Abstract: Various methods and systems are provided for adjusting a flow of exhaust gas in an exhaust gas recirculation system. In one embodiment, a method for an engine comprises controlling a flow of exhaust gas through an exhaust gas recirculation system of an engine system based on a choke level of a turbocharger. For example, the flow of exhaust gas in the exhaust gas recirculation system may be reduced to within a threshold of a choke level of the turbocharger, in response to an ambient condition.

Abstract: Various systems and methods are provided for controlling operation of a turbocharger compressor. In one example, a system includes a turbocharger including a turbine positioned in an exhaust passage and a compressor positioned in an intake passage, an engine bypass passage having an inlet fluidically coupled to an outlet of the compressor and an outlet fluidically coupled to an inlet of the turbine, an engine bypass valve to control flow through the engine bypass passage, and a controller configured to adjust a position of the engine bypass valve to maintain compressor operation within a designated compressor efficiency region.

Abstract: Various methods and systems are provided for adjusting an air-fuel ratio for combustion in an engine. In one embodiment, a method for an engine (e.g., a method for controlling an engine system) comprises responding to a sensed change in a load on the engine, or indications of engine knock or misfire, by one or more of: altering a speed of the engine, adjusting a fueling flow rate into at least one cylinder of the engine, and adjusting a position of a valve in a bypass passage configured to direct compressed intake air away from cylinders of the engine to obtain a determined air-fuel ratio; and thereby maintaining an air-fuel ratio in a determined range.

Abstract: Various methods and systems are provided for generating exhaust energy and converting exhaust energy to electrical energy while an engine is not running. In one example, a system for an engine comprises: a first turbocharger including a first compressor driven by a first turbine, the first turbine disposed in an exhaust of the engine; a fuel burner fluidly coupled to the exhaust upstream of the first turbine; a generator coupled to one of the first turbine or an auxiliary, second turbine fluidly coupled to the exhaust downstream of the fuel burner; and one or more bypass valves configured to adjust a flow of air that bypasses the engine and is delivered to the fuel burner.

Abstract: Various methods and systems are provided for a detecting surge of a turbocharger in an engine system. In one example, system includes a turbocharger including a compressor coupled to a turbine and a controller and sensor system configured to detect a surge event of the turbocharger based on at least one of a rate of change of a pressure measured by sensors downstream of the compressor and a measured rate of change of turbine speed, store operational data associated with the surge event in memory of the controller, and determine a performance of the turbocharger based at least in part on one or more of a cumulative number of detected surge events, a magnitude of detected surge events, or associated operational data.

Abstract: Various methods and systems are provided for controlling air flow in a two-stage turbocharger. In one example, an engine method comprises adjusting one or more exhaust gas recirculation valves to maintain a first turbocharger within a first air flow range, and adjusting a turbocharger bypass valve to maintain a second turbocharger within a second air flow range.

Abstract: Various methods and systems are provided for adjusting a turbine boost control actuator based on a single common reference value. In one example, a method for an engine includes adjusting a turbine boost control actuator to control an intake manifold pressure to a limit, the limit based at least in part on one or more of peak cylinder pressure, turbine speed, and a pressure difference across a turbine.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to a sensed or estimated intake oxygen fraction by controlling an exhaust gas recirculation (EGR) amount supplied to an engine to maintain a level of particulate matter (PM) in a determined PM range and a level of NOx in a determined NOx range, and adjusting a target intake manifold oxygen fraction or target intake manifold EGR fraction in response to a NOx sensor feedback signal.

Abstract: A method involves comparing a determined operating parameter of an engine, with a predefined operating parameter. The method further involves controlling a fuel source and an ignition source of the engine so as to operate at least one engine cylinder in a skip fire mode for at least one cycle of a crank shaft when the determined operating parameter is greater than the predefined operating parameter. The controlling involves transitioning the fuel source from a normal mode to the skip fire mode for the at least one cycle of the crank shaft either before transitioning the ignition source from the normal mode to the skip fire mode or when the ignition source is operated in the normal mode.

Abstract: Various systems and method for controlling exhaust gas recirculation (EGR) in an internal combustion engine are provided. In one embodiment, a method includes during a first operating condition, directing exhaust gas from a first cylinder group into an engine air intake stream and directing substantially no exhaust gas from a second cylinder group to the engine air intake stream. The method further includes during a second operating condition, directing exhaust gas from the second cylinder group through a turbocharger bypass into the engine air intake stream and reducing a fuel injection amount of the first cylinder group relative to a fuel injection amount of the second cylinder group.

Abstract: Various methods and systems are provided for adjusting an air-fuel ratio for combustion in an engine. In one embodiment, a method for an engine (e.g., a method for controlling an engine system) comprises responding to a sensed change in a load on the engine, or indications of engine knock or misfire, by one or more of: altering a speed of the engine, adjusting a fueling flow rate into at least one cylinder of the engine, and adjusting a position of a valve in a bypass passage configured to direct compressed intake air away from cylinders of the engine to obtain a determined air-fuel ratio; and thereby maintaining an air-fuel ratio in a determined range.

Abstract: Various systems are provided for delivering fuel to an engine. In one example, a system includes a controller and a fluid system configured to maintain a fluid at a pressure downstream of a check valve. The controller may be configured to determine if a leak is present in the fluid system based on a first pressure decay rate of the fluid system, and responsive to identifying that a leak is present in the fluid system, differentiate between an internal leak and an external leak based on a leak flow rate as fluid system pressure decreases.

Abstract: Fuel injector wear methodologies for use with internal combustion engines include a method that determines power of the engine and/or fuel flow of a fuel injector(s) associated with a cylinder the engine; obtains a duration of a fuel injection event from the injector(s) associated with the cylinder(s) of the engine; compares the power, the fuel flow, and/or the duration with a reference value; and then adjusts the fuel injection timing of the fuel injector(s), based on the comparison. Another method adjusts operation of an engine includes: comparing two (or more) engine models, wherein one model is related to a fuel injection event duration of the engine or a modeled fuel quantity being supplied to the engine and then adjusting the fuel injection timing of a fuel injector(s) of the engine, based on the comparison.

Abstract: Various methods and systems are provided for engine operation with a degraded turbocharger. In one embodiment, a method for an engine comprises reducing mass flow through a first turbocharger while continuing engine operation and adjusting operation of a second turbocharger in response to detected degradation of the first turbocharger.

Abstract: Various systems and method for controlling exhaust gas recirculation (EGR) in an internal combustion engine are provided. In one embodiment, a method includes injecting fuel to a subset of cylinders that includes less than all cylinders of a first cylinder group to obtain a target EGR rate. The first cylinder group provides exhaust gas through an exhaust gas recirculation (EGR) passage structure fluidly coupled between the first cylinder group and an intake passage structure. The method further includes injecting fuel to at least one cylinder of a second cylinder group. The second cylinder group provides substantially no exhaust gas through the EGR passage structure.

Abstract: Various methods for controlling EGR rate are disclosed. In one embodiment, a method comprises routing at least a portion of exhaust from a first exhaust manifold to an intake manifold, and not to atmosphere, the first exhaust manifold exclusively coupled to a first cylinder group. The method further includes routing exhaust from at least one additional exhaust manifold coupled to a corresponding at least one additional cylinder group to atmosphere, and during a first engine operating condition where an engine fuel demand is below a threshold demand, not injecting fuel to each of a subset of cylinders in the first cylinder group while injecting fuel to a subset of all cylinders coupled to the at least one additional exhaust manifold, where a number of cylinders of the subset of cylinders in the first cylinder group decreases in response to an increase in a target EGR rate.

Abstract: Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to one or more of intake manifold air temperature (MAT), intake air flow rate, or a sensed or estimated intake oxygen fraction by changing an exhaust gas recirculation (EGR) amount to maintain particulate matter (PM) and NOx within a range, and then further adjusting the EGR amount based on NOx sensor feedback.

Abstract: Various methods and systems are provided for adjusting a turbine boost control actuator based on a single common reference value. In one example, a method for an engine includes adjusting a turbine boost control actuator to control an intake manifold pressure to a limit, the limit based at least in part on one or more of peak cylinder pressure, turbine speed, and a pressure difference across a turbine.

Abstract: Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Abstract: A method involves comparing a determined operating parameter of an engine, with a predefined operating parameter. The method further involves controlling a fuel source and an ignition source of the engine so as to operate at least one engine cylinder in a skip fire mode for at least one cycle of a crank shaft when the determined operating parameter is greater than the predefined operating parameter. The controlling involves transitioning the fuel source from a normal mode to the skip fire mode for the at least one cycle of the crank shaft either before transitioning the ignition source from the normal mode to the skip fire mode or when the ignition source is operated in the normal mode.