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Daimler Chrysler Ag

Conti Temic Microelectronic Gmbh

Temic Telefunken Microelectronic Gmbh

Peter Bertelshofer

Peter Hohner

Hartung Wilstermann

Juergen Schenk

Roger Pohlmann

A method for monitoring a system controlled by a processor utilizes an integrated monitoring unit independent of the processor but integrated together with the processor in an integrated circuit, as well as a watchdog unit for preventing measures that influence the system. The watchdog unit is cyclically reset by the integrated monitoring unit.

Method for operating a processor-controlled system

A method and an apparatus for detecting knocking combustion in an internal combustion engine, by evaluating the ionic current signal sensed in the combustion chamber, is especially adapted to correct or compensate the ionic current signal for longterm variations arising therein, for example due to variations in the composition of the fuel as a result of contamination with metallic components or the like. Thereby, erroneous knock recognition is prevented. To achieve this, a frequency-filtered time-sampled knocking component integral of the ionic current signal generated in the present combustion cycle is multiplied by a correction value determined from at least one integral value of the ionic current signal generated during at least one prior combustion cycle. The correction value is preferably a time-weighted combination of plural difference values that are respectively determined by subtracting an average integrated value of the ionic current signal from the knocking component integral of the ionic current signal in plural prior combustion cycles, and that are stored in successive positions of a shift register. If the final corrected knocking component integral falls outside of an allowable range, a knock recognition signal is released.

Method and apparatus for detecting combustion knock from the ionic current in an internal combustion engine

A method of recognizing knocking combustion in an internal combustion engine involves sensing an ionic current in the combustion chamber and providing a corresponding ionic current signal, detecting the signal during a pertinent time window and band-pass filtering the signal for a pertinent frequency range characteristic of knocking phenomena, integrating the signal to provide a present integral value, and then comparing the present integral value to a lower knocking threshold and a higher knocking threshold. If the present integral value exceeds the lower knocking threshold but does not exceed the higher knocking threshold, the combustion is identified as a knocking combustion. If the present integral value exceeds the higher knocking threshold, the value is essentially disregarded as being implausible, and the combustion is identified either as non-knocking, or as the same combustion condition, i.e. either knocking or non-knocking, that had been determined in the previous combustion cycle. The knocking thresholds are updated to follow variations in the integral values that do not exceed the existing lower knocking threshold. Especially the higher knocking threshold is adjusted dependent on the present operating condition of the engine, as represented by a plurality of respectively differently weighted prior integral values. Whenever a knocking combustion is recognized, the higher knocking threshold is maintained at the previously determined value.

Method for detecting combustion knock from the ionic current in an

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Zirndorf, Germany

Peter Bertelshofer