The invention relates to an internal combustion engine with an air intake system and an exhaust system is embodied as an internal combustion engine, in particular a gasoline engine, that is charged by means of an exhaust gas turbocharger. At least one three-way catalytic converter is arranged in the exhaust system of the internal combustion engine. Furthermore, a low-pressure exhaust gas recirculation system is provided that connects the exhaust system downstream from a turbine of the exhaust gas turbocharger and upstream from the at least one three-way catalytic converter to the air intake system upstream from a compressor of the exhaust gas turbocharger. The invention further relates to a method for exhaust aftertreatment of such an internal combustion engine.

When an amount of PM trapped by a GPF is large and a request for regeneration is made, a CPU determines whether an execution condition for executing a temperature increasing process is satisfied. At a point in time t1, at which the execution condition is satisfied, the CPU executes a scavenging process to assign 1 to a condition satisfaction flag Ftr, cause the air-fuel ratio of air-fuel mixture in cylinders #1, #3, and #4 to be the stoichiometric air-fuel ratio, and stop a combustion operation in a cylinder #2. After a point in time t2, which is after a combustion cycle, the CPU executes a temperature increasing process. The temperature increasing process causes the air-fuel ratio of the air-fuel mixture in the cylinders #1, #3, and #4 to be richer than the stoichiometric air-fuel ratio, and stops the combustion operation in the cylinder #2.

A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

Methods and systems are provided for an exhaust system. In one example, the exhaust system includes an aftertreatment device and a recirculation passage. A recirculation valve is positioned in the recirculation passage and configured to control an amount of recirculated exhaust gas flowing through the recirculation passage to the aftertreatment device. The exhaust system further includes a diverter valve configured to control a flow of engine exhaust gases to different portions of a catalyst of the aftertreatment device.

Methods and systems are provided for recirculation of an engine exhaust gas. The system includes an engine, an exhaust system configured to channel exhaust gas from the engine to an outlet, an aftertreatment device, an exhaust recirculation system configured to divert at least some of the exhaust gas as recirculated exhaust gas from a first position in the exhaust system downstream of the aftertreatment device, through a housing enclosing the aftertreatment device, and to a second position in the exhaust system upstream of the aftertreatment device, wherein the recirculated exhaust gas is combined with the exhaust gas at the second position, a controller configured to, by a processor, selectively operate the exhaust recirculation system to control the exhaust recirculation system to divert the exhaust gas and thereby cause the recirculated exhaust gas to be treated with the aftertreatment device more than once.

Methods, systems, and devices for operating an engine controller in a vehicle for managing motor torque smoothing. One controller is configured to select a periodic disruptive waveform generated over a period of time to approximate that is associated with the vehicle being at idle, determine a first harmonic sinusoid from a group of harmonic sinusoids that reduces the error between an approximated waveform and the disruptive waveform, and initiate a supplemental quantity of torque during the period of time based on the disruption quantity of torque.

A controller may determine that a regeneration process associated with an engine of a machine is active. The controller may obtain, based on determining that the regeneration process is active, information concerning a speed of the engine, information concerning a load of the engine, and information concerning a fuel rate of the engine. The controller may select, based on the information concerning the speed of the engine, the information concerning the load of the engine, and the information concerning the fuel rate of the engine, a control process, of a plurality of control processes, to control an intake manifold absolute pressure (IMAP) of the engine to facilitate the regeneration process. The controller may cause, according to the selected control process, adjustment of one or more components of a variable geometry turbocharger (VGT) of the engine and an intake throttle valve (ITV) of the engine.

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.

Methods and systems for maintaining a temperature of catalyst above a threshold temperature during vehicle braking and coasting is described. In one example, engine pumping work may be increased without increasing flow of cool fresh air through the engine's exhaust system to provide a desired level of engine braking. The net air flow through the engine may be reduced via activating a decompression actuator.

The subject matter of this specification can be embodied in, among other things, an engine system that includes an intake manifold configured to receive and convey air to a combustion chamber, an intake valve upstream of the intake manifold and configured to regulate an air flow into the intake manifold, an exhaust manifold configured to receive combustion products from the combustion chamber, a recirculation flow passage configured to convey exhaust gasses from the exhaust manifold to the intake manifold, a recirculation flow control valve configured to regulate gas flow through the recirculation flow passage, and a controller configured to determine that the engine system is in a motoring condition, open, during the motoring condition and based the determining, the recirculation flow control valve, and close, during the motoring condition and based the determining, the intake valve.