Abstract: Methods and systems are provided for improving engine exhaust emissions while enabling exhaust catalyst regeneration following an engine lean event. Prior to a VDE event, or prior to an engine idle-stop, ammonia is produced and stored on an exhaust underbody SCR catalyst. Then, during the engine restart after the VDE mode or the idle-stop, the stored ammonia is used to treat exhaust NOx species while an upstream exhaust underbody three-way catalyst is regenerated.

Abstract: Methods and systems are provided for adjusting cylinder valve timings to enable a group of cylinders to operate and combust while another group of cylinders on a second are selectively deactivated. Valve timing may be adjusted to allow flow of air through the inactive cylinders to be reduced, lowering catalyst regeneration requirements upon reactivation. The valve timing may alternatively be adjusted to enable exhaust gas to be recirculated to the active cylinders via the inactive cylinders, providing cooled EGR benefits.

Abstract: Methods and systems are provided for adjusting cylinder valve timings to enable a group of cylinders to operate and combust while another group of cylinders on a second are selectively deactivated. Valve timing may be adjusted to allow flow of air through the inactive cylinders to be reduced, lowering catalyst regeneration requirements upon reactivation. The valve timing may alternatively be adjusted to enable exhaust gas to be recirculated to the active cylinders via the inactive cylinders, providing cooled EGR benefits.

Abstract: Methods and systems are provided for operating an engine including an exhaust treatment system coupled to an engine exhaust, the exhaust treatment system further coupled to an engine intake via an exhaust gas recirculation (EGR) system. One example method comprises, operating in a first mode including routing exhaust gas through the exhaust treatment system to an exhaust tailpipe; operating in a second mode including routing exhaust gas through the exhaust treatment system to an engine intake via the EGR system, and operating in a third mode including routing exhaust gas to an engine intake through the EGR system while bypassing the exhaust treatment system.

Abstract: Methods and systems are provided for selecting a group of cylinders for selective deactivation, in a variable displacement engine system, based at least on a regeneration state of an exhaust catalyst. The position of one or more valves and throttles may be adjusted based on the selective deactivation to reduce back-flow through the disabled cylinders while also maintaining conditions of a downstream exhaust catalyst. Pre-ignition and knock detection windows and thresholds may also be adjusted based on the deactivation to improve the efficiency of knock and pre-ignition detection.

Abstract: Methods and systems are provided for selecting a group of cylinders for selective deactivation, in a variable displacement engine system, based at least on a regeneration state of an exhaust catalyst. The position of one or more valves and throttles may be adjusted based on the selective deactivation to reduce back-flow through the disabled cylinders while also maintaining conditions of a downstream exhaust catalyst. Pre-ignition and knock detection windows and thresholds may also be adjusted based on the deactivation to improve the efficiency of knock and pre-ignition detection.

Abstract: A method of operating a vehicle including an engine is provided. The engine may include at least one cylinder, a boosting device to boost intake air to the at least one cylinder, a fuel tank, a fuel vapor canister to store fuel vapors vented from the fuel tank, and an emission control device to treat exhaust gas from the engine. The boosting device includes a compressor at least partially driven by an electric motor. The method includes during an engine cold start condition, operating the electric motor of the boost device to boost intake air, directing the boosted intake air through the fuel vapor canister to release a fuel vapor stored in the fuel vapor canister, directing the fuel vapor from the fuel vapor canister to the engine, and performing combustion in the at least one cylinder using the fuel vapor during the engine starting.

Abstract: Systems, methods, and computer readable storage media are described in which exhaust gas is routed to a hydrocarbon retaining device during starting, and purged to the engine intake manifold. Various alternative approaches are described for controlling operation and diagnosing degradation. Further, various interrelated configurations are described.

Abstract: Embodiments for an engine exhaust are provided. In one example, a method comprises adjusting a fuel injection amount based on a fractional oxidation state of a catalyst, the fractional oxidation state based on reaction rates of a plurality of exhaust gas species throughout a catalyst longitudinal axis and a set of axially-averaged mass balance and energy balance equations for a fluid phase and a washcoat of the catalyst. In this way, a simplified catalyst model may be used to control air-fuel ratio.

Abstract: Systems and methods for monitoring an exhaust gas sensor coupled in an engine exhaust are provided. In one example approach, a method comprises indicating exhaust gas sensor degradation based on a downstream exhaust gas sensor responding before the upstream exhaust gas sensor during a commanded change in air-fuel ratio.

Abstract: A method for monitoring an exhaust gas sensor coupled in an engine exhaust is provided. In one embodiment, the method comprises indicating exhaust gas sensor degradation based on a time delay and line length of each sample of a set of exhaust gas sensor responses collected during a commanded change in air-fuel ratio. In this way, the exhaust gas sensor may be monitored utilizing robust parameters in a non-intrusive manner.

Abstract: Systems, methods, and computer readable storage media are described in which exhaust gas is routed to a hydrocarbon retaining device during starting, and purged to the engine intake manifold. Various alternative approaches are described for controlling operation and diagnosing degradation. Further, various interrelated configurations are described.

Abstract: Systems, methods, and computer readable storage media are described in which exhaust gas is routed to a hydrocarbon retaining device during starting, and purged to the engine intake manifold. Various alternative approaches are described for controlling operation and diagnosing degradation. Further, various interrelated configurations are described.

Abstract: Methods and systems are provided for controlling the automatic shutdown of an idling vehicle engine. When the vehicle is parked in an enclosed space, the idling engine may be automatically shutdown, while when the vehicle is parked in an open space, the automatic shutdown may be delayed based on an ambient temperature. In this way, the vehicle cabin may be maintained at a temperature that provides enhanced driver comfort while allowing wasteful engine idling to be reduced.

Abstract: Embodiments for predicting catalyst function are disclosed. One example embodiment includes applying a set of parameter readings for a given sample to a support vector machine to generate a classification output, recording a plurality of classification outputs for a plurality of successive samples over a first duration, and indicating catalyst degradation if a threshold percentage of the classification outputs indicates degraded catalyst performance. In this way, catalyst degradation may be indicated using a simplified model that does not require extensive calibration.

Abstract: Method and systems are provided for operating an engine having a hydrocarbon retaining system coupled to an engine exhaust and an engine intake. During an engine cold start, routing exhaust gas to the hydrocarbon retaining system to store hydrocarbons in the hydrocarbon retaining system. Then, depending on temperature, the hydrocarbons are purged with varying amounts of exhaust gas and fresh air in order to maintain proper temperature control.

Abstract: A method of operating a vehicle including an engine is provided. The engine may include at least one cylinder, a boosting device to boost intake air to the at least one cylinder, a fuel tank, a fuel vapor canister to store fuel vapors vented from the fuel tank, and an emission control device to treat exhaust gas from the engine. The boosting device includes a compressor at least partially driven by an electric motor. The method includes during an engine cold start condition, operating the electric motor of the boost device to boost intake air, directing the boosted intake air through the fuel vapor canister to release a fuel vapor stored in the fuel vapor canister, directing the fuel vapor from the fuel vapor canister to the engine, and performing combustion in the at least one cylinder using the fuel vapor during the engine starting.

Abstract: Systems, methods, and computer readable storage media are described in which exhaust gas is routed to a hydrocarbon retaining device during starting, and purged to the engine intake manifold. Various alternative approaches are described for controlling operation and diagnosing degradation. Further, various interrelated configurations are described.

Abstract: Methods and systems are provided for selecting a group of cylinders for selective deactivation, in a variable displacement engine system, based at least on a regeneration state of an exhaust catalyst. The position of one or more valves and throttles may be adjusted based on the selective deactivation to reduce back-flow through the disabled cylinders while also maintaining conditions of a downstream exhaust catalyst. Pre-ignition and knock detection windows and thresholds may also be adjusted based on the deactivation to improve the efficiency of knock and pre-ignition detection.

Abstract: A diagnostic method for an engine having a valve for controlling dilution of intake air. The method comprises, during engine fueling, indicating a degradation of the valve when the valve is commanded closed but sensor output corresponds to an oxygen level below that of air. The method further comprises, absent engine fueling, indicating degradation of the sensor when the valve is commanded closed but the sensor output corresponds to an oxygen level below that of air.