# US 2013/0158834 A1 · Method and device for ascertaining a modeling value for a physical variable in an engine system having an internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0158834 A1 - Document ID: US20130158834A1 - Status: Published application - Kind: A1 - Application number: 13/710,864 - Filed: 2012-12-11 - Published: 2013-06-20 - Earliest claimed: 2011-12-15 - Assignees: Robert Bosch GmbH - Inventors: Alexandre WAGNER; Thomas BLEILE; Slobodanka LUX; Christian FLECK - Web page: https://patentgrep.com/patent/US20130158834A1 ## CPC - F02D 41/263: {the program execution being modifiable by physical parameters} - F02D 41/0062: {Estimating, calculating or determining the internal EGR rate, amount or flow} - F02D 41/145: {with determination means using an estimation} - F02D 41/1446: {the characteristics being exhaust temperatures} - F02M 26/05: High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor - 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 26/25: with coolers having bypasses - Y02T 10/40: Engine management systems - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method for determining a modeling value of a physical variable in a gas guiding section of an engine system including an internal combustion engine, includes the following steps: operating the engine system in such a way that an air mass flow is present in the gas guiding section; determining instantaneous values of other physical variables; and determining the modeling value of the physical variable by solving a differential equation, which results as the discretization of a differential equation, with the aid of the previously ascertained instantaneous values of the other physical variables. ## Claims ### Claim 1 A method for determining a modeling value of a physical variable in a gas guiding section of an engine system including an internal combustion engine, the method comprising: operating the engine system such that an air mass flow is present in the gas guiding section; determining instantaneous values of other physical variables; and determining the modeling value of the physical variable by solving a differential equation, which results as a discretization of a differential equation, with the aid of the previously ascertained instantaneous values of the other physical variables. ### Claim 2 (depends on 1) The method according to claim 1, wherein the differential equation is formed based on an equation system employing at least one of a throttle model, ideal gas equation and law of conservation of mass. ### Claim 3 (depends on 1) The method according to claim 1, wherein the physical variable corresponds to at least one of a pressure and a gas mass flow at a branching point for an exhaust gas recirculation line downstream from a turbine of an exhaust-gas-driven turbocharger. ### Claim 4 (depends on 1) The method according to claim 1, wherein the other physical variables include a position of an exhaust gas recirculation valve, which is situated in a low-pressure-side exhaust gas recirculation line, a position of an exhaust gas valve, which is situated downstream from a branching point for the exhaust gas recirculation line, ambient pressure, an exhaust gas flow flowing to the branching point, a temperature of the exhaust gas at the branching point, and a pressure at an intake point of the exhaust gas recirculation line upstream from a compressor of an exhaust-gas-driven turbocharger. ### Claim 5 (depends on 1) The method according to claim 1, wherein the discretization of the differential equation is carried out according to an implicit method. ### Claim 6 (depends on 1) The method according to claim 1, wherein the modeling value of the physical variable is used in one of an exhaust gas recirculation rate regulation and an air flow regulation. ### Claim 7 (depends on 1) The method according to claim 1, wherein the differential equation is solved by an iterative method to determine the physical variable. ### Claim 8 (depends on 7) The method according to claim 7, wherein the iterative method is carried out between a first limiting value and a second limiting value for the physical variable. ### Claim 9 (depends on 8) The method according to claim 8, wherein the other physical variables include a first pressure in a first volume and a second pressure in a second volume of the gas guiding section, the first volume and the second volume being separated from one another by a flow resistance, the first limiting value for the physical variable being determined in that the first pressure is set equal to the second pressure, and the second limiting value for the physical variable being determined in that the second pressure is set equal to the first pressure. ### Claim 10 (depends on 1) The method according to claim 1, wherein the modeling value of the physical variable is determined for a plausibility check of the physical variable. ### Claim 11 A device for determining a modeling value of a physical variable in a gas guiding section of an engine system having an internal combustion engine, the device being configured to: operate the engine system such that an air mass flow is present in the gas guiding section; determine instantaneous values of other physical variables; and determine the modeling value of the physical variable by solving a differential equation, which results as a discretization of a differential equation, with the aid of the previously ascertained instantaneous values of the other physical variables. ### Claim 12 (depends on 11) An engine system, comprising: an internal combustion engine, to which air is supplied via an air supply section and from which combustion exhaust gas is discharged via an exhaust gas discharge section, wherein an exhaust gas recirculation line connects a branching point, which is provided downstream from an exhaust-gas-driven turbocharger, to an intake point situated upstream from the exhaust-gas-driven turbocharger in the air supply section; and the device according to claim 11 configured to ascertain a value of the physical variable existing at the branching point. ### Claim 13 (depends on 1, 11) A non-transitory computer-readable medium having stored thereon program code, which when executed on the device according to claim 11, performs all steps of the method according to claim 1.