Abstract: Methods and systems are provided for calibrating a compressor surge line. In one example, a method may include adjusting the compressor surge line based on a vehicle speed in addition to a compressor pressure ratio. For example, at higher vehicle speeds, above a threshold vehicle speed, a less aggressive surge line calibration may be utilized in order to improve drivability while at lower vehicle speeds, below the threshold vehicle speed, a more aggressive surge line calibration may be utilized for NVH mitigation.

Abstract: Methods and systems for correcting cam angle measurements for engine-to-engine build variation are disclosed. In one example, a method comprises learning cam angle corrections to update a measured cam angle responsive to air-fuel ratio errors during selected conditions, and learning air and fueling errors responsive to the air-fuel ratio error otherwise. In this way, cam angle errors due to engine build variation may be corrected, thereby improving other air and fuel adaptation methods and improving engine emissions.

Abstract: Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

Abstract: Methods and systems are provided for identifying and rejecting asymmetric faults that cause engine emissions to be biased rich or lean. In one example, a method for an engine system comprises generating a UEGO sensor feedback set-point adjustment based on slower and faster time components within an outer loop of a catalyst control system; generating an inner-loop bias-offset correction from the slower time component; and indicating degradation of the engine system based on a comparison of the bias-offset correction to a degradation threshold. In this way, the total outer-loop control authority is increased while maintaining drivability and noise, vibration, and harshness (NVH) constraints and meeting emission standards in the presence of an air-to-fuel ratio biasing fault.

Abstract: Methods and systems are provided for exhaust leak management in an engine. The exhaust leakage management system may include a port disposed to capture leaked exhaust along a movable portion associated with a turbine. The exhaust leakage management system may also include a three-way valve at a bifurcation of the port, directing leaked exhaust either to a first passage fluidically connected to a crankcase of the engine or to a second passage fluidically connected to a downstream portion of an exhaust pipe, depending on engine operating conditions.

Abstract: A vehicle includes a transmission and a controller. The controller is configured to receive a torque request, calculate a Specific Fuel Consumption (SFC) for satisfying the torque request in an initial gear and in an alternate gear, and command the transmission to shift from the initial gear into the alternate gear in response to the calculated SFC for satisfying the torque request in the alternate gear being less than the calculated SFC for satisfying the torque request in the initial gear.

Abstract: Systems and methods are provided. In one example, a method for an engine comprises adjusting an air charge estimate for a first cylinder based on a firing pattern of a second cylinder. In this way, cylinder air charge estimates may be improved in real-time for an arbitrary cylinder firing pattern, thereby improving engine efficiency.

Abstract: Embodiments for testing a humidity sensor are provided. One example method comprises indicating degradation of a humidity sensor based on a humidity sensor output and output from an intake gas composition sensor. In this way, output from the intake gas composition sensor may be used to determine if the humidity sensor is degraded.

Abstract: Methods and systems are provided for detecting an air-fuel imbalance based on output from multiple degradation monitors. In one example, a method comprises, during feedback engine air-fuel ratio control responsive to output of an exhaust gas sensor positioned downstream of a catalyst, indicating a cylinder imbalance responsive to a catalyst transfer function determined only within a specified frequency range based on the exhaust gas sensor output after determining that the catalyst is nominal, and adjusting an actuator in response to the indicated cylinder imbalance. In this way, air-fuel ratio imbalances may be accurately identified and mitigated, thereby reducing emissions.

Abstract: Systems and methods for identifying and mitigating air-fuel imbalance faults specific to an engine cylinder are provided. In one embodiment, a method comprises indicating a cylinder imbalance by comparing time-aligned readings from exhaust gas oxygen sensors, the exhaust gas oxygen sensors positioned symmetrically opposite each other within an exhaust passage downstream of a catalyst. In this way, an air-fuel imbalance fault may be accurately detected in a non-uniform exhaust flow so that mitigating actions can be taken, resulting in reduced tailpipe emissions.

Abstract: Various approaches are described for air-fuel ratio control in an engine. In one example, a method include adjusting fuel injection from an anticipatory controller responsive to exhaust oxygen feedback of an exhaust gas sensor positioned upstream of an exhaust catalyst, the anticipatory controller including a first integral term and a second integral term, the second integral term correcting for past fuel disturbances. In this way, it is possible to provide fast responses to errors via the anticipatory controller, while corrected known past fueling errors, on average, via the second integral term.

Abstract: Methods and systems are provided for detecting an air-fuel imbalance based on output from multiple degradation monitors. In one example, a method comprises, during feedback engine air-fuel ratio control responsive to output of an exhaust gas sensor positioned downstream of a catalyst, indicating a cylinder imbalance responsive to a catalyst transfer function determined only within a specified frequency range based on the exhaust gas sensor output after determining that the catalyst is nominal, and adjusting an actuator in response to the indicated cylinder imbalance. In this way, air-fuel ratio imbalances may be accurately identified and mitigated, thereby reducing emissions.

Abstract: Various systems and methods for controlling a turbocharger of an engine via a wastegate are described. In one example, the wastegate is adjusted according to a difference between the boost pressure and the atmospheric pressure. In this manner, the interdependency between controlling the boost pressure and using the boost pressure to actuate the wastegate in a boost-based wastegate configuration may be reduced.

Abstract: Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

Abstract: Embodiments for testing a humidity sensor are provided. One example method comprises indicating degradation of a humidity sensor based on a humidity sensor output and output from an intake gas composition sensor. In this way, output from the intake gas composition sensor may be used to determine if the humidity sensor is degraded.

Abstract: A vehicle includes a transmission and a controller. The controller is configured to receive a torque request, calculate an SFC for satisfying the torque request in an initial gear and in an alternate gear, and command the transmission to shift from the initial gear into the alternate gear in response to the calculated SFC for satisfying the torque request in the alternate gear being less than the calculated SFC for satisfying the torque request in the initial gear.

Abstract: A method for determining cylinder blow-through air via engine volumetric efficiency is disclosed. In one example, the method provides a way to adjust cylinder blow-through to promote and control a reaction in an exhaust after treatment device. The approach may simplify cylinder blow-through calculations and improve engine emissions via providing improved control of constituents reaching an exhaust after treatment device.

Abstract: Methods and systems are provided for calibrating a compressor surge line. In one example, a method may include adjusting the compressor surge line based on a vehicle speed in addition to a compressor pressure ratio. For example, at higher vehicle speeds, above a threshold vehicle speed, a less aggressive surge line calibration may be utilized in order to improve drivability while at lower vehicle speeds, below the threshold vehicle speed, a more aggressive surge line calibration may be utilized for NVH mitigation.

Abstract: Embodiments for testing a humidity sensor are provided. One example method comprises indicating degradation of a humidity sensor based on a humidity sensor output and output from an intake gas composition sensor. In this way, output from the intake gas composition sensor may be used to determine if the humidity sensor is degraded.

Abstract: Systems and methods for estimating catalyst transfer function gain are disclosed. In one example, an air-fuel ratio forcing function is applied to a catalyst. Air-fuel ratios upstream and downstream of the catalyst are manipulated to determine a transfer function gain of the catalyst. The transfer function gain may be a basis for indicating the presence or absence of catalyst degradation.