Patent ID: 7260928
Filing Date: 2007-08-28
Classification: F01N,Y02T

Abstract:
1. A diagnostic device for a secondary air control system for an internal combustion engine, the secondary air control system supplying secondary air to an upstream of a catalyst in an exhaust passage of the internal combustion engine, the catalyst purifying exhaust gas, the diagnostic device comprising: a secondary air detecting means that detects secondary air information, which relates to at least one of a flow amount of secondary air and pressure of secondary air; an abnormality diagnostic means that performs an abnormality diagnostic operation of the secondary air control system in accordance with the secondary air information detected using the secondary air detecting means; a voltage detecting means that detects power source voltage information, which relates to power source voltage supplied to the secondary air control system; and an evaluating condition correcting means that corrects an evaluating condition for evaluating abnormality in the secondary air control system, wherein the evaluating condition correcting means corrects the evaluating condition in accordance with the power source voltage information, which is detected using the voltage detecting means, and wherein the secondary air detecting means and the voltage detecting means respectively detect the secondary air information in a plurality of detecting periods and the power source voltage information in a plurality of detecting periods, the evaluating condition correcting means corrects the evaluating condition, which is for evaluating abnormality in the secondary air control system, in accordance with the power source voltage information in the plurality of detecting periods, and the abnormality diagnostic means performs the abnormality diagnostic operation of the secondary air control system in accordance with the secondary air information in the plurality of the detecting periods.