Systems and methods provide deceleration fuel cutoff regeneration of a gas particulate filter. A powertrain system includes an exhaust system containing the gas particulate filter, which is configured to collect particulate matter from an exhaust gas stream of the powertrain system. A temperature sensor is configured to monitor a temperature of the gas particulate filter. A loading monitor, such as a sensor and/or a model, is configured to provide a loading input of particulate loading of the gas particulate filter. At least one controller is configured to: determine, by comparing the loading input to stored values, whether the gas particulate filter requires the regeneration; effect a warmup of the gas particulate filter when the determination shows the gas particulate filter requires the regeneration; and initiate the regeneration when a value received from the temperature sensor meets a minimum threshold level.

Methods and systems are provided for heating a catalyst via a catalyst heater are presented. In one example, the catalyst may be heated to provide a minimum amount of time for the catalyst to reach a threshold temperature. In another example, the catalyst heater may be heated to minimize an amount of power that is used to heat the catalyst.

An engine system is disclosed. The engine system may have an engine having an accessory end and a drive end opposite the accessory end. The engine system may also have a turbocharger arrangement located adjacent the accessory end. The turbocharger arrangement may be configured to receive exhaust from the engine and to deliver compressed air to the air cooling arrangement. Further, the engine system may have an air cooling arrangement located adjacent the accessory end and configured to deliver fresh air to the engine. In addition, the engine system may have a mixing duct extending from the accessory end to the drive end and configured to receive the exhaust from the turbocharger arrangement. The engine system may also have an after-treatment system located adjacent the drive end. The after-treatment system may be configured to receive the exhaust from the mixing duct and to discharge the exhaust to an ambient.

A control device is capable of executing: an ignition time calculation process of calculating a target ignition time of an ignition plug; a stop process of stopping combustion control for some cylinders of a plurality of cylinders; and a compensation process of controlling a motor generator during the stop process, such that the motor generator compensates a drive power that is lost due to the stop of the combustion control. The control device prohibits the execution of the stop process when the target ignition time calculated in the ignition time calculation process is on a retard side of a predetermined prescribed time.

Various methods and arrangements for improving fuel economy and noise, vibration, and harshness (NVH) in a skip fire controlled engine are described. An engine controller dynamically selects a gas spring type for a skipped firing opportunity. Determination of the skip/fire pattern and gas spring type may be made on a firing opportunity by firing opportunity basis.

A system for particulate filter regeneration includes a pre-converter universal heated exhaust gas oxygen (UHEGO) sensor disposed upstream from a three-way catalytic (TWC) converter and a particulate filter (PF), and a post-converter UHEGO sensor disposed downstream from the TWC converter and upstream from the PF. An engine controller for an internal combustion engine (ICE) and in communication with the pre-converter UHEGO sensor and the post-converter UHEGO sensor is included. The engine controller is configured to determine an amount of particulate mass accumulated in the PF during operation of the ICE and deactivate at least one of a plurality of cylinders of the ICE such that a deactivated cylinder intake air (DCIA) pass-through volume flows through the at least one deactivated cylinder and into the TWC converter and the PF. The DCIA pass-through volume is a function of the determined amount of particulate mass accumulated in the PF.

Systems and methods are described for coordinating the regeneration of a gasoline particulate filter to a time duration when engine output falls below a predetermined load threshold selected to indicate a low power state of the engine. In one particular example, the engine is configured to adjust engine operations to regenerate the particulate filter responsive to engine output falling below a predetermined low power threshold, the regeneration further based on an estimated duration that the output falls continuously below the low power threshold. The system and methods described advantageously allow for either full or partial regeneration events to be performed based on the estimated duration of the engine output below the low power threshold.

A system and method for utilizing fuel as an on-board reductant for selective catalytic reduction of NOx is provided and includes a controller for controlling an engine to produce a lean first exhaust stream and a rich second exhaust stream that are received in respective first and second passageways of a dual path aftertreatment system. The rich second exhaust stream reacts with NOx stored in a NOx storage and reduction catalyst of the second passageway to regenerate this catalyst and generate ammonia. The first exhaust stream and the second exhaust stream having the generated ammonia are combined in a downstream common passageway to form a combined lean exhaust gas stream where the ammonia carried therein is stored or used by an SCR catalyst of the common passageway for NOx reduction. The engine is subsequently controlled to produce a rich first exhaust stream and a lean second exhaust stream.

A multi-cylinder engine exhaust structure disclosed herein includes: four branched exhaust pipes respectively communicating with four cylinders classified into two groups, each being comprised of two of the four cylinders with discontinuous exhaust strokes; two intermediate collecting pipes, each being formed by combining associated two of the four branched exhaust pipes respectively communicating with the two cylinders in an associated one of the two groups; a last collecting pipe formed by combining these intermediate collecting pipes; and an exhaust gas purifier coupled to an exhaust gas downstream end of the last collecting pipe. Two of the four branched exhaust pipes respectively communicating with two of the four cylinders to be activated as two active cylinders while the engine is performing a cylinder-cutoff operation are shorter than the two other branched exhaust pipes respectively communicating with the two other cylinders to be deactivated as two idle cylinders during the cylinder-cutoff operation.

A system includes an exhaust aftertreatment system in exhaust gas receiving communication with an engine including a plurality of cylinders where the engine is structured to operate according to low load conditions and where a controller is structured to determine that at least one diesel emissions fluid (DEF) doser is frozen based on at least one of an ambient air temperature and a DEF source temperature. The controller is structured to operate the engine according to a skip-fire mode in response to a DEF flag indicating that the at least one DEF doser is frozen. The skip-fire mode comprises firing a portion of the plurality of cylinders that is less than a total amount of cylinders of the plurality of cylinders. The controller is structured to discontinue the skip-fire mode in response to determining that the at least one DEF doser is likely thawed.