Fuel droplet injection device

Abstract

To provide a fuel droplet injection device for effectively dispersing fuel droplets in a combustion chamber to enhance the thermal efficiency of a combustion engine while reducing the exhaustion of noncombustible hydrogen carbide.SOLUTION: The fuel droplet injection device includes an injection port 5, and a pair of or a plurality of electrodes 6 (A-F) installed in front of the injection port in an injection direction, and is configured to sequentially change potentials of the electrodes, sequentially change a moving direction of furl droplets 10 charged by an electrical field, and disperse the fuel droplets widely in a combustion chamber of an internal combustion engine so that the effective disperse of the fuel droplets in the combustion chamber enhances the thermal efficiency of the internal combustion engine while reducing the exhaustion of noncombustible hydrogen carbide.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a fuel droplet injector that disperses fuel droplets in a combustion chamber to increase the thermal efficiency of an internal combustion engine while reducing unburned hydro-carbon (UHC) emissions. [Background technology]

[0002] As an injection device that injects liquid in the form of minute droplets onto a target, for example, there is a technology that aims to improve the thermal efficiency of an internal combustion engine by optimizing fuel combustion. When a liquid passes through an injection device or a carburetor, flow electrification occurs, and the injection device or carburetor and the liquid are respectively charged positively and negatively (or negatively and positively depending on the combination of materials), and Coulomb attraction acts between the droplets and the injection device, etc. The smaller the droplet diameter, the greater the pressure required to eject the droplets. This Coulomb attraction due to flow electrification is thought to be the main reason. In an internal combustion engine, it is necessary to overcome the delay in the release of fuel droplets caused by Coulomb attraction and the decrease in the fuel combustion rate due to the delay in vaporization, and to achieve high thermal efficiency, high power and torque, while improving the combustion rate to reduce the hydrocarbon content in the exhaust gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-110746 A [Patent Document 2] JP 2020-112153 A [Patent Document 3] JP 2004-301099 A [Non-patent literature]

[0004] [Non-Patent Document 1] Bardi, M., Pilla, G. and Gautot, X., International Journal of Engine Research, Vol.20, No.1 (2019), pp.128-140 [Non-Patent Document 2] Schuck, C., Samenfink, W., Schunemann, E., Tafel, S., Towae, O., and Koch, T., International Journal of Engine Research, Vol.19, No.1 (2019), pp.78-85 [Non-Patent Document 3] Koci, CP, Fitzgerald, RP, Ikonomou, V., and Sun, K., International Journal of Engine Research, Vol. 20, No. 1 (2018), pp. 105-127. [Non-Patent Document 4] JN Israel Achevili, Intermolecular and Surface Forces, 2nd Edition, 1996, Asakura Publishing Summary of the Invention [Problem to be solved by the invention]

[0005] In an internal combustion engine, fuel droplets injected from a fuel injector are dispersed within the combustion chamber, increasing the surface area of ​​the fuel droplets or the contact surface area with the interior wall of the combustion chamber, thereby improving the thermal efficiency of the engine, which burns liquid fuel to generate power and thrust, and suppressing the emission of unburned hydrocarbons (UHC). In a study of unburned hydrocarbons in the exhaust gas of gasoline-powered vehicles, it has been pointed out that fuel wetting around the fuel injection port, on the intake and exhaust valves, and on the piston surface is an important cause of UHC generation (see non-patent literature 1-3). The temperature reached during the combustion process of an internal combustion engine is so high at up to 800°C that even if it is cooled by circulating cooling water, the temperature of the combustion chamber inner wall becomes sufficiently higher than the vaporization temperature of the fuel liquid, and it seems that the droplets of gasoline, diesel, etc. injected into the combustion chamber by a direct fuel injector vaporize immediately.

[0006] However, when the combustion stroke time is short, about 10 ms, and the fuel is sprayed at a specific location on the inner wall of the combustion chamber at a high pressure of 100 MPa to 200 MPa, it is considered that the temperature drops due to the small specific heat of the inner wall material, and when the heat conduction from other locations cannot keep up, the inner wall of the combustion chamber becomes wet. The inventors discovered that the fuel liquid becomes charged (flow electrified) due to friction with the liquid feed pipe and the injection pipe when it is injected from the injection device (see Patent Document 1). It is considered that the cohesive force of the charged fuel liquid is larger than that of the uncharged state due to the Coulomb attractive force acting between the charge and the dielectrically polarized molecules (see Non-Patent Document 4), and the heat of vaporization of the charged fuel liquid may be larger. The present invention has been made in view of the above circumstances, and provides a fuel droplet injection device that effectively disperses fuel droplets in the combustion chamber to increase the thermal efficiency of an internal combustion engine while reducing the emission of unburned hydro-carbons (UHC). [Means for solving the problem]

[0007] One aspect of the fuel droplet injection device of the present invention comprises: A fuel droplet injection device that injects flow-charged fuel droplets, in which the injected fuel droplets are electrically charged, without the need for a device such as a charging electrode that charges the fuel droplets. A jet nozzle and a pair of nozzles installed in front of the jet nozzle in the jet direction. Multiple Pairs and an electrode of The voltage of a pair of electrodes is changed, or the potential of the plurality of pairs of electrodes arranged opposite each other is sequentially changed in a certain direction. A fuel droplet injection device characterized in that the fuel droplets are widely dispersed within a combustion chamber of an internal combustion engine, thereby effectively dispersing the fuel droplets in the combustion chamber, thereby increasing the thermal efficiency of the combustion engine and reducing the emission of unburned hydrocarbons. Effect of the Invention

[0008] It is possible to effectively disperse fuel droplets in the combustion chamber to increase the thermal efficiency of a combustion engine while reducing the emission of unburned hydrocarbons (UHC). Combustion is a chemical reaction that occurs in the mixed state of fuel gas and reactant gas (oxygen) near the interface between the fuel and gas (oxygen). Therefore, when burning liquid fuel to obtain power and thrust, the combustion process is short, so it is particularly necessary to efficiently vaporize the fuel droplets. Most of the heat required for vaporization of the fuel liquid is considered to be conductive heat from the combustion chamber wall. If the injected fuel droplets are dispersed and adsorbed to the combustion chamber wall, the droplets will vaporize due to the heat around the adsorbed area, so wetting will not occur. However, if a large number of droplets or most of the injected fuel are concentrated and adsorbed on the combustion chamber wall, the specific heat of the material of the combustion chamber wall is small, so the temperature of the area drops, and sufficient heat of vaporization cannot be obtained. For this reason, vaporization is delayed, and wetting is considered to occur on the combustion chamber wall. Even when considering collisions with gas molecules and vaporization due to radiant heat from the combustion chamber wall, it is clear that it is more efficient to disperse the fuel droplets to increase their surface area than to concentrate them. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view of an electrode disposed in front of an injection nozzle and the injection nozzle for explaining the first embodiment. [Diagram 2] FIG. 2 is a side view of the electrode disposed in front of the nozzle and the nozzle for explaining the first embodiment. [Diagram 3] 4 is a plan view showing the potential of an electrode disposed in front of the jet nozzle according to the first embodiment. FIG. [Figure 4] 4 is a side view showing the potential of an electrode disposed in front of the nozzle and the ejection direction of droplets according to the first embodiment. FIG. [Diagram 5] 4 is a diagram of the potential of an electrode disposed in front of the injection port to explain Example 1. [Figure 6] FIG. 2 is a diagram showing an injection port according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiment of the present invention will be described with reference to the examples. EXAMPLES

[0011] The fuel droplet injection device of this embodiment includes an injection port 5 for injecting fuel droplets, and a pair or a plurality of electrodes 6 (A-F) disposed in front of the injection port 5 in the injection direction. The potential of the electrodes 6 (A-F) is sequentially changed, and the traveling direction of the fuel droplets 10 charged by the electric field is sequentially changed, so that the fuel droplets 10 are widely dispersed within the combustion chamber. By widely dispersing the fuel droplets 10, it is possible to efficiently obtain conductive heat from the wall surface of the combustion chamber, which promotes the vaporization of the fuel droplets 10, increases the fuel combustion rate, and increases the thermal efficiency of the combustion engine, while at the same time reducing the emission of unburned hydrocarbons (UHC).

[0012] In this way, multiple electrodes are installed in front of the liquid fuel nozzle to generate an electric field, which changes the direction of travel of the negatively charged fuel droplets caused by injection. The direction of travel of the fuel droplets is changed over time, dispersing the fuel droplets widely and evenly within the combustion chamber. It is possible to change the direction of travel of the injected fuel in one axial direction over time by changing the voltage with even a single electrode. However, to disperse the fuel droplets widely and evenly within the combustion chamber, it is desirable to use two or more pairs of electrodes.

[0013] An example of widely dispersing injected fuel droplets in a combustion chamber is shown in Figs. 1 to 4. Fig. 1 is a plan view of an apparatus consisting of six flat plate electrodes 6 (A to F) arranged in a circle, and Fig. 2 is a side view of the same. When the potential is set as shown in Fig. 3, the negatively charged fuel droplets are attracted to the high potential electrode A as shown in Fig. 4, and are repulsed by the low potential electrode D, so that their travel direction is bent from D to A. Therefore, by changing the electrode potential over time as shown in Fig. 5, it is possible to disperse the fuel droplets in the combustion chamber. In this embodiment, the number of electrodes is six, but the travel direction can be changed finely by increasing the number of electrodes. In this case, instead of changing the electrode potential in sequence, it is also possible to change the potential by selecting the electrode pair located farthest from the electrode pair to which the voltage is applied, and by doing so, the fuel droplets can be selectively sprayed onto the high temperature part of the inner wall of the combustion chamber. When the potential is set as shown in Figure 3, the negatively charged fuel droplets are deflected in the direction from D to A by the electric field created by the high potential electrode A and the low potential electrode D as shown in Figure 4. Therefore, by changing the electrode potential over time as shown in Figure 5, it is possible to disperse the fuel droplets in three axial directions in the combustion chamber. In this embodiment, three pairs of parallel electrodes are used, but by increasing the number of electrodes, the direction of the fuel droplets can be changed more finely.

[0014] The change in angle of the fuel droplet's traveling direction can be adjusted by the voltage applied to the electrode and the width of the electrode (the length of the fuel traveling direction). The traveling direction of the fuel droplet not only changes radially around the traveling direction as an axis, but also in the axial direction. This is because the pressure applied to the fuel decreases with injection, slowing down the speed of the fuel droplets, and the change in angle of the traveling direction of the fuel droplets caused by the electric field increases over time. [Explanation of symbols]

[0015] 1. Cylinder head 2. Cylinder 3. Combustion chamber 4. Piston 5...Injection port 6...Electrode (A~F) 7. Insulation material 10...fuel droplets

Claims

[Claim 1] A fuel droplet injection device in which fuel droplets are flow-charged, the device comprising an injection nozzle and one or more pairs of electrodes arranged forward in the injection direction of the injection nozzle, and by changing the voltage of the pair of electrodes or sequentially changing the potential of the multiple pairs of oppositely arranged electrodes in a fixed direction, the fuel droplets are widely dispersed within a combustion chamber of an internal combustion engine, thereby effectively dispersing the fuel droplets in the combustion chamber, thereby increasing the thermal efficiency of the combustion engine and reducing emissions of non-burned hydrocarbons.

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