METHOD AND SYSTEM FOR FUEL VAPOR MANAGEMENT
First Claim
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1. A method for a boosted engine, comprising:
- during boosted conditions, drawing vacuum at a first aspirator using compressor bypass flow;
during non-boosted conditions, enhancing intake manifold vacuum by drawing vacuum at a second aspirator using intake throttle bypass flow; and
during both conditions, applying the drawn vacuum to purge fuel vapors from each of a canister and a crankcase to an intake manifold.
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Abstract
Methods and systems are provided for shared handling of fuel vapor purge and crankcase ventilation in an engine system. Fuel vapors from each of a canister and a crankcase are drawn into an intake manifold in a common direction during both boosted and non-boosted engine operating conditions using vacuum drawn at various aspirators. Compressor bypass flow through a first aspirator is used to enhance vacuum produced during boosted conditions while throttle bypass flow through a second aspirator is used to enhance vacuum produced during non-boosted conditions.
51 Citations
20 Claims
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1. A method for a boosted engine, comprising:
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during boosted conditions, drawing vacuum at a first aspirator using compressor bypass flow; during non-boosted conditions, enhancing intake manifold vacuum by drawing vacuum at a second aspirator using intake throttle bypass flow; and during both conditions, applying the drawn vacuum to purge fuel vapors from each of a canister and a crankcase to an intake manifold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for an engine, comprising:
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when operating the engine boosted, drawing fuel vapors in a first direction from each of a fuel system canister and a crankcase into an engine intake manifold using vacuum drawn at a first aspirator coupled to a compressor; and when operating the engine non-boosted, drawing fuel vapors from each of the canister and the crankcase in the first direction into the intake manifold using intake manifold vacuum. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An engine system, comprising:
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an engine including an intake manifold; a compressor for providing a boosted aircharge; a compressor bypass including a compressor bypass valve for diverting a first portion of intake air around the compressor; a first aspirator coupled to the compressor bypass; a throttle coupled in the intake manifold; a throttle bypass including a throttle bypass valve for diverting a second portion of intake air around the throttle; a second aspirator coupled to the throttle bypass; a crankcase coupled to the intake manifold; and a canister for storing fuel vapors generated in a fuel tank; and a controller with computer readable instructions for, operating the compressor to provide a boosted intake aircharge; while operating boosted, flowing the first portion of diverted intake air through the first aspirator, from an aspirator inlet to an aspirator outlet, and generating vacuum at a vacuum inlet of the first aspirator; applying the generated vacuum to draw fuel vapors in a first direction from the canister and the crankcase to upstream of the compressor; and combusting the drawn fuel vapors in the engine. - View Dependent Claims (20)
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Specification