Patent ID: 8211293

Claim:
A method of correcting NO x sensor, the method being adapted for correcting an NO x concentration that an NO x sensor detects actually, the NO x sensor being disposed in an exhaust-gas flow passage of vehicle, and comprising a porous diffusion-resistance layer, an exhaust-gas chamber into which exhaust gases that have passed through the porous diffusion-resistance layer are introduced, and a detective unit for detecting an NO x concentration in the exhaust gases that are introduced into the exhaust-gas chamber, the method comprising the steps of: preparing a corrective map in advance, the corrective map recording relationships between temperature physical quantities that are relevant to a temperature of the exhaust gases, oxygen-concentration physical quantities that are relevant to an oxygen concentration in the exhaust gases, and an existing proportion of at least one of NO and NO 2 in a mixture of NO x in the exhaust gases before passing through the porous diffusion-resistance layer; finding the existing proportion with reference to the corrective map using the temperature physical quantities that are detected actually and the oxygen-concentration physical quantities that are detected actually; and correcting the NO x concentration, which the NO x sensor detects actually, on the basis of not only the existing proportion but also a difference between an NO 2 diffusion velocity and an NO diffusion velocity.