# US 8,739,530 B2 · Compressor flow control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,739,530 B2 - Document ID: US8739530B2 - Status: Granted - Kind: B2 - Application number: 13/293,642 - Filed: 2011-11-10 - Published: 2013-05-16 - Granted: 2014-06-03 - Earliest claimed: 2011-11-10 - Assignees: Ford Global Technologies, LLC - Applicants: Deborah M. Bjorge; Julia Helen Buckland - Inventors: Deborah M. Bjorge; Julia Helen Buckland - Web page: https://patentgrep.com/patent/US8739530B2 ## CPC - F02B 37/001: {using exhaust drives arranged in parallel} - F02B 37/007: with exhaust-driven pumps arranged in parallel {, e.g. at least one pump supplying alternatively} - F02B 37/16: by bypassing charging air - F02B 37/162: {by bypassing, e.g. partially, intake air from pump inlet to pump outlet} - F02B 37/18: by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere} - F02D 23/00: Controlling engines characterised by their being supercharged - F02B 2037/125: {Control for avoiding pump stall or surge} - Y02T 10/12: Improving ICE efficiencies - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An engine system is provided. The system comprises an engine, first and second compressors supplying air to the engine, a first compressor recirculation valve adjustable to two restriction levels, and a second compressor recirculation valve adjustable to three or more restriction levels. In this way, the first and second compressor recirculation valves may be controlled to avoid compressor surge while providing a sufficient amount of boost to meet power demands. ## Claims ### Claim 1 A method for a turbocharger system having a first and second compressor, comprising: under a first condition, opening a first compressor recirculation valve (CRV) of the first compressor; under a second condition, opening the first CRV and adjusting a restriction amount of a second CRV of the second compressor; and under a third condition, closing the first CRV and adjusting the restriction amount of the second CRV, the second condition including a difference between mass-flow through a throttle and mass-flow at a surge line being greater than a mass-flow through the first CRV. ### Claim 2 (depends on 1) The method of claim 1, wherein the first condition includes a difference between mass-flow through the throttle and mass-flow at the surge line being equal to the mass-flow through the first CRV. ### Claim 3 (depends on 1) The method of claim 1, wherein the third condition includes a difference between mass-flow through the throttle and mass-flow at the surge line being less than the mass-flow through the first CRV. ### Claim 4 (depends on 3) The method of claim 3, wherein the mass-flow at the surge line is determined based on a pressure ratio-mass flow map stored in a control system. ### Claim 5 (depends on 1) The method of claim 1, wherein under the second and third conditions, the restriction amount of the second CRV is adjusted to increase a mass-flow rate across the second compressor. ### Claim 6 A method for a turbocharged engine with a first and second compressor, comprising: under high engine load, opening a first compressor recirculation valve of the first compressor and adjusting a second compressor recirculation valve of the second compressor based on a pressure ratio and mass-flow rate of the second compressor; and under low to medium engine load, adjusting the second compressor recirculation valve of the second compressor based on the pressure ratio and mass-flow rate of the second compressor. ### Claim 7 (depends on 6) The method of claim 6, further comprising under low to medium engine load, closing the first compressor recirculation valve. ### Claim 8 (depends on 6) The method of claim 6, wherein the first compressor recirculation valve includes two restriction levels and wherein the second compressor recirculation valve includes at least three restriction levels. ### Claim 9 (depends on 8) The method of claim 8, wherein under low to medium and high engine loads, adjusting the second compressor recirculation valve based on the pressure ratio and mass-flow rate of the second compressor further comprises decreasing a restriction amount of the second compressor recirculation valve to maintain mass-flow through the second compressor at a rate greater than a mass-flow rate at a surge line. ### Claim 10 (depends on 9) The method of claim 9, wherein the mass-flow rate at the surge line is dependent on the pressure ratio of the second compressor. ### Claim 11 (depends on 9) The method of claim 9, wherein the mass-flow at the surge line is determined based on a pressure ratio-mass flow map stored in a control system. ### Claim 12 An engine system, comprising: an engine; first and second compressors supplying air to the engine; a first compressor recirculation valve adjustable to two restriction levels; a second compressor recirculation valve adjustable to three or more restriction levels; and a controller including instructions for operating the first and second compressor recirculation valves concurrently when a difference between mass-flow through a throttle upstream of the engine and mass-flow at a surge line is above a second threshold. ### Claim 13 (depends on 12) The engine system of claim 12, the controller further including instructions for operating the second compressor recirculation valve while not operating the first compressor recirculation valve. ### Claim 14 (depends on 13) The engine system of claim 13, wherein the controller includes instructions for operating the second compressor recirculation valve while not operating the first compressor recirculation valve when a difference between mass-flow through the throttle upstream of the engine and mass-flow at the surge line is above a first threshold but below the second threshold. ### Claim 15 (depends on 14) The engine system of claim 14, wherein operating the second compressor recirculation valve comprises adjusting a restriction level of the second compressor recirculation valve based on the difference between mass-flow through the throttle and mass-flow at the surge line. ### Claim 16 (depends on 12) The engine system of claim 12, wherein the second threshold is equal to a mass-flow through the first compressor recirculation valve, and wherein the controller includes instructions for operating the first compressor recirculation valve while not operating the second compressor recirculation valve when the difference between mass-flow through the throttle and mass-flow at the surge line is equal to the second threshold. ### Claim 17 (depends on 12) The engine system of claim 12, wherein operating the second compressor recirculation valve comprises adjusting a restriction level of the second compressor recirculation valve based on the difference between mass-flow through the throttle and mass-flow at the surge line and further based on mass-flow through the first compressor recirculation valve when the first compressor recirculation valve is open.