| 摘要 |
This NOx concentration measurement system is provided with an NOx sensor (2), a detection means (3), an NH3 concentration estimation means (5), and a calculation means (7). The NOx sensor (2) measures the total concentration (c4) of the NOx concentration present in exhaust gases (g) (original NOx concentration (c1)) and the concentration of NO generated by oxidation of NH3 (NH3-derived NO concentration (c3)). The calculation means (7) calculates the NH3-derived NO concentration (c3) from the sensor exterior NH3 concentration (c2), and at least one parameter from among the air-fuel ratio (A/F), the O2 concentration, and the H2O concentration. The original NOx concentration (c1) is then calculated from the total concentration (c4) and the NH3-derived NO concentration (c3). |
