# US 2014/0196697 A1 · Internal Combustion Engine Having Dedicated EGR Cylinder(s) With Intake Separate From Intake Of Main Cylinders > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0196697 A1 - Document ID: US20140196697A1 - Status: Published application - Kind: A1 - Application number: 13/741,955 - Filed: 2013-01-15 - Published: 2014-07-17 - Earliest claimed: 2013-01-15 - Assignees: Southwest Research Institute - Applicants: Southwest Research Institute - Inventors: Robert W. Burrahm - Web page: https://patentgrep.com/patent/US20140196697A1 ## CPC - F02M 26/15: in relation to engine exhaust purifying apparatus - F02M 26/35: with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters - F02M 26/43: in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine - F02M 26/04: with a single turbocharger - Y02T 10/12: Improving ICE efficiencies - 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 using an internal combustion engine with dedicated EGR cylinders to provide an adjustable EGR rate to the main (non dedicated) cylinders. The dedicated EGR cylinder(s) are configured to receive fresh air via a fresh air intake or to receive a portion of the mixture of fresh air and EGR gas via the same mixed intake line that delivers intake to the main cylinders. If the dedicated EGR cylinder(s) receive only fresh air, the main cylinder(s) receive EGR at higher EGR rate. If the dedicated EGR cylinder(s) receive only the portion of fresh air and EGR gas, the main cylinder(s) receive EGR at a lower EGR rate. The EGR rate to the main cylinder(s) may be adjusted between these rates in response to operating conditions of the engine. ## Claims ### Claim 1 A method of using exhaust gas recirculation (EGR) to improve combustion efficiency of an internal combustion engine having a number of cylinders, comprising: operating one or more of the cylinders as dedicated EGR cylinder(s), such that all of its exhaust, during all or some engine cycles, may be recirculated via an EGR loop as EGR gas; operating all non dedicated EGR cylinder(s) as main cylinders that receive a mixture of fresh air and EGR gas via a mixed intake line; wherein the dedicated EGR cylinder(s) are configured to receive only fresh air via a separate fresh air intake to the EGR cylinder or to receive a portion of the EGR gas and fresh air; wherein if the dedicated EGR cylinder(s) receive only fresh air, the main cylinder(s) receive EGR at a first EGR rate; wherein if the dedicated EGR cylinder(s) receive only the portion of EGR gas and fresh air, the main cylinder(s) receive EGR at a second EGR rate; and adjusting the rate of EGR gas received by the main cylinder(s) to the first EGR rate or to the second EGR rate in response to operating conditions of the engine. ### Claim 2 (depends on 1) The method of claim 1, wherein the dedicated EGR cylinder(s) has a single exhaust port that may open to the EGR loop. ### Claim 3 (depends on 1) The method of claim 1, wherein the dedicated EGR cylinder(s) has dual exhaust ports, one of which may open to the EGR loop and the other of which may open to the engine's main exhaust line. ### Claim 4 (depends on 1) The method of claim 1, wherein the engine's non dedicated EGR cylinder(s) are run stoichiometrically. ### Claim 5 (depends on 1) The method of claim 1, wherein the engine's non dedicated EGR cylinder(s) are run rich. ### Claim 6 (depends on 1) The method of claim 1, wherein the engine's non dedicated EGR cylinder(s) are run lean. ### Claim 7 (depends on 1) The method of claim 1, wherein the portion of EGR gas and fresh air is delivered to the dedicated EGR cylinder( ) via a passage downstream of a mixer in the intake to the main cylinders. ### Claim 8 (depends on 1) The method of claim 1, wherein the portion of EGR gas and fresh air is delivered to the dedicated EGR cylinder(s) via a passage from the EGR loop to the separate fresh air intake. ### Claim 9 (depends on 1) The method of claim 1, further comprising adjusting the EGR rate to the main cylinders to a rate between the first EGR rate and the second EGR rate. ### Claim 10 (depends on 9) The method of claim 9, wherein the adjusting is performed by adjusting the relative amount of fresh air and portion of the mixture of fresh air and EGR received by the dedicated EGR cylinder(s). ### Claim 11 An exhaust gas recirculation (EGR) system for improved combustion efficiency of an internal combustion engine having a number of cylinders, comprising: one or more cylinders operable as dedicated EGR cylinder(s), such that all of its exhaust, during all or some engine cycles, may be recirculated via an EGR loop; one or more cylinders operable as main cylinders that receive EGR via the EGR loop and receive fresh air via a second fresh air intake line; an EGR loop for recirculating EGR from the dedicated EGR cylinder(s) to the engine's intake manifold; a mixed input line for delivering a mixture of fresh air and EGR gas to the intake of the main cylinders; a passage between the mixed input line and the intake line to the dedicated EGR cylinder, operable to deliver a portion of the mixture of fresh air and EGR to the dedicated EGR cylinder(s); wherein the dedicated EGR cylinder(s) may receive an intake comprising all fresh air or all the mixture or some proportion of both; a control unit programmed to perform the following tasks: receive data representing engine operating conditions, determine a desired EGR rate of EGR to be delivered to the main cylinders, and based on the desired EGR air, to control whether the dedicated EGR cylinder(s) receive all fresh air or all the mixture or some proportion of both. ### Claim 12 (depends on 11) The system of claim 11, wherein the dedicated EGR cylinder(s) has a single exhaust port that may open to the EGR loop. ### Claim 13 (depends on 11) The system of claim 11, wherein the dedicated EGR cylinder(s) has dual exhaust ports, one of which may open to the EGR loop and the other of which may open to the engine's main exhaust line. ### Claim 14 (depends on 11) The system of claim 11, wherein the engine's non dedicated EGR cylinder(s) are run stoichiometrically. ### Claim 15 (depends on 11) The system of claim 11, wherein the engine's non dedicated EGR cylinder(s) are run lean. ### Claim 16 (depends on 11) The system of claim 11, wherein the engine's non dedicated EGR cylinder(s) are run rich. ### Claim 17 (depends on 11) The system of claim 11, further comprising an first valve on the passage line and a second valve on the fresh air line. ### Claim 18 (depends on 17) The system of claim 17, wherein the control unit is further programmed to control the first valve and the second valve such that the dedicated EGR cylinder(s) may receive proportions of fresh air and the mixture, and to adjust the proportions based on engine operating conditions.