An engine controller controlling an engine including an occlusion reduction catalyst in an exhaust device includes a fuel injection controller that controls a fuel injection amount of an injector, an EGR controller that controls an EGR device, a sulfur purge determiner that determines whether sulfur purging of the catalyst is to be performed, and a sulfur purge controller that executes sulfur purge control if the sulfur purging is performed. The sulfur purge control involves performing a fuel injection to achieve a rich air-fuel ratio at an inlet of the catalyst and prohibiting the exhaust-gas introduction. The sulfur purge controller executes sulfur-purge standby control when a sulfur-purge standby condition is satisfied, and resumes the sulfur purge control when the condition becomes non-satisfied after starting the sulfur-purge standby control. The sulfur-purge standby control involves performing the fuel injection to nearly achieve a stoichiometric air-fuel ratio and prohibiting the exhaust-gas introduction.

Systems and methods for operating a spark ignition engine that includes a particulate filter in the engine's exhaust system are described. In one example, the spark ignition engine is prevented from exceeding a threshold engine load when the engine is supplying power to an electric machine so that engine emissions may be reduced.

A catalyst warming apparatus includes an air blower, a fuel feeder, and an air blowing controller. The air blower is disposed between an engine and a purification catalyst in an exhaust pipe communicating with the engine and is configured to blow air toward the purification catalyst. The fuel feeder is configured to cause the purification catalyst to retain fuel. The air blowing controller is configured to start driving the air blower at a predetermined start timing before a start of the engine.

A method of controlling regeneration of a particulate filter which traps particulate matter contained in an exhaust gas may include: raising, by a controller, a temperature of the exhaust gas to regenerate the particulate filter by burning the trapped particulate matter when an amount of the particulate matter trapped in the particulate filter is greater than or equal to a predetermined amount. Raising the temperature of the exhaust gas may include: raising the temperature of the exhaust gas based on a first temperature difference compensation, and raising the temperature of the exhaust gas based on a second temperature difference compensation. In particular, the first and second temperature difference compensations are calculated based on a target temperature of the exhaust gas at an upstream of the particulate filter and an actual temperature of the exhaust gas at the upstream of the particulate filter.

An apparatus comprises a first circuit and a second circuit. The first circuit is structured to determine that a combustion cylinder is operating in a transition period between an exhaust stroke and an intake stroke of the combustion cylinder. The second circuit is structured to provide an injection command during the transition period to a fuel injector associated with the combustion cylinder, the injection command being to inject fuel into a combustion chamber of the combustion cylinder such that at least a portion of the fuel escapes from the combustion chamber through an exhaust port of the combustion cylinder.

A work vehicle including a DPF system configured to collect particulate matter contained in exhaust gas from an engine; an SCR system configured to add, to the exhaust gas from the engine a reductant stored in a reductant storage tank to reduce nitrogen oxide contained in the exhaust gas; and a control unit capable of executing a DPF renewal control whereby particulate matter collected and deposited in the DPF system is burned and removed by using the exhaust gas from the engine and an SCR reference operation restricting control to restrict an operating condition of the engine. The SCR reference operation restricting control is executed when an amount of the reductant stored in the reductant storage tank is a preset amount or less, or when an abnormality occurs in the SCR system. The control unit preferentially executes the DPF renewal control over the SCR reference operation restricting control.

A controller for an internal combustion engine includes a fuel introduction process of introducing an air-fuel mixture containing fuel injected by a fuel injection valve into an exhaust passage without burning the air-fuel mixture in a cylinder. The fuel introduction processor is configured to perform, during the execution of the fuel introduction process, a determination process of determining whether afterfire, in which the air-fuel mixture burns at an upstream side of a three-way catalyst device in the exhaust passage, has occurred and a stopping process of stopping the fuel introduction process when determining in the determination process that the afterfire has occurred.

A method of controlling regeneration of a particulate filter which traps particulate matter contained in an exhaust gas may include: raising, by a controller, a temperature of the exhaust gas to regenerate the particulate filter by burning the trapped particulate matter when an amount of the particulate matter trapped in the particulate filter is greater than or equal to a predetermined amount. Raising the temperature of the exhaust gas may include: raising the temperature of the exhaust gas based on a first temperature difference compensation, and raising the temperature of the exhaust gas based on a second temperature difference compensation. In particular, the first and second temperature difference compensations are calculated based on a target temperature of the exhaust gas at an upstream of the particulate filter and an actual temperature of the exhaust gas at the upstream of the particulate filter.

Methods and systems are provided for identifying when an exhaust valve of an engine cylinder is not functioning as desired while the engine is being operated to raise a temperature of an exhaust system emissions control device, and in turn taking mitigating action. Thus, in one example a method comprises adjusting an amount of fuel that is provided to each of a plurality of cylinders of an engine during an exhaust stroke of the engine in response to an indication of degraded combustion stemming from a cylinder of the engine. In this way, the engine may continue to be operated to raise the temperature of the exhaust system emissions control device, while mitigating the issue of the degraded combustion.

Methods and systems are provided for identifying when an exhaust valve of an engine cylinder is not functioning as desired while the engine is being operated to raise a temperature of an exhaust system emissions control device, and in turn taking mitigating action. Thus, in one example a method comprises adjusting an amount of fuel that is provided to each of a plurality of cylinders of an engine during an exhaust stroke of the engine in response to an indication of degraded combustion stemming from a cylinder of the engine. In this way, the engine may continue to be operated to raise the temperature of the exhaust system emissions control device, while mitigating the issue of the degraded combustion.