Engine shaft revolution rate measurement and sector detection - using common disc reference and sector separating marker sensing

摘要

The transducer, pref. inductive, determines the revolution rate and/or a marked angular position of a multiple cylinder combustion engine shaft. A disc (5) rotating with the shaft is divided into sectors (1-12) separated by sharply defined markers (21-32). The disc periphery is designed to facilitate simple detection of individual sectors of a reference marker (33) in one sector using a common sensing arrangement for economy. The angular separation of the reference marker (33) and its preceding marker (32) is more than twice or less than half the angular separation of the reference marker and the subsequent marker (21). The angular marker width is between 2 degrees and 5 degrees, pref. 3 degrees. The separation between markers is about 30 degrees. 5 degrees offsets may be used between neighbouring markings.