JPS61104580A - Ignition plug - 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 [Field of Industrial Application] The present invention relates to the improvement of a spark plug used in a high-voltage ignition circuit of an internal combustion engine, and more particularly, the present invention relates to an improvement of a spark plug used in a high-voltage ignition circuit of an internal combustion engine. This article relates to improvements in resistors built into.

[Prior Art] High-frequency junction radio waves generated from a spark plug can be suppressed by, for example, using a resistor between a terminal metal fitted to one end of the inner hole of the spark plug and a center electrode fitted to the other end. This can be done by connecting them in series to form a high frequency absorption circuit.

Conventionally, in the above-mentioned resistor, a mixture consisting of carbon, zirconia (or alumina, or (1 magnesia) powder, and glass particles is filled into the inner hole and sintered.
k are known. This is shown in Figure 5.The IJ does not have a structure in which carbon is dispersed in zirconia powder, which is the sea urchin aggregate, and the current path 7'12 is connected to the current path 7'12 by a high-resistance glass Ie + Ryo41. By doing so, the effect of suppressing the noise current (hereinafter, the line of suppressing the noise current ψ by forming the current path 42 in a zigzag shape is referred to as a structural effect) is further enhanced.

However, the above 1. Some resistors made of a sintered body of a mixture of carbon, Zir-1nia powder, and glass particles do not yet have a sufficient effect of suppressing sonic radio waves.

The present invention researched and considered the reason for this, and found that the zirconia powder used above plays a role in filling the gaps that occur in the conductive path, but since zirconia itself has a high melting point, it is difficult for zirconia to seize together. Therefore, we came to the conclusion that it would be difficult to achieve better performance than the current performance due to the small holes remaining in the conductive path, and devised a spark plug with the following configuration.

[Problems to be Solved by the Invention] The present invention has been devised in view of the above-mentioned circumstances, and provides a spark plug with further improved box sound radio wave suppression effect by improving the above-mentioned resistor. It is something.

[Means for Solving the Problems] The present invention provides a resistor for the conventional spark plug as described above.
Glass fine powder is used instead of zirconia powder.

FIG. 1 is a sectional view showing an example of the spark plug of the present invention, and FIG. 2 is a schematic diagram illustrating the structure of a resistor used in the spark plug.

That is, the present invention comprises: an insulator 1 having an inner hole penetrating in the axial direction;
a terminal fitting 2 fitted into a portion of one end of the inner hole of the insulator 1; a center electrode 3 fitted into an opening at the other end of the inner hole of the insulator 1; In the spark plug in which a resistor 4 is disposed in the inner hole and between the terminal fitting 2 and the center electrode 3, the resistor 4 contains at least 4 wt% or less of carbon and the carbon. 9 to 4.0 wt% of glass fine powder with a larger particle size than the glass fine powder, and 60 to 90 wt% of glass particles with a larger particle size than the glass fine powder.
This spark plug is characterized in that it is a sintered body consisting of wt%.

In the spark plug of the present invention, other than the resistor 4 (8-component insulator 1, terminal fitting 2, center electrode 3, etc.), conventional ones can be used as they are.

As shown in FIG. 2, the structure of the resistor 4 consists of high-resistance glass particles 41 (411) and a current path 12 formed around it in a jig shape.
No. 2 is considered to be formed by using fine glass powder as an aggregate and filling it with carbon, which is a conductor.

The particle size of the glass particles 41 (/l1l) is larger than the glass fine powder, and is preferably about 50 μm to 300 μm.

If it is smaller than 50 μm, the glass tends to soften during normal use, making the current path 42 unstable; if it is larger than 300 μm, the resistor 4 may be baked and welded into the inner hole of the insulator 1.
This is because gaps are likely to be formed between the glass particles 41 and the current path 42. Further, the proportion of the glass particles 41 in the resistor 4 is 60 to 90 wt%. This is because if it is less than 5 parts wt%, the above-mentioned structural effect cannot be sufficiently obtained, and if it is more than 90 parts wt%, the resistance of the resistor 4 will be too high and the ignition energy will be insufficient.

A part of the glass particles 41 may be replaced by ferrite particles 412 having a particle size similar to that of the glass particles. This utilizes the high frequency absorption ability of ferrite, and the type of ferrite is not limited. The proportion of ferrite particles in the resistor 4 is desirably 20w1-% or less. 2
If it exceeds 0w1-%, the resistance (the conductivity of A4 becomes too large, the ignition energy) will increase and the fuse will increase.
There are many defects in the conductive path around Lie 1 (it becomes 1 if the durability deteriorates as a result.In addition, in order to reduce the above structural effect by 1q) ■The resistivity of Lies 1 to 412 is 1020 cm or more. is necessary.

The particle size of the fine glass powder considered to be the current path 42 is smaller than the above-mentioned glass particles, and is preferably about 5 μm to 80 μm. 80 tlm
If it is larger than 5 μm, holes will be formed in the current path 42, and if it is smaller than 5 μm, holes will be formed in the current path 42.
This is because 2 becomes unstable.

Particle size fJ of carbon is smaller than the above fine glass powder 0
．． The thickness is preferably about 5 ttm to 3 μm. Further, it is desirable that the proportion of the resistor 4 in the resistor 4 is 4 w 1-% or less. This is because the resistance of the resistor 4 decreases when the amount exceeds /lIwt%, and the sound suppression effect decreases.

-7- The spark plug of the present invention has a resistor 4 consisting of the above-mentioned components.
It is manufactured by filling the inner hole of the insulator 1 between the terminal fitting 2 and the center electrode 3, and then welding it to the inner wall of the inner hole using a baking iron. Here, the temperature for welding is generally around 900'C.

[Function] The electric field strength of the sonic radio waves from the ignition plug is proportional to the spark discharge current, and the current is applied to the resistor 4 inserted in the ignition circuit.
suppressed by The suppression effect is improved by the structural effect IC due to the glass particles 41 arranged in the resistor 4. Further, it is considered that the glass fine powder used as the aggregate of the current path 712 in place of zirconia is less likely to cause pores in the current path 42. Therefore, the current path 42 is stable. Note that when a portion of the glass particles 41 is replaced with ferrite particles 412, the noise suppression effect is further improved due to the high frequency absorption ability of the ferrite 1.

[Example] The present invention will be explained below based on specific examples.

(a) Production of products Example products A and B and comparative product C were produced using the following procedure. The shape of each product was J-shaped as shown in FIG.

(1) Preparation of resistor raw materials Prepare each resistor raw material (samples Δ, B, 'C) for each product Δ, BIC at each ratio shown in Table 1.

For example, to explain the details of the preparation for sample △, first, carbon and lithium calcium borosilicate glass (fine glass powder) were put through a 200 mesh sieve, and the material that passed the sieve was dry-processed using a vibrating mill. crush,
To this, add lithium calcium borosilicate glass (glass particles) that has passed a 40 meter full ray and fly 1 that has passed a 32 meter sieve, and add this to dex]
~ It was mixed with an aqueous solution of phosphorus and CMC, then dried, and passed through a 24-mesh sieve.The sample was designated as △. As the ferrite, six types of ferrite shown in Table 2 were used at around 1000℃ - 1o---
-- The material was sintered and then crushed.

(2) For baking of the resistor, samples Δ, B, and C prepared in the above (1) are filled and baked into the inner hole of the insulator 1 shown in Fig. 1, and the spark plugs A,
B and C were produced respectively.

That is, first, the center electrode 3 is inserted into the lower end of the inner hole of the insulator 1, and a glass (SiOz 64wt%, A12036
Copper glass prepared by mixing wt%, B 20323wt%, Naz07wt%) and copper powder in a ratio of 1=1 was placed at a pitch of 0.260, and then heated at 250ko using a φ4.75 push bottle.
After drying, the above resistor raw material 0.59% was filled and pressurized twice, and then the same copper glass as above was added on top of it.
Place Q and pressurize at 200 kq using the stem. In this state, it is placed in a furnace at 870℃ for 30 minutes and heated to form copper glass and glass (glass fine powder, glass particles) in the resistor raw material.
After avoiding softening, the stem was taken out from the furnace J, and the stem was immediately pressurized at 60 kO. Through these operations, the resistor raw materials (samples A and BXC) were formed into the resistor 4, and the copper glass was formed into the copper glass electrodes 51 and 52, respectively. Further, the resistance value of the resistor 4 was set to be the resistance (li) specified in the JIS standard.

After the insulator 1 has been cooled, a housing 6 to which an installed electrode 8 is fixed is attached to the outer periphery of the P3R body 1, and spark plugs A1B and C having the structure shown in FIG.
.

(b) Evaluation I-Note! ! The noise electric field strength of each manufactured product was measured to evaluate the noise suppression effect. The results are shown in FIG.

To measure the electric field strength, each spark plug was placed under 4 atmospheres, which is the same atmospheric pressure as inside the engine, as shown in Figure 4.
After performing discharge aging for several minutes at a rotational speed of 200 rpm, the noise electric field strength at each frequency was measured using a noise measuring device. Note that the measured value was the maximum value of the noise electric field strength at each frequency.

As can be seen from FIG. 3, the noise electric field strength of the product A1B according to the embodiment of the present invention is significantly reduced at each frequency compared to the conventional product C. This is thought to be because fine glass powder was used instead of zirconia as the aggregate of the current path 42, so the number of pores was reduced compared to the conventional case. Further, in comparing the products of the embodiments of the present invention, product A has a smaller noise electric field strength than product B. This may be due to the effect of mixing ferrite particles into the resistor 4.

[Effects of the Invention] In summary, the present invention uses a sawtooth spark plug with a resistor inserted therein, in which carbon, fine glass powder, and glass particles are sintered (-welded).

As is clear from the description of the examples, the current path of the resistor for suppressing the 4.19 fl sound current in the ignition plug of the present invention is made by using fine glass powder instead of the conventional zirconia powder. It is made up of aggregate with carbon dispersed in it. Therefore, stability 4+1 and noise suppression effect are improved.

Furthermore, high-resistance glass particles and, in some cases, ferrite particles having the same particle size as the glass particles are arranged in the resistor. Therefore, the current path becomes a zigzag shape, and the above-mentioned structural effect is obtained.

Moreover, when a part of the glass particles are replaced with particles in the Ferrite 1, the noise suppression effect is further improved due to the high frequency absorption ability of the 7-piece light and the effect of reducing voids in the current path due to the glass fine powder.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the structure of the spark plug of the present invention, and FIG. 2 is a schematic diagram illustrating the structure of a resistor used in the spark plug. FIG. 3 is a graph showing the measurement results of the noise electric field strength of the products A and B according to the embodiments of the present invention and the conventional product C. FIG. 4 is an explanatory diagram of a method for measuring noise electric field strength. FIG. 5 is a schematic diagram illustrating the structure of a resistor of a conventional spark plug. 1... Insulator 2... Terminal fitting 3...
Center electrode 4...Resistor 41.411...
Glass particles 412... Ferrite particles 42... Current path

Claims (5)

[Claims] (1) An insulator having an inner hole penetrating in the axial direction, a terminal fitting fitted into an opening at one end of the inner hole of the insulator, and an opening at the other end of the inner hole of the insulator. and a resistor disposed within the inner hole of the insulator and between the terminal fitting and the center electrode, the resistor comprising at least , 4 wt% or less of carbon, 9 to 40 wt% of glass fine powder having a larger particle size than the carbon, and 60 to 90 wt% of glass particles having a larger particle size than the glass fine powder.
A spark plug characterized in that it is a sintered body consisting of %. (2) The spark plug according to claim 1, wherein 20 wt % or less of the glass particles are replaced with ferrite particles having the same particle size as the glass particles. (3) The resistor has a structure in which a current path in which carbon is dispersed in the glass fine powder is formed around the glass particles and ferrite particles.
Spark plugs listed in section. (4) The spark plug according to claim 1, wherein the particle size of the glass fine powder is within the range of 5 to 80 μm. (5) The spark plug according to claim 1, wherein the glass particles have a particle size within a range of 50 to 300 μm.