Gas concentration measuring apparatus compensating for error component of output signal
First Claim
1. A gas concentration measuring apparatus comprising:
- a gas concentration sensor including a gas chamber, a first cell responsive to application of a voltage to pump oxygen molecules selectively out of and into gasses admitted into the gas chamber to produce an electric current indicative of a concentration of the oxygen molecules, a second cell working to determine a concentration of a specified oxygen containing gas component contained in the gasses having passed through the first cell, and a monitor cell working to monitor a concentration of residual oxygen molecules within the gas chamber and provide an output indicative thereof;
an applying voltage determining circuit looking up a predetermined voltage-to-current relation to determine a target voltage to be applied to said first cell as a function of the electric current produced by said first cell so as to preclude said first cell from decomposing the specified oxygen containing gas component; and
an applying voltage controlling circuit working to apply the target voltage determined by said applying voltage determining circuit to said first cell.
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Accused Products
Abstract
A gas concentration measuring apparatus is provided which includes a gas concentration sensor consisting of a pump cell, a sensor cell, and a monitor cell. The pump cell works to determine the concentration of O2. The sensor cell works to decompose an oxygen containing gas such as NOx and provide an output indicative of the concentration of NOx. The apparatus also includes an applying voltage determining circuit which looks up a predetermined voltage-to-current relation to determine a target voltage to be applied to the pump cell as a function of the current produced by the pump cell so as to preclude the pump cell from decomposing the oxygen containing gas component, thereby minimizing an error in determining the concentration of oxygen containing gas as a function of the output of the sensor cell.
19 Citations
32 Claims
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1. A gas concentration measuring apparatus comprising:
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a gas concentration sensor including a gas chamber, a first cell responsive to application of a voltage to pump oxygen molecules selectively out of and into gasses admitted into the gas chamber to produce an electric current indicative of a concentration of the oxygen molecules, a second cell working to determine a concentration of a specified oxygen containing gas component contained in the gasses having passed through the first cell, and a monitor cell working to monitor a concentration of residual oxygen molecules within the gas chamber and provide an output indicative thereof;
an applying voltage determining circuit looking up a predetermined voltage-to-current relation to determine a target voltage to be applied to said first cell as a function of the electric current produced by said first cell so as to preclude said first cell from decomposing the specified oxygen containing gas component; and
an applying voltage controlling circuit working to apply the target voltage determined by said applying voltage determining circuit to said first cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A gas concentration measuring apparatus comprising:
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a gas concentration sensor including a gas chamber, a first cell responsive to application of a voltage to pump oxygen molecules selectively out of and into gasses admitted into the gas chamber to produce an electric current indicative of a concentration of the oxygen molecules, a second cell working to determine a concentration of a specified oxygen containing gas component contained in the gasses having passed through the first cell, and a monitor cell working to monitor a concentration of residual oxygen molecules within the gas chamber and provide an output indicative thereof;
an applying voltage correcting circuit working to determine a target voltage to be applied to said first cell by looking up a predetermined voltage-to-current relation as a function of the electric current produced by said first cell, said applying voltage correcting circuit correcting one of the target voltage and the predetermined voltage-to-current relation as a function of the output of said monitor cell; and
an applying voltage controlling circuit working to control voltage applied to said first cell into agreement with the target voltage determined by said applying voltage correcting circuit. - View Dependent Claims (19, 20, 21, 22, 26)
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23. A gas concentration measuring apparatus comprising:
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a gas concentration sensor including a gas chamber, a first cell responsive to an application of voltage to pump oxygen molecules selectively out of and into gasses admitted into the gas chamber to produce an electric current indicative of a concentration of the oxygen molecules, a second cell working to produce an electric current for determining a concentration of a specified oxygen containing gas component contained in the gasses having passed through the first cell, and a monitor cell working to monitor a concentration of residual oxygen molecules within the gas chamber and provide an output indicative thereof;
an applying voltage determining circuit looking up a predetermined voltage-to-current relation to determine a target voltage to be applied to said first cell as a function of the electric current produced by said first cell so as to preclude said first cell from decomposing the specified oxygen containing gas component; and
a second cell output correcting circuit working to correct the electric current outputted by said second cell as a function of the output of said monitor cell. - View Dependent Claims (24, 25)
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27. A gas concentration measuring apparatus comprising:
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a gas concentration sensor including a gas chamber, a first cell responsive to application of a voltage to pump oxygen molecules selectively out of and into gasses admitted into the gas chamber to produce an electric current indicative of a concentration of the oxygen molecules, a second cell working to output an electric current for determining a concentration of a specified oxygen containing gas component contained in the gasses having passed through the first cell, and a monitor cell working to monitor a concentration of residual oxygen molecules within the gas chamber and provide an output indicative thereof;
an applying voltage determining circuit working to determine a target voltage to be applied to said first cell by looking up a predetermined voltage-to-current relation as a function of the electric current produced by said first cell;
a first correcting circuit working to correct on of the target voltage and the predetermined voltage-to-current relation as a function of the output of said monitor cell so as to preclude said first cell from decomposing the specified oxygen containing gas component;
an applying voltage controlling circuit working to control voltage applied to said first cell into agreement with the target voltage provided by said applying voltage correcting circuit; and
a second correcting circuit working to correct the electric current produced by said second cell as a function of the output of said monitor cell to determine the concentration of the specified oxygen containing gas component. - View Dependent Claims (28, 29)
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30. A gas concentration measuring apparatus comprising:
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a gas concentration sensor including a gas chamber, a first cell responsive to an application of a voltage to pump oxygen molecules selectively out of and into gasses admitted into the gas chamber to produce an electric current indicative of a concentration of the oxygen molecules, a second cell working to determine a concentration of a specified oxygen containing gas component contained in the gasses having passed through the first cell, and a monitor cell working to monitor a concentration of residual oxygen molecules within the gas chamber and provide an output indicative thereof, said first cell being formed in a solid electrolyte element;
a resistance determining circuit working to determine a resistance to the solid electrolyte element;
an applying voltage determining circuit working to determine a target voltage to be applied to said first cell by looking up a predetermined voltage-to-current relation as a function of the electric current produced by said first cell;
an applying voltage correcting circuit correcting one of the target voltage and the predetermined voltage-to-current relation as a function of the resistance determined by said resistance determining circuit; and
an applying voltage controlling circuit working to control voltage applied to said first cell into agreement with the target voltage provided by said applying voltage correcting circuit. - View Dependent Claims (31, 32)
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Specification