Abstract: Systems and methods for unsticking intake and exhaust valves of an engine are described. In one example, valves that may be adjustably timed relative to an engine crankshaft position may be adjusted to unstick intake and/or exhaust valve that are stuck open or closed. In addition, fuel injection timing and spark timing may be adjusted in an effort to unstick intake and/or exhaust valves.

Abstract: Methods and systems for operating an engine with a pump that is driven via the engine are described. In one example, start of opening of an injector that supplies a fluid to an engine exhaust system is timed based on a period of the pump so that the output of the fluid injector may be repeatable in the presence of fluid pressure oscillations that are periodic with pump rotation.

Abstract: Methods and systems are provided for diagnostics of a gasoline particulate filter in an exhaust system. In one example, a method may include indicating degradation of a hose coupled across a particulate filter responsive to a difference between a first differential pressure and a second differential pressure being greater than a threshold, the first differential pressure measured by a differential pressure sensor positioned in the hose responsive to a downstream exhaust tuning valve being fully open, the second differential pressure measured by the differential pressure sensor responsive to the exhaust tuning valve being fully closed.

Abstract: Methods and systems are provided for diagnostics of a gasoline particulate filter in an exhaust system after confirming that specific conditions are met including that an exhaust tuning valve is not degraded. In one example, a method may include indicating degradation of a hose coupled across a particulate filter responsive to a difference between a first differential pressure and a second differential pressure being greater than a threshold, the first differential pressure measured by a differential pressure sensor positioned in the hose responsive to a downstream exhaust tuning valve being fully open, the second differential pressure measured by the differential pressure sensor responsive to the exhaust tuning valve being fully closed.

Abstract: Methods and systems are provided for diagnosing a gasoline particulate filter in an engine exhaust passage. A pressure-flow relationship of the filter is learned in a low engine speed and high engine speed range. Degradation of the filter is identified based on a substantial separation between the curve fits at the high and low speed range.

Abstract: Systems and methods for controlling and diagnosing air flow through a compressor without recirculating air flow through the compressor are presented. In one example, a position of an air flow control device located within a compressor housing is adjusted responsive to a request to diagnose flow through the compressor. The diagnostic may be performed while maintaining engine torque and speed.

Abstract: Methods and systems are provided for detecting NOx sensor degradation based on results from a NOx sensor self-diagnostic (SD) test performed after a key-off event. In one example, a method may comprise waiting a duration to perform a SD test of a NOx sensor after a key-off event until engine operating conditions stabilize and reach a set of qualifying conditions. One or more SD tests may be performed after waiting the duration, but outputs generated under conditions where one or more of a temperature at the sensor is greater than a threshold, and an oxygen concentration is outside a threshold range, may be excluded when determining whether or not the NOx sensor is degraded.

Abstract: Methods and systems are provided for indicating crankcase breach due to disconnection of a crankcase vent tube from an engine on a clean air side or broken crankcase vent tube. In one example, a maximum possible change in crankcase vent tube pressure is estimated for each pedal transient of a drive cycle. The change for a plurality of transients in averaged and compared to a threshold to identify vent tube disconnection.

Abstract: Methods and systems are provided for diagnosing a gasoline particulate filter in an engine exhaust passage. A pressure-flow relationship of the filter is learned in a low engine speed and high engine speed range. Degradation of the filter is identified based on a substantial separation between the curve fits at the high and low speed range.

Abstract: Methods and systems are provided for controlling particulate filter temperature during non-combustion conditions. In one example, a method for an engine includes responsive to a particulate filter temperature above a threshold temperature and while operating the engine with deceleration fuel shut-off (DFSO), fully closing a throttle valve configured to regulate flow of intake air to the engine, and responsive to intake manifold pressure dropping below a threshold pressure while the throttle valve is fully closed, adjusting a position of the throttle valve based on the particulate filter temperature.

Abstract: Methods and systems are provided for indicating crankcase breach due to disconnection of a crankcase vent tube from an engine on a clean air side or broken crankcase vent tube. In one example, a maximum possible change in crankcase vent tube pressure is estimated for each pedal transient of a drive cycle. The change for a plurality of transients in averaged and compared to a threshold to identify vent tube disconnection.

Abstract: Methods and systems for operating an engine and determining relative compression ratio differences from a reference cylinder are disclosed. In one example, an engine is rotated via a starter or another type of electric machine and engine deceleration rates related to each engine cylinder are determined. The engine deceleration rates form a basis for compression ratio factors for each engine cylinder.

Abstract: Methods and systems are provided for estimating maximum in-cylinder pressure for all engine cylinders while reducing the number of individual cylinders required for pressure sensing. Pressure sensing is performed for a single instrumented cylinder. For remaining non-instrumented cylinders, an engine speed-dependent correction factor is applied that compensates for compression pressure variation between cylinders due to intake valve closing differences.

Abstract: Methods and systems are provided for waking up a powertrain control module of an engine-driven vehicle during engine soak to perform an offset test of an exhaust NOx sensor. In one example, a method includes determining a duration to delay waking up the powertrain control module based on exhaust temperature at vehicle-off, waking up the powertrain control module after the duration has expired, and then initiating heating of the NOx sensor. After the NOx sensor lights off, heating continues for an additional duration before offset testing of the NOx sensor is performed.

Abstract: Methods and systems are provided for adjusting an active casing treatment of a compressor responsive to a predicted engine condition. In one arrangement, a controller may actuate a sleeve of a variable geometry compressor casing to a position selected based on each of a compressor pressure ratio and a mass flow through the compressor, as well as driver behavior and predicted road conditions; and adjust each of an EGR actuator and a boost actuator based on the selected position to maintain the compressor pressure ratio during the actuating.

Abstract: Methods and systems are provided for expediting exhaust particulate filter regeneration. In one example, an engine controller may generate an exotherm at the filter by operating engine cylinders with air-fuel imbalance while using electric assist to a turbocharger to meet a torque demand and raise an intake airflow to enhance the effect of the exotherm. Once heated, the filter may be regenerated by flowing extra air to the exhaust via an air pump and injecting extra fuel to an exhaust passage via an exhaust injector.

Abstract: Methods and systems are provided for controlling a turbocharged engine. In one arrangement, a method may include concurrently adjusting an exhaust recirculation gas flow and a turbine flow while adjusting geometry of a compressor to compensate for disturbance caused by the compressor adjustment.

Abstract: Methods and systems are provided for probabilistic on-board diagnostics. In one example, a method may include calculating a probabilistic metric for a sample of a measured operating condition of a vehicle system component, averaging a plurality of probabilistic metrics including the probabilistic metric for a plurality of samples including the sample, and determining whether the vehicle system component is degraded based on the averaged plurality of probabilistic metrics. In this way, the functionality of a vehicle system component may be continuously monitored without regard for specific diagnostic entry conditions.

Abstract: Methods and systems are provided for diagnostics of a gasoline particulate filter in an exhaust system. In one example, a method may include indicating degradation of a hose coupled across a particulate filter responsive to a difference between a first differential pressure and a second differential pressure being greater than a threshold, the first differential pressure measured by a differential pressure sensor positioned in the hose responsive to a downstream exhaust tuning valve being fully open, the second differential pressure measured by the differential pressure sensor responsive to the exhaust tuning valve being fully closed.

Abstract: Methods and systems are provided for controlling particulate filter temperature during non-combustion conditions. In one example, a method for an engine includes responsive to a particulate filter temperature above a threshold temperature and while operating the engine with deceleration fuel shut-off (DFSO), fully closing a throttle valve configured to regulate flow of intake air to the engine, and responsive to intake manifold pressure dropping below a threshold pressure while the throttle valve is fully closed, adjusting a position of the throttle valve based on the particulate filter temperature.