Gas sensor, gas concentration detecting system and related manufacturing method

Abstract

A gas sensor, a gas concentration detection system and a method of manufacturing the gas concentration detection system are disclosed. A gas sensor carries an individual information identifying section, which stores unique individual information related to the gas sensor. The individual information identifying section includes a two-dimensional information code readable with an image recognition device. The individual information identifying section includes a two-dimensional information code readable with an image recognition device. The gas concentration detecting system comprises, in addition to the gas sensor and the image recognition device, an engine control unit operative to correct a sensor output readout value, which is actually read out from the gas sensor, depending on information related to a sensor output value included in the information code.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments according to the present invention with reference to the accompanying drawings, in which:

FIG. 1 is an illustrative view showing a gas sensor of a first embodiment according to the present invention;

FIG. 2 is an illustrative view showing a gas concentration detecting system employing the gas sensor of the first embodiment shown in FIG. 2 for typically illustrating how the gas concentration detecting system reads out information from an information code of the gas sensor and writes the resulting information in an engine control system;

FIG. 3 is a graph showing a characteristic of the gas sensor of the first embodiment, composed of a limiting current type gas sensor, in which an applied voltage is plotted on a transverse axis and a sensor output value, represented with a current value, which is plotted on a longitudinal axis;

FIG. 4 is a graph showing a relational map in which an air fuel ratio (A/F) of an engine is plotted on a transverse axis and a sensor output value (mA) is plotted on a longitudinal axis;

FIG. 5 is an illustrative view typically showing a storage status of unique individual information in an information code of the gas sensor of the first embodiment shown in FIG. 1;

FIG. 6 is an illustrative view showing a gas sensor of a second embodiment according to the present invention;

FIG. 7 is an illustrative view showing a gas sensor of a third embodiment according to the present invention;

FIG. 8 is a graph showing how variations of a sensor output readout value are improved using the gas sensor provided with the information code; and

FIG. 9 is a graph showing how the variations of the sensor output readout value are improved upon performing correcting operation using the information code and correcting operation using an atmospheric air learning method.

Claims

1. A gas sensor, comprising: a gas sensor body for detecting a gas concentration in measuring gases; andan individual information identifying section, associated with the gas sensor body, which stores individual information related to the gas sensor;the individual information identifying section including a two-dimensional information code readable with an image recognition device.

2. The gas sensor according to claim 1, wherein: the two-dimensional information code comprises a QR code readable in first and second directions including a longitudinal direction and a lateral direction.

3. The gas sensor according to claim 1, wherein: the individual information includes information related to a sensor output value which the gas sensor generates depending on variation in gas concentration to be detected.

4. The gas sensor according to claim 1, wherein: the information related to the sensor output value includes information as a sensor output correcting value representing at least one of a sensor output characteristic value of the gas sensor or a deviation of the sensor output characteristic value with respect to a theoretical sensor output value.

5. The gas sensor according to claim 1, wherein: the gas sensor comprises a critical current type gas sensor;wherein the critical current type gas sensor includes a solid electrolyte body having an oxygen ion conductivity and having both sides formed with a pair of electrodes, respectively, to which a voltage is applied to cause critical current to flow such that a current value, flowing across the pair of electrodes, is measured for detecting an air fuel ratio in an internal combustion engine; andwherein the information on the sensor output value or the sensor output correcting value includes at least one of information on a point at a theoretical air fuel ratio region, information on a point in a rich fuel side region and information on a point in a lean fuel side region.

6. The gas sensor according to claim 4, wherein: the gas sensor comprises an oxygen concentration electromotive force type gas sensor;wherein the oxygen concentration electromotive force type gas sensor includes a solid electrolyte body having an oxygen ion conductivity and having both sides formed with a pair of electrodes, respectively, between which an electromotive force appears depending on a difference in an oxygen concentration and is measured for detecting an air fuel ratio in an internal combustion engine; andwherein the information on the sensor output value or the sensor output correcting value includes at least one of information on a point in a rich fuel side region and information on a point in a lean fuel side region.

7. The gas sensor according to claim 1, wherein: the individual information includes at least one of a responsiveness of the gas sensor, an internal resistance, a heater resistance and a sensor activity time.

8. The gas sensor according to claim 1, wherein: the individual information includes production information of the gas sensor.

9. The gas sensor according to claim 1, wherein: the gas sensor body has a lead wire section having a distal end coupled to a connector;wherein the individual information is provided on at least one of the lead wire section and the connector.

10. A gas concentration detecting system, comprising: a gas sensor for detecting a gas concentration in measuring gases and having an individual information identifying section including an information code which stores individual information related to the gas sensor;an image recognition device operative to read out the individual information from the information code; andan engine control unit operative to correct a sensor output readout value, which is actually read out from the gas sensor, depending on information related to a sensor output value included in the information code.

11. The gas concentration detecting system according to claim 10, wherein: the engine control unit is configured in a structure so as to measure an on-endurance sensor output value, resulting from measuring atmospheric air as measuring gas, when the gas sensor is used for a given period of time after the sensor output readout value has been corrected for thereby correcting the sensor output readout value again using the on-endurance sensor output value.

12. A method of manufacturing a gas concentration detecting system adapted to detect a gas concentration in measuring gases, comprising the steps of: preparing a gas sensor having an information code storing unique individual information;reading out the individual information from the information code of the gas sensor with a computer using an image recognition device; andwriting the individual information, read out by the computer, into an engine control unit, with which the gas sensor is associated, using a writing device.

13. The method of manufacturing the gas concentration detecting system according to claim 12, wherein: the information code stores information related to a sensor output value as a sensor output correction value X representing a deviation value on a sensor output characteristic value Ib specific to the gas sensor in terms of a sensor output theoretical value Ia on a relational map; andwherein the sensor output correction value X is expressed as X=(Ib−Ia)/Ia×100 [%].