System and method for controlling canister purging
First Claim
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1. A method for a boosted engine, comprising:
- during boosted conditions,flowing stored fuel vapors from a canister into an ejector coupled in a compressor bypass passage, the flowing bypassing a canister purge valve; and
responsive to a canister load higher than a threshold load,closing a canister vent valve coupled to the canister; and
discontinuing flowing stored fuel vapors from the canister into the ejector.
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Abstract
Methods and systems are provided for controlling canister purge flow in a boosted engine. An example method for the boosted engine comprises, during boosted conditions, flowing stored fuel vapors from a canister into an ejector coupled in a compressor bypass passage, the flowing bypassing a canister purge valve. The method further comprises, responsive to a canister load higher than a threshold load, closing a canister vent valve coupled to the canister, and discontinuing flowing stored fuel vapors from the canister into the ejector.
13 Citations
20 Claims
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1. A method for a boosted engine, comprising:
during boosted conditions, flowing stored fuel vapors from a canister into an ejector coupled in a compressor bypass passage, the flowing bypassing a canister purge valve; and responsive to a canister load higher than a threshold load, closing a canister vent valve coupled to the canister; and discontinuing flowing stored fuel vapors from the canister into the ejector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for a boosted engine, comprising:
during boosted conditions, maintaining open a canister vent valve; flowing stored fuel vapors from a canister of an evaporative emissions system into an ejector coupled in a compressor bypass passage; and adjusting the canister vent valve to a fully closed position in response to one of a canister load higher than a threshold load and a leak test of the evaporative emissions system. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A system, comprising:
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an engine; an intake manifold; an intake throttle; a boost device including a compressor, the compressor positioned in an intake passage upstream of the intake throttle; a canister purge valve comprising a solenoid valve and a sonic choke, the sonic choke coupled immediately downstream of the solenoid valve; an inlet of the sonic choke fluidically coupled to an outlet of the solenoid valve; an outlet of the sonic choke fluidically coupled to the intake manifold downstream of the intake throttle; an ejector coupled in a compressor bypass passage, the compressor bypass passage not including a shut-off valve; a motive inlet of the ejector coupled to the intake passage downstream of the compressor; a motive outlet of the ejector coupled to the intake passage upstream of the compressor; an evaporative emissions system including a fuel vapor canister, the fuel vapor canister fluidically communicating with each of an inlet of the canister purge valve and a suction port of the ejector; a canister vent valve fluidically coupling the fuel vapor canister to atmosphere; and a controller with instructions in non-transitory memory and executable by a processor for; during boosted conditions when pressure in the intake manifold is higher than barometric pressure, generating vacuum at the suction port of the ejector via motive flow; drawing fresh air into the fuel vapor canister via the canister vent valve; purging fuel vapors from the fuel vapor canister into the suction port of the ejector; and responsive to each of deceleration conditions and a load of the fuel vapor canister being higher than a threshold load; closing the canister vent valve to cease drawing fresh air into the fuel vapor canister; and discontinuing purging fuel vapors from the fuel vapor canister into the suction port of the ejector. - View Dependent Claims (19, 20)
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Specification