Systems and methods for fuel vapor canister purge
First Claim
1. A method comprising:
- regulating purging of vapors stored in a storage canister into an engine intake with a first valve coupled to the intake and a second valve coupled to the canister, by transitioning between;
under first conditions during the purging, regulating flow through the first valve, and not through the second valve; and
under second, different, conditions during the purging, regulating flow through the second valve, and not through the first valve.
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Accused Products
Abstract
Methods and systems are provided for controlling the purging of a fuel vapor canister coupled to a vehicle fuel tank, configured for capturing and storing vapors emanating from the tank. In one example, two canister purge valves are coupled in series in a fuel vapor conduit between the fuel vapor canister and engine intake, one at the intake manifold and one at the fuel vapor canister, such that fine control over the introduction of fuel vapors into the engine is maintained via the purge valve at the intake manifold, while thorough purging of the fuel vapor canister may be regulated via the purge valve at the fuel vapor canister. In this way, fuel vapors in the fuel vapor canister may be effectively purged to intake, thus reducing the potential for undesired evaporative emissions.
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Citations
20 Claims
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1. A method comprising:
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regulating purging of vapors stored in a storage canister into an engine intake with a first valve coupled to the intake and a second valve coupled to the canister, by transitioning between; under first conditions during the purging, regulating flow through the first valve, and not through the second valve; and under second, different, conditions during the purging, regulating flow through the second valve, and not through the first valve. - View Dependent Claims (2, 3, 4)
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5. A method for a vehicle comprising:
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purging fuel vapors stored in a fuel vapor canister to an intake manifold of an engine; during a canister purging with a canister vent valve open, duty cycling a first canister purge valve and commanding open a second canister purge valve; and stopping duty cycling the first canister purge valve, opening the first canister purge valve, and commencing duty cycling the second canister purge valve responsive to a canister load below a threshold canister load. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A system for a vehicle comprising:
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a fuel tank configured within a fuel system; a fuel vapor canister configured within an evaporative emissions system, and coupled to the fuel tank that provides fuel to an internal combustion engine; an intake manifold of the internal combustion engine, coupled to the fuel vapor canister via a first canister purge valve and a second canister purge valve; a canister vent valve, positioned between the fuel vapor canister and atmosphere; and a controller storing instructions in non-transitory memory, that when executed, cause the controller to; purge stored fuel vapors to the intake manifold of the engine for combustion by coupling the fuel vapor canister to atmosphere via the canister vent valve by commanding open the canister vent valve, and applying engine intake manifold vacuum to the fuel vapor canister by opening one or more of the canister purge valves to draw fresh air across the fuel vapor canister to desorb fuel vapors; in a first condition during purging, purging stored fuel vapors to the intake manifold of the engine by applying a first pressure drop between the intake manifold and the fuel vapor canister; in a second condition during purging, purging stored fuel vapors to the intake manifold of the engine by applying a second pressure drop between the intake manifold and the fuel vapor canister; wherein the first pressure drop is greater than the second pressure drop; wherein the first condition includes duty cycling the first canister purge valve and commanding open the second canister purge valve; wherein the second condition includes opening the first canister purge valve and duty cycling the second canister purge valve; and wherein the first and second canister purge valves are arranged in series. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification