Abstract: A system and method of discriminating faults in an error signal, such as that from a control input sensor, comprises a system for and method of determining allowable limits of an error signal versus time, passing the error signal through a low-pass filter, comparing output of the low-pass filter with a threshold and outputting a fault condition when the output of the low-pass filter exceeds the threshold. The time constant or constants of the low-pass filter and the threshold are selected so that a fault condition is detected when the error signal approaches the allowable limits before exceeding them.

Abstract: A diagnostic system for electric motors, such as those used in automotive applications. The system comprises a controller for supplying a desired command current to said electric motor, a sensor for measuring the rotational speed of the motor, a sensor for measuring the actual current supplied to the motor by the controller, a diagnostic control unit adapted to receive the measured rotational speed, measured supplied voltage, and a command current level value as inputs. The diagnostic control unit further comprises circuitry to calculate an estimated actual current drawn by the motor and to signal an error condition if the estimated actual current is not within a calculated valid range.

Abstract: A pulsed measurement technique for calorimetric sensors provides a short current pulse through catalyzed and inert sensor elements to minimize self heating while providing for sensor resistance measurement, so that a determination of the level of catalytic activity at the surface of the catalyzed element may be made for sensing the concentration of combustible elements of automotive internal combustion engine exhaust gas. Exhaust gas temperature measurement is provided by monitoring the inert element resistance. Exhaust gas flow rate measurement is provided by heating the inert element for a short heating period, and then removing the heat source while monitoring the time rate of return to the known initial inert element temperature.