Siemens Aktiengesellschaft

J&uuml;rgen R&ouml;ssler

Hong Zhang

Stephan Bolz

Markus Amtmann

Corinna Pfleger

The NO concentration in a gas is determined with a thick-film measuring sensor which has two measuring cells. The raw measured value of the measuring sensor is corrected by a multiplicative correction value and an additive correction value, which are both taken from a characteristic map. The characteristic map depends on the oxygen-ion pumping current in the second measuring cell, the measured gas temperature, and the measuring sensor temperature.

Method for determining a nitrogen oxide concentration

A method is provided for checking the dynamic behavior of a measuring sensor which detects a substance concentration in the exhaust tract of an internal combustion engine operating with excess air, downstream of an NOx storage catalytic converter. A signal from the measuring sensor is monitored during a regeneration phase. When a predetermined signal profile is absent, a faulty dynamic behavior is diagnosed.

Method for checking the dynamic behavior of a measuring sensor in the exhaust tract of an internal combustion engine

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 NO concentration of a gas is measured with a NO measuring sensor which has two measuring cells. An oxygen concentration is respectively corrected by a oxygen-ion pumping current. A controller is used for correcting a transitional resistance through which the first oxygen-ion pumping current flows at the first measuring cell, the controller correcting at least partially a correction value for the transitional resistance by using the second oxygen-ion pumping current at the second measuring cell.

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.

Growing community of inventors

Münnerstadt, Germany

Jürgen Rössler

Growing community of inventors

Münnerstadt, Germany

J&uuml;rgen R&ouml;ssler

Jürgen Rössler