Patent ID: 7350405

Claim:
A noise-resistant method of monitoring crankshaft position of an internal combustion engine, said method comprising providing a rotating member operationally coupled to said crankshaft, wherein said rotating member comprises a plurality of spaced elements and at least one reference element provided with a different spatial characteristic thereon; providing one or more crankshaft positioning sensors proximate to said rotating member so as to allow generation of at least one corresponding crank signal streams responsive to rotation of said rotating member; monitoring for crank signal generation during a predetermined inspection window, wherein, during undisturbed crank signal generation, a predefined number of crank signals occur in said predetermined inspection window; generating a virtual crank signal stream derived from crank signals of at least one crank signal stream, (i) said virtual crank signal stream persisting despite an addition of one or more false crank signals or deletion of one or more true crank signals that occur during said predefined inspection window; (ii) said virtual crank signal stream comprising a phase relative to said crankshaft that is monitored and maintained to correlate to a predicted location of said crankshaft despite noise on a crank signal stream; (iii) said virtual crank signal stream being monitored for integrity of the reference element of said virtual crank signal stream, wherein if the integrity of said reference element is violated, protection of said engine is initiated; whereby said virtual crank signal stream is useful to achieve noise-resistant monitoring of crankshaft position.