System and method for purging a hydrocarbon trap
AssigneeFord Global Technologies, LLC
InventorDonald J. Lewis
Life of this patent
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Abstract
A method and a system are provided for purging a hydrocarbon trap coupled to an internal combustion engine. An air supply device supplies oxygen to the hydrocarbon trap to facilitate the oxidation of stored hydrocarbons. A controller causes the air supply device to provide the oxygen in pulses instead of in a constant stream. By providing the oxygen in pulses, a sufficient amount of oxygen can be supplied to effectively purge the hydrocarbon trap, while, at the same time, preventing the unheated air from the air supply device from cooling the hydrocarbon trap below its purge threshold temperature.
Claims14
A method for purging a hydrocarbon trap coupled to an engine, comprising:
- determining a quantity of oxygen needed to oxidize hydrocarbons stored in said hydrocarbon trap;
- enabling a supply of oxygen upstream of said hydrocarbon trap based on a hydrocarbon trap temperature;
- and
- regulating said supply of oxygen upstream of said trap to oxidize said hydrocarbons based on an engine operating condition and said determined quantity to reduce lowering said hydrocarbon trap temperature.
A method for purging a hydrocarbon trap coupled to an engine, comprising:
- determining a first quantity of oxygen needed to oxidize hydrocarbons stored in said hydrocarbon trap and to oxidize exhaust gases rich of stoichiometry from said engine;
- and
- supplying a plurality of pulses of oxygen upstream of said trap to oxidize said rich exhaust gases and to maintain a temperature of said trap above a threshold temperature, said pulses further oxidizing said hydrocarbons in said trap, said plurality of pulses corresponding to said first quantity of oxygen.
A system for purging a hydrocarbon trap coupled to an internal combustion engine, comprising:
- a hydrocarbon trap positioned in an exhaust path downstream of the engine;
- an air supply device positioned to supply oxygen upstream of said hydrocarbon trap;
- and
- a controller configured to determine a quantity of oxygen needed to oxidize hydrocarbons stored in said hydrocarbon trap, said controller further configured to enable said supply of oxygen based on said hydrocarbon trap temperature, said controller further configured to regulate said supply of oxygen based on an engine operating and said determined quantity to reduce lowering said hydrocarbon trap temperature.
Dependencies are inferred from the claim text.