Robert Boschgmbh

Manfred Hundhausen

Erich Schneider

Klaus Hirschmann

Thomas Wenzler

Achim Guenther

Bernhard Vogt

A method for detecting combustion misfires of an internal combustion engine and a device for carrying out the method, in which an evaluation of a lambda signal made available by at least one broadband lambda sensor is provided. The lambda signal is compared to a lambda signal threshold value. A warning signal is made available in response to the exceeding of a threshold in the direction of lean combustion. The procedure especially makes possible the detection of continual misfires which occur, for example, in response to an error in the air supply to the internal combustion engine and/or because of a lack of fuel. The procedure makes possible the detection of dangerous situations for at least one exhaust gas treatment device that is present, which may be removed by introducing protective measures, error warnings and error memory entries.

Method for detecting misfires of an internal combustion engine and device for carrying out the method

An internal combustion engine () is operated by a method wherein the fuel is supplied via a magnetic valve () having a coil (). The injected fuel quantity is influenced by the duration of the drive of the magnetic valve (). In the method, the temperature (evtmod) of a region () of the magnetic valve () is determined and the drive duration is corrected in dependence upon temperature. In order to make the correction still more precise, a temperature (evtmod) of the magnetic valve () is determined from at least one usually measured temperature (tans, tmot) and the drive duration (ti_tvu_w) is so corrected (tvsp_w) that the temperature dependency of the characteristics of the magnetic coil () of the magnetic valve () is considered. Furthermore, a model is suggested in which (starting from an operating temperature) the temperature trace is simulated after shut-off of the engine and/or for the restart of the engine by means of two factors for the warmup and cool down.

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Bietigheim-Bissingen, Germany

Manfred Hundhausen