US 11,876,351 B2
Thermally optimized prechamber spark plug
Bernd Mueller, Korntal-Muenchingen (DE); Matthias Blankmeister, Heiligenhaus (DE); Stephan Kaske, Sternenfels Diefenbach (DE); Thomas Steidten, Ludwigsburg (DE); and Ugur Yilmaz, Markgroeningen (DE)
Assigned to ROBERT BOSCH GMBH, Stuttgart (DE)
Appl. No. 18/248,587
Filed by Robert Bosch GmbH, Stuttgart (DE)
PCT Filed Dec. 1, 2021, PCT No. PCT/EP2021/083758
§ 371(c)(1), (2) Date Apr. 11, 2023,
PCT Pub. No. WO2022/128473, PCT Pub. Date Jun. 23, 2022.
Claims priority of application No. 10 2020 215 946.7 (DE), filed on Dec. 15, 2020.
Prior Publication US 2023/0378723 A1, Nov. 23, 2023
Int. Cl. H01T 13/32 (2006.01); H01T 13/36 (2006.01); H01T 13/54 (2006.01)
CPC H01T 13/36 (2013.01) [H01T 13/54 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A prechamber spark plug, comprising:
a center electrode;
a ground electrode;
a housing having an external thread;
a cap disposed on the housing and together with the housing defines a prechamber; and
an insulator which electrically insulates the center electrode from the housing;
wherein the external thread of the housing has a thread length in an axial direction of the prechamber spark plug;
wherein the housing is fastened to the insulator at a first fixing region and a second fixing region such that a first clamping force at the first fixing region acts from the housing on the insulator, and a second clamping force at the second fixing region acts from the housing on the insulator, wherein the first and second clamping forces are directed in opposite directions to one another in the axial direction;
wherein a distance between the first fixing region and the second fixing region in the axial direction defines a clamping length; and
wherein a ratio between the thread length and the clamping length is in a range of 0.7 to 1.3.