RU2552712C1 - System of fuel and air mixture ignition, spark plug and method of fuel and air mixture ignition - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: group of inventions relates to power machines and may find application in transport and heat power engineering. In a system of fuel and air mixture ignition, comprising a spark plug with central and side electrodes and an insulator, a source of energy connected by low-voltage wires to a high-voltage unit, an ignition distributor, the outlet from which by a high-voltage wire is connected to the upper part of the central electrode, inside the insulator the additional electrode stretches, being electrically connected, via an electroconductive bushing with a central electrode in its lower part, connected by a wire with a source of energy via a switch and a time relay. Also a spark plug and a method of ignition are proposed.

EFFECT: increased efficiency of a spark discharge for reduction of fuel consumption and emission of hazardous substances and increased reliability of ignition.

7 cl, 25 dwg

Description

The invention relates to spark plugs, in particular to an improved spark plug, which can significantly improve the efficiency of distribution of the spark and the efficiency of fuel combustion when used in an internal combustion engine - internal combustion engine, 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 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 spark plug according to the patent of the Russian Federation for the invention No. 2366053, IPC H01T 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 disadvantage of this candle is 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 invention No. 2366052, IPC H01T 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.

The disadvantage is poor engine starting at low temperatures.

Known spark plug according to the patent of the Russian Federation for the invention No. 2360342, IPC H01T 13/54, publ. 06/27/2009

This candle contains a central and side electrodes and two prechambers mounted in series.

Disadvantages: constructive complexity of the candle, its large axial dimensions and high cost.

It is known that for the trouble-free operation of the spark plug, the lower part of the insulator (thermal cone) should have a temperature of about 500-600 ° C. At a temperature lower than indicated on the candle, a layer of soot forms and it begins to work intermittently. The insufficient heating temperature of the insulator and the spark plug electrodes is especially pronounced when the cold engine starts at negative temperatures, when the fuel vapor partially condenses and the ignition reliability of the mixture is due not only to its ionization, but also to the heating of the gas volume adjacent to the electrodes. To increase the reliability of the ignition system in conditions of negative temperatures, candles with forced electric heating are used.

Known, for example, a spark plug containing a metal casing, an insulator and a heating element, placed in an annular groove made on the side wall of the insulator, in its part, closed by a casing according to the USSR AS No. 1802382, IPC H01T 13/00, publ. 1993 year

The disadvantage of this design is that the heating element can be integrated into the candle only during its manufacture. However, the urgent task is the modernization of already made candles.

Also known is a spark plug containing a heating element made in the form of a spiral placed on the thermal cone of the insulator. Such placement of the heating element degrades the electrical characteristics of the plug and can cause a breakdown between the central electrode and the housing, which, in turn, leads to a decrease in the reliability of the plug and skipping sparks (UK application No. 2185529, IPC H01F 13/18, publ. 1987 g.).

It is believed that in spark plugs, the possibility of increasing the spark gap is limited by the breakdown voltage between the central electrode and the housing along the outer surface of the insulator. However, studies have shown that surface breakdown occurs much later in the thickness of the insulator between the central electrode and the flanged edge of the housing. In this section of the insulator, the spark plugs discussed above have a minimum insulator thickness and a minimum distance between the central electrode and the housing.

The basis of the invention is the task of creating a spark plug with electric heating, which allows reliable operation at high breakdown voltage.

The disadvantage is the slow heating of the candle.

Also known is a spark plug with electric heating according to the patent of the Russian Federation for the invention No. 2083042, publ. 06/27/1997

This spark plug for an internal combustion engine contains a metal housing with a flanged edge, an insulator, a part of which is located inside the housing, a central electrode located along the length of the insulator, a side electrode connected to the metal body and forming a spark gap with the central electrode, and a heating element equipped with an annular element of dielectric material mounted on an insulator part located outside the metal housing, the heating element located in an annular element or mounted on a candle under it. The ring-shaped element can be located directly above the flanged edge of the housing and in contact with it. This ensures a decrease in leakage currents in the most stressed area from an electrical point of view. It is also possible to place the ring-shaped element at a certain distance from the edge of the housing, which prevents heat removal from the ring element to the housing. The geometrical dimensions of the ring-shaped element are selected so that the dielectric strength of the insulator in the area of its connection with the housing is equal to or exceeds the minimum strength of the insulator in the area located inside the housing. This allows you to improve the electrical characteristics of the candles and reduce the likelihood of breakdown between the Central electrode and the housing. The placement of the heating element in the annular element is easily feasible from a technological point of view and does not lead to deterioration of the electrical properties of the candle. Ring-shaped elements equipped with heating elements can be mounted on currently commercially available spark plugs.

The disadvantage is the slow and insufficiently effective heating of the candles due to the external location of the electric heater.

As a prototype adopted the spark plug according to the patent of the Russian Federation for the invention No. 2356145, IPC H01T 13/20, publ. 05/20/2009

This spark plug contains an axial central electrode for a spark discharge and a side grounded electrode opposite the axial central electrode relative to the spark gap, with a circular portion in plan having a central circular hole formed at the discharge end of the lateral rounded electrode. In this case, the spark plug includes a plurality of spiral projections that protrude from the inner side of the circular part in the direction of the central circular opening so as to form a turbulent flow in the gas mixture when gas compressed during the compression stroke is supplied into the spark gap through the central circular opening. The technical result is to improve the efficiency of spark propagation by providing better mixing in the spark gap between the electrodes, providing a function of generating a turbulent flow, and also increasing the ignition force.

Signs common with the prototype are an axial central electrode for discharging an ignition spark and a lateral grounded L-shaped electrode, which consists of two parts: conductive and working with a central hole, and the presence of a twisting device. The gap between the electrodes acts as a “mini-camera”, and the central hole plays the role of a nozzle of this “mini-camera”

The disadvantages of the prototype: low efficiency of the spark discharge due to the mismatch of the shape, size and relative position of the electrodes is optimal for an electric discharge in the gas gap. The disadvantage is that the area of the Central hole is made smaller than the cross-sectional area of the Central electrode. This gives several negative results: the twisting device is ineffective and does not perform its function for two reasons:

- spinning means have a very small height (due to the small diameter of the hole) and, being located within the boundary layer of the stream, do not affect the nature of the movement of the bulk of the stream flowing from the hole,

- the spin is carried out in a horizontal plane, which does not contribute to the introduction of the torch into a significant volume of the combustion chamber of the internal combustion engine cylinder, which is usually located below the candle.

In addition, the prototype has several more disadvantages:

- a small diameter hole is more easily clogged by products of incomplete combustion of fuel assemblies,

- the hole acts as the output nozzle of the “mini-camera” and with a small area of the hole, the torch power is insignificant and cannot ensure the start of the internal combustion engine at low temperatures. The role of the second nozzle is played by the lateral gaps between the central and side electrodes, but the combustion products flowing out along the head of the unheated cylinder are sharply cooled and cannot ignite the entire volume of the combustion chamber of the cylinder. The traditionally used method of starting with fuel assembly enrichment leads to excessive fuel consumption, wear of the internal combustion engine piston system and to soot deposition on the electrodes.

The objective of the invention, corresponding to the achieved technical result, is to create a spark plug, which provides more reliable ignition when starting the engine, especially at low temperatures, more complete combustion of the fuel assemblies and the reliability of the spark plug. Thus, the task is to create a candle in which the efficiency of spark propagation is significantly improved by providing better mixing in the spark gap between the electrodes with a spark gap that is much more affecting the efficiency of spark propagation, and with mixing that provides the function of generating turbulent flow. Additionally, the combustion efficiency of the fuel is significantly improved, based on the increased ignition power, such that the removal of residual carbon from the electrodes is effective and the electrodes wear less and more evenly.

The solution of these problems was achieved in the ignition system of the air-fuel mixture, containing a spark plug with a central and side electrodes and an insulator, an energy source connected by low-voltage wires to a high voltage unit, an ignition distributor, the output of which is connected by a high-voltage wire to the upper part of the central electrode, characterized in that inside the insulator an additional electrode passes, electrically connected, for example, through an electrically conductive sleeve with a central electrode in its lower part STI, wired to a power source through a switch and timer.

The solution of these problems was achieved in the spark plug, which includes an axial central electrode for discharging the spark, an insulator and a lateral grounded L-shaped electrode, which consists of two parts: conductive and working with a central hole having a diffuser part, as well as a means for swirling the flow, the fact that according to the invention, an additional electrode is made inside the insulator, connected to a central electrode in its lower part, and the flow swirling means is made on the central electrode. The flow swirl device can be made in the form of a cylinder with blades mounted on the end of the central electrode. The device swirl flow can be made in the form of a recess in the end of the Central electrode. The candle can be made chilled.

Air cooling may be used. A liquid cooling system may be used. The liquid cooling system may comprise a supply manifold, a forward path channel, a middle collector, a reverse path channel and a discharge manifold made in the candle body, and fins are made inside the forward and reverse path channels.

The invention is illustrated in the drawings of FIG. 1 ... 25, where

- in FIG. 1 shows a spark plug in a section,

- in FIG. 2 shows a side electrode with a round hole,

- in FIG. 3 and 4 show a side electrode with an extension and with a triangular hole,

- in FIG. 5 shows a side electrode with a diamond-shaped hole,

- in FIG. 6 shows a side electrode with expansion and thickening,

- in FIG. 7 shows a section aa,

- in FIG. 8 shows a central electrode having an elliptical cross-section,

- in FIG. 9 shows a central electrode with a recess at the end,

- in FIG. 10 shows a central electrode with an annular recess at the end,

- in FIG. 11 shows a central electrode with two recesses,

- in FIG. 12 shows view C,

- in FIG. 13 shows a view of D,

- Fig.14 shows the side electrode, the working surface of which is installed perpendicular to the axis of the Central electrode,

- Fig. 15 shows a central electrode whose end face is made perpendicular to its axis,

- Fig. 16 shows a candle with which, a side electrode, the working surface of which is installed non-perpendicular to the axis of the central electrode, and the central electrode whose end face is made non-perpendicular to its axis,

- Fig.17 shows the Central electrode with a plate of refractory material and a device for swirling the flow on the side generatrix of the plate,

- Fig.18 shows a plate with a device for swirling the flow at the end,

- Fig.19 shows a spark plug with air cooling,

- Fig.20 shows a candle with liquid cooling,

- Fig.21 shows a section B-B ,.

- Fig.22 shows a section C-C,

- Fig.23 shows a section D-D.

- Fig.24 shows a diagram of the movement of fuel assemblies between the electrodes of the candle in the cycle "compression",

- Fig.25 shows a diagram of the movement of combustion products between the electrodes of the candles in the cycle "stroke".

The ignition system (figure 1 ... 25) contains a spark plug, which in turn has a housing 1 with a threaded section 2, a central electrode 3, an insulator 4 and a side electrode 5 connected to the housing 1. The length of the threaded section 2 and its diameter (thread) for each engine its own, but for many types of automobile engines they are unified. The side electrode 5 is L-shaped and consists of a current-supplying part 6 and a working part 7. A gap δ is made between the central electrode 1 and the working part 7 of the side electrode. This gap is strictly regulated for each specific ICE engine and depends on the voltage of the high voltage source and on the ambient temperature. At low temperatures, it is advisable to reduce the gap to facilitate spark breakdown of a relatively cold air-fuel mixture - fuel assemblies.

In the working part 7, a central hole 8 is made against the central electrode 3 (Fig. 1).

The Central hole 8 may be round in shape (figure 2), or triangular (figure 3 and 4), or in the form of a rhombus (figure 5). When making the Central hole 8 in the form of a rhombus, its long diagonal is parallel to the long edges of the working part 7. The Central hole 8 has a diffuser 9 (expanding part).

The optimum angle of the diffuser is 15 ... 30 degrees.

Other versions of the central hole 8 are also possible.

At the central electrode 3, a device for swirling the flow 10 is made (Fig. 9 ... 12). Inside the insulator 4 passes an additional electrode electrically connected, for example, through an electrically conductive sleeve 11 with a central electrode 3 in its lower part 3 (Fig. 1). This is done in order to use the central electrode 3 as a heating element. Heating the central electrode 3 facilitates starting an unheated engine, especially at low ambient temperatures.

The ignition system contains an energy source 13 (battery), a high voltage unit 14 and an ignition distributor 15. An energy source 15 with low voltage wires 16 containing a switch 17 (ignition switch) is connected to a high voltage unit 14. One of the outputs of the energy source 14 is connected to a ground wire 18 with grounding 19 (car body). The output of their ignition distributor 16 by a high-voltage wire 20 is connected to the upper part of the central electrode 3. The switch 17 is multi-contact. An additional wire 21 containing a time relay 22 is connected to one of the contacts, the other end of the additional wire 21 is connected to the additional electrode 11. This electrical circuit is designed to supply low voltage for heating the central electrode of the candle.

On the working part 7 of the side electrode 5, an extension 33 (Fig. 3) can be made in order to make a relatively large central hole 8. In addition, a thickening 24 (Fig. 7) can be made, the thickness of which is determined from the ratio:

H = (1.5-2.5) D2

The diffuser 10 forms an expanding channel for combustion products ignited in the gap between the electrodes 3 and 5. At the same time, it is a tapering channel (accelerating) for the air-fuel mixture in the cycle of its inlet into the ICE cylinder.

A device for swirling the flow 10 (Fig. 9 ... 13) can be performed at the end face 25 of the central electrode 3. There are several possible versions of the device for swirling the flow 10, the simplest is shown in Fig. 9, it is a recess 26 in the form of a hemisphere or ellipsoid rotation. A more effective option, generating paired vortices, can be made in the form of an annular recess 27, forming a Central body 28 (figure 10). An embodiment of two recesses 26 with a central body 28 between them is also possible (Figs. 11 and 13).

The device for swirling 10 gives the flow of combustion products and fuel assemblies the peripheral velocity component in the vertical plane, while vortices are formed. It is possible to create a system of paired vortices rotating in opposite directions. This improves the ignition of the air-fuel mixture.

The use of oval, triangular or in the form of a rhombus central holes 8 in this case will be justified, since a pair of vortex can be placed in the elongated holes.

The working part 7 of the side electrode 5 can be made at an angle α to the end face 25 of the central electrode 3. The optimal value of the angle α = 7 ... 15 deg.

Perhaps, on the contrary, the execution of the plane of the working part 7 of the side electrode 5 is perpendicular to the axis of the central electrode 3, and the end face 25 at an angle β.

The optimal value of the angle β

β = 7 ... 15 deg.

To the working end 25 of the Central electrode 3 can be attached by welding or high-temperature soldering plate 29 of refractory material (Fig.17 and 18).

In this case, the plate 29 can be made cylindrical (Fig. 17) or take the form of a central hole 8. The device for swirling the flow in the form of inclined blades can be located on the side generatrix of the plate made of refractory metal 29 (Fig. 17) or on the end of the plate in the form of a recess (Fig. 18).

In this case, the device for swirling the flow 10 is first performed on the plate 29, and then it is welded (soldered) to the central electrode 3. This, in addition, leads to cheaper spark plugs due to the use of a non-deficient metal for the central electrode 3 and simplification of manufacturing in mass production.

The spark plug can be made cooled. Air cooling may be used. Such a variant of the candle is shown in Fig. 19. Inside the metal (steel) casing 1, a sleeve is made of heat-conducting material 30 (copper or its alloy), on which ribbing 31 is made.

Perhaps the use of liquid cooling systems, which can be performed in different versions. For an example (Fig. 20 ... 23), the simplest design is presented in the form of a lead-in collector 32, a forward channel (s) 33, an average collector 34, a return channel (s) 35 and an outlet manifold 36 made in the housing 1. the outlet collectors 21 and 25, as well as between the channels 21 and 23, have partitions 37 (Figs. 21 and 22) for separating these collectors and channels. In the channel 33 and 35 for the intensification of cooling made ribs 38 (Fig.22). A supply nipple 39 is connected to the inlet manifold 32, and a discharge nipple 40 is connected to the outlet manifold 36. Flexible hoses are connected to the fittings 39 and 40 (not shown in FIGS. 1 ... 25).

24 and 25 respectively show the movement of fuel assemblies and combustion products in the gap between the electrodes 3 and 5 and in the central hole 8 in different cycles of the internal combustion engine.

Device operation

During operation of the internal combustion engine (Fig. 1 ... 25), which includes spark plugs, after fuel assembly injection, a high voltage is applied to the electrodes 3 and 5. In this case, the gap is broken, primarily in the place where it has a minimum value of δ min ( Fig.14). The presence of sharp corners on electrodes 3 and 5 helps to improve the discharge.

The use of devices for swirling the flow 10 will allow you to create a vortex movement of the air-fuel mixture during the compression cycle and combustion products in the cycle "stroke", thereby constantly (for all cycles of the internal combustion engine) to clean the central electrode 3 from soot due to the rotation with high speed of the air-fuel mixture around the central electrode 3 and in the gap. The relatively large size of the Central hole 8 in principle eliminates its clogging with carbon particles and, in addition, throws a more powerful torch to ignite the fuel assemblies in the cylinder.

If an air cooling system is used (Fig. 19), heat is removed by fins 31. The heat flow moves from the combustion chamber of the cylinder (the combustion chamber and the engine cylinder in Figs. 1 ... 25 are not shown) along the housing 1 made of heat-conducting material (steel ), and through the fins 31 is given into the atmosphere.

If a liquid cooling system is used (Fig. 20 ... 23), then the cooling liquid (water or antifreeze) is supplied through the inlet fitting 39 to the inlet manifold 32, then to the forward passage channel 33, then to the middle collector 34, then through the return channels 35 to the output manifold 36 and the output fitting 37 and to the radiator of the liquid cooling system (not shown in FIG. 1 ... 25). The coolant is returned to the liquid cooling system of the spark plug. For multi-piston engines, the ignition systems of all spark plugs can be combined in parallel or in series. This cooling system is more efficient than air cooling, but it is more complex and can be applied on very powerful ICEs.

On Fig shows the movement of the fuel assembly in the gap between the electrodes 3 and 5 and in the Central hole 8 in the cycle "compression". In a conical tapering channel (in the direction of flow) formed by a chamfer 10, the fuel assembly accelerates and twists. All surfaces of the central electrode 3 and the upper surface of the working portion 7 of the side electrode 5 are cleaned of solid carbon deposits.

In the cycle "stroke" (Fig.25), the combustion products having a very high temperature are ejected with great speed from the central hole 8 into the cavity of the cylinder combustion chamber and ignite the entire fuel assembly charge present in it.

Such an organization of the fuel assembly ignition process will provide 100% ignition even in the worst conditions at low temperature and high humidity. 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 good on high power engines.

As a result, the application of the invention will allow:

- improve ignition when starting an unheated engine, especially at low temperatures, by heating the central electrode,

- 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 torch of the so-called "Mini-cameras".

- reduce emissions of harmful substances due to complete combustion of fuel,

- increase the life of the candle by cleaning from soot and preventing the destruction of the Central electrode and through the use of a plate of refractory material,

- use cheaper alloys for the central electrode due to the use of a plate of refractory material at its end,

- significantly increase the life of the candles and eliminate burning of the electrodes through the use of their cooling systems,

- facilitate the manufacturing process of spark plugs for light increasing tolerances for the manufacture of the most critical parts,

- reduce the cost of spark plugs for the reasons mentioned earlier.

Claims (7)

1. The ignition system of the air-fuel mixture, comprising a spark plug with a central and side electrodes and an insulator, an energy source connected by low-voltage wires to a high voltage unit, an ignition distributor, the output of which is connected by a high-voltage wire to the upper part of the central electrode, characterized in that inside the insulator passes an additional electrode electrically connected, for example, through an electrically conductive sleeve with a central electrode in its lower part, connected by a wire to the sources com energy through switch and timer. 2. A spark plug comprising an axial central electrode for discharging a spark, an insulator and a lateral grounded L-shaped electrode, which consists of two parts: conductive and working with a central hole having a diffuser part, as well as a means of swirling the flow, characterized in that an additional electrode is made inside the insulator, connected to the central one in its lower part, and the flow swirling means is made on the central electrode. 3. The spark plug according to claim 2, characterized in that the flow swirl device is made in the form of a cylinder with blades mounted on the end of the central electrode. 4. The spark plug according to claim 2, characterized in that the flow swirl device is made in the form of a recess in the end of the central electrode. 5. The spark plug according to claim 2, characterized in that it is made cooled. 6. The spark plug according to claim 5, characterized in that an air cooling system is used comprising a sleeve of electrically conductive material with fins. 7. The spark plug according to claim 5, characterized in that the liquid cooling system is applied, which comprises a supply manifold, a forward path, a middle collector, a reverse path and a return manifold made in the candle body, and fins are made inside the forward and reverse paths .

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