Siemens Aktiengesellschaft

Christian Zimmer

Ralf Böhnig

Guy-Michel Cloarec

When detecting the combustion noise on a combustion engine () by using a knock sensor (), the problem arises in that prior art methods cannot determine with sufficient accuracy how much fuel reaches the cylinder () of the combustion engine () during a specified injection pulse. For different reasons, e.g. for minimizing the fuel consumption or for optimizing exhaust emissions, a multiple injection with, in part, the smallest quantities of fuel is commonly used in today's combustion engines () that require a precise fuel metering. To this end, the measuring window (M) for detecting the combustion noises of an individual injection pulse with regard to its starting and/or ending position is variably formed according to operating parameters so that only the combustion noises taken into consideration are detected that serve as a measure for the injected quantity of fuel.

Method and device for analyzing the combustion noise in a cylinder of an internal combustion engine

In the case of direct injection internal combustion engines, the problem occurs that especially the injection of a minimum amount of fuel depends in particular on different operating parameters such as the speed, the start of the injection or the rail pressure. Therefore, a method or a device is suggested in which a control unit () subdivides the complete range of values of at least one operating parameter into discrete sections. Subsequently, for each section, at least one operating point is specified for which a corresponding correction value depending on the operating parameter is determined and obtained. The correction value is then stored together with its corresponding operating point. This has the advantage that the correction value can be determined more accurately because interpolation can for example also be performed between two operating points.

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Wuppertal, Germany

Christian Zimmer