Methods and systems for EGR control

摘要

Methods and systems are provided for using compressor recirculation flow via a venturi to enhance low pressure EGR flow. The opening of a compressor recirculation valve can be adjusted based on EGR flow demand to recirculate cooled compressed air through a venturi while generating vacuum for drawing EGR. The approach allows for concurrent EGR control and surge control.

主权项

1. An engine method, comprising:
adjusting an amount of compressor recirculation flow delivered from downstream of a charge air cooler to a compressor inlet via a venturi based on EGR demand; and in response to compressor surge, increasing compressor recirculation flow around the compressor through a second recirculation passage parallel to a first recirculation passage, while maintaining the adjusted amount of compressor recirculation flow, the second passage not including a venturi coupled to an EGR passage.