Measuring NOx concentration
AssigneeRiken
InventorsYunzhi Gao, Akira Kunimoto, Yongtie Yan, Hideyuki Kurosawa, Yukio Nakanouchi, Norio Miura, Noboru Yamazoe, Masaharu Hasei
Life of this patent
Estimating the term…
Abstract
A gas sensor for measuring concentration of a gas component in a measured gas, including a solid electrolytic substrate and at least two electrodes fixed to the substrate. At least a first electrode of the electrodes is disposed in the environment of the measurement gas, at least one of electrodes is polarized by applying a bias current or bias voltage, and a change in the potential of the polarized electrode is measured to thereby measure the concentration of the target gas.
Claims4
A method for measuring concentration of NOx in a target gas, comprising the steps of:
- exposing a first electrode to the target gas and a second electrode to an atmospheric air, wherein said first and second electrodes are fixed to the same ion conductive solid electrolytic substrate;
- passing a bias current between said first electrode and said second electrode using a constant-current source such that the polarization potential of said first electrode falls within a range of −0.3˜0.4V (exclusive of 0V);
- and
- detecting an electromotive force generated across said first electrode and said second electrode while passing said bias current between said first electrode and said second electrode.
A method for measuring concentration of NOx in a target gas, comprising a step of:
- exposing first and second electrodes to the target gas, wherein said first and second electrodes are fixed to the same ion conductive solid electrolytic substrate;
- passing a bias current between said first electrode and said second electrode using a constant-current source such that the polarization potential of said first electrode and said second electrode falls within a range of 0.05˜0.5V and −0.03˜0.5V respectively;
- and
- detecting an electromotive force generated across said first electrode and said second electrode while passing said bias current between said first electrode and said second electrode.
A method for measuring concentration of NOx in a target gas, comprising a step of:
- exposing a first electrode to the target gas and a second electrode to said target gas or an atmospheric air, wherein said first and second electrodes are fixed to the same ion conductive solid electrolytic substrate;
- passing a bias current between said first electrode and a third electrode using a constant-current source such that the polarization potential of said first electrode falls within a range of −0.3˜0.4V (exclusive of 0V), wherein said third electrode is fixed to the same ion conductive solid electrolytic substrate as said first and second electrodes;
- and
- detecting an electromotive force generated across said first electrode and said second electrode while passing said bias current between said first electrode and said third electrode.
A method for measuring concentration of NOx in a target gas, comprising a step of:
- exposing first and second electrodes to the target gas, wherein said first and second electrodes are fixed to the same ion conductive solid electrolytic substrate;
- passing a bias current between said first electrode and a third electrode, and said second electrode and said third electrode using a constant-current source such that the polarization potential of said first electrode and said second electrode falls within a range of 0.05˜0.5V and −0.03˜0.5V respectively, wherein said third electrode is fixed to the same ion conductive solid electrolytic substrate as said first and second electrodes;
- and
- detecting an electromotive force generated across said first electrode and said second electrode while passing said bias current between said first electrode and said third electrode.
Dependencies are inferred from the claim text.