Abstract: A rotational sensing assembly including a ferromagnetic sensor wheel rotationally fixed to a shaft having a tooth pattern including a missing tooth. An inductive sensor is mounted adjacent the periphery of the sensor wheel and in communication with a processor. The sensor produces a generally sinusoidal signal in response to the wheel rotation, with voltage zero crossings that are time stamped by the processor. The geometry of the sensor wheel around the missing tooth location is altered to equalize the induced voltage in the sensor for fixed time intervals in order to maintain proper timing of the zero crossings in the sensor signal.

Abstract: A method for more accurately sensing the rotational position of a shaft having a toothed sensor wheel with a missing tooth is disclosed. The method includes employing an inductive sensor to produce a signal in response to the passing of the teeth on the sensor wheel. The sensor signal is altered by the geometry of the wheel about a gap formed by the missing tooth in order to correct for residual stored energy in the sensor at this location, and thus correct the signal for the timing measured by a processor in communication with the sensor.

Abstract: An improved misfired detection system and method for high data rate engine control systems. A method of detecting misfires of individual cylinder events in an internal combustion engine is disclosed which includes the step of generating a high data rate velocity signal indicative of the torque behavior of the engine. The velocity signal is then filtered and separated into a plurality of non-interlaced homogeneous data sets wherein each of the data sets represents like portions of the internal combustion engine cycle. A median filter is then applied to each of the plurality of non-interlaced homogeneous data sets. In this manner, the data sets are normalized according to the applied recursive median filter and centered about a relative zero. This centering effect allows the signals to be recombined after filtering, thereby monitoring the nature of any deviations present in the signal. A threshold comparison of the resulting signal is then made to determine whether a misfire has occurred.