GAS CONCENTRATION DETECTION APPARATUS
First Claim
1. A gas concentration detection apparatus comprising:
- an oxygen pump cell for discharging excess oxygen from a measurement target gas in accordance with voltage application;
a gas concentration detection cell for detecting the concentration of a specific gas component in the gas from which the excess oxygen is discharged by the oxygen pump cell, and outputting a current value according to the detected concentration;
acquisition means which, when the oxygen pump cell and the gas concentration detection cell are being warmed up and when excess oxygen is being discharged, acquires the time at which an inflection point appears in the output of the gas concentration detection cell; and
activity judgment means which regards the time acquired by the acquisition means at which the inflection point appears as an activity time of the gas concentration detection cell.
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Accused Products
Abstract
It is an object of the present invention to provide a gas concentration detection apparatus that is capable of forming an accurate activity judgment when a gas concentration detection cell begins to detect gas concentration with high accuracy. When warm-up begins at time t0 in a NOx concentration detection apparatus that achieves NOx concentration detection with a NOx sensor cell after excess oxygen is discharged by an oxygen pump cell, a NOx sensor cell output begins to rise at time t1. Subsequently, at time t2, an oxygen pump cell output begins to rise. An inflection point appearing in the NOx sensor cell output is then located. At time t5 at which the inflection point appears, an activity judgment about the NOx sensor cell is formed.
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Citations
22 Claims
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1. A gas concentration detection apparatus comprising:
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an oxygen pump cell for discharging excess oxygen from a measurement target gas in accordance with voltage application; a gas concentration detection cell for detecting the concentration of a specific gas component in the gas from which the excess oxygen is discharged by the oxygen pump cell, and outputting a current value according to the detected concentration; acquisition means which, when the oxygen pump cell and the gas concentration detection cell are being warmed up and when excess oxygen is being discharged, acquires the time at which an inflection point appears in the output of the gas concentration detection cell; and activity judgment means which regards the time acquired by the acquisition means at which the inflection point appears as an activity time of the gas concentration detection cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A gas concentration detection apparatus comprising:
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excess oxygen removal means for removing excess oxygen from a measurement target gas; a gas concentration detection cell for detecting the concentration of a specific gas component in the gas from which the excess oxygen is removed by the excess oxygen removal means; and activity judgment means which, when the excess oxygen removal means and the gas concentration detection cell are being warmed up and when excess oxygen is being removed, regards the time at which an inflection point appears in the concentration of the specific gas component detected by the gas concentration detection cell as an activity time of the gas concentration detection cell.
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22. A gas concentration detection apparatus comprising:
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an oxygen pump cell for discharging excess oxygen from a measurement target gas in accordance with voltage application; a gas concentration detection cell for detecting the concentration of a specific gas component in the gas from which the excess oxygen is discharged by the oxygen pump cell, and outputting a current value according to the detected concentration; acquisition device which, when the oxygen pump cell and the gas concentration detection cell are being warmed up and when excess oxygen is being discharged, acquires the time at which an inflection point appears in the output of the gas concentration detection cell; and activity judgment device which regards the time acquired by the acquisition device at which the inflection point appears as an activity time of the gas concentration detection cell. the gas concentration detection cell.
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Specification