ABGASEMISSIONSSTEUERUNG FÜR EINE BRENNKRAFTMASCHINE
An engine exhaust emission control arrangement has a catalytic converter including a three-way catalyst. A first oxygen sensor detects an oxygen concentration of exhaust gas upstream of the catalyst and a second oxygen sensor detects an oxygen concentration of exhaust gas downstream of the catalyst....
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Main Authors | , , |
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Format | Patent |
Language | German |
Published |
06.06.2007
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Subjects | |
Online Access | Get full text |
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Summary: | An engine exhaust emission control arrangement has a catalytic converter including a three-way catalyst. A first oxygen sensor detects an oxygen concentration of exhaust gas upstream of the catalyst and a second oxygen sensor detects an oxygen concentration of exhaust gas downstream of the catalyst. A microprocessor calculates a specific period oxygen storage amount of a catalyst while the upstream oxygen concentration is higher than the stoichiometric concentration and the downstream oxygen concentration is in a predetermined concentration range which has a value approximately equal to the stoichiometric oxygen concentration. The microprocessor also calculates a specific period oxygen release amount of a catalyst while the upstream oxygen concentration is lower than the stoichiometric concentration and the downstream oxygen concentration produces an indication of a predetermined concentration range. A specific period oxygen storage amount is sampled at a time at which the downstream oxygen concentration becomes greater than the predetermined concentration range as a maximum oxygen storage amount and a specific period oxygen release amount is sampled at a time at which the downstream oxygen concentration becomes smaller than the predetermined concentration range as a maximum oxygen release amount. The engine air-fuel ratio is controlled to cause the oxygen storage amount of the catalyst to coincide with a target value which is set at approximately half of an average value of the maximum oxygen storage amount and the maximum oxygen release amount. |
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Bibliography: | Application Number: DE20016026022T |