Abstract: A method of detecting a crank signal error that includes incrementing a crank tooth counter in response to detecting a crank signal, comparing the crank tooth counter to an expected value when a cam signal is detected, and indicating a crank signal error if the crank tooth counter is not substantially equal to the expected value. This method is advantageous because a cam interval used to determine when to start and stop counting crank tooth pulses is automatically adjusted for variations in engine speed, while the prior art time based methods must adjust the time interval for variations in engine speed.

Abstract: An engine control module and method configured to correct an engine crank sensor signal for errors in an apparent location of a tooth edge on a crank wheel is provided. A correction factor is determined based on a first formula if a comparison of adjacent pulse intervals to predetermined thresholds indicates that a tooth edge appears to be abnormally late, and determined based on a second formula if a comparison of adjacent pulse intervals to other predetermined thresholds indicates that a tooth edge appears to be abnormally The correction factor is set to a null value if the correction factor is not determined based on the first formula or the second formula; and operating an engine based on the correction factor.

Abstract: A method of detecting a crank signal error that includes incrementing a crank tooth counter in response to detecting a crank signal, comparing the crank tooth counter to an expected value when a cam signal is detected, and indicating a crank signal error if the crank tooth counter is not substantially equal to the expected value. This method is advantageous because a cam interval used to determine when to start and stop counting crank tooth pulses is automatically adjusted for variations in engine speed, while the prior art time based methods must adjust the time interval for variations in engine speed.

Abstract: A system for discrimination of spurious crankshaft encoder signals. A position encoder connected to an engine crankshaft sends a pulsed signal indicative of crankshaft rotational performance to an engine controller. The controller is programmed to trigger an interrupt service routine (ISR) on every falling or rising edge of each pulse. The ISR calculates and stores the period of each pulse and the period of the previous pulse and calculates the rotational speed and instantaneous acceleration or deceleration of the engine at all times. The controller is further programmed with realistic engine acceleration and deceleration limits and recognizes a next signal only within a time window corresponding to those limits and the engine speed. Signals arriving outside the calculated time window are considered spurious and are rejected. The system improves engine performance by preventing loss of synchronization between spark and fuel injection and piston and valve timing.

Abstract: A system for discrimination of spurious crankshaft encoder signals. A position encoder connected to an engine crankshaft sends a pulsed signal indicative of crankshaft rotational performance to an engine controller. The controller is programmed to trigger an interrupt service routine (ISR) on every falling or rising edge of each pulse. The ISR calculates and stores the period of each pulse and the period of the previous pulse and calculates the rotational speed and instantaneous acceleration or deceleration of the engine at all times. The controller is further programmed with realistic engine acceleration and deceleration limits and recognizes a next signal only within a time window corresponding to those limits and the engine speed. Signals arriving outside the calculated time window are considered spurious and are rejected. The system improves engine performance by preventing loss of synchronization between spark and fuel injection and piston and valve timing.