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(11) | EP 2 581 576 A8 |
(12) | CORRECTED EUROPEAN PATENT APPLICATION |
published in accordance with Art. 153(4) EPC |
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(54) | EXHAUST GAS PURIFICATION SYSTEM FOR INTERNAL COMBUSTION ENGINE |
(57) An exhaust purification system of an internal combustion engine is provided with
an exhaust purification catalyst where NOx which is contained in exhaust gas and modified hydrocarbons react. The exhaust purification
catalyst carries precious metal catalysts and is formed with a basic exhaust gas flow
surface part. The exhaust purification catalyst has the property of reducing NOx if making the concentration of hydrocarbons which flow into the exhaust purification
catalyst vibrate by within a predetermined range of amplitude and within a predetermined
range of period. The system estimates the holding ability by which the NOx in the exhaust gas is held on the basic exhaust gas flow surface part of the exhaust
purification catalyst and, when the holding ability becomes less than a predetermined
judgment value of the holding ability, makes the concentration of hydrocarbons which
flow into the exhaust purification catalyst rise.
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