IC engine cylinder head seal with knock or misfire detector - senses change in polarisation of light due to variation of pressure on birefringent optical waveguide around or across opening into combustion chamber

摘要

Around each combustion-chamber opening (2) of a straight-four cylinder head, is wound an optical waveguide (3), with both ends (4,5) protruding through the gasket (1). A polariser (6) and an analyser (7) at the respective ends detect variations of pressure on the light-guide due to irregularities in the combustion, whether caused by knock or misfiring. The changes in polarisation detected by the analyser are transmitted to processing devices and controls for the regulation of the combustion process. ADVANTAGE - Pressure-measuring device for detecting irregular combustion is simple, compact and immune from interference.