# US 2014/0190160 A1 · Method and system for exhaust gas recirculation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190160 A1 - Document ID: US20140190160A1 - Status: Published application - Kind: A1 - Application number: 14/203,122 - Filed: 2014-03-10 - Published: 2014-07-10 - Earliest claimed: 2011-07-22 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Daniel Joseph Styles; Brad Alan Boyer; Satheesh Makkapati - Web page: https://patentgrep.com/patent/US20140190160A1 ## CPC - F02B 37/12: Control of the pumps - F02M 26/06: Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor - F02M 26/08: for engines having two or more intake charge compressors or exhaust gas turbines, e.g. a turbocharger combined with an additional compressor - F02M 26/10: having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system - F02M 26/33: controlling the temperature of the recirculated gases - F02M 26/38: with two or more EGR valves disposed in parallel - F02B 29/0406: {Layout of the intake air cooling or coolant circuit} - F02B 33/00: Engines characterised by provision of pumps for charging or scavenging - F02B 33/40: of non-positive-displacement type - F02B 33/446: {having valves for admission of atmospheric air to engine, e.g. at starting} - 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 37/013: with exhaust-driven pumps arranged in series - F02B 37/16: by bypassing charging air - F02B 37/18: by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere} - F02M 26/23: Layout, e.g. schematics - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Methods and systems are provided for an engine including a first turbocharger having a first compressor and a second turbocharger having a second compressor. An EGR differential between the first compressor and the second compressor may be increased under a condensation condition, and decreased under a surge condition. The EGR differential may also be decreased when a compressor outlet temperature exceeds an outlet temperature threshold. ## Claims ### Claim 1 A method of operating a twin-turbocharger engine, comprising: increasing an EGR flow differential between EGR flow to a first compressor and to a second compressor via a cross-over valve responsive to an intake temperature that corresponds with condensation accumulation; and decreasing the EGR flow differential between EGR flow to the first and to the second compressor via the cross-over valve responsive to a surge condition. ### Claim 2 (depends on 1) The method of claim 1, wherein the twin-turbocharger engine includes a first cylinder bank and a second cylinder bank. ### Claim 3 (depends on 1) The method of claim 1, wherein EGR flow differential is determined based on spark timing. ### Claim 4 (depends on 1) The method of claim 1, wherein EGR flow differential is determined based on air-fuel ratio. ### Claim 5 (depends on 1) The method of claim 1, wherein EGR flow differential is determined based on engine speed. ### Claim 6 (depends on 1) The method of claim 1, wherein increasing the EGR flow differential further comprises reducing exhaust gas flow to the second compressor. ### Claim 7 (depends on 1) The method of claim 1, wherein decreasing the EGR flow differential further comprises increasing exhaust gas flow to the second compressor. ### Claim 8 (depends on 1) The method of claim 1, further including: estimating a manifold pressure; estimating an air flow downstream from the first compressor; and if the manifold pressure exceeds a pressure threshold and the air flow is below an air flow threshold, then decreasing the EGR flow differential between EGR flow to the first and second compressors. ### Claim 9 (depends on 8) The method of claim 8, wherein if the manifold pressure is below the pressure threshold or the air flow exceeds the air flow threshold, then increasing the EGR flow differential between EGR flow to the first and second compressors. ### Claim 10 (depends on 1) The method of claim 1, further comprising: estimating a first compressor outlet temperature; and if the first compressor outlet temperature exceeds an outlet temperature threshold, then decreasing the EGR flow differential between EGR flow to the first and second compressors. ### Claim 11 (depends on 10) The method of claim 10, further comprising decreasing the EGR flow differential between the EGR flow to the first and second compressors only when the surge condition exists or the first compressor outlet temperature exceeds the outlet temperature threshold. ### Claim 12 (depends on 1) The method of claim 1, wherein EGR flow differential is determined based on a surge margin. ### Claim 13 (depends on 1) The method of claim 1, further comprising adjusting engine operating parameters to compensate for transient changes in the EGR flow differential. ### Claim 14 A method of operating a cross-over valve of an engine, comprising: opening the cross-over valve if a manifold pressure exceeds a pressure threshold and an air flow is below an air flow threshold, the cross-over valve positioned in a low-pressure EGR cross-over loop fluidically coupling EGR upstream of a first and a second engine turbocharger compressor; closing the cross-over valve if the manifold pressure is below the pressure threshold or the air flow exceeds the air flow threshold; and adjusting engine operating parameters to compensate for the opening and closing of the cross-over valve generating changes in an EGR flow differential between EGR flow to the first compressor and to the second compressor. ### Claim 15 (depends on 14) The method of claim 14, wherein opening the cross-over valve includes increasing exhaust gas flow through the cross-over loop. ### Claim 16 (depends on 14) The method of claim 14, wherein closing the cross-over valve includes decreasing exhaust gas flow through the cross-over loop. ### Claim 17 (depends on 14) The method of claim 14, further comprising: estimating a compressor outlet temperature; and if the compressor outlet temperature exceeds an outlet temperature threshold, then increasing exhaust gas flow through the cross-over loop by opening the cross-over valve. ### Claim 18 (depends on 17) The method of claim 17, further comprising opening the cross-over valve only when the manifold pressure exceeds the pressure threshold and the air flow is below the air flow threshold, or the compressor outlet temperature exceeds the outlet temperature threshold. ### Claim 19 (depends on 14) The method of claim 14, wherein closing the cross-over valve includes partially closing the cross-over valve to adjust an amount of exhaust gas delivered to the EGR cross-over loop. ### Claim 20 (depends on 14) The method of claim 14, wherein the EGR cross-over loop is fluidically coupled to an EGR loop, the EGR loop is fluidically coupled to a first intake passage upstream from a first compressor, and opening the cross-over valve includes delivering exhaust flow through the EGR cross-over loop to a second intake passage upstream of a second compressor.