Abnormality diagnosis method of the NOx sensor, the NOx sensor abnormality diagnosis system, and NOx emissions concentration estimation method for an internal combustion engine

摘要

PROBLEM TO BE SOLVED: To provide a method and system for diagnosing a fault of a NOx sensor, configured to compare a calculated NOx concentration value with a value detected by a NOx sensor to continuously diagnose a fault of the NOx sensor, and to provide an internal combustion engine.;SOLUTION: NOx concentration NOx_cyl is calculated on the basis of a value m_air detected by an intake amount sensor 31 arranged in an intake passage 12 of an internal combustion engine 10, a value Ti detected by a first temperature sensor 32 arranged in an intake manifold 11a, a value Pi detected by a first pressure sensor 33 arranged in the intake manifold 11a, a value Te detected by a second temperature sensor 34 arranged in an exhaust manifold 11b, a value Pe detected by a second pressure sensor 35 arranged in the exhaust manifold 11b, and a value λ_egr detected by an excess air ratio sensor 36 in an exhaust passage 18. The calculated NOx concentration NOx_cyl is compared with the value NOx_m detected by a NOx sensor 37, to determine a fault of the NOx sensor 37 arranged in the exhaust passage 18.;COPYRIGHT: (C)2013,JPO&INPIT