Nitrogen oxide analyzer and method for setting parameter applied to nitrogen oxide analyzer
AssigneeHoriba, Ltd.
InventorHiroshi Nakamura
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Abstract
The nitrogen oxide analyzer obtains the ozone concentration-luminescence response characteristics that show the relationship between the ozone concentration and the light intensity by chemiluminescent response obtained by varying the ozone concentration alone in a steady state, and sets the relationship of the parameter that determines an average period of the sample gas passing the reactor so that the luminescence response is generated in the reactor alone even though the ozone concentration of the ozone-containing gas changes within a predetermined range based on the ozone concentration-luminescence response characteristics.
Claims10
A nitrogen oxide analyzer comprising:
- a reactor where ozone-containing gas and sample gas continuously introduced in a time-series order are mixed and the mixed gas is passed out through an output port;
- a photo detector that detects light intensity of chemiluminescence caused by mixing the ozone-containing gas and the sample gas in the reactor;
- an information processing unit that calculates concentration of nitrogen oxide in the sample gas based on the light intensity detected by the light detector;
- and
- wherein the information processing unit comprises:
- a response characteristics obtaining part that obtains ozone concentration-luminescence response characteristics, which are determined by a relationship between the ozone concentration and the light intensity, by the chemiluminescent response obtained by varying the ozone concentration alone in a steady state wherein reference sample gas containing nitrogen oxide with constant concentration and reference ozone gas with known ozone concentration pass at a constant flow rate and the pressure in the reactor is kept constant;
- and
- a parameter calculating part that calculates a relationship of parameters that determines an average resident time of the sample gas in the reactor based on the ozone concentration-luminescence response characteristics.
A vehicle-mountable nitrogen oxide analyzer comprising:
- a reactor where ozone-containing gas and exhaust gas continuously introduced in a time-series order are mixed and the mixed gas is passed out through an output port;
- a photo detector that detects intensity of light generated in the reactor by mixing the ozone-containing gas and the exhaust gas;
- an information processing unit that calculates the nitrogen oxide concentration in the exhaust gas based on the light intensity detected by the photo detector;
- and
- an ozone generator that introduces atmospheric air without dehumidification and that generates the ozone-containing gas by converting oxygen in the atmospheric air into ozone.
A parameter setting method that is applied to a nitrogen oxide analyzer including a reactor where ozone-containing gas and sample gas continuously introduced in a time-series order are mixed and the mixed gas is passed out through an output port, and a photo detector that detects light intensity of chemiluminescence caused by mixing the ozone-containing gas and the sample gas in the reactor so as to calculate the nitrogen oxide concentration in the sample gas based on the light intensity, the method comprising:
- producing a steady state by flowing reference sample gas containing nitrogen oxide with constant concentration and reference ozone gas with known concentration at a certain flow rate with the pressure in the reactor constant so as to produce the steady state;
- obtaining response characteristics by changing the ozone concentration alone in the steady state and by obtaining ozone concentration-luminescence response characteristics showing a relationship between the ozone concentration and the light intensity by the chemiluminescent response obtained by varying the ozone concentration alone;
- and
- setting parameters by setting a relationship of parameters that determines an average resident time of the sample gas in the reactor so that the luminescence response is generated almost only in the reactor even though the ozone concentration of the ozone-containing gas changes within a predetermined range based on the ozone concentration-luminescence response characteristics.
Dependencies are inferred from the claim text.