JPS60180082A - Spark plug for internal combustion engine with sub combustion chamber - 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 This invention provides a sub-combustion chamber with a nozzle arranged in communication with the main combustion chamber, ignites the rich mixture in the sub-combustion chamber, and burns the lean mixture in the main combustion chamber. The present invention relates to an improvement in a spark plug for an internal combustion engine having a chamber.

Conventionally, as shown in FIG. 1, sparks usually fly off in the main spark gear 6 between the center electrode 1 and the ground electrode 5, and the plug gets dirty and conductive substances such as carbon are deposited on the surface of the leg 2a of the insulator 2. When the insulation resistance decreases due to adhesion of substances, a spark is caused to fly into the auxiliary spark gap 7 between the center electrode 1 and the auxiliary electrode 4 provided on the end surface 3b of the metal fitting 3 instead of the main spark gap 6, and onto the surface of the leg. A spark plug described in Japanese Patent Publication No. Sho 58-10219 is known as a spark plug capable of burning out carbon deposits.

However, as shown in FIG. 2, this type of spark plug is provided with a sub-combustion chamber C in the cylinder head 11 having a nozzle B that communicates with the main combustion chamber A, and ignites the rich air-fuel mixture in the sub-combustion chamber. When used in an internal combustion engine (hereinafter simply referred to as an internal combustion engine) equipped with an auxiliary combustion chamber that burns a lean air-fuel mixture on the main combustion chamber side, the ignition position of the spark plug 10 greatly influences the heat resistance, ignition performance, and fouling resistance. However, as a result of various experiments, the inventor of the present invention has found that the spark plug used in this type of internal combustion engine has been completely widened. It is in the provision of plugs.

As a result of the experiment of the present invention, the following points were found depending on the firing position of the spark plug. In other words, (a) heat resistance is improved by setting the dimension 11 from the end surface of the metal fitting that forms the main spark gap to the tip surface of the center electrode in the order of -0.5 to +1.5; Even if it is poured, the heat resistance will deteriorate.

(b) Ignition performance is improved when both the main spark gap and the auxiliary spark gap, which flies when the insulation resistance decreases, are drawn in from the end face of the metal fitting. e9 Fouling resistance is worse if both the main spark gap and the auxiliary spark gap protrude from the end face of the metal fitting, and even worse if both are retracted to a large width, and is not proportional to the direction of ignitability. Therefore, it has been found that it is effective to set the dimension 12 from the end face of the metal fitting forming the auxiliary spark gag to the auxiliary electrode to -3,9 to -1,9HMK (4 (c)). However, the present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 3 is a sectional view of a main part of a 7-park plug according to an embodiment of the present invention, and it has basically the same configuration as the conventional spark plug shown in FIG. 1, except that a main spark gap 6 is formed. The only difference is the firing position of the tip surface 1a of the center electrode 1 and the firing position of the auxiliary electrode 4 that forms the auxiliary spark gap 7 provided within the inner surface 3a of the metal fitting 3.

That is, in the spark plug 10 of the present invention, the dimension 41 from the end surface 3b of the metal fitting 3 forming the main spark gear socket 6 to the tip surface 1a of the center pole 1 is -0.5 to +1.5 layer m and the auxiliary spark gap. 7. Excellent plug performance is achieved by placing the method 42 extending from the end surface 3b of the metal fitting 3 to the auxiliary electrode 4 into a specific position between -3, 9 and -1, 9. It is something. In addition, as a method of ignition position @ all alignment, it is possible to shorten the reach of the fitting, but in this case, since the end surface 3a of the fitting 3 is retracted from the wall surface of the auxiliary combustion chamber of the cylinder head 11, it is possible to shorten the reach of the fitting. This is not a preferable method because the exposed line B-1 of the female thread E becomes a hot spot and abnormal combustion occurs.

Next, 1. of the present invention. ．． The spark plug limited to 12'fr is installed so that the wall surface 4 of the sub-combustion chamber of the inner P engine and the end surface 3b of the metal fitting 8 are approximately on the same plane. We will explain in detail through experiments whether it contributes to widening. For experiments, commercially available 4-cycle/I/16Q
Evaluation will be made using a complete vehicle equipped with all Q cc auxiliary combustion chambers and its engine alone.

<1# Thermal> The spark plug used in the test has a mounting screw diameter M14, a reach 19, a dimension n2e 8.9ffW from the end surface 3b of the metal fitting 3 of the auxiliary electrode 4, and a center tip surface 1a of the electrode 1.
Dimension from to the end face of the insulator leg e3=l, 5 +#
Fix it to the shoulder, and from the end surface 3b of the metal fitting 3 to the tip surface 1aY of the center electrode 1 (l lk+ 2.5 (regular protrusion), +
1.5, +0.5 layer and -0,5-1,
5i@ and retracted samples were prepared, and the heat resistance test was conducted under the conditions of the above-mentioned engine at 5000 rqm x 4/4, changing the ignition advance angle and checking for the occurrence of pre-ignition. The results are shown in Figure 4↓ As shown, the heat resistance is +0
, 5H is the highest, and it is best to have a value within ±1.0 mm based on this value, which corresponds to the standard actual measurement of part number 1, and can sufficiently improve heat resistance without taking measures to shorten the leg length. Effects can be obtained.

Ignition performance> The test Nupark plugs include one with only the main spark gap, one with the auxiliary spark gap completely separated, and one with only the main spark gap (7) (!: Shite, gr 'jC+ 2 .5, +0.5, -1.5, -
3,5, -5.5 my and e2 for only the auxiliary spark gap -0,9, -2,9, -4,9, -
We prepared 6, 9, -8, and 9, respectively. The test was evaluated based on the idling speed or the number of errors caused by He during idling. As a result, as shown in FIG. 5, the rotational speed increases and the ignition performance improves as the metal is drawn in from the end face, both when the spark is caused by the main spark gap and when the spark is caused only by the auxiliary spark gap. It also matches the trend shown in Figure 6, which was evaluated based on the number of errors occurring during idling at the main ignition position.

<Fouling resistance> The spark plug used in this test was 1. =9.51
1M, 1z=2. 'JIH's invention plug h%1. =1
．． 5yttyx, l, = 1', 9yxxO Invention Grag B and as a comparison (l + = + 2.5 ho,
12 = 0.9 horse comparison plug c, (J ! =-'
Comparison graph D and l+=+ of 1.5 friends, 12 = 19 friends
Comparative products E with 2.5 h clear, 112 = o, and yx shoulder were prepared, and the test conditions were 110° room temperature and racing was repeated three times using a completed car. The insulation resistance was measured using a pattern combining 1 (X 1 minute) as one cycle, and this was repeated for 10 cycles in total.
=Q, )~+1.5πm, 12=-8,9~-1,9
The plugs A and B of the present invention, which are a combination within my range, have good stain resistance with little decrease in insulation resistance even after 10 cycles,
Similarly, the soft plug C has good stain resistance after 10 cycles, but in the range of 1 to 12, the heat resistance and ignitability are poor and it is not practical. Furthermore, the comparative plug D in which lI and 42 are retracted to a large width and the comparative plug E in which the protruding parts are extremely poor in stain resistance and are not practical.

As described above, in the spark plug of the present invention, the end face of the metal fitting is made approximately flush with the wall surface of the sub-combustion chamber, and the main spark gap and the auxiliary spark gap are all set within a specific range, and this n is set to the sub-combustion chamber. By using the spark plug in an inner cable engine, the heat resistance, ignitability, and fouling resistance of the plug can be improved, and the spark plug can easily be made into a wide range spark plug.

[Brief explanation of drawings]

Figure 1 is a front sectional view of the main parts of a conventional spark plug, Figure 2
The figure is a sectional view of main parts showing an internal combustion engine equipped with a sub-combustion chamber.
The figure is a cross-sectional view of the main part of the spark plug of the present invention arranged in the auxiliary combustion chamber, Figures 4 to 7 show the plug performance results, Figure 4 is the heat resistance graph, Figures 5 and 7 are the results of the plug performance. FIG. 6 is a graph of ignitability and FIG. 7 is a graph of stain resistance. 1... Center electrode 1a... Tip surface 2... Insulator 2a... Leg portion 8... Metal fitting 3b... End surface 4.
...Auxiliary electrode 6...Main spark gap 7...Auxiliary spark gear patent jaw person NGK Spark Plug Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Figure 6

Claims (1)

[Claims] (1) A spark plug for an internal combustion engine that is provided with a sub-combustion chamber having a nozzle that communicates with the main combustion chamber and ignites a rich air-fuel mixture in the sub-combustion chamber, wherein the end surface of the metal fitting of the spark plug is connected to the sub-combustion chamber. It is installed so that it is approximately flush with the room wall surface,
The dimension A'+ from the end surface of the metal fitting that forms the main spark gap of the spark plug to the tip surface of the center electrode is 0.5 to
+1.5ytrvt, and when the insulation resistance of the insulator legs decreases due to contamination, an auxiliary spark gap is formed between the inner surface of the metal fitting and the insulator legs. A spark plug characterized in that dimension 42 is set at a retracted position of -3,9 to -1,9.