Spark plug

A spark plug and insulator technology, applied in the field of spark plugs, can solve the problem of the overheated front end of the spark plug becoming a spark source, and achieve the effect of promoting fouling resistance

Active Publication Date: 2012-07-11
NGK SPARK PLUG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, when the temperature of the tip of the spark plug is excessively heated above a predetermined temperature (for example, 1100° C.), there is a fear that the overheated tip of the spark plug becomes a spark source

Method used

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Examples

Experimental program
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Embodiment Construction

[0054] Hereinafter, embodiments will be described with reference to the drawings. figure 1 It is a partially cutaway front view showing the structure of the spark plug 1 . exist figure 1 In the description, the direction of the axis line CL1 of the spark plug 1 will be described as the vertical direction in the figure, the lower side will be the front end side of the spark plug 1 , and the upper side will be the rear end side.

[0055] The spark plug 1 is constructed of a cylindrical insulator 2 as an insulator and a cylindrical metal case 3 holding the insulator 2 .

[0056] The insulator 2 is formed of calcined alumina or the like known in the art, and includes: a rear end side main body portion 10 formed on the rear end side in the profile portion; a large diameter portion 11 on the rear end side The main body part 10 is formed to protrude outward in the radial direction at a position near the front end side; the middle main body part 12 is formed with a diameter smalle...

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PUM

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Abstract

Provided is a spark plug with a center electrode that has the diameter thereof made thinner, wherein stain-resistant and heat-resistant characteristics are improved. The spark plug (1) is provided with a center electrode (5), an insulator (2), and a main metal-part (3), and the insulator (2) is provided with a long-leg section (13), a tapered section (14), and a mid-body section (12). The maximumouter-diameter of a portion of the center electrode (5) to be arranged within the long-leg section (13) is to be 3.0 mm or shorter. A step section (21) and a front-tip-side inner circumference section (51) are formed on the inner circumference of the main metal part (3), and the tapered section (14) is latched together to the step section (21). An inequality 0.12<= A / B<= 0.24 is satisfied, when the volume of a portion of the insulator (2) existing along the axis (CL1) direction, from the tip of the insulator (2) to a place 2 mm from the rear-end side, is assumed to be A (mm3), and the volume of a portion of the tapered section (14) located at the front tip side of the rear end of the portion to be latched together with the step section (21), and which portion has the difference in the diameters of the front-tip side inner circumference section (51) and the outer circumference part of itself to be 1.5 mm or less, is assumed to be B (mm3).

Description

technical field [0001] The present invention relates to spark plugs used in internal combustion engines and the like. Background technique [0002] The spark plug is installed to a combustion device in an internal combustion engine or the like and is used to ignite an air / fuel mixture in a combustion chamber. Generally, a spark plug includes an insulator with an axial hole, a center electrode inserted into the axial hole, a metal shell disposed on the outer periphery of the insulator, and a ground electrode disposed on the front end of the metal shell to form a spark discharge gap with the center electrode. In addition, when the metal shell and the insulator are assembled, generally, the stepped portion arranged on the inner peripheral surface of the metal shell and the tapered portion arranged on the outer peripheral surface of the insulator are joined by the sheet metal seal. [0003] However, carbon is produced due to incomplete combustion of the air / fuel mixture in the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01T13/20F02P13/00H01T13/14H01T13/16
CPCF02P13/00H01T13/39H01T13/14H01T13/20H01T13/16
Inventor 伴谦治铃木彰
Owner NGK SPARK PLUG CO LTD
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