SPARK PLUG HOUSING INCLUDING CORROSION PROTECTION ON THE INNER SIDE AND SPARK PLUG AND MANUFACTURING METHOD

Abstract

A spark plug housing. The spark plug housing includes an inner side, an outer side, and a longitudinal axis, which extends from an end of the spark plug housing facing toward the combustion chamber up to an end of the spark plug housing facing away from the combustion chamber. The spark plug housing includes a circumferential shoulder on its inner side, which is designed so that a spark plug insulator rests thereon, and a corrosion protection layer on its inner side, which is formed on a section of the inner side of the spark plug housing, the section extending from the end of the spark plug housing facing toward the combustion chamber to at least over the shoulder and along the inner circumference of the spark plug housing.

Claims

1-10. (canceled)

11. A spark plug housing, comprising: an inner side, an outer side, and a longitudinal axis, which extends from an end of the spark plug housing facing toward a combustion chamber up to an end of the spark plug housing facing away from the combustion chamber, the spark plug housing including a circumferential shoulder on the inner side of the spark plug housing, the shoulder being configured so that a spark plug insulator rests on the shoulder; wherein the spark plug housing includes a corrosion protection layer on the inner side of the spark plug housing, the corrosion protection layer being formed on a section of the inner side of the spark plug housing, the section extending from the end of the spark plug housing facing toward the combustion chamber to at least over the shoulder and along the inner circumference of the spark plug housing.

12. The spark plug housing as recited in claim 11, wherein the corrosion protection layer is a layer applied by electroplating.

13. The spark plug housing as recited in claim 11, wherein the corrosion protection layer contains nickel and/or zinc.

14. The spark plug housing as recited in claim 11, wherein the corrosion protection layer also extends at least 1 mm in a direction of the end of the spark plug housing facing away from the combustion chamber starting from the shoulder.

15. The spark plug housing as recited in claim 11, wherein the corrosion protection layer has a thickness D of at least 2 μm on average, along a circumference of the section and/or along a longitudinal extension of the section.

16. The spark plug housing as recited in claim 11, wherein the corrosion protection layer has a uniform thickness, which has not more than 10% difference between a thickest and thinnest point.

17. The spark plug housing as recited in claim 11, wherein the spark plug housing only includes the corrosion protection layer on the inner side of the spark plug housing.

18. The spark plug housing as recited in claim 11, wherein the spark plug housing also includes further layers, the further layers including one or multiple intermediate layers and/or a sealing layer, in addition to the corrosion protection layer.

19. A spark plug, comprising: a spark plug housing, including an inner side, an outer side, and a longitudinal axis, which extends from an end of the spark plug housing facing toward a combustion chamber up to an end of the spark plug housing facing away from the combustion chamber, the spark plug housing including a circumferential shoulder on the inner side of the spark plug housing, the shoulder being configured so that a spark plug insulator rests on the shoulder, wherein the spark plug housing includes a corrosion protection layer on the inner side of the spark plug housing, the corrosion protection layer being formed on a section of the inner side of the spark plug housing, the section extending from the end of the spark plug housing facing toward the combustion chamber to at least over the shoulder and along the inner circumference of the spark plug housing; the spark plug insulator, the spark plug insulating being situated in the spark plug housing; a center electrode situated in the spark plug insulator; and a ground electrode situated at the end of the spark plug housing facing toward the combustion chamber, the ground electrode and the center electrode being configured to jointly form a spark gap.

20. A method for manufacturing a spark plug housing, the spark plug housing, including an inner side, an outer side, and a longitudinal axis, which extends from an end of the spark plug housing facing toward a combustion chamber up to an end of the spark plug housing facing away from the combustion chamber, the spark plug housing including a circumferential shoulder on the inner side of the spark plug housing, the shoulder being configured so that a spark plug insulator rests on the shoulder, wherein the spark plug housing includes a corrosion protection layer on the inner side of the spark plug housing, the corrosion protection layer being formed on a section of the inner side of the spark plug housing, the section extending from the end of the spark plug housing facing toward the combustion chamber to at least over the shoulder and along the inner circumference of the spark plug housing, the method comprising: electroplating at least one section on the inner side of the spark plug housing using the corrosion protection layer, by placing a coating electrode inside the spark plug housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows an example embodiment of a spark plug housing according to the present invention.

[0020] FIG. 2 shows a spark plug in accordance with an example embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0021] FIG. 1 shows a spark plug housing 2 according to an example embodiment of the present invention. Spark plug housing 2 includes an inner side 24, an outer side 23, an end 21 facing toward the combustion chamber, and an end 22 facing away from the combustion chamber. A shoulder 25, circumferential around inner side 24, is formed on inner side 24 of spark plug housing 2. This shoulder 25 is designed so that in a spark plug 1 including a spark plug insulator 3, this spark plug insulator 3 rests on shoulder 25.

[0022] A corrosion protection layer 50 is applied in one section 55 on the surface of spark plug housing inner side 24. Corrosion protection layer 50 extends from the end of the spark plug housing facing toward the combustion chamber up to at least 1 mm beyond shoulder 25 and along the inner circumference of spark plug housing inner side 24. In this example, corrosion protection layer 50 is formed on a section 55 having a length of at least 4 mm in parallel to the longitudinal axis of spark plug housing 2. Corrosion protection layer 50 includes a preferably uniform layer thickness D at an average of at least 2 μm along its circumference and along its longitudinal extension, the thickest and the thinnest point of the corrosion protection layer differing by not more than 10%.

[0023] Corrosion protection layer 50 has preferably been applied with the aid of an electroplating method, a coating electrode having been arranged inside spark plug housing 2 for the coating of spark plug housing inner side 24 with corrosion protection layer 50.

[0024] The spark plug housing is typically made of a carbon steel, such as C10 or C22.

[0025] FIG. 2 shows a spark plug 1 in a half-sectioned view. Spark plug 1 includes a spark plug housing 2, which has an inner side 24, an outer side 23, an end 21 facing toward the combustion chamber and an end 22 facing away from the combustion chamber. A spark plug insulator 3 is inserted into spark plug housing 2. Spark plug housing 2 and spark plug insulator 3 each have a bore along their longitudinal axis X. The longitudinal axis of spark plug housing 2, the longitudinal axis of spark plug insulator 3, and the longitudinal axis of spark plug 1 coincide. A center electrode 4 is inserted into spark plug insulator 3. Furthermore, a connector pin 8 with a terminal nut, via which spark plug 1 is electrically contactable with a voltage source (not shown here), extends in spark plug insulator 3. Connector pin 8 with the terminal nut form the end of spark plug 1 facing away from the combustion chamber.

[0026] A resistor element is located in insulator 3 between center electrode 4 and connector pin 8. The resistor element connects center electrode 4 electrically conductively to connector pin 8.

[0027] Insulator 3 rests with a shoulder on a circumferential shoulder 25 formed on inner side 24 of spark plug housing 2. A sealing core, which is plastically deformed when spark plug insulator 3 is clamped in spark plug housing 2 and thus seals off the air gap, is situated between the insulator shoulder and shoulder 25 to seal off the air gap between spark plug housing inner side 24 and insulator 3.

[0028] A ground electrode 5 is situated electrically conductively at spark plug housing 2 on its combustion chamber-side end 21. Ground electrode 5 and center electrode 4 are situated in relation to one another in that a spark gap forms between them, in which the ignition spark is generated.