# US 8,769,927 B2 · EGR control in engine equipped with cylinders having dual exhaust valves > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,769,927 B2 - Document ID: US8769927B2 - Status: Granted - Kind: B2 - Application number: 13/614,966 - Filed: 2012-09-13 - Published: 2014-03-13 - Granted: 2014-07-08 - Earliest claimed: 2012-09-13 - Assignees: Southwest Research Institute - Applicants: Terrence F. Alger, II; Jess W. Gingrich - Inventors: Terrence F. Alger, II; Jess W. Gingrich - Web page: https://patentgrep.com/patent/US8769927B2 ## CPC - F02B 47/08: the substances including exhaust gas - F02M 26/43: in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine - 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 A method and system for controlling recirculated exhaust gas composition and quantity provided to an internal combustion engine, which has one or more separately controllable combustion cylinders, a main exhaust line and an exhaust gas recirculation (EGR) loop. A first exhaust valve is connected to the main exhaust line, and a second exhaust valve is connected to the EGR loop. The operation of the exhaust valves is controlled such that exhaust does not flow through both exhaust valves at the same time. Control of the exhaust valves is coordinated with the main fueling event used to control the exhaust composition exiting each valve for every cylinder on every cycle. During each engine cycle, a post-combustion fuel injection event is also used to add fuel to the exhaust in-cylinder, which flows only through the second (EGR) exhaust valve. ## Claims ### Claim 1 A method of controlling recirculated exhaust gas provided to an internal combustion engine, which has one or more combustion cylinders, a main exhaust line and an exhaust gas recirculation (EGR) loop, comprising: providing each cylinder with two exhaust valves, each separately controllable; wherein a first exhaust valve is connected to the main exhaust line and a second exhaust valve is connected to the EGR loop; controlling the exhaust valves such that exhaust from each cylinder does not flow through both of its exhaust valves at the same time; providing a post-combustion fuel injection event during each engine cycle; and timing the post-combustion fuel injection event and the operation of the exhaust valves so that exhaust from the post-combustion fuel injection event flows only through the second exhaust valve. ### Claim 2 (depends on 1) The method of claim 1, further comprising routing the recirculated exhaust through a catalytic conversion unit on the EGR loop. ### Claim 3 (depends on 1) The method of claim 1, further comprising routing the recirculated exhaust through a water gas shift catalyst on the EGR loop. ### Claim 4 (depends on 1) The method of claim 1, further comprising controlling the ratio of exhaust that flows from the first exhaust valve into the main exhaust line versus the exhaust that flows from the second exhaust valve into the EGR loop. ### Claim 5 (depends on 4) The method of claim 4, wherein the controlling is performed by controlling the exhaust valve events (phasing, lift and/or duration) of the second exhaust valve, resulting in more or less mass flow from each cylinder's EGR port. ### Claim 6 (depends on 1) The method of claim 1, wherein the two exhaust valves of each cylinder have the same size ports. ### Claim 7 (depends on 1) The method of claim 1, wherein the two exhaust valves of each cylinder have differently sized ports. ### Claim 8 (depends on 1) The method of claim 1, further comprising controlling operating one or more cylinders rich and exhausting its exhaust entirely from its second exhaust valve. ### Claim 9 (depends on 1) The method of claim 1, wherein the one or more cylinder is operated rich and exhausted through its second exhaust valve on a cycle-by-cycle basis. ### Claim 10 A recirculated exhaust gas system for an internal combustion engine, which has one or more combustion cylinders, each having a pair of separately controllable exhaust valves and a main exhaust line connected to a first one of each pair of exhaust valves, comprising: an exhaust gas recirculation (EGR) loop connected to a second one of each pair of exhaust valves; a control unit programmed to control the exhaust valves such that exhaust from each cylinder does not flow through both of its exhaust valves at the same time, and to activate a post-combustion fuel injection event during each engine cycle; wherein the post-combustion fuel injection event and the operation of the exhaust valves are timed so that exhaust from the post-combustion fuel injection event flows only through the second exhaust valve. ### Claim 11 (depends on 10) The system of claim 10, wherein the EGR loop has an oxidation catalyst. ### Claim 12 (depends on 10) The system of claim 10, wherein the EGR loop has a water gas shift catalyst. ### Claim 13 (depends on 10) The system of claim 10, wherein the control unit is further programmed to control the ratio of exhaust that flows from the first exhaust valve into the main exhaust line versus the exhaust that flows from the second exhaust valve into the EGR loop. ### Claim 14 (depends on 13) The system of claim 13, wherein the controlling is performed by controlling the exhaust valve events (phasing, lift and/or duration) of the second exhaust valve, resulting in more or less mass flow from each cylinder's EGR port. ### Claim 15 (depends on 10) The system of claim 10, wherein the two exhaust valves of each cylinder have the same size ports. ### Claim 16 (depends on 10) The system of claim 10, wherein the two exhaust valves of each cylinder have differently sized ports. ### Claim 17 (depends on 10) The system of claim 10, wherein the control unit is further programmed to operate one or more cylinders rich and exhausting its exhaust entirely from its second exhaust valve. ### Claim 18 (depends on 10) The system of claim 10, wherein the one or more cylinder is operated rich and exhausted through its second exhaust valve on a cycle-by-cycle basis.