Patent ID: 6092368
Filing Date: 2000-07-25
Classification: F01N,Y02T

Abstract:
A function diagnostic system for diagnosing functioning of an exhaust gas purifying apparatus of an internal combustion engine system, comprising means including an exhaust gas component sensor having an exhaust gas component detecting function, said exhaust gas component sensor being disposed downstream of the exhaust gas purifying apparatus in the internal combustion engine system, and means for checking the function of said exhaust gas purifying apparatus on the basis of an output of said exhaust gas component sensor located downstream of the exhaust gas purifying apparatus without the need for an upstream exhaust gas component sensor by subjecting the output of said exhaust gas component sensor disposed downstream of the exhaust gas purifying apparatus to an integral processing and checking the function of the exhaust gas purifying apparatus on the basis of the thus-integrated value,wherein said exhaust gas component sensor disposed downstream of the exhaust gas purifying apparatus comprises a sensor capable of detecting hydrocarbons (HC), and wherein the function checking means determines a mean value of HC quantity as:IT=.intg.HC.times.QA.times.(HC to air molecular weight ratio) dt/.intg.VSPdt (g/km)where QA is intake air volume; andVSP is vehicle speed.