RU2649720C1 - Laser spark plug - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: invention relates to laser spark plugs with ignition cell for combustion engines. Essence of the invention consists in that laser spark plug contains a body, an insulator, a microchip laser installed in the cavity inside the insulator, a vacuum tube connected to it, an optical window, a focusing glass, an ignition cell with a cylindrical and conical cavity, washer with a hole between the optical window and ignition cell and target, installed in one of the cavities of the ignition cell on the holder, as well as several outlets entering the conical cavity. In this case, vacuum tube is installed with concentricity error relative to the ignition cell axis, the hole in the washer is also made with concentricity error, and in the cylindrical cavity of the ignition cell on central shaft impeller of the aerodynamic turbine is installed. Laser plug may comprise an additional optical window with a protective cavity between the optical window and an additional optical window. Microchip laser can be installed on a shock absorber. On the insulator, from the side of the inner cavity, a metallized coating may be applied contacting the body. Central shaft of the turbine can be mounted on ceramic bush bearings.

EFFECT: technical result is an increase in the service life of the laser spark plug by preventing contamination of the optics and the laser beam outlet.

5 cl, 5 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 fuel beam with a powerful electric field to ignite the laser beam and heat and activate the air-fuel mixture). The invention can find application when used in internal combustion engines - internal combustion engines, both carbureted and 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, perpendicular to the direction of the axial central electrode so that the cross section of the discharge part, the so-called “mini-chamber”, 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 “mini-chamber” 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 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: a 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, a microchip laser insulator 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 fuel combustion in the engine cylinder due to its ignition at one point and, as a result, the 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, a vacuum tube connected to it, an optical window, a focusing lens, a prechamber with a cylindrical and conical cavities, a washer with a hole between the optical window and a pre-chamber and a target mounted in one of the pre-chamber cavities on the holder, several outlet openings entering the conical cavity, so that the vacuum tube is eccentric with respect to the axis of the pre-chamber s, the hole in the washer is also formed with an eccentricity in the cylindrical cavity of the prechamber is installed on a central shaft impeller wind turbine. The laser candle may contain an additional optical window with a protective cavity between the optical window and the additional optical window. A microchip laser can be 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 central shaft can be mounted on ceramic plain bearings.

The invention is illustrated in FIG. 1 ... 5, where

- in FIG. 1 shows a laser spark plug,

- in FIG. 2 shows a prechamber,

- in FIG. 3 shows the impeller of an aerodynamic turbine,

- in FIG. 4 shows view A,

- in FIG. 5 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. The vacuum tube is eccentric with respect to the longitudinal axis of the laser spark plug. 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. The hole 15 is made with the same eccentricity relative to the axis of the vacuum tube 8, and their axes are aligned.

Under the washer 14, a prechamber 17 is made in the form of a cylindrical cavity 18, turning into a conical cavity 19 in the form of a truncated cone. The conical cavity 19 is limited by the end face 20, the conical wall 21 and the cylindrical wall 22. Outlets 23 are made in the conical wall 22 (Figs. 1 ... 4).

To supply energy to the microchip laser 4 (ground contact), a metallized coating 24 is provided on the inner surface of the insulator 2 and 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 ... 5). The target 30 is mounted on the holder 31. In the cylindrical cavity 18 of the pre-chamber 17 on the central shaft 32, the impeller of the aerodynamic turbine 33 is installed, which has a hub 34 and blades 35.

In FIG. 2 shows the prechamber 17, in which a target 30 is mounted on the holder 31, made in the form of a metal ball of small diameter from 0.5 to 1 mm.

In FIG. 3 shows the impeller of an aerodynamic turbine 33, FIG. 4 - view A. The Central shaft 32 can be installed in bearings 36, which are advisable to perform ceramic.

In FIG. 5 shows a diagram of the protection of the optics and the holes 15 of the washer 16 from foreign particles 37 (carbon).

Device operation

When the laser spark plug, for example, as part of an internal combustion engine - ICE (Fig. 1 ... 5), 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 terminal 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 is ignited, and the flame front in the form of a ball radially goes to the outlet openings 23 and exits from them into the combustion chamber of the engine cylinder (not shown).

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 (10 ... 20%) enters the chamber 17 and its main part, passing through the impeller of the aerodynamic turbine 32, is twisted. Due to this, foreign particles 37 (unburned carbon) are thrown 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 microchip laser 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 a group of inventions will allow:

1. To prevent the deposition of foreign particles (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 (5)

1. A laser spark plug comprising a housing, an insulator, a microchip laser installed in a cavity inside the insulator, a vacuum tube connected to it, an optical window, a focusing lens, a pre-chamber with a cylindrical and conical cavities, a washer with an aperture - between the optical window and the pre-chamber and a target mounted in one of the cavity of the prechamber on the holder, several outlet openings entering the conical cavity, characterized in that the vacuum tube is eccentric with respect to the axis of the prechamber, the hole in the washer t kzhe formed eccentrically in a cylindrical cavity of the prechamber is installed on a central shaft impeller wind turbine. 2. The laser candle 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. 5. The laser spark plug according to claim 1 or 2, characterized in that the central shaft is mounted on ceramic plain bearings.

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