Patent ID: 6792346
Filing Date: 2004-09-14
Classification: F01N,F02B,F02D,Y02T

Abstract:
A diagnostic apparatus for an engine, comprisingcatalyst temperature detecting means for detecting a value associated with the temperature of an exhaust-gas purification catalyst disposed in an exhaust system of the engine; catalyst warming means for correcting a plurality of control parameters for the engine, so as to activate the exhaust-gas purification catalyst, when the exhaust-gas purification catalyst is determined to be inactivated based upon the detection of said catalyst temperature detecting means; cumulative fuel consumption calculating means for calculating a value associated with cumulative fuel consumption during a time period after engine start until the elapse of a cumulating time period; and failure judging means for judging whether said catalyst warming means is faulty, wherein a faulty condition occurs when the cumulative fuel consumption is judged to be equal to or less than a judgement threshold based on the calculation of said cumulative fuel consumption calculating means.