Abstract: An exhaust gas analysis method comprises applying a laser beam to the exhaust gas discharged from an internal combustion engine, receiving the laser beam that has passed through the exhaust gas, and measuring the concentration of any of the components contained in the exhaust gas based on the received laser beam. The exhaust gas analysis method further comprises detecting the absorption spectrum of the laser beam absorbed in the exhaust gas by using the received laser beam, calculating the concentration of the specific gas component by using the absorption spectrum, calculating the temperature of the exhaust gas by using the absorption spectrum, calculating the pressure of the exhaust gas by using the absorption spectrum, correcting the calculated concentration of the component contained in the exhaust gas by using the calculated temperature, correcting the concentration by using the calculated pressure, and outputting the true concentration value.

Abstract: An exhaust gas analyzer of the present invention includes a sensor unit 11 installed in an exhaust path from an engine, applies laser light to exhaust gas emitted from the engine and receives laser light that has passed through the exhaust gas so as to measure the concentration of a component contained in the gas based on the received laser light. To an aperture 16 formed in a sensor base 15 of the sensor unit 11, an adjustment ring 40 in a circumferential face of which small holes 41 serving as a laser light passage portion is formed and whose inner circumferential face serves as an exhaust gas passage opening 21 is detachably fitted, whereby the sensor unit can be attached so as to conform to different inner diameters of exhaust tubes.

Abstract: This invention provides a hydrocarbon concentration measuring apparatus, which, even when the concentration and composition of hydrocarbons contained in an object gas to be measured vary, can measure the concentration of the hydrocarbons with good response and good accuracy, and a hydrocarbon measuring method. Light with a waveband including a common absorption region, which is absorbed by a single or a plurality of chemical species, is applied to the object gas by an infrared irradiation equipment. The light applied to the object gas is detected with a line sensor. The absorbance in the common absorption region of the object gas is computed with an analyzer based on the detected light. The sum of concentrations of chemical species, which absorb light in the waveband in the common absorption region, in the single or plurality of chemical species contained in the object gas, is computed with the analyzer based on the absorbance.

Abstract: An exhaust gas analysis method comprises applying a laser beam to the exhaust gas discharged from an internal combustion engine, receiving the laser beam that has passed through the exhaust gas, and measuring the concentration of any of the components contained in the exhaust gas based on the received laser beam. The exhaust gas analysis method further comprises detecting the absorption spectrum of the laser beam absorbed in the exhaust gas by using the received laser beam (S1), calculating the concentration of the specific gas component by using the absorption spectrum (S2), calculating the temperature of the exhaust gas by using the absorption spectrum (S3), calculating the pressure of the exhaust gas by using the absorption spectrum (S4 to S6), correcting the calculated concentration of the component contained in the exhaust gas by using the calculated temperature (S7), correcting the concentration by using the calculated pressure (S8), and outputting the true concentration value (S9).

Abstract: An exhaust gas analyzer of the present invention includes a sensor unit 11 installed in an exhaust path from an engine, applies laser light to exhaust gas emitted from the engine and receives laser light that has passed through the exhaust gas so as to measure the concentration of a component contained in the gas based on the received laser light. To an aperture 16 formed in a sensor base 15 of the sensor unit 11, an adjustment ring 40 in a circumferential face of which small holes 41 serving as a laser light passage portion is formed and whose inner circumferential face serves as an exhaust gas passage opening 21 is detachably fitted, whereby the sensor unit can be attached so as to conform to different inner diameters of exhaust tubes.