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US 12,656,308 B2Granted
Gas concentration measuring device and manufacturing method for the same
AssigneeDenso Corporation
InventorsYusuke Kawamoto, Yusuke Todo, Hiroo Imamura, Mitsunobu Nakato
Life of this patent
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Abstract
A gas sensor, an oxygen concentration measuring unit, and a computation unit are included. The gas sensor measures a concentration CNOX of specific gas contained in measured gas. The oxygen concentration measuring unit measures a concentration CO2 of oxygen in the measured gas outside the gas sensor. The gas sensor has a measured gas chamber, a reference gas chamber, a diffusion resistance unit, a pump cell, and a sensor cell. The computation unit computes a concentration CNOX of the specific gas by using the concentration CO2 of oxygen measured by using the oxygen concentration measurement unit and the sensor current.
Claims16
A gas concentration measuring device, comprising:
- a gas sensor configured to measure a concentration CNOX of specific gas contained in measured gas;
- an oxygen concentration measuring unit configured to measure a concentration CO2 of oxygen in the measured gas;
- and
- a computation unit configured to compute the concentration CNOX of the specific gas,
- wherein
- the gas sensor includes:
- a measured gas chamber into which the measured gas is to be introduced,
- a reference gas chamber into which reference gas is to be introduced,
- a diffusion resistance unit configured to regulate a flow velocity of the measured gas to be introduced into the measured gas chamber,
- a pump cell configured to move oxygen from the measured gas chamber into the reference gas chamber, and
- a sensor cell configured to cause a sensor current I to flow therethrough correspondingly to the concentration CNOX of the specific gas in the measured gas chamber, wherein
- the computation unit is configured to compute the concentration CNOX of the specific gas by using a measured value of the concentration CO2 of oxygen with the oxygen concentration measuring unit and a measured value of the sensor current I,
- the gas concentration measuring device is configured for mounting on a vehicle, the gas sensor is configured to be operatively coupled to an exhaust pipe, the gas sensor is configured to measure the concentration CNOX contained in exhaust gas emitted from the exhaust pipe, and the computed concentration CNOX of the specific gas is used in association with the gas sensor,
- an area of the diffusion resistance unit on a plane orthogonal to an introduction direction of the measured gas is S,
- a length of the diffusion resistance unit in the introduction direction is L,
- pressure of the measured gas outside the gas sensor is P,
- temperature of the diffusion resistance unit is T,
- a diffusion coefficient of the measured gas is D, and
- A and β are constants, wherein
- the computation unit is configured to compute the concentration CNOX of the specific gas by using the measured value of the concentration CO2 of oxygen and the measured value of the sensor current I and by using the equation (1)
- (
- equation
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- NOX
-
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- D
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- β
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- P
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- ln
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65 more elements
A gas concentration measuring device, comprising:
- a gas sensor configured to measure a concentration CNOX of specific gas contained in measured gas;
- an oxygen concentration measuring unit configured to measure a concentration CO2 of oxygen in the measured gas;
- and
- a computation unit configured to compute the concentration CNOX of the specific gas,
- wherein
- the gas sensor includes:
- a measured gas chamber into which the measured gas is to be introduced,
- a reference gas chamber into which reference gas is to be introduced,
- a diffusion resistance unit configured to regulate a flow velocity of the measured gas to be introduced into the measured gas chamber,
- a pump cell configured to move oxygen from the measured gas chamber into the reference gas chamber, and
- a sensor cell configured to cause a sensor current I to flow therethrough correspondingly to the concentration CNOX of the specific gas in the measured gas chamber, wherein
- the computation unit is configured to compute the concentration CNOX of the specific gas by using a measured value of the concentration CO2 of oxygen with the oxygen concentration measuring unit and a measured value of the sensor current I,
- an area of the diffusion resistance unit on a plane orthogonal to an introduction direction of the measured gas is S,
- a length of the diffusion resistance unit in the introduction direction is L,
- pressure of the measured gas outside the gas sensor is P,
- temperature of the diffusion resistance unit is T,
- a diffusion coefficient of the measured gas is D, and
- A and β are constants, wherein
- the computation unit is configured to compute the concentration CNOX of the specific gas by using the measured value of the concentration CO2 of oxygen and the measured value of the sensor current I and by using the equation (1),
- (equation (1))
- I=A P/T S/L CNOX[D+1/βP CO2ln(1−CO2)] (1)
18 more elements
Dependencies are inferred from the claim text.