Hydrocarbon retaining and purging system for flex-fuel combustion engine
First Claim
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1. A method for an engine comprising:
- selectively routing exhaust gases through a hydrocarbon retaining system to store exhaust hydrocarbons;
selectively purging stored hydrocarbons from the hydrocarbon retaining system to an engine intake, the selective purging initiated responsive to an alcohol content of an injected fuel; and
varying termination of the selective routing responsive to the alcohol content of the injected fuel by delaying the termination as the alcohol content increases.
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Abstract
Systems, methods, and computer readable storage media are described in which exhaust gas is routed to a hydrocarbon retaining device during starting, and purged to the engine intake manifold. Various alternative approaches are described for controlling operation and diagnosing degradation. Further, various interrelated configurations are described.
54 Citations
17 Claims
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1. A method for an engine comprising:
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selectively routing exhaust gases through a hydrocarbon retaining system to store exhaust hydrocarbons; selectively purging stored hydrocarbons from the hydrocarbon retaining system to an engine intake, the selective purging initiated responsive to an alcohol content of an injected fuel; and varying termination of the selective routing responsive to the alcohol content of the injected fuel by delaying the termination as the alcohol content increases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for a vehicle including an engine having an intake and an exhaust, the system comprising:
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a fuel system of the vehicle; a hydrocarbon retaining system selectively coupled to the engine intake, engine exhaust, and fuel system; and a controller with code for, selectively routing exhaust gases of the engine to the hydrocarbon retaining system to store exhaust hydrocarbons; selectively routing fuel vapors from the fuel system to the hydrocarbon retaining system; selectively purging stored hydrocarbons from the hydrocarbon retaining system to the engine intake; and varying an initiating of the selective purging and varying an ending of the routing to store exhaust hydrocarbons responsive to at least an alcohol content of fuel combusted in the engine, the varying including delaying ending of hydrocarbon storage and delaying initiating of hydrocarbon purging to higher exhaust temperatures as the alcohol content in the fuel increases.
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17. A system for a vehicle including an engine having an intake and an exhaust, the system comprising:
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a fuel system of the vehicle; a catalytic emission control device closely coupled in the exhaust; a hydrocarbon retaining system selectively coupled to the engine intake, engine exhaust, and fuel system, the hydrocarbon retaining system having a vent positioned adjacent at least a portion of the exhaust of the engine; and a controller for selectively routing exhaust gases of the engine to the hydrocarbon retaining system to store exhaust hydrocarbons;
selectively routing fuel vapors from the fuel system to the hydrocarbon retaining system;
selectively purging stored hydrocarbons from the hydrocarbon retaining system to the engine intake by inducting fresh air into the vent;
varying an initiating of the selective purging of stored hydrocarbons responsive to a temperature of the emission control device; and
varying an ending of the routing to store exhaust hydrocarbons responsive to at least an alcohol content of fuel combusted in the engine, wherein the controller includes further code for,as the alcohol content of the fuel increases, increasing a temperature threshold of exhaust gas routing through the hydrocarbon retaining system; routing exhaust gases to store exhaust hydrocarbons up to the increased temperature threshold; and initiating the selective purging at the increased temperature threshold.
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Specification