JPS59173986A - Ignition plug for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spark plug for a spark-ignition internal combustion engine used in vehicles such as automobiles, and particularly to a spark plug suitable as a spark plug for a spark-ignition internal combustion engine with direct fuel injection. It depends.

In an in-cylinder combustion single-injection spark ignition internal combustion engine, fuel is directly injected into the combustion chamber from a fuel injection nozzle, and the mixture of fuel and air is ignited by a spark using a spark discharge means such as a spark plug to cause combustion. This internal combustion engine is a type of internal combustion engine called a stratified charge engine or a stratified combustion engine. In this type of internal combustion engine, as long as there is an air-fuel mixture with an appropriate flammable air-fuel ratio near the spark discharge point, even if the air-fuel mixture existing in other parts has an air-fuel ratio other than the appropriate flammable air-fuel ratio, In other words, it performs good combustion by spark ignition even in a heterogeneous mixture, and is excellent in fuel economy, gas performance, and high combustion resistance. Various studies have been conducted and various proposals have been made.

One of the challenges in putting the above-mentioned in-cylinder fuel injection spark ignition internal combustion engine into practical use as an internal combustion engine for automobiles is ensuring combustion by reliable spark ignition in the entire operating range. There is still no known reliable in-cylinder fuel injection spark ignition internal combustion engine that completely solves the problem. In-cylinder fuel injection type spark ignition internal combustion engines create a mixture of combustible air-fuel ratio near the spark discharge point of the spark discharge means by matching the swirling flow of intake air generated in the combustion chamber with the spray characteristics of the fuel injected from the fuel injection nozzle. However, the position of this region changes as the strength and flow velocity of the intake swirl flow changes with changes in engine speed, and for this reason, this in-cylinder fuel injection When a type spark ignition internal combustion engine is used as an internal combustion engine for an automobile with a relatively high normal rotational speed, the spark discharge gap of the spark discharge means in which the area covered by the presence of a combustible air-fuel mixture with the proper air-fuel ratio is fixed. As a result, the spark ignition of the air-fuel mixture is not performed stably and well, and as a result, the internal combustion engine has good stratified combustion only in a specific operating range.

The same applicant as the present applicant took into account that the position of the region where a mixture with a suitable flammable air-fuel ratio exists fluctuates as the engine speed changes, and spark discharge gaps are arranged at multiple positions in the direction of the fluctuation. A spark-ignition internal combustion engine with in-cylinder fuel injection was proposed in Japanese Patent Application No. 1983 (filed on March 22, 1988). In this in-cylinder fuel injection type spark ignition internal combustion engine, even if the position of the region where a combustible air-fuel mixture exists at the appropriate air-fuel ratio changes in response to changes in the flow velocity of the intake swirl flow, that region is always located within the plurality of above-mentioned By including at least one large seedling discharge gap in each position, the spark ignition of the air-fuel mixture is reliably performed by the emission of a spark in any spark discharge gap, resulting in good performance over the entire operating range. Stratified combustion occurs.

The object of the present invention is to provide a multi-point spark plug suitable as a spark discharge means for an in-cylinder fuel injection type spark ignition internal combustion engine, which was proposed in Japanese Patent Application No. 1983.

Such an object, according to the invention, is to provide a center electrode, a ground electrode, and at least two spark discharge gaps between said center electrode and said ground electrode in electrically advantageous positions. This is achieved by a spark plug for an internal combustion engine having an intermediate electrode and the like.

The invention will now be explained in more detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing the main parts of an embodiment of a direct fuel injection type spark ignition internal combustion engine equipped with a spark plug according to the present invention. In Fig. 1, 1 and 2 respectively indicate a cylinder head and a cylinder block that constitute the engine body of a direct fuel injection type spark ignition internal combustion engine, and these are connected to each other via gaskets 1 to 3. There is.

A cylinder liner 4 is attached to the cylinder block 2, and the cylinder liner has an inner cylinder bore 5.
A piston 6 is received therein so as to be able to reciprocate in the vertical direction as shown in the figure.

The cylinder head 1 is provided with a vortex chamber 7.

The vortex chamber 7 includes a hemispherical spherical ceiling 8 directly provided by a recess formed in the cylinder head 1, and a nozzle member 10 fitted into a mounting hole 9 of the cylinder head 1 and fixed to the cylinder head. It is a comet-shaped vortex chamber that communicates with the cylinder bore 5 through a communication hole 12 formed in the nozzle member 10 and inclined with respect to the cylinder axis. The intake air inside the cylinder bore 5 flows through the communication hole 1 due to the upper back.
By flowing in through 2, a vertical intake swirl flow S flowing along the inner wall is generated.

The cylinder block 1 is provided with a nozzle mounting hole 13 that opens in the ceiling of the vortex chamber 7, and a nozzle 14 is screwed into the nozzle mounting hole. ing. The fuel injection nozzle 14 is, for example, a bottle type, and is installed in the cylinder head 1 with an inclination in the same direction as the communication hole 12, and has a fuel injection port 15 at its tip. Gasoline, alcohol, or other liquid fuel is injected and supplied from the fuel amount 1] into the vortex chamber 7 through the injection hole 16 in a direction across the intake swirl flow S generated in the vortex chamber at a predetermined spray diffusion angle. ing.

Liquid fuel stored in a fuel tank 17 is supplied to the fuel injection nozzle 14 via a fuel conduit 18, a fuel pump 19, a fuel conduit 2o, a fuel injection cylinder y'21, and a fuel conduit 22. .

The fuel injection pump 21 may have substantially the same structure as a general fuel injection pump used in a diesel engine, and measures the amount of fuel per stroke according to the engine load, and measures the amount of fuel per stroke according to the engine load. Fuel is supplied to the fuel injection nozzle 14 at high pressure.

The cylinder head 1 is provided with a plug hole 23 that opens in the ceiling of the vortex chamber 7.
A spark plug 24 according to the present invention is screwed into the hole 614.
is being pulled. .

A spark plug 24 according to the present invention is best shown in FIG. The spark plug 24 includes a center electrode 2 attached to an electrically insulating member, such as an electrically insulating member 25 made of ceramics.
6, a high-voltage power supply shaft 2 which is attached to the electrically insulating part 1, has one end conductively connected to the center electrode 26 via a conductive sealing member 27, and has a high-voltage terminal 28 attached to the other end. A cylindrical metal plug body 32 having a threaded part 30 and a hexagonal nut part 31 on the outer periphery, a ground electrode 33 taken in the plug body, and fixed to the electrically insulating member 25. Two intermediate electrodes 35 and 36 with different leg lengths are respectively attached to the metal ring 37, and the center electrode 26 and the intermediate electrode 35 are spaced at a predetermined distance at their tips. The ground electrode 33 and the intermediate electrode 3G face each other at a predetermined interval 43 at their tips, and a spark discharge gap 38 is formed in the opposing part. It constitutes a spark discharge socket 39. That is, the spark plug 25 has two spark discharge knobs 38 and 39 that are electrically connected in series and are spaced apart from each other in the axial direction of the intermediate electrode 2G.

When the spark plug 24 is properly installed in the cylinder 1 as shown in FIG. The spark discharge gap 39 is relatively thicker (separated from the inner wall of the spherical part 8, and the spark discharge gap 39 is located at a distance from the inner wall of the spherical lunar part 8). The gap 3G is not far away from the inner wall of the spherical ceiling portion 8, but is located very close to the inner wall.

Between the center electrode 26 of the spark plug 24 and the ground electrode 33←
Second, a high voltage is selectively applied to the ignition coil 40 induced by the ignition coil 40.

When a high voltage is applied between the center electrode 26 and the ground electrode 33, the spark plug 2/I first closes the spark discharge gap 38.
Dielectric breakdown occurs in this gap 38, causing a spark discharge, and the center mold 4@26 and the intermediate electrode 35 become electrically connected. Next, dielectric breakdown occurs in the three spark discharge gaps, causing a spark discharge. A 3° ignition coil 40G that generates a spark discharge in the gap 39: It is designed to intermittently induce conductive conductivity when a 1-rega or pulsed <T times the amount is applied from the L-event generator 41, and the igniter coil 40G generates a spark discharge in the gap 39. 4
1 is a top dead center sensor provided opposite the top dead center detection disk 42'. 3, an electric signal related to the piston phase is sent to the crank angle by a crank angle sensor 45 provided opposite to the crank angle detection disc 44. They are each given an electric signal, and output the electric signal to the ignition coil/IO at a predetermined crank angle.

Next, the operation of the spark plug, the behavior of the fuel spray injected from the fuel injection nozzle, and the positional relationship of the spark discharge gap of the spark plug will be explained with reference to FIGS. 3 and 4. FIG. 3 shows a state when the engine speed is below a predetermined value and is relatively low. When the engine speed is relatively low, the moving speed of the piston 6 is not very fast, so the intake air swirl flow is not very fast. The fuel spray is not substantially flown by the intake swirl flow S, and the fuel spray is spread out in a circular shape around the main fuel injection axis Δ of the fuel injection nozzle 14. At this time, a combustible air-fuel mixture with an appropriate air-fuel ratio is formed by mixing the fuel spray with the air surrounding it, and this combustible air-fuel mixture with an appropriate air-fuel ratio exists in the outer peripheral region of the bundle of fuel sprays. There is a spark discharge gap 39 of the ignition plug 24 in the region where the air-fuel mixture with the appropriate flammable air-fuel ratio exists, and therefore, at this time, the spark that occurs in the air-fuel mixture with the appropriate flammable air-fuel ratio [J spark discharge: 1° yap 39] It is ignited by an electrical discharge.

FIG. 4 shows a state when the engine speed is above a predetermined value and is relatively high. Since the moving speed of the piston 6 increases as the engine speed increases, the flow velocity of the intake swirl flow S in the swirl chamber 7 increases accordingly, and the fuel spray injected from the fuel nozzle 15 is caused by this intake swirl flow. The fuel spray bundle is biased toward the fuel injection main axis Δ of the fuel 1111114 nozzle 14, and the combustible II-air-fuel mixture is formed by mixing the fuel spray with the air around it. As the engine speed increases, the area where the mixture exists moves toward the inner wall of the ceiling of the vortex chamber 7. Therefore, when the engine speed is above a predetermined value, the ignition is activated. The positions of the three spark discharge sockets of the plug 24 are outside the region where a combustible air-fuel mixture exists, and this region includes another spark discharge socket 38 of the spark plug 24. Therefore, at this time, the spark discharge cap is removed. 38
Ignition of the air-fuel mixture having the appropriate combustible air-fuel ratio occurs due to the spark discharge generated.

Above) As shown in the book, if the spark plug according to the present invention is used, spark discharge will occur at the two electric gear A knobs located at different positions, and this will cause the internal combustion engine to operate over its entire operating range. Stable, minute combustion is performed without causing misfires.

FIG. 5 is a longitudinal sectional view showing the main parts of an in-cylinder fuel injection type spark ignition internal combustion engine equipped with another embodiment of the spark plug according to the present invention.

FIG. 6 is a longitudinal sectional view showing the ignition book used in the embodiment shown in FIG.

In addition, in FIGS. 5 and 6, parts corresponding to and overlapping with those in FIGS. 1 and 2 are indicated by the same reference numerals as those in FIGS. 1 and 2. In the embodiment, a center electrode tip member 26a supported by an electrically insulating member 25 is attached to the tip of the center electrode 26.
J. An intermediate electrode 51 is attached to the electrically insulating member 25. The intermediate electrode 51 is connected to the center electrode tip member 2 at one end.
It faces one end of the ground electrode 33 at a predetermined interval, and forms a spark discharge gear X/tube 38 between it and the center electrode tip member. The electrodes face each other with an interval of , and form another three spark discharge gaps between them and the ground electrode.

In this embodiment as well, the spark plug 5o has two spark discharge gaps 38 and 139 that are electrically in series with each other and spaced apart from each other in a direction parallel to the axis of the center electrode 2G. A high voltage is applied between the center electrode 2G and the ground 1' pole 33, thereby causing a spark discharge in each of the two spark discharge gaps 338 and 39.
ing.

When the spark plug 50 is properly attached to the cylinder rod 1 as shown in FIG.
11. The Ti gaps 38 and 39 are both located in front of the fuel injection flow from the fuel q/j nozzles 14 and are biased to one side from the fuel injection main axis, and the spark discharge r
The gap 39 is located at a relatively large distance from the inner wall of the spherical ceiling part 8, whereas the other spark discharge gap 38 is not far apart from the inner wall of the spherical ceiling part 8 and is very close to the inner wall of the child. It is located in the same position.

Therefore, it will be understood that this embodiment also has the same functions and effects as the embodiments described above.

7 to 9 show another embodiment of the spark plug according to the present invention. Furthermore, in Figures 7 to 9,
The parts corresponding to FIG. 2 are shown in FIG. 2. 1. : Indicated by the same symbol as the symbol. In such embodiments,
The spark plug 55 is attached to the electrically insulating part (Δ255) (=J).
Then, the intermediate electrode 56 connects to the center electrode 2 at one end thereof.
A spark discharge gap 60 is provided between the tips of the intermediate electrodes 57 and 58, and a spark discharge gap 61 is provided between the mutually opposing ends of the intermediate electrodes 57 and 58.The intermediate electrodes 5 have a ground electrode 33 at one end thereof. A spark discharge socket 62 is formed between the tip end portion of each of the spark discharge sockets 62. The intermediate electrodes 56 and 57 are connected to each other by a conductive member 63 provided in the electrically insulating member 25 at both ends thereof. The 81 electric members 6/l I and 2 provided in the electric insulating member 2j5 at both ground ends are conductively connected to each other. That is, the large plugs 55 are electrically connected to each other in a mating relationship. = some 3″-] spark discharge gap 6
0,61.62 are spaced apart from each other in the axial direction of the center electrode 20.

When a high voltage is applied between the center ty pole 26 and the ground electrode 33, the spark plug 55 generates three spark discharge gears ↑ and lug 6.
Spark discharge occurs sequentially at 0.61.62.

Figures 10 and 11 show an embodiment of the spark plug according to the present invention in a single-chamber type in-cylinder combustion type lit injection type spark ignition internal combustion that does not have a subchamber; . In FIGS. 10 and 11, 70 indicates the cylinder head,
Reference numeral 71 indicates a cylinder block, and 72 indicates a piston. The piston 72 has a combustion chamber recess 73 having a circular flat cross-sectional shape at the top thereof. The cylinder head 70 is provided with an intake boat 74 and an air intake boat 75, and the intake air flow drawn into the combustion chamber from the intake boat 74, that is, the intake air swirl, causes the inside of the combustion chamber recess 73 to flow as shown by the arrow in FIG. It is arranged so that an intake swirl flow S as shown in FIG.

A fuel injection nozzle 76 is attached to the cylinder head 70. The fuel injection nozzle 76 is of a hole type, for example, and has a fuel injection lower 7 at its tip, and a piston 72.
When the engine is near the top dead center position, liquid fuel is directed into the combustion chamber recess 73 in a direction that crosses the intake swirl flow S@ generated within the combustion chamber recess.

A spark plug 24, which is the same as the spark plug shown in FIG. 2, is installed in the cylinder head 70.

The spark plug 24 has two spark discharge gaps 138 and 339.
and are electrically connected in series at different positions, and the spark plug is connected to the cylinder block 7 as shown in the figure.
0, the spark discharge gaps 38 and 39 are located in front of the fuel injection flow from the fuel injection nozzle 76, and the spark discharge gap 39 is located closer to the inner wall of the combustion chamber recess 73. The spark discharge gap 38, on the other hand, is located close to the inner wall.

The flow velocity of the intake swirl flow S generated in the combustion chamber recess 73 increases as the intake flow velocity increases as the engine speed increases. Therefore, in this embodiment as well, fuel injection increases as the flow velocity of the intake swirl flow increases. The fuel spray bundle injected from the nozzle 7G is flowed toward the inner wall of the combustion chamber recess 73 by the intake swirl flow, and a suitable combustible air is obtained by mixing the fuel spray with the air existing around it. As the engine speed increases, the region where the mixture of fuel ratios exists is displaced from the fuel injection main axis Δ of the fuel injection nozzle 76 in a direction closer to one inner wall portion of the combustion chamber recess 73.

Therefore, when the engine speed is relatively low, there is a region where the air-fuel mixture with the appropriate combustible air-fuel ratio exists near the spark discharge gap 39, and at this time, the spark f11. The air-fuel mixture is ignited by the spark discharge generated in the electric guitar T-tube 39. On the other hand, when the engine speed is relatively high, the ￥4 region where a mixture with a proper combustible air-fuel ratio exists is located outside the spark discharge gap 39 and at the other spark discharge gap 38. Therefore, at this time, the spark discharge generated at the spark discharge gear V-tube 38 ignites the air-fuel mixture (A). Therefore, in this embodiment as well, the internal combustion engine performs good stratified combustion over its entire operating range.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to these embodiments, and it is understood that various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of drawings]

Fig. 1 is a vertical 111i side view showing two embodiments of the pre-chamber type in-cylinder fuel injection type spark ignition internal combustion (Ozeki) in which the spark plug according to the present invention is used; FIGS. 3 and 4 are vertical cross-sectional views showing one embodiment of a spark plug according to the invention, which are shown in FIG. FIG. 5 is a vertical sectional view showing the main parts of an in-cylinder combustion single-injection spark ignition internal combustion engine equipped with another embodiment of the spark plug according to the present invention. FIG. 6 is a longitudinal sectional view showing a spark plug used in the embodiment shown in FIG. 5, and FIG. 7 is a longitudinal sectional view showing another embodiment of the spark plug according to the present invention. Figure 8 is a bottom view of the spark plug shown in Figure 7, viewed from the electrode side;
Figure 9 t to Figure 7 line IX-IXL cross-sectional view, 1st
Figure 0 (The spark plug according to the present invention is used in a single-chamber cylinder internal combustion
FIG. 11 is a vertical cross-sectional view of the main parts of one embodiment used in an il-injection spark ignition internal combustion engine, and FIG. 11 is an i-plane view τ taken along line 1-XI in FIG. 10. 1... Schilling spatula l~, 2... cylinder block. 3... Gasket i, /4... Cylinder liner, 5.
... Schilling bore, 6... Screw 1 Hen, 7... Vortex chamber, 8... Spherical large moon part, 9... Hole, 10...
Nozzle member, 11... Flat bottom, 12... Communication hole, 1
3... Nozzle handle (= J hole, 14... Fuel injection nozzle, 15... Fuel injection port, 16... Ill injection hole, 1
7... Fuel tank, 18... Combustion 1 conduit, 19...
・Fuel pump, 20... Fuel conduit, 21... Fuel injection pump, 22... Fuel 11 conduit, 23... Plug mounting hole, 24... Spark plug, 25... Electrical insulation member , 26... Center electrode, 27... Conductive sealing member,
28...High voltage terminals, 2...High voltage power supply shaft, 30...
...Mounting screw part, 31...Hexagonal note part, 32...
・Metal plug body, 33...Ground electrode, 35.36...
・Intermediate electrode, 37...Metal ring, 38.39...
・Spark discharge gap, 40...Spark plug, 41...
・Igniter, 42...Top dead center detection disc, 43...
・"Two dead center sensor, 44...Crank angle detection disc,
45... Crank angle sensor, 50... Spark plug,
51... Intermediate electrode, 55... Spark plug, 56-5
9... Intermediate electrode, 60--62... Spark discharge gap, 63.64... Conductive member, 70 shilling head, 71... 10 shillings, 72... Piston, 73...・Combustion chamber recess, 7/I...Intake bow 1-
. 75... Lively Bo 1~, 76... Fuel Injection Nozzle, 77... Fuel Injection 1] Special Edition Applicant To] Ta Jidosha Co., Ltd.
Attorney Patent Attorney Akari Masatake No. 1 Figure 4.1 Figure 2 Figure 67 East Figure 7 Figure 8 Figure 9 Figure 3 Figure 1 Figure 1 Figure 4 Figure 5

Claims (1)

[Claims] An ignition for an internal combustion engine having a center electrode, a ground electrode, and an intermediate electrode forming at least two spark discharge gaps electrically in series and at different positions between the center electrode and the ground electrode. plug.