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US 7,461,536 B2Granted
Circuit arrangement for operating a gas sensor
AssigneeRobert Bosch GmbH
InventorsEberhard Schnaibel, Erich Junginger, Andreas Koring, Ruediger Deibert, Harry Braun, Lothar Diehl
Life of this patent
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Abstract
A circuit configuration for operating a gas sensor is described, including a reference gas space in which an electrode is situated which is supplied with a reference gas pump current to maintain the concentration of the reference gas. A diagnostic system determines a concentration change of the reference gas via a change in the reference pump current and a time-based evaluation of the sensor signal of the gas sensor.
Claims12
A circuit configuration for operating a gas sensor, comprising:
- a structure including a reference gas space;
- a reference electrode situated in the reference gas space;
- a current source for supplying a reference pump current to the reference electrode;
- and
- a diagnostic system including a timer, wherein the diagnostic system:
- delivers a current selection signal to the current source for setting the reference pump current during a diagnostic operation of the gas sensor;
- delivers a switch signal to the timer for starting the timer;
- evaluates a sensor signal of the gas sensor during diagnostic operation based on time;
- and
- evaluates a rate of change of the sensor signal.
7 more elements
A circuit configuration for operating a gas sensor, comprising:
- a structure including a reference gas space;
- a reference electrode situated in the reference gas space;
- a current source for supplying a reference pump current to the reference electrode;
- and
- a diagnostic system including a timer, wherein:
- the diagnostic system delivers a current selection signal to the current source for setting the reference pump current during a diagnostic operation of the gas sensor;
- the diagnostic system delivers a switch signal to the timer for starting the timer;
- the diagnostic system evaluates a sensor signal of the gas sensor during diagnostic operation based on time;
- the diagnostic system includes a comparator that compares the sensor signal with a threshold value to produce a comparison result and supplies a diagnostic signal as a function of the comparison result;
- the diagnostic signal stops the timer;
- the timer supplies an end signal that represents a time elapsed, and
- the current selection signal is set as a function of the end signal for operating the gas sensor outside of the diagnostic operation.
9 more elements
Dependencies are inferred from the claim text.