Air injection control for preheated catalysts
First Claim
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1. A method for admitting a quantity of supplemental air to an exhaust gas path of an internal combustion engine having a supplementally heated exhaust gas treatment means for catalytically treating engine exhaust gas, comprising the steps of:
- detecting a vehicle startup command;
activating supplemental heating of the exhaust gas treatment means upon detecting the vehicle startup command;
sensing temperature of the exhaust gas treatment means;
comparing exhaust gas treatment means temperature to a predetermined temperature;
initiating admission of supplemental air to the exhaust gas path at a commanded rate when the exhaust gas treatment means temperature exceeds the predetermined temperature; and
enabling engine starting after initiating admission of supplemental air to the exhaust gas path.
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Abstract
When a preheater elevates internal combustion engine exhaust gas treatment means temperature above a threshold temperature and prior to and during engine cranking, supplemental air is provided to an internal combustion engine exhaust gas path at a controlled rate responsive to parameters indicating excess engine emission levels during an engine startup period.
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Citations
9 Claims
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1. A method for admitting a quantity of supplemental air to an exhaust gas path of an internal combustion engine having a supplementally heated exhaust gas treatment means for catalytically treating engine exhaust gas, comprising the steps of:
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detecting a vehicle startup command; activating supplemental heating of the exhaust gas treatment means upon detecting the vehicle startup command; sensing temperature of the exhaust gas treatment means; comparing exhaust gas treatment means temperature to a predetermined temperature; initiating admission of supplemental air to the exhaust gas path at a commanded rate when the exhaust gas treatment means temperature exceeds the predetermined temperature; and enabling engine starting after initiating admission of supplemental air to the exhaust gas path. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for controlling, prior to and during an engine startup period including an engine cranking period, a quantity of supplemental air admitted to an internal combustion engine exhaust gas path having an electrical heating element for supplemental heating of an exhaust gas treatment means, comprising the steps of:
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detecting a signal indicating a start of a heating cycle; energizing the electrical heating element to provide for supplemental heating of the exhaust gas treatment means upon detecting the signal; sensing temperature of the exhaust gas treatment means; comparing exhaust gas treatment means temperature to a predetermined temperature; metering supplemental air to the exhaust gas path according to a predetermined metering schedule when exhaust gas treatment means temperature exceeds the predetermined temperature; sensing a rate at which the metered supplemental air passes to the exhaust gas path; comparing the sensed rate to a predetermined rate; and precluding occurrence of engine cylinder events until the sensed rate exceeds the predetermined rate. - View Dependent Claims (8, 9)
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Specification