Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

Abstract: Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Engine knock background noise levels determined during all cylinders operating mode may be determined via two filters that are constructed in parallel. Output of the two filters may be the basis for determining the presence or absence of engine knock.

Abstract: Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Engine background noise levels for detecting engine knock may be the basis for determining whether or not the engine is operating in a cylinder deactivation mode. Further, select variable engine displacement modes may be avoided so that engine background noise level changes may be reduced to improve engine knock detection.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be determined via adjusting timing of a knock window or timing of the individual noise sources.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system. The methods and system provide for repurposing the engine knock control system to detect and mitigate piston slap. The methods and systems also seek to increase the signal to noise ratio for detecting piston slap.

Abstract: Sensors in a vehicle detect execution of a sign language symbol. The sign language symbol invokes a vehicle interface function. In some embodiments, the sign language symbol is an ASL sign. Sensors include three-dimensional optical, ultrasonic, or other sensors. The locations of targets (fingertips, knuckles, palm, etc.) are detected in the individual outputs of the sensors. The locations of targets determined from the outputs of multiple sensors may be associated with one another and filtered, such as using an RBMCDA algorithm and Kalman filtering. The system may be calibrated to detect each symbol by measuring the target locations with the user executing the each symbol.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system. The method and system may increase opportunities to learn one or more engine knock background noise levels via changing poppet valve timing and/or fuel injection timing. The method and system may also improve knock detection if knock sensor degradation is suspected.

Abstract: Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Engine knock background noise levels determined during all cylinders operating mode may be applied when one or more cylinders are deactivated to determine the presence or absence of engine knock. Additionally, engine knock background noise levels determined during all cylinders operating mode may be applied when one or more cylinders are reactivated such that the engine operates with all cylinder combusting so that the possibility of indicating knock when knock is not present may be avoided.

Abstract: Methods and systems are provided for controlling operating of a split exhaust engine system including a scavenge exhaust gas recirculation system based on a composition of constituents within a total flow through the scavenge exhaust gas recirculation system. In one example, a method may include adjusting an engine operating parameter in response to individual flows of each of burnt gases, fresh air, and fuel to an intake passage, upstream of a compressor, from a scavenge manifold coupled to scavenge exhaust valves, the individual flows of each of the burnt gases, fresh air, and fuel determined based on a valve opening overlap between the scavenge exhaust valves and intake valves of the engine.

Abstract: Methods and systems are provided for adjusting operation of a split exhaust engine system based on a total flow of gases through a scavenge exhaust gas recirculation system of the split exhaust engine system. In one example, a method may include setting a cam timing correction based on a difference between a first value and a second value of a flow through an exhaust gas recirculation (EGR) passage, the first value determined based on a first parameter set including a cylinder valve overlap area and the second value determined based on a second parameter set not including the cylinder valve overlap area, and operating at least one of an intake cam and an exhaust cam at a corrected timing using the cam timing correction. In this way, the flow through the EGR passage may be adjusted even without active control of a valve coupled in the EGR passage.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

Abstract: Methods and systems are provided for adjusting operation of a split exhaust engine system based on a total flow of gases through a scavenge exhaust gas recirculation system of the split exhaust engine system. In one example, a method may include adjusting engine operation in response to a flow of gases to an intake passage, upstream of a compressor, from a scavenge manifold coupled to scavenge exhaust valves, the flow of gases determined based on a valve opening overlap between the scavenge exhaust valves and intake valves of an engine, the scavenge exhaust valves opened at a different time than blowdown exhaust valves coupled to a blowdown manifold coupled to a turbine.

Abstract: Methods and systems are provided for adjusting operation of a split exhaust engine system based on a total flow of gases through a scavenge exhaust gas recirculation system of the split exhaust engine system. In one example, a method may include setting a cam timing correction based on a difference between a first value and a second value of a flow through an exhaust gas recirculation (EGR) passage, the first value determined based on a first parameter set including a cylinder valve overlap area and the second value determined based on a second parameter set not including the cylinder valve overlap area, and operating at least one of an intake cam and an exhaust cam at a corrected timing using the cam timing correction. In this way, the flow through the EGR passage may be adjusted even without active control of a valve coupled in the EGR passage.

Abstract: Methods and systems are provided for characterizing aged fuel, which loses volatility over time. In one example, a method may include estimating a fuel vapor pressure during an engine cold start using a pre-determined fuel distillation curve and adjusting one or more combustion parameters based on the estimated fuel vapor pressure. Because the fuel vapor pressure directly relates to the fuel volatility, adjusting the one or more combustion parameters based on the estimated fuel vapor pressure may reduce aged fuel-related engine performance degradation, such as hesitation and emissions during cold start.

Abstract: Methods and systems are provided for controlling operating of a split exhaust engine system including a scavenge exhaust gas recirculation system based on a composition of constituents within a total flow through the scavenge exhaust gas recirculation system. In one example, a method may include adjusting an engine operating parameter in response to individual flows of each of burnt gases, fresh air, and fuel to an intake passage, upstream of a compressor, from a scavenge manifold coupled to scavenge exhaust valves, the individual flows of each of the burnt gases, fresh air, and fuel determined based on a valve opening overlap between the scavenge exhaust valves and intake valves of the engine.

Abstract: Methods and systems are provided for adjusting operation of a split exhaust engine system based on a total flow of gases through a scavenge exhaust gas recirculation system of the split exhaust engine system. In one example, a method may include adjusting engine operation in response to a flow of gases to an intake passage, upstream of a compressor, from a scavenge manifold coupled to scavenge exhaust valves, the flow of gases determined based on a valve opening overlap between the scavenge exhaust valves and intake valves of an engine, the scavenge exhaust valves opened at a different time than blowdown exhaust valves coupled to a blowdown manifold coupled to a turbine.

Abstract: Methods and systems are provided for adjusting amount of directly injected fuel scavenged via a second exhaust manifold of a split exhaust engine system. In one example, a method may include adjusting a start of injection of a fuel direct injection into an engine cylinder, the cylinder including a first exhaust valve coupled to a first exhaust manifold and a second exhaust valve coupled to a second exhaust manifold, the second exhaust manifold coupled to an intake of the engine, based on a closing timing of the second exhaust valve and dependent on an operating condition, and adjusting a position of a bypass valve of the second exhaust manifold based on the adjusted start of injection. In this way, the amount of scavenged fuel may be increased or decreased based on the operating condition.

Abstract: Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

Abstract: Methods and systems are provided for estimating ethanol content in fuel, water content in fuel, and an age of the fuel in a vehicle engine. In one example, a method may include estimating fuel ethanol content, water content, or fuel age based on a resonant frequency (f) of pressure pulsations, a change in fuel rail pressure (?p), and a damping coefficient (?) of pressure pulsations in the fuel rail as estimated after a fuel injection or a pump stroke. One or more engine operating parameters may be adjusted based on the estimated fuel ethanol content, water content, and fuel age.