System for detecting deterioration of catalyst for purifying exhaust gas
First Claim
1. An exhaust gas purifying catalyst deterioration detecting system comprising:
- calculation means for calculating an amount of exhaust gas component purified in an exhaust gas purifying catalyst disposed in an exhaust system of an internal combustion engine, after a start of said internal combustion engine and before said catalyst reaches a predetermined temperature corresponding to catalyst activation; and
catalyst deterioration detecting means for detecting a deterioration of said catalyst based on the amount of purified gas component calculated by said calculation means.
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Abstract
In a system for detecting deterioration of an exhaust catalyst, when a catalyst temperature exceeds 150° C., the changing widths of the output voltage of an oxygen sensor downstream of the catalyst are integrated for a predetermined sampling period to determine data ΣV reflecting the amount of purified gas component, and the deviation of the air/fuel ratio detected by an air/fuel ratio sensor upstream of the catalyst, and a target A/F and an exhaust gas flow rate or an intake flow rate are multiplied so that data ΣA/F •Q of the fluctuation of the gas component flowing into the catalyst are determined by integrating the multiplied values. At the instant when the catalyst temperature reaches 550° C., the data ΣV, as integrated till then, are compared with a deterioration determining value, as set according to the data ΣA/F•Q, to determine whether the catalyst is deteriorated.
62 Citations
23 Claims
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1. An exhaust gas purifying catalyst deterioration detecting system comprising:
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calculation means for calculating an amount of exhaust gas component purified in an exhaust gas purifying catalyst disposed in an exhaust system of an internal combustion engine, after a start of said internal combustion engine and before said catalyst reaches a predetermined temperature corresponding to catalyst activation; and catalyst deterioration detecting means for detecting a deterioration of said catalyst based on the amount of purified gas component calculated by said calculation means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An exhaust gas purifying catalyst deterioration detecting system comprising:
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calculation means for calculating the amount of exhaust gas component unpurified in an exhaust gas purifying catalyst disposed in an exhaust system of an internal combustion engine, after a start of said engine and before an activation of said catalyst; and catalyst deterioration detecting means for detecting a deterioration of said catalyst as the calculated amount of the unpurified exhaust gas component increases. - View Dependent Claims (20, 21, 22, 23)
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Specification