Siemens Aktiengesellschaft

Markus Amtmann

Stephan Bolz

J&uuml;rgen R&ouml;ssler

Roger Rouphael

Mark Elliott

Thomas Haug

Gerhard Fischer

A circuit configuration for generating a virtual ground includes a micro-controller, an analog circuit and a read-only memory. A pulse-width modulated signal, which is output by the micro-controller, is converted, by using the analog circuit, into the virtual ground as a common reference potential of an exhaust probe which operates according to the principle of the galvanic oxygen concentration cell with a solid electrolyte. The actual value of the virtual ground is read into the micro-controller through the use of an A/D converter and is compared with a predefined setpoint value. The potential value of the virtual ground is then controlled on the basis of the difference value. An exhaust probe configuration is also provided.

Circuit configuration for generating a virtual ground

A circuit configuration for controlling a pump current includes a microcontroller, an analog circuit and a read-only memory. A pulse-width modulated signal, which is output by the micro-controller, is converted, by using the analog circuit, into the pump current for a pump cell of an exhaust probe which operates according to the principle of the galvanic oxygen concentration cell with a solid electrolyte. A pump current actual value is determined from a voltage drop across a measuring resistor, and a pump current setpoint value is determined from a voltage difference between an actual value of a Nernst voltage in the corresponding measuring cell and a predefined setpoint value. An exhaust probe configuration is also provided.

Circuit configuration for controlling a pump current of an exhaust probe in a motor vehicle

A control circuit of an exhaust probe has a microcontroller and an analog circuitry. Measured values which are recorded in a test chamber under predefined test conditions are stored in characteristic maps in a programmable read-only memory. These values are then used as a reference for a subsequent recalibration of a probe system.

Method and device for calibrating a probe system

A method for monitoring the operation of sensors in an internal combustion engine includes providing reference values from output signals from a sensor. A sliding average (comparison value) is calculated from a relatively large number of reference values. The operation of the sensor is diagnosed as a function of the amplitude distribution of the reference values about the comparison value. If a malfunction is found, a fault message is transmitted to the driver and reversionary running of the internal combustion engine is started. An electric controller operating in accordance with the sensor is also provided.

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Wuppertal, Germany

Markus Amtmann