Patent ID: 6019086
Filing Date: 2000-02-01
Classification: F02D,F02P,G01D,G01M,G01P

Abstract:
An engine control system for an internal combustion engine comprising:an engine control module (ECM) having a microprocessor including means for implementing engine control routines operable to control the operation of a vehicle engine, some of said routines utilizing engine speed and timing information;a timing wheel arranged to be driven by the vehicle engine, said timing wheel including a plurality of spaced ferromagnetic elements, each having a width;a sensor apparatus mounted relative to said timing wheel to sense the passage of said ferromagnetic elements, said sensor apparatus including a primary magnetic sensor and an independent secondary magnetic sensor spaced apart a distance less than said width of said spaced ferromagnetic elements, each of said sensors producing corresponding independent output signals indicative of the passage of said ferromagnetic elements in the proximity of each sensor;a connector engaged between said sensor apparatus and said ECM for providing said output signals from said primary and secondary sensors to said ECM;wherein said ECM includes;means for reading the primary output signal and for determining engine speed and timing information from the primary output signal from said primary sensor;means for determining a phase difference value between said primary output signal from said primary sensor and the secondary output signal from said secondary sensor;means for reading said secondary output signal, applying said phase difference value to modify said secondary output signal and determining engine speed and timing information from said modified secondary output signal upon a failure of said primary sensor; andmeans for providing the engine speed and timing information to the engine control routines.