Methods and systems are provided for a close-coupled aftertreatment device. In one arrangement, a system may include an engine comprising separate first and second overall exhaust lines, where a blow-off line branches off of the second overall exhaust line, and where the close-coupled aftertreatment device is arranged in the blow-off line and configured to receive exhaust gases during at least a cold-start of the engine.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between the intake passage and the first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and the exhaust passage may be adjusted based on a measured pressure in the first exhaust manifold.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, each of a first valve positioned in an exhaust gas recirculation (EGR) passage, the EGR passage coupled between the intake passage and the first exhaust manifold coupled to a first set of cylinder exhaust valves, and a second valve positioned in a flow passage coupled between the first exhaust manifold and the exhaust passage may be adjusted based on a measured pressure in the first exhaust manifold.

A method of controlling oxygen purge of a three-way catalyst may include: performing a fuel cut-off; determining whether a fuel cut-in condition is satisfied after the fuel cut-off; calculating an optimum valve overlap according to an intake amount, an engine rotation speed, and an ignition timing if the fuel cut-in condition is satisfied after the fuel cut-off; controlling a CVVD apparatus to be at the optimum valve overlap; and performing the oxygen purge at the optimum valve overlap.

Calibration techniques for forced-induction engines having low pressure cooled exhaust gas recirculation (LPCEGR) systems include commanding an EGR to a fully-closed position, after the EGR valve has reached the fully-closed position, commanding the engine to operate at fixed steady-state conditions for a calibration period, wherein the fixed steady-state conditions comprise at least a fixed throttle valve angle, a fixed injected fuel mass, and a fixed cylinder air/fuel ratio (AFR), during the calibration period, increasingly opening the EGR valve and monitoring a AFR of exhaust gas produced by the engine, calibrating an EGR fraction estimation and EGR transport delay model based on previously measured and/or modeled total engine flow and the monitored exhaust gas AFR during the calibration period, and storing the calibrated model at a memory of a controller of the engine for future usage to improve engine operation.

Methods and systems are provided for reducing engine compression torque when an engine having a split exhaust system is spun unfueled. In one example, a method may include maintaining closed a blowdown exhaust valve of a cylinder, the blowdown exhaust valve coupled to a first exhaust manifold that directs gases from the cylinder to a catalyst, and opening a scavenge exhaust valve of the cylinder, the scavenge exhaust valve coupled to a second exhaust manifold that directs gases from the cylinder to an exhaust gas recirculation system. In this way, compression of gases within they cylinder is reduced while gas flow to the catalyst is prevented.

An object of the present invention is to provide an exhaust gas purification system which exhibits high exhaust gas purification performance. The present invention provides an exhaust gas purification system including: a carrier containing aluminum oxide; an exhaust gas purification device including a catalyst provided on the carrier and containing gallium, and connected to an internal combustion engine; and a system connected to the exhaust gas purification device for increasing an oxygen concentration. The system for increasing an oxygen concentration provides an oxygen concentration higher than that of a post combusted gas of the internal combustion engine.

A system includes an exhaust aftertreatment system including a particulate filter and a controller. The controller is configured to: receive a particulate filter regeneration event trigger; receive information, the information comprising a temperature regarding the particulate filter; determine the temperature regarding the particulate filter is below a temperature threshold associated with a particulate filter regeneration event; and responsive to determining the temperature regarding the particulate filter is below the temperature threshold, command the engine to operate in a cylinder deactivation mode, whereby at least one cylinder of a plurality of cylinders of the engine is deactivated.

An engine consumes fuel and air to generate an exhaust gas stream. An exhaust system channels the exhaust gas stream from the engine to a tailpipe. An aftertreatment system is included in the exhaust system and includes a catalyst. An exhaust throttle valve is disposed in the exhaust system downstream from the aftertreatment system. An actuator controls an amount of air pumped through the engine. A controller operates the exhaust throttle valve and/or the actuator to control emissions from the exhaust system during a cold start and following a deceleration fuel cutoff event.

A method for controlling the operation of an engine system in a vehicle is provided The engine system includes an engine configured to operate in at least a two-stroke combustion mode and a four-stroke combustion mode, and an exhaust aftertreatment system, EATS configured to reduce emissions from the engine exhausts. The method comprising estimating or predicting the temperature of the EATS; estimating or predicting the emissions out of the EATS; n response of that the temperature of the EATS is below a predetermined temperature threshold, and that the emissions out of the EATS is above a predetermined emission threshold, performing a primary NOx emission reducing activity by operating the engine in a two-stroke combustion mode; subsequently to initiating the operation of the engine in a two-stroke combustion mode, and in response of that the emissions out of the EATS is below the predetermined emission threshold, changing engine operation from the two-stroke combustion mode to a four-stroke combustion mode.