JP2022079794A - Fuel droplet injection device - Google Patents

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

The present invention relates to a fuel droplet injection device that disperses fuel droplets in a combustion chamber to increase the thermal efficiency of an internal combustion engine and reduces emissions of unburned Hydro-Carbon (UHC).

As an injection device that injects a liquid into an injected object in the form of minute droplets, for example, there is a technique for improving the thermal efficiency of an internal combustion engine (engine) by optimizing the combustion of fuel. When the liquid passes through the injector or vaporizer, flow charging occurs, and the injector or vaporizer and the liquid are charged positively and negatively (may be negative and positive depending on the combination of substances), and the droplet and the jet are ejected. Coulomb attraction works between the device and the like. It is considered that the main reason why a large pressure is required for the ejection of the droplet as the diameter of the droplet becomes smaller is the Coulomb attraction due to this flow charge. In internal combustion engines, it is necessary to overcome the decrease in fuel combustion ratio due to the delay in emission of fuel droplets and the delay in vaporization caused by the Coulomb attraction, achieving high thermal efficiency, high output and torque, and improving the combustion ratio. By doing so, the content ratio of hydrocarbons in the exhaust gas is reduced.

Japanese Unexamined Patent Publication No. 200-110746 Japanese Unexamined Patent Publication No. 202-11253 Japanese Unexamined Patent Publication No. 2004-301099

Bardi, M., Pilla, G. and Gautot, X., International Journal of Engine Research, Vol.20, No.1 (2019), pp.128-140 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 Koci, C.P., Fitzgerald, R.P., Ikonomou, V., and Sun, K., International Journal of Engine Research, Vol. 20, No.1 (2018), pp.105-127. J.N. Israel Acehvili, Intermolecular Force and Surface Force 2nd Edition 1996 Asakura Shoten

In an internal combustion engine, the fuel droplets injected from the fuel injection device are dispersed in the combustion chamber, and the surface area of the fuel droplets or the contact surface area with the combustion chamber wall is widened to burn the liquid fuel for power and thrust. It improves the thermal efficiency of the engine and suppresses the emission of non-combustion hydrocarbons (UHC).
In a study of Unburned Hydro-Carbon in the exhaust gas of gasoline-powered vehicles, it was pointed out that the wetness of fuel around the fuel injection port, intake valve and exhaust valve, and piston surface is an important cause of UHC generation. (See Non-Patent Documents 1-3). Since the ultimate temperature in the combustion stroke of the internal combustion engine is as high as ~ 800 ° C, the temperature of the combustion chamber wall is sufficiently higher than the vaporization temperature of the fuel liquid even if it is cooled by the circulating cooling water, and it is burned by the direct injection fuel injector. Droplets of gasoline, light oil, etc. injected into the chamber appear to vaporize immediately.

However, when the combustion stroke time is as short as about 10 ms and the fuel is sprayed on a specific part of the combustion chamber wall at a high pressure of 100 MPa to 200 MPa, the temperature drops due to the small specific heat of the inner wall member. It is considered that the wall of the combustion chamber becomes wet when the heat conduction from the above-mentioned part is not in time. The inventors have discovered that the fuel liquid is charged (flow-charged) by friction with the liquid feed pipe or the injection pipe when 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 attraction acting between the charged and the dielectrically polarized molecules (see Non-Patent Document 4), and the charged fuel liquid. Then, the heat of vaporization may be large.
The present invention has been made under such circumstances, and effectively disperses fuel droplets in the combustion chamber to improve the thermal efficiency of the internal combustion engine and reduce the emission of unburned hydrocarbons (UHC). To provide a fuel droplet injection device.

One aspect of the fuel droplet injection device of the present invention includes an injection port and a pair or a plurality of electrodes installed in front of the injection port in the injection direction, and the potential of the electrodes is sequentially changed and charged by an electric field. By sequentially changing the traveling direction of the fuel droplets and widely dispersing the fuel droplets in the combustion chamber, the vaporization of the fuel droplets in the combustion chamber is promoted to increase the thermal efficiency of the combustion engine and non-combustion hydrocarbon. It is characterized by reducing the emission of hydrogen (UHC).
It has been clarified by the inventor from the experimental results described in Patent Document 2 that the course of the fuel droplet charged by the electrode can be changed.

Fuel droplets in the combustion chamber can be effectively dispersed to increase the thermal efficiency of the combustion engine and reduce the emission of non-combustible hydrocarbons (UHC).
Combustion is a chemical reaction that occurs in a mixed state of fuel gas and reaction gas (oxygen) near the interface between fuel and gas (oxygen). Therefore, when the liquid fuel is burned to obtain power and thrust, the combustion stroke time 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 conduction heat from the combustion chamber wall. When the injected fuel droplets are dispersed and adsorbed on the wall of the combustion chamber, the droplets are vaporized by the heat around the adsorbed portion, so that wetting does not occur. However, when a large number of droplets or most of the injected fuel are concentrated and adsorbed on the fuel chamber wall, the specific heat of the members of the combustion chamber wall is small and the temperature of the location drops, so that sufficient heat of vaporization occurs. Cannot be obtained. Therefore, it is considered that vaporization is delayed and the combustion chamber wall becomes wet. Considering the collision with gas molecules and the vaporization by radiant heat from the combustion chamber wall, it is clear that it is more efficient to disperse the fuel droplets to increase the surface area than to concentrate them.

It is a top view of the electrode and the injection port arranged in front of the injection port explaining Example 1. FIG. It is a side view of the electrode and the injection port arranged in front of the injection port explaining Example 1. FIG. It is a top view which shows the potential of the electrode arranged in front of the injection port which concerns on Example 1. FIG. It is a side view which shows the electric potential of the electrode arranged in front of the injection port which concerns on Example 1, and the emission direction of a droplet. It is a diagram of the potential of the electrode arranged in front of the injection port explaining Example 1. FIG. It is a figure which shows the injection port which concerns on Example 1. FIG.

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

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 to F) installed in front of the injection port 5 in the injection direction. The potentials of the electrodes 6 (A to F) are sequentially changed, and the traveling direction of the fuel droplets 10 charged by the electric field is sequentially changed to widely disperse the fuel droplets 10 in the combustion chamber. By widely dispersing the fuel droplets 10, conduction heat can be efficiently obtained from the wall surface of the combustion chamber, so that the vaporization of the fuel droplets 10 is promoted, the combustion ratio of the fuel is increased, and the thermal efficiency of the combustion engine is increased. And at the same time it is possible to reduce the emission of non-combustible hydrocarbons (UHC).

In this way, a plurality of electrodes are installed in front of the injection port of the liquid fuel injection port to generate an electric field, and the traveling direction of the fuel droplet negatively charged by the injection is changed. The traveling direction of the fuel droplets is changed over time, and the fuel droplets are evenly and widely dispersed in the combustion chamber. It is possible to change the traveling direction of the injected fuel with time in the uniaxial direction by changing the voltage even with one electrode. However, in order to disperse the fuel droplets evenly and widely in the combustion chamber, it is desirable that the number of electrodes is two or more.

Figures 1 to 4 show an example of widely dispersing the injected fuel droplets in the combustion chamber. FIG. 1 is a plan view of a device composed of six flat plate electrodes 6 (A to F) arranged in a circle, and FIG. 2 is a side view of the device. When the potential is set as shown in FIG. 3, the negatively charged fuel droplet receives an attractive force in the direction of the high potential electrode A and a repulsive force from the low potential electrode D as shown in FIG. 4, and progress thereof. The direction can be bent from D to A. Therefore, if the potential of the electrode is changed with time as shown in FIG. 5, the fuel droplets can be dispersed in the combustion chamber. In this embodiment, the number of electrodes is 6, but the traveling direction can be finely changed by increasing the number of electrodes. In this case, instead of changing the potentials of the electrodes in order, it is possible to select the electrode pair at the position farthest from the electrode pair to which the voltage is applied and change the potential, thereby changing the potential in the combustion chamber. Fuel droplets can be selectively sprayed on hot parts of the wall.
When the potential is set as shown in FIG. 3, the negatively charged fuel droplet moves in the D → A direction due to the electric field created by the high potential electrode A and the low potential electrode D as shown in FIG. Can be bent. Therefore, if the potential of the electrode is changed with time as shown in FIG. 5, the fuel droplets can be dispersed in the three axial directions in the combustion chamber. In this embodiment, there are three pairs of parallel electrodes, but by increasing the number of electrodes, the traveling direction of the fuel droplets can be changed more finely.

The change in the angle of the fuel droplet in the traveling direction can be adjusted by the voltage applied to the electrode and the width of the electrode (the length in the traveling direction of the fuel). The traveling direction of the fuel droplets not only changes radially with respect to the traveling direction, but also changes in the axial direction. This is because the pressure applied to the fuel with the injection decreases and the velocity of the fuel droplets decreases, so that the change in the angle of the fuel droplets in the traveling direction due to the electric field increases with time.

1 ... Cylinder head 2 ... Cylinder 3 ... Combustion chamber 4 ... Piston 5 ... Injection port 6 ... Electrodes (A to F)
7 ・ ・ ・ Insulation material 10 ・ ・ ・ Fuel droplets

Claims (1)

The fuel liquid is provided with an injection port and a pair or a plurality of electrodes installed in front of the injection port in the injection direction, the potential of the electrodes is sequentially changed, and the traveling direction of the fuel droplet charged by the electric field is sequentially changed. By widely dispersing the droplets in the combustion chamber of the combustion engine, the fuel droplets in the combustion chamber are effectively dispersed to increase the thermal efficiency of the combustion engine and reduce the emission of non-combustible hydrocarbons. Fuel droplet injection device.

Images