RU2634972C1 - Laser spark plug - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: laser spark plug comprises a housing, an insulator, a microchip laser mounted in a cavity inside the insulator, an optical window, a focusing lens and a target installed in the prechamber with multiple output holes entering it at an angle, wherein the target is set at the central fairing installed coaxially with the axis of the laser spark plug, and on the side wall of the central fairing swirl vanes are mounted. A laser spark plug may comprise an additional optical window with a protective cavity between the optical window and an additional optical window. The microchip laser is mounted on the shock absorber. On the insulator, on the side of the inner cavity, a metallized coating contacting the housing may be applied.

EFFECT: increased operation life of the laser spark plugs by preventing contamination of the optics and the laser beam outlet.

4 cl, 6 dwg

Description

The invention relates to igniters - spark plugs, in particular laser ones with an integrated prechamber, which can significantly improve the efficiency of spreading the ignition flame and the efficiency of burning the air-fuel mixture due to the simultaneous use of a powerful electric field for fuel assembly ignition of the laser beam and heating and activation of the fuel-air mixture. The invention can find application when used in an internal combustion engine - ICE as carburetor, as well as injection and diesel, as well as in rotary engines, gas piston and other types of engines and in power plants.

State of the art

Usually, the lateral grounded electrode of the electric spark plug is bent and L-shaped, being perpendicular to the direction of the axial central electrode so that the cross section of the discharge part, the so-called "minicamera", facing the axial central electrode, is rectangular.

When a spark discharge occurs, the spark appears between the axial central electrode and the end discharge part of the grounded electrode located below the axial central electrode. The gas mixture in the spark gap formed by these electrodes is ignited by the spark so that the compressed gas mixture is ignited first in the "minicamera" between the electrodes, and then the horizontally expiring torch ignites the rest of the fuel assembly. In conventional designs, the high gas pressure caused by ignition can be blocked by the end discharge part so that the effect of the propagation of combustion on the air-fuel gas mixture in the combustion chamber is not good enough. And starting the engine at low temperatures generally causes difficulty due to the cooling of the flaming flame from the cold metal parts of the cylinder head.

When the residual carbon (the product of incomplete combustion of the fuel-air mixture - FA) remains in the spark gap between the electrodes, carbon can accumulate and change from the phase of the particles to the phase of the connection on the surfaces of the electrodes so that a short circuit can occur between the electrodes. In this state, even when voltage is applied, a spark may not occur, which leads to serious problems up to stopping the engine or releasing the air-fuel mixture through the exhaust pipe without combustion. When an unburned gas mixture is discharged into the exhaust pipe, a reverse flash effect is often manifested, with an emergency effect and a reduced combustion efficiency. Failure of one of several cylinders can remain unattended for a long time, which will lead to engine failure due to imbalance of rotor parts.

During the operation of the internal combustion engine due to corrosion, cracks may appear at the end of the axial central electrode, which leads to the occurrence of critical damage. Spark plug life may be reduced due to such a defect.

Known electric spark plug according to the patent of the Russian Federation for the invention No. 2366053, IPC Н01Т 13/20, publ. August 27, 2009. This spark plug contains a central electrode and a side electrode of a cylindrical shape, between them a “mini-chamber” is formed. Spark discharge is carried out on a cylindrical wall, and the output of combustion products is carried out in an annular gap.

The disadvantages of this candle are the possible clogging of the annular gap due to the deposition of solid particles of combustion products on both electrodes, especially when working on an enriched mixture.

Known spark plug according to the patent of the Russian Federation for the invention No. 2366052, IPC Н01Т 13/00, publ. August 27, 2009. This candle contains a central electrode and a L-shaped side electrode, the plane of which is twisted along the length to create a vortex motion of the combustion products.

Disadvantage: poor engine starting at low temperatures.

Known laser spark plug according to the patent of the Russian Federation for the invention No. 22576691, IPC F02P 23/04, publ. 01/26/2015, the prototype.

This candle is in a laser spark plug containing a housing, an insulator microchip - a laser installed in a cavity inside the insulator, an optical window, a focusing lens and a target mounted in a prechamber, into which several exit openings enter at an angle.

Disadvantages:

- soot deposition on the optics and the hole for the exit of the laser beam of the laser candle,

- the large required laser power with limited dimensions of the laser spark plug, which it is advisable to produce the dimensions as an exact copy of standard electric spark plugs,

- relatively low completeness of combustion of fuel in the engine cylinder due to its ignition at one point and, as a result, emission of harmful substances in exhaust gases.

The objective of the invention, corresponding to the achieved technical result, is to increase the life of the laser candle by preventing contamination of the optics and the outlet of the laser beam.

The technical result is an increase in the service life of the laser spark plugs by preventing contamination of the optics and the exit hole of the laser beam.

The solution of these problems was achieved in a laser spark plug containing a housing, an insulator, a microchip laser installed in a cavity inside the insulator, an optical window, a focusing lens and a target mounted in a prechamber, into which several exit holes enter at an angle, characterized in that the target is mounted on the central fairing, mounted coaxially with the axis of the laser spark plug, and on the side wall of the central installed twisting blades. The laser candle may contain an additional optical window with a protective cavity between the optical window and the additional optical window. The microchip laser is mounted on a shock absorber. On the insulator from the side of the internal cavity, a metallized coating can be applied in contact with the housing.

The invention is illustrated in the drawings, where

- in FIG. 1 shows an assembly ignition system,

- in FIG. 2 shows a laser spark plug, the first option,

- in FIG. 3 shows a laser spark plug, the second option,

- in FIG. 4 shows the target

- in FIG. 5 shows a section aa,

- in FIG. 6 shows a diagram of the protection of optics from foreign particles.

The laser spark plug (Fig. 1) contains a housing 1 (metal), an insulator 2, in the inner cavity 3 of which a microchip laser 4 is installed, an internal high-voltage wire 5 connects it to the terminal tip 6.

The microchip laser 4 is installed in the inner cavity 3 on the shock absorber 7, a vacuum tube 8 is attached to it. The vacuum tube 8 is a metal and ceramic tube inside which a vacuum is created. At the opposite end 9 of the vacuum tube 8, a focusing lens 10 is fixed.

An optical window 11 and an additional optical window 12 with a protective cavity 13 between them are mounted under the focusing lens 10.

Under the additional optical window 12, a washer 14 is installed with an opening 15 for the exit of the laser beam 16, and under the washer 14 a prechamber 17 is made in the form of a cylindrical cavity 18, which passes into the cavity 19 in the form of a truncated cone. The cavity 19 is limited by the end bottom 20, the conical wall 21 and the cylindrical wall 22. Outlets 23 are made in the conical wall 21 (Figs. 1 ... 4).

To supply energy to the microchip laser 4, a metallized coating 24 is provided on the inner surface of the insulator 2 and a contact 25 on the shock absorber 7 from the inside.

The laser spark plug is screwed into the cylinder head 26 through a thread 27. The cylinder head 26 is connected to a ground wire 28 to ground 29.

The laser candle has in the cylindrical cavity 18 of the prechamber 17 a target 30 for the laser beam 16 (Fig. 3 ... 6). The target 30 is mounted on the central fairing 31, on the lateral surface of which are installed twisting blades 32.

In this case, the laser spark plug can be made in one of two options, depending on the mounting of the central fairing (Fig. 2 and 3).

In FIG. 2 shows a prechamber 17 in which a central fairing 31 is installed, which, with the aid of a cylindrical holder 33, is mounted on the end face 20.

In FIG. 3 shows a prechamber 17, in which a central cowl 31 is mounted on radial holders 34 on a cylindrical wall 22.

In FIG. 4 shows a fragment of the prechamber 17 with the target 30, and in FIG. 5 section BB.

In FIG. 6 shows a diagram of the protection of optics from foreign particles 35.

Device operation

When a laser spark plug is used, for example, as part of an internal combustion engine - ICE (Fig. 1 ... 6), which includes this spark plug, the engine is started by a starter (not shown). After injection of the fuel assembly (air-fuel mixture), part of it through the outlet 23 enters the pre-chamber 17. At the time of ignition timing, a distributor (not shown) supplies the potential to the tip 6 and then to the microchip laser 4, which generates laser radiation. Laser radiation through a vacuum tube 8 is transmitted to a focusing lens 10, which creates a laser beam 16. The laser beam 16 passes through the optical windows 11 and 12 and the hole 15 of the washer 14 and focuses on the target 30. The target 30 is very small and heats up almost instantly to a temperature above 1000 ° C. A fuel assembly in contact with the target 30 ignites and the flame front in the form of a ball, the flame front radially goes to the outlet openings 23 and exits from them into the combustion chamber of the engine cylinder.

In the “stroke” cycle, the combustion products having a very high temperature are ejected with great speed from the pre-chamber 17 into the cavity of the combustion chamber of the internal combustion engine cylinder and ignite the entire fuel assembly charge present in it.

In the intake mode of the fuel assembly into the combustion chamber, part of the fuel assembly (5 ... 7%) enters the chamber 17 and its main part, passing through the spinning blades 32, is twisted. Due to this, foreign particles 35 (unburned carbon) are discarded to the periphery and the hole 15 in the washer 14 is not clogged.

Such an organization of the fuel assembly ignition process will provide 100% ignition even in the worst conditions at low temperature and high humidity at low power of the laser microchip 4 (Fig. 1). Also, this approach can be applied on engines operating on cryogenic fuels: hydrogen and liquefied natural gas. To ignite a cryogenic fuel having a very low temperature, it is not necessary to significantly increase the power of the spark plug. This effect will be especially well manifested on high power engines and on engines running on natural gas.

As a result, the use of the group of inventions will allow the following.

1. To prevent the deposition of foreign parts (soot) on the focusing lens and in the hole for the exit of the laser beam and thereby significantly extend the life of the laser spark plug.

2. Reduce the overall dimensions of the laser spark plug to the dimensions of standard electric spark plugs.

3. Reduce the required laser power through the use of preheating of fuel assemblies.

4. Simplify the design of the ignition system by reducing the number of parts when combining a laser spark plug and a prechamber.

5. Improve ignition when starting an unheated engine, especially at low temperatures, by igniting the fuel assembly in a small volume of the prechamber with two laser and pre-heated electric field energy sources.

7. Reduce fuel consumption due to its more complete combustion, provided more accurate ignition of the fuel assemblies in the combustion chamber of the internal combustion engine with a powerful prechamber torch.

8. Reduce the emission of harmful substances due to more complete combustion of the fuel.

Claims (4)

1. Laser spark plug containing a housing, an insulator, a microchip laser installed in a cavity inside the insulator, an optical window, a focusing lens and a target mounted in a prechamber, which includes several exit openings at an angle, characterized in that the target is mounted on a central fairing mounted coaxially with the axis of the laser spark plug, and spinning blades are mounted on the side wall of the central cowl. 2. The laser spark plug according to claim 1, characterized in that it contains an additional optical window with a protective cavity between the optical window and the additional optical window. 3. The laser spark plug according to claim 1 or 2, characterized in that the microchip laser is mounted on a shock absorber. 4. The laser spark plug according to claim 1 or 2, characterized in that on the insulator from the side of the internal cavity a metallized coating is applied in contact with the housing.

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