US 7,608,176 B2Granted

Gas concentration detecting apparatus

AssigneeDenso Corporation

InventorMitsunobu Niwa

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Abstract

The present invention relates a gas concentration detecting apparatus capable of appropriately making a decision on activation of each of a pump cell, a monitor cell and a sensor cell of its gas concentration sensor. In the apparatus, a control circuit outputs an oxygen concentration value on the basis of a current flowing when a voltage is applied to the pump cell and outputs an NOx concentration value on the basis of a current flowing at the voltage application to the sensor cell. Moreover, the control circuit separately makes a decision on activation of the pump cell and a decision on activation of the sensor cell in the middle of the activation of the sensor. Still moreover, the control circuit makes the decision on the activation of the sensor cell after the activation of the pump cell reaches completion.

Claims15

Dependent claims

A gas concentration detecting apparatus comprising:

a gas sensor further comprising:
a first cell for detecting a concentration of oxygen in a measurement gas, the first cell having a first chamber and a pair of first electrodes, discharging or pumping in oxygen contained in the measurement gas introduced from an external space into the first chamber to generate a pumped measurement gas which contains an excessive oxygen and to output a first electric current indicating the concentration of oxygen in the measurement gas when a first electric voltage is applied between the pair of the first electrodes;
and
a second cell for detecting a concentration of a specific gas in the pumped measurement gas, the second cell having a second chamber and a pair of second electrodes and decomposing the specific gas contained in the pumped measurement gas which is generated by the first cell and is introduced from the first chamber into the second chamber to output a second electric current indicating a concentration of the specific gas in the measurement gas when a second electric voltage is applied between the pair of the second electrodes;
and
a controller that determines a completion of activation of the first cell for allowing to start making use of the first electric current at a first time moment at which a first predetermined period of time elapses after the electric power has been started to be supplied to the first and the second cells to activate at least the one of the first cell and the second cell, and determines a completion of activation of the second cell for allowing to start making use of the second electric current when the second electric current flowing in the second cell of the gas sensor is fallen into a predetermined range and when a predetermined time elapses.

3 more elements

A gas concentration detecting apparatus comprising:

a gas sensor further comprising:
a first cell for detecting a concentration of oxygen in a measurement gas, the first cell having a first chamber and a pair of first electrodes, discharging or pumping in oxygen contained in the measurement gas introduced from an external space into the first chamber to generate a pumped measurement gas which contains an excessive oxygen and to output a first electric current indicating the concentration of oxygen in the measurement gas when a first electric voltage is applied between the pair of the first electrodes;
a second cell for detecting a concentration of a specific gas in the pumped measurement gas, the second cell having a second chamber and a pair of second electrodes and decomposing the specific gas contained in the pumped measurement gas which is generated by the first cell and is introduced from the first chamber into the second chamber to output a second electric current indicating a concentration of the specific gas in the measurement gas when a second electric voltage is applied between the pair of the second electrodes;
and
a third cell for detecting a residual oxygen concentration of said measuring gas after passing through said first cell, the third cell outputting a third electric current indicating the residual oxygen concentration in the measurement gas when a third electric voltage is applied thereto;
and
a controller that determines a completion of activation of the first cell for allowing to start making use of the first electric current at a first time moment at which a first predetermined period of time elapses after the electric power has been started to be supplied to at least the first and the second cells to activate at least the one of the first cell and the second cell, and determines a completion of activation of the second cell for allowing to start making use of the second electric current when the third electric current flowing in the third cell of the gas sensor is fallen into a predetermined range and when a predetermined time elapses.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/681,138Filed 9 Oct 2003
Priority: JP 2002-29777210 Oct 2002
Published: US 2004/0074773 A122 Apr 2004
Granted: 27 Oct 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G01N 27/419
Using cells , i.e. more than one cell and probes with solid electrolytes: measuring voltages or currents with a combination of oxygen pumping…
G01N 27/4071
For investigating or analysing gases: using sensor elements of laminated structure
G01N
Investigating or analysing materials by determining their chemical or physical properties

Family

US 2004/0074773 A1Pre-grant publication · published 22 Apr 2004
US 7,608,176 B2This patent

From the US filing history. Foreign family members aren’t listed.

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