Internal combustion engine with spark plug subject to high temperature operating conditions

Claim 1

IN AN INTERNAL COMBUSTION ENGINE SUBJECT TO HIGH OPERATING TEMPERATURES, THE COMBINATION OF (A) A METAL HOUSING, A PORTION OF WHICH FORMS A WALL OF THE ENGINE COMBUSTION CHAMBER, (B) SAID CHAMBER WALL HAVING A SPARK PLUG PILOT THAT IS CYLINDRICAL THROUGHOUT A PORTION OF ITS LENGTH AND RESTRICTED IN CROSS-SECTIONAL AREA AT ITS END ADJACENT TO THE CHAMBER TO FORM A CONICAL SEAT CONCENTRIC WITH THE PILOT, THE CONICAL SEAT BEING SPACED FROM SAID COMBUSTION CHAMBER, (C) A SPARK PLUG FREELY MOUNTED FOR LIMITED LATERAL ADJUSTMENT WITHIN THE PILOT, SAID PLUG INCLUDING A METAL CYLINDER TERMINATING IN A FRUSTRO-CONICAL PORTION AT THE FIRING END OF THE PLUG AND CORRESPONDING IN CONE ANGLE TO SAID CONICAL SEAT FOR MAKING A METAL-TO-METAL SEALING FIT THEREWITH, (D) AND MEANS INTERCONNECTING SAID SPARK PLUG AND HOUSING FOR HOLDING SAID PLUG IN THE PILOT AND FORCING IT INTO FIRM SEALING ENGAGEMENT WITH SAID CONICAL PILOT SEAT, AND FOR CAUSING VARIATION OF THE PLUG SEATING FORCE IN ACCORDANCE WITH ADJUSTMENT OF SAID MEANS, SAID HOLDING MEANS ALLOWING LIMITED TRANSVERSE MOVEMENT OF THE PLUG WITHIN THE PILOT FOR CENTERING ON THE CONICAL SEAT AND THEREBY CORRECTING SLIGHT MISALINEMENT OF THE PLUG AND PILOT AXES, (E) THE COMMON SLOPE OF SAID PILOT SEAT AND CORRESPONDING FRUSTRO-CONICAL PORTION FORMING A SHARP ACUTE ANGLE WITH RESPECT TO THE LONGITUDINAL AXIS OF THE PILOT SEAT AND HAVING AN OPTIMUM VALUE WHEREBY THE LONGITUDINAL FORCE COMPONENT TENDING TO CAUSE BULGING OF THE CHAMBER WALL IN CLOSE PROXIMITY TO THE COMBUSTION CHAMBER IS MATERIALLY LESS THAN THE REQUIRED SEALING FORCE NORMAL TO THE PILOT SEAT, AND A COMPARATIVELY LARGE CONE SEAT SURFACE AREA IS PROVIDED FOR EFFECTIVE PRESSURE SEALING AND HIGH RATE OF HEAT TRANSFER FROM THE PLUG-TIP REGION OF THE METAL CYLINDER TO THE HOUSING WALL.