Abstract: In a motor vehicle having an engine with an exhaust catalyst and an oxygen sensor upstream of the catalyst and an oxygen sensor downstream of the catalyst, a method for detecting whether the catalyst has aged. Over a test block period of time, the method periodically obtains upstream data points from an oxygen sensor located upstream of the catalyst and from and oxygen sensor located downstream of the catalyst. Absolute differences are calculated between consecutive pairs of the upstream data points and the downstream data points. A ratio between the sums of absolute differences is then calculated, and the ratio is used to determine whether the catalyst has aged.

Abstract: A non-intrusive method and arrangement for detecting the aging of an oxygen sensor, without increasing tailpipe emissions, is provided. The method detects an aging oxygen sensor, located between a motor vehicle engine and a catalytic converter, by sampling a series of oxygen level signals taken over a calibratable time block only when at least one engine operating condition satisfies a predetermined criterion whereunder the method will not intrude upon the engine controller's ability to minimize undesirable exhaust emissions. After a series of signal processing, the samplings are then compared to calibratable thresholds in order to determine the aging degree of the oxygen sensor.

Abstract: A non-intrusive method and arrangement for detecting the aging of an oxygen sensor, without increasing tailpipe emissions, is provided. The method detects an aging oxygen sensor, located between a motor vehicle engine and a catalytic converter, by sampling a series of oxygen level signals taken over a calibratable time block only when at least one engine operating condition. satisfies a predetermined criterion whereunder the method will not intrude upon the engine controller's ability to minimize undesirable exhaust emissions. After a series of signal processing, the samplings are then compared to calibratable thresholds in order to determine the aging degree of the oxygen sensor.

Abstract: In a motor vehicle having an engine with an exhaust catalyst and an oxygen sensor upstream of the catalyst and an oxygen sensor downstream of the catalyst, a method for detecting whether the catalyst has aged. Over a test block period of time, the method periodically obtains upstream data points from an oxygen sensor located upstream of the catalyst and from and oxygen sensor located downstream of the catalyst. Absolute differences are calculated between consecutive pairs of the upstream data points and the downstream data points. A ratio between the sums of absolute differences is then calculated, and the ratio is used to determine whether the catalyst has aged.

Abstract: A system and method for use in a motor vehicles is disclosed for calculating a fuel multiplier during transient engine operation. The fuel multiplier modifies the amount of fuel released from a fuel actuator into an engine. The fuel control system uses neural network logic to establish the fuel multiplier. The neural network logic involves taking inputs from engine sensors, processing the inputs through an input layer, a hidden layer and an output layer resulting in a fuel multiplier.

Abstract: A system and method for use in a motor vehicles is disclosed for calculating a fuel multiplier during transient engine operation. The fuel multiplier modifies the amount of fuel released from a fuel actuator into an engine. The fuel control system uses neural network logic to establish the fuel multiplier. The neural network logic involves taking inputs from engine sensors, processing the inputs through an input layer, a hidden layer and an output layer resulting in a fuel multiplier.

Abstract: A method is provided for monitoring catalyst efficiency in a catalytic converter of a motor vehicle, comprising the steps of: (a) detecting an oxygen level of an exhaust gas from the vehicle's engine by using an oxygen sensor positioned at the outlet of the catalytic converter; (b) terminating fuel flow to the vehicle's engine; (c) detecting a change in the oxygen level in response to terminating fuel flow; (d) determining a time period from termination of fuel flow to detection of the change in oxygen level; and then (e) compensating this time period with respect to an exhaust flowrate, such that the compensated time period is indicative of catalyst efficiency of the catalytic converter. More specifically, the exhaust flowrate is determined from a manifold absolute pressure and an engine rotational speed of the engine. To achieve reliable and consistent results, catalyst monitoring of the present invention is only enabled under preferred vehicle operating conditions.

Abstract: A catalyst monitoring system is provided for monitoring catalyst efficiency in a catalytic converter of a motor vehicle. The catalyst monitoring system includes a catalyst monitor receiving electrical signals indicative of oxygen in the exhaust gas from a first oxygen sensor positioned between the vehicle's engine and the catalytic converter and a second oxygen sensor positioned downstream from the catalytic converter. Each of these input signals are filtered in the catalyst monitor such that a particular range of frequencies that encapsulate information regarding catalyst efficiency are passed. The filtered signals are then used to establish an amplitude ratio between the downstream oxygen signal and the upstream oxygen signal, such that the algorithm output linearly correlates to catalyst efficiency of the catalytic converter. Digital signal filtering is preferably implemented using a finite impulse response bandpass filter, a full-wave rectifier, a low pass filter, a sampler and a signal normalizer.

Abstract: A method of misfire detection for an internal combustion engine in a motor vehicle includes the step of sampling a misfire indicator and filtering the misfire indicator to provide a filtered misfire indicator. The method also includes the step of selecting one misfire indicator point from the filtered misfire indicator. The method further includes the steps of comparing the one misfire indicator point to a misfire threshold to detect a misfire event and identifying a misfire if a misfire event is detected.

Abstract: An apparatus and method are provided for detecting cylinder misfires in an internal combustion engine of a motor vehicle by digitally filtering out noise-related signals to improve the signal to noise ratio. Crankshaft rotation is sensed and crankshaft velocities are measured for each cylinder. Changes in angular velocity are determined and correspond to each of a plurality of cylinder firing events. A window of consecutive changes in angular velocity are used with a digital filter. The digital filter contains filter coefficients which are determined from a frequency analysis for a given engine by distinguishing between actual misfire events and noise related event frequencies. From the analysis a cut off frequency between actual misfires and noise is determined which is then used to determine the filter coefficients. The digital filter generates a filter output for the current cylinder firing event and the filter output is preferably multiplied by a gain to provide a compensated filter output.