PARALLEL ASPIRATOR ARRANGEMENT FOR VACUUM GENERATION AND COMPRESSOR BYPASS

摘要

Methods and systems are provided for a parallel arrangement of at least two aspirators bypassing an intake compressor in an engine system, the aspirator arrangement including an aspirator shut-off valve arranged in series with each aspirator. The aspirator shut-off valves may be controlled based on engine vacuum needs as well as based on intake manifold pressure, during non-boost conditions, and compressor surge, during boost conditions. For example, during boost conditions, the aspirator shut-off valves may be controlled to enable a selectable discrete compressor recirculation flow rate, whereas during non-boost conditions the aspirator shut-off valves may be controlled to enable a selectable, discrete level of vacuum generation for use by various engine vacuum consumers.