.

[0040] D Summary We have already mentioned that the time required for fuel droplet vaporization is longer than previously thought. This is thought to be due to electrons being trapped in the fuel droplets due to flow electrification. The electrons dielectrically polarize the fuel molecules, increasing intermolecular forces and the droplet's cohesive force (JN Israel Achevili, Intermolecular Forces and Surface Forces, 2nd ed., 1996, Asakura Shoten). Therefore, a charged fuel droplet requires more heat to vaporize than an electrically neutral one. Furthermore, because a charged fuel droplet reduces the probability of collision with the cylinder wall, piston surface, and cylinder head inner surface, the amount of heat received from the collision is thought to be reduced. When a charged fuel droplet enters the cylinder and collides with the surrounding walls, the cylinder accepts electrons, resulting in a decrease in potential. Therefore, the charged fuel droplet is subjected to Coulomb repulsion from the cylinder wall and the top surface of the piston. Even if the magnitude of this repulsion is small, the fuel droplet cannot collide with the cylinder wall or the top surface of the piston if the incident angle is sufficiently large (see Figure 14). Therefore, the collision probability of fuel droplets is smaller than when Coulomb repulsion is not at work, and it takes longer to obtain the heat required for vaporization.The reason why the power of the engine sound increases when the injector and engine are electrically connected is thought to be because the amount of fuel injected into the cylinder increases, the time it takes for the fuel to receive heat within the cylinder is longer, and the decrease in the potential of the inner walls of the cylinder, etc. is suppressed, reducing the degree of decrease in the collision probability, and the amount of heat received through collisions is greater than when insulated. In a direct injection fuel injection system, all injected fuel is taken into the cylinder and is not lost to the outside. However, since the airflow inside the cylinder is slower than the airflow in the intake pipe of an indirect injection system, it is thought that the fuel droplets are less likely to break down and vaporize. Therefore, in a direct injection fuel injection system, there is a particularly strong demand for the fuel droplets to be made smaller at the time of injection. To make the fuel droplets smaller, a high pressure pump must be applied to the liquid fuel, and it must be injected from a small-diameter nozzle. As a result, the effect of flow electrification will be even more pronounced in direct injection systems than in indirect injection systems.

[0041] The embodiments of the present invention have been described above with reference to the examples. The present invention aims to provide an efficient micro-droplet ejection device that controls the effects of flow electrification, but the micro-droplet ejection device that controls the effects of flow electrification includes not only the inventions set forth in the claims, but also inventions with the configurations described in the above examples, for example. Examples of such devices include a microdroplet jetting device having an injection port, an electrode provided in front of the injection port, and applying a voltage to the electrode to accelerate negatively charged liquid in an electric field and eject microdroplets from the injection port; a microdroplet jetting device having an injection port, one or more electrodes installed inside, and changing the potential of the electrodes to vibrate electrons in the pressurized liquid and adjust the injection timing with the potential to control the injection amount; a microdroplet jetting device having an injection port, and applying a positive voltage to an object to be jetted, causing Coulomb attraction to act on the negatively charged microdroplets, thereby increasing the probability of collision with the object to be jetted, and an injection port; an actuator that accelerates the liquid by vibrating a vibration plate to facilitate vaporization of the liquid and improve the thermal efficiency of the object to be jetted; sensors that receive signals from detectors for air flow rate, engine speed, cooling water temperature, throttle opening, battery voltage, etc., and a controller that controls the liquid jet amount based on information from the sensors, and which jets microdroplets of particle size 50 μm or less from a plurality of injection ports; There are micro-droplet injectors that spray micro-droplets of fuel of 50 μm or less. All of these micro-droplet injectors can efficiently inject micro-droplets.< / e>

Claims

1. A micro-droplet injection device for an internal combustion engine having an injection port that generates flow electrification and injects droplets of charged liquid fuel, characterized in that the device has an electrode arranged in front of the injection port, and the droplets injected from the injection port are accelerated by an electric field formed by applying a voltage to the electrode.

2. A micro-droplet injection device for an internal combustion engine that is equipped with an injection port that generates flow electrification and injects droplets of charged liquid fuel, characterized in that one or more electrodes are installed inside and the electrons in the pressurized liquid are vibrated by changing the potential of the electrodes, and the injection timing is adjusted with the potential to control the injection amount.

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