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 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: Measured engine inlet air temperature and flow parameters are communicated to an engine controller with a single waveform. A variable frequency digital input signal representative of inlet air flow is combined with a variable amplitude analog signal representative of inlet air temperature, and supplied as a single input signal to the engine controller. The controller includes a buffer circuit that re-creates the variable frequency digital signal from the input waveform for application to an input capture circuit that measures the flow-related frequency, and an analog-to-digital converter that is coordinated with the input capture circuit for sampling the temperature-related amplitude.

Abstract: A default engine control method for an internal combustion engine recovers from the loss of a high-resolution engine position signal by calculating a high resolution pulse period based on a recognized pattern of a low resolution engine position signal. Interrupts for signaling the execution of cycle-related control algorithms are scheduled in time based on the calculated pulse period, and pulse period errors due to changing engine speed are periodically corrected based on the timing of subsequent transitions in the low resolution position signal relative to the scheduled interrupts.

Abstract: A controller for airbags and seat belt pretensioners stores a digital flag for each restraint to enable or disable the corresponding deployment loop. A diagnostic tester is coupled by a communications link to the controller to selectively set the flags as desired. The controller stores a seed and a key and the tester is provided with an algorithm which can calculate the key from the seed. The tester requests the seed, which is supplied, and then calculates the key and sends the key to the controller along with a request to set the status of the deployment loops. If the transmitted key matches the stored key, the controller will comply with the request and set the flags accordingly.

Abstract: A SIR system has frontal air bags and side air bags both controlled by the same microprocessor. To guard against spurious deployment of side air bags with minimal software burden, a lateral accelerometer and an arming circuit detect side crash activity and apply an arming signal to a pulse accumulator circuit in the microprocessor which monitors the accumulator state to detect arming, thereby inhibiting deployment when the arming signal is absent. The arming circuit receives the accelerometer signal, removes the dc component which is subject to drift, adds a fixed offset voltage and compares the resultant signal to threshold values to produce an arming signal when a threshold is breached.