Method of controlling aspirator motive flow

A system for an engine, comprising:

• an engine intake manifold;
• an intake throttle coupled in an intake passage;
• an aspirator coupled in a bypass air intake passage across the intake throttle;
• an aspirator control valve, positioned downstream of the aspirator in the bypass air intake passage, regulating motive flow through each of the aspirator and the bypass air intake passage;
• a motive inlet of the aspirator coupled to the intake passage upstream of the intake throttle;
• a motive outlet of the aspirator coupled to the intake passage downstream of the intake throttle;
• and
• a controller with instructions in non-transitory memory and executable by a processor for:
• responsive to an indication of a first engine degradation condition,
• closing the aspirator control valve;
• and
• discontinuing generation of vacuum via the aspirator,
• wherein the first engine degradation condition includes an increase in intake manifold vacuum level above a first threshold level, and
• wherein the first engine degradation condition includes degradation of a variable valve timing system.

A method for an engine, comprising:

• closing an aspirator control valve (ACV) responsive to diagnosing a first engine degradation condition;
• opening the ACV in response to diagnosing a second engine degradation condition, the second engine degradation condition being distinct from the first engine degradation condition;
• wherein the first engine degradation condition includes an increase in intake manifold vacuum level above a first threshold level;
• wherein the first engine degradation condition includes degradation of a mass air flow (MAF) sensor;
• and
• discontinuing flow of exhaust gas recirculation (EGR) responsive to the degradation of the MAF sensor.