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Methods and systems are provided for coordinating adjustments to a compressor recirculation valve with adjustments to a binary flow turbine scroll valve to reduce surge. The scroll valve is closed to increase turbine energy while the compressor recirculation valve is opened to increase compressor fl

Methods and systems are provided for coordinating adjustments to a compressor recirculation valve with adjustments to a binary flow turbine scroll valve to reduce surge. The scroll valve is closed to increase turbine energy while the compressor recirculation valve is opened to increase compressor flow. Concurrent adjustments to a wastegate may be used to provide boost pressure control.

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1. A method for controlling a boosted engine, comprising: in response to an indication of surge from one or more sensors, adjusting compressor flow by adjusting, via a controller, each of a first actuator of a first valve located in a passage coupling a compressor outlet to a compressor inlet, and a

1. A method for controlling a boosted engine, comprising: in response to an indication of surge from one or more sensors, adjusting compressor flow by adjusting, via a controller, each of a first actuator of a first valve located in a passage coupling a compressor outlet to a compressor inlet, and a second actuator of a second valve coupled to an outer, secondary scroll of a multi-scroll exhaust turbine. 2. The method of claim 1, wherein the adjusting of the first valve is based on the indication of surge, and wherein the adjusting of the second valve is based on the adjusting of the first valve. 3. The method of claim 2, wherein the adjusting of the first valve includes increasing an opening of the first valve as the indication of surge increases. 4. The method of claim 3, wherein the first valve is a continuously variable valve whose position is continuously variable between a fully-open position and a fully-closed position, and wherein the passage couples the compressor outlet downstream of a charge air cooler to the compressor inlet. 5. The method of claim 4, wherein the adjusting of the second valve includes closing the second valve, a timing and/or degree of the closing based on the increasing an opening of the first valve. 6. The method of claim 5, wherein increasing an opening of the first valve includes increasing the opening to increase recirculation of compressed air from the compressor outlet to the compressor inlet, and wherein closing the second valve includes closing the second valve to disable flow of exhaust gas to the outer, secondary scroll of the turbine. 7. The method of claim 6, further comprising adjusting a wastegate coupled across the turbine based on each of the adjusting of the first valve and the adjusting of the second valve to maintain a desired engine boost pressure. 8. The method of claim 7, wherein adjusting the wastegate includes reducing an opening of the wastegate in response to the increasing an opening of the first valve and the closing of the second valve. 9. The method of claim 8, wherein the adjusting of the wastegate is further based on one or more of engine boost pressure, a turbine inlet temperature, a turbine inlet pressure, and an engine air demand. 10. A method for controlling an engine, comprising: in response to surge indicated by one or more sensors,adjusting a first actuator via a controller to adjust a first valve to increase recirculation of compressed air to a compressor inlet;adjusting a second actuator via the controller to adjust a second valve coupled to an outer scroll of a multi-scroll turbine based on the adjusting of the first valve; andadjusting a third actuator via the controller to adjust a wastegate coupled across the turbine based on the adjustments to each of the first and second valves. 11. The method of claim 10, wherein adjusting the first valve to increase recirculation of compressed air to a compressor inlet includes increasing an opening of the first valve to increase recirculation of cooled compressed air from downstream of the compressor and downstream of a charge air cooler to the compressor inlet. 12. The method of claim 10, wherein adjusting the first valve includes increasing an opening of the first valve based on an indication of the surge to increase a compressor flow rate. 13. The method of claim 12, wherein increasing an opening of the first valve includes shifting the first valve from a first, semi-open position to a second, fully-open position. 14. The method of claim 12, wherein adjusting the second valve includes decreasing an opening of the second valve based on the increasing of the opening of the first valve to increase a turbine inlet pressure. 15. The method of claim 14, wherein adjusting the wastegate includes adjusting the wastegate based on the adjustments to each of the first and second valves to maintain a desired boost pressure. 16. The method of claim 14, wherein the turbine further includes an inner scroll, the second valve not coupled to the inner scroll, and wherein decreasing an opening of the second valve includes fully closing the second valve to limit flow of exhaust gas through the outer scroll while enabling flow of exhaust gas through the inner scroll. 17. An engine system, comprising: an engine;a turbocharger including a compressor driven by a multi-scroll turbine;a charge air cooler located downstream of the compressor for cooling a boosted aircharge delivered to the engine;a compressor recirculation passage including a first valve coupling an outlet of the charge air cooler to an inlet of the compressor;a wastegate coupling a turbine outlet to a turbine inlet;a second valve coupled to an inlet of an outer scroll of the turbine; anda controller with computer readable instructions for: operating the engine boosted with the first valve partially open and the second valve fully open; andin response to an indication of surge, increasing an opening of the first valve based on the indication and decreasing an opening of the second valve based on the opening of the first valve. 18. The system of claim 17, wherein decreasing an opening of the second valve based on the opening of the first valve includes estimating a turbine power required to enable compressor recirculation flow at the opening of the first valve, and decreasing an opening of the second valve to provide a turbine inlet pressure that provides the estimated turbine power. 19. The system of claim 17, wherein the controller includes further instructions for, while increasing the opening of the first valve and decreasing the opening of the second valve, adjusting a position of the wastegate based on adjustments to each of the first and second valves to maintain a turbine inlet pressure. 20. The system of claim 19, wherein the adjusting includes decreasing an opening of the wastegate as the opening of the first valve is increased and the opening of the second valve is decreased.