System and method for updating a baseline output of a gas sensor

• US 9,470,654 B2
• Filed: 05/21/2009
• Issued: 10/18/2016
• Est. Priority Date: 12/07/2005
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Kubinski, David, Soltis, Richard, Visser, Jacobus H., Ding, Yi, Parsons, Michael Howard
• Primary Examiner(s): Van, Luan
• Assistant Examiner(s): ROSENWALD, STEVEN ERIC
• Application Number:
  US12/469,874
• Publication Number:
  US 20090223835A1
• Time in Patent Office: 2,707 Days
• Field of Search: 204/406, 204421-427, 205/780.5, 205/781, 205782-786, 73/233.1, 73/233.2, 73 3503- 3507, 7311401-11469
• US Class Current: 1/1
• CPC Class Codes: G01N 27/417 using cells , i.e. more than one cell and probes with solid electrolytes

Abstract

A method of operating a gas sensor is disclosed, wherein the sensor includes a pumping electrode configuration and a measuring electrode configuration, and wherein the method includes operating the sensor in a first mode in which a first, lower pumping potential sufficient to electrochemically remove an interfering compound from the sensor without electrochemically removing the analyte from the sensor is applied across the pumping electrode configuration and a measuring potential sufficient to electrochemically remove the analyte from the sensor is applied across the measuring electrode configuration; and operating the sensor in a second mode in which a second, higher pumping potential sufficient to electrochemically remove the analyte from the sensor is applied to the pumping electrode configuration.

Claims

1. A method of operating a NO_x sensor, wherein the sensor includes a pumping electrode configuration and a measuring electrode configuration, the method comprising:

operating in a first update operating mode responsive to determining that the NO_x sensor is operating under first conditions that cause an absence of NO_x in exhaust gas, the first update operating mode including removing NO_x and at least a portion of O₂ from the sensor;

determining that the NO_x sensor is operating under second conditions that cause a change in residual O₂ reaching the measuring electrode configuration; and

responsive to the determining, operating in a second, alternate update operating mode, the second, alternate update operating mode including,

applying a first measuring voltage across the measuring electrode configuration sufficient to electrochemically remove O₂ from the sensor without electrochemically removing NO_x from the sensor; and

applying a second measuring voltage across the measuring electrode configuration sufficient to electrochemically remove NO_x from the sensor.

2. The method of claim 1, further comprising receiving a first output signal from the NO_x sensor while applying the first measuring voltage, and receiving a second output signal from the NO_x sensor while applying the second measuring voltage.

3. The method of claim 2, further comprising determining a difference between the first and the second output signals and storing said difference.

4. The method of claim 1, further comprising performing said method at least once during an engine drive cycle.

5. The method of claim 2, further comprising adjusting an operating condition of an engine based on at least one of the first and the second output signals.

6. The method of claim 5, wherein the operating condition of the engine includes at least one of an amount of air supplied to the engine, an amount of fuel supplied to the engine, a combustion timing, a valve timing, a turbocharging condition, a supercharging condition, a throttle condition, and a NO_x trap condition.

7. A method of operating a NO_x sensor, wherein the sensor includes a pumping electrode configuration and a measuring electrode configuration, the method comprising:

applying a first pumping voltage across the pumping electrode configuration sufficient to electrochemically remove NO_x and O₂ from the sensor;

applying a first measuring voltage across the measuring electrode configuration sufficient to electrochemically remove NO_x from the sensor;

responsive to detecting no change in residual O₂ reaching the measuring electrode configuration, operating in a first update operating mode, the first operating mode including removing NO_x and at least a portion of O₂ from the sensor; and

responsive to detecting a change in residual O₂ reaching the measuring electrode configuration, operating in a second, alternate update operating mode, the second, alternate update operating mode including,

applying a second measuring voltage across the measuring electrode configuration sufficient to electrochemically remove O₂ from the sensor without electrochemically removing NO_x from the sensor; and

applying a third measuring voltage across the measuring electrode configuration sufficient to electrochemically remove NO_x from the sensor.