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US 9,309,837 B2Granted
Methods and systems for EGR control
AssigneeFord Global Technologies, LLC
InventorsJoseph Norman Ulrey, Gregory Patrick McConville, Daniel Joseph Styles, Ross Dykstra Pursifull, Michael Howard Shelby
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Abstract
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.
Claims20
A method for an engine, comprising:
- recirculating an amount of compressed air from downstream of a charge air cooler to a compressor inlet through a first compressor recirculation passage via a venturi based on EGR flow demand while recirculating another amount to the compressor inlet through a second compressor recirculation passage not including a venturi based on a surge margin;
- and
- using vacuum generated at the venturi to draw EGR into the compressor inlet.
A method for an engine, comprising,
- adjusting an opening of a first valve based on a surge limit and a water content of low-pressure exhaust gas recirculation (EGR) to draw compressor recirculation flow from downstream of a charge air cooler to a compressor inlet via a venturi;
- and
- adjusting an opening of a second valve based on vacuum drawn at the venturi to draw the EGR into the compressor inlet via an EGR passage coupled to the compressor recirculation passage at the venturi.
An engine system, comprising:
- an engine including an intake and an exhaust;
- a turbocharger including an exhaust turbine driven by an intake compressor;
- a charge air cooler coupled downstream of the compressor;
- a first compressor recirculation passage including a first valve and a venturi, the first passage coupling an outlet of the charge air cooler to an inlet of the compressor, the venturi positioned downstream of the first valve in the first passage;
- a second compressor recirculation passage including a second valve, the second passage parallel to the first passage and coupling the outlet of the charge air cooler to the inlet of the compressor;
- an EGR passage including an EGR valve for recirculating exhaust residuals to the first compressor recirculation passage, downstream of the venturi;
- and
- a controller with computer readable instructions for,
- adjusting an opening of the first valve based on an exhaust pressure upstream of an inlet of the EGR passage to generate venturi vacuum to provide a desired EGR flow;
- and
- adjusting an opening of the second valve based on a margin to compressor surge with the first valve open.
8 more elements
Dependencies are inferred from the claim text.