摘要 |
To protect the light guide element of a combustion sensor, for example combined with a spark plug, and extending through a bore in the center electrode thereof against high temperatures and attach due to environmental conditions occurring within the combustion chamber, a protective element of a high temperature resistant, light transmitting ceramic, preferably alpha-crystalline aluminum oxide is located at the combustion end portion, for example in form of a disc 14, held in position by a turned-over flange of the end portion of the center electrode 13 of a spark plug-sensor combination.
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