Exhaust gas analyzer, and exhaust gas analysis method

An exhaust gas analysis method for analyzing exhaust gas discharged from an internal combustion engine via an exhaust pipe connected to the internal combustion engine and having a catalyst disposed therein, comprising:

• irradiating infrared light to the exhaust gas;
• detecting the infrared light after passing through the exhaust gas;
• generating a detection signal on a basis of the detected infrared light;
• calculating a carbon dioxide (CO2) concentration in the exhaust gas on a basis of the detection signal;
• and
• calculating an oxygen (O2) concentration in the exhaust gas from the CO2 concentration by using a fuel combustion reaction equation, an EGR rate in an exhaust gas recirculation system or a value related to the EGR rate, a value indicating an oxygen desorption amount or oxygen absorption amount by the catalyst, a conversion coefficient obtained from a ratio of an O2 coefficient and a CO2 coefficient in the fuel combustion reaction equation, an EGR correction coefficient obtained from the EGR rate or a value related to the EGR rate, a catalyst correction coefficient obtained from a value indicating an oxygen desorption amount or oxygen absorption amount by the catalyst, and a CO2 concentration variation such that the O2 concentration that does not absorb the infrared light is measured.

An exhaust gas analyzer to analyze exhaust gas discharged from an internal combustion engine, comprising:

• an infrared light source to irradiate infrared light to the exhaust gas;
• a photodetector to detect the infrared light after passing through the exhaust gas;
• and
• a processor to calculate a CO2 concentration in the exhaust gas on a basis of a detection signal obtained by the photodetector, and to calculate an O2 concentration in the exhaust gas from pretrained data generated from training data comprising a CO2 concentration and an O2 concentration in the exhaust gas and expressing a correlation between the CO2 concentration and the O2 concentration in the exhaust gas, and from the CO2 concentration calculated by the processor such that the exhaust gas analyzer measures the O2 concentration that does not absorb the infrared light.

An exhaust gas analyzer to analyze exhaust gas discharged from an internal combustion engine, comprising:

• an infrared light source to irradiate infrared light to the exhaust gas;
• a photodetector to detect the infrared light after passing through the exhaust gas;
• a processor to calculate a CO2 concentration in the exhaust gas on a basis of a detection signal obtained by the photodetector, and to calculate an O2 concentration in the exhaust gas from the CO2 concentration by using a fuel combustion reaction equation and an EGR rate in an exhaust gas recirculation system or a value related to the EGR rate such that the exhaust gas analyzer measures the O2 concentration that does not absorb the infrared light, wherein the fuel combustion reaction equation indicates a relationship between CO2 and H2O generated during fuel combustion;
• and;
• a catalyst disposed in an exhaust pipe connecting to the internal combustion engine so as to analyze exhaust gas after passing through the catalyst, wherein
• the processor calculates the O2 concentration in the exhaust gas by using a value indicating an oxygen desorption amount or oxygen absorption amount by the catalyst, a conversion coefficient obtained from a ratio of an O2 coefficient and a CO2 coefficient in the fuel combustion reaction equation, an EGR correction coefficient obtained from the EGR rate or a value related to the EGR rate, a catalyst correction coefficient obtained from a value indicating an oxygen desorption amount or oxygen absorption amount by the catalyst, and a CO2 concentration variation calculated by the processor.