# US 10,119,479 B2 · Methods and systems for boost control based on exhaust pressure greater than a threshold > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,119,479 B2 - Document ID: US10119479B2 - Status: Granted - Kind: B2 - Application number: 14/820,409 - Filed: 2015-08-06 - Published: 2017-02-09 - Granted: 2018-11-06 - Earliest claimed: 2015-08-06 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Philip Andrew Fabien; Stephen George Russ; Michael A. Mancini; Jonathan Cherry - Web page: https://patentgrep.com/patent/US10119479B2 ## CPC - F02D 9/02: concerning induction conduits (throttle valves, or arrangements thereof in conduits F02D9/08) - F02B 37/18: by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere} - F02B 37/183: {Arrangements of bypass valves or actuators therefor} - F02B 37/225: {air passages} - F02D 13/0261: {Controlling the valve overlap} - F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)} - F02D 41/145: {with determination means using an estimation} - F01N 3/021: by means of filters - F01N 11/002: {the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus} - F01N 2260/14: for modifying or adapting flow area or back-pressure - F01N 2560/06: the means being a temperature sensor - F01N 2560/07: the means being an exhaust gas flow rate or velocity meter or sensor, intake flow meters only when exclusively used to determine exhaust gas parameters - F01N 2560/08: the means being a pressure sensor - F01N 2900/1404: Exhaust gas temperature - F01N 2900/1406: Exhaust gas pressure - F01N 2900/1411: Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate - F02D 41/1448: {the characteristics being an exhaust gas pressure} - F02D 41/18: by measuring intake air flow - F02D 2009/0228: {Manifold pressure} - F02D 2041/001: {for engines with variable valve actuation} - F02D 2200/0406: Intake manifold pressure - F02D 2200/0414: Air temperature - F02D 2200/0812: Particle filter loading - F02D 2200/501: Vehicle speed - Y02T 10/12: Improving ICE efficiencies - 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) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Methods and systems are provided for mitigating excessive exhaust pressures in an engine. In one example, a method may include adjusting an intake throttle responsive to exhaust pressure upstream of an exhaust turbine being higher than a threshold without reducing boost level. In this way, boost pressures may be maintained while reducing exhaust pressures. ## Claims ### Claim 1 A method for an engine, comprising: adjusting an intake throttle responsive to pre-turbine exhaust pressure greater than a threshold without reducing boost level and while maintaining valve timing, wherein the threshold is based on a pressure required to force open a closed exhaust valve. ### Claim 2 (depends on 1) The method of claim 1, wherein the pre-turbine exhaust pressure is a predicted pressure. ### Claim 3 (depends on 2) The method of claim 2, wherein the pre-turbine exhaust pressure is modeled based on a post-turbine exhaust manifold pressure. ### Claim 4 (depends on 3) The method of claim 3, wherein the engine includes a soot filter coupled downstream of a turbocharger turbine, and wherein the pre-turbine exhaust pressure is further modeled based on soot load of the soot filter and the boost level. ### Claim 5 (depends on 4) The method of claim 4, wherein the pre-turbine exhaust pressure is further modeled based on one or more of engine air flow, exhaust flow, spark timing, air-fuel ratio, cam timing, manifold temperature, vehicle speed, and manifold pressure. ### Claim 6 (depends on 3) The method of claim 3, wherein the post-turbine exhaust manifold pressure is estimated by an exhaust pressure sensor. ### Claim 7 (depends on 1) The method of claim 1, wherein the adjusting includes reducing an opening of the intake throttle until the pre-turbine exhaust pressure is below the threshold. ### Claim 8 (depends on 7) The method of claim 7, wherein the adjusting includes reducing the opening of the intake throttle for a threshold duration, and responsive to the pre-turbine exhaust pressure remaining greater than the threshold after the threshold duration, reducing boost level by adjusting an exhaust wastegate. ### Claim 9 (depends on 8) The method of claim 8, wherein the adjusting further includes reducing the opening of the intake throttle while closing the exhaust wastegate. ### Claim 10 (depends on 8) The method of claim 8, wherein the engine is coupled in a vehicle and wherein the threshold duration includes one of a threshold number of engine combustion events, a threshold duration of vehicle travel, and a time taken for a threshold distance of vehicle travel. ### Claim 11 (depends on 10) The method of claim 10, wherein reducing the boost level by adjusting the exhaust wastegate includes increasing an opening of the exhaust wastegate to reduce the boost level until the pre-turbine exhaust pressure is lower than the threshold. ### Claim 12 A method for an engine, comprising: treating engine exhaust gas with a particulate filter, the particulate filter positioned downstream of a turbocharger turbine; estimating exhaust pressure upstream of the turbocharger turbine based on soot loading of the particulate filter; and reducing intake airflow if the estimated exhaust pressure is greater than a threshold, wherein the threshold is based on a pressure that will force open an exhaust valve when the exhaust valve would otherwise be closed. ### Claim 13 (depends on 12) The method of claim 12, wherein the threshold is further based on a spring wear of the exhaust valve over a life of the engine. ### Claim 14 (depends on 12) The method of claim 12, wherein the threshold is further based on one or more of engine speed and intake manifold pressure. ### Claim 15 (depends on 12) The method of claim 12, wherein the threshold is further based on cam timing. ### Claim 16 (depends on 15) The method of claim 15, wherein reducing intake airflow includes, during a first condition, reducing intake airflow via adjustments to an intake throttle opening, and during a second condition, reducing intake airflow via adjustments to an intake valve and/or intake cam timing. ### Claim 17 An engine system, comprising: an engine including an intake and an exhaust; an engine cylinder including an intake valve and an exhaust valve; a turbocharger for providing a boosted intake airflow, the turbocharger including an exhaust turbine; an intake throttle; an exhaust wastegate; an intake cam for adjusting an intake valve timing; a particulate filter coupled downstream of the exhaust turbine; a pressure sensor coupled downstream of the exhaust turbine; and a controller with computer readable instructions stored on non-transitory memory for: operating the engine with boost enabled and with positive valve overlap to blow-through an amount of boosted air from the intake to the exhaust via the engine cylinder; estimating exhaust pressure upstream of the exhaust turbine based on soot loading of the particulate filter; and if the estimated exhaust pressure is greater than a threshold, reducing one or more of intake airflow via the intake throttle and the amount of blow-through boosted air, wherein reducing the amount of blow-through boosted air includes adjusting a timing of the intake cam to reduce the positive valve overlap between an intake valve and an exhaust valve. ### Claim 18 (depends on 17) The engine system of claim 17, wherein the reducing includes: only reducing intake airflow via the intake throttle when engine speed is higher than a first speed threshold, only reducing the amount of blow-through boosted air when the engine speed is lower than a second speed threshold and engine load is higher than a load threshold, and reducing each of intake airflow via the intake throttle and the amount of blow-through boosted air when the engine speed is between the first speed threshold and the second speed threshold and the engine load is higher than the load threshold.